Bernhard M. Spiess

Guidelines for clinical electroretinography in the dog

These procedures described for the dog ERG were approved at the 1st European Conference on Veterinary Visual Electrophysiology in Vienna, Austria, May 30, 2000. Dr. Narfström was Chair of the Committee for a Harmonized ERG Protocol, appointed by the European College of Veterinary Ophthalmology (ECVO), and Dr. Ofri was secretary. The other coauthors are committee members. Guidelines for ERG procedures in other animal species for clinical and laboratory studies are planned for in the future and the present guidelines are planned to be revised on a biannual basis. A brief report of the recommended procedures is available in the Conference Proceedings book.

Evaluation of a rebound tonometer (Tonovet) in clinically normal cat eyes.

OBJECTIVE To determine the accuracy of and to establish reference values for a rebound tonometer (Tonovet) in normal feline eyes, to compare it with an applanation tonometer (Tonopen Vet) and to evaluate the effect of topical anesthesia on rebound tonometry. PROCEDURES Six enucleated eyes were used to compare both tonometers with direct manometry. Intraocular pressure (IOP) was measured in 100 cats to establish reference values for rebound tonometry. Of these, 22 cats were used to compare rebound tonometry with and without topical anesthesia and 33 cats to compare the rebound and applanation tonometers. All evaluated eyes were free of ocular disease. RESULTS Both tonometers correlated well with direct manometry. The best agreement with the rebound tonometer was achieved between 25-50 mmHg. The applanation tonometer was accurate at pressures between 0 and 30 mmHg. The mean IOP in clinically normal cats was 20.74 mmHg with the rebound tonometer and 18.4 mmHg with the applanation tonometer. Topical anesthesia did not significantly affect rebound tonometry. CONCLUSIONS As the rebound tonometer correlated well with direct manometry in the clinically important pressure range and was well tolerated by cats, it appears suitable for glaucoma diagnosis. The mean IOP obtained with the rebound tonometer was 2-3 mmHg higher than that measured with the applanation tonometer. This difference is within clinically acceptable limits, but indicates that the same type of tonometer should be used in follow-up examinations in a given cat.

Corneal collagen cross-linking (CXL) for the treatment of melting keratitis in cats and dogs: a pilot study

OBJECTIVE UV-A/riboflavin cross-linking (CXL) of corneal collagen fibers is an established, highly promising therapy for corneal melting in physician-based ophthalmology. A prospective pilot study was conducted to demonstrate proof of principle of this novel method for the treatment of melting corneal ulcers in dogs and cats. PROCEDURES After obtaining owner consent, CXL was performed in three cats and three dogs with corneal melting, which either affected the entire corneal surface or was resistant to conventional antibiotic and anticollagenolytic therapy, and affected parts or all of the corneal surface. Medical therapy was continued in all patients. The available follow-up ranged from 2 to 22.5 months and involved slit-lamp examination, fluorescein staining, and photographic documentation during all rechecks. RESULTS Surgical stabilization of the cornea was not necessary in any case, because progression of corneal melting was arrested in all cases within 1-20 days of CXL treatment. Corneal re-epithelization occurred within 7-40 days in all eyes. At 40 days after CXL, all eyes presented a quiescent corneal state without signs of active inflammation and with beginning scar formation. The complications observed in three of the six animals included a corneal sequestrum, superficial corneal stromal pigmentation, and bullous keratopathy. CONCLUSIONS This study shows the feasibility of CXL to treat progressive corneal melting in veterinary patients. CXL may represent a cost-efficient and safe alternative therapy in the treatment for corneal melting in veterinary ophthalmology. More investigations comparing the effectivity and complication rate of CXL to those of standard medical treatment are necessary.

Equine keratomycosis in Switzerland: A retrospective evaluation of 35 horses (January 2000–August 2011)

