Ciclofotocoagulação tradicional modificada versus slow coagulation no glaucoma refratário : um estudo prospectivo e randomizado

Abstract

This prospective, randomized, and comparative study evaluated the hypothesis that complications of traditional cyclophotocoagulation (CPC) may be related not only to power and time parameters but also to the extent of the treated area. Although more recent protocols involving power reduction and increased exposure time (Slow Coagulation) have demonstrated an excellent efficacy/safety ratio, it was proposed to investigate whether a modification of the traditional technique with a smaller treatment extent could offer similar results. To this end, 48 eyes of 48 patients with refractory glaucoma were included and randomized into two groups of 24 patients each: Group I (GI) underwent a modification of the traditional technique using a power of 2500 mW for 2000 ms, limiting the treatment extent to 210° (180° inferiorly and 30° superiorly) with 21 spots, while Group II (GII) followed the standard Slow Coagulation protocol. After 12 months of follow-up, the intraocular pressure (IOP) reduction in GI was from 27.54 ± 12.65 mmHg to 14.80 ± 9.11 mmHg, and in GII from 33.92 ± 14.08 mmHg to 19.11 ± 11.60 mmHg (p < 0.001 for both). The number of topical medications was reduced from 3.17 ± 0.96 to 1.35 ± 1.42 in GI, and from 3.13 ± 0.95 to 0.94 ± 1.30 in GII (p < 0.001 for both). There was no statistically significant difference between the groups regarding the percentage of IOP reduction (p = 0.092), the reduction in the number of medications (p = 0.823), and visual acuity (p = 0.983), with the latter being preserved throughout the study in both GI (p = 0.868) and GII (p = 0.302). The success rate ranged from 21.0% to 61.1%, depending on the criterion: qualified 1 (GI 49.1%; GII 61.1%; p = 0.430), qualified 2 (GI 57.6%; GII 61.1%; p = 0.829), absolute (GI 21.0%; GII 31.0%; p = 0.207), and optimized (45.1% in both; p = 0.953); with no statistically significant differences between the groups. The predictive factors considered significant for surgical failure or success were: number of eye drops, use of oral acetazolamide, final energy, race, age, and sex. Conjunctival hyperemia was the most frequent complication, with a low number of severe complications in both groups and no statistical difference between them (p = 0.701). Thus, both evaluated cyclophotocoagulation techniques were safe, effective, and similar in the surgical treatment of patients with refractory glaucoma, suggesting that modifying the traditional technique with a smaller treatment extent is one of the pathways to achieve the best efficacy/safety ratio in CPC surgery.