Challenges in Glaucoma Management in High Myopia After Refractive Surgery: A Case Report

TL;DR

This case report discusses the challenges of managing glaucoma in a highly myopic patient with a history of refractive surgery and corneal abnormalities.

Contribution

The paper highlights the limitations of standard IOP measurement techniques and the effectiveness of micropulse laser in such complex cases.

Findings

Goldmann applanation tonometry showed unreliable IOP readings in the eye with corneal scarring and a Ferrara ring.

Micropulse transscleral cyclophotocoagulation reduced IOP and slowed structural and functional progression.

Corneal-independent tonometry and functional monitoring are emphasized for accurate glaucoma management in post-refractive patients.

Abstract

Managing glaucoma in highly myopic patients who have had prior refractive surgery is particularly complex. The altered corneal biomechanics in these eyes interfere with standard intraocular pressure (IOP) assessment, making conventional measurement less reliable. This report presents a 52-year-old male athlete with high myopia, who underwent radial keratotomy 25 years ago and evolved to iatrogenic ectasia on the OD (right eye), treated with intra-stromal ring implantation. Several years later, he underwent bilateral cataract surgery, followed by laser retinopexy and vitrectomy for sequential retinal detachment. Goldmann applanation tonometry (GAT) showed a stable mean of 15 mmHg in the OS (left eye), whereas readings in the OD varied widely, from 18 to 50 mmHg, depending on the applanation site, likely due to corneal scarring and the presence of the Ferrara ring. IOP measured with Corvis ST remained elevated in both eyes (29 mmHg OD and 28 mmHg OS). OCT revealed retinal nerve fiber layer (RNFL) thinning, and a visual field defect was also documented with the central 10-2 Humprey Field Analyzer with the 10-2 protocol and SITA-Standard strategy. Despite long-term treatment, clinical control was insufficient, as progression was documented on 10-2 visual fields, symptom deterioration, and biomechanical evidence suggesting sustained IOP-related damage, even where numerical values were inconsistent. We therefore performed two sessions of micropulse transscleral cyclophotocoagulation. This intervention led to a moderate reduction in IOP and appeared to slow the progression of both structural and functional changes. This report highlights the limitations of GAT in eyes with a history of refractive surgery, particularly radial keratotomy, as well as in ectatic disorders and patients with Ferrara’s ring implantation. It also emphasizes the value of corneal-independent methods for tonometry combined with functional monitoring. In situations where surgical intervention is either not the most appropriate indication or cannot be feasibly performed, micropulse laser offers a viable and effective alternative. Individualized glaucoma management remains essential in post-refractive, myopic patients with structurally abnormal eyes.

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