Purpose: This study conducted long-term measurements of the anterior chamber depth (ACD) in late middle-aged patients with either primary angle closure suspect (PACS) or primary angle closure (PAC) using anterior segment optical coherence tomography (AS-OCT) with the purpose of evaluating their yearly changes.
Subjects and methods: The study involved 22 eyes of 11 patients aged<65 who were diagnosed with either PACS or PAC at an initial examination and underwent ACD measurements with an AS-OCT device (SS-1000 CASIA^Ⓡ, TOMEY). ACD was defined as the distance from the corneal endothelium to the anterior surface of the lens. The mean age was 50.6±6.1 (44-63) years, and the female to male ratio was 10: 1. Overall, 18 eyes had PACS and 4 eyes had PAC. Initially, the mean ACD was 2.035±0.228 (1.607-2.431) mm, and the mean axial length was 22.62±1.09 (21.37-25.51) mm. The mean follow-up period was 1549.5±762.2 (601-2,660) days.
Results: At the final observation, the mean ACD was 1.902±0.174 (1.593-2.255) mm, which significantly reduced compared to that at the initial examination (p=0.0486). The mean reduction rate of ACD was -0.0289 mm/year and negatively correlated with ACD measured at the initial examination (r=-0.4547, p=0.0335, Pearson correlation coefficient test). Ten of 18 (55.6%) eyes with PACS progressed to PAC. However, the formation of peripheral anterior synechia (PAS) was not significantly correlated with the reduction rate of ACD (p=0.0916, Mann-Whitney U test).
Conclusion: In late middle-aged patients, the reduction rate of ACD in eyes with angle closure may be faster than that previously reported (-0.013 mm/year, mean age: 66.1±3.9 years).
Nippon Ganka Gakkai Zasshi (J Jpn Ophthalmol Soc) 125: 1099-1103, 2021.