REASON FOR PERFORMING STUDY Keratomycosis is a severe disease in horses. Geographical differences in fungi causing keratomycosis and susceptibility of the organisms to antifungal drugs exist but few previous publications on this disease originate from Europe. OBJECTIVE To retrospectively compare the clinical data of 36 eyes with keratomycosis, diagnosed in 35 horses between January 2000 and August 2011 at the Vetsuisse Faculty of Switzerland. Case history, season, prior treatment, clinical appearance, surgical and medical treatment, treatment duration, and globe survival were evaluated. STUDY DESIGN Retrospective case series. METHODS Medical records of horses with a definitive cytological or histological diagnosis of keratomycosis were reviewed. RESULTS Thirty-one of 36 eyes (86.1%) presented with ulcerative keratitis, 2/36 (5.55%) had diffuse corneal infiltration, 2/36 (5.55%) had superficial punctate keratitis and 1/36 (2.8%) had a fluorescein-negative fungal plaque. Two of 6 fungal cultures produced Aspergillus spp. Thirty eyes received medical and surgical treatment, while 3 eyes were treated medically only. In 3 horses the globe was removed at the time of first presentation. Sex, age, prior treatment with antimicrobials or steroids, or type of surgical approach did not significantly influence the outcome. Twenty-three of 36 eyes (63.9%) were at least partially visual, 11/36 eyes (30.5%) were enucleated and 2 horses (2/36 eyes, 5.6%) were subjected to euthanasia. Treatment protocols were compared in the 31 eyes with ulcerative keratitis. In this group, 3/31 globes were immediately enucleated, 16/31 eyes were treated topically with voriconazole or voriconazole/fluconazole and 12/31 with other antifungal drug combinations. The different medication protocols did not significantly affect the outcome. CONCLUSIONS There were no significant differences in outcome between different medical treatment protocols or types of surgical approach. POTENTIAL RELEVANCE Future studies in central Europe should focus on the identification of fungal pathogens, susceptibility patterns and the efficacy of antifungal drug therapies.

Epidemiology of canine glaucoma presented to University of Zurich from 1995 to 2009. Part 1: Congenital and primary glaucoma (4 and 123 cases).

OBJECTIVE To investigate the epidemiology of canine congenital and primary glaucoma in the cases presented to the University of Zurich, Vetsuisse Faculty (UZH) from 1995 to 2009. METHODS Information was obtained from the computer database of patients examined by members of the UZH Ophthalmology Service, between January 1995 and August 2009. Congenital and primary glaucoma was diagnosed based on the age of onset, the lack of evidence of any antecedent eye conditions, and/or the presence and severity of iridocorneal angle defects. The data was evaluated for breed, gender and age at presentation. RESULTS A total of 5984 dogs presented to the UZH Ophthalmology service between 1995 and 2009. Four dogs of different breed were diagnosed with congenital glaucoma and 123 dogs were diagnosed with primary glaucoma. For the primary glaucomas the overall male to female ratio (M:F) was 1:1.41 and the age of onset ranged from 0.12 to 18.3 years with a mean of 7.3 ± 3.6 years. Data suggested a predisposition for primary glaucoma in the Siberian Husky, Magyar Vizsla and Newfoundland from 2004 to 2009. CONCLUSION The report presents the epidemiology of canine congenital and primary glaucomas presented to the UZH from 1995 to 2009. A previous suspicion of predisposition for primary glaucoma in the Newfoundland dog (n = 6) and the Magyar Vizsla breed (n = 8) was confirmed.

Effects of topical administration of 1% brinzolamide on intraocular pressure in clinically normal horses

REASONS FOR PERFORMING STUDY Only few drugs with limited efficacy are available for topical treatment of equine glaucoma. OBJECTIVE To evaluate the effect of topical administration of 1% brinzolamide on intraocular pressure (IOP) in clinically normal horses. METHODS Healthy mature horses (n = 20) with normal ocular findings, were studied. The IOP was measured 5 times daily (07.00, 11.00, 15.00, 19.00 and 23.00 h) over 10 days. On Days 1 and 2, baseline values were established. On Days 3-5 one eye of each horse was treated with one drop of 1% brinzolamide every 24 h immediately following the 07.00 h measurement. On Days 6-8 the same eye was treated with 1% brinzolamide every 12 h (07.00 and 19.00 h). Measurements on Days 9 and 10 documented the return of IOP to baseline values. Statistical analysis of the data was performed. RESULTS In the treated eye a significant decrease in IOP compared to baseline values was noted during both the 24 and 12 h dosing periods (P < 0.001). During the once-daily treatment protocol an IOP reduction of 3.1 +/- 13 mmHg (14%) from baseline was recorded. During the twice-daily protocol a total IOP reduction of 5.0 +/- 1.5 mmHg (21%) was achieved. CONCLUSION Intraocular pressure was significantly decreased by 1% brinzolamide in a once-daily and a twice-daily treatment protocol in normotensive eyes. These findings suggest that brinzolamide might also be effective in horses with an elevated IOP. POTENTIAL RELEVANCE This drug may be useful for treatment of equine glaucoma.

Corneal collagen cross-linking as treatment for infectious and noninfectious corneal melting in cats and dogs: results of a prospective, nonrandomized, controlled trial.

