Abstract

Aims: To demonstrate ultrahigh resolution, three-dimensional optical coherence tomography (3D-OCT) and projection OCT fundus imaging for enhanced visualization of outer retinal pathology in non-exudative age related macular degeneration (AMD).

Methods: A high-speed, ultrahigh 3.5 μm resolution OCT prototype instrument was developed for the ophthalmic clinic. 83 patients with non-exudative AMD were imaged. Projection OCT fundus images were generated from 3D-OCT data by selectively summing different retinal depth levels. Results were compared with standard ophthalmic examination, including fundus photography and fluorescein angiography, when indicated.

Results: Projection OCT fundus imaging enhanced the visualization of outer retinal pathology in non-exudative AMD. Different types of drusen exhibited distinct features in projection OCT images. Photoreceptor disruption was indicated by loss of the photoreceptor inner/outer segment (IS/OS) boundary and external limiting membrane (ELM). RPE atrophy can be assessed using choroid level projection OCT images.

Conclusions: Projection OCT fundus imaging facilities rapid interpretation of large 3D OCT data sets. Projection OCT enhances contrast and visualizes outer retinal pathology not visible with standard fundus imaging or OCT fundus imaging. Projection OCT fundus images enable registration with standard ophthalmic diagnostics and cross-sectional OCT images. Outer retinal alterations can be assessed and drusen morphology, photoreceptor impairment, and pigmentary abnormalities identified.