Outcome of superficial keratectomy without conjunctival graft as a surgical technique for immune‐mediated keratitis in horses: Four cases

This case report describes four horses with unilateral superficial or mid-stromal immune-mediated keratitis (IMMK) treated with a superficial keratectomy (SK) without a conjunctival graft. In two horses, the surgery was performed under general anaesthesia, and in two horses standing with sedation and local blocks. Results of this report show that SK is a viable treatment option in horses with chronic superficial and/or mid-stromal IMMK that can even be performed in the standing, sedated horse. When sufficient corneal tissue is removed, no recurrence is to be expected in the long-term follow-up (up to 31 months). In two horses, healing occurred without complications. Two horses developed a secondary bacterial infection post-operatively (Enterococcus faecalis and Staphylococcus aureus). In one case, this resulted in a pre-perforating melting corneal ulcer necessitating conjunctival pedicle graft surgery 13 days post keratectomy. In three horses, there was no recurrence of the IMMK with a long-term follow-up of 6–31 months. One case showed recurrence of IMMK in the cornea region surrounding the keratectomy 9 months after surgery

Non-invasive diode laser, an effective and safe treatment of iris cysts in 46 eyes of 35 horses

Background: Iris cysts in horses are often asymptomatic and noticed incidentally. However, cysts can cause local corneal oedema and erratic behaviour like shying, decreased performance and head-shaking. Objectives: To describe the use of diode laser as a noninvasive treatment option for iris cysts in the horse and to document factors influencing its efficacy, associated complications, long-term outcome and rate of recurrence. Study design: Retrospective case series. Methods: Case records of horses treated for iris cysts by diode laser at the Utrecht University Equine Clinic were reviewed between 2008 and 2020. Diagnosis was based on ophthalmic and ultrasonographic evaluation. Long-term follow-up was obtained in two phases, a telephone survey with the owner and a photographic re-evaluation of the treated eyes. Results: Thirty-five horses were included, with a total of 46 eyes treated. One day after diode laser treatment (short-term), 35/46 treated eyes had a good decrease in cyst size, 7/46 had a moderate effect, 1/46 had a minimal effect, 1/46 had no effect, and in two cases the effect was unspecified. The decrease in size after diode laser treatment in polycystic eyes (odds ratio [OR] 0.381, 95% CI 0.1530–0.724), p = 0.001), thick-walled cysts (OR = 0.139; CI = 0.023–0.726, p = 0.02) and hyperplastic corpora nigra (OR = 0.081; CI = 0.004–0.528, p = 0.03) was significantly less satisfactory, with ORs of 0.381, 0.139 and 0.081, respectively. Minor complications, such as mild reactive uveitis, were reported in 8/46 (17%) eyes. On long-term follow-up (median 19 months; IQR 25.5), clinical signs had diminished or disappeared in most cases (93%) and 83% of the owners would recommend the treatment. Based on long-term photographic re-evaluation (median 32.5 months; IQR 49.75), 2/16 cases of recurrence were seen. Main limitations: Retrospective design, follow-up by telephone questionnaire and photographic re-evaluation. Loss to follow-up in the photographic re-evaluation. Conclusions: Both short- and long-term results indicate diode laser treatment is a useful and safe option for iris cyst size reduction, with a low risk of recurrence. Presurgical ultrasonography is recommended to assess the feasibility of treatment and to allow for better surgical planning

Penetration of topically administered dexamethasone disodium phosphate and prednisolone acetate into the normal equine ocular fluids

