Surgical correction of aberrant conjunctival overgrowth in a rabbit: a case report

A dwarf rabbit presented with unilateral aberrant conjunctival growth. Allgoewer’s U-suture therapy was initially used to correct the overgrowth. Centrifugal incisions extending up to the limbus were made on the hypertrophic conjunctiva. Transpalpebral limbal fixation was performed next. When the symptoms recurred 3 weeks later, a second operation was performed using the Lembert suture method instead. The overgrowing membrane was excised radically just posterior to the limbus. The conjunctiva was then sutured using the Lembert pattern. The rabbit recovered with no further complications.     

Comparative morphology of epicorneal conjunctival membranes in rabbits and human pterygium

A rarely described ocular lesion in the rabbit is presented following the observation of four cases. It is a membrane of conjunctival origin that advances progressively, without adhering, towards the center of the cornea. Clinically the lesion in rabbits looks like pterygium in man, but with several differences: in rabbits, the conjunctival fold is absolutely free and does not penetrate into the superficial corneal layers. It originates from all the limbal circumference in a symetric growth. The cornea itself remains unaltered. The fold consists of fibroblasts and collagen. The microscopic findings suggest the lesion is possibly of a collagenous dysplasia.     

A case of conjunctival melanoma in a cat

Since 1985, 5 cases of feline conjunctival melanoma have been reported in the literature. Information on feline conjunctival melanoma epidemiological features, localizations, macroscopic features and histological features is limited. We are describing the clinical, histopathologic features and outcomes in a cat that presented clinically with a slow developing dark brown mass located under the upper eyelid of the left eye. Pertinent literature is reviewed; and the recognizable clinical features and treatment are discussed. The mass was surgically resected. Despite its size, the lesion was easily separated from underlying tissues, making possible a macroscopic complete resection that left intact the adjacent conjunctiva. The tumour histological examination has showed a pigmented melanoma lacking encapsulation, but presenting a clear zone delimiting the lesion. It was exclusively composed of epithelioid cells, and presented mild cellular anaplasia and weak mitotic activity. These features allowed it to be classified as a quite differentiated melanoma with few signs of potential malignancy. In accordance with these histologic features, no recurrence has been registered 34 months after surgery. Thus, a favorable outcome is now reported for two out of six cases of conjunctival melanoma in the cat. This report also confirms the predilection for this neoplasm to arise from the bulbar conjunctiva.     

Extranodal conjunctival Hodgkin's-like lymphoma in a cat

A seven-year-old female spayed Domestic Short-haired cat was brought for examination following a four-month history of conjunctivitis in the right eye. The superior palpebral conjunctiva was diffusely swollen and firm, displacing the right globe ventrally and preventing full closure of the eyelids. The right popliteal lymph node was enlarged as were several other peripheral lymph nodes. An incisional biopsy of the conjunctival swelling revealed a lymphoid neoplasm, the cellular make up of which suggested features of feline Hodgkin's-like lymphoma. Although the neoplasm was poorly responsive to standard chemotherapeutic protocols for lymphoma, radiation therapy rapidly reduced its size. Three years following the initial diagnosis, there has been no recurrence of the conjunctival neoplasm. To the authors' knowledge, there are no previous reports of extranodal or adnexal (conjunctiva, eyelid, orbit) Hodgkin's-like lymphoma in the veterinary literature.     

Seasonal effects on the aerobic bacterial and fungal conjunctival flora of normal thoroughbred brood mares in Florida

