Entropion is a inward rolling of the eyelid. It is quite a common congenital defect in sheep and goats, most commonly affecting the lower eyelid. The hairs of the eyelid irritate the corneal surface, causing the eye to run and for staining to appear down the cheek. This is often the first sign which is noted by the keeper.
Luckily, there is a good response to treatment. There are a number of different options for correction:
- Injection into rolled eyelid. Most commonly, long-acting penicillin is injected, although theoretically any fluid would work - the reason this method works is the physical presence of the small bolus, which unrolls the eyelid, then the irritant factor, which gives the tissue greater rigidity. Sometimes this procedure requires repeating 1-2 weeks later.
- Surgical correction. A small transversely oriented piece of tissue is removed from the lower eyelid, approximately half a centimetre from the edge of the lid. As this wound heals, the contraction of the epithelial tissue leads to correction of the entropion. Overcorrection can occur in some cases.
- Application of Michel Suture Clip. To affect eversion of the rolled lid. Some authors describe using the clips vertically to pull the lid down; some authors describe using the clip horizontally to produce a vertical fold which gives the eyelid greater rigidity in the horizontal plane.