Corneal biomechanics following epi-LASIK.
OBJECTIVE
To evaluate corneal biomechanical changes following epi-LASIK.


METHODS
In this prospective study of 51 patients, corneal hysteresis (CH), corneal resistance factor (CRF), and intraocular pressure (IOP) were assessed using the Ocular Response Analyzer (ORA, Reichert Technologies) preoperatively and at 1, 3, 6, and 12 months after epi-LASIK. Repeated measures analysis of variance (ANOVA) was used to compare changes over time (alpha=.05). Intraocular pressure was also measured by Goldmann applanation tonometry.


RESULTS
Corneal hysteresis decreased from 10.22±1.65 mmHg preoperatively to 8.17±1.25 mmHg at 1 month, 8.46±1.44 mmHg at 3 months, 8.63±1.31 mmHg at 6 months, and 8.53±1.49 mmHg at 12 months. Corneal resistance factor decreased from 10.01±1.80 mmHg preoperatively to 7.82±1.68, 8.03±1.85, 7.77±1.50, and 7.80±1.66 mmHg at 1, 3, 6, and 12 months, respectively. Repeated measures ANOVA showed a significant change over time for both CH and CRF (P<.0005). All measures of IOP changed significantly over time (P<.0005).


CONCLUSIONS
Epi-LASIK resulted in a significant change in CH and CRF postoperatively. Although some recovery occurred over time, CH, CRF, and IOP did not revert to preoperative levels.
Ophthalmology Service, Walter Reed Medical Center, Washington, DC 20307- 5001, USA. denise.sediq@amedd.army.mil
Denise S
DS
Ryan
Charles D
CD
Coe
Robin S
RS
Howard
Jayson D
JD
Edwards
Kraig S
KS
Bower
D000328:Adult; D001696:Biomechanical Phenomena; D003315:Cornea / Q000503:physiopathology* / Q000601:surgery; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007429:Intraocular Pressure; D020731:Keratomileusis, Laser In Situ / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000503:physiopathology / Q000601:surgery*; D011184:Postoperative Period; D011446:Prospective Studies; D013997:Time Factors; D055815:Young Adult