Analysis of normal tension glaucoma with thin cornea using optical coherence tomography

Abstract

Objective To investigate the thickness changes of peripapillary retinal nerve fiber layer (RNFL) in normal tension glaucoma (NTG) with thin cornea measured by optical coherence tomography (OCT).Methods Twenty-one NTG patients (42 eyes) with thin cornea were divided into two groups according to their central corneal thickness (CCT):group 1 (480μm≤CCT＜500μm) and group 2 (460μm≤CCT＜480μm),and analysis the different results of OCT scan and visual outcome in two groups.Results There were no significant differences in OCT parameters of Avg.,Thick,Savg,Iavg,Navg and Tavg among the two groups (P ＞0.05),while Max-Min was lower in group 2 (P ＜0.05);There were also no significant differences in the optic nerve head analysis results,visual field mean defect (MD) and mean sensitivity (MS) among two groups (P＞0.05).The average RNFL thickness and MD showed a strong and negative linear relationship(r =-0.602,P =0.000).Conclusions OCT can make quantitative measurement and analysis of optic disc and RNFL for NTG patients,and has a good correlation with vision field.It has important significance in the early diagnosis of NTG.For NTG patients with thin corneas,there is no significant correlation between the level of CCT and extent of retinal nerve fiber layer defect. Key words: Normal tension glaucoma; Optical coherence tomography; Central corneal thickness