PURPOSE: To compare the efficacy, predictability, stability and safety of excimer laser photorefracive keratectomy(PRK) for mypia and photoastigmatic refractive keratectomy(PARK) for compound myopic astigmatism. METHODS: Two-hundred-three eyes(118 eyes <-7D spherical equivalent, 85 eyes> or =-7D spherical equivalent) received excimer laser correction for compound myopic astigmatism and 152 eyes(116 eyes <-7D, 36 eyes > or =-7D) for simple myopia. A VISX 20/20B VisionKeyTM excimer laser was used to perform either PARK or PRK. Visual acuity with and without correction, refraction, IOP, corneal haze, and topography were evaluated at 1, 3, 6, and 12 months postoperatively. All patients were followed up for more than 12 months. RESULTS: Postoperative refraction were generally stable after 3 months without significant early overcorrection. At 12 months, 110(94.8%) eyes that underwent PRK and 104(88.1%) eyes that underwent PARK achieved UCVA of 20/30 or better in the group who had lower than -7D correction. For eyes treated with -7D or more, these figures were 31(86.1%) eyes after PRK and 57(67.1%) eyes after PARK. The incidence of within 1D of plano refraction at 1 year follow-up were 97.4% after PRK and 93.2% after PARK in group who had lower than -7D correction. For eyes treated with -7D or more, there figures were 80.6% after PRK and 70.6% after PARK. CONCLUSIONS: Myopia with or without astigmatism was successfully treated in most of the eyes using PRK or PARK with VISX 20/20B VisionKeyTM excimer laser. The predictability and stability of the postoperative refraction during the first 12 months seem to be quite reliable. Futher improvement of excimer laser system and software should increase the clinical outcomes and safety of refractive procedures.
Astigmatism* ; Follow-Up Studies ; Humans ; Incidence ; Lasers, Excimer* ; Myopia* ; Photorefractive Keratectomy ; Visual Acuity

PURPOSE: To evaluate the effect of rotary epithelial scrubber and post-laser corneal chilling on clinical outcomes of excimer laser PRK (VISX 20/20B VisionKeyTM) METHODS: PRK with a rotary epithelial scrubber and post-laser chilled BSS irrigation was performed in 231 eyes of 141 patients (Group I: -4.33+/-0.98 D, July 1997~July 1999). Conventional PRK with mechanical epithelial removal was performed in 282 eyes of 181 patients (Group II: -4.33+/-0.99 D, September 1994~April 1997). A retrospective clinical data of two different PRK procedures was compared. RESULTS: Mean epithelial removal time was significantly short in group I (8.6+/-3.4 sec) than in group II (29.8+/-12.8 sec) (p<0.05). More rapid epithelial healing was achieved in group I (2.6+/-0.7 days) than in group II (2.8+/-0.7 days) (p<0.05). At 12 months, UCVA was 0.7 or better in 99.4% (162/163 eyes) of group I and 92.8% (77/88 eyes) of group II (p<0.05). At 12 months, 98.8% (161/163 eyes) in group I and 95.2% (79/83 eyes) in group II were within +/-1.0 D of emmetropia (p<0.05). After 2 years follow-up, there were no cases showing corneal haze worse than grade 1 in group I. CONCLUSIONS: Excimer laser PRK after precise removal of the epithelium with a rotary scrubber and post-laser corneal chilling provided more rapid epithelialization and visual recovery than conventional PRK. There was statistically significant improvement in clinical outcomes and occurrence of corneal haze in group I comparing with group II. We think that this excimer laser PRK technique be more ideal for the correction of mild to moderate myopia to avoid the serious flap complication of LASIK.
Emmetropia ; Epithelium ; Follow-Up Studies ; Humans ; Keratomileusis, Laser In Situ ; Lasers, Excimer* ; Myopia ; Photorefractive Keratectomy* ; Retrospective Studies

In order to get a good visual outcome following excimer laser photorefractive keratectomy(PRK) the centration of ablation is very important. In this study, the ablation center of excimer laser PRK using VISX 20/20 B(R) with VisionKeyTM(VISX, Inc. Santa Clara, CA) was evaluated by using corneal topography. Corneal topography was performed before operation and one month after operation to 190 eyes of 123 patients. The location and distance of center of ablation from center of the entrance pupil were calculated by using EyeSys Corneal Analysis System(R) with pupil-finding software(EyeSys Laboratories, Inc. Houston, TX). Supero-nasal displacement of ablation center occurred in 84 eyes(44%) after excimer laser PRK. The mean distance was 0.33 +/- 0.21mm(range: 0.02~1.36mm). The distance less than 0.5mm was found in 157 eyes(83%) and that between 0.5mm and 0.75mm was found in 26 eyes(14%). The decentering amount following excimer laser PRK was not depending on laterality(OD vs. OS), sex, age, amount of attempted correction(6D down vs. 6D up), type of software(ver 3.20 vs. 4.01) or type of procedure(PRK vs. PARK). In contrast, the second eye receiving excimer laser PRK showed a better centration of ablation than the first eye. And the centration results improved with surgeon's experience in the most recent 50 eyes(0.28 +/- 0.16mm). However, there was no relation between amount of decentration and visual improvement. In this study, it was found that decentering of ablation center less than 0.75mm did not influence the visual outcome in excimer laser PRK.
Cornea ; Corneal Topography ; Humans ; Lasers, Excimer* ; Photorefractive Keratectomy* ; Pupil

