Effects of corneoconjunctival transposition, posterior lamellar keratoplasty and modified deep lamellar endothelial keratoplasty on streak retinoscopy in equine cadaver eyes.

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.

A comparison between dehydrated and cryopreserved heterologous corneal grafts for penetrating keratoplasty in dogs and cats.

OBJECTIVE: To compare the efficacy of dehydrated and cryopreserved heterologous corneal grafts in the management of full-thickness corneal defects in cats and dogs. ANIMALS STUDIED: Sixty-five cats (81 eyes) and 42 dogs (51 eyes) with full-thickness corneal defects of different origin. MATERIALS AND METHODS: This prospective randomized trial included 132 animal eyes (81 feline and 51 canine) with different full-thickness corneal defects. Penetrating keratoplasty with cryopreserved and dehydrated corneal grafts was performed in 57 and 75 eyes, respectively. Follow-up lasted for 6 months. RESULTS: Optically clear cornea with mild scarring was achieved in 40.4% of cases (23/57 eyes) after cryopreserved and in 42.7% of cases (32/75 eyes) after dehydrated corneal grafting. Moderate scarring after cryopreserved and dehydrated corneal grafting was observed in 35.1% of cases (20/57 eyes) and 37.3% of cases (28/75 eyes), respectively. Severe scarring and corneal opacities with severe vision loss after cryopreserved and dehydrated corneal grafting developed in 22.8% of cases (13/57 eyes) and 18.7% of cases (14/75 eyes), respectively. In two groups of animals combined, the affected eyes were salvaged and visual function improvement of varying degree was achieved in 78.0% of cases (103/132 eyes). Transplant rejection warranted enucleation in 1.75% of cases (1/57 eyes) and 1.3% of cases (1/75 eyes) after cryopreserved and dehydrated corneal grafting, respectively. CONCLUSIONS: No statistically significant differences in clinical outcomes of penetrating keratoplasty with cryopreserved and dehydrated corneal grafts were observed. Dehydrated cornea may be considered a viable alternative to cryopreserved grafts for the management of full-thickness corneal defects.

The use of acellular porcine corneal stroma xenograft (BioCorneaVet™ ) for the treatment of deep stromal and full thickness corneal defects: A retrospective study of 40 cases (2019-2021).

OBJECTIVE: To document the effectiveness and outcome of corneal grafting using acellular porcine corneal stroma (APCS) for veterinary use (BioCorneaVet™ ) to restore corneal integrity in dogs. METHODS: A review of medical records of patients that underwent keratoplasty with APCS graft to repair deep corneal defects, descemetoceles, and perforations between 2019 and 2021 was carried out. Only animals with intact dazzle reflex, consensual PLR before the surgery and a minimum follow-up of four weeks were considered for the study, with forty dogs (1 eye each) meeting the inclusion criteria. RESULTS: Brachycephalic breeds were the most frequently represented, and 20 right eyes and 20 left eyes were affected with 25 perforations, 8 descemetoceles, and 9 deep stromal defects (1 eye had both perforation and descemetocele). Most of the patients had concurrent ocular diseases or had undergone previous surgery on the other eye. Two different thickness of xenograft was used (300 or 450 µm), and the diameter ranged from 3 to 10 mm. Postoperative complications included mild to severe corneal vascularization, partial dehiscence, melting, and glaucoma. Follow-up time ranged from 28 to 797 days (mean: 233 days). Ocular integrity was maintained in 37/40 cases (92.5%), and vision was preserved in 36 cases (90%). CONCLUSION: The use of APCS (BioCorneaVet™ ) is an effective surgical treatment for deep stromal defects, descemetocele, and perforations in dogs, providing a good tectonic support and preserving anatomical integrity and vision. The cosmetic appearance was considered good in all the cases and continued to improve with time.

Autologous lamellar keratoplasty for the treatment of feline corneal sequestrum: A retrospective study of 35 eyes (2012-2020).

