Abstract
Purpose :
The goal of this study is to evaluate how retinal thickness varies across the central 56 degrees comparing the two eyes in anisomyopia.
Methods :
Subjects were n=19 young adults (n=38 eyes, SE refractive error -0.13D to -11.38D, mean: -4.50±2.80D, AL 22.27 to 29.42 mm, mean: 25.17±1.64 mm) with anisomyopia, defined as a difference in SE of 1.00D or more (average SE difference: 1.79±1.01D). Retinal thickness was measured using OCT (Optovue RTVue). To evaluate the retina across the central 56deg, OCT measurements were taken three times: (1) while subjects fixated at a center target, (2) +18deg, and (3) -18deg eccentricity. Using the full retinal thickness data provided by the RTVue software, for a total of 3,060 scan values, we analyzed the following dimensions: (1) Foveal Pit thickness, defined as the thinnest point within the foveola (average 20 points); (2) Nasal and Temporal Foveal Shoulder thickness, defined as the thickest value nasal and temporal to the fovea (average of 20 points each); (3) Temporal Retina, defined as slope and intercept of the area 10 to 28deg temporal to the fovea; and (4) Nasal Retina, defined as the average thickness of the nasal retina from (70 points past) the optic nerve head and up to 28deg eccentricity. Central and peripheral axial length measurements were taken using a LenStar LS900 (Haag Streit) on-axis, and at ± 30, 20, 16, 12, 8, and 4 degrees horizontally (average central AL difference: 0.68±0.41mm). Pearson Correlation statistical tests and two-sample t-tests were performed using RStudio.
Results :
Central axial length was not correlated with Foveal Pit thickness (p=0.086, R2=0.080), but longer eyes showed a thinner Nasal Foveal Shoulder (p=0.040, R2=0.112). A thinner nasal foveal shoulder was also correlated with longer AL at that location (p=0.045, R2=0.160). Longer central axial lengths were correlated with thinner temporal retinas at 28deg eccentricity (p=0.001, R2=0.259) and thinner retinas in the region nasal to the ONH (p<0.001, R2=0.328). No differences in retinal thickness were found between the more and less myopic eyes in anisomyopia (Foveal Pit: t=-0.02, p=0.98; Nasal Shoulder of the foveal pit: t=0.06, p=0.98; Temporal Slope Intercept: t=0.08, p=0.94; or Nasal Retina thickness: t=-0.60, p=0.55).
Conclusions :
Retinal thickness is associated with the individual length of the eyes, not with the differences between more and less myopic eyes in anisomyopia.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.