Introduction
- The nictitating membrane can be used as a flap to protect and support the weakened cornea and to assist corneal healing:
- Warming cornea promotes higher cellular metabolic rates.
- Lymphoid follicles on bulbar nictitans provide inflammatory cells to cornea.
- Decreases trauma to cornea from normal lid movement.
- Decreases evaporation of tears.
- Scarification of bulbar surface can provide serum/inflammatory cells, fibroblasts and blood.
Uses
- Protection of superficial corneal ulcers
. - Temporary exposure keratitis .
- After corneal repairs (rarely needed) .
- Acute keratoconjunctivitis sicca (rarely used).
- Corneal vesicles associated with corneal edema .
Advantages
- Simple to perform.
- Gives good protection to cornea.
- Topical liquid medication and ointments can still be administered.
Disadvantages
- Cornea cannot be examined while flap is in place (bandage contact lens better from this perspective).
Requirements
Materials required
Minimum equipment
- Ophthalmic kit .
Minimum consumables
- 2/0 to 3/0 non-absorbable suture material, eg silk .
Other requirements
- Elizabethan-type collar
.
Preparation
- Minimal.
Sequelae
Reasons for treatment failure
- Corneal irritation +/- ulceration: due to contact between cornea and sutures .
- Sutures tearing out.
