Feline corneal sequestra: a review of 64 cases (80 eyes) from 1993 to 2000

Evaluation of photoactivated chromophore for keratitis-corneal cross-linking (PACK-CXL) in feline infectious keratitis-patient demographics, treatment protocols, risk factors, and treatment outcome: a retrospective study

OBJECTIVES

To describe patient demographics and treatment protocols in a population of feline patients undergoing photoactivated chromophore for keratitis-corneal cross-linking (PACK-CXL) as an adjunctive treatment for infectious keratitis. Furthermore, to determine the proportion of PACK-CXL treatment success in the population studied, explore risk factors for treatment failure, and provide recommendations for future PACK-CXL clinical studies.

MATERIALS AND METHODS

Records from four veterinary ophthalmology practices were reviewed to identify eligible patients and extract data. Recorded variables included patient-related factors, ocular examination findings, PACK-CXL protocol parameters, and treatment outcome.

RESULTS

Records for 153 cats (154 eyes) were included. Median age in the treatment success group was 8 years (interquartile range (IQR) 4-12), with a median ulcer depth of 30% (IQR 30-40). Median age in the treatment failure group was 10.5 years (IQR 4.75-12) with a median ulcer depth of 45.9% (IQR 30-75). Persian cats were the most represented brachycephalic breed (52 out of 64 cats). Modified PACK-CXL protocols were used, including fast energy delivery (134 eyes), and increased fluence (52 eyes). The overall proportion of success was 88% (95% CI 84-93), which was variable between clinics. Eighty-two of 89 mesocephalic cat eyes (92%), and 54 of 65 brachycephalic cat eyes (83%) were classified as treatment successes.

CONCLUSIONS

PACK-CXL appeared to be a useful, adjunctive therapeutic modality for the treatment of infectious keratitis in the feline patient population presented here. Brachycephalic cats, older cats, and those with deeper ulcers may be at increased risk for treatment failure.

Application of multi-layer porcine small intestinal submucosa for the reconstruction of deep corneal defects in cats

OBJECTIVE

This study documented the application of porcine small intestinal submucosa (SIS) as a stand-alone scaffold for treating deep corneal defects in cats.

METHODS

Medical records of 20 cats with deep stromal ulcers, perforations, or corneal sequestra that underwent surgical treatment with SIS grafts between 2021 and 2022 were retrospectively reviewed. Data on re-epithelialization time, corneal transparency score, and complications were collected to analyze the reconstruction of deep corneal defects after SIS biomaterial implantation.

RESULTS

All cats were unilaterally affected. The corneal defects varied in size, with a median diameter of 8.3 mm (range: 3-15 mm). Re-epithelialization of the SIS graft was completed 16-32 days after surgery (median, 22.3 days). No, mild, or moderate corneal transparency was detected in 90% of the cases. Complications were observed in eight cases (40%), including aqueous leakage (10%), partial SIS malacia (25%), and persistent bullous keratopathy (5%). The follow-up period ranged 90-725 days, with a median duration of 255 days. The SIS graft was successfully applied as a single scaffold in 17 of 20 cases (85%).

CONCLUSION

The results of this study suggest that the application of commercial SIS is an effective surgical technique for managing deep corneal defects in cats.

Long-term treatment outcomes and risk factors for recurrence in feline corneal sequestrum: 72 cases (2009-2017)

BACKGROUND

This study aimed to evaluate long-term treatment outcomes in feline corneal sequestrum (FCS), compare the recurrence rates between different surgical techniques, identify possible recurrence risk factors and monitor the development of FCS in the contralateral eye.

METHODS

The medical records of 72 cats (79 eyes) with FCS treated between 2009 and 2017 were retrospectively analysed.

RESULTS

The most commonly affected breeds were Persian, domestic shorthaired and Burmesecats. The mean age was 6.9 years. Sixty-five cats (90%) were affected unilaterally. Sixty-six eyes (83%) underwent surgery: keratectomy in 34 eyes (52%) and keratectomy followed by a graft procedure in 32 eyes (48%). Recurrence occurred in 13 out of 66 eyes (19%) at a median of 245 days after surgery. Skull conformation, location of the FCS, type of surgical procedure and concurrent ocular surgery did not significantly affect the recurrence rate. Eighteen cats (27%) developed FCS in the contralateral eye at a median of 635 days after surgery.

LIMITATIONS

Limitations are related to the retrospective nature of the study, the use of telephone follow-up for assessment of recurrence in some cats and the small number of cases.

CONCLUSIONS

Surgical excision had a successful outcome in most cases. The type of surgical procedure and skull conformation did not affect the recurrence rate. One-quarter of the cats developed FCS in the contralateral eye.

Prevalence of feline ophthalmic disorders in South Korea: a retrospective study (2009-2021)

OBJECTIVES

This study aimed to determine the prevalence and clinical presentation of ocular diseases in cats in South Korea.

METHODS

Medical records of cats that were presented for ophthalmology services at Seoul National University Veterinary Medical Teaching Hospital between 2009 and 2021 were reviewed. Collected data included patient signalment, clinical signs, diagnosed ophthalmic disorders and affected eyes. Odds ratios were calculated when a variable was over-represented.

RESULTS

This study recorded a total of 358 eyes (180 cats). Domestic shorthair (DSH) was the most common breed (42.2%), followed by Persian (13.9%) and Scottish Fold (8.3%); 14 (35.6%) other breeds were recorded. The median age at the first presentation was 3 years (range 2 months to 17 years); the highest percentage of cats presented at <1 year (21.7%). The most affected ocular structure was the cornea (28.5%), followed by the lens (19.9%) and uvea (15.3%). The most frequently reported disorders were corneal ulceration (13.2%), uveitis (11.9%), incipient cataract (11.0%), keratitis (5.4%), secondary glaucoma (5.2%) and sequestrum (4.2%). The Exotic Shorthair breed was significantly over-represented with regard to entropion and periorbital fat prolapse (P <0.01). The DSH breed was significantly over-represented with regard to eyelid agenesis (P <0.01).

