Saccade Latencies are Longer for Early/Intermediate AMD than Age-Matched Normal Patients.

Abstract

Purpose : Previous literature has shown that fixation stability and reading performance is poor in patients with advanced stages of age-related macular degeneration (AMD). However, little research has been conducted to determine oculomotor characteristics in patients with early/intermediate AMD. The aim of this study was to determine saccade latency differences between early/intermediate AMD patients and age-matched controls.

Methods : Thirteen subjects with early/intermediate AMD (age 75.1 ± 10.29) and fourteen age-matched controls (age 70.5 ± 6.42, p = 0.18) were enrolled in the study. All participants underwent a clinical comprehensive eye examination including refraction, best corrected visual acuity, optical coherence tomography, color fundus photography, and fundus autofluorescence photos. The logMAR visual acuities were 0.03 ± 0.105 and -0.007 ± 0.119 for the AMD and control patients, respectively (p = 0.35). The simplified AREDS scale was used to classify the AMD patients (2.5 ± 1.17). Saccade latency was obtained utilizing the screen-based Tobii TX300 eye tracker (Tobii Technology, Sweden) to determine eye position. Testing procedures were conducted monocularly. The stimulus for testing was an “X” subtending 2 degrees vertically and horizontally. Initially, the cross appeared in the center of the display. The cross was displayed for 30 seconds before the stimulus was removed and an identical cross was displaced 5 degrees horizontal to the right or left of the initial cross. The second cross was displayed for 30 seconds and then removed. Saccade latency was defined as the time in milliseconds between when the cross moved and the subject’s first saccade to the new cross location. The average saccade latency was determined for five forward (i.e., to the right) and backward saccades (i.e., to the left).

Results : Saccade latency was statistically increased for early/intermediate AMD (326.1 ± 91.6) compared to age-matched controls (252.3 ± 80.3) for forward saccades (two-tailed t-test, T₂₅ = 2.229, p = 0.035) but not backward saccades (AMD 299.2 ± 95.7, Control 293.1 ± 164.7, p = 0.37).

Conclusions : Forward saccade latency was significantly greater for early/intermediate AMD subjects compared to age-matched controls. This increase in saccade latency for early/intermediate AMD patients may account for their increase in reading complaints.

This is a 2021 ARVO Annual Meeting abstract.