January 2010
Volume 51, Issue 1
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Retina  |   January 2010
Three-Dimensional Profile of Macular Retinal Thickness in Normal Japanese Eyes
Author Affiliations & Notes
  • Sotaro Ooto
    From the Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Kyoto, Japan;
  • Masanori Hangai
    From the Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Kyoto, Japan;
  • Atsushi Sakamoto
    From the Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Kyoto, Japan;
  • Atsuo Tomidokoro
    the Department of Ophthalmology, University of Tokyo, Graduate School of Medicine, Tokyo, Japan;
  • Makoto Araie
    the Department of Ophthalmology, University of Tokyo, Graduate School of Medicine, Tokyo, Japan;
  • Tomohiro Otani
    the Department of Ophthalmology, Gunma University School of Medicine, Maebashi, Japan;
  • Shoji Kishi
    the Department of Ophthalmology, Gunma University School of Medicine, Maebashi, Japan;
  • Kenji Matsushita
    the Department of Ophthalmology, Osaka University Medical School, Suita, Japan;
  • Naoyuki Maeda
    the Department of Ophthalmology, Osaka University Medical School, Suita, Japan;
  • Motohiro Shirakashi
    the Division of Ophthalmology and Visual Science, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan;
  • Haruki Abe
    the Division of Ophthalmology and Visual Science, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan;
  • Hisashi Takeda
    the Department of Ophthalmology, Kanazawa University Graduate School of Medical Science, Kanazawa, Japan; and
  • Kazuhisa Sugiyama
    the Department of Ophthalmology, Kanazawa University Graduate School of Medical Science, Kanazawa, Japan; and
  • Hitomi Saito
    the Department of Ophthalmology, Tajimi Municipal Hospital, Tajimi, Japan.
  • Aiko Iwase
    the Department of Ophthalmology, Tajimi Municipal Hospital, Tajimi, Japan.
  • Nagahisa Yoshimura
    From the Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Kyoto, Japan;
  • Corresponding author: Masanori Hangai, Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan; hangai@kuhp.kyoto-u.ac.jp
Investigative Ophthalmology & Visual Science January 2010, Vol.51, 465-473. doi:10.1167/iovs.09-4047
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      Sotaro Ooto, Masanori Hangai, Atsushi Sakamoto, Atsuo Tomidokoro, Makoto Araie, Tomohiro Otani, Shoji Kishi, Kenji Matsushita, Naoyuki Maeda, Motohiro Shirakashi, Haruki Abe, Hisashi Takeda, Kazuhisa Sugiyama, Hitomi Saito, Aiko Iwase, Nagahisa Yoshimura; Three-Dimensional Profile of Macular Retinal Thickness in Normal Japanese Eyes. Invest. Ophthalmol. Vis. Sci. 2010;51(1):465-473. doi: 10.1167/iovs.09-4047.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract

Purpose.: To demonstrate the three-dimensional macular thickness distribution in normal subjects by spectral domain optical coherence tomography (SD-OCT) and evaluate its association with sex, age, and axial length.

Methods.: Mean regional retinal thickness measurements on the Early Treatment Diabetic Retinopathy Study (ETDRS) layout were obtained by three-dimensional raster scanning (6 × 6 mm) using SD-OCT in 248 normal eyes of 248 Japanese subjects.

Results.: Mean foveal thickness was 222 ± 19 μm; it was significantly greater in men (226 ± 19 μm) than in women (218 ± 18 μm; P = 0.002) and did not correlate with age in either sex. Mean sectoral retinal thickness was also significantly greater in the men than in the women in all the quadrants of the inner ring (1–3 mm; P < 0.001 and P = 0.001–0.007) and in the temporal quadrant of the outer ring (3–6 mm; P < 0.001). The retinal thicknesses of each of the ETDRS sectors did not correlate significantly with axial length after adjustment for age in either sex. Retinal thickness in six of the eight sectors in the inner and outer rings showed a negative correlation with age after adjustment for axial length in the men (P < 0.001 and P = 0.001–0.018), whereas no correlation with age was observed in the women.

Conclusions.: SD-OCT demonstrated the three-dimensional macular thickness distribution in normal eyes. Macular thickness varied significantly with sex and age. These variables should be considered while evaluating macular thickness.

