Optical coherence tomographic assessment of retinal nerve fiber layer thickness changes before and after glaucoma filtration surgery

Abstract

Background: Glaucomatous Optic Neuropathy (GON) is very common in the glaucoma patients, and impaired effect of glaucoma is measured by the Retinal Nerve Fiber Layer (RNFL) thickness.Objective: The study was conducted to find out the mean RNFL thickness, RNFL thickness in different quadrants, Intra-Ocular Pressure (IOP) changes, and visual field changes after filtration surgery in different ages and genders using Optical Coherence Tomography (OCT).Materials and Methods:The study was an interventional case-series conducted at the Glaucoma Clinic at the Regional Institute of Ophthalmology at Kolkata from March 2009 to August 2010. Fifty-one eyes of 43 open angle glaucoma patients had been selected for clinical and ophthalmologic evaluation. All the eyes of glaucoma patients who fulfilled the inclusion criteria were registered in the study population. The glaucoma filtration surgery was done in these patients. The RNFL thickness, IOP, visual field changes were measured before and after intervention of filtration surgery. Pre-operative OCT images of RNFL were obtained 0 to 120 days before surgery, and post-operative images were obtained from 60 to 120 days after surgery. Data collected in a standard data collection form included schedule.Results: Paired t-test was used. RNFL thickness was (pre-operative: 52.56 ± 17.40, post-operative: 58.48 ± 20.20, P < 0.0001) significantly increased after filtration surgery measured by OCT with significant reduction of IOP (r = - 0.38, P = 0.005) irrespective of age and gender.Conclusions: An increase in RNFL thickness was observed after glaucoma filtration surgery that correlated with IOP reduction.

Relationship between preoperative high intraocular pressure and retinal nerve fibre layer thinning after glaucoma surgery

“…The mean preoperative IOPs reported by Sarkar et al . 15 and Rebolleda et al . 17 were 26.9 ± 6.4 mmHg and 23.6 ± 5.1 mmHg, respectively.…”

“…It is therefore possible that the amount of RNFL thinning measured in the present study (5.4 µm) was not detected in the previous study. Second, the preoperative IOPs of the enrolled patients differed 10,13–15,17 . In subgroup analyses based on preoperative peak IOPs, there was significant RNFL thinning, and the higher the preoperative peak IOP, the greater the postoperative RNFL thinning in patients with a preoperative peak IOP ≥ 37 mmHg (median value).…”

“…Chang and Grajewski reported paradoxical RNFL thinning after cupping reversal following trabeculotomy 11 . By contrast, some studies have shown a significant increase in RNFL thickness following IOP-lowering surgery, or treatment with IOP-lowering agents 12–15 . However, some other studies have reported no RNFL thickness change upon lowering IOP 10,16,17 .…”

The Effect of Glaucoma Filtration Surgery on Structural and Functional Eye Parameters in a Short-Term Study

“…Conflicting results have been reported regarding improvement in the postoperative RNFL thickness. Several studies have reported a significant change in RNFL thickness following IOP reduction (Aydin et al, 2003;Sarkar et al, 2014). Similarly, the study of Chang et al found a significant increase in RNFL, but with no correlation with IOP (Chang et al, 2007).…”

Influence of Primary Open Angle Glaucoma Surgery on Structural and Functional Parameters of the Optic Nerve and Its Association with the Level of Atrial Natriuretic Peptide. Summary of the Doctoral Thesis

“…In practice and clinical trials, reduction of intraocular pressure by a surgical method has been shown to affect the rate of progression of glaucoma(Bertrand et al, 2014). Surgical treatment may improve structural(Sarkar et al, 2014;Irak et al, 1996) and functional parameters of the eye(Bertrand et al, 2014).…”