Identification of Lesion Components Influencing Visual Function in AMD

Abstract

Abstract: : Purpose: To compare colour fundus photography and fluorescein angiography while exploring the relationships between visual function size, location and composition of the macular lesion in patients with AMD Methods: A standardised visual function assessment (clinical measures of vision) along with colour stereo pair fundus photography was carried out in both eyes of 58 subjects with a confirmed clinical diagnosis of AMD. The size, location and composition of the macular lesion (blood, exudate, sub-retinal fluid, pigment, membrane, atrophy and fibrosis) were measured on the colour photographs using computer-assisted image analysis. 44 subjects also had concurrent fluorescein angiography, classic and occult CNV, blood, blocked fluorescence, fibrosis and the total area of abnormal fluorescence were measured. Multiple linear regression was used to examine the relationship between clinical measures of vision and the location and extent of lesion components identified by both colour and fluorescein image capture. Results: The composition of the macular lesion strongly influenced visual function with atrophy (p = 0.006) and fibrosis (p = 0.001) accounting for most of the variation. When the location of the lesion with respect to the fovea was examined fibrosis within the fovea significantly influenced all clinical measures of vision visual acuity (p = 0.008). The regression model selected the total area of abnormal fluorescence and the composite score of the features measured on colour photography (r₂ =0.47) as the variables that explained most of the variation in clinical measures of vision. Conclusion: The composition and extent of the macular lesion strongly influences visual function in eyes with AMD. Both colour photography and angiography yielded information which together explained considerably more of the variation in the clinical measures of vision than either on its own.

Keywords: 308 age-related macular degeneration • 432 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • 620 visual acuity