CONCLUSIONS AND RELEVANCE

This study provides prevalence information for feline ophthalmic diseases and could contribute important data for diagnosing, treating and preventing feline ophthalmic diseases in South Korea.

Epidemiology and clinical presentation of feline presumed hereditary or breed-related ocular diseases in France: retrospective study of 129 cats

OBJECTIVES

This study aimed to describe the epidemiology and clinical presentation of presumed hereditary or presumed breed-related ocular diseases in a population of cats in France.

METHODS

Medical records from between September 2013 and August 2017 were reviewed to identify cats with at least one presumed hereditary or breed-related ocular disease. Cats with concurrent, or a history of, ocular or systemic infectious diseases were excluded. Signalment, history and clinical findings were recorded.

RESULTS

Of the 1161 cats that presented to our institution during the study period, 129 were diagnosed with at least one presumed hereditary or presumed breed-related ocular disease (11.1%, 95% confidence interval [CI] 9.3-12.9). Five ocular abnormalities had a prevalence of >1%: entropion, corneal sequestration, persistent pupillary membrane, cataract and retinal dysplasia. The prevalence of entropion was 2.2% (95% CI 1.3-3.0), with Persians (P = 0.03), Maine Coons (P <0.01) and male cats (P <0.01) being over-represented. The prevalence of corneal sequestration was 2.4% (95% CI 1.5-3.3), with Persians (P <0.01) and Exotic Shorthairs (P = 0.02) being over-represented. Persistent pupillary membranes and cataracts had the same prevalence of 2.3% (95% CI 1.5-3.2), with no particular sex or breed significantly over-represented. Retinal dysplasia had a prevalence of 1.6% (95% CI 0.8-2.3) and Persian cats were over-represented (P = 0.04). Anterior segment dysgenesis had a low prevalence (0.9%, 95% CI 0.4-1.5), with all affected cats being domestic shorthairs and this breed therefore was over-represented (P = 0.04).

CONCLUSIONS AND RELEVANCE

In a French population of cats, presumed hereditary or breed-related ocular diseases accounted for 11.1% of all ocular diseases. Cataracts, corneal sequestration, persistent pupillary membrane, entropion and retinal dysplasia were the most common conditions. Statistical breed over-representation was observed for entropion, corneal sequestration and retinal dysplasia. We recommend that more systematic screening of feline species is conducted.

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.

Genetic Aspects of Corneal Sequestra in a Population of Persian, Himalayan and Exotic Cats

Simple Summary

Corneal sequestrum is a common eye disease in Persian, Himalayan and exotic cats. It is a brown stain on the cornea that can be painful and often requires surgery for full recovery. The cause of this disease is unknown. One hypothesis is that genetic factors influence the disease, but there are no data to support this in the scientific literature. In this study, the influence of genetics on this disease was investigated on the basis of clinical and pedigree data from a cattery. Kittens of some dams in this cattery turned out to have a higher risk of corneal sequestra than kittens of other dams, indicating that genetics indeed play a role. The disease also has a high heritability, which implies that by selecting the right breeding animals, breeders can reduce the risk of corneal sequestra in the offspring. DNA analysis of some of the cats from the cattery could not link the disease to a specific region in the DNA, so it is possible that many different genes in different DNA regions are involved in the development of corneal sequestra.

Abstract

Corneal sequestra are ophthalmic lesions that are remarkably common in Persian, Himalayan and exotic cats. In this study, the genetic aspects of this disease were investigated in a population of cats originating from a single cattery. Odds ratios were calculated for parents with affected offspring. The heritability of (owner-reported) corneal sequestra was estimated with a Markov chain Monte Carlo procedure. Well-phenotyped cases and controls were used for a genome-wide association study. Data from 692 cats originating from the cattery, of which 61 were affected, were used. Cats from two specific mothers had significantly higher odds of developing corneal sequestra, but no significant effect of the fathers was found (after correction for the mothers). The heritability of corneal sequestra was estimated to be 0.96. A genome-wide association study with 14 cases and 10 controls did not reveal an associated chromosomal region. The large effect that genetic factors had on the development of corneal sequestra in this study suggests that selective breeding could be an effective way to reduce the prevalence of this condition in these cat breeds.

Prevalence and characteristics of ocular diseases in Sphynx cats: A retrospective assessment (2012-2021) and comparison with non-Sphynx cats

PURPOSE

To describe the prevalence of ocular diseases in Sphynx cats, and compare disease characteristics with other feline breeds.

METHODS

Medical records of Sphynx cats presented to an ophthalmology referral center between 1/2012 and 4/2021 were examined. Cats of other breeds examined during the same period served as controls.

