Management of Persistent Corneal Epithelial Defects, Thinning, and Perforation
Corneal surface disorders such as dellen, rheumatoid melt, and descemetocele can be managed by patching on a short-term basis. A partial tarsorrhaphy can sometimes be very effective and restore some vision to the eye.
Persistent epithelial defects and recurrent erosions of the cornea result from defects in the surface epithelium that fail to heal in a timely fashion (see Chapter 4). Trauma from the eyelids during blinking can retard reepithelialization, and if delayed, reepithelialization is further slowed by chronic changes in the basement membrane and anterior stroma. Patching may be successful over the short term. However, it compromises corneal oxygenation and impairs vision; also, some patients cannot tolerate closure of the eye while it is patched.
Bandage contact lenses
Application of a thin, oxygen-permeable, continuous-wear soft contact lens as a therapeutic bandage can protect loosely adherent remaining or regenerating epithelium from the “windshield-wiper” action of the blinking eyelids. Use of bandage contact lenses has significantly improved and simplified the management of recurrent erosions and persistent epithelial defects. These lenses help reduce stromal leukocyte infiltration and promote regeneration of basement membrane and restoration of tight epithelial–stromal adhesion without compromising corneal oxygenation, patient comfort, or vision.
Careful consideration should be given to the choice of a soft contact lens for patients with severe dry eye. In general, patients with dry eye run a high risk of infection with soft contact lenses; punctal occlusion should be performed in these patients to facilitate lens retention and comfort. Contact lenses with high oxygen transmissibility (eg, hydroxyethyl methacrylate [HEMA]–silicone polymer) are theoretically the most appropriate choice in this setting. Silicone lenses should be replaced every 2–4 weeks or as deposits accumulate on the lens. Frequent lubrication, prophylaxis with antibiotics, and close follow-up are crucial, especially in patients with decreased corneal sensitivity or dry eye. If a conventional soft lens is not tolerated, the use of an acrylic scleral lens may circumvent the problems encountered with a smaller-diameter hydrogel lens.
Continuous wear of a soft lens can relieve the symptoms of painful bullous or filamentary keratopathy. However, long-term use of a bandage contact lens can also lead to hypoxia, corneal pannus, limbal stem cell damage, and vascularization, all of which can compromise the success of future PK for vision rehabilitation.
Tarsorrhaphy should be considered for patients who have contact lens complications or a high risk of infection. The tarsorrhaphy procedure is described later in this chapter.
Treatment of corneal thinning/descemetocele
Corneal thinning may occur secondary to dellen where the tear film is uneven or may result from stromal inflammation and necrosis. In patients with dellen, the epithelium is intact, but there is an area of thinning next to an area of elevated or edematous tissue. In these cases, short-term patching may be sufficient.
In patients with corneal thinning down to the Descemet membrane (descemetocele) that is secondary to stromal infection or inflammation, the condition is much more serious because the epithelium is not intact and the patient is at risk for corneal perforation. The goals of therapy are to treat the inflammation or infectious component and to facilitate reepithelialization, which prevents progression of stromal collagenolysis.
The first order of therapy is to use appropriate antibiotics and anti-inflammatory medications. Topical steroids may reduce inflammation but should be used with caution with aggressive corneal melts. In patients with autoimmune conditions, conjunctival resection in the quadrant of a peripheral melt can be useful. In some cases, cyanoacrylate glue (also called cyanoacrylate adhesive) is helpful. Once the inflammation or infection has been controlled, a bandage lens or tarsorrhaphy may facilitate reepithelialization.
An alternative to using cyanoacrylate for a descemetocele is to use amniotic membrane that has been cut to the shape of the defect and then place a patch into the defect where the near-perforation is located. The patch and smaller amniotic membrane may be held in place with a larger amniotic membrane patch, nylon sutures, and a bandage contact lens, or by means of fibrin glue. With time, scar tissue will reinforce the deficient area and may circumvent the need for a corneal transplant.
Lindquist TP, Lee WB. Amniotic membrane transplantation. In: Basic Techniques of Ophthalmic Surgery. 2nd ed. San Francisco: American Academy of Ophthalmology; 2015:109–114.
Treatment of perforation
Some corneal perforations are small and seal spontaneously before ophthalmic examination, with no intraocular damage, prolapse, or adherence. These cases may require only treatment with systemic and/or topical antibiotic therapy, along with close observation. If a corneal wound is leaking but the anterior chamber remains formed, the leakage may be sealed with pharmacologic suppression of aqueous production (topical ocular hypotensive agent or systemic carbonic anhydrase inhibitor), patching, or a bandage contact lens. Generally, if these measures fail to seal the wound within 2 days, cyanoacrylate glue is another option (Fig 13-7). Perforations measuring more than 1–2 mm are usually not amenable to tissue adhesive and require supplemental tissue (Fig 13-8).
Figure 13-7 Clinical photographs showing (A) a central corneal melt and (B) glue and a contact lens applied to the melt.
(Courtesy of Robert W. Weisenthal, MD.)
Figure 13-8 Clinical photograph showing a corneal patch graft for a small central perforation unresponsive to gluing.
(Courtesy of Woodford S. Van Meter, MD.)
Cyanoacrylate glues are not FDA approved for ophthalmic use but have been used effectively and extensively over the past 3 decades to seal impending or small (<2 mm) perforations. Cyanoacrylate glue applied to thinned or ulcerated corneal tissue may prevent further thinning and can prevent leakage through the period of vascularization and repair. The adhesive plug is also thought to retard the entry of inflammatory cells and epithelium into the area, thus decreasing the rate of corneal melting. After the lesion is sealed, new stromal tissue may be laid down, and accompanying corneal vascularization may help ensure the integrity of the area by providing nutrients and antiproteases.
Cyanoacrylate glue can usually be applied on an outpatient basis using topical anesthetics. However, if adherent or prolapsed uvea in the leakage site or a flat chamber is encountered, the procedure may be best performed in the operating room using balanced salt solution and/or viscoelastic to re-form the anterior chamber. An eyelid speculum is necessary to keep the eyelids open and immobilized. Before the adhesive is applied, necrotic tissue and corneal epithelium should be removed from the involved area out to a 2-mm zone. The area should then be dried with a cellulose sponge.
The easiest way to apply glue is under biomicroscopic magnification. A small drop of the fluid adhesive is applied to the corneal wound with the tip of a 30-gauge needle or anterior chamber cannula. The glue does not polymerize on plastic, so an alternative way to apply the adhesive is to spread a small amount on the inside of the sterile plastic wrapping of any medical product that has been cut to a size slightly larger than the perforation. The glue can then be applied to the surface of the cornea in as thin a layer as possible using the plastic handle of a cellulose sponge or the wooden stick of a cotton-tipped applicator. The glue polymerizes completely within 20–60 seconds and usually adheres well to the deepithelialized surface.
The adhesive plug has a rough surface and can be irritating, so a bandage contact lens is necessary to protect the upper tarsal conjunctiva and to prevent the plug from being dislodged by blinking.
Kim HK, Park HS. Fibrin glue–assisted augmented amniotic membrane transplantation for the treatment of large noninfectious corneal perforations. Cornea. 2009;28(2):170–176.
Shaw C, Islam MN, Chakroborty S, et al. Tissue adhesive in ophthalmology. J Indian Med Assoc. 2010;108(7):460–461.
Suh LH, Akpek EK. Corneal gluing. In: Basic Techniques of Ophthalmic Surgery. 2nd ed. San Francisco: American Academy of Ophthalmology; 2015:161–164.
Excerpted from BCSC 2020-2021 series: Section 10 - Glaucoma. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.