Abstract
Purpose :
To investigate the relationship between L-cone-specific temporal contrast sensitivity (L-cone tCS) and established functional and structural outcome parameters in Stargardt’s disease (STGD).
Methods :
Twelve patients (5F, 24±14yrs) with confirmed STGD were included. L-cone-isolating temporal modulation was created in a 12° test field using a four-primary LED stimulator using triple silent substitution. L-cone tCS was defined as 1 / L-cone contrast at threshold. Mean deviation of tCS was calculated by 1) subtracting the logarithm of the observed tCS from age-correlated normal values, 2) converting to decibel and 3) averaging the 12, 16, and 20Hz results.
Clinical parameters were: mean deviation of static white-on-white perimetry in the central 12° (MD12), area of hyporeflectivity (AoH) in infrared scanning-laser-ophthalmoscopy scans, and best corrected visual acuity (logMAR).
Principal component analysis (PCA) was performed to identify associations between outcome parameters and to subdivide patients into different clusters. Pearson correlation coefficients were calculated for confirming associations found in PCA.
Results :
In the PCA 2D plot, three clinically meaningful clusters were identified: 1) fundus flavimaculatus without central defect (FF; good logMAR, good MD12), 2) bull’s-eye maculopathy (BEM; good logMAR and reduced MD12), and 3) central defect and eccentric fixation (CD; both logMAR and MD12 reduced). Interestingly, one patient, who was located between the CD cluster and the BEM clusters, showed signs of BEM in the OCT but seemed to have lost central fixation recently. In our cohort, L-cone tCS deviation was inversely correlated to AoH (R=-0.63; p=0.03) and positively correlated to MD12deg (R=0.74; p=0.01).
Conclusions :
PCA can be useful to explore phenotypes, when clinical outcomes are intercorrelated. Close association between MD and L-cone tCS is not surprising, because stimulus detection in white-on-white perimetry is also dominated by L-cones. As a consequence, tCS did not provide additional information that might change clustering. However, tCS can be measured faster than perimetric MD and might be used as a surrogate in patients who cannot perform static perimetry.
This is a 2021 ARVO Annual Meeting abstract.