# Normal-Tension Glaucoma Complicated by a Giant Internal Carotid-Ophthalmic Artery Aneurysm

## TL;DR

A patient with normal tension glaucoma had worsening vision due to a giant artery aneurysm, highlighting the need to consider neurological causes in atypical cases.

## Contribution

This case report highlights a rare complication of normal tension glaucoma caused by a giant internal carotid-ophthalmic artery aneurysm.

## Key findings

- A 72-year-old woman with normal tension glaucoma showed accelerated vision loss linked to an unruptured giant aneurysm.
- Following aneurysm treatment, the patient continued to show progressive visual field loss and retinal nerve fiber layer thinning.
- The case emphasizes the importance of neurological evaluation in glaucoma patients with atypical vision deterioration.

## Abstract

Purpose. We describe a patient with normal tension glaucoma (NTG) of several years whose management was complicated by the presence of a giant internal carotid-ophthalmic artery aneurysm. Observations. A 72-year-old woman presented to our glaucoma clinic with accelerated deterioration of her vision in her left eye (OS) over a 1-month period. Her ophthalmic history was most notable for bilateral NTG diagnosed 3 years prior which had been treated with several laser trabeculoplasty OS and topical bimatoprost 0.01% eye drops in both eyes (OU). Upon evaluation, her visual acuity OS had worsened, and visual field (VF) testing showed extensive progressive losses temporally and pericentrally OS over a year with stable IOP measurements and no neurological complaints. Given her atypical NTG progression, she was referred for an urgent neurological evaluation which revealed an unruptured giant left internal carotid-ophthalmic aneurysm. Following the successful treatment of the aneurysm with platinum coils, she continued to demonstrate additional bilateral ophthalmic changes including further progression of VF loss and RNFL thinning OS > OD on follow-up. Conclusion and Importance. Overall, this report describes a unique complication in the management of a patient with chronic bilateral NTG in the form of a giant internal carotid-ophthalmic aneurysm. Moreover, it highlights the need for clinicians to maintain a degree of suspicion for compressive lesions of the optic nerve when presented with atypical progression of VFs and/or visual acuity loss in glaucomatous patients.