Abstract
Purpose:
Patients with macular disease regularly experience and report metamorphopsia (visual distortion), yet the prevalence and variation of this symptom has not yet been reported. Amsler grids are commonly used to screen for metamorphopsia, but a large sample of these reported distortions has not been reviewed. We analyzed Amsler grids to estimate the prevalence and magnitude of metamorphopsia across macular disease subtypes.
Methods:
We analyzed ophthalmologic records from 5,661 retina patients and 7,110 monocular Amsler grids from patients with Wet AMD, Dry AMD, Epiretinal membrane (ERM), Central Serous Retinopathy (CSR), choroidal macular edema (CME) or Diabetic Macular Edema (DME). Patients indicated distortions on 16° x 16° digital Amsler grids. A convex hull around the distortion was calculated to represent the area of distortion, and the centroid of this polygon was used to indicate the location of distortion.
Results:
Patients with Wet AMD had a significantly higher probability of reporting distortion than patients with Dry AMD (p = 0.002), CSR (p = 0.03), or ERM (p=0.003). The average change in the area or location of distortion between repeated grid assessments was not significantly different from zero across all disease groups (average of five grids per patient and a maximum of 30 repeats). Distortions were concentrated around central vision, particularly for Wet AMD patients (p < 0.001), but were more uniformly distributed for DME patients. N-1 cross validation showed that the spatial patterns of distortion were systematic and non-random, but were similar across diagnoses. Poor acuity was significantly correlated with larger distortions in the Wet AMD, Dry AMD, and ERM groups (p < 0.05).
Conclusions:
Visual distortions reported on Amsler grids are repeatable and their spatial locations systematically vary across the visual field and among different subtypes of macular disease. These patterns provide statistical data that may be used to assist in the management of macular disease.
Keywords: 584 low vision •
585 macula/fovea •
713 shape, form, contour, object perception