Laser in situ keratomileusis results of DOS and windows software versions for the Nidek EC-5000 excimer laser using the same nomogram.

PURPOSE: To compare the results of laser in situ keratomileusis (LASIK) correction for myopia and myopic astigmatism between the previous DOS software version and the Windows software version for the Nidek EC-5000 excimer laser, using the same nomogram. METHODS: This retrospective review included 2021 eyes (980 patients) after LASIK using the Nidek EC-5000 excimer laser. Of these, 1,632 eyes were corrected with the DOS software version and the other 389 eyes were corrected with the Windows software version of the laser. Both groups were treated with the same surgical nomogram. Minimum follow-up time was 6 months. Patients were classified into range of myopia: low, moderate, and high. RESULTS: Postoperative uncorrected visual acuity was not statistically significantly different between the two groups in any range of refractive error. There was no loss of best spectacle-corrected visual acuity for any patient. Uncorrected visual acuity equal to or better than 20/40 was achieved in 96.3% of eyes in the Windows version group and 94.9% in the DOS version. CONCLUSION: Results for the correction of myopia or myopic astigmatism were similar using the Nidek EC-5000 excimer laser with either the DOS software version or Windows software version, with the same surgical nomogram.

Evaluation of the reliability of the Nidek MK-2000 microkeratome for laser in situ keratomileusis.

PURPOSE: To evaluate the performance of the Nidek MK-2000 microkeratome in corneal flap creation for laser in situ keratomileusis (LASIK) in Asian eyes and the simplicity of its use for the beginner. METHODS: A prospective study of 200 Asian eyes was performed. The corneal flaps were created using the Nidek MK-2000 microkeratome 130-microm and 160-microm thickness plates with 8.5- and 9.5-mm suction rings. Ease of obtaining suction was evaluated and measurements were done for flap thickness, flap diameter, hinge size, and hinge-to-center-of-pupil distance. RESULTS: Subjectively, even in small eyes, the procedure of obtaining the required suction and creating a good flap was easy and reliable with the Nidek MK-2000 microkeratome. Average flap thickness was 120.52 +/- 16.49 microm (range, 84 to 162 microm) for the 130-microm thickness plate with the 8.5-mm suction ring. Mean flap diameter was 9.16 +/- 0.43 mm, mean hinge size was 4.96 +/- 0.36 mm, and mean hinge-to-center-of-pupil distance was 4.16 +/- 0.28 mm. With the 9.5-mm suction ring, mean flap thickness was 122.06 +/- 18.54 microm (range, 84 to 149 microm), mean flap diameter was 9.85 +/- 0.35 mm, mean hinge size was 5.28 +/- 0.36 mm, and mean hinge-to-center-of-pupil distance was 4.49 +/- 0.27 mm. For the 160-microm plate with a 8.5-mm suction ring, the flap thickness was 172.71 +/- 27.49 microm (range, 121 to 203 microm), flap diameter was 9.13 + 0.37 mm, mean hinge size was 5.02 +/- 0.29 mm and mean hinge-to-center-of-pupil distance was 4.21 +/- 0.29 mm. There were no complications of corneal flap creation. CONCLUSION: The Nidek MK-2000 microkeratome was effective, safe, and reliable, even in small eyes.

Laser in situ Keratomileusis Corneal Flap Creation With the Nidek MK-2000 and the Carriazo Barraquer Microkeratomes.

PURPOSE: To evaluate the performance of the Nidek MK-2000 and the LSK Carriazo Barraquer microkeratomes in the creation of corneal flaps for laser in situ keratomileusis (LASLK). METHODS: A prospective randomized study of 55 eyes of 30 patients who underwent LASLK was performed. Twelve corneal flaps were created hy the Nidek MK-2000 microkeratome (160-/«n head), 30 corneal flaps by the Carriazo Barraquer 160-¿m head microkeratome, and 13 corneal flaps by the Carriazo Barraquer 180-/tm head microkeratome. Flap thickness (evaluated by ultrasonic pachymetry), flap diameter, hinge size, and hinge-to-centerof-pupil distance were measured. RESULTS: For the Nidek MK-2000 microkeratome, mean flap thickness was 149.58 ± 25.61 µ?? (range, 94 to 186 /im), flap diameter was 8.81 ± 0.34 mm (range, 8.4 to 9.1 mm), hinge size was 4.31 ± 0.45 mm (range, 3.9 to 4.8 mm), and hinge-to-centerof-pupil distance was 3.79 ± 0.70 mm (range, 3.9 to 4.7 mm). For the Carriazo Barraquer 160-/im head microkeratome, mean flap thickness was 123.9 ± 22.28 jttm (range, 104 to 155 /an), flap diameter was 9.08 ± 0.44 mm (range, 8.7 to 11 mm), hinge size was 4.04 ± 0.61 mm (range, 4 to 6 mm), and hinge-tocenter-of-pupil distance was 4.37 ± 0.24 mm (range, 4 to 4.5 mm). For the Carriazo Barraquer I80-/«n head microkeratome, mean flap thickness was 167.23 ± 24.92 ^m (range, 145 to 198 /nn), flap diameter was 9.12 ± 0.18 mm (range, 9 to 9.4 mm), hinge size was 4.21 ± 0.39 mm (range, 4 to 5 mm), and hinge-to-center-of-pupil distance was 4.47 ± 0.24 mm (range, 4.2 to 4.7 mm). There was no correlation between corneal curvature and flap diameter. No case was aborted due to improper corneal flap creation. An epithelial defect was found in 5 eyes after reverse movement of the Nidek MK2000 microkeratome. CONCLUSION: The Nidek MK-2000 and the Carriazo Barraquer microkeratomes were effective, safe, and reliable in the creation of corneal flaps for LASLK. [J Refract Surg 2000;16(suppl): S272-S275].

Corneal iron deposits after laser in situ keratomileusis.

PURPOSE: To report the occurrence and features of corneal iron line deposition after laser in situ keratomileusis (LASIK). METHODS: We evaluated 83 eyes undergoing LASIK. Corneal iron line deposition was analyzed with respect to preoperative spherical equivalent, attempted correction, and postoperative time interval. RESULTS: Thirty-five (42.2%) of 83 eyes displayed a distinctive brown-colored corneal iron line of variable density in a ring or patch configuration near the margin of the ablated zone in the overlying corneal flap epithelium. The appearance of this iron line correlated positively with time after surgery (>3 months) and preoperative spherical equivalent (>-4.5 diopters). CONCLUSIONS: Corneal iron line deposition in a ring or patch can be associated with previous LASIK surgery. This iron deposition within the margin of the ablated zone may offer insights into the dynamics of epithelial cell hyperplasia as well as basal cell proliferation, differentiation, and migration after LASIK.