Rate of central corneal thickness changes in primary angle closure eyes: long-term follow-up results.

Background: Central corneal thickness (CCT) and its association with intraocular pressure, which is a pivotal parameter in glaucoma management, has previously been reported. In this study, we intended to investigate the long-term change of CCT in terms of rate in eyes with primary angle-closure (PAC). Additionally, we aimed to analyze events that could affect CCT.

Methods: In this retrospective study, 26 patients with PAC who had a follow-up period of more than 5 years were analyzed. The rate of CCT changes from baseline was evaluated from the serial CCT measurements over the average follow-up period. The pattern of CCT change rate according to modes of treatment and history of angle-closure attack was analyzed using the repeated linear mixed model analysis.

Results: A total of 52 eyes were enrolled. The CCT reduction rate of the entire study population was - 0.72 ± 0.22 μm/yr (P = 0.001) with statistical significance. The CCT thinning rate of the laser peripheral iridotomy (PI) group was - 0.53 ± 0.25 μm/yr (P = 0.034) and that of the surgical trabeculectomy group was - 1.32 ± 0.43 μm/yr (P = 0.002), and it was not statistically significant (P = 0.112). The rate of CCT thinning in patients with a history of acute angle-closure attack was - 0.81 ± 0.31 μm/yr (P = 0.009) and that in patients without an attack was - 0.63 ± 0.30 μm/yr (P = 0.001), and it was not statistically significant (P = 0.680). Baseline CCT appeared to be the only significant factor affecting the rate of CCT changes (P < 0.001).

Conclusions: We found a significant reduction in CCT over a long observation period in PAC eyes. We also found that the rates of CCT reduction were not affected by different treatment modalities or acute angle-closure attacks. The analysis of long-term CCT changes in conjunction with baseline CCT would also be helpful in the clinical evaluation of the PAC patients.