RESULTS

One hundred ten Sphynx cats were examined during the study period, diagnosed with corneal sequestrum (n = 42 cats), lower eyelid entropion (n = 25), presumed herpetic keratoconjunctivitis (n = 19), conjunctivitis (n = 7), corneal ulcers (n = 6), nasolacrimal duct atresia/obstruction (n = 6), corneal dystrophy (n = 3), eosinophilic keratitis (n = 2), uveitis (n = 2), non-ulcerative keratitis (n = 1), and cataract (n = 1). Corneal sequestrum was significantly more common in Sphynx versus non-Sphynx cats (odds ratio = 8.0, 95% CI = 5.3-12.2, p < .001), and age of diagnosis was significantly younger in Sphynx cats (2.0 ± 1.5 years vs. 5.9 ± 4.0 years, p < .001). Corneal sequestrum recurrence was noted in 19.4% Sphynx eyes and 6.4% non-Sphynx eyes undergoing surgery (p = .015). Lower eyelid entropion-most often bilateral (80%)-was significantly more common in Sphynx versus non-Sphynx cats (odds ratio = 4.1, 95% CI = 2.3-7.1, p < .001), and age of diagnosis was significantly younger in Sphynx cats (0.9 ± 1.4 years vs. 3.5 ± 3.3 years, p < .005).

CONCLUSIONS

Corneal sequestrum and entropion were overrepresented and diagnosed at an earlier age in Sphynx cats when compared with the general feline population. Given the high prevalence, early age of onset, and relatively high recurrence of corneal sequestrum in Sphynx cats, further studies are warranted to better understand etiopathogenesis and preferred therapies.

Corneal Surgery in the Cat: Diseases, considerations and techniques

PRACTICAL RELEVANCE

The ability to recognize, diagnose and treat corneal disease is essential for maintaining vision and comfort in feline patients. Being able to correctly identify appropriate techniques for surgical cases is of particular importance for success when performing corneal surgery.

CLINICAL CHALLENGES

Many different corneal diseases present with similar clinical signs, and it can be hard to determine the appropriate treatment for individual patients. It is essential for the clinician to understand the indications for corneal surgery, instrumentation needed and microsurgical principles prior to attempting these procedures. The prognosis following surgery and potential complications should be discussed with the client.

AUDIENCE

This review article aims to assist in decision-making and to provide detailed guidance for primary care clinicians considering referral of cats for corneal surgery. The review outlines common feline corneal diseases and associated surgical therapies performed by veterinary ophthalmologists, highlighting appropriate instrumentation and case selection. Some surgeries are explained in depth for ophthalmologists and residents in training.

EQUIPMENT

Although some procedures may be performed with common surgical equipment and supplies, most require specialized ophthalmic instrumentation and expertise, which entails significant microsurgical training and practice, as well as financial investment. Most of the procedures require an operating microscope for the best surgical outcomes; however, surgical loupes may be sufficient in some cases. Evidence base: This review article compiles information from many published references on feline corneal diseases and surgeries, complemented by the experience of the authors.

Lamellar Keratoplasty Using Acellular Bioengineering Cornea (BioCorneaVetTM) for the Treatment of Feline Corneal Sequestrum: A Retrospective Study of 62 Eyes (2018–2021)

Simple Summary

Corneal sequestrum is a specific and common corneal disease in cats. Surgery treatment is the recommended option. Acellular bioengineering cornea (ABC) is a popular and effective corneal transplantation material. However, no study has been published to evaluate the effectiveness and outcome of ABC lamellar transplantation for the treatment of feline corneal sequestrum (FCS). The purpose of this retrospective study was to evaluate the surgical effect of ABC lamellar transplantation in the treatment of FCS. All cats were diagnosed with FCS. All eyes received ABC lamellar transplantation for the first time, including 61 cats (62 eyes), aged 6–120 months. The average sequestrum size was 7.98 mm, with a medium of 7.75 mm (range, 4.75–11.75 mm), and the sequestrum thickness included 200 microns for 1 eye (1.61%), 300 microns for 28 eyes (45.16%), 400 microns for 29 eyes (46.77%), and 450 microns for 4 eyes (6.45%). All eyes retained vision after surgical treatment, and there was no recurrence during the follow-up period. This study has several limitations, including incomplete unification and standardization of data collection, some vacancies of follow-up time, inconsistency between then optical coherence tomography(OCT) examination and postoperative photo collection. Despite several limitations, our results show that ABC is easy to obtain and store, and has the choice of different sizes and thicknesses to achieve rapid corneal healing, and satisfactory visual and cosmetic effects in FCS treatment. Acellular bioengineering cornea can be a good alternative for the treatment of FCS.

Abstract

To retrospectively evaluate the effectiveness and outcome of lamellar keratoplasty using acellular bioengineering cornea (BioCorneaVet^TM) for the treatment of feline corneal sequestrum (FCS). The medical records of cats diagnosed with FCS that underwent lamellar keratoplasty with BioCorneaVet^TM between 2018 and 2021 with a minimum of 3 months of follow-up were reviewed. Follow-up examinations were performed weekly for 3 months, and then optical coherence tomography (OCT) examination was performed on select patients at 0, 3, 6, and 12 months post-operatively. A total of 61 cats (30 left eyes and 32 right eyes) were included. The Persian breed was overrepresented, 48/61 (78.69%). Four different thicknesses of acellular bioengineering cornea were used (200, 300, 400, or 450 microns), and the mean graft size was 8.23 mm (range, 5.00–12.00 mm). Minor complications were composed of partial dehiscence, and protrusion of the graft occurred in 7/62 eyes (11.29%). The median postoperative follow-up was 12.00 months (range, 3–41 months). A good visual outcome was achieved in 60/62 eyes (96.77%), and a mild to moderate corneal opacification occurred in 2/62 (3.23%). No recurrence of corneal sequestrum was observed. From the results, lamellar keratoplasty using acellular bioengineering cornea (BioCorneaVet^TM) is an effective treatment for FCS, providing a good tectonic support and natural collagen framework, and resulting in satisfactory visual and cosmetic effects.

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.

