Geographic atrophy (GA) in dry AMD patients often eventually leads to vision loss in millions of people, and there is not yet a proven method of preventing or treating its progression. However, many studies are currently underway researching promising treatment methods to help increase understanding of GA.
A study recently dove into the topic of long-term enlargement of GA to understand the natural course of how the condition progresses and contribute to the knowledge needed to eventually devise a cure. Researchers gathered data spanning from 1990 to 2015 from the Rotterdam Study cohorts 1, 2, and 3 and the Blue Mountains Eye Study and included a total of 171 participants (62% female). Results found that, on average, the younger participants had smaller areas of GA, and the older the person, the larger the affected eye area. 41% of participants also had bilateral GA.
The mean enlargement rate of the total 242 observed eyes was 1.09 mm2 per year. Those with incident GA had a slightly lower rate than those with prevalent GA (1.03 vs. 1.16 mm2 per year). Between the different cohorts in the study, enlargement rates ranged from 0.53 to 1.28mm per year.
A total of 37% of the newly diagnosed GA patients already had foveal involvement at the time of diagnosis. Within five years for most of the eyes (60.4%), GA reached the central fovea. The average time it took for central foveal involvement to occur following a GA diagnosis was 5.6 years, and for all of the eyes, it took anywhere from three to 12. “Eyes with central foveal involvement had severe visual impairment (BCVA less than 20/200) and blindness (BCVA less than 20/400) significantly more often than eyes without central or perifoveal involvement,” the researchers wrote in their paper.
Researchers also evaluated the life expectancy of study participants to determine how long after a GA diagnosis people live, and moreover, how much time is left to treat and monitor the AMD patient in the late stage of the condition. The mean life expectancy was found to be 6.4 years after initial presentation of GA, and 90 was the mean age at death. Because so many GA patients already have initial atrophy in the fovea or will likely develop it within five years, there is currently not much hope for preventing or reversing vision loss following some diagnoses.
Studies like these emphasize the urgent need for treatment development for those with GA. Nearly half the patients lost functional vision by the time of their death. It’s crucial to prioritize any available treatments in the five-year mean time window before foveal involvement when steady or rapid vision loss will become inevitable.
Colijn JM, Liefers B, Joachim M, et al. Enlargement of geographic atrophy from first diagnosis to end of life. JAMA Ophthalmology. May 20, 2021. [Epub ahead of print.]