Eye trauma from a cat scratch with retention of the claw in the anterior chamber in a dog.

Background: Cat scratches and ocular foreign bodies are frequent reasons for consultation in veterinary ophthalmology. Case Description: We here present an unusual case combining trauma to the cornea and lens by a cat scratch with retention of the claw in the anterior chamber. Management consisted of the removal of the claw, reconstruction of the cornea, and mechanized ablation of the lens by phacoemulsification with implantation of an artificial lens. Conclusion: The progression during the follow-up period was considered satisfactory, with positive responses to visual tests and intraocular pressure within the norms. Only dyscoria and a tear of the endothelium and Descemet membrane, secondary to the trauma, remained.

Pyogenic granuloma of the cornea in a pony: Uncommon complication of corneal wound healing.

A 6-year-old miniature Shetland pony mare was referred for evaluation of a left corneal mass, which developed from the healing tissue of a corneal traumatic ulceration that had occurred 4 weeks previously. On gross examination, a spherical, smooth-surfaced, and pink-colored lesion of about 1 cm in diameter was protruding from the left palpebral fissure. Ophthalmic examination revealed that it was attached to the scar tissue of the cornea, and that one corpora nigra was adherent to the posterior face of corneal wounded area, without sign of uveitis. The remainder of the ophthalmic examination was unremarkable. The mass was excised, and cryotherapy was used as an adjunctive therapy. Histopathology of the resected mass was consistent with a pyogenic granuloma on the basis of radially oriented proliferating capillaries, embedded in immature granulation tissue containing an infiltrate of neutrophils, plasma cells and eosinophils. There were no histological features of malignancy. 2 months after surgery, the ventral part of the fibrotic corneal scar was slightly raised by a pink tissue, suggesting possible recurrence of the initial lesion. A second cryotherapy was performed over the leukoma area. No recurrence has been noted for a follow-up period of more than 25 months. Pyogenic granuloma is a benign proliferative fibrovascular response that typically develops after trauma or surgery. Corneal involvement is rare in humans, and to the authors' knowledge has never been documented in veterinary ophthalmology.

Effects of commercial amniotic membrane extract on the re-epithelialization time and the early expression of matrix metalloproteinase-9 in cats with experimentally induced corneal ulcers.

OBJECTIVES: To investigate whether a commercially available amniotic membrane extract (AME) can accelerate corneal wound healing and suppress the early expression of MMP-9 in the tears of cats with experimentally induced superficial ulcerative keratitis. PROCEDURES: A total number of 16 cats were included. At the end of keratectomy, cats in the treatment group (TG, n = 8) received 40 µl of AME (EyeQ® Amniotic Eye Drops, Vetrix®) four times daily, while cats in the control group (CG, n = 8) received 40 µl of saline at the same time points. Tears were collected 24 and 48 h after keratectomy, and the total MMP-9 was quantified by ELISA. RESULTS: The corneal re-epithelialization rate did not differ between groups (p = .26), being 0.48 ± 0.05 mm2 /h in the CG and 0.41 ± 0.03 mm2 /h in the TG. Similarly, the average time to achieve corneal wound healing did not differ between groups (p = .25) and was 61.50 ± 3.54 h in the CG and 70.50 ± 6.71 h in the TG. The dimensions of the ulcerated areas also did not differ at any time point between the groups (p > .05). In both groups, corneas healed without scarring, pigmentation, or vascularization. The expression of MMP-9 in the tears was similar in both groups at 24 h post-keratectomy, with a slight decrease at 48 h (p > .05). CONCLUSIONS: The instillation of a commercial AME (EyeQ®) is safe, but it did not decrease the corneal re-epithelialization time or the early expression of MMP-9 in the tears of cats with experimentally induced superficial ulcerative keratitis in this study.

Corneal diamond burr debridement for superficial non-healing corneal ulcers in cats.

