ARTICLES “IOP measurement is an important diagnostic aid and should be monitored throughout the whole period of treatment.” Fibrinous exudate may cause adherence between the iris and lens (posterior synaechia), resulting in aqueous be- ing trapped behind the iris and subsequently a gradual increase in intraocular pressure. Inflammatory cells and fibrin blocking the iridocorneal angle may also cause secondary glaucoma. Inflammation in the posterior uvea, the choroid, causes less dramatic clinical signs, but the eye appears red with hyperaemia of episcleral blood vessels. Swelling of the choroid may cause fluid to accumulate behind the retina, resulting in retinal detachment and blindness. The retina may also be affected by concurrent inflammation, chorioretinitis. A thorough work-up is recommended in all animals with uveitis, as uveitis can be associated with systemic diseases. The choice of treatment depends on primary diagnosis and severity of clinical signs. Treatment includes anti-in- flammatory treatment/treatment of pain, mydriatics, plus antibiotics when necessary. Occasional secondary ocular hypertension must be diagnosed and adequate drugs instilled. Long-term treatment is often required in uveitis. IOP measurement is an important diagnostic aid and should be monitored throughout the whole period of treatment. Treatment should not be stopped before IOP is back to normal. HIGH INTRAOCULAR PRESSURE – OCULAR HYPER- TENSION - GLAUCOMA The most common cause of ocular hypertension is obstruc- tion of outflow. Causes include abnormal development of the iridocorneal angle, resulting in insufficient drainage (primary glaucoma). This is a relatively common and breed- related disease that affects both eyes. Clinical signs develop in middle aged dogs, but not necessarily in both eyes simultaneously. Secondary glaucoma develops as a sequel to other ocular disease, either because of intraocular tu- mours, posterior synaechia, or by obstruction of the irido- corneal angle and/or the ciliary cleft by inflammatory cells. Early clinical signs of glaucoma include serous discharge, blepharospasm, hyperaemia of conjunctival, episcleral and scleral vessels, slow or absent pupillary light reflexes and mydriasis. Fundus is normal in early stages, except from the optic disc that appears pale, later cupped (pressed back- wards). Clinical signs in more advanced stages include pain, mydriasis, corneal oedema, conjunctival, episcleral and scleral vessel congestion, buphthalmia, retinal degeneration and blindness. IOP measurement is an essential part of work-up and treatment of all ocular conditions • IOP > 30 mmHg over some days damages the optic nerve and retina • IOP > 40 mmHg is painful and causes enlargement of the globe (buphthalmia) • IOP > 40-50 mmHg leads to paralysis of the sphincter The principles for treatment of primary glaucoma have been to reduce the intraocular pressure, either medically or by surgery. Newer research may indicate that other agents, i.e. neuroprotective agents, may also be helpful in maintaining vision in affected dogs. Nevertheless, even if adequately treated, glaucoma is a malignant disease with a guarded prognosis. In breed-related primary glaucoma close follow-up and treatment of the fellow, normotensive eye is indicated. 9
