Effect of diode laser contact transscleral pars plana photocoagulation on intraocular pressure in glaucoma

Purpose : To evaluate the efficacy of diode laser contact transscleral pars plana photocoagulation (CTPPP) for intraocular pressure (IOP) control in glaucoma and its clinical application. Method : A prospective, non-randomized hospital-based pilot study was conducted. Fourteen patients with poor visual acuity (VA worse than 6/60) and medically uncontrolled, refractory glaucoma were recruited, and CTPPP was performed after informed consent. Results : Mean preoperative IOP was 41.0 mmHg (SD 12.6, range 27-70, n = 14). At 1 week postoperatively, IOP was reduced in 12 of 14 (86%) patients to a mean of 28.6 mmHg (SD 15.8, range 3-55, n = 14). This represented a mean decrease of 12.4 mmHg. Mean IOP was 34.0 mmHg (SD 17.4, range 5-71, n = 14) and 31.6 mmHg (SD 13.4, range 5-22, n = 12) at 4 and 12 weeks, respectively. The IOP reduction was significant at 1 week (P = 0.001, paired t -test) and at 12 weeks (P = 0.04, paired t -test). The two patients with preoperative pain reported abolition of pain after the procedure. Seven of 13 patients on preoperative antiglaucoma eye drops did not require eye drops postoperatively. Conclusions : Diode laser CTPPP was found to significantly reduce IOP in the majority of patients at 1 week postoperatively, with less but still significant effect at 12 weeks. Its potential application as a procedure for short-term IOP reduction in medically uncontrolled glaucoma requiring filtering surgery needs to be further investigated.