OBJECTIVE: To describe the clinical outcomes and efficacy of diamond burr debridement (DBD) treatment for corneal ulceration in cats. PROCEDURE(S): Medical records of cats that received DBD at two private practices between 2015 and 2021 were retrospectively reviewed. DBD was performed using a battery-powered, handheld motorized burr and a bandage contact lens was placed in 18/21 eyes. Corneal ulceration was considered resolved if the cornea was fluorescein negative with a stable epithelial surface. Recurrence was defined as return of corneal ulceration. Descriptive statistics and a Fisher's exact test were conducted on the study population. RESULTS: Twenty-one eyes from 20 cats with superficial corneal ulcers refractory to medical treatment underwent DBD. Domestic and Burmese were the most commonly encountered breeds and the median age of affected cats was 8.83 years (range 0.5-20 years). Corneal ulceration was present for a median of 14 days prior to DBD. Healing was achieved in 81% of eyes; with four eyes failing to heal and requiring further intervention. Corneal sequestrum was reported in one case that failed to heal. Of the healed cases, three cases recurred (17.6%) at a mean of 116.3 days (range 79-135 days). Burmese were overrepresented (p < .001) in cases that failed to heal or recurred (6/7 eyes; 85.7%). The median postoperative follow-up time was 93 days (range 6-1613 days). CONCLUSIONS: Diamond burr debridement is a safe, non-invasive treatment for corneal ulceration in cats but, compared with published results, it had a lower success rate than superficial lamellar keratectomy.

A prospective, masked, randomized, controlled superiority study comparing the incidence of corneal injury following general anesthesia in dogs with two methods of corneal protection.

OBJECTIVE: To compare the incidence of corneal injury during general anesthesia (GA) and the immediate post-operative period in eyes protected with topical ocular lubricant alone with eyes protected with topical lubricant followed by complete eyelid closure using tape. ANIMALS STUDIED: One hundred client-owned dogs (200 eyes) undergoing GA for MRI scan. METHODS: Patients had ocular lubricant applied to both eyes upon induction of anesthesia. One eye was taped closed immediately after induction for the duration of anesthesia using Strappal® tape (BSN medical™; treatment group), and the other eye was not taped (control group). Eyes were randomly allocated to a treatment group. Ophthalmic examination was performed before and after anesthesia; the examiner was masked to eye treatment groups. Corneal injury was defined as corneal ulceration or corneal erosion. A McNemar's test was used to compare the incidence of corneal injury between groups. A paired-samples t-test was used to compare Schirmer-1 tear test (STT-1) readings between groups. RESULTS: Sixteen eyes (8%) developed corneal erosion. No corneal ulceration occurred. There was no significant difference between incidence of corneal erosion between groups (p = .454). There was a significant decrease in STT-1 readings following GA in both groups (p < .001), with no significant difference in STT-1 between groups (p = .687). No adverse effects of taping the eye closed were observed. CONCLUSION: Taping the eyes closed during GA had no additional benefit to the lubrication protocol used in this study.

Interleukin-6 and lactate dehydrogenase expression in a novel ex vivo rocking model of equine corneal epithelial wound healing.

PURPOSE: To establish a physiologically relevant ex vivo model of equine corneal epithelial wound healing. METHODS: Fourteen equine corneas were randomly assigned to one of two groups: wounded (n = 8) or unwounded (n = 6) controls. In the wounded group, the axial corneal epithelium was removed by applying a 6 mm filter paper disk soaked in 1N-NaOH for 60 s. Corneas were subsequently cultured using an air-liquid interface model. Evaluation of corneal healing was performed daily, and culture medium was collected. Corneas were randomly assigned to undergo processing via histopathology and RNAscope in situ hybridization for interleukin-6 (IL-6) and alpha-smooth muscle actin (αSMA) expression at T24, T48, and T72 h after wounding. Media of the cultured corneas were evaluated for the presence of lactate dehydrogenase (LDH) by a colorimetric assay. RESULTS: The ulcerated area of the wounded corneas decreased over time and all corneas healed within 72 h. Histologically, normal corneal architecture was observed including healthy epithelium (in areas other than the ulcerated ones), minimal stromal edema, intact endothelium, and Descemet's membrane. IL-6 expression was increased in wounded corneas compared with unwounded controls. LDH expression was elevated for both wounded and unwounded corneas at T24 but decreased substantially and was not detected at T48 in media from wounded and unwounded corneas, respectively. No αSMA expression was detected from either wounded or unwounded corneas. CONCLUSIONS: The equine air-liquid interface, ex vivo, corneal epithelial wound healing model is effective and physiologically relevant. This model can be used in future studies evaluating various corneal therapies.

Ocular Surface Disease in Reptiles.

