January 2024 41 One of the classic signs to alert the examiner of a LIU is the presence of melanin pigment dispersion on the anterior lens capsule. [Fig 11 and 12]. Unfortunately, if the LIU is not managed immediately, it may lead to hyphaema, phthisis of the globe [shrinking in size], secondary glaucoma, vitreal degeneration, hyalitis, lens subluxation/luxation, retinal degeneration or detachment and, subsequently, irreversible loss of vision and more importantly, the window of opportunity to consider cataract surgery can also be lost. How do we manage such cases: All diabetic dogs will develop cataracts, and the LIU is a common feature that often goes undiagnosed. Because of its destructive action, one must be able to look for the subtle signs and manage the uveitis. Ideally, the client should consider cataract surgery as the only way to salvage vision in the eyes. If cataract removal surgery is not a possibility, dogs usually adapt well to blindness. Their eyes should be monitored throughout their lives for signs of uveitis, secondary glaucoma, retinal detachment and lens subluxation or luxation. General ocular health also needs to be monitored. If the cataract is mature, the surgery can be performed well before the dog is stabilized on insulin, provided the patient is otherwise stable and medically well. This would be the owner’s decision. Far too often, too much time is spent trying to“stabilize”the patient and the LIU occurs, resulting in the eye being lost. If surgery is not an option for the client, the veterinarian needs to explain the concept of LIU and proceed to explain that one needs to be proactive and use prophylactic medications to assist in either reducing the current active LIU or the managing the subclinical case. Although topical corticosteroid drops work very well to suppress uveitis, they can potentially be absorbed from the conjunctiva, globe and nasolacrimal duct and have been shown to possibly affect the blood glucose status in the long term. Based on this, it is best to consider using a topical non-steroidal anti-inflammatory drug. If the LIU is mild, these drops may be applied once daily, 2-3 times per week and often this low dose seems to stabilize the uveitis. More severe cases will require daily topical medication or even oral medication may be required. It is strongly advised that these patients should be examined regularly by a veterinary ophthalmologist to monitor the severity of the uveitis, as well as pressure changes. Should the LIU lead to severe ocular pain or even glaucoma, the owner needs to consider enucleation. Concluding points: • All diabetic dogs will develop cataracts. In some cases, this is within days, and with others, a little later. • Every patient with diabetic cataracts [or all cataracts for that matter] should be examined by a veterinary ophthalmologist [using slitlamp biomicroscopy] to assess the presence of uveitis and to measure intraocular pressures. • Diabetic cataracts cause blindness and the only way to maintain vision is by cataract surgery [phacoemulsification]. The surgical success rate decreases and the complication rate increases with maturity of the cataract and developing LIU, so early referral is crucial. • There is a short window of opportunity to consider surgery. Frequently this is lost and the globe is destroyed. If surgery is delayed and lens-induced uveitis develops, the risk of complications is higher, and the prognosis for vision after cataract surgery is guarded to poor. Delayed surgery and preoperative complications can make the procedure challenging or even impossible. • Lens-induced uveitis can be subtle. Medication needs to be initiated in all cases where symptoms are noted. v Figure 12 Regulars I Ophthalmology Column
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