Evaluation of pentoxifylline in the prevention of haze after photorefractive keratectomy in the rabbit.
BACKGROUND
Pentoxifylline (PTX) is a methylxanthine derivative that, besides its hemorrheologic properties, possesses multiple physiologic effects at the cellular level. It has been used in keloid prevention due to its ability to inhibit the secretion of collagen and glycosaminoglycans from activated fibroblasts.


METHODS
Ten New Zealand White (NZW) rabbits underwent a -7.00 diopters, 6.0 mm diameter photorefractive keratectomy after laser ablation of the epithelium with a VISX 20/20 excimer laser. The bare stroma was stained with fresh 0.5% dichlorotriazinyl aminofluorescein (DTAF). The procedure was performed on both eyes, 4 days apart. One eye received 1% Pentoxifylline qid and the other balanced salt solution qid as a control for 4 weeks, starting the same day of surgery. Two masked observers graded the amount of haze at 2, 4, 6, and 8 weeks after surgery using slit-lamp biomicroscopy. Three rabbits were sacrificed at 2 and 4 weeks followed by two rabbits at 6 and 8 weeks. The area between the DTAF-stained collagen to the base of the epithelium was measured using a digital image analyzer.


RESULTS
There was no statistically significant difference in the amount of haze either by slit-lamp microscopy or by histological analysis between the pentoxifylline-treated eyes and the controls at any time interval (Student's t-test: 0.16 to 0.92)


CONCLUSIONS
Pentoxifylline did not seem to affect haze formation in a PRK rabbit model. As no signs of toxicity were observed, further studies might examine higher concentrations or dose frequencies.
Francesconi
C M
CM
Cornea Consultants, Boston, Mass. 02114, USA.
Abad
J C
JC
Lim
J E
JE
Talamo
J H
JH
D000818:Animals; D003315:Cornea / Q000187:drug effects* / Q000473:pathology; D003318:Corneal Opacity / Q000209:etiology / Q000473:pathology / Q000517:prevention & control*; D004341:Drug Evaluation; D006401:Hematologic Agents / Q000494:pharmacology*; D054018:Lasers, Excimer; D009883:Ophthalmic Solutions; D010431:Pentoxifylline / Q000494:pharmacology*; D018903:Photorefractive Keratectomy / Q000009:adverse effects*; D011446:Prospective Studies; D011817:Rabbits; D011897:Random Allocation
D006401:Hematologic Agents; D009883:Ophthalmic Solutions; D010431:Pentoxifylline