PURPOSE: The purpose of this study was to investigate the clinical efficacy of an optimized prolate ablation procedure for correcting residual refractive errors following laser surgery. METHODS: We analyzed 24 eyes of 15 patients who underwent an optimized prolate ablation procedure for the correction of residual refractive errors following laser in situ keratomileusis, laser-assisted subepithelial keratectomy, or photorefractive keratectomy surgeries. Preoperative ophthalmic examinations were performed, and uncorrected distance visual acuity, corrected distance visual acuity, manifest refraction values (sphere, cylinder, and spherical equivalent), point spread function, modulation transfer function, corneal asphericity (Q value), ocular aberrations, and corneal haze measurements were obtained postoperatively at 1, 3, and 6 months. RESULTS: Uncorrected distance visual acuity improved and refractive errors decreased significantly at 1, 3, and 6 months postoperatively. Total coma aberration increased at 3 and 6 months postoperatively, while changes in all other aberrations were not statistically significant. Similarly, no significant changes in point spread function were detected, but modulation transfer function increased significantly at the postoperative time points measured. CONCLUSIONS: The optimized prolate ablation procedure was effective in terms of improving visual acuity and objective visual performance for the correction of persistent refractive errors following laser surgery.
Coma ; Humans ; Keratectomy, Subepithelial, Laser-Assisted ; Keratomileusis, Laser In Situ ; Laser Therapy* ; Phosmet* ; Photorefractive Keratectomy ; Refractive Errors* ; Refractive Surgical Procedures ; Treatment Outcome ; 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

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

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

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

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

PURPOSE: To determine factors which influence forward displacement of the posterior surface of conea after performing LASIK with residual corneal thickness greater than 250 micro meter. METHODS: We studied 100 eyes of 50 myopic patients with an expected residual corneal thickness of greater than 250 micro meter after underwent LASIK. Residual corneal thickness, amount of laser ablation, intraocular pressure, spherical equivalent of cornea (keratometer), corneal diameter, corneal thickness, and anterior chamber depth were obtained at the preoperative stage, the postoperative one week, one month. Computed topography of cornea was performed between before and after LASIK. We evaluated the influence the forward displacement of posterior surface of conea by LASIK procedure. RESULTS: Average forward displacement of posterior surface of the cornea was 38+/-12 micro meter, and among preoperative factors, preoperative corneal thickness showed relatively high correlation with r=0.462 (P<0.001), having influence on the forward displacement. The displacement measured 1 month after LASIK was shown to decrease slightly (31+/-8 micro meter) compared that the displacement measured at 1 week after LASIK. CONCLUSIONS: Despite performing LASIK with residual corneal thickness of greater than 250 micro meter, if pre- operative corneal thickness is thin, one should be careful about anterior displacement of corneal posterior surface, and this change usually occurs within 1 week.
Anterior Chamber ; Cornea ; Humans ; Intraocular Pressure ; Keratomileusis, Laser In Situ* ; Laser Therapy

The effectiveness and safety of ureteroscopic holmium: YAG laser lithotripsy for managing ureteral calculi was evaluated. Ureteroscopic holmium. YAG laser lithotripsy was performed in 168 ureteral calculi (upper 27 cases, middle 33 cases and lower 108 cases). The results showed that the stone-free rate was 92.6% in the upper ureteral calculi, 93.9% in the middle ureteral calculi and 94.4% in the lower ureteral calculi, respectively. The complication rate was 4.8% (8 cases). It was suggested that ureteroscopic holmium: YAG laser lithotripsy is a highly effective and safe treatment modality for managing ureteral calculi.
Holmium ; *Lithotripsy, Laser/methods ; Ureteral Calculi/*therapy ; *Ureteroscopy

PURPOSE: To compare the effects of laser epithelial keratomileusis(LASEK) and laser in situ keratomileusis(LASIK) on tear secretion and tear film stability. METHODS: Sixty two eyes went through photorefractive surgery including LASEK(26 eyes, 14 patients) or LASIK(36 eyes, 18 patients) by the same surgeon from January in 2000 to April in 2000. Tear secretion was measured with schirmer test and tear stability was measured with tear breakup time(BUT) preoperatively and 2 months after procedures. RESULTS: In the LASEK group, the preoperative mean values were BUT, 7.46 sec; Shirmer, 11.92 mm, and at postoperative 2 months, they were 6.62 sec and 9.31 mm, respectively. The difference was statistically insignificant(P=0.51, P=0.22). In the LASIK group, the preoperative mean values were BUT, 7.56 sec; Shirmer, 10.56 mm. At 2 months, they were 5.56 sec and 7 mm, respectively. The difference was statistically significant(P=0.02, P=0.02). CONCLUSIONS: Our result showed that tear secretion seemed to be significantly decreased after LASIK, but not after LASEK.
Keratectomy, Subepithelial, Laser-Assisted ; Keratomileusis, Laser In Situ* ; Tears*

From April to October, 1988, 34 patients with ureteral calculi more than O.5 cm or smaller but impacted ureteral stone underwent pulsed dye laser lithotripsy under ureteroscopy. The results were as follows : 1. The locations of stone were upper ureter in 9(26.5%), mid ureter in 8(23.5%), lower ureter in 11(32.4%), and UVJ in 6(17.6%). 2. The success rates according to location were 66.7% in upper ureter, 87.5% in mid ureter, 91% in lower ureter, and 100% in UVJ and the average success rate was 85.3%. 3. The success rates according to stone size were 83% in 0.3-0.5 cm, 90% in 0.5-1.0 cm, and 75% in 1.0-2.3 cm. 4. The average procedure time was about 85 minutes, with a range of 30 to 120 minutes and the average hospitalization after laser therapy was about 3 days, with a range of 1 to 6 days. 5. There were 5 cases (14.8%) of failure due to upward migration of stone in 3 cases, ureteral injury in 1 case and ureteral stricture in 1 case. 6. Complications occurred in 10 patients (29.5 %), almost by ureteroscopy but laser induced complication was not found. Therefore, we confirm that laser lithotripsy is a safe and effective method for treatment of ureteral stone.
Constriction, Pathologic ; Hospitalization ; Humans ; Laser Therapy ; Lasers, Dye* ; Lithotripsy ; Lithotripsy, Laser ; Ureter* ; Ureteral Calculi* ; Ureteroscopy* ; Urinary Calculi