Purpose: To examine the genotypes associated with the peripheral retinal phenotypic features in patients with age-related macular degeneration documented with wide-field imaging.
Design: Clinic-based case series study in Croatia. Participants: Using standard protocols, 160 patients \>50 years of age known to have early or advanced AMD and 150 subjects \>50 years of age without known AMD (controls) were studied.
Materials and methods: Both groups of patients were examined with ophthalmoscopy and OCT to confirm their classification. Posterior and peripheral fundus features were documented with Optos wide-field imaging (Optos P200MA, Optos Plc, Dunfermline, Scotland) and graded. DNA was extracted from blood samples and gene polymorphisms were evaluated for complement factor H (CFH) rs1061170 and rs1410996, age-related maculopathy susceptibility (ARMS2) rs10490924, high temperature requirement factor A1 (HtrA1) rs11200638, complement factor B (CFB) rs4151667 and rs641153, complement factor 2 (C2) rs9332739 and rs547154 and complement factor 3 (C3) rs2230199.
The study cohort was identified among the clinical patients at the University Department of Ophthalmology at University Hospital Centre "Sestre milosrdnice", Zagreb, Croatia. The protocol was approved by the Ethics Committee approval (EP-13030/11-13) of the University Hospital Centre "Sestre milosrdnice" and complied with the tenets of the Declaration of Helsinki with the informed consent obtained from all the participants. We included 160 subjects in AMD group and 150 subjects in the control group who met the following criteria: age exceeding 50 years, clinical signs of AMD in at least one eye in AMD group and without signs of the disease in the control group. Exclusion criteria were as follows: confounding maculopathy of any etiology, having a myopic refractive error more than -3.0 diopters in either eye, failure to obtain readable color images documenting at least 270 degrees of the retina (three quadrants), or failure to provide a peripheral blood sample for DNA extraction. All the participants were examined according to standardized examination protocols where the macular region and retinal periphery were photodocumented with Resmax and wide field imaging respectively using the Optos P200MA camera (Optos plc, Dumfermline Scotland).23 Phenotypes Eligibility for the AMD group was determined according to an international classification of AMD.24,25 The retinal periphery was defined as an extramacular area 6000 µm diameter distant from the foveolar centre and a grid template was used for measuring the distance. Following peripheral retinal phenotypes were documented: peripheral drusen, reticular pigmentations (RP), hyperpigmentations (pigment clumping (PC) or nevus (N)), hypopigmentations (peripheral retinal pigment defects (RPD) or atrophic areas (AA)), other degenerations in aggregate (OD) which include any of the following: microcystoid degenerations with degenerative retinoschisis (RD), lattice degenerations (LD), snail-track degeneration (ST), white-without pressure (WWP), paving stone degeneration(also known as cobblestone) (PS), retinal holes (R) and vitreal opacities (VO). The inclusion criteria for the peripheral retinal change was its size which had to exceed at least one hour of the retinal periphery Main outcome measures: The type, localization and frequency of peripheral retinal changes and gene polymorphisms of participants in both groups were examined.
