New research published in Ophthalmology and Therapy outlined a potential new age-related macular degeneration (AMD) phenotype with subclinical angioid streaks (AS).
Talk about the study.
In this retrospective, observational study, investigators identified patients with AMD who showed signs of AS on structural optical coherence tomography (OCT), but not on fundus examination.
The OCT features of AS that were examined included Bruch’s membrane (BM) breaks and large BM dehiscences.
Findings?
Within the AMD patient cohort—among 543 eyes of 274 patients (mean age 82)— 73 eyes of 46 patients (mean age 81) showed these features on OCT that were not visible on fundus examination.
The estimated prevalence of subclinical age-related AS was 13.4% (95% confidence interval [CI] 10.3-16.3%) in this AMD population.
Go on…
Of note, 53 eyes (73%) with AS features were affected by peripapillary atrophy, often with a “petaloid-like” pattern, similar to typical characteristics of diseases associated with AS.
Were drusen observed?
The research team observed that multiple patients in the AS cohort had drusen findings, including:
- Reticular pseudodrusen (RPD): 97%
- With drusen: 41%
- Without drusen: 59%
Meaning…
This demonstrates a significant difference in the prevalence of RPD in eyes with subclinical AS compared to AMD eyes without subclinical AS.
What about the AMD stage?
Interestingly, of the 73 subclinical AS cases, 71 were affected by late AMD—57 with macular neovascularization and 14 with geographic atrophy (GA).
Significance?
This finding indicates a higher rate of advanced AMD stage in subclinical AS eyes compared to AMD eyes without subclinical AS.
Anything else?
Investigators noted BM breaks in 100% of cases and BM dehiscences in 37%.
Expert opinion?
Per the study authors, the “petaloid-like” pattern of atrophy seen in AMD patients with subclinical AS was also described in a previous study as a typical pattern of atrophy in AS patients secondary to pseudoxanthoma elasticum (PXE).
“Due to the similar BM alterations and peripapillary involvement of subclinical AS in AMD, we suggest the predominant involvement of BM as a driving factor of this phenotype,” the authors stated.
How does this impact treatment approaches?
Due to the fact that BM likely plays a significant role in subclinical AS etiology, therapeutical approaches may need to differ from those for regular AMD patients.
“In particular, anti-complement treatments may not be as effective in this group of patients as in other drusen-driven ‘classic’ AMD phenotypes,” the authors explained.
Take home.
Subclinical AS in eyes with AMD is a relatively frequent and peculiar phenotype of the disease, with characteristics that suggest a primary involvement of BM and clinical similarities to mild, late-onset PXE.
AMD patients with subclinical AS have a different clinical presentation, imaging features, and pathogenesis—distinguishing them as a distinct group within the AMD population.