Structural and Functional Correlation of Retinal Photoreceptors Overlying Lesions in White Dot Syndrome

Abstract

 

Purpose

 

Lesions in white dot syndromes (WDS) may be associated with photoreceptor (PR) loss. A prospective cohort study was performed to evaluate PR density and correlate it with retinal sensitivity overlying lesions in WDS.

 

Methods

 

Lesions of WDS (≤ 3 chosen/eye), within 5° foveal eccentricity, were imaged using adaptive optics (AO) (rxt1, Imagine Eyes, France), spectral-domain optical coherence tomography (SD-OCT) and fundus autofluorescence (FAF) (Heidelberg Spectralis®, Germany). In this study, lesions were defined as active if there were presence of hyper-autofluorescence within the lesions. Eyes with choroidal neovascularization, high myopia (> 6 diopters), media opacity and other concomitant diseases were excluded. PR density was calculated using manufacturer-provided AO Detect 1.0 software after adjustment for axial length using IOLMaster® (Zeiss Meditech, CA). Retinal sensitivity was assessed using microperimetry (MP) (Optos SLO, UK) and correlated with PR density using Spearman Rank Correlation test.

 

Results

 

Twenty-six lesions (9 patients: 7 females, mean age of 54.9 ± 16.6 years; 16 eyes) were analyzed. Diagnoses included serpiginous choroiditis (2 eyes), birdshot choroidopathy (3 eyes), presumed ocular histoplasmosis syndrome (2 eyes), punctate inner choroidopathy (6 eyes) and multifocal choroiditis (4 eyes). Mean PR density overlying 8 active lesions was 3076 ± 4654.89 cones/mm² and 6943.5 ± 5739.51 cones/mm² overlying 18 inactive lesions (p = 0.117). Mean PR density over 20 lesions with disrupted inner segment-outer segment (IS-OS) junction on SD-OCT was 5005.64 ± 5024.89 cones/mm² and 6943.5 ± 5739.51 cones/mm² over 6 lesions with intact IS-OS junction (p = 0.28). Mean retinal sensitivity (7.42 ± 4.70 dB) showed fair correlation with PR density (ρ = 0.43, p = 0.04). Mean retinal sensitivity over lesions with intact IS-OS junction was 13 ± 2.45 dB and 5.71 ± 4.16 dB over lesions with disrupted IS-OS junction (p = 0.007). Appearance of lesions on AO imaging is shown in figure.

 

Conclusions

 

AO imaging may allow high-resolution analysis of PR loss among lesions in WDS. Such microstructural changes may correlate with functional loss.  

 

Image shows an active lesion on FAF (A) associated with focal hypo-intensities on AO imaging (yellow asterisks) suggestive of PR loss (B). Healed lesions (C) show circumferential hypo-intense halo (white arrowheads) surrounding area of scarring (D).