OBJECTIVE: To evaluate the use of autologous lamellar keratoplasty for the treatment of feline corneal sequestrum (FCS). PROCEDURE: The medical records of cats diagnosed with FCS that underwent autologous lamellar keratoplasty between 2012 and 2020 with a minimum of 2 months of follow-up were reviewed. After keratectomy of FCS, a button adjacent to the corneal limbus was harvested on the same eye and sutured to the recipient bed. A nictitating membrane flap was left in place until the first recheck except for one patient. Postoperative treatment with topical and systemic antibiotics and systemic nonsteroidal anti-inflammatory medications was prescribed. Follow-up examinations were carried out 2 weeks, 1 month and 2 months post-operatively and consisted of a complete ophthalmic examination. RESULTS: A total of 35 cats (35 eyes) were included. The median follow-up time was 3.2 months (range, 2-59 months). Brachycephalic cats were overrepresented (85.7%). The mean graft size was 6.5 mm (range, 6-9 mm). Minor complications consisting of melting and partial integration of the graft occurred in 2/35 eyes (5.7%). Recurrence was observed in 1/35 eyes (2.9%) and was managed by a superficial keratectomy. A good visual outcome was achieved in all eyes, and a faint or mild corneal opacification occurred in 15/35 (42.9%). CONCLUSIONS: Autologous lamellar keratoplasty is an effective treatment for FCS, providing good tectonic support to the affected cornea and resulting in good visual and cosmetic outcomes. These results should be verified in future prospective studies that include a larger number of cases and longer-term follow-up.

Corneo-limbo-conjunctival transposition to treat deep and perforating corneal ulcers in dogs: A review of 418 eyes and corneal clarity scoring in 111 eyes.

PURPOSE: To report surgical and corneal clarity scores (CCSs) of corneo-limbo-conjunctival transpositions (CLCTs) in a large number of canine cases. METHODS: Retrospective review of records that underwent CLCT to repair deep ulcers or perforations between 2002 and 2018. Signalment, concurrent eye disease, additional procedures, pathogenesis, medication, graft orientation, follow-up, and CCSs were recorded. RESULTS: 418 eyes of 399 dogs were included. Brachycephalics were most commonly affected, comprising 325/418 (77.75%) of the eyes. The most commonly affected breeds were Pugs, Shih Tzus, Cavalier King Charles Spaniels, and French Bulldogs, with 116/418 (27.75%), 64/418 (15.31%), 34/418 (8.13%), and 34/418 (8.13%) ulcerated eyes, respectively. Mean age at surgery was 5.5 years (range 59 days-17.7 years), and median follow-up time was 100 days (range 3 days-7.64 years). The most common etiopathogenesis was spontaneous ulceration in 205/418 eyes (49.04%) of which 191 (93.17%) occurred in brachycephalics. Primary keratoconjunctivitis sicca affected 122/418 eyes (29.19%) and injury 39/418 eyes (9.33%). Mean ulcer width was 3.5 mm (0.5-10 mm). Success rate was 97.13% (406/418 eyes). Failure end points recorded included no menace response, secondary glaucoma, and endophthalmitis. Pre-existing perforation was found in 101/418 (24.16%) of the eyes and significantly increased failure rate (P < .001). The median CCS was G3 (G0-G4), which was lower for Pugs (G2). Graft orientation affected CCS, but did not reach statistical significance. CONCLUSION: The high success rate and CCS for CLCT in dogs make it a good technique to treat deep ulcers but a less desirable outcome is anticipated when treating perforations and Pugs.

Corneoconjunctival transposition for the treatment of deep stromal to full-thickness corneal defects in dogs: A multicentric retrospective study of 100 cases (2012-2018).

