Abstract
Purpose :
Retinal degeneration associated with mutations in the male germ cell associated kinase (MAK) gene is associated with preservation of the nasal visual field and foveal vision, although cystoid macular edema (CME) and intraretinal cystoid spaces (ICS) can occur which can reduce visual acuity. We sought to describe the characteristics of MAK-related retinal degeneration using optical coherence tomography angiography (OCT-A) and adaptive optics scanning laser ophthalmoscopy (AOSLO).
Methods :
In this study, 3 patients with rod-cone degeneration underwent genetic testing which revealed disease-causing mutations in the MAK gene. Patients were clinically evaluated, observing visual acuity, kinetic perimetry, SD-OCT, OCT-A and AOSLO. We compared the foveal avascular zone (FAZ) area, vessel densities (VD) of the superficial capillary plexus (SCP), deep capillary plexus (DCP) and choriocapillaris (CC) in the central macula from OCTA images in all 3 patients, and the cone spacing of one patient from AOSLO images, with data from 3 age-similar normal subjects.
Results :
The patients were 25, 56 and 81 years old. The visual acuity was 20/20-20/32 in two of the patients, and 20/60- 20/70 in the 56 year old patient with severe CME. Kinetic visual field tests showed relatively preserved nasal fields in all patients until advanced stages of disease. Although the FAZ area and DVP density were not significantly different from normal (P = 0.64 and 0.54, respectively), the SVP density and CC density were significantly lower in patients (P = 0.004 and 0.016, respectively, Hotelling’s T2) compared to normal subjects. Cone photoreceptor spacing was at the upper limits of normal at all locations where cones were unambiguously identified despite ICS in the youngest patient.
Conclusions :
Vascular density was significantly reduced in the SCP and CC compared to age-similar normal subjects, but FAZ area, DVP density and cone spacing were not significantly different from normal subjects. Atrophic changes of the retinal pigment epithelium during disease progression may cause reduction of VD in the choriocapillaris. Reduced vessel density in the superficial retinal vessels around the fovea may contribute to CME and ICS, which can cause reduced visual acuity in patients with MAK-related retinal degeneration.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.