Corneal Cytology Research Articles

Histopathological features of equine superficial, nonhealing, corneal ulcers.

To evaluate corneal changes associated with chronic, nonhealing, superficial, corneal ulcers in horses via common histopathological stains. Retrospective study. Twenty-four horses diagnosed with chronic, nonhealing, superficial, corneal ulceration. The medical records of horses evaluated at North Carolina State University's Veterinary Teaching Hospital (NCSU-VTH) from 2005 to 2011, diagnosed with a chronic, nonhealing, superficial, corneal ulcer and treated with superficial keratectomy (SK) were reviewed. Inclusion criteria were superficial corneal ulceration, no cellular infiltration via slit-lamp biomicroscopy, no microorganisms evident on corneal cytology, and acquisition of samples for aerobic bacterial and common fungal cultures. Corneal tissue samples were evaluated histopathologically for the presence or absence of a nonadherent epithelial 'lip', epithelial dysmaturity, intraepithelial inflammatory cells, an acellular hyaline zone in the anterior stroma, and stromal inflammatory cells, fibrosis and vascularization. In the majority of analyzed samples, epithelial cells adjacent to the ulcerated site showed nonadherence to the basement membrane and dysmaturity. Intraepithelial inflammatory cell infiltration was uncommon. Histopathological features of an anterior stromal hyaline zone, intrastromal inflammation, fibrosis and vascularization were variably present. The most consistent histopathological characteristics of equine chronic, nonhealing, superficial, corneal ulcers include epithelial nonadherence, epithelial dysmaturity and mild to moderate stromal inflammation; however, one set of histopathological characteristics does not definitively define this syndrome in horses. Additionally, the anterior stromal acellular hyaline zone commonly cited in canine spontaneous chronic corneal epithelial defects (SCCED) is not a consistent finding in equine corneas.

Feline eosinophilic keratoconjunctivitis: a retrospective study of 45 cases (56 eyes).

The medical records of 45 cases (56 eyes) of feline eosinophilic keratoconjunctivitis (EKC) diagnosed between 2005 and 2011 were reviewed. Cats were included if a clinical diagnosis of EKC was recorded and eosinophils were found on corneal cytology. Median age at presentation was 5 years (interquartiles 5-9 years) for both males and females. Domestic shorthair was the predominant breed, accounting for 77.8% of the cats. The condition was unilateral in 75.6% of cases, with the superotemporal quadrant of the cornea the most frequently affected position (76.8% of eyes). A history of corneal ulceration was recorded in 37.8% of cases, and corneal ulcers were present at or before diagnosis in 66.7% of the cats. Eosinophils were found in 92.0% of conjunctival scrapings. We performed polymerase chain reaction (PCR) for feline herpesvirus type 1 (FHV-1) for 33/45 cats. Viral DNA was detected in 54.5% of these cats. FHV-1 DNA was detected by PCR in 66.7% of cats with a history and/or presence of a corneal ulcer at first presentation, which is significantly more than those with no corneal ulcer at any time (22.2% FHV-1 DNA detected). Our findings suggest that a corneal ulcer can be present prior to the development of eosinophilic keratitis. Further studies are mandatory to explore the role that FHV-1 could play in EKC-associated corneal ulceration.

Scedosporium apiospermum keratomycosis in a dog

A 6-year-old male castrated Norfolk Terrier dog was examined following a 21-day history of an increasingly painful eye. Examination revealed marked blepharospasm and purulent ocular discharge associated with an ulcerative keratitis. There was panstromal corneal opacity with raised gray to white lesions. Corneal cytology demonstrated branching septate fungal hyphae identified by polymerase chain reaction as Scedosporium apiospermum. Treatment with topical 1% voriconazole solution was successful in resolving the keratomycosis.

Acremoniumkeratomycosis in a cat

A 14-year-old, female spayed Domestic Short-haired cat was presented for evaluation of progressive superficial corneal ulceration with mucoid ocular discharge, blepharospasm, and conjunctival hyperemia OD. Upon examination, ulcerative keratitis with stromal loss, chemosis, corneal edema, miosis, aqueous flare, and hyphema were noted. Corneal cytology revealed branching, septate fungal hyphae with bulbous terminations and associated ovoid structures, with suppurative inflammation. Fungal culture of corneal swabs confirmed the presence of Acremonium, although PCR of the cytology sample was negative. Ten days of treatment with topical 1% miconazole resulted in clinical deterioration before switching to topical 1% voriconazole solution, which was successful in resolving the infection. The apparent clinical efficacy of the topical antifungals used contrasted with the in vitro susceptibility profile.

