Can ultrasonic biometric indices with optimal cut-offs be a potential screening tool for primary angle closure disease? A case-control study

Abstract

Background/ Objectives : Despite a significant disease burden and potential to cause blindness, primary angle closure disease (PACD) does not have a population-based screening programme.Biometric indices using ultrasound A-scan is a potential tool for glaucoma case-detection.Given that genetic and environmental factors influence these parameters and paucity of data on their discrimination thresholds in Indian populace, we conducted a matched case-control study to determine the biometric indices and their discrimination thresholds associated with PACD.Methods: We studied 172 eyes of 86 participants (43 cases;43 controls). We compared the following biometric parameters of cases (PACD, occludable angle 180° raised intraocular pressure) with age and gender matched controls (1:1): Anterior chamber depth (ACD), lens thickness (LT), axial length (AXL), lens position (LP), relative lens position (RLP), lens axial factor (LAF), simple crowding value (Cs), ACD/AXL). We performed conditional logistic regression (to identify factors associated with PACD) and Receiver operating characteristic (ROC) analysis (to determine discrimination thresholds).Results: Reduced ACD (Adj OR 0.01; 95% CI: 0.0003-0.15, p<0.001) and increased LT (Adj OR 10.3; 95% CI:2.42-43.93, p<0.001) were associated with PACD. On ROC analysis, ACD, Cs, and ACD/AXL had optimum sensitivity/specificity at  3.015,  0.056, and,  0.1303, respectively. ACD (88.4%) and Cs (94.2%) had highest sensitivity and specificity, respectively. Conclusion:Ultrasonic biometric parameters differed significantly between PACD and controls. ACD and Cs (at discrimination thresholds of 3.015mm and  , respectively) using ultrasound A-scan could be a potential tool for PACD case-detection that requires evaluation of its diagnostic yield and cost-effectiveness.

Agreement on Anterior Chamber Depth Measurement between Three Commercially Available Devices

“…The differences in the precision or agreement between devices are a relevant research topic; accurate biometric results are crucial in the modern diagnosis of ectasias, myopia control or even cataract and refractive surgery for the effective management of patients. ACD quantification serves as a valuable tool for the early diagnosis of ocular disorders, as well as for precise intraocular lens power calculations and routine ocular surgeries [3][4][5][6][7], and has even recently been proposed as one of the features to be studied in myopic populations [48]. In the present study, the agreement on ACD measurements of three commercially available devices based on different measurement principles was assessed, with and without compensation by CCT measurement.…”

“…Anterior chamber depth (ACD) refers to the distance between the corneal epithelium and the anterior capsule surface of the crystalline lens, whereas anterior aqueous depth (AQD) refers to the distance between the corneal endothelium and the anterior capsule surface of the crystalline lens [1,2]. The precise quantification of these parameters provides a tool for the early diagnosis and monitoring of exogenous and endogenous ocular disorders, accurate intraocular lens power calculations or ocular surgery [3][4][5][6][7]. ACD measured by ultrasonic biometry has even been proposed as one parameter to differentiate primary angle closure disease patients from control patients [3].…”

“…The precise quantification of these parameters provides a tool for the early diagnosis and monitoring of exogenous and endogenous ocular disorders, accurate intraocular lens power calculations or ocular surgery [3][4][5][6][7]. ACD measured by ultrasonic biometry has even been proposed as one parameter to differentiate primary angle closure disease patients from control patients [3]. Moreover, a shallow ACD has been established to be critically associated with intraoperative complications of cataract surgery and poor clinical outcomes [4].…”

Variations in Lens Thickness Affecting the Anterior Chamber Length and Their Potential Measurement Using a Biometer

“…Several techniques have been used to measure ocular biometry, such as ophthalmophakometry and A-scan ultrasonography. The latter method has emerged as a potential tool for the early detection of ocular pathologies such as glaucoma [5,6].…”