OCT Shows Thicker Retinal Layers Are Associated With Better Contrast Sensitivity

Better contrast sensitivity (CS) is associated with greater retinal nerve fiber layer (RNFL) and macular ganglion cell complex (GCC) thicknesses for healthy adults aged 80 years or older, according to research published in JAMA Ophthalmology. The investigation reviewed normative optical coherence tomography (OCT) and OCT angiography (OCT-A) measures. and their associations with visual function.

Participants included 759 participants (mean age 80±4.2 years, 63% women) culled from the Atherosclerosis Risk in Communities Study from Jackson, Mississippi (all self-reported Black ethnicity), and Washington County, Maryland (all self-reported White ethnicity). The participants were recruited into the Eye Determinants of Cognition (EyeDOC) study, of which a subset were included in the new study’s analysis.

The researchers collected the patients’ retinal measurements, including RNFL thickness, macular GCC thickness, macular vessel density (VD) in the superficial capillary plexus (SCP) and deep capillary plexus (DCP), and foveal avascular zone (FAZ) area with spectral-domain OCT and OCT-A. They also evaluated visual function, including presenting distance vision, corrected distance vision, near visual acuity (VA), and contrast sensitivity (CS).

The researchers report that participants of Jackson and Washington County demonstrated differences in mean GCC thickness (89.2±9.3 μm vs 92.3±8.5 μm) and mean FAZ (0.36±0.16 mm² vs 0.26±0.12 mm², respectively). 

Compared with participants aged older than 80 years, the team found that those aged 80 years or younger had greater mean RNFL thickness and mean VD in SCP and DCP (RNFL: ≤80 years, 93.2±10.5 μm; >80 years, 91.1±11.6 μm; VD SCP: ≤80 years, 44.3%±3.5%; >80 years, 43.5%±3.8%; VD DCP: ≤80 years, 44.7%±4.9%; >80 years, 43.7%±4.8%). 

With linear regression analysis, the researchers demonstrated that each 10 μm increment in RNFL thickness and GCC thickness was positively associated with 0.016 higher logarithm of the contrast sensitivity among all participants (RNFL: 95% confidence interval [CI], 0.005-0.027; P =.004; GCC: 95% CI, 0.003-0.029; P =.02). They found associations of VA and structural measures only in participants of Jackson County, with coefficients per 10 μm increment of 0.012 logMAR VA (RNFL: 95% CI, 0.000-0.023; P =.049) and 0.020 logMAR VA (GCC: 95% CI, 0.004-0.034; P =.04).

“These findings suggest that clinical application of normative references for OCT- and OCT-A-based measures should consider demographic and community features,” researchers explain. Additionally, the research shows that contrast sensitivity is a more sensitive marker of retinal neuronal differences than visual acuity.

Limitations of the study included lack of design to assess causal associations or directions of effect, a manual image-grading process, adjustment for multiple testing on 95% CIs, and an analysis of OCT and OCT-A measures by imaging sector or quadrant.

Disclosure: One study author declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.  

Reference

Dong Y, Guo X, Arsiwala-Scheppach LT, et al. Association of optical coherence tomography and optical coherence tomography angiography retinal features with visual function in older adults. JAMA Ophthalmol. Published online July 14, 2022. doi:10.1001/jamaophthalmol.2022.2099