Macular retinal thickness measurement with optical coherence tomography (OCT) 1 instruments is an established method for diagnosing and monitoring macular edema and for evaluating the efficacy of medical and surgical treatments for macular diseases. This method is also effective in discriminating glaucomatous from normal eyes. These quantitative diagnostic analyses of macular thickness are based on an understanding of three-dimensional (3-D) macular dimensions. Several reports on normal macular thickness measurements used time-domain OCT (TD-OCT) instruments, such as prototype OCT, OCT1, OCT2000 (Carl Zeiss Meditec, Dublin, CA), and Stratus OCT (Carl Zeiss Meditec). 221 These studies demonstrated correlations between normal regional macular dimensions, such as the central foveal thickness and retinal thickness of the foveal and extrafoveal sectoral regions, with clinical factors such as age, sex, and axial length. However, accurate 3-D macular dimension data acquisition is limited by the imaging speed and axial resolution of TD-OCT instruments. 
The macula comprises multiple layers with differing configurations and symmetry. Pathologic changes in the morphology of the macula are not necessarily identical in each layer or in each quadrant. Since TD-OCT has a low imaging speed, a dense axial scan cannot be obtained from whole macular regions. Therefore, mean macular thickness was previously calculated based on only six or fewer radial linear scans of 3 to 6 mm each, requiring interpolation to fill in the nonimaged areas. This sparse sampling density is inadequate, especially for profiling the extrafoveal macular configuration. Further, during radial scanning, each scan centering at the fovea is not necessarily registered, owing to the low imaging speed. 22  
Furthermore, previous TD-OCT studies considered retinal thickness as the distance between the vitreoretinal interface and the anterior border of the photoreceptor inner and outer segment junction (IS/OS), thereby excluding the OS length from the normative retinal thickness data. 221 Because TD-OCT imaging with an axial resolution of ∼10 μm was insufficient to completely distinguish the three highly reflective lines representing the presumed IS/OS, outer segment tip, and RPE, the anterior border of the IS/OS line and not that of the RPE was used. 
OCT has recently evolved into spectral-domain OCT (SD-OCT), which utilizes spectral domain detection to achieve 43 to 100 times higher imaging speeds as well as higher signal-to-noise ratio than TD-OCT. 2330 Present SD-OCT instruments contain a light source with a broader bandwidth (50 nm) and have approximately twice the axial resolution (∼5–7 μm) than that obtained with the Stratus OCT (contains a 20-nm bandwidth light source). Remarkable improvements in imaging are expected to overcome the limitations of TD-OCT instruments, providing more accurate and reproducible macular dimensions with increased number and density of sampling points over the entire macula, especially with the 3-D raster scan, and the segmentation of the whole sensory retina. In fact, several reports 31,32 showed that macular retinal thickness measurements obtained by 3-D imaging using SD-OCT instruments are more reproducible than those obtained using TD-OCT. Moreover, macular foveal and extrafoveal thicknesses of 13 normal eyes measured by an SD-OCT instrument (HD-OCT; Carl Zeiss Meditec) were 45.4- to 62.3-μm thicker than those measured by the Stratus OCT. 33  
We performed 3-D raster scanning using 3-D OCT-1000 to measure the mean regional retinal thickness on the Early Treatment Diabetic Retinopathy Study (ETDRS) layout in numerous normal Japanese subjects and evaluated the effects of age, sex, and axial length on foveal and extrafoveal regional retinal thicknesses. 
Methods
Macular thickness data were collected from seven Japanese clinical centers: Kyoto University (Kyoto, Japan), University of Tokyo (Tokyo, Japan), Gunma University (Maebashi, Japan), Osaka University (Suita, Japan), Niigata University (Niigata, Japan), Kanazawa University (Kanazawa, Japan), and Tajimi Municipal Hospital (Tajimi, Japan). The Institutional Review Board and Ethics Committee of each participating center approved the study, which adhered to the tenets of the Declaration of Helsinki. Written informed consent was obtained from each subject after the study protocol was explained. 
Self-reported ophthalmologically healthy subjects at least 20 years of age were recruited in the study according to the predetermined number of subjects in the six age groups, ensuring an even distribution of subjects per sex and age group. Ocular examination at the first visit included auto ref-keratometry, uncorrected and best-corrected visual acuity measurements with the 5-m Landolt chart, axial length measurement using ocular biometry (IOLMaster; Carl Zeiss Meditec), slit lamp examinations, intraocular pressure measurements with a Goldmann applanation tonometer, dilated funduscopy, and visual field testing (Humphrey 24-2 Swedish Interactive Threshold Algorithm with the HFA; Carl Zeiss Meditec). 
Exclusion criteria were as follows: contraindication to dilation; best-corrected visual acuity worse than 20/25; refractive error, >5.0 or <−6.0 D; intraocular pressure, ≥22 mm Hg; unreliable HFA results (fixation loss or false-positive or -negative, >33%); abnormal HFA findings suggesting glaucoma according to the Anderson and Patella criteria 34 ; any abnormal visual field loss consistent with ocular disease; history of intraocular surgery; evidence of vitreoretinal diseases; and evidence of optic nerve or retinal nerve fiber layer (RNFL) abnormality, diabetes mellitus, or other systemic diseases that might affect the eye. SD-OCT examinations of the eligible candidates were performed according to the scan protocols selected by the study group before disc and macula analyses. 
An experienced operator performed OCT scanning using 3-D OCT-1000 after pupillary dilation with 1% tropicamide. Color fundus photographs were taken immediately after OCT scanning. The examination was conducted on both the eyes, if eligible. 3-D imaging data were acquired by using a raster scan protocol of 512 × 128 (horizontal × vertical) axial scans per image (total 65,536 axial scans/image). Each 3-D raster scan covered a 6 × 6-mm area centered at the fixation point in the posterior pole (Fig. 1A) and was obtained in approximately 2.4 seconds. During the measurement, accurate scan lengths were obtained by correcting the magnification effect in each eye by the manufacturer's formula (modified Littman's method), which is based on the refractive error, corneal radius, and axial length. Only good-quality images with a Q factor score of >65 were used. 
Figure 1.
 
Segmentation of the two border lines for macular thickness on 3-D SD-OCT imaging. (A) A volume-rendering 3-D image on the raster scan comprising 512 A-scans × 128 B-scans. Each scan covers a 6 × 6-mm2 area centered at the fixation point in the posterior pole. (B) Segmentation of the vitreoretinal interface (anterior border of internal limiting membrane [ILM]) and the anterior border of the retinal pigment epithelium (RPE) for macular thickness measurement. The 3-D optical coherence tomography (OCT)-1000 built-in software performs automated segmentation of the borders. Border planes reconstructed by volume-rendering are shown.
Figure 1.
 
Segmentation of the two border lines for macular thickness on 3-D SD-OCT imaging. (A) A volume-rendering 3-D image on the raster scan comprising 512 A-scans × 128 B-scans. Each scan covers a 6 × 6-mm2 area centered at the fixation point in the posterior pole. (B) Segmentation of the vitreoretinal interface (anterior border of internal limiting membrane [ILM]) and the anterior border of the retinal pigment epithelium (RPE) for macular thickness measurement. The 3-D optical coherence tomography (OCT)-1000 built-in software performs automated segmentation of the borders. Border planes reconstructed by volume-rendering are shown.
To assess the interobserver reproducibility of macular thickness measurements by 3-D OCT-1000, the same macular scan protocol was performed separately by two operators on the same day in 31 subjects. Intervisit reproducibility was assessed in 48 subjects by an additional scanning by the same operator at an interval of 1 to 3 months. 
Three glaucoma experts (MA, HA, AI) and two macular experts (NY, SK) from the seven centers examined all the acquired color fundus photographs and reached a consensus on whether each eye had evidence of glaucomatous optic neuropathy or other optic nerve abnormalities and on whether each eye had evidence of retinal disease, respectively. 
All 3-D-OCT scan data were sent to the Kyoto University OCT Reading Center at the Kyoto University Graduate School of Medicine (Kyoto, Japan). B-scan images were analyzed with the 3-D OCT-1000 built-in software (version 3.01) to calculate macular thickness—the distance between the vitreoretinal interface and the inner border of the highly reflective line representing the RPE (Fig. 1B). Mean sectoral thicknesses were displayed in the nine macular sectors determined by the ETDRS. The inner and outer rings had diameters of 1 to 3 and 3 to 6 mm, respectively, and were segmented into superior, inferior, temporal, and nasal quadrants. A smaller outer-ring layout (diameter, 3–5 mm) was also analyzed (Fig. 2). 3-D scans were visually inspected and excluded if there were any B-scans with an algorithm failure, such as inaccurately drawn automated boundary lines. The center of the ETDRS circle of each image and the central fovea were manually placed together if they were not aligned. Each B-scan was checked by four expert graders, and only the images that were approved by all the four graders as having appropriate segmentation lines were included in the study. If both the eyes were eligible, one eye of each subject was randomly selected for the analyses. 
Figure 2.
 
