Fixation Stability and Preferred Retinal Locus in Advanced Age-Related Macular Degeneration

Abstract

Objectives:To evaluate fixation stability and characteristics of the preferred retinal locus (PRL) in patients with advanced age-related macular degeneration (AMD).Materials and Methods:Sixty-three eyes of 63 patients with AMD who presented to the low vision unit were included in this prospective study. Sociodemographic characteristics, eye examination findings, and reading performance results with the Minnesota Low Vision Reading test were evaluated. Microperimetry was used to evaluate fixation stability and PRL characteristics.Results:There was unstable fixation in 68% of the eyes, relative stable fixation in 27%, and stable fixation in 5%. The mean PRL-foveal distance was 5.15°±3.31° (range 0.75°-14.2°). PRL-foveal distance was greater in cases with unstable fixation than cases with stable fixation (p=0.023). Distance of the PRL from the lesion margin was not associated with absolute scotoma size or fixation stability (p=0.315, p=0.095, respectively). PRLs were most frequently located in the nasal quadrant (31%), followed by the superior quadrant (26%) of the retina. There was no significant relationship between PRL location and fixation stability (p=0.088). Fixation stability was significantly associated with reading speed (p=0.003).Conclusion:In advanced AMD, PRL-foveal distance is an important factor in fixation stability. Knowing the factors that affect fixation stability may be important in determining low vision rehabilitation strategies for these patients because of the strong association between fixation stability and reading speed.

Keywords

• low vision rehabilitation
• fixation stability
• microperimetry
• preferred retinal locus
• age-related macular degeneration