In this article, ocular examination techniques are reviewed in the context of the reptilian patient. Subsequently, ocular surface anatomy and diseases are discussed. Sections for 4 of the 5 Reptilia orders are included: lizards, chelonians, crocodilians, and snakes. Literature pertaining to both wild and captive animals is included.

Corneal abrasion and microbial contamination in horses following general anaesthesia for non-ocular surgery.

OBJECTIVE: To evaluate the incidence of corneal abrasions/ulceration and microbial contamination in horses undergoing general anaesthesia. STUDY DESIGN: Prospective, observational, clinical study. ANIMALS: A total of 40 client-owned healthy horses scheduled for elective non-ophthalmic procedures. METHODS: Conjunctival sac swabs were taken, fluorescein dye applied and digital images recorded from both eyes of the horses after preanaesthetic medication and 24 hours after recovery from general anaesthesia. A paraffin-based bland ophthalmic ointment was applied on the ocular surface intraoperatively following collection of a sample into a sterile container. All samples underwent aerobic, anaerobic and fungal culture. Subject demographics, chronology of ophthalmic ointment use, anaesthesia duration, recumbency after induction, during surgery and recovery, fluorescein uptake and culture results were recorded. Descriptive statistics were performed. RESULTS: Complete data were collected from 34 horses; six (17.6%) developed mild unilateral generalized fluorescein uptake consistent with corneal abrasions. Recumbency on the operating table was the only risk factor significantly associated with corneal abrasions. A total of 11 bacterial species were identified; Staphylococcus spp. (15 eyes) and Micrococcus spp. (eight eyes) were the most frequently isolated bacteria. Two fungal species were isolated postoperatively (Aspergillus spp., Saccharomyces spp.) in two eyes. Ointment contamination was recorded in two cases (5%) but cross-contamination was not recognized. CONCLUSIONSAND CLINICAL RELEVANCE: Incidence of corneal abrasion/ulceration in horses undergoing general anaesthesia and contamination rate of ophthalmic solutions are similar to those previously reported in dogs.

Corneal Response to Injury and Infection in the Horse.

This article describes the natural responses of the immune system and the cornea to injury and infection. The process of reepithelialization and reformation of stromal collagen is discussed, as are the clinical signs and manifestations of the effects of the healing response when it is routine and when it is pathologic. Excessive inflammatory or immune responses by host tissues can cause further damage that may be present from the antecedent injury or the effect of a pathogen. The clinical signs and manifestations of wound healing as well as potential therapeutic interventions are described.

Heat-shock protein 70 expression in the equine cornea.

OBJECTIVE: Expression of the 70-kDa heat-shock protein (HSP70) has been demonstrated in normal canine corneal epithelium, and inducible expression has been suggested to facilitate wound resolution through organized migration, proliferation, and adhesion of the corneal epithelial cells. Diminished expression of HSP70 may therefore contribute to prolonged healing in the pathologic cornea of other companion animal species, including the horse. ANIMAL STUDIED: Normal and pathologic equine cornea was evaluated to determine whether the expression of HSP70 is correlated with appropriate corneal epithelial wound healing. PROCEDURES: Paraffin-embedded tissue from normal equine cornea and therapeutic keratectomies of sterile keratopathies was subject to routine immunohistochemistry for HSP70. RESULTS: Normal equine corneas exhibited the baseline expression of HSP70 in the nuclei of all epithelial cells as well as the cytoplasm of the basal epithelium. Expression of HSP70 in suspected immune-mediated keratitis was localized to the cytoplasm of basal epithelial cells and nuclei of all epithelial cells, similar to the normal equine cornea. Expression in indolent ulcers was diminished; weak, diffuse staining was noted in the cytoplasm of all epithelial cells. CONCLUSIONS: These findings suggest the expression of HSP70 is induced in the normal equine cornea during re-epithelialization and may be altered in sterile keratopathies.

Outcome of phacoemulsification following corneal and lens laceration in cats and dogs (2000-2010).