Correlation of brachycephaly grade with level of exophthalmos, reduced airway passages and degree of dental malalignment' in Persian cats

For many years, there has been a trend to breed cats with an increasing degree of brachycephalic head features, which are known to have a severe impact on the animals' health and welfare. The direct relation between different grades of brachycephaly and their negative implications have not been researched in this species. The aim of this study was therefore to establish correlations between the different grades of brachycephaly and reduced upper respiratory airways, exophthalmos of the eye globes and malalignment of the teeth in Persian cats. Sixty-nine Persian cats of various skull dimensions and ten Domestic shorthair cats were recruited for the study. The cats' skulls were examined using three-dimensional reconstructions created from Computed Tomography datasets. Brachycephaly was graded using established craniometric measurements (facial index, cranial index, skull index, craniofacial angle). The flow area of the nasal passageways at different locations, the amount of the eye globe not supported by the bony orbit and the axial deviation of the teeth were quantified and evaluated for a correlation with the grade of brachycephaly. The results of this study clearly show that increased grades of brachycephaly in Persian cats resulted in larger extra-orbital parts of the ocular bulbs. The brachycephalic skull dimension also resulted in a lower height of the naso-osseal aperture, while other areas of the nasal airways were not correlated with the severity of brachycephaly. Persian cats showed a significantly increased occurrence of premolar tooth displacement in the upper jaw with increasing brachycephaly grades. It was interesting to note that the measured values had a broad range and values of some individual Persian cats showed an overlap with those of Domestic shorthair cats.

Detection of free-living amoebae in domestic cats with and without naturally-acquired keratitis

Pathogenic free-living amoebae, most notably Acanthamoeba spp., are important pathogens of the human cornea. The importance of infection with free-living amoebae in cats with keratitis is currently unclear. The aim of this study was to determine the frequency of amoeba detection in corneas of cats with naturally-acquired keratitis and in the ocular surface microflora of cats without ocular disease. Clinical ophthalmic and in vivo corneal confocal microscopic examinations were performed on 60 cats with keratitis. Corneal scrapings were analyzed by amoeba culture; cytological evaluation; and Acanthamoeba, Hartmannella, and Vahlkampfia PCR assays. Following ophthalmic examination, conjunctival specimens collected from 60 cats without clinically apparent ocular disease were analyzed similarly. In one cat with ulcerative keratitis, amoeba cysts and trophozoites were detected by in vivo corneal confocal microscopy; an Acanthamoeba sp. was isolated from corneal specimens and detected by Acanthamoeba PCR assay; and suppurative corneal inflammation was present cytologically. An Acanthamoeba sp. was isolated from conjunctival specimens from one cat without clinically apparent ocular disease, but with suppurative inflammation demonstrated cytologically. Both Acanthamoeba isolates belonged to the T4 genotype. Naegleria-like amoebae were isolated in samples from two cats with keratitis and seven cats without clinical ocular disease, but amoebae were not detected by the other assays in these samples. Amoeba detection by culture was significantly (P = 0.01) associated with cytologically diagnosed corneoconjunctival inflammation. This study identified naturally-acquired Acanthamoeba keratitis in cats. Detection of Naegleria-like amoebae in samples from cats with and without keratitis is of uncertain pathological significance.

Keratometry in normal cats: a cross-sectional study in Japan using an automated handheld keratometer

Keratometry was performed in 73 domestic cats of varied signalment in Japan using an automated handheld keratometer. The mean corneal curvature radius was significantly lower for cats younger than 1 year than for those older than 2 years (8.04 mm vs. 8.80-8.99 mm, P<0.01). The radius was significantly greater in males than in females among the cats older than 11 years (9.22 mm vs. 8.84 mm, P=0.01), while the age distributions of the males and females were similar. Corneal astigmatism did not significantly differ across the gender and age groups. The predictability of the corneal curvature and astigmatism was approximately 41-43% and less than 3%, respectively, as a function of age and bodyweight. The results highlighted some age- and sex-related keratometric variations in domestic cats in Japan.

Surgical treatment of canine and feline descemetoceles, deep and perforated corneal ulcers with autologous buccal mucous membrane grafts

Objectives

To report the surgical technique and postoperative outcome of corneal repair with autologous buccal mucous membrane grafts in dogs and cats with descemetoceles, deep corneal ulcers, and perforated corneal ulcers with or without iris prolapse.

Animal studied

Twelve cats (13 eyes) and fourteen dogs (14 eyes) were treated.

Procedures

Grafts were harvested from the unpigmented superior labial mucosa using a biopsy punch. The corneal lesion was carefully debrided and cleaned. The graft was secured to the healthy cornea with a combination of simple interrupted and continuous 9–0 polyglycolic acid sutures. In 25/27 treated eyes, an overlying pedicle conjunctival graft was also performed. A temporary nictitating membrane flap was used in all cases. The pedicle conjunctival graft was trimmed about 10–20 days postoperatively. The median follow‐up period was 549.2 days (range 14–2691 days).

Results

No surgical intra‐operative complications were observed. The ulcers healed and the integrity of the globe was restored in 24/27 treated eyes. Different grades of corneal fibrosis and/or vascularization and/or pigmentation were observed in all cases at the long‐term follow‐up. In two cases, enucleation was performed due to postoperative complications and one animal developed phthisis bulbi. A total of 22/27 treated eyes appeared to have regained effective visual function at the last clinical evaluation.

Conclusions

Autologous buccal mucous membrane grafts appear to successfully manage severe corneal ulcers in dogs and cats, providing a useful and economical alternative to other corneal grafts.