Background: Topical dexamethasone and prednisolone are currently the mainstay treatment for equine ophthalmic inflammatory diseases, such as equine recurrent uveitis. Comparative pharmacokinetic studies in horses are lacking and current guidelines are mainly based on empirical data and extrapolation from other species. Objectives: To investigate the penetration and local concentrations of topically applied dexamethasone and prednisolone in normal equine ocular fluids and serum. Study design: Prospective randomised experimental pharmacokinetic study. Methods: Twenty-one Shetland ponies without ophthalmic disease were treated bilaterally topically every 2 hours during 24 hours to obtain steady state drug concentrations. One eye was treated with 0.15 mg of dexamethasone disodium phosphate (0.1%), and the other eye was simultaneously treated with 1.5 mg of prednisolone acetate (1%). Serum samples were taken prior to the induction of general anaesthesia. Aqueous and vitreous humour samples were taken during euthanasia at time points after administration of the last dose (t = 5 min, t = 15 min, t = 30 min, t = 60 min, t = 90 min, t = 120 min, t = 180 min). Each pony was randomly assigned to one time point, and three ponies were sampled per time point. Dexamethasone and prednisolone concentrations were measured by liquid chromatography-mass spectrometry. Results: The mean dexamethasone concentration in aqueous humour was 32.4 ng/mL (standard deviation [SD] 10.9) and the mean prednisolone concentration was 321.6 ng/mL (SD 96.0). In the vitreous and in serum samples concentrations of both corticosteroids were below the limit of detection (LOD 2.5 ng/mL). Main limitations: The study group was limited to subjects without evidence of current ophthalmic disease. A limited number of time points were measured. Conclusions: Potentially effective dexamethasone and prednisolone concentrations were measured in the anterior chamber, but vitreal concentrations were negligible. Systemic uptake was low. Therefore, treatment with only topically administered corticosteroids is deemed insufficient in horses in cases of posterior uveitis. Further studies evaluating other routes of administration are warranted

More than meets the horse’s eye: An insight into equine ophthalmology

The prevalence of ophthalmic abnormalities in horses is high, higher even than most people are aware of and this is why equine ophthalmology has increasingly become a focus of attention. Loss or impairment of vision of horses has negative consequences for performance, usability and welfare. This thesis comprises work that arose from research questions related to clinical (eye)problems encountered in daily equine practice and is divided in 3 parts. The first part is focused on unravelling of a genetic ophthalmic disease in the horse, namely distichiasis. In distichiasis, extra eyelashes grow from the tarsal glands on the eyelids. The treatment, long-term follow-up and the identification of the genomic regions associated with distichiasis have been described. Aspects of pharmacokinetics of corticosteroids, one of the most commonly used anti-inflammatories for the equine eye, have been addressed in the second part. The distribution into the different compartments of the equine eye of corticosteroid eye drops (dexamethasone and prednisolone) and oral corticosteroids (prednisolone) have been investigated. The third part focuses on anaesthesia, improving local anaesthetic techniques and adequate analgesia during and after (standing) surgical ophthalmic procedures in horses. This thesis sheds light on the genetic cause of an important ophthalmic disease like distichiasis in the horse, helps to improve evidence-based medical and surgical treatment, and provides a vision for further research and future perspectives for prevention and treatment of diseases of the equine eye

Adolescents' responses to a school-based prevention program promoting healthy eating at school

Contains fulltext : 178856.pdf (publisher's version ) (Open Access)Background: To improve the effectiveness of school-based obesity prevention programs, it is essential to understand the views and behaviors of the target group. The present study aimed to get a better understanding of adolescents' food and health perceptions and their willingness to be involved in a specific school-based prevention program, i.e., the Dutch 'Healthy School Canteen Program'. Methods: The present study used a mixed methods research design. First, seven semi-structured focus groups were conducted using a selective sample of 42 Dutch adolescents (24 girls, 18 boys, aged 13-16 years). Second, an online survey among 133 adolescent respondents (72 girls, 61 boys, aged 12-19 years) using snowball sampling was conducted. Content analysis was performed to make inferences about the focus group discussions, whereas statistical analyses were conducted to analyze the survey data. Results: Findings from the group discussions indicated that healthy eating was only an issue of importance when adolescents perceived negative physical changes (e.g., with regards to looks or physical performance). Adolescents also indicated that they clearly wanted to make their own food and drink choices at school. The quantitative data indicated that taste, price and variety were seen as the most important aspects of a healthy food assortment (mean scores 8.1, 7.8 and 7.7 on a 10-point scale respectively). In general, most adolescents (64%) expressed that students should be involved in the organization of a healthy food environment in schools. At the same time, however, adolescents were not willing to participate themselves. This was mostly because they were skeptical about their ideas being heard and put into action by their schools. Conclusions: School-based prevention programs, such as the Healthy School Canteen, should take into account that adolescents have a low risk perception of unhealthy eating and are seeking food choice autonomy. In addition, schools should not lose sight of product price, taste, and variety to make their food assortment attractive to students. If schools aim to involve adolescents in universal prevention programs that promote healthy eating, it is essential that they have a formal student involvement process that ensures that adolescents' suggestions are valued.11 p

