Abstract
Purpose: :
To study structure-function relationship in the macular area using spectral-domain optical coherence tomography (SD-OCT) and standard automated perimetry (SAP) in normal eyes.
Methods: :
The subjects were 79 normal eyes of 79 subjects (35 females/44 males; 50.1±15.5 yrs.) who underwent ophthalmic examinations and SAP with Humphery Perimeter 24-2 SITA-Standard program (Carl Zeiss Meditec, Inc., Dublin, CA) to confirm absence of any ocular abnormalities. Three-dimensional data in a 6.0 mmx6.0 mm area centered on the optic nerve head (ONH) and fovea were obtained with a Topcon 3D OCT-1000 (Version 3.20, Topcon Inc., Tokyo, Japan) after pharmacological mydriasis 3 times each with several-second intervals and the best quality scans (quality factor ≥ 60%, without misalignment, influences by involuntary blinking or saccade, or segmentation failure) were adopted. Correlation between the mean sensitivity (dB) of the 12 most central visual field (VF) test points and Log[mean circum-papillary retinal nerve fiber layer thickness along the 3.4 mm diameter-circle centered on the barycenter of the ONH (cpRNFLT) of the temporal 90° sector (Garway-Heath et al. Ophthalmology 2000;107:1809-15)], Log[mean macular RNFLT (mRNFLT)], Log[mean macular ganglion cell layer thickness (mGCLT), Log[sum of mGCLT and mean inner plexiform layer (IPL) thickness (mGCL+T)] and Log[sum of mRNFLT and mGCL+T (mGCCT)] were calculated.
Results: :
The mean (SD) of refraction, mean deviation, mean sensitivity of the central 12 points, mean temporal 90° cpRNFLT, mRNFLT, mGCLT, mGCL+T, and mGCCT was -0.41(1.44) diopters, -0.43(1.20) dB, 32.0(1.5) dB, 77.9(10.2), 35.4(3.4), 39.2(3.0), 71.8(4.4), and 107.2(7.2) μm, respectively. Pearson's correlation coefficient between VF sensitivity and structural measures were 0.103 (P>0.3) for mean temporal 90° cpRNFLT, 0.282 (P=0.012) for mRNFLT, 0.419 (P<0.001) for GCL, 0.408 (P<0.001) for GCL+T, and 0.388 (P<0.001) for GCCT, respectively.
Conclusions: :
Correlation of VF sensitivity to each macular inner layer thickness, especially GCL, was significant in normal eyes, while that to cpRNFLT was weak as previously reported, suggesting that macular GCL is better suited for studying structure-function relationship in human eyes and may be more sensitive to the earlier glaucomatous change than cpRNFLT.
Keywords: ganglion cells • macula/fovea • imaging/image analysis: clinical