Comparison of computed tomographic ocular biometry in brachycephalic and non-brachycephalic cats

Background and Aim:

Ocular biometry has been used to evaluate ocular parameters; however, several factors need to be considered. In humans, age and sex have been shown to affect ocular biometry. The main factor that affects feline ocular biometry is the head circumference. At present, several reports have revealed that canine ocular biometry differs among dog breeds. However, there are no reports on normal ocular biometry in cats using computed tomography (CT). Therefore, this study aimed to explore feline ocular parameters between brachycephalic (B) and non-brachycephalic (NB) cats using CT and to evaluate the influence of age or sex of cats on ocular biometry.

Materials and Methods:

Twenty-four normal cats were divided into two groups: B (n=12) and NB (n=12). Each group had an equal number of designated males and females. CT was performed under mechanical restraint without general anesthesia and intravenous contrast enhancement. Ocular biometry, dimensions of the internal structure, including attenuation numbers and extra-ocular structures, were evaluated and compared.

Results:

B-cats had a significantly wider globe width (GW) than NB-cats (p<0.05). In addition, globe length (GL) and GW were significantly correlated with the age of the cats. Significant correlation between GL and age was observed in all cats (r=0.4867; p<0.05), NB-cats (r=0.8692; p<0.05), and B-cats (r=0.4367; p<0.05), whereas the correlation between GW and age was observed in B-cats only (r=0.7251; p<0.05). For extra-ocular structures, NB-cats had significantly greater orbital depth than B-cats (p<0.05), and orbital diameter was significantly correlated with age in all cats and B-cats (p<0.05).

Conclusion:

CT can be used for ocular biometric evaluation in cats with different skull types. GW was wider in B-cats, whereas the orbital depth was greater in NB-cats. Moreover, GW, GL, and orbital diameter were affected by the age of the cats. This information will be useful for further ocular diagnosis and treatment, especially in prosthetic surgical procedures.

Facial conformation characteristics in Persian and Exotic Shorthair cats

OBJECTIVES

The primary objectives of the study were to examine the diversity in facial conformation characteristics within a group of Persian (PER) and Exotic Shorthair (EXO) show cats, and to contrast the results to findings within a group of non-purebred domestic shorthair (DSH) and domestic longhair (DLH) cats. The secondary objectives were to determine the PER/EXO show cat owners' perceptions of the breathing status of their cats, and to evaluate if remarks from the cat show judges concerning the cats' head and facial conformation were exclusively related to the aesthetic features of the cats.

METHODS

Sixty-four PER and 12 EXO show cats were prospectively examined at five international cat shows, and 20 DSH/DLH cats were examined at an animal hospital. Facial conformation characteristics were evaluated by examining photos of the cats. Owners of the PER/EXO show cats answered a questionnaire concerning their cats' health status, and they were encouraged to send in the judges' score sheets from the cat shows.

RESULTS

The PER/EXO show cats had higher diversity in facial conformation characteristics than the DSH/DLH cats, and high incidences of hypoplasia of the nose leather (95%), the nose leather top positioned above the level of the lower eyelid (93%), moderate-to-severe stenotic nares (86%), epiphora (83%) and entropion (32%). Owners of 6/76 PER/EXO show cats stated that their cat had increased respiratory sounds and/or trouble breathing at least once a week. The cat show judges' written comments were exclusively related to aesthetic features of the cats' head and facial conformation details.

CONCLUSIONS AND RELEVANCE

Hypoplasia of the nose leather, high position of the nose leather top, stenotic nares, epiphora and entropion were common findings in the PER/EXO show cats but not in the DSH/DLH cats. Few of the cat owners perceived that their cat had problems related to the airways.

Corneal sequestra in cats: 175 eyes from 172 cases (2000-2016)

OBJECTIVES

To report the clinical outcomes of different surgical treatments used to manage feline corneal sequestra in a large number of cases.

MATERIALS AND METHODS

Medical records of 172 cats affected by feline corneal sequestra and surgically managed by different techniques were retrospectively evaluated. Signalment, surgical technique, visual outcomes, postoperative corneal clarity and recurrence were evaluated.

RESULTS

One hundred and seventy-two cats (175 eyes) of different breeds, ages and sex were included in the retrospective case series. The Persian was the most represented breed (123/172; 71.5%), followed by Exotic Shorthair breed (21/172; 12.2%), Domestic shorthair breed (21/172; 12.2%) and a smaller group of other different breeds (7/172). Surgical management included a superficial (84/175 eyes) or deep (91/175 eyes) lamellar keratectomy in association with the following covering techniques (tectonic support and/or protective support): nictitans membrane flap (n=84), conjunctival pedicle graft (n=52), BioSISt graft (n=9), corneoconjunctival transposition (n=7), corneoconjunctival transposition+nictitans membrane flap (n=6), conjunctival free island graft (n=6), BioSISt+conjunctival pedicle graft (n=6), BioSISt+nictitans membrane flap (n=4) and bridge conjunctival graft (n=1). At the end of the retrospective case series, visus was present in all patients and no or mild corneal opacity was detected in 86% (151/175 eyes) of the patients. Sequestra recurred in 20 eyes (20/175; 11.4%) within 2 years.

CLINICAL SIGNIFICANCE

This paper describes the clinical outcomes of a large number of cases of feline corneal sequestra treated with varying surgical techniques and provides useful insight regarding the prognosis and outcomes of these techniques within feline ophthalmology.