ETDRS layout and modified ETDRS layout with a smaller outer ring (dashed circular line).
Figure 2.
 
ETDRS layout and modified ETDRS layout with a smaller outer ring (dashed circular line).
The effect of age, sex, and axial length on macular thickness was determined by univariate analysis. For comparing retinal thickness variables among sectors, the paired t-test and Friedman test were used. Variables between sexes were compared using an unpaired t-test. For interobserver and intervisit measurements, coefficients of variation (CVs) were obtained by dividing the within-subject standard deviation by the within-subject mean. Statistical analyses were performed by using a commercially available software program (SPSS2; SPSS Japan Inc., Tokyo, Japan). P < 0.05 was considered statistically significant. 
Results
Two hundred forty-eight normal eyes of 248 Japanese subjects (127 men [51%], 121 women [49%]) were enrolled in the study, and an additional 426 eyes of 213 subjects were screened but excluded from the study (Table 1). The age of the enrolled subjects ranged from 20 to 77 years (median, 48.6 years). The number and demographic data of the enrolled subjects in each age group are shown in Table 1. Mean age of the men was 49.1 ± 17.3 years and that of the women was 48.1 ± 16.6 years (P = 0.667, unpaired t-test). The mean axial length was 24.1 ± 0.9 in the men and 23.5 ± 0.9 in the women (P = 0.08, unpaired t-test). 
Table 1.
 
Demographic Data of Included Subjects
Table 1.
 
Demographic Data of Included Subjects
Age Group (y) n Men/Women (ratio) Refractive Errors (D) Axial Length (mm) IOP (mm Hg)
20–29 46 25/21 (1.2) −1.8 ± 1.7 24.3 ± 1.0 13.5 ± 2.2
30–39 42 18/24 (0.75) −1.3 ± 1.2 24.0 ± 0.9 14.1 ± 2.5
40–49 34 19/15 (1.3) −1.0 ± 1.1 24.0 ± 0.8 14.6 ± 2.3
50–59 43 19/24 (0.8) −0.6 ± 1.6 23.7 ± 1.1 13.8 ± 2.7
60–69 52 28/24 (1.2) 0.2 ± 1.1 23.4 ± 0.8 14.4 ± 2.3
70+ 31 18/13 (1.4) 0.7 ± 1.4 23.3 ± 0.8 14.0 ± 2.2
Total 248 127/121 (1.0) −0.7 ± 1.6 23.8 ± 1.0 14.1 ± 2.4
CVs are shown in Table 2. Within-subject SD and mean interobserver or intervisit measurements did not differ significantly. Results for the smaller outer-ring region were similar (5-mm diameter), as shown in Supplementary Table S1
Table 2.
 
Reproducibility of Normal Macular Thickness Measurement Using 3D-OCT
Table 2.
 
Reproducibility of Normal Macular Thickness Measurement Using 3D-OCT
Interobserver (n = 31) Intervisit (n = 48)
Fovea (1 mm) 1.6 ± 0.2 1.7 ± 0.2
Inner ring (3 mm)
    Temporal 0.9 ± 0.1 0.9 ± 0.1
    Superior 1.3 ± 0.1 0.9 ± 0.1
    Nasal 0.9 ± 0.1 1.0 ± 0.1
    Inferior 1.0 ± 0.1 0.9 ± 0.1
Outer ring (6 mm)
    Temporal 1.3 ± 0.1 1.3 ± 0.1
    Superior 1.3 ± 0.1 1.2 ± 0.1
    Nasal 0.7 ± 0.1 1.0 ± 0.1
    Inferior 1.4 ± 0.1 1.3 ± 0.1
The mean retinal thickness of each ETDRS sector is shown in Table 3. Mean retinal thickness in the nasal quadrant was greater than that in the other quadrants (P < 0.001, Friedman test), and it was smaller in the outer ring than in the inner ring (P < 0.001, paired t-test). Superior macular thickness was significantly greater than the inferior macular thickness, both in the inner (P < 0.001, paired t-test) and outer rings (P < 0.001, paired t-test). Mean foveal thickness (in the central 1-mm diameter of the ETDRS layout) was 221.93 ± 18.83 μm (range, 178.32–288.02). 
Table 3.
 
Sex Difference in Macular Thickness Measurements
Table 3.
 
Sex Difference in Macular Thickness Measurements
Total (n = 248) Men (n = 127) Women (n = 121) P *
Fovea (1 mm) 221.93 ± 18.83(178.32–288.02) 225.58 ± 19.13(178.32–288.02) 218.10 ± 17.79(178.41–272.57) 0.002
Inner ring (3 mm)
    Temporal 284.86 ± 13.96(247.85–334.60) 288.33 ± 14.32(255.99–334.56) 281.22 ± 12.65(247.85–318.42) <0.001
    Superior 296.73 ± 14.51(259.90–340.73) 299.37 ± 15.26(267.94–340.73) 293.96 ± 13.12(259.90–337.12) 0.003
    Nasal 299.22 ± 15.28(263.41–345.77) 301.76 ± 16.68(268.03–345.77) 296.56 ± 13.20(263.41–338.61) 0.007
    Inferior 293.51 ± 14.47(255.90–331.86) 296.43 ± 14.78(259.62–331.86) 290.44 ± 13.54(255.90–329.32) 0.001
Outer ring (6 mm)
    Temporal 243.59 ± 12.26(212.96–280.13) 246.39 ± 11.68(220.02–280.13) 240.65 ± 12.21(212.96–274.76) <0.001
    Superior 257.12 ± 12.87(225.11–297.42) 257.49 ± 12.13(229.88–289.27) 256.73 ± 13.64(225.11–297.42) 0.643
    Nasal 273.44 ± 14.07(236.37–320.17) 273.99 ± 14.01(242.74–309.48) 272.84 ± 14.15(236.37–320.17) 0.522
    Inferior 246.69 ± 13.00(215.29–281.47) 247.74 ± 12.51(215.92–281.46) 245.56 ± 13.43(215.29–276.02) 0.193
Mean foveal thickness was significantly greater in the men than in the women (P = 0.002, unpaired t-test; Table 3). Mean sectoral retinal thickness was also significantly greater in the men than in the women in all the quadrants of the inner ring (P < 0.001 and P = 0.001–0.007, unpaired t-test) and in the temporal quadrant of the outer ring (P < 0.001, unpaired t-test). Supplementary Table S2 shows the retinal thickness by sex in the 5-mm outer subfields. The retinal thickness of the temporal and inferior quadrants was significantly greater in the men than in the women (P < 0.001 and P = 0.013, unpaired t-test). 
The retinal thickness of none of the ETDRS sectors significantly correlated with axial length after adjustment for age, irrespective of the sex (Table 4). Figure 3 shows the regression plot for foveal thickness (1-mm diameter) versus axial length. 
Table 4.
 