OBJECTIVE: To describe and evaluate the use of corneoconjunctival transposition (CTT) as a surgical treatment for canine deep stromal ulcers, descemetoceles, and full-thickness corneal defects and to determine its efficacy in preserving corneal graft transparency and vision. ANIMALS STUDIED: One hundred client-owned dogs with deep stromal ulcers, descemetoceles, or full-thickness corneal defects. METHODS: Medical records of canine patients that underwent CCT, from 2012 to 2018, were reviewed. Only, patients with preoperative positive consensual pupillary light and dazzle reflexes were included. RESULTS: There were 59 males and 41 females, from 0.3 to 17 years. Brachycephalic breeds were overrepresented (65%). All patients were unilaterally affected, with 16 deep stromal ulcers, 33 descemetoceles, and 51 corneal perforations, of a median (range) size of 4 (2-8) mm. The central cornea was affected in the majority of cases (57%), and euryblepharon and keratoconjunctivitis sicca were the most common concurrent ocular diseases (42% and 40%, respectively). The graft was most frequently harvested from dorsal (67%), and 9/0 absorbable suture material was used. Intraoperative and postoperative complications were seen in 7 and 21 cases, respectively. Mean follow-up time was 107.8 days. Vision was preserved in 96% patients, with 62% showing faint to mild opacification. Among the statistically analyzed variables, euryblepharon and pigmentary keratitis were found to be significantly associated with greater corneal graft opacification (P = .040 and P = .028, respectively). CONCLUSIONS: Corneoconjunctival transposition is an effective surgical treatment for deep stromal, descemetocele, and full-thickness corneal defects in dogs, achieving a highly satisfactory degree of corneal graft transparency and preserving vision.

Endothelial keratoplasty for corneal endothelial dystrophy in a dog.

OBJECTIVE: To assess the efficacy of an endothelial keratoplasty procedure at defined intervals to 1 year postoperatively for the treatment of corneal endothelial dystrophy (CED) in a canine patient. PROCEDURE: A dog diagnosed with CED with progressive corneal edema underwent an endothelial keratoplasty. The patient was examined pre- and postoperatively with slit lamp biomicroscopy and ultrasonic pachymetry. RESULTS: Mean central corneal thickness (CCT) measured with pachymetry was >1400 µm preoperatively and decreased postoperatively to 725 µm. The transplanted donor tissue became transparent 2 weeks postoperatively and incorporated with the recipient cornea. The graft remained transparent throughout the duration of the postoperative period evaluated in this study (2 weeks postoperatively to 1 year). The canine patient was comfortable pre- and postoperatively. CONCLUSIONS: Endothelial keratoplasty is a potential therapeutic option for canine cases with progressive corneal thickening due to CED. As this is a single case study, further investigation into the use of endothelial keratoplasty to treat CED is warranted. Moreover, canine patients with CED might serve as a surgical model for human patients with Fuchs' Endothelial Corneal Dystrophy.

A bidirectional corneoconjunctival transposition for the treatment of feline corneal sequestrum.

A case is presented of a 1-year-old Persian cat with a corneal sequestrum treated with a bidirectional corneoconjunctival transposition. The size of this lesion precluded use of a traditional corneoconjunctival transposition. At the time of writing, the patient maintained a clear visual axis with minimal scarring and no recurrence 6 months post-operatively. This report describes a novel surgical technique used to successfully treat a large feline corneal sequestrum.

Corneal grafting for the treatment of full-thickness corneal defects in dogs: a review of 50 cases.

