PURPOSE: We compared laser assisted in situ keratomileusis (LASIK) mode and photorefractive keratectomy (PRK) mode ablation methods in laser subepithelial keratomileusis (LASEK) surgery using the MEL-80 excimer laser. METHODS: All patients were followed up for a minimum of 1 year. The PRK mode group consisted of 46 eyes of 23 patients and the LASIK mode group consisted of 97 eyes of 56 patients. The central corneal thickness (CCT), ablation thickness, manifest refractive error and uncorrected visual acuity were compared preoperatively, 1 month and 1 year postoperatively. Spherical equivalent (SE) of cycloplegic refraction at postoperative 1 month and the uncorrected visual acuity (UCVA) ratios of 1.0 or better at postoperative 1 year were compared between the two groups to evaluate clinical efficacy. RESULTS: The SE of refractive error, CCT and target corneal ablation thickness of the two groups were not significantly different preoperatively. The PRK mode group obtained an actual ablation mean thickness of 82.8% of the target and the LASIK mode group obtained an actual ablation mean thickness of 94.1% of the target at postoperative 1 month. In each group, a statistically significant difference was observed between the actual corneal ablation thickness and target corneal ablation thickness. In the PRK mode group, the mean SE of postoperative 1 month cycloplegic refraction was +0.24 +/- 0.47 D and in the LASIK mode group, +0.87 +/- 0.54 D, indicating a statistically significant difference between the two groups. One year postoperatively, the UCVA ratios of 1.0 or better were 83% in the PRK mode group and 96% in the LASIK mode group, showing a statistically significant difference between the two groups. However, SE of manifest refractive error and CCT in the two groups were not statistically different at postoperative 1 year. CONCLUSIONS: The LASIK mode ablation method showed better results than the PRK mode ablation method in postoperative UCVA prognosis after LASEK surgery using the MEL-80 excimer laser.
Humans ; Keratectomy, Subepithelial, Laser-Assisted* ; Keratomileusis, Laser In Situ* ; Lasers, Excimer* ; Photorefractive Keratectomy ; Prognosis ; Refractive Errors ; Visual Acuity

PURPOSE: To evaluate the clinical effects of excimer laser refractive surgery on eyes with residual refractive error after implantation of ReSTOR(R) multifocal intraocular lenses. METHODS: We retrospectively reviewed the medical records of 10 eyes of 6 patients who had undergone cataract surgery with implantation of multifocal intraocular lenses. Photorefractive keratectomy (PRK) (5 eyes) and laser-assisted in situ keratomileusis (LASIK) (5 eyes) was performed on 10 eyes with residual refractive error. RESULTS: After cataract surgery and before laser surgery, the mean spherical equivalent (SE) was -0.34 +/- 0.89 D and the mean astigmatism was 2.08 +/- 0.55 D. Six months after laser surgery, the mean SE was -0.33 +/- 0.30 D (p = 0.354) and the mean astigmatism was 0.23 +/- 0.28 D. The changes in astigmatism between paired preoperative and postoperative values were statistically significant (p < 0.0001). At 6 months after surgery, uncorrected distance visual acuity significantly improved to 0.11 +/- 0.10 (log MAR) (p < 0.0001) There were no significant changes in the best corrected distance visual acuity and uncorrected near visual acuity (p = 0.073, p = 0.100). CONCLUSIONS: On the basis of predictability and stability, excimer laser surgery appears to be a clinically useful procedure to correct residual refractive error after implantation of ReSTOR(R) multifocal intraocular lenses.
Astigmatism ; Cataract ; Eye ; Humans ; Keratomileusis, Laser In Situ ; Laser Therapy ; Lasers, Excimer ; Lenses, Intraocular ; Medical Records ; Photorefractive Keratectomy ; Refractive Errors ; Refractive Surgical Procedures ; Retrospective Studies ; Visual Acuity

