Enhancement outcomes after photorefractive keratectomy and laser in situ keratomileusis using topographically guided excimer laser photoablation

PURPOSE

To evaluate the efficacy and safety of topographically guided excimer laser photoablation to retreat unsuccessful myopic and hyperopic photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK).

SETTING

Eye Clinic, San Salvatore Hospital, University of L'Aquila, L'Aquila, Italy.

METHODS

At least 3 months after primary PRK (Group A) or primary LASIK (Group B), 48 eyes of 42 patients were submitted to PRK or LASIK enhancements. The eyes were treated with an excimer laser linked to a computerized videokeratography unit with a topographically supported customized ablation workstation.

RESULTS

The mean follow-up was 27.8 months +/- 8.2 (SD). In Group A, the uncorrected visual acuity (UCVA) changed from 0.5 +/- 0.7 logarithm of the minimum angle of resolution (logMAR) (range 20/600 to 20/200) to 0.1 +/- 0.7 logMAR (range 20/60 to 20/20); the mean best spectacle-corrected visual acuity (BSCVA) changed from 0.1 +/- 0.7 logMAR (range 20/50 to 20/20) to 0 +/- 0.7 logMAR (range 20/50 to 20/20) after the enhancement. In Group B, the UCVA changed from 0.7 +/- 0.8 logMAR (range 20/600 to 20/40) to 0.1 +/- 0.7 logMAR (range 20/40 to 20/20); the mean BSCVA improved from 0.2 +/- 0.8 logMAR (range 20/30 to 20/20) to 0 +/- 1.3 logMAR (range 20/25 to 20/20) after surgery.

CONCLUSIONS

The enhancements using topographically guided excimer laser photoablation with a topographically supported customized ablation method resulted in satisfactory and stable visual outcome with good safety and efficacy after unsuccessful PRK and LASIK.

Clinical results of excimer laser photorefractive keratectomy for high myopic anisometropia in children: four-year follow-up

PURPOSE

To evaluate the visual and refractive results of multizonal photorefractive keratectomy (PRK) for high myopic anisometropia and contact-lens intolerance in children.

SETTING

Department of Ophthalmology, Masaryk University Hospital, Brno, Czech Republic.

METHODS

Twenty-one patients aged 7 to 15 years with high myopic anisometropia had multizonal PRK in the more myopic eye and were retrospectively analyzed. The scanning-slit Nidek EC-5000 excimer laser was used. Postoperatively, patients were reviewed at 1 and 3 days, 1 week, and 1, 3, 6, 12, 18, 24, 36, and 48 months. The examination included cycloplegic refraction, uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), biomicroscopy, grading of postoperative haze, corneal topography, pachymetry, intraocular pressure, biometry, orthoptic status, binocular vision (BV), and fundus evaluation. The safety, efficacy, predictability, and stability of the procedure were evaluated. Long-term binocular vision outcome was analyzed. All patients completed a 4-year follow-up.

RESULTS

The mean preoperative spherical equivalent (SE) refraction was 8.93 diopters (D) +/- 1.39 (SD) (range -6.75 to -11.75 D) and the mean postoperative SE, -1.66 +/- 0.68 D (range -0.50 to -2.75 D) (P <.05). The mean preoperative UCVA of 0.034 +/- 0.016 increased to 0.35 +/- 0.15 (P <.05) postoperatively. The mean preoperative BSCVA was 0.53 +/- 0.19 and changed to 0.64 +/- 0.16 postoperatively. The safety index was 1.21. No eye lost a line of BSCVA; 9 eyes gained 1 line, and 5 eyes gained 2 lines. The efficacy index was 0.66. The postoperative uncorrected and best spectacle-corrected BV were the same or improved. No eye had +3 haze. There were no significant complications.

CONCLUSIONS

Photorefractive keratectomy was safe and effective in correcting high myopic anisometropia in children who were contact-lens intolerant. It provided good visual results and preserved or improved BV over the 4-year follow-up.

Photorefractive keratectomy in children

PURPOSE

To evaluate photorefractive keratectomy (PRK) in pediatric patients who fail traditional methods of treatment for myopic anisometropic amblyopia and high myopia.

SETTING

Nonhospital surgical facility with follow-up in a hospital clinic setting.

METHODS

Photorefractive keratectomy was performed in 40 eyes of 27 patients. The patients were divided into 4 groups based on the type of myopia: myopic anisometropic amblyopia (15 eyes/13 patients), bilateral high myopia (20 eyes/10 patients), high myopia post-penetrating keratoplasty (3 eyes/2 patients), and combined corneal scarring and anisometropic amblyopia (2 eyes/2 patients). All procedures were performed under general anesthesia using the VISX 20/20 B laser and a multizone, multipass ablation technique. Appropriate corneal fixation was achieved with appropriate head positioning (turn and tilt) and an Arrowsmith fixation ring. Myopia was as high as -25.00 diopter (D) spherical equivalent (SE), but no treatment was for more than -17.50 D SE.

