Corneal wound healing and nerve morphology after excimer laser in situ keratomileusis in human eyes.
BACKGROUND
Our aim was to describe wound healing and nerve regeneration in the human cornea after excimer laser in situ keratomileusis.


METHODS
Excimer laser in situ keratomileusis was done in three human eyes 8 days, 54 days, and 4 months prior to enucleation. Acetylcholinesterase reaction was used to histochemically demonstrate the corneal nerves. Immunohistochemical methods were used to demonstrate the following wound healing proteins: cellular fibronectin, tenascin, transforming growth factor-beta 1, and alpha-smooth muscle actin.


RESULTS
All corneas healed without complication. No epithelial hyperplasia appeared and the Bowman's layer was smooth and acellular. An epithelial plug extending up to 100-300 microns under the flap margins was seen in all specimens. Regenerative nerve fiber bundles emerging from sharply cut anterior stromal nerves were observed, but the deeper nerves were normal. Restricted expression of fibronectin and tenascin was found at the wound area. All corneal cell types were positive for transforming growth factor-beta 1 antibody. Cells lining the limbal vessels were positive for alpha-smooth muscle actin antibody whereas the corneal cells were negative.


CONCLUSIONS
The nerve morphology showed only a few abnormalities, especially in deep stromal nerves. Epithelial plugs at the flap margins may maintain a delayed wound healing process for several months but otherwise the process remained active for a relatively short time.
Helsinki University Central Hospital, Eye Clinic, Finland.
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Latvala
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Barraquer-Coll
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Tervo
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D000110:Acetylcholinesterase / Q000378:metabolism; D000293:Adolescent; D000328:Adult; D000368:Aged; D003315:Cornea / Q000294:innervation / Q000502:physiology* / Q000601:surgery*; D003319:Corneal Stroma / Q000601:surgery; D003598:Cytoskeletal Proteins / Q000378:metabolism; D016326:Extracellular Matrix Proteins / Q000378:metabolism; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D054018:Lasers, Excimer; D008297:Male; D009416:Nerve Regeneration / Q000502:physiology*; D018903:Photorefractive Keratectomy; D016212:Transforming Growth Factor beta / Q000378:metabolism; D014276:Trigeminal Nerve / Q000473:pathology* / Q000502:physiology; D014945:Wound Healing / Q000502:physiology*
D003598:Cytoskeletal Proteins; D016326:Extracellular Matrix Proteins; D016212:Transforming Growth Factor beta; D000110:Acetylcholinesterase