Persian cats under first opinion veterinary care in the UK: demography, mortality and disorders

Persian cats are a popular cat breed worldwide, and especially in the US, Europe and Asia. This study aimed to describe the demography, common disorders and mortality in Persians under general practice veterinary care in 2013 in the UK. The study population of 285,547 cats overall included 3235 (1.1%) Persians. Mean adult Persian bodyweight was 3.9 kg (SD 0.9) and median age was 7.0 years (IQR 3.3–11.6). At least one disorder was recorded in 2099 (64.9%) Persians. The most common specific disorders were haircoat disorders (411, 12.7%), periodontal disease (365, 11.3%), overgrown nails (234, 7.2%), and ocular discharge (188, 5.8%). The most common disorder groups were dermatological (578, 17.9%), ophthalmological (496, 15.3%) and dental (397, 12.3%). Median longevity was 13.5 years (IQR 9.9–16.0). The most common grouped causes of death were renal disease (102, 23.4%), neoplasia (37, 8.5%) and mass-associated disorder (35, 8.0%). This is the first study to use general practice data to examine the overall health of Persian cats. With haircoat, ocular and dental disorders being the predominant disorders identified, this study highlights the need for increased owner awareness to manage and prevent the typical health problems associated with this breed’s phenotype.

Feline bacterial keratitis: Clinical features, bacterial isolates, and in vitro antimicrobial susceptibility patterns

OBJECTIVE

To describe clinical characteristics, bacterial isolates, and in vitro antimicrobial susceptibility patterns for cats with bacterial keratitis.

ANIMALS STUDIED

Eighty one cats with bacterial keratitis.

PROCEDURES

Medical records of cats with a clinical diagnosis of bacterial keratitis, confirmed by corneal culture, were reviewed from June 2004 to July 2017. Animal signalment, bacterial isolates, aerobic bacteria in vitro antimicrobial susceptibility test results, and pertinent clinical features were recorded. Percentages of susceptible aerobic bacterial isolates were statistically compared among selected antimicrobials.

RESULTS

There were 102 aerobic bacterial isolates recovered from corneal samples of the 81 cats presented with bacterial keratitis. The most frequent bacteria isolated were Staphylococcus species, which constituted 55% (56/102) of total isolates. All aerobic bacterial isolates grouped together had the highest percentage of susceptibility to ofloxacin (100%), ciprofloxacin (94%), chloramphenicol (93%), doxycycline (92%), ticarcillin (90%), gentamicin (89%), moxifloxacin (89%), tobramycin (86%), neomycin (85%), amikacin (84%), and cefazolin (84%). The same isolates had the lowest percentage of susceptibility to polymyxin B (2%), bacitracin (15%), and clindamycin (31%). When analyzed separately, the isolated Staphylococcus species had the highest percentage of susceptibility to ofloxacin (100%), tobramycin (93%), and neomycin (85%) and the lowest percentage of susceptibility to polymyxin B (3%) and bacitracin (13%).

CONCLUSIONS

Members of the Staphylococcus genus were the most frequent bacteria isolated from cases of feline bacterial keratitis. On the basis of in vitro susceptibility testing and mechanism of action, ofloxacin, ciprofloxacin, ticarcillin, gentamicin, or moxifloxacin are recommended for initial antimicrobial therapy of suspected bacterial keratitis in cats.

Motivation of Owners to Purchase Pedigree Cats, with Specific Focus on the Acquisition of Brachycephalic Cats

Background: Cats are globally popular pets and pedigree cats are increasingly prevalent, with brachycephalic breeds being the most registered breeds. How owners decide upon and acquire their cats is poorly understood. Moreover, there are growing concerns about the health and welfare of brachycephalic (BC) dogs and recent studies are raising the awareness of health and welfare problems in BC cats. Methods: An online survey investigated owners' motivations, perceptions and behaviours prior to, during and following acquisition of non-pedigree (NP), extreme brachycephalic pedigree (BC; i.e., Persian and Exotic Shorthair) and mild to non-BC pedigree (P) cats. Results: The survey received 1367 valid responses (NP n = 882, P n = 400, BC n = 85 (6.2%)). There were marked differences between NP, P and BC owners' perception of their cats' health and welfare, reason(s) for acquisition and its process. Owners of NP were less influenced by appearance, behaviour and other features than P or BC owners. In contrast, P and BC owners were highly influenced by appearance, with P owners also placing greater importance on good breed health than BC owners. BC owners were less likely to recommend their breeds to prospective cat owners, apparently concerned by high maintenance requirements. Conclusion: Further research is needed to determine how decision-making is constructed and how it may be improved, especially in respect of welfare outcomes for extreme BC cats given the increased weighting given to appearance over health.

Use of cyanoacrylate adhesive in the surgical management of feline corneal sequestrum: 16 cases (2011-2018)

OBJECTIVE

To evaluate the use of cyanoacrylate adhesive as an adjunct to lamellar keratectomy in cats with corneal sequestrum.

METHODS

Medical records were reviewed to identify cats with naturally occurring midstromal corneal sequestra treated with lamellar keratectomy and cyanoacrylate adhesive. All cats also had a bandage contact lens placed for postoperative comfort. Data collected included breed, age, sex, and reproductive status of the cat, eye involved, presence or absence of neovascularization at the time of surgery, history of prior sequestra, additional ocular procedures performed, use of neuromuscular blocking agents, procedure time, time to cessation of topical medications, time to recurrence or last follow-up, and complications aside from recurrence.

RESULTS

Sixteen cats met study criteria, with a median follow-up time of 17.5 months in those without recurrence. Median time to cessation of topical medications was 4 weeks. Fourteen cats (87%) have not experienced recurrence. Other than recurrence in two cats, no significant complications were noted. Aside from purebred status, no commonalities were found between the two cats with recurrence. Neuromuscular blocking agents were not used during surgery in most cases. Median procedure time was 10 minutes.

