prevention of corneal haze following prk using extended wear contact lens khakshoor hamid

Prevention of corneal haze following PRK using extended wear

contact lens

Khakshoor HamidEslampoor AlirezaSaffarian Ladan

The authors have no financial interest in the subject matter of this e-poster.

Introduction

• Excimer laser photorefractive keratectomy (PRK) with adjunctive mitomycin C (MMC; MMC–PRK) has recently been used as an alternative to laser in situ keratomileusis (LASIK) for surgical correction of refractive errors.

• Corneal haze is a major disadvantage of PRK.

• It is characterized by subepithelial fibrosis caused by abnormal wound healing.

Introduction(continued)

• Mitomycin C is an alkylating agent that inhibits DNA and RNA replication and protein synthesis.

• It regulates fibroblast proliferation and differentiation, and subsequently blocks myofibroblast formation, which is responsible for corneal haze after PRK.

• Some concern exists for MMC long-term toxicity to keratocytes, endothelial cells, and intraocular structures.

Introduction(continued)

• Confocal microscopy has been employed by several investigators to monitor changes in keratocyte density during contact lens wear and showed keratocyte loss.

• These studies suggested that contact lens induced keratocyte loss could be attributed to hypoxic, cytokine-mediated, and mechanically induced effects.

• Stapelon et al. showed that extened-wear contact lens inhibit PMN recruitment.

Purpose

To evaluate the efficacy and safety of using extended wear contact lens in inhibiting haze formation after excimer laser photorefractive keratectomy (PRK).

METHODS

•A prospective, comparative interventional case series was conducted of 20 eyes (10 patients) with moderate myopia of 4 to 7 diopters.

•There were 1 man and 9 women with mean age of 27.7 years old.

•All eyes were evaluated preoperatively using complete ocular examination, corneal imaging by Orbscan and specular microscopy.

•Completely normal patients with pure myopia or myopic astigmatism with spherical equivalent of 4 to7 diopters were treated with PRK.

•For prevention of haze formation following PRK randomizely one eye of any patient was treated with MMC (0.02%) using a soaked cellulose sponge placed over the ablated area for about 35 seconds and an extended wear soft contact lens was applied to other eye for one month without using intraoperative MMC.

METHODS(Continued)

METHODS(Continued)

•All patients were followed for 3-7 months with mean follow-up time of 4.9 months.

•Refraction, uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), slit-lamp evidence of corneal opacity (haze) and specular microscopy were evaluated at 1 month, 3 months and last examination.

Results

•Corneal haze was not seen in none of eyes in both groups.

•Postoperatively the spherical equivalent decreased from -5.25 +/- 1.25 to -0.25 +/- 0.5 diopters (D) in MMC group and from -5.00 +/- 0.75 to -0.30 +/- 0.50 in contact lens group (P < 0.001).

•All eyes achieved uncorrected visual acuity of 20/20, 3 months postoperatively.

•There was no significant difference between last uncorrected visual acuities and remained refractive error in both groups.

•The difference between pre and post operatively endothelial cell count was not significant.

•Bacterial keratitis and other complications of bandage contact lens were not found in any eyes.

Results(Continued)

Conclusion

•Using extended wear bandage contact lens is an efficacious and safe method for inhibiting corneal haze following PRK.

References1.Carones F, Vigo L, Scandola E, et al. Evaluation of prophylactic use of mitomycin-C

to inhibit haze formation after photorefractive keratectomy. J Cataract Reftact Surg. 2002; 28: 2088-2095

2. Seiler T , Holscbach A , Derse M , Jean B, Genth U , Complication of myopic photorefractive keratectomy with the excimer laser ophthalmology 1994;101:153-160

3. Amano S , Shimizu K ,Excimer laser photorefractive keratectomy for myopia; two year follow up .J Refract Surg 1995:11(supp1) 5253-5260

4. Talamo JH , Gollamudi S , Green WR , De La Cruz , Filatov V , Stark WJ. Modulation of corneal wound healing after excimer laser keratomileusis using topical mitomycin c and steroids.Arch Ophthalmol 1991;109:1141-1146.

5. Leccisotli A . Mitomycine c in photorefractive keratectomy :effect on epithelialization and predictability.Cornea 2008 Apr, 27(3) 288-91

6. Bansal AK, Mustonen RK, McDonald MB. High resolution in vivo scanning confocal microscopy of the cornea in long term contact lens wear. Invest Ophthalmol Vis Sci. 1997;38:S138.

7. Jalbert I, Stapleton F. Effect of lens wear on corneal stroma: preliminary findings. Aust N Z J Ophthalmol. 1999;27:211–213.

8. Efron N, Perez-Gomez I, Morgan PB. Confocal microscopic observations of stromal keratocytes during extended contact lens wear. Clin Exp Optom. 2002;85:156–160

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prevention of corneal haze following prk using extended wear contact lens khakshoor hamid

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