The treatment of periorbital equine sarcoids can be challenging for practitioners and owners as well. As reported for equine sarcoids in general, tumor growth is independent from gender and can affect horses at all ages. Furthermore the pathogenesis can be multifactorial and all six types reported in literature can occur (occult, verrucose, nodular, fibroblastic, mixed and malignant). The most common complications in correlation with sarcoids without or inadequate therapy are obstruction of the nasolacrimal duct, the functional impairment of the eyelids, exposure keratitis and as a possible result the loss of visual acuity. A total of 15 horses affected by periorbital sarcoids were introduced to the Tierarztliches Kompetenzzentrum Karthaus. Various, modern and already established therapy procedures were used in individual combination. Due to the localisation and restricted resection tissue complete regression could not be achieved by surgical excision alone. The tumor surface was revisoned by a diode laser 810 nm 30 W and fully removed in several sessions. Furthermore the diode laser was used as part of the photodynamic therapy including methylene blue derivate as a photosensitizer. The accumulation of methylene blue with light of specific wavelenght produces reactive oxide, which cause damage to tumour cells itself and the microvaskulature of neoplastic tissue. Chemotherapy included the intratumorale application of mitomycin 1 to 8 times every 2 to 3 weeks. Furthermore each patient received Aciclovir, an antiviral, as topical treatment once daily. Elaborately follw-up care and periodic checkups are essential to achieve satisfying long-term results. Of the 15 treated horses total regression was accomplished in 13 cases and no tumor recurrence could be detected during observation period of at least 11 months. In one advanced tumour case attenuation of symptomes was reported. Unfortunalety therapy was cancelled in one patient due to restricted financial means. The cases described above could reveal, that combined use of several modern therapy procedures, a so called multimodal therapy, represents an effective and targeted treatment of periorbital sarcoids in horses.

The advancement in veterinary medicine is driven by the specialisation of veterinarians. In the field of equine ophthalmology, this leads to a high number of patients referred to specialised veterinarians. The high number of patients, in turn, gives the opportunity to closely monitor certain diseases and develop targeted therapies. In the present work, based on human ophthalmology, a new eye disease in horses, vernal keratoconjunctivitis (keratoconjunctivitis vernalis-KCV), is described. The aim of the study is to define the disease which makes definitive diagnosis possible in the future, and to describe optimal therapy. The clinical presentation, differential diagnoses, histological findings, and the applied therapy are described on the basis of clinical data obtained from 22 patients (28 eyes). KCV is a chronic, immune-mediated conjunctival and corneal disease in horses. Affected patients show hyperaemia of the conjunctiva, signs of extreme ocular pain, blepharospasm and a thick, mucous epiphora. A varying degree of reflexive miosis is also visible in the eyes, depending on the severity of the disease. The clinical appearance is classified into a gigantopapillary type, a limbal type, and a mixed type. In the gigantopapillary type, typical changes are visible in the ventral conjunctiva. This appears through the pathognomonic, paving stone-like giant papillae. In the limbal type, in addition to the giant papillae, which look like a rosary in the limbus, cloudy, yellowish, round corneal changes, the so-called,Horner-Trantas dots" also appear. The changes can be further differentiated histologically. In one form, accumulated eosinophil cells are present. The other form is predominantly characterised by lymphocytes. Typical white, granular deposits are visible in cases with the eosinophilic type. In contrast, the surfaces appear smoother in the lymphocytic type. The disease can be diagnosed on the basis of the clinical appearance, with a supporting histological examination if necessary. In the differential diagnosis, neoplasms of the conjunctiva and cornea as well as inflammatory changes should be ruled out. The patients were examined and treated as inpatients between 2018 and 2020. The therapeutic plan included a combination of laser treatment with a diode laser, subconjunctival injections, local ointment therapy and systemic analgesic and anti-inflammatory treatment. Due to its immunological genesis, local treatment was based on cortisone. Dexamethasone was used for both subconjunctival injection, and eye ointment. All horses showed a clear improvement within 24 hours after the initiation of the therapy. Complete healing occurred between 7 and 14 days (on average, 9 days). Eight horses (9 eyes, 41 %) exhibited corneal involvement as a complication, ranging from punctiform erosions to ulcerations of about 8 mm in size. There was a relapse in two cases, and the therapy had to be repeated. In one horse, surgical excision of the altered tissue was also done. A regular check-up was carried out over a period of 10-36 months. No age dependency, breed or genetic predisposition was evident in the patients. This study has shown that it is necessary to observe, name and define new clinical entities in the eye to be able to carry out an adequate therapy. The multimodal therapy described appears to be very suitable for the treatment of KCV in horses. A critical examination of other patients is necessary to achieve better statistical evaluability due to a larger group and, if necessary, to obtain additional information on the aetiology.