Objective To evaluate seasonal effects on the presence or absence of fungal and aerobic bacterial flora of the conjunctival fornix of normal Florida Thoroughbred horses. Sample population Both eyes of 100 horses. Procedure Horses with normal anterior segment ophthalmic examinations from three farms in north central Florida were included. Each animal had the ventral conjunctival fornix of each eye swabbed with sterile culturettes. Samples were taken in October, January, April, and July (1999–2000). Aerobic and fungal cultures were plated. Bacterial cultures were reviewed at 24 and 48 h. Fungal cultures were reviewed weekly for 4 weeks. Logistic regression analysis with season as a factor and age of the horse as a covariate was performed. Statistical significance was set at P < 0.01. Results Horses ranged from 3 to 24 years of age, with a median age of 9 years. Twenty‐four genera of bacteria and 35 genera of fungi were recovered. Corynebacterium sp., Staphylococcus sp., Bacillus sp. and Moraxella sp. were the bacteria most frequently isolated. Mold species, dematiaceous mold species, Chrysosporium sp., Cladosporium sp., and Aspergillus sp. were the most frequently recovered fungi. Season did not have a significant effect on the presence of microorganisms isolated for individual horses adjusted for age. Younger horses had an increased incidence of gram‐negative rods and fungal isolates. The number of bacteria and fungi isolated are not uniform across seasons. Conclusion There were no significant differences between the number or type of organisms cultured during the sampling seasons in normal Florida horses. A large range of normal bacterial and fungal flora were isolated from these horses. The number of bacteria and fungi isolated are not uniform across seasons. The likelihood of detecting an organism depends on the horses’ age.     

360-degree conjunctival grafting for management of diffuse keratomalacia in a dog

We present a report describing use of a 360-degree conjunctival graft for management of progressive keratomalacia refractory to medical treatment in a 5-month-old American Cocker Spaniel. In the dog of this report, the extension of melting to nearly the entire corneal surface limited surgical options. Following surgery and later resection of the graft, the patient is visual with minimal corneal opacity. Numerous corneal grafting techniques have been described in companion animals, but require special materials and may not be possible when melting is extensive. Although older animals or animals with additional corneal pathology may have less ideal outcomes in terms of corneal clarity than the patient of this report, we believe that 360-degree conjunctival grafting offers a viable and cost-effective option for management of cases with extensive keratomalacia that may otherwise have resulted in enucleation.     

Feline conjunctival melanoma: histopathological characteristics and clinical outcomes

Purpose  We report on the histopathology and clinical features of 21 cases of feline conjunctival melanoma.
Methods  A total of 18 cases are from the COPLOW collection and three cases from Antech Diagnostics. We tabulated the location of the tumor, pigmentation, cell shape, mitotic index and presence of multinucleated tumor cells. Surveys were sent to referring ophthalmologists to obtain further information about each case.
Results  The mean age of the cats was 12.4 years. A total of 11 cases were neutered males, six spayed females, and one each of intact female and male. Thirteen of the 21 cases were located on the bulbar conjunctiva, three on third eyelid only, three on palpebral conjunctiva. Sixteen tumors were pigmented while five were amelanotic. Seventeen of the cases consisted of round cell only while four cases were mixed populations of round and spindle cell. Fourteen of the cases contained multinucleated cells. The mitotic index ranged from 0 to 45 mitotic figures/10 HPF. Of the 13 cases with adequate follow-up information, four showed local recurrence while three reported metastasis. Eight cats had died at the time of the survey. Survival time post-diagnosis ranged from 0.5 to 36 months. Two cases had metastasized to the submandibular lymph nodes and in a third case, an abdominal mass was detected.
Conclusions  Feline conjunctival melanoma is most frequently found on the bulbar conjunctiva, are mostly round cells and suggest that conjunctival melanoma in cats has a poorer long term prognosis than the same neoplasm in dogs.     

Congenital stricture of the vestibulo-vaginal fold in a mare with normal karyotype

A diagnosis of congenital stricture of the vestibulo-vaginal fold was reached in an 11-year-old mare without previous reproductive records, during a breeding soundness examination. The mare had an annular stricture of the vestibule–vaginal fold that did not allow palpation or vaginoscopic visual examination of the anterior portion of the vagina. Endoscopic evaluation of both anterior and posterior portions of the vagina revealed a normal mucosa without scar tissue. Ultrasound examination of the cervix, uterus and ovaries did not reveal any other abnormality. The mare had a normal karyotype – 64 XX. Vestibulo-vaginal stricture or stenosis is a congenital anomaly that occurs when there is an incomplete perforation of the hymen or occurs in association with hypoplasia of the genital canal that results in the formation of an annular fibrotic stenosis at the vestibule–vaginal junction. To our knowledge, this is the first report of vestibulo-vaginal stricture in a mare with confirmed normal karyotype, 64,XX.     

