Abstract
Purpose :
Limited literature exists on Optic Nerve Head Drusen (ONHD) progression. Thought to be benign, ONHD are globules of mucoproteins and mucopolysaccharides that progressively calcify in the optic disc. Found in 2-3% of the population, ONHD can be categorized as superficial, buried, or surface pearl (the most severe). Pearl type progress superficially and may exert mechanical stress on the surrounding vasculature, resulting in peripheral vision loss over time (1.6% per year on VF) due to thinning of the retinal nerve fiber layer (RNFL) and ganglion cell complex (GCC), similar to glaucoma.
Methods :
Non-mydriatic 45-degree color and fundus autofluorescence (FAF) were captured and grayscale reflectance histograms were determined using PhotoshopTM V7. Lipofuscin concentrations in overall ONH as well as targeted single ONHD were measured. Visual Field (VF) was assessed via 30-2 central threshold tests. GCC and RNFL thickness were assessed using Ocular Coherence Tomography (OCT-B). Subject 1 is a 24 y/o female with early signs of pearl ONHD who was followed from 2020 to 2021. Subject 2 is a 53 y/o female with 40 years advanced pearl ONHD with documented FAF and progressive VF loss.
Results :
After 14 months, subject 1 Rt FAF intensity index value showed an 11% increase in FAF reflectance (37 to 41) (Fig 1A), while Lt value increased by 89% (37 to 70) (Fig 1B) mirroring the progression seen on OCT-B as the drusen rises to the surface (Fig 1C). Subject 1 had minor increased peripheral VF defects Rt but overall stable VF indices in both eyes. Subject 2 had significant peripheral VF loss Rt/Lt over 40 years with an overall ONHD FAF intensity index value of 96 and a single ONHD intensity index value was 170 FAF reflectance on the surface of the ONH. (Fig 2)
Conclusions :
Our findings suggest that over time, pearl ONHD rise superficially to the most anterior portion of the optic disc (Fig 1C). This is shown by an increase in FAF fluorescence of subject 1 Lt, measured by a novel approach of grayscale reflectance quantification. Noninvasive FAF may be a more sensitive marker of early ONHD progression than OCT or VF (Fig 1D) and can be used to screen patients for ONHD. As there is no cure, early detection and protective management of intraocular pressures may be warranted. Further studies will include OCT-B with 1080 nm enhanced depth imaging and 3D volumetric imaging.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.