Squamous cell carcinoma (SCC) is the most common tumor of the eye and adnexa in the horse and more frequently found in these days. Ultraviolet light exposure has increased during the last years, which is believed to be the reason for the high prevalence of ocular SCC. An older age, a lack of periocular pigment and a genetic predisposition are further factors for tumor growth. The appearance of SCC varies with its location. Limbal SCC is raised, cauliflower-like and light pink. When the tumor invades the corneal stroma, it may be mistaken for keratitis. A typical limbal or third eylid SCC is easily diagnosed with a usual eye exam. However, a histopathology is strongly recommended. The standard for tumor treatment is complete surgical removal of the abnormal tissue. Generally, excision alone is not sufficient and ancillary therapy is inevitable to avoid tumor recurrence. This study aimed to evaluate the potentials of mitomycin C (MMC), a antineoplastic antibiotic, in the management of ocular surface neoplasia. The records of 110 horses presented to our hospital with periocular SCC were analysed. 22 horses were excluded from the study because of advanced tumors, which required enucleation or euthanasia. 48 of the remaining 88 horses were treated with topical MMC (0,04 %, eye drops, eight times daily for one week), starting immediately after surgery. The second group included 40 horses, which had no further antineoplastic treatment after surgery. In this group (no MMC) eight horses showed tumor recurrence and needed removal of the globe as well as some of the adjacent tissues (20 %). Only two horses (5 %) needed enucleation in the first group (with MMC). Four more horses showed new tumor growth, but were successfully treated with the same protocol. Complications after surgery were rare, five horses developped some hypergranulation.

The steadily increasing number of patients with immune-mediated eye diseases in ophthalmological horse practice requires further development in the definition and therapy of these diseases. The aim of the present work is to describe an immune-mediated conjunctivitis with corneal involvement, which was observed in 28 horses with almost identical symptoms, and to define it as superior limbal keratoconjunctivitis (KCLS) based on human ophthalmology. Subsequently, a therapy method for this disease, which was initially declared therapy-resistant, should be developed. This was used as multimodal therapy, also with knowledge of established methods in human medicine. KCLS is an immune-mediated conjunctivitis that is manifested in the dorsal, limbal area and also affects the cornea in this area. In the patient's history, therapy-resistant conjunctivitis is always described, which shows no or only short-term improvement despite different medications. The clinical picture is characterized by a very painful eye with pronounced blepharospasm, edematous swelling of the eyelids and sero-mucous epiphora. In the ophthalmological examination, the first thing that stands out is the intensely reddened and swollen bulbar conjunctiva. The conjunctival and superficial scleral vessels are dilated. When examined with a slit lamp, filigree vessels of different lengths are visible in the cornea, starting from the dorsal limbus, which can be surrounded by wafer-thin or punctiform opacity. Angiogenesis in the entire dorsal limbus area (2-10 o'clock) is characteristic of this disease. In some cases, a narrowing of the pupil is also visible. After thorough ophthalmological examination, 28 horses (36 eyes) were diagnosed with KCLS. Multimodal therapy was performed on all eyes. The bulbar conjunctival vessels were initially closed using thermocoagulation. This was followed by laser treatment of the affected limbal areas at the transition from the sclera to the cornea. The filigree vessels in the cornea were closed in a semicircle using a neodymium-doped yttrium-aluminum-garnet laser through an indirect ophthalmoscope and a 20 D aspherical lens. In addition, the local therapy with the application of cortisone and antibiotic eye ointment with a 3 times daily frequency and the oral administration of non-steroidal anti-inflammatory drugs was continued. The clinical symptoms of the patients improved considerably 24 hours after the described therapy. The ophthalmological assessment of the affected eyes showed a significant improvement 5 days after treatment in combination with the described local and systemic therapy. The clinical symptoms were no longer visible and the vessels in the conjunctiva showed a physiological appearance. The neovascularization of the cornea could only be guessed at by bloodless vessel walls. 24 eyes (95 %) showed no further inflammation 12-34 months after multimodal treatment. Two eyes (5 %) again showed KCLS and have been treated repeatedly. In one of the two patients, the inflammation occurred 3 times week by week after treatment. After the third treatment, the eye has been free of inflammation for 12 months. The other horse developed new inflammation after 8 months. After repeated treatment, the eye is currently free of irritation and inflammation for 15 months. In our experience, the described multimodal therapy is an effective and minimally invasive procedure that is well suited for the treatment of KCLS in horses. This innovative combined treatment approach gives hope for improved therapeutic options for the long-term treatment of superior keratoconjunctivitis limbalis, from which particularly patients affected with long-term and,therapy-resistant" inflammation may benefit.