OBJECTIVE: To describe corneal grafting for the treatment of full-thickness corneal defects in dogs and to determine its effectiveness in preserving vision. METHODS: A review of the medical records of dogs that underwent corneal grafting following corneal perforations (≥3 mm) at the VTH-UAB from 2002 to 2012 was carried out. RESULTS: Fifty dogs of different breed, age and gender were included. Brachycephalic breeds were overrepresented (37/50;74%). All cases were unilateral, with euryblepharon being the most common concurrent ocular abnormality (20/50;40%). Full-thickness penetrating keratoplasties (FTPK) were performed in 21/50 eyes (42%) and lamellar keratoplasties (LK) in 29/50 eyes (58%). Frozen grafts (FroG) were used in 43/50 eyes (86%) and fresh homologous grafts (FreHoG) in 7/50 (14%). Of the former group, 26 were homologous (FroHoG:60%) and 17 heterologous (FroHeG:40%). A combination of topical medication (antibiotics, corticosteroids, cycloplegics, and 0.2% cyclosporine A) and systemic mycophenolate mofetil was administered. Median follow-up time was 200 days. Postsurgical complications included wound dehiscence (6/50;12%) and glaucoma (4/50;8%). Clinical signs of graft rejection were diagnosed as follows: FroHoG (13/26;50%), FroHeG (11/17;65%), FreHoG (4/7;57%), FTPK (12/21;57%), and LK (16/29;55%). Medical treatment successfully controlled graft rejection in 11/28 eyes (39%). Good anatomical outcome was achieved in 86% (43/50), of which 95% (41/43) were visual at last examination, with moderate opacification to complete transparency of the graft present in 48.2%. CONCLUSIONS: Corneal grafting is an effective surgical treatment for full-thickness corneal defects in dogs. If graft rejection is present, additional medical or surgical therapy may be necessary, achieving a highly satisfactory visual outcome.

Feline corneal sequestra: outcome of corneoconjunctival transposition in 97 cats (109 eyes).

Case series summary A retrospective study was undertaken to review outcomes of keratectomy and corneoconjunctival transposition in cats with superficial and deep corneal sequestra. Information including pertinent history, signalment, ophthalmological findings and postoperative outcome was collected from medical records. Follow-up was obtained by clinical examination, contact with the referring veterinarians and review of medical records or telephone contact with owners. Ninety-seven cats (109 eyes) were included from 2005-2015. The most commonly affected breeds included Persian, Burmese and Himalayan. The mean age at the time of surgery was 6.8 years (median 6.5 years; range 8.0 months-18.0 years). A corneal sequestrum in the contralateral eye was diagnosed in 28 cats (28.9%). Recurrent corneal sequestration was diagnosed in eight cats (nine eyes), with recurrence occurring a mean of 703 days after surgery (range 29-1750 days). Age, sex, breed, depth of sequestration and concurrent ocular disease in the contralateral eye were compared between cats with and without recurrence, with no risk factors for recurrence identified. Relevance and novel information Excellent surgical outcomes have previously been described in a series of 17 cats with superficial and mid-stromal corneal sequestra. This paper adds further information to the literature by describing a larger series of cats, with corneal sequestra affecting the full range of corneal thickness, and good long-term postoperative outcomes.

Porcine urinary bladder extracellular matrix grafts (ACell Vet® Corneal Discs) for keratomalacia in 17 equids (2012-2013).

OBJECTIVE: To describe the clinical course, outcomes, and complications associated with use of commercially available porcine urinary bladder extracellular matrix (ECM) grafts (ACell Vet(®) Corneal Discs) in equid patients with keratomalacia, and to evaluate the efficacy of ECM grafts as a viable alternative to other biomaterials for corneal grafting in equid patients. ANIMALS: Sixteen horses and one donkey (17 eyes) with unilateral keratomalacia severe enough to warrant surgical repair between August 2012 and September 2013. PROCEDURE: Retrospective medical record review to identify equid patients meeting inclusion criteria of (i) diagnosis with keratomalacia severe enough to warrant surgical repair and (ii) surgical repair with an extracellular matrix graft. RESULTS: Eleven geldings, four mares, and two colts met inclusion criteria. Patients averaged 9 years of age. Twelve of 17 eyes (71%) were considered infected based on either corneal cytology (10/17, or 59%) or corneal culture (12/17, or 71%) positive for bacteria (8/17, or 47%) or fungi (9/17, or 53%). At the time topical medications were discontinued, 16 eyes (94%) were visual. One operated eye ruptured 5 days postoperatively and was enucleated. Keratouveitis developed in 14/14 eyes that underwent regular examinations approximately 2 weeks postoperatively which responded to systemic nonsteroidal anti-inflammatory drug therapy. CONCLUSIONS: Extracellular matrix grafts may be a viable alternative to other biomaterials for corneal grafting in equids. Advantages include commercial availability and shelf storage.

