Fundus photography with a smartphone in indirect ophthalmoscopy in dogs and cats.

OBJECTIVE: To introduce a simple method for fundus photography of dogs and cats using a smartphone and indirect ophthalmoscopy lenses. METHODS: Fundus photographs of dogs and cats with transparent ocular media were obtained with 15D, 20D, 28D, and 40D indirect lenses and an iPhone-6, in a dark room and after pharmacologic pupil dilation. The photographs were recorded as still images using a video application and a video-to-still image application. Two types of neutral density (ND) filters were used as required for reduction of the torch illumination power of the iPhone. RESULTS: The images obtained in this study were upside-down as a result of the optics used. A 180-degree rotation was used to show their natural anatomical orientation. The image field of view varied with the diopter strength of the indirect lens used. The 40-diopter lens offered the widest field. CONCLUSION: Still images obtained with a smartphone, and indirect lenses may be useful for client communication and teaching in small animal ophthalmology.

Conjunctival expression of the P2Y2 receptor and the effects of 3% diquafosol ophthalmic solution in dogs.

Conjunctival epithelial and goblet cell P2Y2 nucleotide receptors regulate ion transport and secretory function. Diquafosol is a P2Y2 purinergic receptor agonist that stimulates secretion of aqueous tear components from conjunctival epithelial cells and secretion of mucin from conjunctival goblet cells. In humans suffering from keratoconjunctivitis sicca (dry eye), topical administration of diquafosol improves corneal epithelial integrity and stabilises the tear film. The aim of the present study was to investigate P2Y2 receptor expression and to determine the effect of topical administration of diquafosol on mucin and aqueous tear production in dogs. Canine conjunctival P2Y2 receptor expression was evaluated by Western blotting and immunohistochemical analysis. The effect of diquafosol on mucin secretion was evaluated by examining mucin-5 subtype AC (MUC5AC) concentration in tears. The effect of diquafosol on aqueous secretions was evaluated by performing the Schirmer tear test (STT) and phenol red thread test. Expression of the P2Y2 receptor was confirmed in canine bulbar and palpebral conjunctivae and receptors were identified at the conjunctival epithelial and goblet cell surface. Tear MUC5AC concentration significantly increased after administration of 3% diquafosol ophthalmic solution, although neither STT nor phenol red thread test values showed any significant change after diquafosol instillation. Topical ocular administration of 3% diquafosol might improve corneal epithelial disorders in dogs through stabilisation of the tear film, by virtue of an increase in MUC5AC secretion.

Efficacy of the use of a colorimetric pupil light reflex device in the diagnosis of fundus disease or optic pathway disease in dogs.

The aim of this study was to determine the efficacy of a colorimetric pupil light reflex (PLR) device (Melan-100(®), U.S.A.) in dogs with sudden acquired retinal degeneration syndrome (SARDS; 16 cases), progressive retinal atrophy (PRA; 10 cases) and optic pathway disease (6 cases). The colorimetric device detected PLR abnormality in 32, 16 and 9 eyes with SARDS, PRA and optic pathway disease, respectively, whereas white light detected PLR abnormality in 18, 11 and 9 eyes with SARDS, PRA and optic pathway disease, respectively. SARDS dogs displayed miosis, while optic pathway disease dogs displayed mydriasis in a blue light examination. Thus, colorimetric PLR may be a useful method for determining whether electroretinography (ERG) or magnetic resonance imaging (MRI) should be performed for dogs with acute blindness.