This research focuses on four cases of patients having undergone eximer laser photorefractive surgery who were diagnosed with adenoviral keratoconjunctivitis during the postoperative period and who later developed epidemic keratoconjunctivitis (EKC)-like keratitis. Two of the patients had undergone laser-assisted subepithelial keratectomy (LASEK), one had undergone laser in situ keratomileusis and one had photorefractive keratectomy. After the surgery adenoviral keratoconjunctivitis and recurrent late-developing EKC-like keratitis were observed in the patients. Recurrent late-developing EKC-like keratitis occurred in one of the patients, who had received LASEK as many as three times. The others had only one or two episodes.The corneal infiltrates of keratitis mainly occurred in the central cornea. Successful resolution of recurrent late-developing EKC-like keratitis was achieved through the use of topical steroids without sequelae and the final best-corrected visual acuity was as good as the base line. These keratitis infiltrates have been presumed to represent an immune response to the suspected adenoviral antigens deposited in corneal stroma during the primary adenoviral infection. Previous reports argued that patients with a history of adenoviral ketatoconjunctivitis were succeptible to adenoviral keratoconjunctivitis becoming reactivated; however, in our research, our patients had their first adenoviral infections after the eximer laser photorefractive surgery and reactivation was confirmed. We recommend that attention be paid to adenoviral infection after laser refractive operations, because these patients seem to have more frequent recurrences.
Adenovirus Infections, Human/diagnosis/drug therapy/*etiology ; Adult ; Conjunctivitis, Viral/diagnosis/drug therapy/*etiology ; *Corneal Surgery, Laser ; Eye Infections, Viral/diagnosis/drug therapy/*etiology ; Female ; Glucocorticoids/therapeutic use ; Humans ; Keratectomy, Subepithelial, Laser-Assisted ; Keratitis/diagnosis/drug therapy/*etiology ; Keratomileusis, Laser In Situ ; Lasers, Excimer/therapeutic use ; Photorefractive Keratectomy ; *Postoperative Complications ; Recurrence ; Young Adult

This article briefly explains surgical treatments of myopia. Laser refractive surgery using the excimer laser and/or femtosecond is the most commonly operated one. As the cornea has the greatest refractive power out of the ocular structures, the laser refractive surgery ablates the corneal stroma. Laser refractive surgeries are categorized by the surgical procedures basics: photorefractive keratectomy, laser in situ keratomilieusis (LASIK), laser epithelial keratomileusis, and Epi-LASIK. There are also some surgical treatment of myopia that does not use the laser ablation of the stroma. Intrastromal corneal ring segments implantation changes corneal shape which leads to the change of refractive power. Clear lens extraction reduces refractive power of crystalline lens by removal, and phakic intraocular lens implantation adds negative refractive power by implantation of intraocular lens. Patients are recommended to have a detailed consultation before choosing the surgical treatment based on their ocular status. There are several methods to treat myopia surgically, Laser reftractive surgery on cornea is most common method currently.
Cornea ; Corneal Stroma ; Humans ; Laser Therapy ; Lasers, Excimer ; Lens, Crystalline ; Lenses, Intraocular ; Myopia ; Phakic Intraocular Lenses ; Photorefractive Keratectomy ; Refractive Surgical Procedures

PURPOSE: This purpose of this report was to study trends in cataract and refractive surgeries conducted during the past twelve years and to compare results to previous reports from the ASCRS and New Zealand (NZ) in order to forecast future medical services. METHODS: We surveyed members of the Korean Society of Cataract and Refractive Surgery (KSCRS) every year from 1995 to 2006, and studied changes in cataract and refractive surgeries (RS). RESULTS: The duration of hospitalization has been gradually decreasing to the point that a one day hospitalization following surgery has become common. The rate of topical anesthesia use has significantly increased since 1998. Sutureless incision methods are now commonly practiced. The use of acryl IOL as an optic material has been gradually increasing for cataract surgeries. KSCRS members showed an interest in the special intraocular lenses as multifocal IOL. While Excimer laser PRK was the most popular refractive surgery during the first stage, KSCRS members increasingly prefer LASIK to the Excimer laser PRK. Regression of the corrected visual acuity, dry eye, night halo, and flashes were the most common complications following refractive surgeries. Medical disputes related to PRK and LASIK have been gradually increasing throughout the study period. CONCLUSIONS: We confirm that the KSCRS practice styles for cataract and RS are similar to those of the ASCRS and NZ. We infer a world-wide trend from the comparison of these three societies.
Adult ; Cataract Extraction/statistics & numerical data/*trends ; Humans ; Keratomileusis, Laser In Situ/statistics & numerical data/trends ; Laser Therapy/statistics & numerical data/trends ; Lasers, Excimer ; Lenses, Intraocular/statistics & numerical data/trends ; Middle Aged ; Ophthalmology/statistics & numerical data/*trends ; Photorefractive Keratectomy/statistics & numerical data/trends ; Professional Practice/statistics & numerical data/*trends ; Questionnaires ; Refractive Surgical Procedures/statistics & numerical data/*trends ; Republic of Korea ; Societies, Medical

