Evaluation of aqueous tear production in dogs after general anaesthesia with medetomidine-propofol-carprofen-halothane.

The influence of an anaesthetic protocol, which included medetomidine, propofol, carprofen and halothane on tear production in the dog. There are no previous studies on the effects of this combination on tear production in dogs or in any other species. The present study included 39 dogs, which underwent non-ophthalmic surgery in our clinic. Preanaesthetically, all dogs had normal tear production (18.62±3.65 mm/minute) as this was recorded with Schirmer tear test I (STT I) and the ophthalmologic examination did not reveal anything abnormal. Tear production readings were recorded before the administration of premedication, at the end of anaesthesia, one hour and two hours postanaesthesia. No reverse agent was administrated. At the end of anaesthesia (right eye (oculus dexter, OD) P<0.0005, left eye (oculus sinister, OS) P<0.0005), as well as one hour postanaesthesia (OD P=0.020, OS P=0.001) there was a statistically significant reduction in tear production, which returned to normal values two hours postanaesthesia, regardless of the duration of the operation. This anaesthetic combination resulted in a decrease in tear production and, therefore, the use of tear substitute treatment in dogs undergoing anaesthesia with this protocol (combination) from the time the sedative is given until at least two hours after the end of anaesthesia is highly recommended.

The precorneal tear film in horses: its importance and disorders.

The precorneal tear film (PTF) is of critical importance in the physiologic and pathologic findings of the cornea. Clinicians should recall that quantitative and qualitative disorders of the PTF can be a cause of corneal diseases as well as a clinical sign of ocular surface diseases. It is also important to consider that some systemic and topical treatments may affect the PTF volume and composition. Not all interactions are known at this time. There is a continued need for basic research into PTF components in healthy and diseased equine eyes, because much remains unknown. Until additional basic information about the biochemical composition and pH of the PTF as well as the interactions between equine corneal pathogens and specific PTF deficits becomes available, it will not be possible to define the cause and effect relations precisely between the various ocular surface diseases and deficiencies,excesses, and imbalances of PTF components. It is quite possible that a number of equine corneal diseases may be manifestations of qualitative PTF disorders.

Xerostomia, xerophthalmia, and plasmacytic infiltrates of the salivary glands (Sjögren's-like syndrome) in a cat.

A 2.5-year-old domestic shorthair cat was evaluated because of dysphagia and weight loss of 4 weeks' duration. MIld blepharospasm and conjunctival hyperemia were evident in both eyes, oral mucous membranes were tacky on palpation, and salivary glands were enlarged. Results of a Schirmer tear test were 0 mm/min for both eyes. Administration of atropine did not cause salivation or caused secretion fo thick rope-like saliva. Examination of biopsy specimens of salivary glands revealed a plasmacytic infiltrate. Sjögren's syndrome (SS) was diagnosed. Oral administration of prednisone was instituted but was discontinued after a minimal positive response was evident 6 weeks after initiation of treatment. Palliative treatment with a 6% solution of pilocarpine 4 to 5 times/d, cyclosporine, hylan A, and neomycin-polymyxin-bacitracin ophthalmic ointment resulted in clinical improvement in the cat. Although reported rarely in animals, SS may be more common than currently is recognized. Most treatment regimens for SS are aimed at alleviating clinical signs.

Evaluation of aqueous tear production in dogs following general anesthesia.

Pre- and postanesthetic Schirmer tear test (STT) values were measured in 46 dogs. All subjects had normal preanesthetic STT values (18.3 +/- 2.8 mm per min in the left eye [OS] and 18.3 +/- 3.0 mm per min in the right eye [OD]). Significant differences were found between pre- and postanesthetic STT values. Significant decreases in tear production were evident for up to 24 hours following the anesthetic event. Subject age did not significantly influence the results. Duration of anesthesia significantly affected the rate of return to preanesthetic STT values, with anesthetic events greater than two hours in duration having a prolonged effect as compared to anesthetic events less than two hours in duration. Anticholinergic administration prior to or during anesthesia further lowered postanesthetic STT values.

[Corneal pathology in the cat and dog]. / La pathologie cornéenne du chat et du chien.

Corneal diseases in the Cat and the Dog are of great variety and present similitudes with human corneal disorders, as demonstrated by the present report which discusses dystrophies, degenerations and inflammations of the cornea successively. Deep endothelial dystrophies are rare, poorly understood, and related to certain breeds; lipid dystrophies are frequent and either primary, occurring in some breeds only, or secondary to hyperlipemia; calcareous dystrophies are breed-related affections. Primary corneal degeneration has been described in the cat only and is a very rare affection. Keratitis is by far the commonest corneal lesion reported, and may be of herpes virus origin in the Cat and due to adenovirus in the Dog. Dry keratitis as in humans has also been observed. Two types of keratitis of allergic origin are described which are closely related to two breeds of dog: Alsatians and the long-haired dachshund. Recurrent corneal erosions, poorly recognized in veterinary medicine, are now described; their etiology and histological appearances are comparable with those reported in humans. These findings emphasize the interest of using animal models for human pathology investigations.