Equine corneal and conjunctival cytology: Practical tips

Cytology is a simple economical procedure which may provide rapid diagnostic information for horses suffering from ocular surface disease. Collection of diagnostically useful specimens is the key initial step in cytology. The technique used will vary depending on the nature of the ocular surface disease and consideration of the pros and cons of different sampling methods. This manuscript provides with some tips on how to perform corneal and conjunctival cytology and when it can be useful. Different instruments which may be used to perform the sampling are also described. The authors have added a clinical case to emphasize how important cytology can be in both the diagnosis and treatment of surface ocular disease.

Clinical features and outcomes of severe ulcerative keratitis with medical and surgical management in 41 horses (2000–2006)

SummaryThe clinical features and outcomes of equine ulcerative keratitis with and without conjunctival graft surgery were assessed using a retrospective study.Medical records of horses hospitalised from July 2000‐January 2006 for ulcerative keratitis were included if a diagnosis of melting ulcer, descemetocele or iris prolapse was made, or if surgery was recommended due to severity of corneal disease, and aggressive medical therapy using a subpalpebral catheter was instituted. Treatment and outcome variables were evaluated with and without conjunctival graft surgery.Forty‐one horses, 21 that had surgery and 20 for whom surgery was recommended but not performed, were included. Horses were hospitalised for an average of 24 days, with 37/41 melting ulcers, 17/41 descemetoceles and 3/41 iris prolapses, with no statistical difference in frequencies between groups. Bacterial or fungal organisms were cultured from 22/39 cases, with 10Aspergillusspp. and 8Pseudomonasspp. Infectious organisms were seen on corneal cytology in 23/30 cases. Surgical cases were hospitalised for an average of 4.9 days prior to surgery. Abdominal discomfort was observed in 8/41 hospitalised horses, with 5/8 operated horses developing caecal impactions. Thirty‐five horses retained an intact globe, including 18/20 treated medically and 17/21 that had surgery. Hospitalisation cost was 24% more for cases that had surgery than for medical cases.It was concluded that there was no statistical difference in length or cost of hospitalisation between surgical and nonsurgical groups. Outcomes from both groups were similar, with a high frequency of globe retention.

Treatment of proliferative feline eosinophilic keratitis with topical 1.5% cyclosporine: 35 cases

Proliferative feline eosinophilic keratitis is a chronic keratopathy caused by a suspected immune mediated response to an unknown antigenic stimulus. The purpose of this study is to demonstrate the efficacy of topical 1.5% cyclosporine solution in proliferative feline eosinophilic keratitis. Thirty-five cats were treated topically with 1.5% cyclosporine A between 1997 and 2007. Eosinophilic keratitis was diagnosed by clinical appearance and evidence of eosinophils and/or mast cells in corneal cytology. The patients were treated with topical cyclosporine (1.5%) twice (26 of 35, 74.3%) and three times (9 of 35, 25.7%) daily. The minimum period for follow-up was 5 months. The age of the patients ranged from 2 to 13 years with a mean age of 6.0 years. Twenty-two were neutered males, and 13 were females. The represented breeds were 30 DSH, 3 DLH, one Siamese and one Maine Coon. Cytologic examination of a corneal scrape revealed the presence of eosinophils in 34 of 35 specimens, and mast cells in 25 of 35 specimens. Improvement in the treated eyes was seen in 31 cats (88.6%). Four animals (11.4%) did not respond to the treatment with topical cyclosporine. Recurrences were seen in seven (22.6%) cases. Blepharitis was noted as an infrequent side effect. Based on our findings, topical cyclosporine (1.5%) is an effective treatment of proliferative feline eosinophilic keratitis in the vast majority of cases. Recurrences were mainly associated with poor owner compliance. Chronic, often lifelong therapy with medications is thus recommended.

