A survey of ocular ultrasound abnormalities in horse: 145 cases

Ultrasonographic and histopathologic features associated with common ocular diseases in donkeys (Equus asinus)

There is a lack of reports describing ultrasonographic and histopathologic features of ocular diseases in donkeys. The present study aimed to document ultrasonographic and histopathologic changes associated with common ocular diseases in donkeys. The study included 45 donkeys (64 eyes) with ocular diseases that had reached the end of their working lives and requested to be used for educational and research purposes. Complete clinical, ophthalmic, ultrasonographic, gross pathologic and histopathologic examinations were included. Ocular abnormalities were documented, tabulated, and analyzed. Seventy-five ocular abnormalities were diagnosed with multiple involvements within the same eye including anterior uveitis (n = 13; 22.8%), cataract (n = 57; 76%), retinal detachment (n = 3; 4%), lens and phthisis bulbi (n = 2; 2.6%). Descriptive ultrasonographic findings of ocular abnormalities were included. Gross pathologic and histopathology findings confirmed the ultrasonography findings. Ultrasonography provided a clinically useful tool offering insight into detailed intraocular structures especially with opacification of the dioptric structures of the eye.

Noninvasive 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.

Ultrasound, Dacryocystorhinography and Morphological Examination of Normal Eye and Lacrimal Apparatus of the Donkey (Equus asinus)

The study investigated normal macromorphological and ultrasonographic features of the eye and lacrimal gland, as well as normal dacryocystorhinography of the donkey (Equus asinus) in Egypt. A total of 36 donkeys of different ages, weights, and sexes were included in the study: 21 live animals for ultrasonography and dacryocystorhinography, and 15 cadaver skulls for morphological anatomy of the lacrimal apparatus. The ultrasound biometric values of the eye were 33.7 ± 1.7 mm for axial globe length (AGL), 39.8 ± 2.1 mm for globe diameter (GD), 10.8 ± 0.7 mm for lens thickness (LT), 3.2 ± 0.7 mm for anterior chamber depth (ACD), and 19.3 ± 1.6 mm for vitreous chamber depth (VCD). The lacrimal gland was recognized as a hypoechogenic structure with an anechoic core, located at the dorsolateral aspect of the orbit, and ovoid in shape. The mean NLD length was 193.0 ± 9.8 mm by radiography and 206.0 ± 20.4 mm by gross assessment. One NL orifice (NLO) was noticed on each side, with a diameter of 3.0 ± 0.1 mm and located 12.1 ± 2.1 mm from the dorsal commissure of the nostril. These results may act as the baseline for proper management of conditions of the eye and lacrimal apparatus in the donkey in the future.

Atypical free-floating iridociliary pigmented epithelial cysts and secondary glaucoma in a caiman (Caiman latirostris)

We describe a case of chronic ocular trauma that resulted in fixed and free-floating, pigmented epithelial iridociliary cysts, inflammation, and secondary glaucoma in a caiman (Caiman latirostris). A 20- to 25-year-old male caiman was presented with phthisis bulbi in the right eye, and congested episcleral vessels, corneal leukoma, disorganized anterior chamber, multifocal anterior synechia, and elevated intraocular pressure in the left eye. Ocular ultrasound of the left eye revealed round structures dispersed in the anterior and posterior chambers and vitreous cavity. Bilateral enucleation was performed, and gross pathology of the left eye revealed multiple pigmented cysts attached to the iris and posterior corneal surface causing marked distortion of the anterior uvea, and free-floating in the vitreous cavity. Histopathology demonstrated heavily pigmented cystic structures of iridociliary epithelium origin carpeting the anterior segment surfaces and causing obstruction of the iridocorneal angles, leading to secondary glaucoma. To the authors' knowledge, this is the first report of iridociliary cysts in wildlife species.

Use of autologous fascia lata graft to repair a complex corneal ulcer in a mare

Background

Application of an autogenous fascia lata graft in the treatment of keratomalacia in the horse has not been reported. The present case describes the use of an autologous fascia lata graft to surgically treat a complicated corneal ulcer in a horse.

Case presentation

A 12-year-old Arabian mare was admitted to Sharjah Equine Hospital with a history of right eye ulcerative keratitis of unknown duration. Following a week of aggressive medical treatment, the condition deteriorated and a keratectomy and pedicle conjunctival graft were performed. A week later, the conjunctival graft partially dehisced and the ulcer continued to degrade.

In attempting to preserve the integrity of the globe a second grafting procedure was performed when a segment of fascia lata harvested from the ipsilateral hind leg was grafted onto the corneal lesion.

Response to surgery was positive and the mare was discharged from the hospital on Day 31 post diagnosis (17 days after the second surgery) with a comfortable eye.

Follow-up12 months later revealed a comfortable but only partially visual eye due to corneal scarring.

Conclusion

Although the graft actually failed from the point of view of tissue integration, fascia lata appears to be a readily available, effective and affordable autografting material and we believe this technique has potential for short term physical and structural support of severe malacic or other complex corneal ulcers.