BACKGROUND: Visual acuity is commonly used as a functional outcome measure in patients with age-related macular degeneration (AMD), despite having a weak correlation with self-perceived visual quality of life. Microperimetry is a useful method of detecting loss of macular function. We wanted to investigate the relationship between these two objective visual outcome measures and subjective vision-related quality of life, finding out which objective measure is more patient-relevant.
METHODS: Fifty-one consecutive patients with AMD were recruited to the study. Participants were required to complete the Visual Function Questionnaire 39, the Early Treatment Diabetic Retinopathy Study visual acuity examination and a microperimetry assessment using the Micro Perimeter 3. One patient withdrew consent and seven patients dropped out due to cooperation difficulties under microperimetry. Forty-three patients with AMD were included in the study: twenty-eight patients with late AMD (exudative AMD) and fifteen patients with early (non-exudative) AMD. The right eye was included as standard, as was the eye with the best-corrected visual acuity.
RESULTS: There was a higher correlation between vision-related quality of life and macular sensitivity (r = 0.458; p = 0.014) than between vision-related quality of life and visual acuity (r = 0.446; p = 0.018) in patients with late AMD. There was a positive correlation between vision-related quality of life and macular sensitivity in patients with early AMD (r = 0.542; p = 0.037) while the correlation between vision-related quality of life and visual acuity in these patients was not statistically significant. Composite score (r = 0.469; p = 0.012) correlated highest with the nasal outer macular sub-region and near-distance activities score (r = 0.652; p < 0.001) correlated highest with the nasal inner macular sub-region in patients with late AMD. Correlations between composite score and macular sub-regions in patients with early AMD were not significant, but near-distance activities score correlated with the nasal outer macular sub-region in these patients (r = 0.469; p = 0.012).
CONCLUSIONS: Macular sensitivity as measured using microperimetry correlates with vision-related quality of life in early AMD and in late AMD, showing it to be a patient-relevant outcome measure. Furthermore, the nasal sub-regions of the macula appear to be preferred retinal loci in patients with AMD. (338 words).