ABSTRACT:A four-year-old, male German Shepherd dog with severe pain in the left eye following a corneal perforation with a foreign body was examined. An ophthalmic examination revealed conjunctival hyperaemia and pancorneal dense oedema, preventing a diagnosis of deeper structures of the eye and lowered IOP. Vision testing was missing or impossible to detect. Ultrasonography showed a solid hyperechoic line protruding through the iris and lens into the vitreous and minor posterior lens displacement. The dog qualified for immediate surgical treatment. Intraoperative ophthalmic examination revealed a rupture of the anterior hyaloid membrane with vitreous herniation, posterior lens subluxation, lens capsule rupture and a torn iris. Partial iridectomy and intracapsular lens extraction (ICLE) was conducted. Slit-lamp biomicroscopy revealed iridodonesis and a gradual reduction of the corneal oedema, leading to complete transparency in the bottom two-thirds of the area on Day 12 after surgery. Direct and consensual PLR was sluggish and the dazzle reflex was positive. An electroretinographic examination confirmed normal activity of the retina.

Electroretinography (ERG) in the form of full-field, flash ERG is the most commonly used technique in veterinary ophthalmology for diagnosing the functioning of the outer retina. Under light stimulation spatially distributed different cell types within the retina produce time-varying electric responses. These are recorded in the form of ERG traces consisting of a series of positive and negative wavelets. The possibility of selective stimulation of individual types of retinal cells and the analysis of constituent components of ERGs are the basis for determining the source of abnormalities and diagnosis of various types of dysfunction. In many cases, the ERG allows diagnosis of hereditary retinal disorders in dogs before the appearance of behavioural and ophthalmoscopic symptoms. This review is an introduction to the electrophysiology of vision, intended for small animal practitioners, and aimed at presenting the benefits of ERG for early ophthalmic diagnostics in dogs.Keywords: ERG; ophthalmology; PRA; retina

An eight-year-old gelding, Wielkopolski Horse was presented with a pink tumour, which filled the entire palpebral fissure of the left eye. Ultrasonography revealed it to be well-demarcated from the cornea mass, which covered its entire surface. Due to the extensive size of the lesion and the lack of owner's consent to postoperative treatment, it was decided to perform enucleation. A histopathological examination revealed corneal squamous cell carcinoma (CSCC). The primary cause of the tumour has not been established. Immunohistochemistry was negative for p16 immunoreactivity which is typical for the E7 oncoprotein in PV infection, and is suspected of involvement in the aetiopathogenesis of ocular squamous cell carcinoma (OSCC).

Individual types of retinal dysplasia -folds, geographic and detached, have different impacts on vision ability. The purpose of this study was to undertake a qualitative and comparative evaluation of retinal activity in the individual types of the retinal dysplasia -folds, geographic and detached. Dogs (n = 24) with an ophthalmoscopic diagnosis of retinal dysplasia (rd) underwent vision testing, ophthalmologic examination and electroretinography. A three-degree scale (mild, moderate and severe) was used to describe the severity of ophthalmoscopic lesions in the rd folds and rd geographic forms. Our findings indicate that retinal folds of mild and moderate severity, and the mild geographic type of the rd, have similar effects on ERG responses, while severe retinal folds give lower ERG responses than moderately advanced geographical rd. This study confirms that electroretinography may generate a more comprehensive view of an altered retinal activity in the course of rd, which is helpful in making decisions on qualifying or excluding a given individual from the breeding program.

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