Partial Correlation between Axial Length and Macular Thickness after Adjustment for Age
Table 4.
 
Partial Correlation between Axial Length and Macular Thickness after Adjustment for Age
P (Adjusted for Age)*
Fovea (1 mm) 0.631
Inner ring (3 mm)
    Temporal 0.600
    Superior 0.714
    Nasal 0.612
    Inferior 0.547
Outer ring (6 mm)
    Temporal 0.088
    Superior 0.536
    Nasal 0.548
    Inferior 0.813
Figure 3.
 
Regression plot of foveal thickness (1-mm diameter) versus axial length. There was no statistical correlation between the two variables.
Figure 3.
 
Regression plot of foveal thickness (1-mm diameter) versus axial length. There was no statistical correlation between the two variables.
After adjustment for axial length, foveal thickness did not correlate with age (Table 5, Fig. 4A), although retinal thickness in five of the eight sectors in the inner and outer rings significantly correlated with age (Table 5, Fig. 4B). The retinal thinning rate with age was from −0.14 to −0.22 μm per year. 
Table 5.
 
Correlation between Age and Macular Thickness with Pearson's Correlation Coefficient and Partial Correlation Coefficient after Adjustment for Axial Length
Table 5.
 
Correlation between Age and Macular Thickness with Pearson's Correlation Coefficient and Partial Correlation Coefficient after Adjustment for Axial Length
Regression (×Age) R 2 P * P (adjusted for AL)†
Fovea (1 mm) 222.26–0.01 0 0.926 0.926
Inner ring (3 mm)
    Temporal 289.77–0.10 0.02 0.054 0.111
    Superior 304.56–0.16 0.04 0.003 0.004
    Nasal 307.53–0.17 0.04 0.003 0.003
    Inferior 299.64–0.13 0.02 0.02 0.053
Outer ring (6 mm)
    Temporal 246.95–0.07 0.01 0.134 0.448
    Superior 265.28–0.17 0.05 <0.001 0.002
    Nasal 284.13–0.22 0.07 <0.001 <0.001
    Inferior 253.42–0.14 0.03 0.004 0.01
Figure 4.
 
Representative regression plot of sectoral retinal thickness versus age. (A) Foveal retinal thickness (1-mm diameter) versus age. There was no significant correlation between foveal thickness and age. (B) Representative plot of retinal thickness in the nasal outer sector versus age. Retinal thickness correlated negatively with age (P < 0.001).
Figure 4.
 
Representative regression plot of sectoral retinal thickness versus age. (A) Foveal retinal thickness (1-mm diameter) versus age. There was no significant correlation between foveal thickness and age. (B) Representative plot of retinal thickness in the nasal outer sector versus age. Retinal thickness correlated negatively with age (P < 0.001).
Foveal thickness did not correlate significantly with age in either sex (Tables 6, 7; Fig. 5), whereas retinal thickness in six of the eight sectors in the inner and outer rings had a negative correlation with age after adjustment for axial length in the men (P < 0.001 and P = 0.001–0.018; Table 6, Fig. 6, and Supplementary Figs. S1–S7). The retinal thinning rate with age was from −0.21 to −0.32 μm per year in the men. In the temporal sectors of the inner and outer rings, retinal thickness tended to decay in an age-dependent manner, but not significantly (P = 0.056 and 0.082, respectively, after adjustment for axial length), whereas that in the extrafoveal sectors did not significantly correlate with age in the women (Table 7, Fig. 6, Supplementary Figs. S1–S7). The relationship between ETDRS sectoral retinal thickness and age was similar between men and women in the 5-mm outer subfields (Supplementary Table S3). 
Table 6.
 
Correlation between Age and Macular Thickness with Pearson's Correlation Coefficient and Partial Correlation Coefficient after Adjustment for Axial Length in the Men
Table 6.
 
Correlation between Age and Macular Thickness with Pearson's Correlation Coefficient and Partial Correlation Coefficient after Adjustment for Axial Length in the Men
Regression (×Age) R 2 P * P (adjusted for AL)†
Fovea (1 mm) 221.68–0.08 0.01 0.421 0.74
Inner ring (3 mm)
    Temporal 295.13–0.14 0.03 0.06 0.056
    Superior 310.44–0.23 0.07 0.004 0.005
    Nasal 314.96–0.27 0.08 0.001 0.001
    Inferior 306.65–0.21 0.06 0.006 0.018
Outer ring (6 mm)
    Temporal 252.52–0.12 0.03 0.037 0.082
    Superior 269.63–0.25 0.12 <0.001 0.001
    Nasal 289.77–0.32 0.16 <0.001 <0.001
    Inferior 257.88–0.21 0.08 0.001 0.002
Table 7.
 
Correlation between Age and Macular Thickness with Pearson's Correlation Coefficient and Partial Correlation Coefficient after Adjustment for Axial Length in the Women
Table 7.
 
Correlation between Age and Macular Thickness with Pearson's Correlation Coefficient and Partial Correlation Coefficient after Adjustment for Axial Length in the Women
R 2 P * P (adjusted for AL)†
Fovea (1 mm) 0.01 0.229 0.299
Inner ring (3 mm)
    Temporal 0.01 0.31 0.219
    Superior 0.01 0.181 0.059
    Nasal 0.01 0.349 0.149
    Inferior 0 0.564 0.329
Outer ring (6 mm)
    Temporal 0 0.819 0.945
    Superior 0.01 0.295 0.341
    Nasal 0.02 0.172 0.112
    Inferior 0.01 0.383 0.385
Figure 5.
 
Regression plot of foveal thickness (1-mm diameter) versus age in each sex. No significant correlation was observed in either sex.
Figure 5.
 
Regression plot of foveal thickness (1-mm diameter) versus age in each sex. No significant correlation was observed in either sex.
Figure 6.
 
Representative regression plots of extrafoveal sectoral retinal thickness versus age in the men and women. Representative plots of the nasal outer sector. Retinal thickness of the nasal outer sector significantly correlated with age in the men (P < 0.001), whereas there was no significant correlation between retinal thickness and age in the women. The retinal thinning rate with age in the men was −0.32 μm per year.
Figure 6.
 