CONCLUSIONS

Cyanoacrylate adhesive is an effective and safe alternative to grafting procedures in cats undergoing lamellar keratectomy for treatment of corneal sequestrum. Recurrence rates are comparable to those seen with grafting techniques. Benefits of this approach include decreased anesthesia time, lower procedure costs, and short duration of postoperative treatment.

Health and Behavioral Survey of over 8000 Finnish Cats

A comprehensive feline health survey was conducted to reveal breed-specific inheritable diseases in Finnish pedigree cats for genetic research. Prevalence of 19 disease categories and 227 feline diseases were defined in a study population of 8175 cats belonging to 30 breeds. Dental and oral diseases, with a prevalence of 28%, and dental calculus and gingivitis (21 and 8%, respectively) were the most prevalent disease category and diseases among all cats and in most of the breeds. An exception was Korats, which were more often affected by the diseases of the respiratory tract (23%) and asthma (19%). Other prevalent disease categories affected various organ systems, such as the skin (12%), the urinary system (12%), the digestive tract (11%), eyes (10%), the musculoskeletal system (10%), and genitals of female cats (17%). Prevalent health or developmental issues included repetitive vomiting (4%), tail kink (4%), feline odontoclastic resorption lesion (4%), urinary tract infections (4%), as well as cesarean section (6%) and stillborn kittens (6%) among female cats. We found 57 breed-specific conditions by Fisher’s exact tests and logistic regression analyses, including 32 previously described and 19 new breed-specific diseases. The genetic defect has already been found in six of them: polycystic kidney disease, progressive retinal atrophy, hypertrophic cardiomyopathy, and three types of tail malformations. Behavioral profiling revealed breed-specific traits, such as an increased human avoidance in British Short and Longhairs and a higher level of aggression in Turkish vans. Our epidemiological study reveals the overall health profile in Finnish pure and mixed breed cats and identifies many breed-specific conditions without molecular identity for genetic research.

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.

Porphyrins are not present in feline ocular tissues or corneal sequestra

OBJECTIVE

To determine if feline lacrimal glands, glands of the third eyelid, corneas, and corneal sequestra contain porphyrins, which could be responsible for the brown/amber discoloration of corneal sequestra and tears in affected cats.

PROCEDURES

Samples of grossly normal cornea, lacrimal gland, gland of the third eyelid, and sequestra obtained via keratectomy were collected. Porphyrin concentrations of the homogenate were determined by spectrofluorometry with protoporphyrin IX and coproporphyrin III dihydrochloride used as standards. A hamster harderian gland was used as a positive control.

RESULTS

Normal tissues were harvested from one eye each of 14 nonclient owned, adult, mixed-breed, short-hair cats euthanized for reasons not associated with this study. Eighteen sequestra were acquired from cats undergoing unilateral lamellar keratectomies. Breeds of the affected cats included eight Himalayan, five domestic shorthair, and one each of four other breeds. Only the positive control and standards contained levels of porphyrins above background. All feline samples examined were histologically normal with no evidence of porphyrins.

CONCLUSIONS

Porphyrins are absent in normal feline lacrimal glands, corneas, and corneal sequestra. Porphyrins do not appear to be the cause of the brown/amber color of feline corneal sequestra.

Treatment of corneal ulcers: when is surgery indicated?

PRACTICAL RELEVANCE

While corneal ulcers in cats frequently arise secondarily to feline herpesvirus (FHV-1) infection, and thus medical therapy is often indicated, other causes include trauma, eyelid abnormalities (agenesis, entropion, dermoids and neoplasia), tear film abnormalities and neurological deficiencies (trigeminal nerve paralysis or facial nerve paralysis). In some such cases, surgery is required. Treatment always needs to be tailored carefully according to the depth and progression of the ulcer, any concurrent ophthalmic disease, the patient's general health and demeanour, and owner compliance and financial circumstances.

PATIENT GROUP

All age groups and breeds can suffer with ulcerative keratitis although some breeds are over-represented for some types of corneal ulceration.

EVIDENCE BASE

The scientific literature on feline ulcerative keratitis is extensive. This article reviews the surgical indications for corneal ulceration in cats with reference to the current evidence base.

Aetiology of corneal ulcers assume FHV-1 unless proven otherwise

OVERVIEW

Feline ulcerative keratitis is a common presenting complaint and is frequently a sequela of feline herpesvirus 1 (FHV-1) infection; so much so, in fact, that it is fair to assume an FHV-1 aetiology until proven otherwise. Other potential causes of ulceration are trauma or underlying eyelid abnormalities (entropion, ectropion, agenesis, dermoids, neoplasia), lash abnormalities (ectopic cilia, trichiasis), tear film abnormalities or neurological deficiencies (trigeminal nerve paralysis, facial nerve paralysis).

CLINICAL CHALLENGES

The management of corneal ulceration in cats is frequently challenging, and treatment needs to be tailored carefully to the individual cat, its temperament, and the disease process present.

EVIDENCE BASE

The scientific literature on feline ulcerative keratitis is extensive, particularly that related to FHV-1 infection. The aim of this article is to review the aetiology and diagnosis of corneal ulceration in cats with particular reference to the evidence base available.

PATIENT GROUP

All age groups and breeds can suffer with ulcerative keratitis. Breed predispositions are present for some forms of corneal ulceration, and these are discussed.

Treatment of feline herpesvirus-1 associated disease in cats with famciclovir and related drugs

BACKGROUND

Feline herpesvirus 1 (FHV-1) is a common cause of ocular and upper respiratory disease in cats and kittens, and a potential cause of eosinophilic dermatitis.

