SD-OCT Features and Macular Sensitivity in ABCA4-related Stargardt disease (STGD1)

Abstract

Purpose : To assess the association between structural parameters on SD-OCT and macular function measured by microperimetry in STGD1.

Methods : Baseline data from the multicenter natural history ProgStar-study of STGD1 were analyzed. From SD-OCT images the study reading center measured the thickness of the inner retina (IR), outer nuclear layer (ONL), inner and outer segments (IS, OS) and RPE thicknesses in the ETDRS central subfield (CS), inner ring (INR) and outer ring (OR). Macular sensitivity (MS) was assessed at 68 loci in the central 20° using the Nidek MP-1 device, and average sensitivities by ETDRS subfield were categorized as absolute scotoma (0dB), relative scotoma (<12dB), or relatively normal (≥12dB). Generalized logistic regressions estimated structure-function relationships.

Results : Of the 198 patients analyzed (324 eyes where their MS were centered at the fovea), 58% were female, 88% were white, with median age 23 years. 53% had absolute scotoma (average MS=0) in the central subfield, 15% in inner ring, and 1% in outer ring. In the central subfield, 39%, 84%, and 83% of eyes had complete loss of RPE, OS, and IS, respectively. Multiple regression including thickness of all layers estimated complete loss of (IS+OS) thickness was associated with 62.5 higher odds of absolute scotoma versus relatively normal sensitivity (95%CI:10 - 409, p<0.001). In the inner ring, thinner (IS+OS) and RPE was associated with higher odds of absolute scotoma versus relatively normal sensitivity (odds ratio: 5.7(p=0.007), 1.2(p=0.002), respectively). In the outer ring, every 1 µm thinner (IS+OS) was associated with 1.7 (p<0.001) higher odds of relative scotoma versus relatively normal sensitivity. Figure 1 shows absolute scotoma corresponded to thinner RPE, IS, OS and ONL. Complete loss of photoreceptor IS+OS in the central subfield was strongly associated with foveal absolute scotoma. In the inner ring, both photoreceptor and RPE thicknesses correlated with absolute scotoma. In the outer ring, the absolute scotoma subgroup demonstrates increased inner retina thickness.

Conclusions : When developing therapeutic molecules or approaches to treat Stargardt disease, it is necessary to evaluate the effect of the potential therapy on preserving both RPE and photoreceptors.

This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.

 

Figure 1 Heatmap Representation of Layer Thickness Variation Across Sensitivity Categories by Layer and Subfield