Longitudinal assessment of retinal layer thickness changes and corresponding functional loss in eyes with Autoimmune Retinopathy

Abstract

Purpose : To analyze thickness changes of retinal layers and their association with functional loss [as measured by electroretinogram (ERG) and best-corrected visual acuity (BCVA)] in eyes with autoimmune retinopathy (AIR) using spectral-domain optical coherence tomography (SD-OCT).

Methods : Heidelberg Spectralis® device was utilized to obtain SD-OCT raster scans of 9 eyes from 5 patients diagnosed with AIR (confirmed by presence of serum auto-retinal antibodies). Heidelberg Heyex™ 5.2 software was used to segment retinal layers along a 5mm horizontal scan passing through the fovea. Retinal layers analyzed include full retinal thickness (FRT), retinal pigment epithelium (RPE), photoreceptor layer (PRL), inner nuclear layer (INL), combined ganglion cell and inner plexiform layers (GCL+), nerve fiber layer (NFL), and combined GCL+ and NFL layers (GCL+/NFL). Changes in thickness of the layers were assessed in 0.5mm increments along the B-scan in the nasal and temporal regions. Recorded values were compared to corresponding values of 51 eyes from 51 subjects with no known ocular pathology. Values were correlated to BCVA and ERG findings, if available, at each respective visit.

Results : Data from five AIR patients (9 eyes) under care of the same physician were analyzed. Mean and median ages of our subjects were 60.2 (range: 33 to 83) and 60 years at baseline, respectively; 3 patients were male (60%). Among the 51 controls, mean and median ages were 51.5 (range: 40 to 75) and 51, respectively; 26 were males (51%). Average length of follow-up period for eyes with AIR was 22.4 months (range: 9.7 to 50.6). OCT images 9 to 11 months’ (Visit 1) post-baseline were analyzed. Further, OCT images of 3 patients (5 eyes) 17 to 19 months’ (Visit 2) post-baseline were analyzed. Consistent, progressive decrease in thicknesses was observed in all retinal layers except RPE (that showed thickening). Mean BCVA change from baseline to visit 1 and 2 was improvement of approx. 8.1 and 8.8 ETDRS letters, respectively. ERG findings showed a functional deficit that correlated with structural loss.

Conclusions : Progressive thinning of retinal layers occurs over time in all studied layers, with the exception of RPE, which normalized in thickness. Despite retinal losses, BCVA slightly improved in studied patients, suggesting that therapy may have value in improving visual acuity in AIR patients.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.

 

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