Conjunctival Flaps

Persistent Corneal Epithelial Defect

Persistent, noninfected corneal ulcerations that do not respond to lubrication, patching, bandage contact lens, moist chamber, or temporary tarsorrhaphy are the most common indications for a conjunctival flap. Such ulceration may result from denervation of the cornea and neurotrophic keratitis, paralysis of cranial nerve VII leading to exposure keratitis, corneal anesthesia following herpes zoster ophthalmicus, neurotrophic ulceration associated with chronic herpes simplex keratitis, and a damaged ocular surface from severe chemical injury resulting in chronic nonhealing epithelial defects. Independent of the cause of the nonhealing epithelial defect, conjunctival flaps protect the cornea during the most critical period and, in addition, provide metabolic support, allowing the cornea to regain its integrity.

It is important to note that active disease may persist despite antiviral and surgical therapy in some patients with herpes simplex corneal ulceration. In fact, recurrent herpes simplex infection in a conjunctival flap has been described.

Bullous keratopathy in patients with little or no useful visual potential is also an indication for conjunctival flap surgery, which provides an intact surface, alleviating discomfort and pain. ^{, ,}

Unresponsive Ulcerative Microbial Keratitis

Acute microbial keratitis is rarely an indication for the performance of a conjunctival flap. However, it may be useful in either bacterial or mycotic keratitis in which damage to the epithelial basement membrane and underlying stroma prevents surface healing. In addition, conjunctival flaps may be used in the management of unresponsive peripheral corneal fungal ulcers and Acanthamoeba keratitis. ^, A case of refractory Pseudomonas keratitis successfully managed using this procedure as adjunct therapy has been reported.

Conjunctival flaps have been used as an effective surgical therapy for peripheral microbial abscesses in corneal grafts when conventional medical treatment failed. Clear corneal wound infection post phacoemulsification may also benefit from a conjunctival flap as adjunct treatment.

Corneal Thinning and Perforation

In cases of descemetocele formation in eyes with poor visual potential, flaps may be used with good results. ^, However, thin conjunctival flaps are not appropriate for active suppurative processes with impending corneal perforations or perforated corneas in eyes with good visual potential, because only a very thin layer of conjunctiva covers the ulcer. In these cases a cystic flap may result, with loss of the anterior chamber.

For impending perforations or perforated corneas when donor corneal material is not available or transplantation is not suitable, a thick pedunculated conjunctival flap with adherent Tenon capsule secured in place by sutures may be used to provide stronger mechanical support for the cornea. This technique provides closure of the perforation and prevents leaking from the anterior chamber. A review of 50 consecutive cases demonstrated no bleb formation at the site of the conjunctival flap.

Inflammatory corneal thinning of a Boston keratoprosthesis type 1 (KPro) donor graft has been treated with a conjunctival flap. Tarsal conjunctival flaps have been used to cover the type 1 KPro device in patients with autoimmune diseases, where the donor button can potentially suffer sterile keratolysis. The procedure was performed in two steps, in eyes with high risk of poor retention or in cases of melting and device extrusion. A limitation in using conjunctival flaps in KPro patients may be the compromised conjunctiva and ocular surface secondary to the primary disease or multiple previous surgeries. Careful evaluation of the conjunctiva before indication of surgery is therefore recommended.

Corneal Limbal Disease

Ectatic thinning of the cornea near the limbus, wound fistulae, and pterygium surgery are other indications of conjunctival flaps. In these conditions, flaps may be used in conjunction with lamellar corneal or scleral patch grafts when significant thinning is present.

Conjunctival flaps in pterygium surgery provide lower recurrence rates when compared with bare sclera technique or amniotic membrane transplants. This is a safe technique using a pedicle graft, although it is not used as frequently as free conjunctival autografts.

It is important to remember that in immune-related diseases, such as Mooren ulcer, conjunctival flaps to prevent corneal perforation are not recommended. Recently, two cases inappropriately treated with conjunctival flaps were reported, and both patients presented rapid deterioration of the ulcer. The conjunctiva is rich in blood vessels, immune mediators, and proteases. For this reason, bringing the conjunctiva over the ulcer will increase inflammation and lead to ulcer progression. Instead, these cases tend to respond well to conjunctival resection.

Scleral Necrosis

A conjunctival flap in conjunction with a donor scleral patch graft provides an alternative to the challenging management of necrotizing scleritis. ^, Tectonic support and globe integrity can be achieved in cases in which severe scleral melting cannot be controlled with systemic treatment alone.

Scleromalacia secondary to pterygium excision with bare sclera and mitomycin C application can also be treated successfully with conjunctival flap surgery. Calcified scleromalacia caused by compromised vascular supply in periocular surgery has also been treated with a conjunctival flap.

Glaucoma Surgery Complications

Pedicle flaps can also be used to repair leaking filtering blebs and exposed glaucoma drainage implant devices. Conjunctival pedicle flaps have been used for surgical bleb revision in cases of leaking blebs, with high healing rates.

Surface Preparation for a Cosmetic Scleral Shell

Patients with phthisis bulbi, microphthalmia with no useful vision, or a blind disfigured eye may benefit from the use of a cosmetic scleral shell. When the underlying cornea is sensitive, the prosthetic shell may cause significant irritation. A conjunctival flap provides a regular surface for the placement of such a device, enhancing the tolerance of the prosthesis. ^,