PURPOSE: To evaluate the clinical effect of photorefractive keratectomy (PRK) and laser assisted in situ keratomileusis (LASIK) on eyes with anisometropia due to residual astigmatism after cataract surgery. METHODS: We retrospectively reviewed the medical records of 11 eyes of 11 patients who had undergone cataract surgery from March 2002 to November 2005. PRK (2 eyes) and LASIK (9 eyes) was performed on 11 eyes with refractive myopic or mixed astigmatism over 1.5D after cataract surgery. RESULT: Before laser surgery, the mean astigmatism was 3.23+/-1.02D and the mean spherical equivalent (SE) was -2.27+/-1.43D. Six months after laser surgery, the mean SE was 0.66+/-0.58D and the mean astigmatism was 0.73+/-0.39D. The changes in mean manifest SE and astigmatism were statistically significant between paired preoperative and postoperative values (p<0.05). At 6 months after surgery, the mean uncorrected visual acuity and best corrected visual acuity significantly improved to 0.65+/-0.17 and 0.84+/-0.11, respectively. Three eyes (27.3%) developed mild haze and were treated without sequelae. There were no other complications. CONCLUSIONS: Excimer laser surgery appears to be a clinically useful procedure to correct residual astigmatism after cataract surgery.
Anisometropia ; Astigmatism ; Cataract ; Eye ; Humans ; Keratomileusis, Laser In Situ ; Laser Therapy ; Lasers, Excimer ; Medical Records ; Photorefractive Keratectomy ; Refractive Surgical Procedures ; Retrospective Studies ; Visual Acuity

BACKGROUNDThe recent studies have shown that visual performance might be affected by the ocular aberration after the corneal refractive surgery, and try to minimize it. This study was to investigate the effects of photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) on the higher order of wavefront aberration and analysis of their characteristics.

METHODThis prospective study involved 32 eyes with similar refractive powers (-5.0 D to -6.0 D preoperatively). LASIK and PRK were performed with the same parameters of 6 mm diameter optical zone and 7 mm diameter transition zone ablation. Wavefront aberrations were tested using a ray tracing technique preoperatively and 3 months postoperatively. Three measurements were obtained for each condition; the root mean squared wavefront error (RMS), values for overall wavefront aberrations and each order of the Zernike aberrations were analyzed using the Matlab software. The 2-tailed t test was used for statistical analysis.

RESULTSOverall higher order aberrations were increased from (0.550.26) microm preoperatively to (0.930.37) microm for PRK and (0.790.38) microm for LASIK postoperatively. This was a 1.69 fold increase in the PRK group (t = 3.95, P < 0.001) and a 1.43 fold increase in the LASIK group (t = 2.60, P < 0.05). At 3 months, the mean RMS value for higher-order (3rd to 6th) were significantly increased compared with the corresponding preoperative values (P < 0.05). The fourth order aberrations, spherical like aberration, were dominant by a 2.64 fold in PRK and a 2.31 fold in LASIK. Different influences of the PRK group and LASIK group were shown in the various zernike components. The statistically significant differences were seen in C(4)(0), C(4)(+4), C(5)(+1), C(5)(+3), C(5)(+5) and C(6)(+2) of the PRK group and C(3)(-3), C(4)(0), C(5)(-5), C(5)(+5), C(6)(-2) of the LASIK group, which represents a 7.42, 3.58, 9.21, 2.72 and 5.3 fold increases in PRK group, and 6.40, 10.80, 11.06, 3.47 and 6.09 fold increases in LASIK group, respectively. C(3)(-3) in LASIK was higher and C(5)(+1) and C(5)(+3) were lower than those in the PRK group. C(4)(0) (spherical aberration) values were similar between PRK and LASIK, however, C(3)(-1) and C(3)(1) (coma) in LASIK were higher than those in PRK, but these differences are of no statistical significance.

CONCLUSIONSPRK and LASIK may increase ocular higher-order aberrations, but they both have their own features. The difference between the two types of surgery may be correlated with the change of the corneal shape, the conversion of biodynamics, the healing of the corneal cut, and re-structured corneal epithelium and/or the stroma.

Adolescent ; Adult ; Cornea ; pathology ; Humans ; Keratomileusis, Laser In Situ ; adverse effects ; Lasers, Excimer ; Photorefractive Keratectomy ; adverse effects ; Postoperative Complications ; etiology ; Prospective Studies ; Vision Disorders ; etiology ; Visual Acuity

