Longitudinal changes in outer nuclear layer thickness in soft drusen and reticular pseudodrusen

Area of Science:

• Ophthalmology
• Retinal Diseases
• Macular Degeneration

Background:

• Drusen are characteristic of early and intermediate age-related macular degeneration (AMD).
• Outer nuclear layer (ONL) thickness is a key indicator of retinal health.
• Understanding ONL changes in different drusen types is crucial for AMD progression insights.

Purpose of the Study:

• To compare outer nuclear layer thickness between soft drusen and reticular pseudodrusen.
• To assess the rate of ONL thinning in these distinct drusen types over two years.
• To correlate structural ONL changes with potential functional deficits in AMD.

Main Methods:

• Retrospective observational study of patients over 50 with soft drusen or reticular pseudodrusen.
• Utilized fundus photography, infrared imaging, fundus autofluorescence, and spectral domain optical coherence tomography (SD-OCT).
• Measured ONL thickness across nine Early Treatment Diabetic Retinopathy Study (ETDRS) subfields and analyzed thinning rates using generalized estimating equations.

Main Results:

• Analyzed data from 17 eyes with soft drusen and 9 eyes with reticular pseudodrusen.
• Significantly greater ONL thinning observed in reticular pseudodrusen compared to soft drusen, particularly in superior and nasal subfields.
• ONL was 5-12 μm thinner in reticular pseudodrusen eyes, with a faster thinning rate in the outer superior subfield.

Conclusions:

• ONL thickness is consistently lower in reticular pseudodrusen compared to soft drusen.
• These structural differences in ONL thickness may underlie functional vision impairments in reticular pseudodrusen.
• Further research can explore the direct link between ONL thinning and visual function in AMD subtypes.