Primary conjunctival mast cell tumor in a Labrador Retriever

A 4-year-old, intact male Labrador Retriever with a rapidly progressive conjunctival mass was evaluated. Ocular examination showed a 2-cm elongated mass arising from the superior bulbar conjunctiva of the left eye. The mass resulted in distortion of the palpebral fissure and contacted the superior aspect of the cornea without modifying its structure; no adhesion to the sclera was detected. The superior palpebral conjunctiva was unaffected, and the remaining ocular examination was normal. The initial diagnostic work-up included CBC, serum biochemical analysis, urinalysis, and fine needle biopsy of the mass. A poorly differentiated mast cell tumor was diagnosed by cytology. Immunocytochemistry was performed to evaluate Ki-67 proliferation index, and 54/1000 tumoral nuclei showed a dark red staining. After a complete clinical staging, the mass was excised and identified histologically as a grade-II mast cell tumor. An adjuvant treatment with prednisone and vinblastine was instituted because of the limited excisional margins. No evidence of local recurrence or metastasis has been apparent during the 29-month follow-up period. This report contributes to the current literature pertaining to canine conjunctival mast cell tumors; unfortunately, the paucity of case reports and the absence of large studies regarding this tumor make conclusions regarding its biologic behavior impossible.     

Feline conjunctival hemangioma and hemangiosarcoma: a retrospective evaluation of eight cases (1993-2004)

The purpose of this retrospective study was to evaluate feline primary conjunctival vascular tumors of endothelial origin. Eight cases (six hemangiomas, two hemangiosarcomas) from a collection of 3460 feline submissions between 1993 and 2004 were evaluated using routine hematoxylin and eosin (H&E). Signalment, location, size, duration, epithelial pigmentation, margins, adjuvant therapy, outdoor activity, and geographic location, comparing ultraviolet (UV) radiation levels by state, were recorded. Follow-up information was available for five cases. In this study, the average age was 10.6 years, with neutered males over-represented. The Domestic Short-haired cat was most commonly affected. The most common anatomic site was the nictitating membrane, with the left eye preferentially affected. The average size and duration, prior to presentation, was 7.5 mm and 4.4 months, respectively. Seven of eight cases were devoid of epithelial pigmentation in nonaffected areas and the majority of cases were from states with high annual UV-light exposure. Only cases of hemangiosarcoma underwent surgical re-excisions following incomplete excision; however, no further recurrences were reported. No cases evaluated had evidence of metastatic disease at the time of excision. Surgical excision alone may be curative. However, recurrence is possible. These tumors demonstrate similar predilection sites and involvement of nonpigmented epithelium, as is true in canine cases, which may relate to risk factors as well.     

Canine conjunctival hemangioma and hemangiosarcoma: a retrospective evaluation of 108 cases (1989-2004)

Canine conjunctival tumors of vascular endothelial origin are common, although under-reported. The purpose of this study was to evaluate the epidemiology of and potential risk factors for these tumors. This study evaluated 108 cases (70 hemangiomas, 38 hemangiosarcomas) from 8300 canine submissions between 1989 and 2004. Signalment, location, pigmentation, size, duration, diagnosis, margins, ancillary therapy, and geographic location were recorded. Follow-up information was available for 49 cases. Each case was matched with two unaffected controls and compared using logistic regression analysis. Average age upon presentation was 8.6 years; there was no sex predilection. Risk of conjunctival tumors was statistically different among breed groups (P = 0.0010), demonstrating a propensity to occur in groups likely to have increased outdoor activity. Primary involvement occurred within nonpigmented epithelium along the leading edge of the nictitating membrane (41/108) and temporal bulbar conjunctiva (33/108). The etiology remains unknown; however, the strong site predilection, involvement of nonpigmented epithelium, and development within specific breed classes strongly suggest ultraviolet (UV) light as a significant risk factor. In a full-logistic model including breed, gender, age, and UV exposure, UV was not a statistically significant variable (P = 0.1215). In a reduced-model including UV only, significance was approached (P = 0.0696) and posthoc contrast demonstrated a significant linear trend with increasing UV exposure (P = 0.0147). In separate analysis of risks associated with hemangiosarcoma, compared with hemangioma, breed was not significant while increasing UV exposure was significant (P = 0.0381). Early surgical therapy is recommended and may be curative; however, recurrence is possible and more likely with hemangiosarcomas (11/20).     

