Structural imaging with en face OCT smay be an effective alternative to red-free fundus photography for identifying progressive retinal nerve fiber layer (RNFL) defects in glaucoma patients, researchers from Korea University College of Medicine report.

Their study, published in the Journal of Glaucoma, found a strong topographic correlation between the two methods and even in eyes with progressive glaucoma.

The researchers compared the progression of localized RNFL defects in red-free fundus photographs, en face structural images and OCT-angiography (OCT-A) images.

The study included 45 glaucomatous eyes that showed RNFL defect widening in red-free photography, described as a “red-free defect” in the study. The wedge-shaped hypo-reflective area radiating from the optic nerve head in the en face OCT and OCT-A images was termed “en face defect” and “OCT-A defect,” respectively.

When comparing the baseline angular parameters, the study found no significant differences between the red-free defect and the en face defect, or between the red-free defect and the OCT-A defect.

The follow-up angular parameters also showed no difference between the red-free defect and the en face defect. However, the OCT-A defect showed significantly greater values compared with the red-free defect and en face defect with respect to the distal angular location and angular width during the follow-up visit (36.78±15.10 vs. 34.10±15.09 vs. 33.40±15.05 degrees).

Ji MJ, Park JH, Yoo C, Kim YY. Comparison of the progression of localized retinal nerve fiber layer defects in red-free fundus photograph, en face structural image, and OCT angiography image. Journal of Glaucoma. May 8, 2020. [Epub ahead of print].