[Weak vision and blindness in the dog--a retrospective study]

Area of Science:

• Veterinary Ophthalmology
• Canine Vision Research

Background:

• Decreased vision and blindness are significant concerns in dogs.
• Cataracts are a common cause of visual impairment in canine populations.
• Accurate diagnosis of retinal function is essential for effective treatment and prognosis.

Purpose of the Study:

• To compare clinical-ophthalmological and electroretinographic findings in dogs with vision deficits.
• To determine the diagnostic utility of electroretinography versus standard ophthalmic examination.
• To investigate breed-specific patterns of retinal dysfunction.

Main Methods:

• Clinical-ophthalmological examinations were performed on 73 dogs of 21 breeds presenting with vision loss.
• Electroretinography (ERG) was utilized to assess retinal function, particularly when the fundus was not visualized.
• Vision tests and pupillary light reflex assessments were conducted.

Main Results:

• Cataracts were diagnosed in 51 out of 73 dogs.
• Electroretinography proved essential for evaluating retinal function in cases with obscured fundi.
• English cocker spaniels and miniature/toy poodles with cataracts exhibited significant electroretinographic retinal dysfunction, suggestive of progressive retinal atrophy.

Conclusions:

• Clinical-ophthalmological examination is sufficient for most vision loss diagnoses, with exceptions like sudden acquired retinal degeneration (SARD).
• Electroretinography is a vital tool for assessing retinal function, especially in cases of cataracts or non-visible fundi.
• Specific breeds, such as English cocker spaniels and poodles, may show breed- and age-related progressive retinal atrophy secondary to cataracts.