Evaluation of Refractive Status and Ocular Biometric Parameters in Primary Angle Closure Disease

Abstract

Introduction: The aim of the study was to evaluate the refractive status and ocular biometric parameters in subjects with angle closure in Malaysia. Methods: This cross-sectional study was conducted on 171 primary angle closure patients (268 eyes). Visual acuity, refraction, and ocular biometry (central anterior chamber depth [ACD], axial length [AL], and lens thickness) were recorded. Vitreous cavity length (VL) and relative lens position (RLP) were calculated. Results: A total of 92 Primary Angle Closure Suspect (PACS), 30 Primary Angle Closure (PAC), and 146 Primary Angle Closure Glaucoma (PACG) eyes were included. Chinese ethnicity formed the majority (n = 197, 73.5%), followed by Malay (n = 57, 21.3%) and Indian (n = 14, 5.2%). There was a significant female preponderance with a female to male ratio of 1.85. Mean age was 65.7 ± 7.7 years. Mean spherical equivalent was +0.33 ± 1.29 D. Approximately half (n = 137, 51%) of the eyes were hyperopic (spherical power ≥+0.5), with PACG having the highest percentage of hyperopia (n = 69, 50.4%). Myopia and emmetropia were present in 48 (17.9) and 83 (31%) eyes, respectively. Although AL and VL in myopia patients were significantly longer than emmetropic and hyperopic eyes (p < 0.001), the ACD was not significantly different (p = 0.427). While the RLP is smaller in myopic eyes, lens thickness was increased in hyperopic eyes. PACG was significantly higher in elderly patients compared to PACS and PAC (p = 0.005). A total of 37 (13.8%) eyes were blind (vision worse than 3/60) and 19 of them (51.3%) were female patients. Conclusion: A decrease in RLP is predictive of angle closure disease in myopic eyes, whereas increased lens thickness contributes to angle closure disease in hyperopic eyes.

Prevalence and risk factors for primary angle-closure disease spectrum: The Colombian glaucoma study

“…However, recent studies propose that lens parameters would be stronger determinants of anterior chamber depth than axial length and that an increased thickness and anteriorly positioned lens, as occurs in hyperopic eyes, would confer a greater risk of PAC-DS in these subjects. 37 In people with diabetes and higher values of blood glucose, refractive changes have been reported with controversial findings. 38 Most studies suggest that a higher risk of myopia could increase in hyperglycemic subjects, which could explain by changes in the structure and biochemical composition of the lens.…”

Prevalence and Ocular Biometric Characteristics of Myopia in Primary Angle Closure Disease in Rural China: The Handan Eye Study

“…Our findings were in concordance with a previous study, which reported that persons with myopia with angle closure had longer axial length and vitreous length, but similar ACD to those without myopia but with angle closure. 17 Loh et al 27 found that relative lens position is more forward in patients with myopic angle closure. In addition, we observed an age-related tendency toward shallower anterior chambers and thicker lenses in persons with myopia with PACD, consistent with a prior prospective observational study conducted in healthy subjects.…”

The Influence of 0.5% Tropicamide on Anterior Segment Parameters With CASIA2 in Emmetropic, Myopic, and Hyperopic Eyes

“…ACD and ACW are key factors in the diagnosis of glaucoma. ( Chen et al, 2013 ; Loh et al, 2021 ) For instance, shallow ACD may increase the risk of angle-closure glaucoma. In addition, ACD is a critical parameter in the implantation of pIOL.…”