Representative regression plots of extrafoveal sectoral retinal thickness versus age in the men and women. Representative plots of the nasal outer sector. Retinal thickness of the nasal outer sector significantly correlated with age in the men (P < 0.001), whereas there was no significant correlation between retinal thickness and age in the women. The retinal thinning rate with age in the men was −0.32 μm per year.
Discussion
Many studies measured macular thickness using TD-OCT instruments to profile the macular regional dimensions and their relation to factors, such as age, sex, and axial length. However, measuring macular dimensions using TD-OCT has several limitations. First, the imaging speed of TD-OCT is inadequate to cover the entire macular region with a high sampling density. This limitation is especially critical for measuring macular dimensions, because the macula comprises several layers that do not have identical 3-D profiles and are not damaged in an identical manner. Second, TD-OCT instruments consider retinal thickness as the distance between the vitreoretinal interface and the anterior border of the IS/OS line because the IS/OS, outer segment tip, and RPE lines are not clearly distinguished; thus, the OS length has been excluded from the retinal thickness of many previous studies. In this study, we used a 3-D raster scan of 65,536 sampling points (512 horizontal × 128 vertical) in a 6 × 6-mm2 compared with the 768 sampling points on six radial scans of the Stratus OCT and measured the retinal thickness as the distance between the vitreoretinal interface and the anterior border of the RPE line with a commercially available SD-OCT instrument. 
We analyzed many ophthalmically normal subjects, with at least 31 subjects per age group and an almost even distribution of sexes across every age group. Therefore, a generalized relationship between macular dimensions and important subject variables, such as age, sex, and axial length is more likely to be obtained. 
The clinical utility of any instrument depends on the reproducibility of its measurements. In previous Stratus OCT studies, interobserver and intervisit reproducibility of macular thickness measurements after pupil dilation on the ETDRS layout varied from 4.06% to 9.4% 3537 and from 5.52% to 8.51%, 13,36 respectively, for mean foveal thickness and from 2.15% to 6.97% 36 and from 1.48% to 8.63%, 13,36 respectively, for sectoral thickness. In our study, the interobserver and intervisit CVs for mean foveal thickness were 1.6% and 1.7%, respectively, and ranged from 0.7% to 1.4% and from 0.9% to 1.3%, respectively for sectoral thickness. Neither interobserver nor intervisit reproducibility of macular thickness measurements using SD-OCT has been reported. Although reproducibility and repeatability are not identical, our CVs are similar to the macular thickness measurement repeatability reported by Leung et al., 31 who showed that 3-D raster-scan imaging using SD-OCT (3-D-OCT 1000) has a better measurement repeatability (mean foveal thickness, 2.42%; sectoral thickness, 0.62%–1.00%) than that of the six radial scans obtained with the Stratus OCT (mean foveal thickness, 3.21%; sectoral thickness, 1.62%–2.23%). Kakinoki et al. 32 reported a good measurement repeatability of 0.7% to 1.3% for Stratus OCT, but a significantly better measurement repeatability for another type of SD-OCT (HD-OCT). 
Foveal thickness (average thickness in the central 1000-μm diameter area) in our study (222 ± 19 μm) was greater by 10 to 52 μm than that reported in previous studies using TD-OCT instruments, such as the prototype OCT, OCT1, and Stratus OCT (170–212 μm). 3,8,13,1421 In our study, entire macular thickness was considered to be the distance between the vitreoretinal interface and the inner border of the RPE line. In previous TD-OCT studies, retinal thickness was considered to be the distance between the vitreoretinal interface and the inner border of the IS/OS line, excluding the outer segment layer thickness. Recently, Leung et al. 31 reported that the macular fovea in 35 normal eyes was thicker by 20.8 μm when 3-D OCT-1000 was used (216.4 μm) compared with when Stratus OCT was used (195.6 μm). Recently, two other studies reported greater differences in foveal thickness between Stratus OCT and HD-OCT: Legarreta et al. 33 showed that the foveal thickness in 13 normal eyes was 258.2 μm with HD-OCT and 212 μm with Stratus OCT, and Kakinoki et al. 32 reported that foveal thickness in 50 normal eyes was 256.7 μm using HD-OCT and 197.2 μm using Stratus OCT. Both the SD-OCT instruments measured retinal thickness as the distance between the vitreoretinal interface and the inner border of the RPE line. In the histologic study by Yamada, 38 the thickness of the outer segment between the IS/OS and RPE was approximately 45 μm. Grover et al. 39 reported that the mean foveal thickness in 50 normal eyes was 270.2 μm when determined by a different type of SD-OCT instrument (Spectralis; Heidelberg Engineering, Dossenheim, Germany), which measures retinal thickness considering the distance between the vitreoretinal interface and the outer border of the RPE line. Thus, the greater mean foveal thickness obtained by using SD-OCT instruments in our study and previous studies compared with that obtained using the Stratus OCT seems to be partly due to the difference in the retinal thickness definition. 
In our study, the thickness in the nasal sector was much greater than that in the other three sectors within the outer ring (nasal ≫ superior > inferior > temporal), whereas there were no large differences between the inner ring sectors, consistent with previous Stratus OCT studies. 15,1721,31 Greater asymmetry of the macula thickness of the outer ring compared with that of the inner ring may be due to the vertically symmetric, but horizontally asymmetric anatomic nature of the RNFL, in which converging retinal nerve fibers form the superior and inferior arcuate bundles of nerve fibers within the optic disc. In contrast, the ETDRS inner ring corresponds to regions with the thickest total retina and ganglion cell layer and a relatively thin RNFL. The relatively symmetric macular configuration in the inner ring may reflect the symmetric nature of the anatomic configuration of the retinal layers beneath the RNFL. 
We found that the foveal and some of the extrafoveal sectoral thicknesses were significantly greater in the men than in the women. The mean foveal thickness (1000-μm diameter) in our study is consistent with that in four other studies in which the OCT2000 or Stratus OCT was used. 3,14,17,18 The intersex difference (8 μm) in our study was much smaller than that reported in previous studies (12–22 μm). Other Stratus OCT studies reported no significant intersex differences, 14,19 indicating an inconsistency between previous studies in which the same Stratus OCT instrument was used. 14,1719 Stratus OCT has an axial resolution of ∼10 μm and hence requires an appropriately large sample size to detect intersex differences of as small as 8 to 22 μm. The two Stratus OCT studies, which reported foveal thickness greater by 19.5 μm and 21 to 22 μm in the men than in the women, included 143 and 83 subjects, respectively. 17,18 One of the studies that did not detect a significant sex difference (14 μm) included 37 subjects, and only 11 (29.7%) were men, 14 and the other study, reporting a 4-μm difference, used 200 eyes of 100 subjects, but more men (69.69%) were included than women (31.31%). We evaluated 248 subjects with a nearly even sex distribution per age group and used an SD-OCT instrument with an axial resolution of 5 μm. Recently, a study reported a 7.5-μm larger foveal thickness in the men than in the women by using Spectralis, which is consistent with a 7.48-μm difference in our study. 39 However, the difference in the previous study was not statistically significant probably because of the smaller sample size (50 subjects). 
The extrafoveal retinal thickness in the outer ring, except for the temporal outer sector, showed a very small intersex difference. All the inner ring sectors were 5 to 7 μm thicker in men; this was somewhat comparable with the results of two previous Stratus OCT studies. 17,18 Kelty et al. 18 showed that in their 83 Caucasian and African American subjects, the retinal thickness was significantly greater in the right eye in the men (12–20 μm, inner ring; 9 μm, temporal outer ring) in the same sectors as observed in our study, whereas in the left eye, only the nasal sector in the inner ring showed a significant sex difference (12 μm). Other sectors in the inner ring also had a nonsignificant 8- to 9-μm greater mean retinal thickness in the men, unlike a 1- to 3-μm difference in the outer ring. Using 143 Chinese subjects, Lam et al. 17 showed that the retinal thickness in the temporal and superior sectors in the inner ring was significantly greater by 8 to 9 μm in the men; other sectors showed greater mean retinal thickness by 1 to 5 μm, which was not statistically significant. 
