Comparative study of the efficacy of lens extraction and laser peripheral iridotomy in primary anterior chamber angle closure

Abstract

PURPOSE. To compare the anatomical and functional effectiveness of lensectomy (LE) and laser peripheral iridotomy (LPI) in patients with primary anterior chamber angle closure.METHODS. This prospective study included 120 patients aged 41 to 80 years (60 eyes — primary angle closure (PAC), 30 — primary angle closure suspects (PACs), 30 eyes — without ophthalmic pathology). 30 PAC eyes were treated using LE with intraocular lens implantation, and 30 eyes with LPI. All subjects underwent swept source optical coherence tomography (SS-OCT). The following parameters were analyzed: spherical equivalent (SE), uncorrected and corrected distance visual acuity, intraocular pressure (IOP), Shaffer grade of angle opening, lens opacity, goniosyne chiae, choroidal thickness in the macular region, axial length (AL) of the eye, anterior chamber depth (ACD), lens vault (LV), iris curvature (ICurv), iris thickness at 750 µm from scleral spur (IT750), angle opening distance (AOD500, AOD750), iridotrabecular space area (TISA500, TISA750). Along with standard descriptive statistics methods, machine learning methods were used, including Data Driven Soft Independent Modelling of Class Analogies (DD-SIMCA).RESULTS. Every third eye with PAC had reached control group values after LE (DD-SIMCA specificity 0.67), which was not the case after LPI (DD-SIMCA specificity 1.0) with the probability of getting into the control group estimated as 0.01. After LE, all parameters of the anterior chamber angle did not significantly differ from the norm (p>0.05 for all), while ACD, ICurv even exceeded the norm (p=0.000). After LPI, there was a deepening of the ACD (from 2.34±0.28 mm to 2.36±0.280 mm, p=0.000) and a decrease in LV (from 0.864±0.120 µm to 0.843±0.110 µm, p=0.000), however, the result comparable to control was achieved only in ICurv (p=1.000). After LE in PAC, all parameters, including uncorrected visual acuity, SE, ACD, LV, iris profile, Shaffer grade of angle opening, and AOD500, AOD750, TISA500, TISA750 parameters in the superior and inferior sectors had advantages over those in PACs without treatment (p<0.05). After LPI, an improvement in a number of pa rameters was also achieved compared to LPI: ICurv, Shaffer grade of angle opening, AOD500, AOD750, TISA500, TISA750 in the superior sectors and AOD500 in the inferior sector (p><0.05).CONCLUSION. The effectiveness of LE in PAC is higher than LPI due to the better postoperative anterior chamber topography and lower IOP. Both treatments, especially LE, improve these parameters compared to PACs. Lens extraction is the treatment of choice at the early stages of primary angle closure.