A new study by New York Eye and the Ear Infirmary of Mount Sinai illustrated that two different types of deposits in the retina, drusen and subretinal drusenoid deposits (SDDs) could contribute to early age-related macular degeneration (AMD). (via)
Tell me about the study.
Investigators measured the fundus autofluorescence (FAF) and evaluated spectral-domain optical coherence tomography (SD-OCT) scans in 18 patients (32 eyes) with advanced AMD and geographic atrophy (GA) to determine if the presence of drusen and SDDs were markers for advanced AMD progression.
As GA can occur across multiple regions of the retina, researchers analyzed 52 GA regions overall.
Who qualified for the study?
Qualifying participants had to have SD-OCT scans from the past 3 years to allow researchers to determine whether the diseased regions started with drusen, SDDs, or both.
What did they find?
Researchers discovered that, of the 52 analyzed diseased regions, 18 were from drusen, 12 were from SDDs, and 22 were from mixtures of drusen and SDDs.
FAF measured twice as bright in patients with SDDs compared to those with drusen. Subjects with SDDs had brightness readings that averaged 72; subjects with drusen had readings that averaged 36; and subjects with both drusen and SDDs had mixed values.
Let’s dissect this.
While the formation and progression of drusen can be slowed with vitamin supplements to prevent vision loss, SDDs currently have no existing treatments.
These findings, paired with previous research, provide conclusive evidence of two distinct disease processes that occur in patients with AMD. One results in darker fluorescence and drusen, while the other presents with brighter fluorescence and SDDs.
What does it mean?
This suggests that SDDs likely result from deficient blood flow to the eye caused by cardiovascular disease.
R. Theodore Smith, MD, PhD, lead author of the study, recommended that further studies should be done on women and marginalized populations where there are higher rates of undetected heart disease.
Take home?
Patients who present with SDDs should be made aware of the correlation between SDDs and life-threatening undetected heart conditions. It is vital for ECPs to diagnose early on whether an AMD patient has drusen, SDDs, or both, to determine the course of treatment and prevent further progression.
Depending on the case presentation, ECPs can consider referral to retina specialists, when warranted.
Taking it one collaborative step further, referral to a cardiologist could be useful, as treating the comorbid cardiovascular disease might aid in restoring the eye’s blood supply to treat SDDs.