The eyes in leprosy, iritis (uveitis)

You will need a system of priorities when you approach a leprosy patient. The most important function you need to preserve is his sight. If he has also lost the feeling in his fingertips, blindness will separate him from his environment almost completely.

Leprosy causes: (1) Paralysis of his facial nerve, so that he cannot close his eye (lagophthalmos, 30.3). (2) Loss of sensation in the ophthalmic division of his fifth cranial nerve, which makes his cornea anaesthetic. (3) An acute iritis (uncommon), which is usually associated with a Type Two reaction. (4) A chronic iritis (common) causing atrophy of his dilator pupillae and a small unreactive pupil (see also Section 24.5).

Iritis is common in lepromatous leprosy. It usually comes on so slowly that he may not notice that there is anything wrong with his eyes, until they are severely damaged, and he starts to lose his sight from synechiae, cataracts, or secondary glaucoma (rare). An acute uveitis occurs mainly in patients who have a Type Two lepra reaction, and is less common if they are on clofazimine.

To detect uveitis, use a corneal loupe, and preferably a slit lamp microscope. Grossly, you may see mild ciliary hyperaemia on his conjunctiva next to the limbus. This is a good indication of activity, and you can always see it with a good light; but be careful to distinguish it from conjunctivitis. If you press his globe he may complain of pain. With a slit lamp, the earliest signs are keratic precipitates (KP) on the back of his cornea, a flare, and cells floating in his anterior chamber; these are also the last signs to disappear. If you are in any doubt, and you don't have a slit lamp, dilate his pupils. Any irregularity due to synechiae will then be diagnostic, but it will not tell you if his iridocyclitis is active. If dilatation relieves his pain it probably is active.

THE EYES [s8]IN LEPROSY ROUTINE EXAMINATION. Examine the eyes of all leprosy patients regularly to detect. (1) Lagophthalmos and corneal exposure. (2) Chronic iritis, which may cause secondary glaucoma and blindness. See also Sections 24.1 and 24.5.

(1) Measure the patient's visual acuity. (2) Assess his normal eyelid closure as in sleep (not his forced eyelid closure). If his lids don't touch he has lagophthalmos. (4) Dilate his pupil with a short-acting dilator to see if it is irregular (a sign of iritis). (5) Stain his corneae with fluorescein to look for ulcers due either to lagophthalmos or an ananaesthetic cornea.

IRITIS [s7]IN LEPROSY TREATMENT. Dilate his eyes with 1% atropine eye ointment, or atropine drops, hourly for three hours, or until they are dilated, and then once daily. Give him hydrocortisone or cortisone eye drops or ointment 3 or 4 times daily. If synechiae persist, continue atropine twice daily. If redness or pain persist, or if his corneae are cloudy, he may need steroids by subconjunctival injection, or rarely by mouth. If you give them, he must be taking his leprosy drugs at the same time. He should respond well, if you treat him early. If he has a chronic Type Two reaction (ENL), he may need atropine once weekly and steroid ointment daily for many months.

If his intraocular tension is raised (secondary glaucoma, 24.5), also give him acetazolamide 250 mg 6-hourly, until the inflamation is under control. Use phenylephrine eye drops 10% 3 times daily to lower his intraocular pressure, instead of atropine. Refer him if you can.

CAUTION ! (1) If his eyes are not much better, and he still has pain after 7 days, refer him[md]urgent treatment may be necessary to save his sight. (2) Make sure that his eyes are examined every week and his pupils are regularly dilated.

If the disease has progressed far enough for ''ring synechiae' to be present, and his intraocular pressure is raised, refer him for a broad iridectomy to save his sight. Ideally, this should not be done until his eye is quiet and white, but this is usually impossible, because he will be blind before it happens.

If he develops a secondary cataract, this will need surgery, but it should not be done at the same time as the iridectomy. Always delay cataract extraction until you are absolutely sure an eye is quiet. This may take years! If his cataract is extracted too soon, while his uveitis is still active, he may become blind.