HYPOTHESIS

The systemic anti-herpes drug, famciclovir (Famvir; Novartis), would be effective in the clinical management of disease attributable to FHV-1, including conjunctivitis, keratitis, corneal sequestra, rhinosinusitis and FHV-1 associated dermatitis.

CLINICAL OUTCOME

Oral famciclovir was used to treat signs considered referable to FHV-1 in 10 cats: four had primary ocular disease, two had rhinosinusitis and four had FHV-1 associated dermatitis. Patients treated in Australia (five cats) and Europe (one cat) were given 62.5 mg of famciclovir once or twice daily. Four cats treated in the USA were given 125 mg three times daily. Famciclovir was uniformly well tolerated and, in all cases, had a positive impact on the patient's condition. The apparent improvement in lesions was superior to what had been achieved previously using other therapeutic strategies. One cat with severe destructive rhinosinusitis was significantly improved by a 4-month course of famciclovir in combination with antibacterials. Corneal sequestra detached in two out of three cats treated; cats with ocular signs were qualitatively more comfortable, with reduced clinical signs and an improved appearance of the eyes. Critically, oral famciclovir therapy was considered more convenient than topical ocular therapy. All four cats with FHV-1 associated dermatitis improved substantially, although relapse occurred subsequently in three patients. A further cat with presumptive FHV-1 associated dermatitis responded to topical aciclovir cream before famciclovir could be sourced.

CONCLUSIONS

Famciclovir appears to be a promising systemic drug for treating diseases associated with FHV-1 infection. More rigorous clinical trials are required to optimise the dosing regimen for safe and effective specific anti-herpes treatment in feline clinical medicine.

Congenital and hereditary ocular abnormalities in cats

Congenital and inherited ocular diseases are reported less frequently in the cat than the dog. The 2 species also differ in their array of disorders, with familiar canine abnormalities like cataracts overshadowed by unique feline diseases such as eyelid agenesis and corneal sequestration. Organized according to the primary ocular structure affected and commingling congenital and inherited disorders in each section, the review begins with multiple ocular anomalies and their impact on globe-orbit relationship. Adnexal disorders include eyelid agenesis, entropion, dermoid, and nictitans gland protrusion. Corneal abnormalities range from the routine sequestrum and PPM-related opacity to those rare infiltrates accompanying inborn errors of metabolism. Brief descriptions of uveal anomalies, primary glaucoma, cataracts, and lens luxations follow. Retinal dysplasia and progressive retinal atrophy complete the summary. Suspicions of heritability are often based on small numbers of animals in sporadic reports of ocular disease, but the Persian, Burmese, and Siamese are among the breeds repeatedly linked with one or more of these disorders.

Feline Corneal Disease

The cornea is naturally transparent. Anything that interferes with the cornea's stromal architecture, contributes to blood vessel migration, increases corneal pigmentation, or predisposes to corneal edema, disrupts the corneas transparency and indicates corneal disease. The color, location, and shape and pattern of a corneal lesion can help in determining the underlying cause for the disease. Corneal disease is typically divided into congenital or acquired disorders. Congenital disorders, such as corneal dermoids are rare in cats, whereas acquired corneal disease associated with nonulcerative or ulcerative keratitis is common. Primary ocular disease, such as tear film instability, adenexal disease (medial canthal entropion, lagophthalmus, eyelid agenesis), and herpes keratitis are associated with the majority of acquired corneal disease in cats. Proliferative/eosinophilic keratitis, acute bullous keratopathy, and Florida keratopathy are common feline nonulcerative disorders. Nonprogressive ulcerative disease in cats, such as chronic corneal epithelial defects and corneal sequestration are more common than progressive corneal ulcerations.

Feline corneal sequestrum: laboratory analysis of ocular samples from 12 cats

Feline corneal sequestrum is a common ocular condition typified by brown to black discoloration of the cornea. The nature of the discoloration has not been identified. The purpose of this study was to perform a laboratory investigation of ocular samples from 12 clinical cases of feline corneal sequestrum in an attempt to characterize the nature of the discoloration. The 12 cases were referred to the Ophthalmology Unit at the Animal Health Trust between April and September 2000, and were also part of a clinical review of 64 cases of feline corneal sequestrum described separately. Five laboratory techniques that are routinely performed at the Biomaterials Unit, Aston University were employed for analysis of the ocular samples. Ocular material included corneal sequestrum, tear samples, meibomian gland secretions, and bandage contact lenses from the 12 clinical cases. High-performance liquid chromatography data showed that total tear lipid in affected eyes was significantly lower than in control eyes (P = 0.016); total tear lipid in affected eyes was lower than in the unaffected, contralateral eyes of the same cat but the difference was not significant (P = 0.29). The presence of an unknown lipid class was observed in tears and meibomian secretions of affected, contralateral and control eyes. Scanning electron microscopy showed that the discoloration in affected corneas was not due to the presence of iron. Fluorescence spectroscopic analysis of sequestra, unaffected corneas and contact lenses (from affected and contralateral/unaffected eyes) showed that lipid and protein were present but did not play an important role in sequestra. Ultraviolet-visible light absorbance spectroscopy revealed a peak at 385 nm in unaffected corneas that was absent in sequestra and the difference was significant (P < 0.0001); this peak may be a characteristic feature of the normal feline cornea. The absorbance spectra displayed a peak at 280 nm in two sequestra suggesting that chromophore groups (e.g. melanin) were present. Optical microscopy performed on 10 sequestra revealed the presence of particles, which were consistent with the appearance of melanin particles, providing laboratory evidence that characterized the nature of the discoloration as melanin for the first time.