How can diabetes mellitus affect the eye? Cataracts Nearly all diabetic dogs will develop cataracts—50% of dogs within 12 months and 80% within 16 m
How can diabetes mellitus affect the eye?
Cataracts
Nearly all diabetic dogs will develop cataracts—50% of dogs within 12 months and 80% within 16 months. There is no apparent correlation between the control of the diabetes and the speed of the cataract development. Even well controlled diabetics can rapidly develop diabetic cataracts. THINK diabetes whenever you see sudden onset cataracts.
IT IS VITAL to start all eyes that have developed or are starting to develop diabetic cataracts onto topical anti-inflammatories. Start the medication even if there is no sign of LIU—lens induced uveitis.
Diabetics are especially prone to develop severe LIU. In most cases we will use topical cortisone e.g. Prednefrin Forte or Maxidex eye drops. In dogs with poorly controlled diabetes or if you suspect that the topical cortisone is affecting the diabetes, then we will use topical NSAIDs such as Voltaren eye drops. Oral NSAIDs can also be used if significant LIU—lens induced uveitis is present.
Consider EARLY Referral of diabetic cataracts. Unfortunately we regularly see diabetics that have had severe LIU causing retinal detachment, and or glaucoma meaning surgery is no longer an option.
Diabetic cataract surgery compared to age related cataracts have a higher overall success rate, particularly when done early.
Corneal Problems
Diabetic dogs have reduced corneal sensitivities, which is likely to be related to reduced trigeminal nerve function. This means that the reflex tearing will be reduced resulting in dry eye. Reduced corneal sensitivity means increased risk of corneal ulceration, and reduced trigeminal nerve function leads to reduced corneal healing. Consider a TEF—third eyelid flap and or a TT—temporary tarsorrhaphy for a diabetic with an ulcer.
Dry Eye
Diabetic dogs have lower Schirmer Tear Test readings compared to normal dogs. Always do a STT in all diabetic dogs.
Horners Syndrome
Diabetics are more likely to develop peripheral neuropathies. This can also affect the eye presenting as Horners Syndrome.
Hypertension
Diabetics have an increased risk of elevated blood pressure. This can result in retinal haemorrhage and detachment. Regular monitoring can detect this early. Treatment with Amlodipine generally controls the blood pressures.
