Clinical outcome evaluation of selective laser trabeculoplasty as the initial therapy for primary open angle glaucoma

Abstract

Background Selective laser trabeculoplasty (SLT) is one of common therapies for early-stage primary open angle glaucoma (POAG).However,it always been used as a method of treating medically uncontrolled open angle glaucoma in China.So the assessment of efficacy of SLT as the initial therapy for POAG is still lack.Objective This clinical study was to compare the efficacy of SLT in early-stage POAG eyes with or without primary medical therapy.Methods A prospective non-randomized controlled study was designed.Sixty-five eyes of 37 patients with early-stage POAG were divided into without pre-treated group (30 eyes of 16 patients) and with pretreated group (35 eyes of 21 patients).SLT was performed on the inferior trabecular meshwork of 180° in all the patients aged 12-57 years old using a 532 nm frequency-doubled,Q-switched Nd:YAG laser with the pulse 3 ns,spot diameter 400 μm.The emitting energy was set from an initial energy of 0.6 mJ to decreased energy successively at 0.1 mJ interval till bubbles coming out.The following-up was 6 months.Primary outcome of SLT included the changes of intraocular pressure (IOP) and effective rate,and the secondary outcome included the perimetry and C/D value.The safety index was evaluated as the incidence of irritative symptom.Results After SLT 1 day to 6 months,the IOP was lower than that before SLT in all the patients (all at P＜0.05).The IOP was (24.03± 3.76)mmHg and (19.18±3.86)mmHg respectively at preoperation and postoperative 1 month in without pretreated group,with a mean decreasing value of (4.85 ±4.31)mmHg,in with pretreated group,the IOP was (23.63±4.29)mmHg at preoperation and (17.07±4.15)mmHg at postoperative 1 month,with a mean difference of (6.28±3.57)mmHg,with a significant difference in the IOP lowing value between the two groups (P =0.045),but there were no significant differences in the IOP lowing value between without and with pretreated groups in 1 hour,1 day,3 months and 6 months after SLT (all at P＞0.05).The effective rate was 75.00％ and 76.67％ in without and with pretreated groups respectively at the end of following-up (P =0.882).No obvious changes were seen in visual field and C/D value before and after SLT in both groups.Also,no serious complication was found in the patients during the following-up duration.Conclusions SLT has a good outcome in lowing-IOP for early stage POAG.There is no obvious impact to the clinical efficacy of SLT whether with or without the primary administration of anti-glaucomatous eye drops.Long-term effect of SLT remains to be observed. Key words: Glaucoma, open angle/surgery; Intraocular pressure; Laser therapy/method; Trabeculectomy/method; Selective laser trabeculoplasty; Prospective study