Effects of cyclophotocoagulation with a neodymium:yttrium-aluminum-garnet laser on corneal sensitivity, intraocular pressure, aqueous tear production, and corneal nerve morphology in eyes of dogs

Abstract

Administration of 100 J with a Nd:YAG laser effectively reduced IOP while increasing CTT and caused a significant decrease in number, but not diameter, of major corneal nerve bundles. Nerve damage and corneal hypoesthesia are etiologic factors in ulcerative keratitis following Nd:YAG cyclophotocoagulation.

Combined transscleral diode laser cyclophotocoagulation and Ahmed gonioimplantation in dogs with primary glaucoma: 51 cases (1996–2004)

“…Corneal ulcers were observed in four eyes after surgery. Previously, laser‐treated (Nd:YAG) canine eyes demonstrated a significantly higher corneal touch threshold, with 6 of 15 laser‐treated eyes developing ulcerative keratitis 19 . The Nd:YAG laser caused significant reduction in the number of major corneal nerves bundles, and this effect may even be more significant in glaucomatous eyes.…”

“…The Nd:YAG laser caused significant reduction in the number of major corneal nerves bundles, and this effect may even be more significant in glaucomatous eyes. Laser energy may damage corneal nerves more in glaucomatous vs. nonglaucomatous eyes because glaucoma may cause a direct mechanical damage to the corneal nerves, decreased sensitivity may be caused by pre‐existent corneal edema, partial ophthalmic neuropathy as well as sensory nerve deformation and ischemia may exist 19 . In two canine glaucoma studies with the diode laser, corneal ulcers were noted in three and eight cases, respectively 9,10 .…”

“…Previously, laser-treated (Nd:YAG) canine eyes demonstrated a significantly higher corneal touch threshold, with 6 of 15 laser-treated eyes developing ulcerative keratitis. 19 The Nd:YAG laser caused significant reduction in the number of major corneal nerves bundles, and this effect may even be more significant in glaucomatous eyes. Laser energy may damage corneal nerves more in glaucomatous vs. nonglaucomatous eyes because glaucoma may cause a direct mechanical damage to the corneal nerves, decreased sensitivity may be caused by pre-existent corneal edema, partial ophthalmic neuropathy as well as sensory nerve deformation and ischemia may exist.…”

Qualitative and quantitative tear film abnormalities in dogs

“…Likewise, damage to the facial nerve (cranial nerve VII) accidentally produced by surgical ablation of the auditory canal was found to be associated with iatrogenic KCS (LANZ & WOOD, 2004). Recently, cyclophotocoagulation of the ciliary body with a laser for the treatment of glaucoma in dogs has been recognized as a potential cause of KCS, favoring the installation of corneal ulcers (WEIGT et al, 2002).…”

Diode Laser Cyclophotocoagulation

“…96 Administration of 100 J with a Nd:YAG laser increases corneal touch threshold and causes a significant decrease in number, but not diameter, of major corneal nerve bundles. 97 Nerve damage and corneal hypoesthesia are etiologic factors in ulcerative keratitis following Nd:YAG cyclophotocoagulation. 95 Results of the preliminary study by Raivio VE et al 98 suggest that cyclophotocoagulation with the 670 nm diode laser does not impair corneal innervation.…”