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Home / Equine Research Bank / Vet Ophthalmol / The location of sites and effect of semiconductor diode tran...
Veterinary ophthalmology2014; 17 Suppl 1(0 0); 107-116; doi: 10.1111/vop.12166

The location of sites and effect of semiconductor diode trans-scleral cyclophotocoagulation on the buphthalmic equine globe.

Abstract: To determine appropriate location and energy settings for trans-scleral cyclophotocoagulation (TSCPC) for buphthalmic equine globes. Methods: Eleven horses with a buphthalmic eye blinded by glaucoma presented for enucleation. Methods: Globe and corneal dimensions were measured via ultrasonography and calipers, and TSCPC was performed under general anesthesia immediately prior to enucleation. Part 1: In nine globes, sixty sites were lasered 4 mm posterior to the limbus in the dorsotemporal and ventrotemporal quadrants at settings of 1500 milliwatts and 1500 ms. Globes were processed and sectioned sagitally over the temporal aspect in two blocks, each with five histologic sections examined by light microscopy. A digital imaging system was used to determine the location and length of the pars plicata on one slide from each block. Part 2: Based on results in Part 1, two globes were measured and lasered using the same time and energy settings at the following distances posterior to the limbus: 8 mm dorsally, 6 mm dorsotemporally, 5 mm ventrotemporally, and 5 mm ventrally. Results: Globe and corneal dimensions exceeded normal values in all globes. Part 1: In all nine globes, photocoagulation affected the anterior ciliary processes and iris base and in 8/9 coagulation of the pectinate ligaments was noted. Part 2: In both globes, coagulation was confined to the pars plicata. Conclusions: The previously recommended TSCPC sites are located too far anteriorly for a buphthalmic globe. Buphthalmic equine globes should have TSCPC performed at the following distances posterior to the limbus: 6-8 mm dorsally, 5-6 mm dorsotemporally, 4-5 mm ventrotemporally, and 4-5 mm ventrally.
© 2014 American College of Veterinary Ophthalmologists.
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Publication Date: 2014-04-03 PubMed ID: 24697980PubMed Central: PMC4082759DOI: 10.1111/vop.12166Google Scholar: Lookup
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Summary

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This research paper investigates the ideal location and energy settings for a laser procedure called trans-scleral cyclophotocoagulation (TSCPC) on horses with a buphthalmic eye condition caused by glaucoma. The author concluded that previous TSCPC sites were too far forward for a buphthalmic globe of a horse’s eye and suggested new locations for the procedure.

Research Methodology

  • The researchers studied 11 horses with glaucoma-induced buphthalmic eyes that were presented for eye removal (enucleation).
  • The dimensions of the eye globe and cornea were measured using ultrasonography and calipers.
  • TSCPC was performed on these horses under general anesthesia just before the enucleation procedure.
  • In the first part of the experiment, nine eyes were laser treated at sixty sites, 4mm behind the limbus in the dorsotemporal and ventrotemporal quadrants at settings of 1500 milliwatts and 1500 ms.
  • The globes were processed and cut sagittaly along the temporal aspect, then examined under a microscope. A digital imaging system determined the location and length of the pars plicata.
  • In the second part of the experiment, based on the previous results, two globes were measured and TSCPC was performed at differing distances posterior to the limbus with the same time and energy settings.

Results of the Research

  • They saw that all the globe and corneal dimensions exceeded regular values in all globes.
  • In all nine globes from the first part of the experiment, the laser treatment affected the ciliary processes at the front and the base of the iris. In eight out of nine cases, coagulation of the pectinate ligaments was observed.
  • In the second part of the experiment, in both globes, coagulation was confined to the pars plicata.

Conclusions of the Study

  • The research concluded that the previously recommended locations for TSCPC treatment were too far anteriorly for a buphthalmic globe in the cases of glaucoma in horses.
  • The authors suggest that TSCPC treatment for buphthalmic equine globes be performed at the following distances posterior to the limbus: 6-8 mm dorsally, 5-6 mm dorsotemporally, 4-5 mm ventrotemporally, and 4-5 mm ventrally.

Cite This Article

APA
Gemensky-Metzler AJ, Wilkie DA, Weisbrode SE, Kuhn SE. (2014). The location of sites and effect of semiconductor diode trans-scleral cyclophotocoagulation on the buphthalmic equine globe. Vet Ophthalmol, 17 Suppl 1(0 0), 107-116. https://doi.org/10.1111/vop.12166

Publication

Veterinary ophthalmology
ISSN: 1463-5224
NlmUniqueID: 100887377
Country: England
Language: English
Volume: 17 Suppl 1
Issue: 0 0
Pages: 107-116

Researcher Affiliations

Gemensky-Metzler, Anne J
  • Department of Veterinary Clinical Sciences, The Ohio State University College of Veterinary Medicine, Columbus, OH, 43210, USA.
Wilkie, David A
    Weisbrode, Steven E
      Kuhn, Sonia E

        MeSH Terms

        • Animals
        • Female
        • Horse Diseases / pathology
        • Horse Diseases / surgery
        • Horses
        • Hydrophthalmos / pathology
        • Hydrophthalmos / surgery
        • Hydrophthalmos / veterinary
        • Laser Coagulation / instrumentation
        • Laser Coagulation / methods
        • Laser Coagulation / veterinary
        • Lasers, Semiconductor
        • Male

        Grant Funding

        • P30 CA016058 / NCI NIH HHS

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