Histological effect of semi-conductor diode laser trans-scleral cyclophotocoagulation on buphthalmic equine globes

Purpose

To determine if the currently used location and energy settings for semiconductor diode laser trans-scleral cyclophotocoagulation are appropriate for buphthalmic equine globes.

Background

Glaucoma is a common vision-threatening sequela to Equine Recurrent Uveitis. The glaucomas are a group of diseases resulting from alterations in the formation and drainage of aqueous humor (clear eye fluid), which causes an increase in intraocular pressure (IOP) above that compatible with normal function of the retina and optic nerve. This often results in retinal and optic nerve degeneration, blindness, and variable degrees of pain. Previous studies have proven that the diode laser TSCP has the capability of providing long-term IOP reduction for equine glaucoma. Currently, the setting/position for the diode laser TSCP is based on studies previously done in normal horse eyes. However, this may not relate well to the proper position in the glaucomatous eye because as the eye increases in size with chronic glaucoma, the ciliary body (the tissue that is targeted by laser surgery) may move in position. Therefore, the goal of this study is to determine if the currently used location and energy setting for the diode laser TSCP are correct for treatment of equine glaucoma.

Inclusion Criteria

  • Horses with a blind glaucomatous eye that are already undergoing general anesthesia to have the eye removed

Study Design

For this study, any client-owned horse with a blind glaucomatous eye that has already decided to undergo general anesthesia to have the eye removed can be enrolled in the study. Immediately prior to removal of the eye, the axial globe length and corneal dimensions will be measured and routine laser transscleral cyclophotocoagulation will be performed (the entire procedure should take approximately 5-10 minutes). The eye will then be removed and histopathology will be performed.

Client Compensation

  • The study covers the cost for histologic processing of the globe
  • The study will deduct $100 off the client's bill

Client Cost

  • The owner is responsible for all costs of hospital service fees, ophthalmic examination, pre-anesthetic labwork, general anesthesia, preoperative antibiotics and non-steroidal anti-inflammatory medications, enucleation procedure, surgical instrument and room fees and hospitalization.

Contact

Dr. Anne Metzler, metzler [dot] 134 [at] osu [dot] edu for further information.