Deep anterior lamellar keratoplasty of dog eyes using the big-bubble technique.

This study was conducted to establish the feasibility of corneal transplantation using the big-bubble technique (BBT) to perform deep anterior lamellar keratoplasty (DALK) in three dogs. After the cornea was trephined 750 µm, 4 mL of air was injected, and the blanched stroma was removed to expose Descemet's membrane (DM). The donor corneal button, which was gently stripped off the DM, was sutured onto the bare DM of the recipient cornea. The dogs received topical antibiotics every 6 h for 7 days and 2% cyclosporine ointment every 12 h for 1 month. The eyes were examined post-operatively at 7, 14, 21, 28 and 150 days. The central portion of the transplanted cornea stayed transparent while corneal haze developed around the transplanted margin. Menace response was normal even though the transplanted cornea was edematous until 3 weeks after surgery. A marginal haze was rarely observed between the donor and recipient corneas at 150 days after the operation. A spotted haze developed in the central part of the deep stroma near the DM. Upon histopathological examination, the stroma and epithelium of the donor cornea had normal structures. Corneal transplantation using DALK with BBT can be performed in dogs preserving the healthy endothelium.

Lamellar keratoplasty in rabbits using human and rabbit amniotic membrane grafts: a comparative study.

OBJECTIVE: To compare the behavior of human and rabbit amniotic membrane (AM) grafts in surgically induced corneal thinning in rabbits. ANIMALS STUDIED: Thirty two NZWR were randomly assigned to two groups of 16 animals each according to AM type (Human AM: group HAM and Rabbit AM: group RAM). PROCEDURE: All animals were submitted to right keratectomy at a depth of 0.1 mm using a 5 mm trephine. Animals from HAM group had a button of 5 mm of human AM sutured into the corneal bed with a continuous pattern and 10.0 nylon monofilament suture, while animals from the RAM group had a button of 6 mm diameter of rabbit AM. Four animals in each group were euthanized 2, 7, 15, and 30 days postoperatively. Their corneas were harvested, fixed in 2% glutaraldehyde solution, and stained with haematoxylin-eosin, picrosirius red, and alcian blue for evaluation under light optical microscopy. Microscope images were digitalized and inflammatory cells and stromal blood vessels were counted. RESULTS: There were no clinically significant differences between groups, and complete corneal epithelialization was observed in all animals in 30 days. Light optical microscopy revealed AM incorporation and resorption in both groups. However, the number of inflammatory cells and blood vessels was significantly higher in group HAM than in group RAM (P < 0.05, Mann-Whitney test). Clinical responses to human or rabbit AM were similar; however, human AM induced greater inflammatory reaction and stromal neovascularization in the rabbit cornea than in rabbit AM. CONCLUSION: These differences may reflect a potential reaction to the xenograft. More studies are needed to further characterize these findings.

Modified lamellar keratoplasties for the treatment of deep stromal abscesses in horses.

