Effect of laser in situ keratomileusis on tear secretion and corneal sensitivity.
OBJECTIVE
To study changes in corneal sensitivity and Schirmer I scores following laser in situ keratomileusis (LASIK) and the correlation between the two.


METHODS
Twenty-three patients who had LASIK at The Gimbel Eye Center, Toronto, Ontario, Canada, participated in the study. All were asymptomatic for severe dry eyes before surgery. All patients underwent a Schirmer test (without anesthetic), a filament corneal sensitivity test, and slit-lamp microscopy including staining with lissamine green preoperatively and at postoperative time intervals of 3 to 5 days, and 1 and 3 months.


RESULTS
No correlation was found between the difference in Schirmer test scores and the difference in corneal sensitivity, at any timepoint. A non-statistically significant trend toward a reduction in Schirmer values immediately after surgery was noted, with a return to slightly lower than baseline levels by 3 months. Corneal sensitivity was significantly decreased immediately after surgery and returned to preoperative levels by 3 months (P<.0001). There was a statistically significant effect of age, gender, and mean spherical equivalent refraction on corneal sensitivity (P<.0001) and a significant effect of age on the time trend (P=.02), but not for Schirmer levels or staining.


CONCLUSIONS
A significant reduction in corneal sensitivity immediately following surgery occurred, with a return to preoperative levels by 3 months. Schirmer test scores similarly decreased, although without statistical significance, and returned to near preoperative levels after 3 months. A statistically significant correlation between the reduction in tearing and reduction in corneal sensitivity after LASIK was not demonstrated.
Department of Ophthalmology, Toronto Western Hospital, University Health Network and the University of Toronto, Toronto, Ontario, Canada. drcohen58@hotmail.com
Adi
A
Michaeli
Allan R
AR
Slomovic
Kar
K
Sakhichand
David S
DS
Rootman
D000328:Adult; D004396:Coloring Agents; D003315:Cornea / Q000502:physiology*; D019781:Corneal Topography; D005260:Female; D006801:Humans; D006956:Hyperopia / Q000378:metabolism / Q000601:surgery; D020731:Keratomileusis, Laser In Situ; D008086:Lissamine Green Dyes; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000378:metabolism / Q000601:surgery; D012677:Sensation / Q000502:physiology*; D013666:Tears / Q000378:metabolism*
D004396:Coloring Agents; D008086:Lissamine Green Dyes