Vascularization of the cornea is most frequently related to contact lens wear due to chronic hypoxia. The neovascularization is usually benign and appears as a superior corneal pannus with superficial vessels extending 1-2 mm into the cornea. However, deep vascular ingrowth is also possible, and vessels longer than 2 mm from the limbus pose a potential risk of stromal hemorrhage, lipid keratopathy and scarring. Significant corneal vascularization is also a complication of a variety of inflammatory, infectious, and autoimmune conditions such as interstitial keratitis, HSV keratitis, chemical injury, ocular cicatricial pemphigoid, Stevens-Johnson syndrome, keratoconjunctivitis (atopic, vernal, and superior limbic), and staphylococcal marginal keratitis.
The goal of treatment for corneal vascularization is to cause regression and elimination of the abnormal blood vessels. For contact lens wearers, lens wear should be suspended and after the cornea heals the patient should be refit with a contact lens having higher oxygen transmission. Topical steroids can promote vascular regression but require long-term treatment to be effective and therefore have the risk of causing elevated intraocular pressure and cataract formation. Other options for large or deep vessels are argon laser photocoagulation and the injection of subconjunctival Avastin in the area adjacent to the abnormal vessels. Large caliber vessels can be particularly difficult to eradicate because they tend to recanalize with the aforementioned therapies.
Transecting the vessels near the limbus can also be successful in more severe cases. This is an approach that I have successfully utilized in contact lens patients with both superficial and mid-stromal neovascularization. For the former, I used a 27g or 30g needle to disrupt each vessel in two or three places (to prevent recanalization), while for the latter, I severed focal areas of stromal vascularization with a diamond knife set at 300 microns (in essence creating a minimal corneal relaxing incision that did not induce any astigmatism). In all cases, I obtained informed consent, prepped the patient in a sterile fashion, administered topical antibiotic before and after the procedure, and prescribed a one-week course of topical antibiotic.
We have multiple methods at our disposal for the treatment of corneal vascularization. They can be used alone or in combination depending on the degree and severity of the abnormal vessels; however, they should be chosen appropriately for the specific situation after discussing the options with the patient.