Several studies have dealt with the etiopathogenesis-, diagnostics as well as the conservative and surgical treatment methods of equine recurrent uveitis (ERU) with different outcomes.Because of potential side effects of applied medication, the risk of doping in the case of sport horses and the problem of future uveitis episodes, a traditional medical treatment is not always feasible.This circumstance requires other promising therapeutic approaches, such as the pars plana vitrectomy (PPV) and the insertion of a cyclosporine-A (CsA) drug delivery device.The literature provides varying perspectives on both of the aforementioned methods.Besides the successful PPV, the cyclosporine-A implant is proposed and applied with an increased frequency due to its nature of being an easier and financially lucrative surgical technique.Currently cyclosporine implants cannot be obtained and applied legally in Germany, therefore any usage is signified as a serious breach of the Medicines Law.According to the literature it appears that the majority of authors consider the PPV to be an effective treatment method only for leptospira positive tested horses, but nor for eyes testing negative for leptospiral antibodies.This retrospective study included 24 ERU patients of different age, gender and breeds that were initially examined by ophthalmological specialists beforehand and treated with suprachoroidal CsA implants.These horses having the CsAI still suffered from uveitis episodes, as the implant only masked inflammatory bouts resulting in a proceeding damage of intraocular structures.This circumstance required another therapeutic approach.Undiluted vitreous humor samples of all of the 24 horses were taken and were tested for specific antibodies against 9 different serovars of Leptospira interrogans by microscopic agglutination test (MAT).The ERU-diseased eyes of 4 horses were removed and in one horse an intrascleral eye prosthesis was inserted.Between 2013 and 2017 19/24 horses with ERU (79.2 %) with CsA implants, still having uveitis episodes, were treated via single port PPV.The outcome of the PPV and the postoperative course of the horses were followed up.The evaluation of efficacy of the PPV was deduced either directly by follow-up examinations (n = 8), photographic documentation and patient records or indirectly by questioning the referring owners (n =11).14/19 horses (73.7 %) were tested positive for intraocular leptospira antibodies and 5/19 horses (26.3 %) have been tested intraocular MAT negative.The absence of active uveitis was considered a success irrespective of the visual outcome of the surgical treated eyes.A total of 14/19 horses (73.7 %) remained relapse-free over a period of 5 to 63 months.10/14 horses (71.4 %) with leptospiral antibodies in the vitreous humor had no further uveitis relapses postoperatively, while only 1/5 horses (20 %) tested MAT negative continued to episodes of ERU.The comparison between numbers of horses with positive or negative leptospiral antibodies in vitreous humor in relation with or without recurrence of uveitis after PPV was not significantly different (P =1.0) using twosided Fisher's exact test.According to these findings, it is doubted to perform a PPV depending on the leptospiral antibody result.In none of the 24 horses the implant slowed down the progression of uveitic destruction and a therapeutic success could not be achieved at all.This study yields promising results that the PPV should be the selected treatment method instead of the CsA implant.