Background/aims: Transscleral diode laser cyclophotocoagulation (''cyclodiode'') is widely used to treat refractory glaucoma. The main aims of this study were to investigate the dose-response relation of cyclodiode and to evaluate possible predictive factors that would help establish optimum treatment parameters. Methods: A retrospective analysis of the case notes of 263 eyes of 238 consecutive patients who underwent transscleral diode laser cyclophotocoagulation at two centres was undertaken. Results: Mean intraocular pressure (IOP) decreased significantly from 40.7 mm Hg (SD 13.7) before cyclodiode therapy to 17.7 mm Hg (SD 10.9) post-treatment, a reduction of 52.6% (p = 0.0001). Following cyclodiode, 89% of patients achieved an IOP of less than 22 mm Hg or a greater than 30% drop in IOP. Hypotony occurred in 9.5% of patients, 76% of whom had neovascular glaucoma. A linear dose relation response was found for the 122 eyes with neovascular glaucoma (p = 0.001) but not for the group as a whole. Treatment failure was associated with male sex (multivariate regression analysis, p = 0.008) and low mean energy per treatment session (univariate analysis alone, p = 0.016). High pretreatment IOP (p = 0.031) and high mean energy per treatment episode (p = 0.001) appeared to be associated with the occurrence of hypotony, although multivariate analysis did not support this finding. Conclusion: Cyclodiode therapy is highly effective but there is a significant risk of hypotony, which may be reduced by applying lower energy in cases of very high pretreatment IOP and in neovascular glaucoma. The dose-response association remains unpredictable, although a linear relation was found for neovascular glaucoma.
Local anaesthesia for trans-scleral cyclodiode laser procedures: surgeon and patient satisfaction with sub-Tenon's and peribulbar anaesthesia This was a prospective assessment of routine practice for two glaucoma specialists at the same institution. One specialist routinely used a small volume posterior sub-Tenon's LA (2 mL of 2% lidocaine via a Stevens type long metal cannula); the other used a one-site peribulbar approach (6 mL of 2% lidocaine via infero-temporal approach). Laser settings and technique were the same for both specialists. The Iris Medical OcuLight SLx laser (810 nm) was used. Standard technique was to apply 40 laser shots of 1500 mW power and 1500 ms duration, using the G-probe. The globe was transilluminated in order to identify the ciliary body, prior to commencing laser treatment. Treatment was delivered to 360°, except for the 3 o'clock and 9 o'clock positions (long ciliary nerves and vessels) and sites of previous glaucoma surgery.We looked at patient discomfort scores for LA and for the laser itself. Patients were asked to rate their discomfort using a 0-10 scale (0 = no discomfort, 10 = worst pain imaginable). Chemosis and/or subconjunctival haemorrhage in the perilimbal area could interfere with laser application, so this was also recorded on a scale of 0-12 clock hours. At the end of the procedure, we assessed eye movement and lid closure. We asked all patients if they would be happy to have the same LA again, if the procedure needed to be repeated.Results are summarized in the table. Thirty-three patients had peribulbar LA, and 50 had sub-Tenon's LA. Pain scores for both LA techniques were low, with mean pain score in the order of 3/10 for both peribulbar and sub-Tenon's LA. Mean score for the laser itself was around 1/10 for each LA technique. Other 'patient acceptability' criteria appear in the table.Conditions for applying the laser were assessed (Table 1). There was a low rate of chemosis and haemorrhage in the perilimbal area. There were no complications that could be ascribed to LA technique.Our study shows that sub-Tenon's LA and peribulbar LA can both provide adequate anaesthesia for cyclodiode laser to the ciliary body.Pain scores were low for both groups. Peribulbar anaesthesia was associated with slightly lower pain scores, both for the LA and for laser application. However, more patients in the peribulbar group were given a 'top-up' LA (36% vs. 4%), and more patients in the peribulbar group stated that they would not wish to have the same LA/procedure again (18% vs. 0%). A prospective
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