Diode laser endoscopic cyclophotocoagulation in the normal equine eye.
Abstract: To determine the clinical and histologic effects of diode endoscopic cyclophotocoagulation (ECP) in the phakic equine eye. Methods: Phase I: 10 equine cadaver eyes. Phase II: four normal adult horses. Methods: 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.
© 2012 American College of Veterinary Ophthalmologists.
Publication Date: 2012-05-29 PubMed ID: 22640524DOI: 10.1111/j.1463-5224.2012.01035.xGoogle Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The research article explores the effects of diode endoscopic cyclophotocoagulation (ECP), a possible treatment for glaucoma, on a horse’s eye. The study found noticeable tissue changes and damage to the target ciliary epithelium at multiple energy levels, with potential side effects including inflammation, reduced intraocular pressure, and cataract development.
Research Methodology
The study was carried out in two key phases.
- In Phase I, 10 equine cadaver eyes were experimented on with varying energy levels of the ECP procedure, while assessing the subsequent visible and histologic ciliary process changes.
- Phase II was conducted on four live normal adult horses. Again, distinct energy levels of the ECP procedure were utilised and visible tissue damage analysed. Furthermore, the contralateral eye of each horse underwent a sham operation (a fake procedure intended to mimic the real one), perhaps to establish a baseline or to check for placebo effects.
Study Outcomes
Multiple key outcomes were established throughout the study:
- The average combined angle of reach (AR) for the ECP probe was found to be 162 ± 29 degrees.
- Observable tissue changes were apparent at each energy level tested, with degrees of tissue ‘popping’ (the breaking or destruction of tissue during laser treatment) observed at higher energy levels.
- Tissue damage, both visible and histologic, occurred with every energy setting used.
- Several clinical effects were noticed following ECP treatment, including acute inflammation, intraocular pressure reduction, cataract formation, corneal edema, corneal ulceration, and hypertensive responses.
Conclusions
The researchers concluded that Diode ECP, particularly between 0.90 and 1.14 J, could be a viable treatment option for horses with glaucoma. This conclusion was based on observed changes to visible tissue and damage inflicted on the target ciliary epithelium. However, potential side effects, particularly the development of cataracts, could limit the usefulness of this treatment given its adverse effect on the eye’s anterior chamber.
Cite This Article
APA
Harrington JT, McMullen RJ, Cullen JM, Campbell NB, Gilger BC.
(2012).
Diode laser endoscopic cyclophotocoagulation in the normal equine eye.
Vet Ophthalmol, 16(2), 97-110.
https://doi.org/10.1111/j.1463-5224.2012.01035.x Publication
Researcher Affiliations
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27606, USA.
MeSH Terms
- Animals
- Cadaver
- Endoscopes / veterinary
- Eye
- Horses
- Lasers, Semiconductor
- Light Coagulation / instrumentation
- Light Coagulation / methods
- Light Coagulation / veterinary
- Ophthalmologic Surgical Procedures / methods
- Ophthalmologic Surgical Procedures / veterinary
Citations
This article has been cited 3 times.- Biondi V, Pugliese M, Voslarova E, Landi A, Passantino A. Animal Welfare Considerations and Ethical Dilemmas Inherent in the Euthanasia of Blind Canine Patients. Animals (Basel) 2022 Apr 2;12(7).
- Isard PF, Mentek M, Clément D, Béglé A, Romano F, Aptel F, Mathieson I, Dulaurent T. High intensity focused ultrasound cyclocoagulation in dogs with primary glaucoma: a preliminary study. Open Vet J 2018;8(3):305-312.
- Sun W, Yu CY, Tong JP. A review of combined phacoemulsification and endoscopic cyclophotocoagulation: efficacy and safety. Int J Ophthalmol 2018;11(8):1396-1402.
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