Factors associated with retinal nerve fibre layer stability after glaucoma surgery

Abstract

Aims/Purpose: The first objective of the present study was to investigate whether retinal nerve fibre layer (RNFL) deterioration exists after successful glaucoma surgery, and how long it lasts. The second objective was to identify the factors associated with RNFL thickness stability after surgery.Methods: A retrospective observational study was conducted. A total of 128 eyes of 108 patients who received one successful glaucoma surgery including trabeculectomy and Ahmed valve implantation, and had been followed up with cirrus optical coherence tomography (cOCT) were examined. We defined intraocular pressure (IOP) reduction as the difference between peak IOP before surgery and IOP at the first cOCT examination after surgery. RNFL thickness reduction greater than −5.03 μm/year immediately after surgery, but remained below −5.03 μm/year in two or more consecutive examinations was defined as a ‘maintenance after progression group’ (group1). Also, the other group was defined as a ‘maintenance group’ (group 2), RNFL thickness reduction less than −5.03 μm/year.Results: There was no significant difference between two groups in sex, age, diagnosis, and operation. However, preoperative IOP was statistically significantly higher in group 2 than in group 1 (p = 0.039). There was no significant difference between group 1 and 2 in the duration of IOP elevation before surgery (p = 0.998). The preoperative RNFL thickness tended to be thicker in group 2 than in group 1, but it was not statistically significant. The average duration of progression in group 2 was 23.9 months. Factors containing age, sex, operation, diagnosis, preoperative IOP, preoperative IOP rise duration, and pretreatment RNFL thickness were less relevant with postoperative RNFL thickness reduction stabilization.Conclusions: In conclusion, the factor that showed a significant difference between the ‘maintenance after progression group’ (group 1) and the ‘maintenance group’ (group 2) was preoperative IOP.ReferencesKim WJ, Kim KN, Sung JY, Kim JY, Kim CS. Relationship between preoperative high intraocular pressure and retinal nerve fibre layer thinning after glaucoma surgery. Sci Rep‐Uk 2019, 9.