OBJECTIVE: To investigate the success rate of phacoemulsification following corneal and lens laceration in dogs and cats. PROCEDURE: Retrospective review of cats and dogs presenting with corneal and lens laceration and treated with phacoemulsification. RESULTS: The records of 33 patients (33 eyes: six feline, 27 canine) presenting to a private referral center were reviewed. Affected dogs were younger (median 18 months) than affected cats (median 30 months). The lacerations were caused by cat scratch trauma (9/33), thorn injury (6/33), and glass shards (1/33); the cause was unknown in 17/33 cases. All cats and 85.2% of all dogs were visual at the last examination. The median follow-up was 4 and 8 months for cats and dogs, respectively. In all canine cases that developed vision loss, this occurred within the first 14 weeks postoperatively. The ultimate cause for vision loss in dogs was secondary glaucoma (4/4) and retinal detachment (1/4). CONCLUSION: Cats have an excellent outcome and dogs a very good outcome following surgery for corneal and lens laceration. The cause of the trauma, the size of the lesion, the time interval between the ocular trauma and surgery, and the type of surgery were not found to have an influence on the outcome of patients in this study. We postulate that vision loss might develop more often in cases with complications associated with the initial corneal laceration wound.

Corneal and anterior segment foreign body trauma in dogs: a review of 218 cases.

OBJECTIVES: To review clinical data on dogs that suffered a corneal and anterior segment foreign body (CASFB) trauma and to determine the risk factors for foreign body (FB) trauma and subsequent enucleation. ANIMALS STUDIED: Dogs with CASFB presented to the Animal Health Trust (AHT) from January 2000 to December 2012. PROCEDURES: Clinical data for CASFB cases were compared to those available for the remaining AHT ophthalmic population over the same period. The depth of the FB trauma was divided into five categories. The type of FB and method of removal were described for each category. The degree of secondary uveitis and lens involvement was graded and correlated with subsequent enucleation. RESULTS: The mean age (standard deviation) of 218 identified CASFB cases was 3.96 (2.95) years. Risk factors for CASFB trauma were dogs younger than 5 years, English Springer Spaniels, Labrador Retrievers, and working dogs. Most dogs required general anesthesia for FB removal, and hypodermic needles were the most commonly used instrument. The lens was involved in some cases with a full-thickness CASFB trauma (n = 49, 45%), but most suffered a minor lens trauma (n = 37, 76%). The lens trauma and phacoclastic uveitis were managed medically in most dogs (n = 37, 76%), and phacoemulsification was only elected as initial treatment in some dogs (n = 10, 20%). Enucleation was required overall in 6% of dogs. Statistically significant associations were found between enucleation and depth of FB trauma, degree of uveitis, and severity of lens trauma (P < 0.001). CONCLUSIONS: Young dogs, English Springer Spaniels, Labrador Retrievers, and working dogs had an increased risk of CASFB trauma. Risk factors for enucleation were full-thickness FB penetration, severe lens trauma, and severe uveitis.

Heat-shock protein expression in canine corneal wound healing.

OBJECTIVE: Heat-shock proteins, particularly the 70-kDa member (Hsp70), have been implicated in facilitating wound healing in multiple tissues. Expression and localization of three HSPs were assessed in normal and wounded canine corneas to elucidate a role in epithelial healing. METHODS: Paraffin-embedded normal corneas, acute and repeatedly abraded corneas, and keratectomies of spontaneous chronic corneal epithelial defects (SCCEDs) were subjected to routine immunohistochemistry for Hsp27, 47, and 70 expression. Ex vivo corneal defects were created and treated with anti-HSPs or IgG controls, and wound healing was monitored. Primary cultures of canine corneal stromal fibroblasts and corneal epithelial cells were treated with exogenous Hsp70, and an artificial wound was created in vitro to monitor restoration of the monolayer. RESULTS: Normal canine corneas exhibited constitutive expression of all HSPs evaluated. Inducible expression was demonstrated in acutely wounded tissues, and expression in the chronically abraded corneas was relocalized. All HSP expression was below the limits of detection in the epithelium of SCCED samples. Inhibition of HSPs in culture resulted in delayed wound healing when compared to controls. Hsp70-treated fibroblasts demonstrated significantly (P < 0.001) increased migration and proliferation compared to the vehicle control; however, there was no significant effect of exogenous Hsp70 on corneal epithelial cells. CONCLUSIONS: These findings suggest that HSPs are induced in the normal canine cornea during re-epithelialization. Hsp70 expression is likely important for inducing the cytoarchitectural remodeling, migration, and proliferation necessary early in the canine corneal healing response, and suppressed expression may contribute to the pathophysiology of nonhealing defects.

