One year dynamic changes of retinal nerve fibre layer thickness after acute attack in primary angle closure glaucoma

Objective To detect the dynamic changes of retinal nerve fibre layer (RNFL) thickness in different period after attack of primary acute angle closure glaucoma (PAACG). Design Prospective case series. Participants 35 eyes (35 cases) with first attack of diagnosed PAACG in Department of Ophthalmology of Xuanwu Hospital, were enrolled from 2007-2009. Methods 35 patients with unilateral attack of PAACG who had all resolved after initial treatment were enrolled. Using Stratus OCT3, RNFL changes in both eyes were scanned by the time of two weeks, 3 months, 6 months and 12 months after the first attack. Differences between affected eyes and fellow eyes for the mean RNFL thickness at various periods were compared. Correlation between RNFL thickness and attacking intraocular pressure (IOP) was also analyzed. Main Outcome Measures Retinal nerve fibre layer thickness. Results The average thickness of RNFL in affected eyes after two weeks was significantly thicker than that in fellow eyes: (141.85±25.22) μm vs.(112.95±10.54)μm (P= 0.000). After 3 months, the difference was no longer significant (112.38±16.15)μm, vs. (112.26±16.04)μm (P=0.966). The average thickness of RNFL in affected eyes was significantly thinner than in the fellow eyes (101.22±14.06) μm vs. (108.65±15.03)μm (P=0.021) at the end of 6 months, and after 12 months (92.29±13.05)μm vs. (106.77± 14.90) μm (P=0.000). RNFL thickness was thinning gradually in affected eyes (F=51.48, P=0.000) than that in fellow eyes (F=1.599, P=0.192) during one year observation. The higher the attacking IOP, the thicker the RNFL would be within 3 months (r=0.692, P=0.000). However, no association was demonstrated between the final RNFL thinning and the attacking IOP (r=0.242, P=0.081) after 12 months. Conclusions RNFL thickness was found to be thinning after long period of acute attack in PAACG with controlled IOP. Attacking IOP was not the only important factor which resulted in damage of RNFL in affected eyes. RNFL thickness in fellow eyes was also found to change without significance. The clinical significance needs further studies. glaucoma, angle closure; intraocular pressure; retina nerve fibre layer; optical coherence tomography.