**Subconjunctival Mitomycin C Injection into Pterygium Decreases Its Size and Reduces Associated Complications**

Mohammad Hossien Davari, Hoda Gheytasi and Esmat Davari

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/60090

#### **Abstract**

Purpose: To evaluate the safety and efficacy of subconjunctival injection of low dose mi‐ tomycin C (MMC) in the management of pterygium.

Patients and Methods: This study was carried out from February 2006 to April 2007 in the eye clinic of Vali-e-Asr Hospital of Birjand University of Medical Sciences. Forty eyes with primary pterygia received 0.02 mg MMC (0.1 ml of 0.2 mg/ml solution, Kyowa Hak‐ ko Kogyo Co. Ltd., Tokyo, Japan) subconjunctivally injected into the body of the ptery‐ gium. Patients were followed at one day, one week, one month, six months and one year after injection. Patients were examined at all visits for conjunctivally erythematic, epithe‐ lial defects; intraocular pressure; topography; keratometry; and other complications (complete slit-lamp examinations).

Results: The only complications after subconjunctival MMC injection were mild chemo‐ sis, long discomfort, and redness in the site of injection for four days, which were seen in six patients (15%). Toxicity of MMC was not observed in any case. The size of pterygia reduced in 83% of cases and progression were not seen in any case. The amount of astig‐ matism reduced in 70% cases (mean 0.27 diopter).

Conclusion: Subconjunctival injection of MMC is an effective treatment and allows exact titration of MMC delivery to the activated fibroblasts and minimizes epithelial toxicity but long term follow up is required.

**Keywords:** pterygium, mitomycin C, subconjunctival, complication

## **1. Introduction**

Pterygium is a fibro vascular overgrowth of degenerative conjunctiva tissue that extends across the limbos and invades the cornea [1, 2].

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The risk factors for pterygium development include exposure to ultraviolet (UV) light, dust, wind, heat, dryness, and smoke [2].

The primary indication for surgical removal of pterygium is visual acuity reduction. The cause of this phenomenon is extension of remaining scar to visual axis [3]. Irregular astigmatism, reduced vision, discomfort and irritation, difficulty with contact lens wear, refractive surgery, and cosmetic deformity are other reasons for surgical intervention [3].

A wide range of surgical procedures for removal of pterygia have been reported [4]. However, recurrences after excision have been reported to be very high. For example, it has been reported as high as 30% to 80% with the bare sclera technique [5]. The conjunctiva auto graft transplan‐ tation effectively prevents pterygium recurrence [6, 7, 8].

MMC is an antibiotic, antineoplastic agent that selectively inhibits the synthesis of DNA, cellular division, and protein [9]. The mechanism of action of MMC seems to be inhibition of fibroblast proliferation at the level of the episclera [10, 11, 12].The benefit of MMC is having prolonged, but not permanent, effectiveness on suppressing human fibroblasts [13, 14, 15].

Although multiple studies have reported recurrence rates of approximately 5% to 12% with the use of topical MMC [16, 17], this technique has been associated with rare but significant conjunctival and corneal toxicity [16]. In an attempt to decrease ocular morbidity, the intrao‐ perative administration of MMC was applied directly to the sclera bed, which has gained increasing acceptance. Recently, combined pterygium removal with intraoperative MMC and conjunctiva auto grafting for primary and recurrent pterygium has been described [18].

The purpose of this study was to evaluate effectiveness by applying MMC at low concentration and low volume.
