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Objective: To describe a combined treatment approach for heterochromic iridocyclitis and secondary keratitis (HIK) in horses., Animal Studied: A total of 15 horses (16 eyes)., Procedures: Sixteen eyes from 15 horses (mean age 14.1 years, range 6-26 years) received low-dose (4 mg) intravitreal preservative-free gentamicin injection (IVGI) and modified Gundersen grafts with standing sedation and local anesthesia following a clinical diagnosis of HIK. Additional therapies of suprachoroidal triamcinolone (8 mg) injection, episcleral bromfenac implants, and suprachoroidal cyclosporine implants were performed in individual cases. Leptospira titers were also reported when available., Results: The most frequent ophthalmic findings were pigmented keratic precipitates (n = 15/16 eyes, 94%), corneal edema (n = 14/16 eyes, 88%), and pigmented cells suspended in the anterior chamber (n = 7/16 eyes, 44%). Postoperative treatment generally consisted of topical and systemic NSAIDs, topical antibiotics, and a topical mydriatic agent. Complications included persistent corneal edema (7/16, 44%), corneal ulceration (6/16, 38%), graft failure requiring revision (2/16, 13%), stromal abscess (1/16, 6%), surgery site infection (1/16, 6%), and suspected retinal degeneration following IVGI (1/16, 6%). One case was enucleated 6 months after treatment (1/16, 6%). Of the 12 eyes with at least 3 months of post-treatment follow-up, 10 were comfortable and visual with static or improved symptoms of HIK., Conclusions: This multimodal treatment approach aims to address both the anterior uveitis and endothelial decompensation frequently seen in horses with HIK. The surgery can be performed under standing sedation. Continued evaluation and long-term follow-up is necessary in all horses with HIK., (© 2024 American College of Veterinary Ophthalmologists.)

Purpose: To evaluate the normal refractive state in horses in NCSU and ECMR and determine the prevalence of naturally occurring refractive errors and their association with breed, age, coat color, iris color, sex, and geographic location., Methods: Horses from NCSU (January 2009-November 2012) and ECMR (January 2013-September 2016) underwent ophthalmic examination and streak retinoscopy. Location, color, breed, sex, and iris color were recorded. Gross and net refractive values for each meridian (horizontal and vertical), spherical refraction, astigmatism for both eyes, and anisometry were recorded, and statistical analyses were performed., Results: There is excellent agreement in refraction between the eyes of the same horse (ICC = 0.89). The median net horizontal (H), vertical (V), and spherical refraction for the total population (n = 690) were H: +0.25 D (min. -6.50 D, max. +2.34 D), V: +0.25 D (min. -7.13 D, max. +2.75D), and spherical: +0.25 D (min. -6.82 D, max. +2.17 D), all with interquartile ranges of -0.25 to 0.25 D. Emmetropia (>-0.50 D and <+0.50 D; >-0.75 D and <+0.75 D) was present in 769/1380 eyes (55.7%) and 926/1380 eyes (67.1%), respectively. Anisometropia was present in 86/690 horses (12.5%). Sex, iris color, and location were significantly associated with refraction values, whereas age, breed, and coat color were not., Conclusions: Most eyes evaluated are emmetropic, or shifted myopically, with excellent agreement between eyes of the same horse. Sex, iris color, and geographic location appear to impact refraction in horses., Support: None., (© 2023 American College of Veterinary Ophthalmologists.)

Objective: Evaluate the effects of corneoconjunctival transposition (CCT), posterior lamellar keratoplasty (PLK) and modified deep lamellar endothelial keratoplasty (DLEK) on streak retinoscopy in equine cadaver eyes., Methods: Intraocular pressure (IOP) was maintained at 25 ± 3 mmHg in 35 equine cadaver eyes. Streak retinoscopy was performed prior to (NO VISCO) and following (VISCO) intracameral injection of 1.0 ml of viscoelastic. Following optical coherence tomography (OCT), an axial CCT [n = 11] or PLK [n = 12], or peripheral DLEK [n = 12] was performed. Streak retinoscopy and OCT were repeated postoperatively., Results: Postsurgical net meridional and spherical refraction for CCT [Horizontal (H): 3.4 (95% CI 2.4-4.4) diopters (D), p < .001, Vertical (V): 3.5 (95% CI 2.7-4.4) D, p < .001, Spherical: 3.5 (95% CI 2.6-4.3) D, p < .001] and PLK [H: 3.2 (95% CI 2.2-4.1) D, p < .001, V: 2.8 (95% CI 2.0-3.6) D, p < .001, Spherical: 3.0 (95% CI 2.2-3.8) D, p < .001] were significantly increased from presurgical (VISCO) values. No difference between presurgical (VISCO) and postsurgical values were identified for the DLEK. Postoperative OCT revealed space between anterior and posterior corneal grafts and corneal undulation associated with suture placement., Conclusion: Meridional and spherical refraction had a hyperopic shift following CCT and PLK, with a significantly higher value in the vertical meridian for the CCT. Pre- and postoperative refraction was not significantly different for the DLEK. This supports that the DLEK has a lesser effect on immediate postoperative refraction compared with CCT or PLK., (© 2022 American College of Veterinary Ophthalmologists.)

Objective: Identify ocular findings associated with blunt ocular trauma to aid in differentiation from other equine ocular diseases., Study Design: Retrospective case-control study., Methods: Medical records of horses at the Equine Clinic Munich-Riem, Munich, Germany and Auburn University, College of Veterinary Medicine were reviewed. Age, sex, breed, laterality, and clinical findings on ophthalmic examination, as well as an observed (confirmed) or unobserved (suspected) history of trauma, were recorded. Statistical analysis was performed to identify any correlation between clinical signs and blunt ocular trauma. Fifty-nine clinical signs were evaluated, and their association with blunt ocular trauma and non-traumatic uveitis was determined. The frequency of clinical signs associated with non-traumatic uveitis was also reported., Results: Fifty-five eyes affected with blunt trauma were included. The comparison group consisted of 233 eyes (168 horses) diagnosed with non-traumatic uveitis. The most frequent ocular findings after BOT included cataract (36/55, 65.5%), corneal edema (26/55, 47.2%), decreased intraocular pressure (23/55, 41.8%), aqueous flare (19/55, 34.5%), lens subluxation, luxation, or lens loss (18/55, 32.7%), fibrin in the anterior chamber (18/55, 32.7%), hyphema (16/55, 29.1%), peripapillary depigmentation ("butterfly lesion") (16/55, 29.1%), conjunctival hyperemia (16/55, 29.1%), corneal fibrosis (15/55, 27.3%), corpora nigra avulsion (14/55, 25.5%), blepharospasm (13/55, 23.6%), and iridodialysis (11/55, 20.0%)., Conclusions: The characteristic pattern of ocular signs associated with blunt ocular trauma may assist in differentiation from other types of uveitis and may improve interpretation of ocular lesions identified during pre-purchase examinations. This study also represents the first peer-reviewed documented and photographed cases of iridodialysis in the horse., (© 2021 American College of Veterinary Ophthalmologists.)