One of the studies performed with a retinal thickness analyzer (RTA; Talia Technology Ltd., Neve-Ilan, Israel) 40 showed greater thickness in the central 20° of the posterior pole in African American men. Two other studies did not detect an intersex difference in the mean foveal thickness (1200 μm diameter). 41,42 Zou et al. 41 did not find significant inter-sex differences in the retinal thickness in any extrafoveal regions, and in contrast to our results and those of Asrani et al., 40 Chan et al. 42 reported that Chinese women had 8-μm thicker retinas in the perifoveal and posterior pole regions. Because the RTA functions on the principle of slit-lamp fundus biomicroscopy and bi-Lorentzian curve fitting is performed to delineate the internal limiting membrane and RPE with an axial resolution of approximately 50 μm, 4042 it is uncertain whether this instrument can resolve the 5- to 9-μm intersex differences observed in our study. 
Most previous studies reported no intersex difference in mean circumpapillary RNFL thickness. 11,4347 The lack of an intersex difference in outer-ring thickness in the previous studies may be because of the influence of the superior and inferior arcuate configuration of the RNFL. The intersex difference in the temporal–outer sector may be attributable to the smallest RNFL thickness in the temporal raphe of the extrafoveal region. The retinal thickness external to the RNFL, which constitutes a relatively larger part of the retina may be responsible for the intersex difference in the inner ring. The layer responsible for the intersex difference in retinal thickness is yet unknown. 
Mean foveal thickness did not correlate with age, whereas extrafoveal retinal thickness in five of the eight sectors had a negative correlation with age. It is of interest that this correlation was observed only in the men. An intersex difference in the age-dependent decay of extrafoveal retinal thickness has not been reported. Using Stratus OCT, Eriksson and Alm 21 studied 134 Caucasian eyes without high myopia and reported that the macular thicknesses in all the sectors on the ETDRS layout correlated significantly with age, which is consistent with our results, except for the mean foveal thickness. However, they did not compare the results between sexes. A Stratus OCT study 15 and 2 SD-OCT studies (HD-OCT, in the study by Kakinoki et al. 32 and Spectralis, in the study by Grover et al. 39 ) found no correlation between age and mean foveal thickness (1000-μm diameter), as observed in our study, but none of these studies showed a relationship between extrafoveal thickness and age. Two other OCT2000 studies suggested that macular thickness decreases with age. 9,11 However, it is difficult to compare their results with ours, because their measurement protocols differ greatly from the mean sectoral retinal thickness measurement based on the ETDRS layout used in our study; Alamouti and Funk 11 measured retinal thickness along the 2.3-mm length scan placed at the temporal edge of the optic disc, and Kanai et al. 9 evaluated the mean foveal thickness at the diameters of 1.5 and 2.0 mm, which include both foveal and some extrafoveal regions. Lam et al. 17 detected no correlation between age and any macular measurement on the ETDRS, which is consistent with our results for mean foveal thickness, but conflicts with those for extrafoveal sectoral thickness. Their study included 80 eyes (56%) with high myopia (spherical equivalent < −6.00) of the total 143 eyes, and the mean retinal thickness in the outer ring significantly differed between highly myopic and nonmyopic to moderately myopic eyes. Thus, the inclusion of the highly myopic eyes may have accounted for the discrepancy. 
Various histologic studies have reported substantial axon fiber loss per year. 48,49 Consistent with these studies, most OCT studies indicate significant decreases in the mean circumpapillary or peripapillary RNFL thickness with age. 11,44,45 Alamouti and Funk, 11 Parikh et al., 46 and Budenz et al. 47 reported a regression slope of −0.44, −0.16, and −0.20 μm/year, respectively. Our results indicate a significant linear decrease in mean extrafoveal sectoral macular thickness with age in the men, with a negative slope ranging from −0.12 to −0.32 μm/year. The retinal thickness in the temporal quadrant with the thinnest RNFL was the most resistant to age-dependent decay. Furthermore, age did not correlate with the mean foveal thickness at a 1-mm diameter where the RNFL thickness is negligible. Thus, age-related decay of extrafoveal macular retinal thickness seems to be due partly to the age-related decay of RNFL thickness. An intersex difference in the age-dependent decay of RNFL thickness has not been reported. 
We found no correlation between macular sectoral thickness and age-adjusted axial length; a finding somewhat inconsistent with that of the two studies using the OCT II or Stratus OCT, in which foveal minimum (central foveal) and/or mean foveal (1-mm diameter) thickness correlated with axial length. 16,17 Lam et al. 17 used Stratus OCT and showed a correlation between foveal thickness and axial length and a negative correlation between sectoral thickness in the outer ring and axial length, whereas the thickness of the four sectors in the inner ring did not correlate with axial length. Lim et al. 16 used OCT 1 and showed that minimum foveal and maximum thicknesses correlated with axial length. These two studies differ from ours in that they included highly myopic eyes. Our results were consistent with those of an OCT2000 study, 12 which included highly myopic eyes, and two RTA studies, one of which included highly myopic eyes. 41,42 These three studies indicated no correlation between foveal or extrafoveal thickness and axial length. The results of one of the studies that included highly myopic eyes were consistent with those of ours, whereas those of the others were not. Unfortunately, these previous studies did not adjust for age. Because the findings of our study and those of a few previous studies suggest a correlation between macular retinal thickness and age, age-adjusted analysis is required for precise interpretation. Moreover, fundus dimensions are affected by magnification errors caused by axial length and refraction error, but magnification correction using Littman's method, as performed in our study, was implemented in only one OCT1 study, 16 in which, unfortunately, only a vertical scan was performed. 
Our study has a limitation: the 3-D-OCT raster-scan protocol may not cover the entire ETDRS region in some eyes, because, although the ETDRS layout falls within a 6-mm diameter circle, the raster scan covers only a 6 × 6-mm area with identical horizontal and vertical dimensions. Thus, if the central fovea and the central point of the ETDRS layout do not match exactly, the thicknesses of some peripheral areas of the outer ring may be omitted. Similar problems are encountered when obtaining measurements with six radial 6-mm-long linear scans using the Stratus OCT. Therefore, we also evaluated a smaller outer-ring layout (5-mm diameter) and obtained results similar to those obtained with the standard ETDRS layout. Further, despite a large sample size with a nearly even distribution of age and sex, our study was limited to Japanese subjects without high myopia; this selective sample may limit the interpretation of our results. Foveal and extrafoveal thickness differences between different ethnic groups 18,19 or between the eyes with and without high myopia 17,20 have been reported. The limited inclusion criteria of our study provide a simpler approach for studying the relationship between macular thickness and age, sex, and axial length, without the influence of ethnic differences or high myopia. Nevertheless, the results need to be confirmed in other countries or ethnic groups, as well as in subjects with high myopia. 
Here, the data for regional macular thicknesses in a large, normal, Japanese population were obtained by 3-D raster-scan imaging with a commercially available SD-OCT instrument and software. Although the reasons for the discrepancies between our study and previous studies are not entirely clear, our findings indicate that sex and age must be considered while interpreting macular retinal thickness data. 
Supplementary Materials
Footnotes
 Supported in part by Grant-in-Aid for Scientific Research 20592038 from the Japan Society for the Promotion of Science (JSPS) and Topcon Inc. (Tokyo, Japan).
Footnotes
 Disclosure: S. Ooto, Topcon (F); M. Hangai, Topcon (F); A. Sakamoto, Topcon (F); A. Tomidokoro, Topcon (F); M. Araie, Topcon (F, C); T. Otani, Topcon (F); S. Kishi, Topcon (F); K. Matsushita, Topcon (F); N. Maeda, Topcon (F); M. Shirakashi, Topcon (F); H. Abe, Topcon (F); H. Takeda, Topcon (F); K. Sugiyama, Topcon (F); H. Saito, Topcon (F); A. Iwase, Topcon (F); N. Yoshimura, Topcon (F, C)
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Figure 1.
 