OBJECTIVE: To describe a surgical modification of deep lamellar endothelial keratoplasty (DLEK) and posterior lamellar keratoplasty (PLK) procedures, to facilitate surgery on standing horses under-sedation. ANIMALS STUDIED: Four client-owned horses, for which the owners declined surgery under general anesthesia, underwent standing corneal lamellar keratoplasty procedures for the treatment of deep corneal stromal abscesses. PROCEDURES: All four horses were placed in stocks and sedated with detomidine. Local eyelid and retrobulbar blocks were performed to provide local analgesia and akinesia, and each horse's head was stabilized and supported by soft pads placed on a mobile cart. Deep lamellar endothelial keratoplasties (DLEKs) and posterior lamellar keratoplasties (PLKs) were performed on two horses each, for the treatment of deep stromal abscesses (DSA). Following the first DLEK, a mid-stromal two-step anterior lamellar keratectomy modification was used to facilitate rapid closure of the anterior chamber immediately following removal of the abscess. RESULTS: Each of the four horses had similar cosmetic and postoperative visual outcomes, compared to previously published results. Intra-operative complications were most prevalent in the first DLEK case (i.e., focal iris and lens damage and postoperative anterior chamber collapse) and were all but eliminated in the remaining three cases. Similar to previously reported findings, greater postoperative corneal fibrosis was observed in the DLEK cases. CONCLUSIONS: In horses with deep stromal or endothelial abscesses, for which general anesthesia is not an option, both the modified DLEK and PLK corneal procedures may be performed as an alternative to enucleation on the standing, sedated horse.

Corneal grafting for the treatment of feline corneal sequestrum: a retrospective study of 18 eyes (13 cats).

OBJECTIVE: To determine the clinical outcome of corneal grafting for the treatment of feline corneal sequestrum (FCS). ANIMAL STUDIED: Domestic cats. PROCEDURES: A review of the medical records of cats that underwent keratoplasty as a treatment of FCS at the VTH-UAB, from 2002 to 2012, was carried out. RESULTS: Thirteen cats (18 eyes) of different breed, age, and gender were included. Persian cats were overrepresented (12/13;92%). There were nine males and four females, of a mean age of 3.4 years (0.7-7.1). Ipsilateral chronic corneal ulceration was reported as the most common concurrent ocular disease (6/18;33%). Keratoplasty was performed bilaterally in 5 cats (5/13;38%) and unilaterally in 8 (8/13;62%). Lamellar keratoplasty was performed in 17 eyes (17/18;95%) and full-thickness keratoplasty in 1 (1/18;5%). Mean graft size was 8.3 mm (4-11.5). Fresh homologous graft was performed in 2 eyes (2/18;11%) and frozen graft in 16 (16/18;89%). Of the latter group, homologous graft was performed in 6 eyes (6/16;37.5%) and heterologous in 10 (10/16;62.5%). In all the cats, postoperative treatment included topical antibiotics, corticosteroids, cycloplegics, and 0.2% cyclosporine A. Median follow-up time was 18.2 months, and main postoperative complications were diffuse mild epithelial pigment formation (2/18;11%), graft malacia (1/18;5%), and sequestrum recurrence (1/18;5%). Mean epithelial healing time was 19.2 days. Good visual outcome was achieved in all the eyes (100%), the majority of them having faint or mild corneal opacity (15/18;83%). CONCLUSIONS: Keratoplasty is an effective surgical treatment for FCS. The donor tissue provides excellent tectonic support to the affected corneas, with good visual and cosmetic outcome.

Microbiological profile of donor corneas stored for tectonic transplantation purposes in rabbits / Microbiologia de amostras de bancos de córneas destinadas a transplantes, em coelhos

This study aimed to evaluate the microbiota of donor rabbit corneas stored for tectonic transplantation purposes. Swabs from both corneas of 20 rabbits were carefully collected and submitted to microorganism isolation and identification. After this first swab collection, rabbits were euthanized for reasons other than this project and the eyes were enucleated. The corneas were collected and stored to compose the cornea tissue bank. Corneas were stored in a 0.3% tobramycin solution at -20ºC. After 30 days, the corneas were thawed at room temperature and removed from the antibiotic. New swabs were obtained from the corneas and submitted to microorganism isolation and identification. Gram positive organisms were predominant in the rabbit corneal flora before storage and the Staphylococcus sp. was the most common microorganism isolated from those samples. No growth was observed on the samples collected after storage. The methods used for collection and storage of the corneas were efficient to constitute a sterile donor corneal tissue bank.

