Novel treatment shows promise for corneal neovascularization
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The avascular nature of the cornea is necessary for optical clarity and optimal vision.
Corneal neovascularization (NV) is a pathologic reaction that can be lethal to eyesight and is caused by many viral, traumatic, ischemic and foreign body-associated etiologies. Permanent vision loss is linked to lipid accumulation, scarring, irregular astigmatism and corneal clarity loss.
Source: Arnav Saroya, MS, FAICO, Soosan Jacob, MS, FRCS, DNB, Dhivya Ashok Kumar, MD, FRCS, FICO, FAICO, and Amar Agarwal, MS, FRCS, FRCOphth
Management of corneal neovascularization
Active inflammatory and traumatic corneal NV is often treated with topical corticosteroids. Topical corticosteroids, because of their wide anti-inflammatory characteristics, work best when applied early in tissue injury and corneal NV, but they can also cause glaucoma and cataracts, among other visual adverse effects. There is not enough proof that topical steroids can reverse chronic corneal NV or scar tissue. Many vasodestructive techniques, including photodynamic treatment, cautery, microneedle diathermy, suture ligation and argon laser photocoagulation, have had fairly unsatisfactory long-term outcomes. More recently, use of topical and subconjunctival anti-VEGF therapies has been reported, according to Mimouni and colleagues. Similar lack of long-term success has been shown with diathermy and anti-VEGF treatments. Options for corneal transplantation, including penetrating keratoplasty, are associated with a high risk for rejection and graft failure in eyes with corneal NV.
MMC intravascular chemoembolization
The efficacy of intravascular chemoembolization with different agents, including mitomycin C, has been reported for hepatocellular carcinoma. MMC probably restricts the ability of vascular endothelial cells to proliferate, which in turn limits the blood vessel’s endothelial monolayer’s ability to heal. This led to the novel hypothesis that MMC intravascular chemoembolization (MICE) could be a beneficial treatment for corneal NV, as reported by Mimouni and colleagues. With successful embolization, there have not been any reported cases of recurrence of corneal NV, although long-term follow-up is limited. If residual blood vessels remain, MICE can be repeated.
Indications and pre-injection workup
The common indication for MICE treatment in our series was lipid keratopathy secondary to corneal NV encroaching the visual axis. Patients with a previous trial of topical steroids for at least 1 month with persistent NV and no prior corneal vasodestructive or antiproliferative therapy were included. All patients underwent ophthalmic examination, slit lamp imaging, corneal topography and anterior segment OCT imaging.
Intravascular chemoembolization technique
The procedure was performed under aseptic precautions in the operating room using an operating microscope. Following the application of topical anesthesia (proparacaine or preservative-free lidocaine), the ocular area was irrigated with a topical 5% povidone-iodine solution. MMC (0.4 mg/mL) was used to partially fill a 1 cc syringe, which was then fitted with a 30-gauge needle. The greatest bore corneal vessel was identified immediately inside the limbus, and a tiny volume of MMC (0.01 mL to 0.05 mL) was injected. The bevel of the needle should be completely intrastromal to prevent the escape of MMC to the ocular surface (Figures 1a to 1c). The surgeon must also take care to avoid complete, full-thickness penetration of the cornea and subsequent intraocular injection of MMC into the anterior chamber. Balanced salt solution was used for meticulous irrigation of the ocular surface (to remove any remnant ocular surface MMC), and one drop of moxifloxacin 0.5% and prednisolone acetate 1% was applied at the end of the procedure. Regression of corneal NV was seen after injection (Figures 2a and 2b).
Summary
MICE is a new treatment for lipid keratopathy and visibly severe corneal NV. Long-term outcomes and negative consequences are unknown because the surgery is still relatively young. It should be avoided in eyes with epithelial defects to avoid further toxicity from the MMC, such as persistent epithelial defects and corneal stromal melts. However, MICE may be an alternative method and promising treatment option for active, acute corneal NV.
- References:
- Abdelfattah NS, et al. Int J Ophthalmol. 2015;doi:10.3980/j.issn.2222-3959.2015.01.32.
- Cursiefen C, et al. Graefes Arch Clin Exp Ophthalmol. 2001;doi:10.1007/s004170100313.
- Marelli L, et al. Cardiovasc Intervent Radiol. 2007;doi:10.1007/s00270-006-0062-3.
- Mimouni M, et al. Int Ophthalmol. 2022;doi:10.1007/s10792-022-02240-6.
- Shakiba Y, et al. Recent Pat Inflamm Allergy Drug Discov. 2009;doi:10.2174/187221309789257450.
- For more information:
- Amar Agarwal, MS, FRCS, FRCOphth, director of Dr. Agarwal’s Eye Hospital and Eye Research Centre, is the author of several books, including Phaco Nightmares: Conquering Cataract Catastrophes, Bimanual Phaco: Mastering the Phakonit/MICS Technique, Dry Eye: A Practical Guide to Ocular Surface Disorders and Stem Cell Surgery and Presbyopia: A Surgical Textbook. He can be reached at aehl19c@gmail.com; website: www.dragarwal.com.
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