Topical use of Nerve Growth Factor on ocular flora and cytology in dogs eye surface

Abstract Purpose To investigate if topical Nerve Growth Factor (NGF) affects the ocular flora and to study corneal conjunctival cytology in dogs with different eye surface disease. Methods The present study has been conducted on 9 dogs (18 eyes) affected by different ocular surface disease. The dogs were various ages (from 2 to 10 years old) and different sexes (5 males ‐ 4 females). 6 dogs were affected by dry eye, 1 had a superficial keratitis and 2 dogs had a cornea ulcer. All dogs underwent the following examinations: cornea evaluation by slit lamp, fluorescent staining, Schirmer tear test I (STT I), corneal and conjunctival cytology. All samples made with ocular swabs were placed in a sterile blood agar. 6 dogs showed no bacteria, 3 dogs displayed Staphylococcus spp. Cytology pointed out many inflammatory cells. The dogs were topically treated with purified murine NGF diluted in paraffin oil (200 microg/ml) for 4 weeks (50 microg every 12 h). Results The result revealed that all swabs were sterile, while the cytology analysis showed a significant reduction in the number of corneal inflammatory cells. This latter observation is related to a decrease of the corneal inflammatory reduction. Conclusion This report demonstrated that NGF exerts an antibacterial and anti inflammatory activity that confirmed and extended previous evidences on NGF research. Moreover, our results suggest a potential therapeutic use of NGF in dogs with different ocular inflammatory surface. However, further clinical studies need to be done to assess the consistency of this clinic approach.

Analysis of Corneal Surface Evolution After Moderate Alkaline Burns by Using Impression Cytology

To compare corneal surface evolution after moderate alkaline burns by impression cytology in patients treated with medical therapy or with amniotic membrane transplantation (AMT). A prospective study of 24 eyes from 18 patients (13 men and 5 women) with moderate alkaline burns was performed. All patients were divided according to the clinical ocular severity and the therapy used. Twelve eyes were treated surgically with AMT and the other 12 eyes received only medical therapy. Corneal cytology was obtained immediately after the burns, and 1, 2, 5, and 9 months later. We differentiated between samples obtained from affected areas and areas not affected by the burns. Cellular size, nuclear size, and nuclear-cytoplasmic (N:C) ratio were examined in corneal epithelial cells, as was the presence of goblet cells in corneal epithelium. Nuclear size, cellular size, and N:C ratio in non-burn-affected corneal areas had no significant alterations in comparison with normal eyes. In contrast, in burn-affected corneal areas, these parameters were significantly worse, and the presence of goblet cells in corneal epithelium was frequent 1 month after severe burns. Cellular size, nuclear size, N:C ratio, and corneal conjunctivalization improved during the study in all patients, but corneal reepithelialization occurred earlier in patients treated with AMT than in patients with only medical therapy. Morphologic and morphometric analysis of corneal cells by impression cytology after ocular burns permits the establishment of cellular reepithelialization patterns in relation with limbal deficiency level and with clinical ocular severity. AMT improves corneal reepithelialization earlier than medical therapy in moderate alkaline burns.

Determinación del grado de metaplasia escamosa del epitelio corneal como factor diagnóstico de insuficiencia limbal

To determine the correlation between the squamous metaplasia grade of the corneal surface and the clinical severity of the limbal deficiency in patients with this disorder. We studied 98 eyes of patients with limbal deficiency by impression cytology. These patients were divided into four groups in relation to their clinical severity: 14 eyes had no symptoms, 34 eyes showed a mild grade of limbal deficiency, 28 eyes had a moderate grade and 22 eyes had severe limbal deficiency. Corneal cytology was performed in each patient. Cellular size, nuclear size, nuclear changes and the nuclear-cytoplasmic (N:C) ratio were defined in corneal epithelial cells, in addition to evaluation for the presence of goblet cells in the corneal epithelium. In patients with limbal deficiency without symptoms, we found that the cellular size was 477 (SD140) microm2 and the N:C ratio was 1:5.25 (SD1.5). In patients with mild limbal deficiency, the cellular size was 764 (SD122.6) microm2 and the N:C ratio was 1:8.2 (SD1.4). These patients did not show corneal conjunctivalization. In patients with moderate limbal deficiency the cellular size was 1,162 (SD340.2) microm2 and the N:C ratio was 1:13.2 (SD3.6). Some patients showed corneal conjunctivalization that was defined by the presence of goblet cells in the corneal epithelium. In patients with severe limbal deficiency, the cellular size was 2,036 (SD382) microm2 and the N:C ratio was 1:23.6 (SD4.0). Corneal conjunctivalization was present in all of these patients. There was a correlation between limbal deficiency severity and squamous metaplasia grade defined by impression cytology. Impression cytology was very useful for the diagnosis of cases of mild or subclinical limbal deficiency.

