Author:
Kempf Melanie,Kohl Susanne,Stingl Krunoslav,Nasser Fadi,Stingl Katarina,Kortuem Friederike C.
Abstract
PurposeTo determine the structure of the cone photoreceptor mosaic in the macula in eyes with retinitis pigmentosa related to Usher syndrome using adaptive optics fundus (AO) imaging and to correlate these findings with those of the standard clinical diagnostics.MethodsTen patients with a genetically confirmed retinitis pigmentosa in Usher syndrome due to biallelic variants in MYO7A or USH2A were enrolled in the study. All patients underwent a complete ophthalmological examination including best corrected visual acuity (BCVA), spectral-domain optical coherence tomography (SD-OCT) with fundus autofluorescence photography (FAF), full-field (ffERG) and multifocal electroretinography (mfERG) and Adaptive Optics Flood Illuminated Ophthalmoscopy (AO, rtx1™, Imagine Eyes, Orsay, France). The cone density was assessed centrally and at each 0.5 degree horizontally and vertically from 1–4 degree of eccentricity.ResultsIn the AO images, photoreceptor cell death was visualized as a disruption of the cone mosaic and low cone density. In the early stage of the disease, cones were still visible in the fovea, whereas outside the fovea a loss of cones was recognizable by blurry, dark patches. The blurry patches corresponded to the parafoveal hypofluorescent ring in the FAF images and the beginning loss of the IS/OS line and external limiting membrane in the SD-OCT images. FfERGs were non-recordable in 7 patients and reduced in 3. The mfERG was reduced in all patients and correlated significantly (p <0.001) with the cone density. The kinetic visual field area, measured with III4e and I4e, did not correlate with the cone density.ConclusionThe structure of the photoreceptors in Usher syndrome patients were detectable by AO fundus imaging. The approach of using high-resolution technique to assess the photoreceptor structure complements the established clinical examinations and allows a more sensitive monitoring of early stages of retinitis pigmentosa in Usher syndrome.
Reference41 articles.
1. Clinical and molecular genetics of Usher syndrome;Kimberling;J Am Acad Audiol,1995
2. The prevalence of Usher syndrome and other retinal dystrophy-hearing impairment associations;Rosenberg;Clin Genet,1997
3. Exceptionelles Verhalten des Gesichtsfeldes bei Pigmententartungen der Netzhaut;Von Graefe;Von Graefe’s Arch Klin Exp Ophthalmol,1858
4. Clinical features of X linked juvenile retinoschisis in Chinese families associated with novel mutations in the RS1 gene;Li;Mol Vis,2007
5. New clinical and molecular evidence linking mutations in ARSG to Usher syndrome type IV;Peter;Hum Mutat,2021