Allergic conjunctivitis and conjunctival provocation tests in atopic dogs

Introduction Canine atopic dermatitis (cAD) is a very common disease, but little is known about eye involvement. The conjunctival provocation test (CPT) is used in human to study the ocular response to allergenic stimuli and to evaluate anti‐allergic therapy. To our knowledge it has not been used in dogs. Objectives To evaluate the prevalence of ocular signs in a population of atopic dogs and relate these with clinical cAD scores; and the usefulness of CPT for dust mites in atopic dogs with itchy eyes. Procedures Sixty cAD patients were evaluated for (i) ocular signs of allergic conjunctivitis including conjunctival hyperemia, chemosis, epiphora, ocular discharge, pruritus and corneal involvement, graded 0 to 3 according to severity, and (2) cAD Extent and Severity Index (CADESI‐03). Additionally, CPTs for Dermatophagoides farinae (n = 12) and Dermatophagoides pteronyssinus (n = 12) were performed in sensitized atopic dogs and 24 control dogs. Results Periocular and ocular signs of allergy were present in 60% (36/60) of cases. Conjunctival hyperemia (90%) was the most common sign. Severity of ocular signs was significantly correlated with eye pruritus (r_s = 0.690, P = <0.001) and skin lesions score for head region (r_s = 0.261, P = 0.04). A highly significant difference (P < 0.001, Fisher test) was found in CPTs between the test and the control groups. Conclusion Allergic conjunctivitis signs associated with cAD seem under valuated so these patients would benefit from an ophthalmologic evaluation. Furthermore, we found CPT to be a reliable, easy to perform and safe test for the etiologic diagnosis of allergic conjunctivitis in the dog.     

Seasonal prevalence of fungi in the conjunctival fornix of healthy cows during a 2‐year study

Objective The aims of the present paper were to: (i) identify and quantify conjunctival fungi isolated from healthy cows; (ii) verify the influence of different methods of farm management on the prevalence (percentage of positive cultures for each fungal species per farm) of conjunctival fungi. Material and methods Forty Friesian and twenty Limousin female cows aged 1–10 years stabled in three farms with different managements (farm 1: cows housed strictly indoors; farm 2: cows housed outside during the day and inside the stall during the night; farm 3: cows housed strictly outdoors) were investigated for conjunctival fungal flora. Air and food were also tested. Specimens were collected every season during a 2‐year study. Identification of colonies of filamentous fungi was achieved to the genus level on the basis of macro‐ and microscopic features. Results The total number of eyes positive for fungi ranged from 85 to 100% at farm 1, from 65 to 95% at farm 2, and from 55 to 95% at farm 3. Fungi most frequently isolated from conjunctival fornix were Cladosporium spp. and Penicillium spp. Statistical analysis did not show any differences in fungal prevalences among the three farms during the same season. Some fungal species were consistently isolated while others were intermittently isolated. Conclusions Fungi found in the conjunctival fornix of cows might represent transient seeding from the environment, as suspected in other species. The prevalence of conjunctival fungal organisms is not different in cattle housed indoors vs. outdoors.     

Investigation of bacterial microorganisms in the conjunctival sac of clinically normal dogs and dogs with ulcerative keratitis in Beijing, China

