Corneal cross‐linking (CXL)—A clinical study to evaluate CXL as a treatment in comparison with medical treatment for ulcerative keratitis in horses

Abstract

Objective Compare CXL treatment with medical treatment alone in horses with stromal, ulcerative keratitis. Animals studied: 24 horses (24 eyes) with stromal, ulcerative keratitis were included. Procedure 12 horses were initially treated with CXL, and 12 horses were given conventional medical treatment. Topical medical treatment was added to horses in the CXL group if necessary. Parameters including cytology, microbial growth, time to fluorescein negativity, and time to inhibition of stromal melting were evaluated. Results After the first day of treatments, a decrease in inflammatory signs and pain from the eye was observed in both groups. Stromal melting ceased within 24 hours regardless of treatment. CXL treatment alone was sufficient in 3 horses with noninfectious, superficial stromal ulcerations. Clinical signs of impaired wound healing were seen after 3‐14 days in corneas with suspected or proven bacterial infection treated with CXL only, most likely because of insufficient elimination of bacteria deeper in the corneal stroma or because of re‐infection from bacteria in the conjunctiva. The average decrease in stromal ulcer area per day after onset of treatment was almost identical between the groups, and no significant difference in time to fluorescein negativity was found. Conclusions We consider CXL a possible useful adjunct treatment of corneal stromal ulcers in horses, especially for melting ulcers and as a potential alternative to prophylactic antibiotic treatment for noninfected stromal ulcers. However, CXL should not be used alone for infected or suspected infected stromal ulcers, because topical antibiotics were required in all horses with proven infectious keratitis.

Melting corneal ulcers (keratomalacia) in dogs: A 5‐year clinical and microbiological study (2014–2018)

“…12,[17][18][19][20] If the process of keratomalacia fails to stabilize, the ulcer may deepen rapidly, necessitating surgical treatment in the form of conjunctival or corneal grafting in order to provide tectonic support. More recently several groups have described corneal crosslinking (CXL) as an adjunctive therapy for the treatment of melting keratitis in dogs, cats, and horses [21][22][23][24] but more studies are needed to confirm its safety and efficacy.…”

In vitro susceptibility of canine corneal bacterial pathogens to three cross‐linking protocols

“…Corneal cross‐linking (XL) is a non‐surgical, photodynamic therapy which can be used as an adjunctive treatment to medical treatment in corneal ulceration and melting keratitis 7–9,12–14 . XL involves the use of a focused ultraviolet A (UVA) light emitted by a XL system focused onto the cornea following the topical application and saturation of the cornea with riboflavin (vitamin B2) 15 .…”

“…XL has been used successfully for treatment in cases of infectious and non‐infectious melting keratitis in canine and feline patients and for ulcerative keratitis in equine patients 7–9,12–14 . In horses, XL has been demonstrated to be effective as a sole treatment in selected cases of non‐infectious ulcerative keratitis 13 .…”

Features of the clinical picture of keratitis in horses with different forms of the course of the disease

“…The morphometric criteria include the shape of the cornea (sphericity and asphericity). Changes in corneal parameters can lead to visual impairment ( Hellander-Edman et al , 2019 ). The vulnerability of the cornea is determined by the fact that this fibrous component of the eye protrudes forward relative to other eye components, and, therefore, has more opportunities for exposure to traumas and infections ( Kamaev et al , 2012 ; Safonov, 2022a , 2022b ).…”