Reticular pseudodrusen predicts late-stage AMD

By Lucy Piper, Senior medwireNews Reporter

Reticular pseudodrusen (RPD) increases the likelihood of people with choroidal neovascularisation (CNV) in one eye also developing late-stage, age-related macular degeneration (AMD) in the other eye, researchers report.

They found that it increased the risk of progression to geographic atrophy (GA), specifically, and exacerbated the increased risk of CNV associated with the presence of drusen of 125 µm or more and pigmentary changes.

“Our findings have implications for monitoring and counseling high-risk patients with RPD, who will require close follow-up”, the team writes in Ophthalmology.

Two hundred patients with CNV secondary to AMD in one eye and no signs of late-stage AMD in the other eye participated in the trial. The average age of the patients was 77 years and they were receiving anti-vascular endothelial growth factor treatment.

At baseline, 58% of the patients had RPD, 68% had drusen of 125 µm or more and 36% had pigmentary changes in the unaffected eye, as detected using spectral-domain optical coherence tomography, near-infrared reflectance and colour fundus photography.

After a mean follow-up of 2.3 years, progression to CNV occurred in 36% of unaffected eyes while progression to GA was evident in 14%.

The presence of late-stage AMD was more likely to occur if patients had RPD at baseline, at a rate of 61.0% versus 33.4% among patients without RPD. This was mainly due to a higher occurrence of GA, at 22.4% versus 2.4%.

Indeed, the presence of RPD was found to be an independent risk factor for the development of GA, at a hazard ratio (HR) of 4.93, but not for CNV (HR=1.19).

The onset of GA also occurred sooner in patients with RPD than in those without, at an average of 4.54 years versus 7.11 years, whereas there was no difference in the time to CNV onset.

The researchers, led by Robert Finger (University of Melbourne, Victoria, Australia), note that both drusen of 125 µm or more and pigmentary changes were also significant risk factors for the development of GA and for CNV, with the greatest risk seen in patients with all three macular risk factors.

“With the ubiquity of [optical coherence tomography], which usually includes infrared imaging, clinicians should keep RPD at the forefront of their minds, when discussing patients’ prognosis and the risk of late-stage disease developing in fellow second eyes”, conclude Finger and co-workers.

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