Segmentation of the two border lines for macular thickness on 3-D SD-OCT imaging. (A) A volume-rendering 3-D image on the raster scan comprising 512 A-scans × 128 B-scans. Each scan covers a 6 × 6-mm2 area centered at the fixation point in the posterior pole. (B) Segmentation of the vitreoretinal interface (anterior border of internal limiting membrane [ILM]) and the anterior border of the retinal pigment epithelium (RPE) for macular thickness measurement. The 3-D optical coherence tomography (OCT)-1000 built-in software performs automated segmentation of the borders. Border planes reconstructed by volume-rendering are shown.
Figure 1.
 
Segmentation of the two border lines for macular thickness on 3-D SD-OCT imaging. (A) A volume-rendering 3-D image on the raster scan comprising 512 A-scans × 128 B-scans. Each scan covers a 6 × 6-mm2 area centered at the fixation point in the posterior pole. (B) Segmentation of the vitreoretinal interface (anterior border of internal limiting membrane [ILM]) and the anterior border of the retinal pigment epithelium (RPE) for macular thickness measurement. The 3-D optical coherence tomography (OCT)-1000 built-in software performs automated segmentation of the borders. Border planes reconstructed by volume-rendering are shown.
Figure 2.
 
ETDRS layout and modified ETDRS layout with a smaller outer ring (dashed circular line).
Figure 2.
 
ETDRS layout and modified ETDRS layout with a smaller outer ring (dashed circular line).
Figure 3.
 
Regression plot of foveal thickness (1-mm diameter) versus axial length. There was no statistical correlation between the two variables.
Figure 3.
 
Regression plot of foveal thickness (1-mm diameter) versus axial length. There was no statistical correlation between the two variables.
Figure 4.
 
Representative regression plot of sectoral retinal thickness versus age. (A) Foveal retinal thickness (1-mm diameter) versus age. There was no significant correlation between foveal thickness and age. (B) Representative plot of retinal thickness in the nasal outer sector versus age. Retinal thickness correlated negatively with age (P < 0.001).
Figure 4.
 
Representative regression plot of sectoral retinal thickness versus age. (A) Foveal retinal thickness (1-mm diameter) versus age. There was no significant correlation between foveal thickness and age. (B) Representative plot of retinal thickness in the nasal outer sector versus age. Retinal thickness correlated negatively with age (P < 0.001).
Figure 5.
 
Regression plot of foveal thickness (1-mm diameter) versus age in each sex. No significant correlation was observed in either sex.
Figure 5.
 
Regression plot of foveal thickness (1-mm diameter) versus age in each sex. No significant correlation was observed in either sex.
Figure 6.
 
Representative regression plots of extrafoveal sectoral retinal thickness versus age in the men and women. Representative plots of the nasal outer sector. Retinal thickness of the nasal outer sector significantly correlated with age in the men (P < 0.001), whereas there was no significant correlation between retinal thickness and age in the women. The retinal thinning rate with age in the men was −0.32 μm per year.
Figure 6.
 
Representative regression plots of extrafoveal sectoral retinal thickness versus age in the men and women. Representative plots of the nasal outer sector. Retinal thickness of the nasal outer sector significantly correlated with age in the men (P < 0.001), whereas there was no significant correlation between retinal thickness and age in the women. The retinal thinning rate with age in the men was −0.32 μm per year.
Table 1.
 
Demographic Data of Included Subjects
Table 1.
 
Demographic Data of Included Subjects
Age Group (y) n Men/Women (ratio) Refractive Errors (D) Axial Length (mm) IOP (mm Hg)
20–29 46 25/21 (1.2) −1.8 ± 1.7 24.3 ± 1.0 13.5 ± 2.2
30–39 42 18/24 (0.75) −1.3 ± 1.2 24.0 ± 0.9 14.1 ± 2.5
40–49 34 19/15 (1.3) −1.0 ± 1.1 24.0 ± 0.8 14.6 ± 2.3
50–59 43 19/24 (0.8) −0.6 ± 1.6 23.7 ± 1.1 13.8 ± 2.7
60–69 52 28/24 (1.2) 0.2 ± 1.1 23.4 ± 0.8 14.4 ± 2.3
70+ 31 18/13 (1.4) 0.7 ± 1.4 23.3 ± 0.8 14.0 ± 2.2
Total 248 127/121 (1.0) −0.7 ± 1.6 23.8 ± 1.0 14.1 ± 2.4
Table 2.
 
