Abstract
Purpose :
The shift of fixation in patient with macular degeneration may impair visual acuity (VA) and daily life. The aim of this study is to assess correlation between fixation shift in microperimetry and visual function in patients with macular dystrophy (MD).
Methods :
Nineteen patients (age 24-76, mean 56.7 ± 12.2 years) with MD, including 14 females and 5 males, were enrolled in this retrospective study. One eye from each patient with a better VA was analyzed. Fixation shift (FS), defined as the direction and distance between location of fovea and preferred retinal locus (PRL), was determined by superposition of images of microperimetry-1 (MP-1) and spectral domain optical coherence tomography (SD-OCT). The alignment of MP-1 and SD-OCT images based on vascular landmarks was conducted with Photoshop. Pearson’s correlation test (r) was used for analyzing the correlations of parameters.
Results :
The mean sensitivity (MS) in MP-1 was 8.94 ± 6.18 dB, and the best corrected visual acuity (BCVA) ranged from 20/800 to 20/20. FS was observed in 14 (73.7%) patients, mostly to the supero-nasal quadrant of macula (11/14, 78.5%), and two patients presenting inferior FS had low percentage of fixation points within 2 degree in MP-1 (32 - 33%) and poor BCVA (20/800 - 20/200). Five eyes without FS presented BCVA 20/25 to 20/20 while MS ranging from 1.4 to 17.8 dB. The mean distance of FS was 1080 ± 818 micrometers in patient with FS. The distance of FS was correlated to the logarithm of the minimum angle of resolution (logMAR) VA (r = 0.765, P = 0.001), and the percentage of fixation points within 2 degree in MP-1 (r = -0.586, P = 0.027), but not correlated to MS in MP-1 (r = -0.151, P = 0.606). The percentage of fixation location in MP-1 was correlated to the distance of FS (r = -0.521, P = 0.022), and the central macular thickness in SD-OCT (r = 0.673, P= 0.008). Superimposed fovea and PRL was observed if the ellipsoid zone in fovea was spared without complete degeneration in SD-OCT.
Conclusions :
The presenting VA is correlated to FS in MD patients. The MS in MP-1 may be reduced before VA and FS deteriorates when MD progresses, and the percentage of fixation location in MP-1 significantly correlates with FS. When compared to VA and SD-OCT, MP-1 could be more sensitive to macular dysfunction when fovea is preserved anatomically, and suitable for early detection of the disease progression.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.