A symblepharon is a partial or complete adhesion of the palpebra conjunctiva (that coats the inside of the eyelid) to the bulbar conjunctiva of the eyeball, (that covers the outside surface of the eye). It results either from disease (conjunctival sequelae of trachoma) or trauma.
Causes of Symblepharon
Cicatricial pemphigoid and,in severe cases, rosacea may cause symblepharon. It is rarely congenital.
Symblepharon may also occur as a complication of various ocular diseases such as:
- dry eye syndrome,
- Stevens-Johnson syndrome,
- chemical injury,
- erythema multiforme,
- pemphigus bullosa
- or as a complication of chemical burn.
Any conjunctival infections complicated with conjunctival scarring may cause symblepharon;
- chlamydial conjunctivitis,
- vernal, atopic, bacterial conjunctivitis, and
- epidemic keratoconjunctivitis.
Risks of Symblepharon
Symblepharon can result in ocular motility restrictions, meaning that there is difficulty in controlling the muscles and movements of the eye. It can also result in double vision (diplopia), incomplete eyelid closure, and entropion. Entropion is a medical condition in which the eyelid (usually the lower lid) folds inward. Entropion causes great discomfort, as the eyelashes continuously rub against the cornea causing irritation. This is turn causes secondary negative effects on the ocular surface.
Treatments of Symblepharon
Different approaches have been used to surgically manage chronic symblepharon. and its treatment is symblepharectomy.
Various materials have been evaluated as a mechanical barrier to keep potentially adhesive surfaces apart after removal of the symblepharon, including conjunctival autograft, where a healthy part of the patient’s conjunctiva is removed and grafted into the problematic area. Other materials include mucous membrane grafts from the mouth. The problem is the difficulty in harvesting the material to be grafted, the limited availability of materials, and potential complications at the donor site.
Amniotic membrane transplantation (AMT) has been used for different eye disorders such as corneal ulcers and macular degeneration, and is known to be highly effective in both promoting re-epithelialization and suppressing inflammation. Amniotic membrane provides a new basement membrane that helps in the migration of epithelial cells, reinforces adhesion of basal epithelial cells, promotes epithelial differentiation and prevents epithelial breakdown. It also inhibits fibroblast proliferation and prevents the subconjunctival fibrosis that causes scarring, and hence the recurrence of symblepharon (a common complication). In addition, graft rejection is unlikely.
Prevention of Symblepharon
Symblepharon after acute conjunctival injury can be prevented by separating the raw surfaces for one to two weeks, until re-epithelialization takes place. Doctors sometimes use a soft contact lens and a conjunctival ring without a corneal center, or line the eyelid and palpebral conjunctiva with plastic. This often eliminates the need for mucous membrane grafts. Symblepharon can interfere with intraocular surgery and disrupt cataract incisions unless they are divided and separated at the time of surgery.
Studies regarding amniotic membrane and symblepharon
While it is important to remove adhesions, chances of recurrence are great without adjuvant therapy. Amniotic membrane has been studied in preventing recurrence. In one study of 10 eyes of 10 patients examining the efficacy, safety, and outcome of symblepharon excision with amniotic membrane transplantation, amniotic membrane transplantation was found to be effective in ocular surface reconstruction. After an operation with standard technique, the patients were followed for 6 months. Every eye exhibited a healthy corneal surface and conjunctival growth without the regrowth of symblepharon or other epithelial effects. In 60% of cases, there was visual improvement. Eighty per cent patients showed symptomatic relief. The amniotic membrane appeared to decrease inflammation.
Amniotic membrane transplantation might also be appropriate for treating children. Amniotic membrane transplantation with symblepharon lysis is effective for ocular surface reconstruction in the management of epidermolysis bullosa and other conditions that cause corneal scarring and symblepharon in children. In this small series, children with epidermolysis bullosa fared better and the effects of surgery lasted longer compared with patients with other causes of symblepharon and massive pannus.