Growth Rates of Choroidal Neovascularization in Age–Related Macular Degeneration

Abstract

Abstract: : Purpose: To determine growth rates of choroidal neovascularization (CNV) in patients with age–related macular degeneration (ARMD). Methods: A retrospective chart review was performed for twelve patients evaluated at Emory University with classical type 2 CNV who were followed as controls in the macular photocoagulation study (MPS) between 1986 –1992. Fluorescein angiograms (FA) of eligible subjects were digitized using a Nikon LS–2000 slide scanner and the Nikon Scan software. The growth rates were determined by analyzing the relative growth in each patient using Adobe Photoshop and SCION Image for Windows based on NIH ImageJ analysis software. Growth parameters were greatest diameter change, distance of proximal edges to optic disc and fovea compared to disc diameter (DD) as well as total CNV area compared to disc area (DA). These results were compared to previous human studies by Vander et al Ophthalmology 1989; 96: 1422–1429 and Singerman et al Ophthalmology 1989; 96: 1426–1429. The human CNV growth rates were also compared to growth rates in an animal CNV model. Results: Since the axial length was not assessed in the study growth rates could only be measured as relative values to the optic disc in each patient. The greatest diameter growth in the human CNV membrane was on average 0.04 DD per month or 1.41 DD during a mean 38 month FU. During the same time the mean distance from the CNV to the optic nerve was reduced by 1.03 DD (0.03 DD per month). The mean CNV membrane area increased by 7.48 DA at FU or 0.2 DA per month. The CNV was situated underneath the fovea on the first visit in 75 % of the patients. Conclusions:Comparison of natural CNV growth rates in humans and animals could prove valuable in interpreting clinical and experimental therapeutic results in ARMD.

Keywords: choroid: neovascularization • clinical (human) or epidemiologic studies: natural history • imaging/image analysis: clinical