Macular Degeneration is the leading cause of vision loss in the elderly. However, a new study reports that close monitoring those patients with macular degeneration can improve the ability to detect choroidal neovascularization (CNV) while it is still outside the fovea and vision is still good. This can help preserve the vision of those patients diagnosed with macular degeneration for longer periods of time.
Bilateral involvement is common in neovascular or wet macular degeneration, with approximately 10 percent of second eyes developing wet macular degeneration each year through at least the first 5 years after development in the first eye. Wet macular degeneration accounts for approximately 8-10 percent of the diagnosed cases of the eye disease but results in approximately 90 percent of the vision loss. Because of this fact and the fact that wet macular degeneration occurring in the second eye, patients with macular degeneration are often advised to monitor their vision closely. One of the simplest ways of doing this is with an Amsler grid. An amsler grid allows people to detect the earliest symptoms of wet macular degeneration at home.
In the latest study, results of at least 5 years of follow-up data from 1052 participants in the Complications of macular degeneration prevention trial (CAPT) were analyzed. These individuals had bilateral drusen deposits and a visual acuity of 20/40 or better at beginning of the study period. During the study period, patients were examined on an annual basis with a flourescein angiography and retinal photography performed at each visit.
Wet macular degeneration developed in 282 eyes of 225 patients during the follow-up period. Approximately 100 (35 percent) of the cases of macular degeneration were detected between regularly scheduled examinations when patients reported symptoms or their ophthalmologist wanted to see the patient more frequently than annually.
At the time of detection, 192 (68 percent) of the CNV lesions were occult only, 153 (54 percent) were subfoveal, and 157 (56 percent) were less than or equal to 2 disc areas in size. Visual acuity was 20/40 or better in 123 (69 percent) of 179 eyes with visual acuity measured at the time of detection. choroidal neovacularization (CNV) developed in both eyes in 57 patients (25 percent) during CAPT follow-up.
The investigators conclude that when patients are monitored closely, many CNV lesions can be detected outside of the fovea and when they are relatively small. Early detection may lead to improved long-term visual acuity and better treatment for the patients.
The study authors have indicated that “close monitoring of high-risk eyes, such as fellow eyes in patients with unilateral CNV or eyes with multiple large drusen and pigmentary changes, can lead to detection of CNV when it is more likely to be outside the fovea, relatively small, and without a large loss in visual acuity. Regular retinal examinations, optical coherence tomography, preferential hyperacuity perimetry, and use of the Amsler grid may aid in early detection of CNV.”
In conclusion, many eyes with CNV in this study were detected before the loss of substantial visual acuity. Regular monitoring of high-risk patients may allow early detection and treatment that may result in long-term preservation of visual acuity.
Ophthalmology. 2008 Sep;115(9):1468-73, 1473.e1-2. Epub 2008 May 16.