A retrospective analysis of the risk factors for surgical site infections and long-term follow-up after transpalpebral enucleation in horses

BACKGROUND: Implants are often used to improve the cosmetic appearance of horses after enucleation of the eye. When surgical site infection (SSI) occurs, the implant will almost always be lost. The aim of this study is to collect data on the risk factors for SSIs and report long-term follow-up (cosmetic results and return to work) after transpalpebral enucleations. In this retrospective study, records of horses undergoing transpalpebral enucleation were reviewed (2007-2014) and telephone interviews were used to obtain long term follow-up. The potential risk factors for SSIs (indication for enucleation, use of an implant, standing procedures, duration of surgery, opening of the conjunctival sac and prolonged use of antimicrobials) were analysed for their association with the outcome measure 'SSI' vs 'no SSI' by multivariable binary logistic regression testing. Indications for enucleation were grouped as follows: Group 1 (clean) included equine recurrent uveitis, too small or too large globes, and intraocular tumours, Group 2 (non-clean) included corneal perforation/rupture and infected ulcers and Group 3 (tumour) included extraocular tumours. RESULTS: One hundred and seven cases of enucleation were evaluated. An implant was used in 49 horses. The overall number of SSIs was 8 (7.5%). Multivariable logistic regression testing showed implants (OR 7.5, P = 0.04) and standing procedures (OR 12.1; P = 0.03) were significantly associated with the percentage of SSIs and increased the risk of SSI. The eyes of horses in Groups 2 and 3 trended towards a larger risk for developing SSIs (OR 4.9; P = 0.09 and OR 5.9; P = 0.1, respectively). Prolonged use of antimicrobials, long surgery times and the opening of the conjunctival sac during dissection did not show significant associations with SSI risk. CONCLUSIONS: The risk of SSI after enucleation is low in clean eyes and when no implant is used. Placing an implant or performing a standing enucleation significantly increases the risk of SSIs. Although implants can be used for eyes that fall into Groups 2 and 3, 17% of the horses in these two groups developed an SSI leading to loss of the implant

Morphological variations of the infraorbital canal during CT has limited association with headshaking in horses

Headshaking is a common problem in horses. The etiology is unknown but thought to involve sensory input from branches of the trigeminal nerve, some of which are within the infraorbital canal. The objective of this retrospective cross-sectional study was to describe the CT anatomy and variations of the infraorbital canal in horses with local disease processes and normal horses, and to examine associations between those findings and headshaking. Computed tomography scans were reviewed and morphological changes of the infraorbital canal were described. Presence of changes was then tested for association with headshaking prevalence, presence of disease processes in the region of the infraorbital canal, age, and sex. Nonparametric tests were used and a P-value of .05 was considered significant. A total of 218 horses were included, 9% of which had headshaking and 45% had CT lesions in the region of the infraorbital canal. Morphological changes to the bone of the infraorbital canal were found in 121 horses (56%) and included the following: increased mineralization 39 (18%), decreased mineralization 89 (41%), deformed shape 51 (23%), displaced position 43 (20%), and disruption 11 (5%). All changes of the infraorbital canal significantly increased in frequency with the presence of adjacent disease. Increased mineralization and disruption of the infraorbital canal were significantly associated with headshaking in horses with adjacent disease; the latter only reached significance after exclusion of dentally immature horses. No other changes were significantly associated with the presence of headshaking. No association was found between headshaking and the age or sex of the horse