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Algorithms↗
Biomedical subjects
Guy M Kezirian
Publications and source records attributed to Guy M Kezirian.
Femtosecond laser versus mechanical keratome flaps in wavefront-guided laser in situ keratomileusis: prospective contralateral eye study.
PURPOSE: To compare the outcomes of wavefront-guided laser in situ keratomileusis (LASIK) performed using the IntraLase femtosecond laser with the outcomes using the Hansatome mechanical microkeratome. SETTING: Private clinic, Overland Park, Kansas, USA. METHODS: In a prospective contralateral-eye study performed under institutional review board supervision, 51 consecutive patients (102 eyes) had bilateral wavefront-guided LASIK for myopia using the Alcon LADARVision laser. One eye of each patient was randomized to have the flap created with the IntraLase femtosecond laser and the other flap using a standard compression head Hansatome microkeratome. All other treatment parameters were the same. RESULTS: The IntraLase group had significantly better mean uncorrected visual acuity (UCVA) at all intervals from 1 day to 3 months postoperatively. The mean spheroequivalent at 3 months was more myopic with the Hansatome (-0.34 diopter [D] +/- 0.28 [SD]) than with the IntraLase (-0.19 +/- 0.24 D) (P<.01). The mean residual astigmatism at 3 months was also significantly higher in the Hansatome group than in the IntraLase group (0.32 +/- 0.25 D and 0.17 +/- 0.20 D, respectively) (P<.01). The differences in UCVA persisted after spheroequivalent outcomes were controlled for but equilibrated when the analysis was modified to control for manifest postoperative astigmatism. Aberrometry showed significantly higher astigmatism and trefoil in the Hansatome group. Recovery of corneal sensation and epithelial integrity was similar between groups. CONCLUSIONS: The statistically better UCVA and manifest refractive outcomes after LASIK with the IntraLase femtosecond laser may be the result of differences in postoperative astigmatism and trefoil. These findings are consistent with previous findings of better astigmatic outcomes with the IntraLase laser and may have clinical significance for wavefront-guided treatments.
Adult↗
Systematic evaluation of wavefront-guided outcomes.
PURPOSE: To present a format for reporting outcomes of aberrometer-guided refractive procedures. SETTING: SurgiVision Consultants, Inc., Scottsdale, Arizona, and Food and Drug Administration, Center for Devices and Radiological Health, Rockland, Maryland, USA. METHODS: Reports of standard refractive and visual outcomes (uncorrected visual acuity, manifest refractive spherical equivalent, best spectacle-corrected visual acuity) should be provided for any refractive surgery report. Comparison of postoperative uncorrected visual acuity to preoperative best spectacle-corrected visual acuity should be included. Aberration reports should convert 2nd-order terms to refractions (measured in diopters) and use standard refractive reporting methods. Changes in coma, spherical aberration, and root-mean-square changes should be described using statistical methods for aggregate data. Underlying statistics should be reported. RESULTS: Aberration changes are well described by the mean error of the attempted versus achieved outcomes, comparison of the mean changes, and stability over time. Ancillary plots include histogram representation of the postoperative scores. Additional reports of visual function should be included, as appropriate. CONCLUSION: Use of standardized tables and graphs permits qualitative and quantitative comparison of outcomes of refractive treatment with wavefront-guided lasers. Modifications of the recommended formats can be expected over time.
Corneal Surgery, Laser↗
Comparison of the IntraLase femtosecond laser and mechanical keratomes for laser in situ keratomileusis.
PURPOSE: To compare laser in situ keratomileusis (LASIK) results obtained with the femtosecond laser (IntraLase Corp.) to those obtained using 2 popular mechanical microkeratomes. SETTING: Private practice, Greensboro, North Carolina, USA. METHODS: This retrospective analysis compared LASIK outcomes with the femtosecond laser to those with the Carriazo-Barraquer (CB) microkeratome (Moria, Inc.) and the Hansatome microkeratome (Bausch & Lomb, Inc.). The 3 groups were matched for enrollment criteria and were operated on under similar conditions by the same surgeon. RESULTS: There were 106 eyes in the IntraLase group, 126 eyes in the CB group, and 143 eyes in the Hansatome group. One day postoperatively, the uncorrected visual acuity (UCVA) results in the 3 groups were similar; at 3 months, the UCVA and the best spectacle-corrected visual acuity results were not significantly different. A manifest spheroequivalent of +/-0.50 diopter (D) was achieved in 91% of eyes in the IntraLase group, 73% of eyes in the CB group, and 74% of eyes in the Hansatome group (P<.01). IntraLase flaps were significantly thinner (P<.01) and varied less in thickness (P<.01) than flaps created with the other devices. The mean flap thickness was 114 microm +/- 14 (SD) with the IntraLase programmed for a 130 microm depth, 153 +/- 26 microm with the CB using a 130 microm plate, and 156 +/- 29 microm with the Hansatome using a 180 microm plate. Loose epithelium was encountered in 9.6% of eyes in the CB group and 7.7% of eyes in the Hansatome group but in no eye in the IntraLase group (P =.001). Surgically induced astigmatism in sphere corrections was significantly less with the IntraLase than with the other devices (P<.01). CONCLUSIONS: The IntraLase demonstrated more predictable flap thickness, better astigmatic neutrality, and decreased epithelial injury than 2 popular mechanical microkeratomes.
Adult↗
Subjective assessment of mesopic visual function after laser in situ keratomileusis.
The authors' study evaluated subjective reports of mesopic visual function after LASIK for spherical and spherocylindrical myopia and evaluated whether age, pupil size, treatment amount, residual postoperative refractive error, or other factors correlated with subjective findings. Preoperative, 3-month, and 6-month subjective patient questionnaires were administered. Results for questions about glare with night driving and glare with bright lights were tallied and evaluated using standard statistical methods. The results indicated that subjective reports of mesopic visual function after myopia LASIK improve overall. Worsened symptoms are most likely to occur in eyes with poor refractive outcomes. Correction of residual refractive errors may improve night driving and glare symptoms after LASIK.
Adolescent↗