Fixation Patterns In Microperimetry Of Patients With Treatment-Naïve Neovascular AMD

Abstract

Purpose: : To evaluate fixation patterns of patients with native neovascular AMD tracked during microperimetric examination and to show relations to visual acuity and morphological integrity assessed in SD-OCT.

Methods: : 32 eyes of 32 patients with native neovascular AMD have been investigated. The best-corrected distance visual acuity was assessed using ETDRS charts. Additionally, microperimetric examination (NIDEK microperimeter MP1) and SD-OCT (Heidelberg Spectralis OCT) have been performed. The OCT B-scans were used to locate the foveal region on the en-face image. The external limiting membrane (ELM) integrity and the inner segment/outer segment (IS/OS) interface integrity in the foveal region was evaluated on the OCT B-scans. Further, the mapped en-face images of the OCT and microperimetric fundus images showing the fixation record were overlayed and analyzed. Datasets without sufficient image quality to perfom the overlay were excluded (n=5).

Results: : Mean patient age was 79.2 years (SD ± 9.1) and mean VA in ETDRS test was 54.3 (SD ± 11.9) letters. Patients with intact ELM in the foveal region (n = 12) fixated in 62.3% of the examination time within a 2° field and in 90,3% within a 4° field, while patients showing discontinued ELM (n = 15) showed in 42.9% fixation within a 2° field and in 80,5% within a 4° field. The differences between the morphological groups were significant (p < 0.03 in 2° and p < 0.04 in 4°). Patients with intact IS/OS (n = 2) showed in 55.5% fixation within a 2° field and in 91.5% within a 4° field, while patients with impaired IS/OS (n=23) integrity showed in 52.5% fixation within a 2° field and in 84.8% within a 4° field. The correlation coefficient between VA and fixation is calculated as 0.21 (p = 0.3) in 2° and 0.29 (p = 0.15) in 4°.

Conclusions: : An association between morphological alterations and fixation stability was found. The impairment of the ELM integrity is capable of predicting the fixation stability. In the present cohort, the number of patients with intact IS/OS was insufficient to investigate possible relations to fixation. There was no significant correlation found between visual acuity and fixation patterns whatsoever.

Keywords: age-related macular degeneration • perimetry • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)