Reproducibility of Normal Macular Thickness Measurement Using 3D-OCT
Table 2.
 
Reproducibility of Normal Macular Thickness Measurement Using 3D-OCT
Interobserver (n = 31) Intervisit (n = 48)
Fovea (1 mm) 1.6 ± 0.2 1.7 ± 0.2
Inner ring (3 mm)
    Temporal 0.9 ± 0.1 0.9 ± 0.1
    Superior 1.3 ± 0.1 0.9 ± 0.1
    Nasal 0.9 ± 0.1 1.0 ± 0.1
    Inferior 1.0 ± 0.1 0.9 ± 0.1
Outer ring (6 mm)
    Temporal 1.3 ± 0.1 1.3 ± 0.1
    Superior 1.3 ± 0.1 1.2 ± 0.1
    Nasal 0.7 ± 0.1 1.0 ± 0.1
    Inferior 1.4 ± 0.1 1.3 ± 0.1
Table 3.
 
Sex Difference in Macular Thickness Measurements
Table 3.
 
Sex Difference in Macular Thickness Measurements
Total (n = 248) Men (n = 127) Women (n = 121) P *
Fovea (1 mm) 221.93 ± 18.83(178.32–288.02) 225.58 ± 19.13(178.32–288.02) 218.10 ± 17.79(178.41–272.57) 0.002
Inner ring (3 mm)
    Temporal 284.86 ± 13.96(247.85–334.60) 288.33 ± 14.32(255.99–334.56) 281.22 ± 12.65(247.85–318.42) <0.001
    Superior 296.73 ± 14.51(259.90–340.73) 299.37 ± 15.26(267.94–340.73) 293.96 ± 13.12(259.90–337.12) 0.003
    Nasal 299.22 ± 15.28(263.41–345.77) 301.76 ± 16.68(268.03–345.77) 296.56 ± 13.20(263.41–338.61) 0.007
    Inferior 293.51 ± 14.47(255.90–331.86) 296.43 ± 14.78(259.62–331.86) 290.44 ± 13.54(255.90–329.32) 0.001
Outer ring (6 mm)
    Temporal 243.59 ± 12.26(212.96–280.13) 246.39 ± 11.68(220.02–280.13) 240.65 ± 12.21(212.96–274.76) <0.001
    Superior 257.12 ± 12.87(225.11–297.42) 257.49 ± 12.13(229.88–289.27) 256.73 ± 13.64(225.11–297.42) 0.643
    Nasal 273.44 ± 14.07(236.37–320.17) 273.99 ± 14.01(242.74–309.48) 272.84 ± 14.15(236.37–320.17) 0.522
    Inferior 246.69 ± 13.00(215.29–281.47) 247.74 ± 12.51(215.92–281.46) 245.56 ± 13.43(215.29–276.02) 0.193
Table 4.
 
Partial Correlation between Axial Length and Macular Thickness after Adjustment for Age
Table 4.
 
Partial Correlation between Axial Length and Macular Thickness after Adjustment for Age
P (Adjusted for Age)*
Fovea (1 mm) 0.631
Inner ring (3 mm)
    Temporal 0.600
    Superior 0.714
    Nasal 0.612
    Inferior 0.547
Outer ring (6 mm)
    Temporal 0.088
    Superior 0.536
    Nasal 0.548
    Inferior 0.813
Table 5.
 
Correlation between Age and Macular Thickness with Pearson's Correlation Coefficient and Partial Correlation Coefficient after Adjustment for Axial Length
Table 5.
 
Correlation between Age and Macular Thickness with Pearson's Correlation Coefficient and Partial Correlation Coefficient after Adjustment for Axial Length
Regression (×Age) R 2 P * P (adjusted for AL)†
Fovea (1 mm) 222.26–0.01 0 0.926 0.926
Inner ring (3 mm)
    Temporal 289.77–0.10 0.02 0.054 0.111
    Superior 304.56–0.16 0.04 0.003 0.004
    Nasal 307.53–0.17 0.04 0.003 0.003
    Inferior 299.64–0.13 0.02 0.02 0.053
Outer ring (6 mm)
    Temporal 246.95–0.07 0.01 0.134 0.448
    Superior 265.28–0.17 0.05 <0.001 0.002
    Nasal 284.13–0.22 0.07 <0.001 <0.001
    Inferior 253.42–0.14 0.03 0.004 0.01
Table 6.
 
Correlation between Age and Macular Thickness with Pearson's Correlation Coefficient and Partial Correlation Coefficient after Adjustment for Axial Length in the Men
Table 6.
 
Correlation between Age and Macular Thickness with Pearson's Correlation Coefficient and Partial Correlation Coefficient after Adjustment for Axial Length in the Men
Regression (×Age) R 2 P * P (adjusted for AL)†
Fovea (1 mm) 221.68–0.08 0.01 0.421 0.74
Inner ring (3 mm)
    Temporal 295.13–0.14 0.03 0.06 0.056
    Superior 310.44–0.23 0.07 0.004 0.005
    Nasal 314.96–0.27 0.08 0.001 0.001
    Inferior 306.65–0.21 0.06 0.006 0.018
Outer ring (6 mm)
    Temporal 252.52–0.12 0.03 0.037 0.082
    Superior 269.63–0.25 0.12 <0.001 0.001
    Nasal 289.77–0.32 0.16 <0.001 <0.001
    Inferior 257.88–0.21 0.08 0.001 0.002
Table 7.
 
Correlation between Age and Macular Thickness with Pearson's Correlation Coefficient and Partial Correlation Coefficient after Adjustment for Axial Length in the Women
Table 7.
 
Correlation between Age and Macular Thickness with Pearson's Correlation Coefficient and Partial Correlation Coefficient after Adjustment for Axial Length in the Women
R 2 P * P (adjusted for AL)†
Fovea (1 mm) 0.01 0.229 0.299
Inner ring (3 mm)
    Temporal 0.01 0.31 0.219
    Superior 0.01 0.181 0.059
    Nasal 0.01 0.349 0.149
    Inferior 0 0.564 0.329
Outer ring (6 mm)
    Temporal 0 0.819 0.945
    Superior 0.01 0.295 0.341
    Nasal 0.02 0.172 0.112
    Inferior 0.01 0.383 0.385
Supplementary Table S1
Supplementary Table S2
Supplementary Table S3
Supplementary Figure S1
Supplementary Figure S2
Supplementary Figure S3
Supplementary Figure S4
Supplementary Figure S5
Supplementary Figure S6
Supplementary Figure S7
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