# Incidental detection of retinal nerve fiber layer thinning with slowed progression following optic nerve-carotid artery decompression: A case report

## TL;DR

A patient with retinal nerve fiber layer thinning had slowed progression after surgery to relieve optic nerve compression.

## Contribution

This case report demonstrates a novel clinical observation of slowed retinal nerve fiber layer thinning following optic nerve decompression.

## Key findings

- The rate of retinal nerve fiber layer thinning significantly slowed after optic nerve-carotid artery decompression surgery.
- The patient's predicted blindness was postponed by 10 years following the surgery.

## Abstract

This report aims to present a case of the retinal nerve fiber layer (NFL) thinning, in which the progression of thinning was slowed following optic nerve-carotid artery decompression surgery.

A 41-year-old ophthalmologist incidentally noticed a generalized thinning of NFL in his left eye using optical coherence tomography (OCT). Five years earlier, the OCT showed only mild thinning. While visual acuity and visual fields were normal, the patient reported a blurriness. The MRI revealed an ectatic and tortuous left internal carotid artery compressing the left optic nerve. Due to the lack of reports on the correlation between NFL thickness and visual acuity, an internal review was conducted. We searched for cases with a progression from healthy visual acuity to blindness, and in the only case identified, we investigated the correlation between NFL thickness and visual acuity. Applying this correlation, it was predicted that the patient would lose vision by age 48. As a result, the patient decided to receive decompression surgery. Following the surgery, the rate of NFL thinning significantly slowed from −1.9 μm/year to −0.57 μm/year (p < .0001). At the current age of 48, the patient's corrected visual acuity is 20/16, and visual field remains normal. The predicted onset of blindness has been postponed by 10 years.

We report a case in which compression of the optic nerve by the internal carotid artery was observed in a patient with retinal nerve fiber layer (NFL) thinning. A slowing of NFL thinning was noted following surgical decompression.