Cataract extraction is a safe and effective surgery that has been performed in its modern form for several decades. Many studies have noted that cataract extraction could also have a clinically significant role in the control of comorbid glaucoma. Lens extraction decreases the pressure within the eye, and intraocular pressure (IOP) is the only controllable risk factor in glaucoma proven to be effective. A systematic analysis of current evidence is needed to establish strong practice patterns and identify areas where further research is required. We performed systematic review and meta-analysis of the clinical data to estimate the net effect of cataract surgery on IOP. A total of 37 treatment arms from 32 different studies from January 1997 to January 2017 were included. IOP reduction was highly correlated across follow-up periods. For angle-closure glaucoma, results showed an IOP decrease of -6.4 mmHg (95% CI: -9.4 to -3.4) at final follow-up (12 months and longer). For the open-angle glaucoma group, there was an overall IOP change of -2.7 mmHg (95% CI -3.7 to -1.7) from baseline. For pseudoexfoliation glaucoma further research is needed to reach an adequate evidence-based conclusion. The influence of inherent sources of bias, including loss to follow-up, washout and medication use, and lack of a control group, was evaluated numerically. These sources of bias pulled the IOP estimate in opposite directions and are therefore unlikely to affect the main conclusions substantially. Future prospective clinical trials, including other outcomes such as quality of life, clinical severity information, and cost-effectiveness analysis, are needed to determine the role of phacoemulsification alone within the glaucoma treatment algorithm.
Keywords: cataract; glaucoma; glaucoma epidemiology; lens extraction; meta-analysis; phacoemulsification.
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