OBJECTIVE UV-A/Riboflavin cross-linking of corneal collagen fibers (CXL) is a highly promising therapy for corneal melting in humans. A prospective interventional, nonrandomized, controlled study was conducted to compare the stabilizing effect of CXL treatment on melting keratitis in dogs and cats and the complication rate of CXL to those of standardized intensive medical treatment. PROCEDURES Forty-nine eyes with melting keratitis were included in the study between October 2009 and October 2012. All eyes were treated according to the same medical treatment protocol. Nineteen eyes were CXL-treated, and 30 eyes were not. Follow-up included slit-lamp examination, fluorescein staining, ulcer size measurement, stromal stability evaluation, photographic documentation, and documentation of complications. RESULTS Five of 19 eyes in the CXL group and 9/30 eyes in the control group required rescue stabilization due to continued melting. Seven of the nine control group corneas stabilized after rescue CXL treatment. At initial presentation, the ulcers in the canine CXL group were significantly deeper and larger than in the control group. Ulcer deepening during follow-up was more pronounced in the canine control group than in the canine CXL group. CXL treatment-related complications were not observed. CONCLUSIONS Based on the similar failure rates in the control and CXL treatment groups despite the poorer initial situation in the CXL group, the tendency for the ulcers in the control group to deepen and the stabilization of all corneas receiving CXL rescue treatment, we believe that CXL has its place as an adjunctive therapy for melting keratitis in veterinary ophthalmology.

Canine neurogenic Keratoconjunctivitis sicca: 11 cases (2006–2010)

OBJECTIVE   To describe the clinical data of dogs with neurogenic Keratoconjunctivitis sicca (KCS) and an ipsilateral dry nose without other neurologic deficits. PROCEDURE   The retrospective case study included 11 dogs diagnosed with neurogenic KCS and an ipsilateral dry nose between 2006 and 2010. Medical records were reviewed for breed, age, sex, history, suspected cause of neurogenic KCS, clinical signs, and treatment modalities. Follow-up information was obtained by re-examination of patients or completion of a telephone survey with the referring veterinarian or the owners. RESULTS   Mean age of the dogs was 6.6 ± 4.5 years. Neurogenic KCS was diagnosed in three females, five spayed females, one male, and two castrated males representing 10 different breeds. Ophthalmic signs of KCS (mean Schirmer tear test [STT] value of 1.9 ± 2.9 mm/min) combined with an ipsilateral dry nose were diagnosed in seven left and four right eyes. The suspected cause of neurogenic KCS was idiopathic in nine and trauma in two cases. Systemic therapy consisted of oral pilocarpine 1-2% eye drops combined with case-specific topical treatment with cyclosporine 0.2% and tear substitutes. Duration of systemic treatment with pilocarpine until healing was 125 days (range 84-204, median 98 days) for five dogs. One dog was lost to follow-up, and the remaining five dogs are still under systemic treatment with pilocarpine. CONCLUSIONS   Neurogenic KCS with an ipsilateral dry nose seems to be a predominantly idiopathic disease of middle-aged female dogs without breed predisposition, which may be self-limiting in some cases.

Parachlamydia acanthamoebae in domestic cats with and without corneal disease

Corneal samples of cats with and without corneal diseases were screened with a pan-Chlamydiales PCR and specific PCRs for Parachlamydia, Protochlamydia, Chlamydophila felis, Acanthamoeba and feline herpesviruses (FHV-1). Several corneal samples tested positive for Parachlamydia and related Chlamydiales, indicating cat exposure to these intracellular bacteria.

Prevalence of nuclear cataract in Swiss veal calves and its possible association with mobile telephone antenna base stations

The purpose of this study was to valuate the prevalence of nuclear cataract in veal calves and to elucidate a possible impact by mobile phone base stations (MPBS). For this experiment a cohort study was conducted. A follow-up of the geographical location of each dam and its calf from conception through the fetal period up to slaughter was performed. The first trimester of gestation (organogenesis) was particularly emphasized. The activities of selected protective antioxidants (superoxide dismutase, catalase, glutathione peroxidase [GPx]) were assessed in aqueous humor of the eye to evaluate the redox status. Of 253 calves, 79 (32 %) had various degrees of nuclear cataract, but only 9 (3.6 %) calves had severe nuclear cataract. Results demonstrate a relation between the location of veals calves with nuclear cataracts in the first trimester of gestation and the strength of antennas. The number of antennas within 100 to 199 meters was associated with oxidative stress and there was an association between oxidative stress and the distance to the nearest MPBS. Oxidative stress was increased in eyes with cataract (OR per kilometer: 0.80, confidence interval 95 % 0.62,0.93). It has not been shown that the antennas actually affected stress. Hosmer-Lemeshow statistics showed an accuracy of 100 % in negative cases with low radiation, and only 11.11 % accuracy in positive cases with high radiation. This reflects, that there are a lot of other possibilities for nuclear cataract beside MPBS. Further studies on the influence of electromagnetic fields during embryonic development animal or person at risk are indicated.