Corneal and Conjunctival Impression Cytology in Soft Contact Lens Wearers

This study assessed changes in corneal and conjunctional cytology in 25 soft contact lens (CL) wearers and compared them with matched controls. We found 80% of grade IV keratinization in CL users for more than 7 years. Keratinization was directly proportional to duration of CL use. Conjunctival cytological changes worsened with decreasing pH, whereas corneal keratinization showed no significant correlation.

Bacterial corneal diseases in dogs and cats

Corneal diseases are very common in small animals. Corneal disease associated with bacterial agents is frequent in the dog and maybe less frequent in the cat. The medical history, important steps of the ophthalmic examination, and the ophthalmic diagnostic tests that are relevant in such corneal conditions are outlined. Bacterial corneal diseases in dogs and cats are most commonly considered in one of two categories—bacterial ulcerative keratitis and corneal abscesses. The clinical aspects of these two entities as well as the therapeutic strategies available for general practitioners and ophthalmologists are discussed. Ulcerative keratitis is frequent; it represents the most common ocular diseases in dogs and cats. Because some of these corneal ulcers can be very severe, progress rapidly, and therefore are sight threatening, the crucial steps of their diagnosis and management are stressed. The use of a magnification system, fluorescein dye, and corneal cytology and culture, if indicated, is necessary for diagnosis at an early stage of the disease. The treatment of bacterial ulcerative keratitis should eradicate the infection, reduce or stop the corneal destruction and support the corneal structures, control the uveal reaction and the pain associated with it, and minimize the scarring. The prognosis depends on the stage and the severity of the corneal ulceration, the etiology of the condition, and the therapeutic choice. A close follow-up of animals with corneal ulceration is highly recommended because corneal ulcers can progress rapidly.

Short term wear of high Dk soft contact lenses does not alter corneal epithelial cell size or viability. Stapleton F, Kasses S, Bolis S, Keay L. Br J Ophthalmol 2001;85:143–146.

Current contact lenses (CLs) when worn on an extended wear basis cause corneal epithelial alterations. The aim of this study was to evaluate changes in corneal epithelial cell morphology and physiology following short term (three months) wear of highly oxygen permeable CLs and to compare this with disposable CLs. Subjects were wearers of highly oxygen permeable CLs (n = 11, wearing CLs on a 30 night schedule), disposable CL users (n = 6, wearing CLs on a six night schedule), and non-CL wearers (n = 20). Epithelial cells were harvested using corneal cytology and were stained using acridine orange and ethidium bromide. Epithelial cell size and viability were determined. The majority of epithelial cells recovered were non-viable (71%), and the mean longest cell diameter was 38 μm. Disposable CLs caused an increase in cell size compared with both non-wear and wear of highly oxygen permeable CLs. There was no difference in cell viability between groups. The authors conclude that extended wear of disposable CLs caused an 8% increase in cell diameter in harvested corneal epithelial cells following three months of CL wear. Cells harvested following three months’ wear of highly oxygen permeable CLs were indistinguishable from those recovered from non-CL wearers.—Thomas Liesegang.

Short term wear of high Dk soft contact lenses does not alter corneal epithelial cell size or viability

BACKGROUND/AIMSCurrent contact lenses (CLs) when worn on an extended wear basis cause corneal epithelial alterations. The aim of this study was to evaluate changes in corneal epithelial cell morphology and...

Rose bengal positive epithelial microerosions as a manifestation of equine keratomycosis.