RESULTS

The mean SE decreased from -10.68 D to -1.37 D at 1 year, a mean change of -9.31 D. At 1 year, the mean best corrected visual acuity improved from 20/70 to 20/40 in the entire group. Forty percent of eyes were within +/-1.0 D of the targeted refraction. There was no haze in 59.5% of eyes. Three eyes initially had 3+ haze; 1 improved to 2+ and 2 required repeat PRK with significant haze reduction. Five eyes (3 patients) with greater than -17.00 D SE myopia before PRK (range -17.50 to -25.00 D) had 3.42 D more effect than predicted (range 0.50 to 5.50 D). A functional vision survey demonstrated a positive effect on the children's ability to function in their environments after the laser treatment.

CONCLUSION

Photorefractive keratectomy in children represents another method of providing long-term resolution of bilateral high myopia and myopic anisometropic amblyopia.

Flap Measurements With the Hansatome Microkeratome

PURPOSE

To evaluate flap thickness, flap diameter, and hinge length during laser in situ keratomileusis (LASIK) and to correlate these measurements with preoperative keratometric power, central corneal thickness, and patient refraction, gender, and age.

METHODS

In this prospective study of 50 eyes of 28 patients (mean age 31 +/- 6.6 yr; range, 24 to 43 yr) results of LASIK for myopia were analyzed (mean spherical equivalent refraction of -7.16 +/- 1.69 D; range, -2.75 to -13.50 D). Corneal flaps were created using the Hansatome microkeratome (Baush & Lomb Surgical) with a 160-microm plate and a 9.5-mm suction ring. Corneal thickness was evaluated using an ultrasonic 50-MHz pachymeter (Sonogage Corneo Gage Plus) and the mean keratometric power was measured with a Corneal Analysis System videokeratographic unit (EyeSys). Data were analyzed using t-test, Pearson product moment correlation coefficient, and Spearman's rho non-parametric correlation coefficients.

RESULTS

Mean corneal flap thickness was 142.6 +/- 20.8 microm (range, 107 to 177 microm), mean flap diameter was 9.9 +/- 0.3 mm (range, 9.2 to 10.5 mm), and mean hinge length was 6.2 +/- 0.4 mm (range, 5.2 to 7 mm). Statistically significant correlations (P<.05) were found between mean keratometric power and flap hinge length, mean keratometric power and flap diameter, preoperative spherical equivalent refraction and flap diameter, corneal thickness and flap hinge length, as well as patient age and corneal thickness.

CONCLUSIONS

The Hansatome microkeratome was an effective and safe instrument in the creation of corneal flaps for LASIK. Consideration of preoperative keratometric power and corneal thickness may help to reduce or avoid complications.

Advances in refractive surgery: 1975 to the present

PURPOSE

To review the major advances in the field of refractive surgery occurring over the past 25 years.

METHODS

Literature review.

RESULTS

The major developments in refractive surgery over the past 25 years are reviewed.

CONCLUSIONS

The past 25 years have witnessed great changes in refractive surgery. As a result of advancements in technology, instrumentation, and technique, we have seen improvements in the treatment of all types of ametropias. In this article, we review some of the successes and failures of the past quarter-century.

Videokeratographic changes after laser in situ keratomileusis to correct high myopia

PURPOSE

To evaluate the videokeratographic changes and patterns after laser in situ keratomileusis (LASIK) in high myopia using computerized videokeratography.

SETTING

San Salvatore Hospital, Chair of Ophthalmology, University of L'Aquila, L'Aquila, Italy.

METHODS

Forty-one eyes of 26 patients treated with no-suture nasal-hinged flap LASIK for an attempted mean spherical equivalent correction of -13.9 diopters (D) +/- 4.1 (SD) (range -8.0 to -22.0 D) were evaluated. Mean patient age was 35.2 +/- 9.8 years. Mean follow-up was 15.1 +/- 6.7 months (range 6 to 26 months).

RESULTS

Thirty-five eyes (85.4%) were within +/- 2.0 D of the planned correction, with a refractive error greater than 3.0 D in the 7.3% of eyes. Mean central corneal power decreased from 43.2 +/- 1.8 D (range 38.70 to 47.40 D) to 35.8 +/- 3.8 D (range 30.3 to 42.6 D). Mean preoperative corneal astigmatism decreased from 1.2 +/- 0.9 D (range 0.2 to 4.2 D) to 0.9 +/- 0.9 D (range 0.2 to 3.3 D). Videokeratographic qualitative analysis showed corneal shape changes within 15 days after surgery. Corneal patterns then stabilized, and 37 eyes (90.3%) had no significant modifications in corneal refractive power after 1 month.

CONCLUSION

After LASIK in highly myopic eyes, videokeratographic maps showed corneal power stabilized within 1 month in most eyes and there was no irregular astigmatism if the treatment was well centered.