PURPOSE: To evaluate the safety and results of the prophylactic use of 0.02% mitomycin C (MMC) to inhibit haze formation after excimer laser photorefractive keratectomy (PRK) for high myopia in eyes that were not good candidates for laser in situ keratomileusis (LASIK) because of inadequate corneal thickness. METHODS: On thirty eyes with high myopia (-6.0 to -10.13 diopters), PRK with intraoperative topical 0.02% MMC application was performed. Visual acuity, refraction, keratometry, corneal haze, central corneal thickness, corneal endothelium, repair of corneal epithelium, and other complications were evaluated for 1 year. RESULTS No eyes showed any BCVA loss, and some even presented a BCVA increase, except in one case: one eye had lost a line 1 year after PRK. At 1 year after surgery, the spherical equivalent was within +/-0.5 D of the desired refraction in 73.33% of the cases, and 86.67% were within +/-1.0 D of the intended refraction. At 3 months after surgery, the mean corneal haze scale stabilized at about 0.22, and decreased further thereafter. Central corneal thickness increased steadily postoperatively, whereas endothelial density decreased significantly, however, the percentage of hexagonal cells and coefficient of variation in cell area showed no change. Epithelial regeneration was complete within 4 days, and there were no other complications. CONCLUSIONS: The prophylactic use of a 0.02% MMC applied intraoperatively after PRK produced lower haze rates and a better visual outcome. But, due to the decrease in endothelial cell density, the safety of MMC can be determined only after long-term observation.
Endothelial Cells ; Endothelium, Corneal ; Epithelium, Corneal ; Keratomileusis, Laser In Situ ; Lasers, Excimer ; Mitomycin* ; Myopia* ; Photorefractive Keratectomy* ; Regeneration ; Visual Acuity

PURPOSE: To evaluate the safety and results of the prophylactic use of 0.02% mitomycin C (MMC) to inhibit haze formation after excimer laser photorefractive keratectomy (PRK) for high myopia in eyes that were not good candidates for laser in situ keratomileusis (LASIK) because of inadequate corneal thickness. METHODS: On thirty eyes with high myopia (-6.0 to -10.13 diopters), PRK with intraoperative topical 0.02% MMC application was performed. Visual acuity, refraction, keratometry, corneal haze, central corneal thickness, corneal endothelium, repair of corneal epithelium, and other complications were evaluated for 1 year. RESULTS No eyes showed any BCVA loss, and some even presented a BCVA increase, except in one case: one eye had lost a line 1 year after PRK. At 1 year after surgery, the spherical equivalent was within +/-0.5 D of the desired refraction in 73.33% of the cases, and 86.67% were within +/-1.0 D of the intended refraction. At 3 months after surgery, the mean corneal haze scale stabilized at about 0.22, and decreased further thereafter. Central corneal thickness increased steadily postoperatively, whereas endothelial density decreased significantly, however, the percentage of hexagonal cells and coefficient of variation in cell area showed no change. Epithelial regeneration was complete within 4 days, and there were no other complications. CONCLUSIONS: The prophylactic use of a 0.02% MMC applied intraoperatively after PRK produced lower haze rates and a better visual outcome. But, due to the decrease in endothelial cell density, the safety of MMC can be determined only after long-term observation.
Endothelial Cells ; Endothelium, Corneal ; Epithelium, Corneal ; Keratomileusis, Laser In Situ ; Lasers, Excimer ; Mitomycin* ; Myopia* ; Photorefractive Keratectomy* ; Regeneration ; Visual Acuity

Surgical modalities to correct hyperopia include photorefractive keratectomy (PRK), laser in situ keratomileusis (LASIK), Ho:YAG laser thermal keratoplasty (LTK), conductive keratoplasty (CK), phakic IOL, and refractive lens exchange. Excimer laser-based techniques, which include LASIK, LASEK, and PRK, are currently the most popular forms of surgery to correct not only myopia and astigmatism but also hyperopia. These techniques have been reported to be safe and effective for both primary surgeries and enhancements. However, various complications related to the flap and loss of best corrected visual acuity associated with a smaller optic zone, decentration, and irregular ablation caused by longer treatment time in high hyperopia over +5 diopter can have adverse effects on visual outcomes. The development of non-excimer laser-based techniques offers viable alternatives for laser vision correction techniques. More recent non-excimer-based thermal refractive techniques include LTK and CK. Earlier forms of thermal techniques showed a lack of predictability and stability, resulting in no further development of them. Recently, CK, a laserless, radiofrequency-based technique, has been approved by the FDA for the correction of low to moderate hyperopia even though the refractive instability has not been solved yet. In high hyperopia, lens approach like phakic IOL or refractive lens exchange instead of corneal surgery is preferred. ICL (Implantable contact lens) and Artisan is the most popular lens model that has well proven clinical results concerning its safety and effectiveness. Accommodative IOL or multifocal IOL could be the solution for pseudophakic presbyopia in refractive lens exchange in the future.
Astigmatism ; Corneal Transplantation ; Hyperopia* ; Keratectomy, Subepithelial, Laser-Assisted ; Keratomileusis, Laser In Situ ; Lasers, Excimer ; Myopia ; Photorefractive Keratectomy ; Presbyopia ; Visual Acuity