Objective To determine the bacterial microorganisms in the conjunctival sac of clinically normal dogs and dogs with ulcerative keratitis in Beijing, China. The effect of breed, sex and age of dogs and season on the presence or absence of bacteria in the conjunctival sac of clinically normal dogs was evaluated. Sample population This investigation included 240 healthy dogs, 27 dogs with unilateral corneal ulcer and one dog with bilateral corneal ulcer. Procedure The 480 samples from healthy dogs and the 29 samples from dogs with ulcerative keratitis were incubated in an aerobic and 5% CO₂ environment at 37 °C for 48 h. Logistic regression analysis was performed. Statistical significance was set at P < 0.01. Results Of 480 normal eyes, Staphylococcus spp. were the most frequently isolated organisms (40.29%). Neisseria spp. (11.47%) were the next most frequently isolated organisms, followed by Corynebacterium spp. (9.4%). Of 29 eyes with ulcerative keratitis, Staphylococcus spp. were also the most frequently isolated bacteria (47.06%). Streptococcus spp. (12.94%) and Pseudomonas spp. (8.24%) were the second and third, respectively. Season (P = 0.002) was a significant factor influencing presence or absence of bacterial microorganisms in the conjunctival sac of normal dogs in Beijing, China, while the effects of breed (P = 0.095), sex (P = 0.588) and age (P = 0.866) of dogs were insignificant. Conclusion Staphylococcus spp. were the most frequently isolated organisms, and S. intermedius predominated in the conjunctival sac of clinically normal dogs and dogs with ulcerative keratitis in Beijing, China. The likelihood of detecting bacteria depends on the season.     

Normal ocular features, conjunctival microflora and intraocular pressure in the Canadian beaver (Castor canadensis)

Objective The aim of the study was to assess the ocular features, normal conjunctival bacterial and fungal flora, and intraocular pressure (IOP) in the Canadian beaver (Castor canadensis). Sample population Sixteen, apparently healthy beavers with no evidence of ocular disease, and live‐trapped in regions throughout Prince Edward Island. Procedures The beavers were sedated with intramuscular ketamine (12–15 mg/kg). Two culture specimens were obtained from the ventral conjunctival sac of both eyes of 10/16 beavers for aerobic and anaerobic bacterial and fungal identifications. The anterior ocular structures of all beavers were evaluated using a transilluminator and slit lamp biomicroscope. Palpebral fissure length (11/16 beavers), and horizontal and vertical corneal diameters (10/16 beavers) were measured. IOPs were measured in both eyes of 11/16 beavers using applanation tonometry. Both eyes of 3/16 beavers and one eye of 1/16 beavers were dilated using topical tropicamide prior to sedation to effect timely maximal dilation. Culture specimens and IOPs were not evaluated in these four animals. Indirect ophthalmoscopy was performed on 7/8 eyes of these four beavers. Results Conjunctival specimens from all eyes cultured positively for one or more isolates of aerobic bacteria. The most common isolate was Micrococcus spp. (five beavers; 9/20 eyes). Other isolates included a Gram‐positive coccobacilli‐like organism (four beavers; 7/20 eyes), Aeromonas hydrophila (three beavers; 4/20 eyes), Staphylococcus spp. (three beavers; 4/20 eyes), Gram positive bacilli (one beaver; 2/20 eyes), Enterobacter spp. (two beavers; 2/20 eyes), Streptococcus spp. (two beavers; 2/20 eyes), aerobic diphtheroids (one beaver; 1/20 eyes), and Pseudomonas spp. (one beaver; 1/20 eyes). Clostridium sordellii (one beaver; 1/20 eyes) and Peptostreptococcus spp. (one beaver; 1/20 eyes) were the sole anaerobic bacteria isolated. All conjunctival specimens were negative for growth of fungi. Ophthalmic examinations revealed the normal beaver eye and ocular adnexa included dorsal and ventral puncta, a vestigial third eyelid, and a circular pupil. Average palpebral fissure length was 9.36 mm (SD = 1.00) for both eyes. Mean horizontal and vertical corneal diameters of both eyes were 9.05 mm (SD = 0.64) and 8.45 mm (SD = 0.69), respectively. Mean IOP for the right and left eyes were 17.11 mmHg (SD = 6.39) and 18.79 mmHg (SD = 5.63), respectively. Indirect ophthalmoscopic examinations revealed normal anangiotic retinas. Conclusions Gram‐positive aerobes were most commonly cultured from the conjunctival sac of normal beavers, with Micrococcus spp. predominating. The overall mean IOP in ketamine‐sedated beavers was 17.95 mmHg. The beaver, an amphibious rodent, has an anangiotic retina.