Abstract
Purpose:
RMD, also known as reticular pseudodrusen, may demonstrate “target” lesions, or central hyperreflectant areas within the characteristic hyporeflectant reticular lesions in infrared (IR) images.1 The dynamics of these target lesions were studied and compared to those of RMD itself.
Methods:
We retrospectively identified 54 patients (54 eyes) from a single institution (L’Hôpital Intercommunal de Créteil, France) who had RMD in one eye and late-stage AMD in the fellow eye visible on IR imaging. Additional inclusion criteria included ≥ 2 visits with IR imaging and ≥ 1 year of follow-up. Five patients were excluded due to poor image quality. Target lesions on the remaining 49 images were identified and counted by two graders independently and to consensus. To exclude larger lesions that may be soft drusen, we limited our definition of hyperreflectant targets to reticular lesions with clearly defined hyporeflectant borders.
Results:
The subjects had a mean age at baseline of 82±6, 65% (32/49) of whom were female. The mean duration of follow-up was 25 months. Hyperreflectant targets were identified within the reticular pattern of 41/49 subjects (84%). For subjects who had visible target lesions, the mean number within the 56.25 mm2 (7.5 mm x 7.5 mm) IR window at baseline was 10±14 targets. In this subset there was an average absolute change in overall target number of 7±8 targets per 56.25 mm2/year. For 46% of these subjects (19/41), the target number increased at later follow up by an average of 7±8 lesions. In 49% of these subjects (20/41), the targets decreased by 10±9. Two eyes remained unchanged. In all subjects of this cohort, target lesions were clustered around the macula (within the 3000 micron diameter circle).
Conclusions:
RMD in AMD is known to be a dynamic process associated with a high risk of progression to advanced AMD.2 The substructure of the target lesions themselves, like all of RMD, is uncertain, and has been ascribed to some aspect of subretinal deposits1 or to deeper reflectant lesions. They appear and disappear as shown herein independently of the RMD lesions themselves, and their central predilection is at variance with RMD in general, which is found most often at the superior arcades. These observations may provide clues for further research on this disease. 1.Querques et al.(2011)Retina;31:518-26, 2.Arnold et al.(1995)Retina;15:183-91
Keywords: 412 age-related macular degeneration •
550 imaging/image analysis: clinical