An inverse pterygium is a condition where an abnormal adhesion forms, connecting the tissue lining the inside of the eyelid to the tissue covering the white of the eye. This scarring tethers two surfaces that should glide freely. This differs from a standard pterygium, which is a fleshy growth that originates on the white of the eye and extends onto the cornea. An inverse pterygium, more formally known as a symblepharon, is a fusion of tissues rather than an overgrowth.
Causes and Symptoms
The formation of a symblepharon is triggered by an abnormal healing process following an injury to the conjunctiva. Common causes include physical trauma to the eye, such as severe chemical or thermal burns. It can also develop as a complication of previous eye surgeries, where the raw surfaces of the conjunctiva heal by sticking to one another. This scarring response is the body’s attempt to repair damage, but it results in a restrictive band of tissue.
Beyond direct trauma, this condition is frequently associated with severe, immune-mediated inflammatory diseases. Conditions like ocular cicatricial pemphigoid (OCP) and Stevens-Johnson syndrome (SJS) are significant underlying causes. These are disorders where the body’s immune system mistakenly attacks the mucous membranes, including the conjunctiva, leading to chronic inflammation and severe scarring that can produce adhesions. Certain infections and, in rare cases, specific medications can also provoke the inflammatory response that results in a symblepharon.
Individuals often report persistent irritation, redness, and a feeling that something is in the eye. A defining symptom is restricted eye movement, as the tethered tissue prevents the eyeball from moving freely and can cause double vision (diplopia). In extensive cases, the adhesion can interfere with normal blinking and eyelid closure, leading to severe dry eye and compromising the health of the cornea. The visible band of tissue can also be a cosmetic concern for patients.
The Diagnosis Process
An ophthalmologist diagnoses an inverse pterygium during a comprehensive eye exam, considering the patient’s history of trauma, surgery, or systemic inflammatory disease. The primary diagnostic tool is the slit-lamp biomicroscope, which provides a magnified view of the eye’s structures.
During the exam, the physician assesses the connection between the palpebral conjunctiva (eyelid lining) and the bulbar conjunctiva (covering the white of the eye). The doctor looks for the characteristic fibrous band of tissue confirming the adhesion and evaluates its extent and thickness. This assessment helps determine the condition’s severity and guides the treatment approach.
Treatment Approaches
Managing an inverse pterygium is almost exclusively surgical, as the problem is a physical band of scar tissue that must be released. The goals of surgery are to remove the adhesion, restore the normal anatomical separation between the eyelid and the eyeball, and re-establish the deep pocket of the fornix.
The surgical procedure begins with the careful excision of the fibrous adhesion, where an ophthalmologist dissects the scar tissue to separate the fused conjunctival surfaces. Simply cutting the adhesion is insufficient, because leaving two raw tissue surfaces to heal in proximity creates a high risk of the adhesion reforming. To prevent this recurrence, the exposed areas of the sclera and the inner eyelid must be covered with a graft.
Two primary types of grafts are used to reconstruct the ocular surface. One common technique is amniotic membrane transplantation (AMT), where a thin layer of donated human amniotic tissue is placed over the bare sclera. The amniotic membrane acts as a biological bandage and scaffold, promoting proper epithelial healing while suppressing inflammation and scarring. Another technique is a conjunctival autograft, where a piece of healthy conjunctiva is harvested from another part of the patient’s own eye and transplanted to the defect site. In cases of extensive scarring where healthy conjunctiva is not available, a mucous membrane graft taken from the patient’s mouth may be used instead.
Recovery and Prognosis
After surgery, recovery focuses on controlling inflammation and preventing infection. Patients are typically prescribed a course of antibiotic and steroid eye drops. The antibiotic drops protect against bacterial infection while the surgical site heals, and the steroid drops are used to reduce the body’s natural inflammatory response, which helps minimize the risk of new scar tissue forming. An eye patch may be worn for a short time to protect the eye.
Follow-up appointments allow the surgeon to monitor the healing of the graft, check for any signs of recurrence, and manage any post-operative complications. Fornix-forming sutures or conformers, which are devices placed in the eye to maintain the depth of the pocket between the lid and eyeball, may be removed after several weeks.
The long-term outlook after surgical correction is favorable, especially with modern grafting techniques. Successful surgery can restore normal eye movement and resolve double vision. The risk of recurrence remains the primary concern, particularly for individuals whose symblepharon was caused by a chronic autoimmune condition like ocular cicatricial pemphigoid. If the underlying inflammatory disease is not well-managed with systemic medication, the continued inflammation can lead to new scarring and the return of adhesions.