Purpose To describe the clinical appearance of corneal epithelial cell microerosions associated with keratomycosis in the horse. METHODS: Retrospective clinical study. RESULTS: Multifocal, punctate, superficial corneal opacities with positive rose bengal retention were noted in six horses with presumed 'viral keratitis'. Faint fluorescein staining was also present in three cases. Equine herpesvirus tissue culture inoculation was negative for a cytopathic effect in three cases. Aspergillus (n = 3), Curvularia (n = 1), and an unidentified fungus (n = 1) were cultured in five horses, and hyphae found on corneal cytology from the sixth. Mixed bacterial infections were present in three eyes. The eyes of two horses with Aspergillus progressed to deep melting corneal ulcers that required surgical therapy. The microerosions remained superficial, but persistent in the other four eyes. Natamycin was utilized topically in all six horses. Transmission electron microscopy from case 6 revealed mucin layer disruption, an intact corneal epithelial cell layer, and fungal attachment to degenerating epithelial cells. The visual outcome was positive in all six horses, although healing was prolonged (48.5 +/- 14.5 days on average in the horses with no surgery; 62 days on average in the two horses that required surgery). CONCLUSIONS: Complete removal or full-thickness penetration of the corneal epithelial cell barrier may not be necessary to allow fungal adherence and initiation of keratomycosis in the horse. Prior to colonization and invasion of the horse cornea, fungi may induce changes in the mucin layer of the tear film that result in or are associated with rose bengal positive microerosions of the superficial corneal epithelium. Horses with painful eyes, and eyes with superficial, multifocal corneal opacities should have their corneas stained with both fluorescein and rose bengal as fungal microerosions may stain weakly, or not at all, with fluorescein, and may thus be mistaken for presumed 'viral keratitis' of the horse.

Rose bengal positive epithelial microerosions as a manifestation of equine keratomycosis

Abstract Purpose To describe the clinical appearance of corneal epithelial cell microerosions associated with keratomycosis in the horse. Methods Retrospective clinical study. Results Multifocal, punctate, superficial corneal opacities with positive rose bengal retention were noted in six horses with presumed ‘viral keratitis’. Faint fluorescein staining was also present in three cases. Equine herpesvirus tissue culture inoculation was negative for a cytopathic effect in three cases. Aspergillus (n= 3), Curvularia (n= 1), and an unidentified fungus (n= 1) were cultured in five horses, and hyphae found on corneal cytology from the sixth. Mixed bacterial infections were present in three eyes. The eyes of two horses with Aspergillus progressed to deep melting corneal ulcers that required surgical therapy. The microerosions remained superficial, but persistent in the other four eyes. Natamycin was utilized topically in all six horses. Transmission electron microscopy from case 6 revealed mucin layer disruption, an intact corneal epithelial cell layer, and fungal attachment to degenerating epithelial cells. The visual outcome was positive in all six horses, although healing was prolonged (48.5 ± 14.5 days on average in the horses with no surgery; 62 days on average in the two horses that required surgery). Conclusions Complete removal or full‐thickness penetration of the corneal epithelial cell barrier may not be necessary to allow fungal adherence and initiation of keratomycosis in the horse. Prior to colonization and invasion of the horse cornea, fungi may induce changes in the mucin layer of the tear film that result in or are associated with rose bengal positive microerosions of the superficial corneal epithelium. Horses with painful eyes, and eyes with superficial, multifocal corneal opacities should have their corneas stained with both fluorescein and rose bengal as fungal microerosions may stain weakly, or not at all, with fluorescein, and may thus be mistaken for presumed ‘viral keratitis’ of the horse.

Corneal brush cytology: an experimental study.

A total of 48 corneal smears from rabbits were obtained by means of brush, cotton swab and spatula techniques. The cytomorphologic features in those methods are compared. In the smears prepared by brush, numerous corneal epithelial cells were found. The cells were well spread in a single layer and overlapping was uncommon. The morphology of the corneal cells was satisfactory for cytologic evaluation. In contrast, the other two methods lacked adequate numbers of cells and cell preservation. We feel that corneal epithelial cells are readily obtainable by the brush method, compared with the cotton swab and spatula methods, and the material is also ideally suited for cytologic evaluation. It can be easily used for corneal cytology in clinical situations.