Effects of accommodation on geometrical parameters of human lens: A systematic review and meta-analysis

Abstract

PurposeTo investigate the effects of accommodation on the geometrical parameters of human lens. MethodsEight databases from inception to November 2023 were used for the literature search: CNKI, CBM, VIP, Wan-Fang, PubMed, Web of Science, EMBASE, and the Cochrane Library. The Methodological Index for Non-randomized Studies was used to assess the risk of bias. The PRISMA were followed and the following outcomes were taken into consideration: lens diameter (LD), lens thickness (LT), anterior curvature radius (ACR), posterior curvature radius (PCR), lens center position (LCP), and total cross-sectional area (TCSA). This systematic review was registered on an international platform for registered systematic reviews and meta-analysis (INPLASY202260085). ResultsA total of 19 studies were included. LT increased by 0.04 mm/D (18 studies; 95% confidence interval [CI], 0.03–0.06; I2 = 96.6%; P < 0.001). At the same time, LD, ACR, and PCR decreased by 0.06 mm/D (6 studies; 95%CI, −0.07–0.05; I2 = 50.1%; P < 0.001), 0.53 mm/D (8 studies; 95%CI, −0.64–0.41; I2 = 96.5%; P < 0.001), and 0.14 mm/D (9 studies; 95%CI, −0.19–0.09; I2 = 94.7%; P < 0.001) during accommodation, respectively. Moreover, LCP shifted forward by 0.01 mm/D (3 studies; 95%CI, −0.02–0.00; I2 = 0.0%; P < 0.001), and TCSA by 0.58 mm2/D (2 studies; 95%CI, 0.41–1.57; I2 = 97.0%; P = 0.457) during accommodation. ConclusionsChanges in LT, LD, ACR, PCR and LCP supported Helmholtz's theory. Different apparatuses or measurement methods influenced the measurement of lens geometrical parameters.