Abstract

Aim:To study the correlation between intraocular pressure reduction and changes in structural (optic nerve head and nerve fibre layer) and functional (visual fields) parameters in open angle glaucoma patients following trabeculectomy.

Materials and Methods:A prospective, interventional study (n = 40) was done. Patients with COAG between 50 - 80 years with well documented glaucoma progression were included in the study. Patients with unreliable visual fields (fixation loss > 20%, false positive > 15%, and false negative > 33%), OCT images with less than 90% satisfactory A-scan or a signal-to-noise ratio of < 25 dB were excluded. Significant differences in mean test values over 12-months after intervention were evaluated with repeated measure ANOVA (analysis of variance). Logistic regression analysis was performed to study the effect of independent variables (age, gender, IOP reduction, duration of IOP control, change in rim area and rim volume) on dependent variables (RNFL thickness, mean sensitivity and mean deviation, respectively).

Results:Repeated measure ANOVA revealed a significant increase (P < 0.01) in rim area at all time points. There was a significant reduction in IOP at 1-month postoperative followed by slight paradoxical rise at 3 months. Significant changes in RNFL thickness were observed at 3, 6 and 12 months, respectively. On regression analysis, there was structural and functional correlation (IOP and RNFL thickness and rim area and mean deviation). There was 0.4microns change in RNFL thickness for 1mm of IOP reduction. Age (OR = 1.2, 95%CI, 0.89 - 1.34), gender (OR = 3.4, 95%CI, 507- 42.4), change in IOP (OR = 1.9, 95% CI, 1.2 - 32.8) and change in rim area (OR = 2.5, 95%CI, 0.25 - 29) significantly influenced change in RNFL thickness. Change in rim area exhibited higher odds (OR = 2.8) in causing change in mean deviation.

Conclusion:Despite a significant correlation between IOP reduction and RNFL thickness and change in mean deviation and rim area, lowering of IOP by surgical intervention may variably influence structural and functional parameters in glaucoma; these changes may depend on several factors like age, gender, the height and the amount of IOP reduction, the stage of glaucoma and follow up duration.

Keywords:Intraocular Pressure; Optic Nerve Head; Retinal Nerve Fibre Layer Thickness; Regression Analysis Trabeculectomy

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Citation

Citation: Mohan Lal Pandey., et al. “The Correlation Between Intraocular Pressure Reduction and Changes in Optic Nerve Head, Retinal Nerve Fibre Layer and Visual Fields in Open Angle Glaucoma Following Filtration Surgery”.Acta Scientific Ophthalmology 3.1 (2020): 03-08.

Copyright

Copyright: © 2020 Mohan Lal Pandey., et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.