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A. Raj, K. R. Martin; A Comparison of the Efficacy and Complications of Two Cyclodiode Laser Treatment Protocols in Refractory Glaucoma. Invest. Ophthalmol. Vis. Sci. 2010;51(13):4457.
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© ARVO (1962-2015); The Authors (2016-present)
Trans-scleral cyclophotocoagulation (‘cyclodiode’) is an established treatment in the management of refractory glaucoma. Previously studies show a wide variation in energy settings used for reducing intraocular pressure (IOP) but little has been published comparing different protocols. Two different cyclodiode protocols have been used in our department, differing in total energy delivered. Our aim was to compare the efficacy and complications of these protocols.
A theatre register kept at Addenbrooke’s Hospital, UK, was used to identify retrospectively patients who had received cyclodiode therapy in the previous 2 years according to a low energy (Group 1, ≤90J, mean 74.1J, SD 19.5J) or high energy (Group 2, >90J, mean 121.4J, SD 15.3J) protocol. Exclusion criteria were follow-up of less than 6 months and incomplete data. In line with previously published studies, markers of success included IOP < 22mmHg, IOP < 17mmHg, and IOP reduction > 30%. Hypotony was defined as an IOP less than 5mmHg. Data were analysed using Microsoft Excel 2007.
Fifty three patients were identified in total. There was no significant difference between Group 1 (n=32) and Group 2 (n=21) with respect to age, starting IOP, diagnosis, and follow up (p=0.28, 0.18, 0.12 and 0.33 respectively). 59.4% of Group 1 were male, compared to 71.4% of Group 2. Number of medications pre-treatment were similar in both groups (2.7 vs 2.4, p=0.16). At final follow up, mean IOP and change in IOP showed no statistical difference between the 2 groups (16.5 mmHg and 60.5% vs 14.8mmHg and 64.1%, p=0.06 and p=0.27 respectively). Mean change in medication was similar in both groups (0.9 vs 1.1, p=0.25). Group 2 achieved IOP < 22mmHg and IOP < 17mmHg in 85.7% and 66.7% of patients respectively vs 78.1% and 56.3% in Group 1 (p=0.25 and 0.23). Those in Group 1 achieved IOP reduction > 30% in 96.9% of patients vs 90.5% in Group 2 (p=0.17). However, 3 patients developed hypotony in group 2 compared to none in group 1. Other complications were also more frequent in Group 2, including retinal detachment, uveitis and corneal epitheliopathy.
Within the limitations of a retrospective study, we found no significant difference in the IOP lowering efficacy between our high and low energy cyclodiode protocols but there were more complications in the high energy group. On the basis of these results, a larger prospective study is planned.
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