Analisaram-se córneas armazenadas para transplantes tectônicos usando-se suabes coletados de 20 coelhos, visando ao isolamento e à identificação de microrganismos. Após a coleta das amostras, os coelhos foram submetidos à eutanásia, por razões alheias ao estudo, e enucleados. As córneas foram coletadas e armazenadas a fim de se constituir o banco de córneas. O armazenamento deu-se em solução de tobramicina 0,3% a -20ºC, por 30 dias. Após esse período, as córneas foram descongeladas à temperatura ambiente e removidas da solução de antibiótico. Novos suabes foram coletados e submetidos ao isolamento e à identificação dos microrganismos. A flora corneal mostrou-se predominantemente composta por bactérias Gram positivas, sendo o Staphylococcus sp. o mais identificado. Não se verificou crescimento de colônias bacterianas ou fúngicas nas amostras após o armazenamento. Considerando-se a maneira como a pesquisa foi concebida e as injunções do meio em que ela foi realizada, há como admitir, pela ausência de crescimento microbiano nas amostras armazenadas, que a técnica de armazenamento empregada é segura para a estocagem de córneas destinadas a transplantes.

Surgical treatment of epibulbar melanocytomas by complete excision and homologous corneoscleral grafting in dogs: 11 cases.

OBJECTIVE: The aim of the study was to evaluate the efficacy, outcome, and complications following penetrating sclerokeratoplasty and frozen homologous corneoscleral grafting for the management of extensive canine epibulbar melanocytomas. METHODS: Medical records of canine patients treated at three different veterinary hospitals between 1999 and 2010 were reviewed. Signalment, location and extent of melanocytomas, recurrence rate, and early and late complications were reported. Patients were re-examined postoperatively to provide follow-up information. RESULTS: Patients included one intact male, three castrated males, six intact females, and one spayed female, with a median age of 5 years (range, 3-9). German Shepherds were overrepresented. Tumors extended from 2 to 4 clock hours at the limbus and up to 17 mm from clear cornea to globe equator. One case showed iridocorneal angle invasion; corneal involvement was present in all cases, and lipid keratopathy was present in four cases. In two cases, there was incomplete resection owing to tumor extent. Follow-up time ranged from 3 to 72 months (median, 17 months), with one case of intraocular tumor progression. Early complications included anterior uveitis (11/11), intracameral fibrin (5/11), hyphema (4/11), corneal edema (4/11), exuberant corneal granulation tissue (2/11), focal retinal edema (1/11), dyscoria (1/11), and partial suture dehiscence (1/11). Late complications included corneal fibrosis and/or pigmentation (11/11), faint anterior cortical cataracts (3/11), and lipid keratopathy (1/11). Vision was retained in all cases. CONCLUSIONS: This technique offers a surgically challenging but effective treatment for extensive epibulbar melanocytomas. In this case series, complications were mild and transient, with preservation of ocular anatomy and function.

Expression of matrix metalloproteinases, type IV collagen, and interleukin-10 in rabbits treated with morphine after lamellar keratectomy.

PURPOSE: To study the effects of topical administration of 1% morphine on corneal analgesia in rabbits submitted to lamellar keratectomy and to assess the expression of matrix metalloproteinase-1, metalloproteinase-2, metalloproteinase-9 (MMPs), type IV collagen, and interleukin-10 (IL-10) during the treatment. METHODS: Morphine group (MG) received 50 µL of topical 1% morphine four times daily, while the control group received saline instead. Corneal touch threshold (CTT) and the wound area were assessed until corneal healing. Corneal samples were processed for routine histology, immunohistochemistry, zymography, and ELISA. RESULTS: Following keratectomy, CTT increased significantly from 6 to 96 h time points. Mean corneal re-epithelization rate and scores of leukocyte infiltration did not differ significantly between treatment groups. Immunolabeling pattern for MMP-1, MMP-9, and type IV collagen was similar in both treatment groups. In the MG, zymography indicated significantly higher levels of active MMP-2 on days 6 and 12; and in the latent MMP-9, on days 3 and 6, and in the active MMP-9, on day 6. Latent MMP-2 and MMP-9, and active MMP-9 decreased to values close to those of healthy corneas on day 12, but levels of active MMP-2 remained significantly elevated in the MG. IL-10 levels measured on days 1-6 were reduced as compared to those of healthy corneal tissue and returned to levels close to those of healthy corneas on day 12. CONCLUSION: Topical morphine promoted corneal analgesia for up to 4 days and did not delay corneal re-epithelization. The re-establishment of MMPs and IL-10 to levels close to baseline values at the end of the study and the expression of type IV collagen in both groups reinforce that, with caution, 1% morphine can be used after lamellar keratectomy in rabbits.

