Effects of Lens Extraction versus Laser Peripheral Iridotomy on Anterior Segment Parameters in Primary Angle Closure Suspects: A Systematic Review and Meta-analysis

Background

Primary angle closure suspect (PACS) is characterized by an anatomically narrow anterior chamber angle, predisposing individuals to angle closure and subsequent glaucomatous damage. Prophylactic interventions including laser peripheral iridotomy (LPI) and lens extraction (LE) can be employed to mitigate this risk, especially in high-risk patients. While both procedures aim to widen the iridocorneal angle, their comparative efficacy in improving anterior segment parameters remains a subject of ongoing investigation.

Purpose

This meta-analysis aimed to evaluate the comparative effects of lens extraction (LE) and laser peripheral iridotomy (LPI) on anterior segment parameters in primary angle closure suspects (PACS). The analysis encompassed a range of metrics, including angle opening distance (AOD), trabecular iris space area (TISA), trabecular iris angle (TIA), iris curvature (I-CURV), trabecular-ciliary process distance (TCPD), lens vault (LV), and mean Shaffer gonioscopy grading.

Method

A comprehensive search was conducted across PubMed, Scopus, Web of Science (WOS), and Cochrane Library to identify studies comparing the effects of laser peripheral iridotomy (LPI) and lens extraction (LE) on anterior segment morphology. Studies of all original design were included except case reports and case series. Effect estimates for continuous outcomes were expressed as mean differences (MD) with 95% confidence intervals (CIs). Meta-analysis was performed using Review Manager (version 5.4). The methodological quality of the included studies was evaluated using the Newcastle-Ottawa Scale (NOS) tool.

Results

Four studies met the inclusion criteria for the meta-analysis. LE demonstrated consistently greater improvements compared to LPI in both short-term (1 month) and long-term (2 years) follow-up across all evaluated metrics. At one month, LE resulted in significantly larger anterior chamber angle metrics, including AOD500 and AOD750 (mean differences: −0.19 mm and −0.26 mm, respectively; both p < 0.00001), with these effects persisting at two years. Similarly, TISA500 and TISA750 were notably larger after LE (mean differences: −0.07 mm² and −0.21 mm²; both p < 0.00001). LE also achieved a greater reduction in TIA (−21.85 °; p < 0.00001), while I-CURV and TCPD improvements significantly favored LE (both p < 0.00001). Additionally, LV increased more substantially following LE (0.86 mm; p < 0.00001). Mean Shaffer gonioscopy grading also showed superior outcomes with LE (Standardized mean difference (SMD): −2.49; p < 0.00001).

Conclusion

LE consistently enhances anterior chamber dimensions, including AOD, TISA, and TIA, with benefits sustained for up to two years in patients with PACS. These anatomical improvements suggest a more effective long-term approach to reducing intraocular pressure and preventing disease progression. Clinicians should consider early LE in appropriate patients to optimize angle widening and minimize the need for additional interventions.