Abstract
Purpose :
The presence of lacquer cracks in highly myopic eyes with myopic macular degeneration (MMD) disrupts the blood retinal barrier and exposes antigens from the otherwise immune-privileged retina. The formation of retinal autoantibodies to these antigens may be involved in the retinal pigment epithelium (RPE) atrophy seen in severe forms of MMD. The aim of this study is to evaluate the prevalence of retinal autoantibodies in patients with high myopia.
Methods :
This is a clinic-based series of 16 patients with high myopia (spherical equivalent ≤-6 diopters or axial length≥26.5mm) recruited from Singapore National Eye Centre’s high myopia clinic. MMD was graded from fundus photographs according to the META-PM Classification. Presence of MMD was defined as META-PM category ≥ 2. Axial length (AL) and logMAR best corrected visual acuity (BCVA) were measured. Sera were obtained from subjects and analysed for the presence of RAA with the Western blot technique. The main outcome measure was the number of RAA in cases compared to controls.
Results :
The mean age was 51.1±3.0 years, mean AL was 30.0±2.33mm, logMAR BCVA was 0.38±0.32 and 12 (75%) were female. At least 1 retinal autoantibody was detected in all patients and the median number of retinal autoantibodies was 4.5 (range 1-7). The most common retinal autoantibody overall was anti-carbonic anhydrase II (anti-CAII, 30kDa), present in 9 patients (56.3%), followed by anti-aldolase C (40kDa) in 7 patients (43.8%) and anti-a enolase (46kDa) in 7 patients (43.8%). Anti-CAII was detected in more patients with MMD than those without but this difference was not statistically significant (75% vs 37.5%, p=0.32). Logmar BCVA was also worse in subjects with anti-CAII (0.5±0.38 vs 0.22±0.08, p=0.06). The mean number of retinal autoantibodies was not significantly different between patients with or without MMD (5.0±1.3 vs 4.0±1.9 respectively, p=0.23). Number of retinal autoantibodies was significantly correlated with AL (r=0.61, p=0.012).
Conclusions :
Retinal autoantibodies are prevalent among patients with high myopia and increases with increasing axial length. In particular, anti CAII antibodies were highly prevalent in patients with MMD, suggesting that they may be involved in the pathogenicity of MMD. Further studies are necessary to confirm these observations in larger cohorts.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.