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Diode laser endoscopic cyclophotocoagulation in the normal equine eye
Author(s) -
Harrington Jay T.,
McMullen Richard J.,
Cullen John M.,
Campbell Nigel B.,
Gilger Brian C.
Publication year - 2013
Publication title -
veterinary ophthalmology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.594
H-Index - 50
eISSN - 1463-5224
pISSN - 1463-5216
DOI - 10.1111/j.1463-5224.2012.01035.x
Subject(s) - ciliary processes , medicine , ophthalmology , intraocular pressure , cornea , ciliary body , glaucoma , edema , corneal epithelium , surgery
Objective To determine the clinical and histologic effects of diode endoscopic cyclophotocoagulation (ECP) in the phakic equine eye. Animals studied Phase I: 10 equine cadaver eyes. Phase II: four normal adult horses. Procedures Phase I: ECP probe angle of reach (AR) was determined. Multiple ECP energy levels: 0.75, 0.90, 1.05, 1.20, 1.35, 1.50 J, and the resulting visible and histologic ciliary process changes were evaluated. Phase II: Ocular quadrants were treated with ECP at 0.90, 1.14, 1.38 J, and a control. The contralateral eye underwent a sham operation. Tissue changes (clinical and histologic) were evaluated. Results Phase I: Mean combined AR was 162 ± 29 degrees. Mean visible tissue scores: 2.60 ± 0.58 (0.75 J) to 5.04 ± 0.30 (1.50 J) from possible total of 6. Tissue ‘popping’ was observed at 1.50 J. Histologic ciliary tissue damage was present at all settings. Phase II: Mean visible tissue scores: 2.90 ± 0.48 (0.90 J), 3.61 ± 0.57 (1.14 J), and 4.52 ± 0.56 (1.38 J). Tissue ‘popping’ was observed at 1.38 J. Histologic ciliary tissue damage was present at all settings. Clinical effects included acute inflammation, intraocular pressure reduction, cataract formation, corneal edema, corneal ulceration, and postoperative ocular hypertension. Conclusions Diode ECP between 0.90 and 1.14 J is a potential treatment option for glaucoma in horses based on visible tissue effects and target ciliary epithelium damage. Iatrogenic cataract development may limit the use of an anterior chamber approach in phakic horses. Supported in part by an ACVO VAF grant.