Expressão de metaloproteinases de matriz e PCNA em úlceras de córnea profundas, induzidas em coelhos, tratadas com plasma rico em plaquetas / Expression of matrix metalloproteinases and PCNA in deep corneal ulcers induced in rabbits, treated with platelet-rich plasma

O objetivo deste estudo foi avaliar a influência do plasma rico (PRP) e pobre (PPP) em plaquetas na proliferação celular e expressão de metaloproteinases de matriz (MMPs), durante a reparação de úlceras corneais profundas. Foram utilizadas 45 coelhas, distribuídas em 3 grupos (G) experimentais (n=15), designados como grupos PRP (GR), PPP (GP) e Controle (GC), de acordo com o tratamento. Todos os animais foram submetidos à indução cirúrgica unilateral de úlcera corneal. No GR e GP, o sangue autólogo foi centrifugado, utilizando-se protocolo padronizado, e foram confeccionados os colírios de PRP e PPP, e instilados cinco vezes ao dia. No GC, foi utilizado colírio lubrificante. Cada grupo foi subdividido (n=5), segundo o momento final de avaliação, sendo 4 (M4), 7 (M7) e 30 dias (M30). As córneas dos animais foram processadas para avaliação morfológica e imuno-histoquímica para PCNA, MMP1, MMP2, MMP9, MT1-MMP e TIMP1. No M4, os níveis de MMP2 foram maiores no GP e GR, sendo que, no M7, esse comportamento foi observado apenas no GP. No M30, no GR, verificou-se maior número de células epiteliais e marcação para MMP1 que o GP. No GR, a proliferação celular foi maior no M4 que nos demais momentos, e a marcação para MMP2 foi maior no M4 que no M30. O PRP estimula a proliferação celular na fase inicial (M4) do tratamento quando comparado aos demais momentos, diferentemente dos demais tratamentos. O uso de colírios de plasma rico e pobre em plaquetas influencia a expressão de metaloproteinases de matriz envolvidas no processo de reparação corneal.

The aim of this study was to evaluate the influence of platelet-rich (PRP) and poor (PPP) plasma in cell proliferation and matrix metalloproteinases (MMPs) expression during the repair of deep corneal ulcers. Forty-five female rabbits were distributed in 3 experimental groups (G) (n = 15), referred to as PRP (GR), PPP (GP) and Control (GC) groups, in accordance with the treatment. All animals underwent surgical induction of unilateral corneal ulcer. PRP and PPP eye drops were made by using centrifuged blood through standardized protocol, and instilled five times a day. In GC, lubricant eye drops were used. Each group was subdivided (n = 5) according to the final time point, 4 (M4), 7 (M7) and 30 days (M30). The animals' corneas were processed for morphological and immunohistochemical analysis for PCNA, MMP1, MMP2, MMP9, MT1-MMP and TIMP1. In M4, the levels of MMP2 were higher in GP and GR, and in M7, this behavior was only observed in the GP. In M30, more epithelial cells and MMP1 expression were found in GR than GP. In GR, cell proliferation was higher in M4 than at other time points and MMP2 expression was higher in M4 than M30. The PRP stimulates cell proliferation in the early phase (M4) of treatment when compared to other time points, different from other treatments. The use of eye drops of platelet-rich and poor plasma influences the expression of matrix metalloproteinases involved in the corneal repair process.

Corneal Emergencies.

Corneal emergencies can be due to a number of different causes and may be vision threatening if left untreated. In an attempt to stabilize the cornea, it is of benefit to place an Elizabethan collar on the patient to prevent further corneal damage. This article discusses the diagnosis, prognosis, and management of corneal emergencies in dogs and cats.

Therapeutic potential of Pirfenidone for treating equine corneal scarring.

OBJECTIVE: To evaluate the safety and efficacy of Pirfenidone (PFD) in the treatment of equine corneal fibrosis using an in vitro model. METHODS: Healthy donor equine corneas were collected and used to generate primary equine corneal fibroblasts (ECFs) by growing cultures in minimal essential medium supplemented with 10% fetal bovine serum. Equine corneal myofibroblasts (ECMs), used as a model of equine corneal fibrosis, were produced by growing ECF cultures in serum-free medium containing transforming growth factor ß1 (1 ng/mL). Trypan blue viability assays and changes in ECF morphology were utilized to determine the optimal PFD dose for this in vitro model. Trypan blue viability, phase-contrast microscopy, and TUNEL assays were used to evaluate the cytotoxicity of PFD. Scratch and MTT assays were used to evaluate the effect of PFD on cellular migration and proliferation. Real-time PCR, immunoblot analysis, and immunocytochemistry were employed to determine the efficacy of PFD to inhibit ECM formation in vitro. RESULTS: Topical PFD application at 200 µg/mL successfully decreased αSMA expression when compared to the TGFß1 only treatment group (P < 0.01). PFD application ≤ 200 µg/mL did not affect ECF phenotype or cellular viability and did not result in significant cytotoxicity. CONCLUSIONS: Pirfenidone safely and effectively inhibits TGFß1-induced equine corneal fibrosis in vitro. In vivo studies are warranted.

