Abstract
Purpose :
Retinitis pigmentosa(RP) is an inherited retinal degenerative disease, including various genotypes and phenotypes, but all includes progressive retinal degeneration of different retinal layers over time. However, it has not been examined whether the structure of the macular fundus shape change during degeneration of RP. Recent development of using curvatures maps created from OCT has enhanced our possibilities to follow curvature change during the progression of RP.
Methods :
107 patients (female 58%,male 42%), mean age at baseline at endline (45.6±16.19 and 49.0±16,20) were diagnosed with RP based on clinical appearance and electrophysiology results, were retrospectively reviewed. All patients were evaluated with OCT( Spectralis, Heidelberg Engineering, Germany) at least 2 times within a period of minimum 1 year to maximum 7 years. OCT images from all patients, were futher analyzed to create curvature maps of macula. From vertical and horizontal OCT scans, with fovea at the center, the Bruch’s membrane line was plotted every 200 micrometer. From the marked points the approximate curve of Bruch’s membrane was calculated and we analyzed the mean macular curvature of Bruch’s membrane in 6 mm range as mean macular curvature index (MMCI)(figure 1). We compared the MMCI from OCT images obtained at baseline and at endline. Besides OCT images, refractive error were evaluated. Linear mixed models were used to follow these changes.
Results :
Macular curvature changed significantly vertically but was rather unchanged horizontally.Vertical macular curvature mean changed from -15.7 x10-5(1/μm)at baseline to -16.4 x10-5(1/μm) at endpoint (p value <0,0393) and horizontal curvature -14.4 x10-5(1/μm) at baseline to -14.7 x10-5(1/μm) at endline (p value =0,480). Refractive error did not change significantly in the Rp patients,those who had undergone cataract surgery during the follow up period were excluded.
Conclusions :
The degeneration of neurosensory retina could have an influence on the macular curvature especially in the vertical direction. The change of the macular curvature in horizontal direction might be prevented by the existence of the optic disc. Our results also indicated that the progression of the curvature did not seem to be related to the progression of myopia. Current study added a new structural information about curvature changes in RP patients.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.