Ex vivo confocal microscopy of human LASIK corneas with histologic and ultrastructural correlation.
OBJECTIVE
To perform confocal microscopy on postmortem human LASIK corneas and correlate these findings to histologic and ultrastructure evaluations.


METHODS
Prospective, consecutive, observational case series.


METHODS
Ninety postmortem LASIK corneas (47 patients) were evaluated for histopathology, of which 22 consecutive corneas (12 patients) were also evaluated by confocal microscopy. Six normal corneas (3 patients) served as controls.


METHODS
This observational case series involving 22 corneas from 12 patients with postoperative intervals from 1 month to 6.5 years after LASIK surgery were collected. The corneas were mounted in an artificial anterior chamber and perfused with balanced salt solution before confocal microscopy was performed on the center of the cornea. The corneas were then bisected and processed for light and transmission electron microscopy.


RESULTS
Confocal microscopy, along with histologic and ultrastructural correlations, demonstrated that the most prevalent alterations in the centers of LASIK corneas were a slightly thickened epithelium caused by focal basal epithelial cell hypertrophic modifications, random undulations in Bowman's layer over the flap surface, and a variably thick hypocellular primitive stromal interface scar. By using confocal microscopy, the interface wound was easily identified in 100% of the cases because numerous brightly reflective interface particles were always present in the hypocellular primitive stromal scar. These particles were found primarily to consist of organic cellular constituents, some of which were transient in nature.


CONCLUSIONS
After LASIK, active stromal wound healing in the central cornea results in the production of a hypocellular primitive stromal scar, whereas secondary tissue adjustments seem to cause the Bowman's layer undulations and the subsequent epithelial cell modifications. Most of the interface particles revealed by confocal microscopy in the region of the stromal scar are organic in nature and presumably innocuous to the cornea.
Dawson
Daniel G
DG
Department of Ophthalmology, Emory University School of Medicine, Atlanta, Georgia, USA.
Holley
Glenn P
GP
Geroski
Dayle H
DH
Waring
George O
GO
Grossniklaus
Hans E
HE
Edelhauser
Henry F
HF
D000328:Adult; D000368:Aged; D001485:Basement Membrane / Q000648:ultrastructure; D019573:Epithelium, Corneal / Q000473:pathology* / Q000648:ultrastructure; D005260:Female; D006801:Humans; D006984:Hypertrophy; D020731:Keratomileusis, Laser In Situ; D008297:Male; D018613:Microscopy, Confocal; D008875:Middle Aged; D009216:Myopia / Q000601:surgery; D011446:Prospective Studies; D013524:Surgical Flaps; D013997:Time Factors; D014945:Wound Healing