Visual outcome after corneal transplantation for corneal perforation and iris prolapse in 37 horses: 1998-2010.

REASONS FOR PERFORMING STUDY: We wanted to investigate the visual outcome of horses presented with iris prolapse and treated with corneal transplantation. OBJECTIVE: To evaluate the visual outcome of horses with iris prolapse treated with penetrating keratoplasty alone and penetrating keratoplasty in combination with overlying conjunctival or amniotic membrane grafting. METHODS: A retrospective medical records study of horses presented to the University of Florida Veterinary Medical Center for iris prolapse and treated with penetrating keratoplasty in the period of 1998-2010. Data collected from the medical records included signalment, clinical descriptions of ocular lesions, treatments, and therapeutic outcome. RESULTS: Iris prolapses in this study were caused by corneal ulcers with keratomalacia (n = 37). All horses were treated medically for infection, hyperproteinase activity and iridocyclitis, and then surgically treated with either penetrating keratoplasty alone (n = 9) or penetrating keratoplasty with either a conjunctival pedicle flap (n = 22), amniotic membrane transplant (n = 5) or amnion membrane and conjunctival pedicle flap (n = 1). The eyes were visual postoperatively in a majority of the cases (n = 24; 64.9%). Limited vision was noted in 6 eyes (16.2%), 3 eyes became phthisical (8.1%) and 4 globes were enucleated (10.8%). Graft rejection manifested as some degree of donor corneal graft opacification in all cases. Anterior synechiae were present in 48.6% of the eyes. Wound dehiscence and aqueous humour leakage were also common as post operative problems. CONCLUSION: Penetrating keratoplasty alone or in combination with an overlying graft of conjunctiva or amniotic membrane can achieve a successful visual outcome in a high percentage of horses with iris prolapse.

Comparison of the pig and feline models for full thickness corneal transplantation.

PURPOSE: The goal of this study was to report on the advantages and limitations of the pig and feline models for experimental in vivo corneal transplantation. METHODS: Ten healthy domestic pigs and ten healthy cats were used. Full thickness penetrating keratoplasty was performed using autologous (eight cases), allogeneic (seven cases) or human xenogeneic (three cases) tissue. In two other cases, the inflammatory response to partial thickness trephination (without transplantation) was evaluated. Eyes were assessed daily before and after surgery by slit-lamp, pachymetry, and tonometry. A transparency score ranging from 0 (opaque graft) to 4 (clear graft) was used, based on the slit-lamp examination. Optical coherence tomography, histology, and electron microscopy were performed postmortem. RESULTS: In the pig, the mean (±SD) transparency score for the eight full thickness grafts was 0.88 ± 0.99, ranging from 0 to 3. In the feline model, the mean transparency score for the seven uncomplicated grafts was 3.93 ± 0.19, ranging from 3.5 to 4. Both negative controls without endothelium remained opaque at all time. Intraoperative tendency for iris incarceration into the wound, rapid corneal swelling, suture cheese wiring, and postoperative intraocular inflammation were the main factors jeopardizing the functional success of the corneal transplant in the pig model. CONCLUSION: Suboptimal functional results were obtained after full thickness corneal transplantation in the pig model, while in the feline model, the same protocol yielded uneventful surgeries and clear transplants, with functional results similar to those achieved in human subjects.