Outcome of conjunctival flap repair for corneal defects with and without an acellular submucosa implant in 73 canine eyes.

OBJECTIVE: To report and compare the success rate of a conjunctival pedicle flap (CPF) alone vs. a CPF with an underlying acellular submucosa implant for the repair of deep or perforating corneal wounds in dogs. PROCEDURES: Records of 69 dogs (73 eyes) receiving a CPF with or without an acellular submucosa implant between 2004 and 2012 were reviewed. Successful outcome was defined as a comfortable eye with vision at the last post-operative evaluation. Age, breed, underlying corneal disease, surgical time, lesion characteristics, topical therapies, and postoperative complications were investigated. RESULTS: Groups consisted of dogs that had a CPF alone (n = 37) and dogs that had a CPF plus an acellular submucosa implant (n = 36). Age, lesion size, surgical time, and time to discontinuation of topical anti-proteolytic medications was not significant between groups. Topical antibiotic use was terminated 13 days sooner (P ≤ 0.01) in dogs with an acellular submucosa implant. The combined success rate of all corneal wounds was 93% with success rate of corneal perforations, descemetoceles, and deep stromal wounds being 89%, 95%, and 100%, respectively. There was no difference in overall success rate between groups. Increasing age was associated with a negative outcome (P ≤ 0.01). Lesion size, presence of a corneal perforation, and concurrent keratoconjunctivitis sicca was not associated with a negative outcome. CONCLUSIONS: A comparable success rate is achieved for deep or perforating corneal wounds stabilized with a CPF alone vs. a CPF plus acellular submucosa. Glaucoma, persistent uveitis, and cataract formation were not reported as post-operative complications in this study population.

Suberoylanilide hydroxamic acid (vorinostat): its role on equine corneal fibrosis and matrix metalloproteinase activity.

OBJECTIVE: To explore the effect of suberoylanilide hydroxamic acid (SAHA) (i) on corneal fibroblast differentiation, morphology, and viability; and (ii) on the expression levels of matrix metalloproteinases (MMPs) 2 and 9 using an in vitro model of equine corneal fibrosis. PROCEDURE: Healthy donor corneas were used to generate primary cultures of equine corneal fibroblasts. The fibroblasts were exposed to 5 ng/mL TGFß1 to induce myofibroblast formation. The cultures were treated with either 5 µm or 10 µm SAHA for 72 h in the presence of TGFß1. Real-time PCR and immunocytochemistry were used to determine the antifibrotic efficacy of SAHA by quantifying α-smooth muscle actin (αSMA), a marker of myofibroblast formation and fibrosis. Real-time PCR was used to determine the effects of SAHA on MMP2 and MMP9 expression. Cytotoxicity of SAHA was evaluated with phase contrast microscopy and trypan blue exclusion assays. RESULTS: Suberoylanilide hydroxamic acid (SAHA) significantly attenuated TGFß1-induced differentiation of equine fibroblasts to myofibroblasts as indicated by 3- to 3.5-fold (P < 0.001) decrease in αSMA mRNA and 86-88% (P < 0.001) decrease in αSMA+ immunocytochemical staining. SAHA treatment also resulted in 4.5- to 5.5-fold (P < 0.01) decrease in MMP9 expression. A dose-dependent bimodal effect of SAHA on MMP2 expression was noted (3.5-fold increase with 5 µm dose; 0.5-fold decrease with 10 µm dose). No change in fibroblast viability was observed with a 5 µm SAHA dose, whereas a 10 µm dose resulted in a moderate 17% decrease in cell viability. CONCLUSIONS: Suberoylanilide hydroxamic acid (SAHA) can effectively inhibit TGFß-induced differentiation of equine corneal fibroblasts to myofibroblasts and modulates MMP production in vitro.