PURPOSE: To investigate the distribution of bacterial keratitis isolates and the shifting trends of in vitro antibiotic susceptibility of the isolates for inpatients with bacterial keratitis. METHODS: Three hundred ninety-two bacterial isolates with 366 positive culture cases from consecutive corneal scrapes of 988 clinically diagnosed bacterial keratitis inpatients hospitalized at Yeungnam University Hospital between January 1998 and December 2009 were retrospectively reviewed. The bacteriological profiles and in vitro resistance were evaluated in the first and second six-year periods. RESULTS: The percentage of positive cultures was 37.0% (366/988). The commonly isolated Gram-positive and Gram-negative organisms were S. epidermidis (98; 25.0%) and P. aeruginosa (41; 10.5%), respectively. The ratio of Gram-positive to Gram-negative isolates was 1.24:1. The Gram-positive isolates significantly decreased compared to the Gram-negative isolates in the last six-year period (45.3% versus 54.7%, respectively) relative to those in the first six-year period (66.1% versus 33.9%, respectively). S. epidermidis and S. aureus decreased, and E. cloacae, S. marcescens, and S. maltophilia increased in the last six-year period. The resistance of fluoroquinolone to the Gram-positive isolates, though not statistically significant, tended to increase to 34.1% from 21.5% (p=0.061), and the methicillin-resistant S. aureus tended to increase to 54.2% from 30.0% (p=0.055). CONCLUSIONS: S. epidermidis and P. aeruginosa were the most common bacterial keratitis isolates in Gram-positive and Gram-negative isolates. The Gram-positive isolates tended to decrease, though the Gram-negative organisms tended to increase in the last six-year period compared to the first six-year period. Empirical antibiotic selection should be based on local susceptibility patterns and distribution of bacterial isolates.
Cloaca ; Drug Resistance, Microbial ; Humans ; Inpatients ; Keratitis ; Methicillin Resistance ; Retrospective Studies

PURPOSE: To investigate the epidemiological, microbiological, and clinical characteristics of inpatients with infectious keratitis and also to elucidate risk factors for unimproved visual outcomes. METHODS: We performed a retrospective chart review of 167 eyes in 167 patients with infectious keratitis hospitalized between January 2005 and December 2007 at Yeungnam University Hospital. RESULTS: Keratitis cases were classified into four groups according to etiology: 92 bacterial, 43 herpes virus, 31 fungal, and 1 acanthamoeba. Culture positivity was 44.6% in bacterial keratitis and 22.6% in fungal keratitis, and KOH positivity of fungus was 48.4%. Of all the 55 isolated pathogens, the most commonly isolated microorganisms were S. epidermidis in Gram-positive bacteria, P. aeruginosa in Gram-negative bacteria, and Candida species in fungus. Epidemiologic characteristics such as male gender (59.9%), an age in the seventh decade (24.6%), farming occupation (40.1%), and trauma with vegetable matter (42.5%) were noted. Many fungal and bacterial keratitis cases were characterized by inadequate use of topical steroid when patients initially presented to our clinic. Visual outcomes were poorer in fungal keratitis than they were in other forms of keratitis. CONCLUSIONS: Risk factors for unimproved visual outcomes included an ulcer exceeding 3 mm in size and a fungal source. Therefore, a strong effort should be made to discern a differential diagnosis in infectious keratitis and to determine the appropriate early treatment for a successful treatment outcome.
Acanthamoeba ; Candida ; Diagnosis, Differential ; Eye ; Fungi ; Gram-Negative Bacteria ; Gram-Positive Bacteria ; Humans ; Inpatients ; Keratitis ; Keratitis, Herpetic ; Male ; Occupations ; Retrospective Studies ; Risk Factors ; Treatment Outcome ; Ulcer ; Vegetables ; Viruses

PURPOSE: To investigate the epidemiological, microbiological, and clinical characteristics of inpatients with infectious keratitis and also to elucidate risk factors for unimproved visual outcomes. METHODS: We performed a retrospective chart review of 167 eyes in 167 patients with infectious keratitis hospitalized between January 2005 and December 2007 at Yeungnam University Hospital. RESULTS: Keratitis cases were classified into four groups according to etiology: 92 bacterial, 43 herpes virus, 31 fungal, and 1 acanthamoeba. Culture positivity was 44.6% in bacterial keratitis and 22.6% in fungal keratitis, and KOH positivity of fungus was 48.4%. Of all the 55 isolated pathogens, the most commonly isolated microorganisms were S. epidermidis in Gram-positive bacteria, P. aeruginosa in Gram-negative bacteria, and Candida species in fungus. Epidemiologic characteristics such as male gender (59.9%), an age in the seventh decade (24.6%), farming occupation (40.1%), and trauma with vegetable matter (42.5%) were noted. Many fungal and bacterial keratitis cases were characterized by inadequate use of topical steroid when patients initially presented to our clinic. Visual outcomes were poorer in fungal keratitis than they were in other forms of keratitis. CONCLUSIONS: Risk factors for unimproved visual outcomes included an ulcer exceeding 3 mm in size and a fungal source. Therefore, a strong effort should be made to discern a differential diagnosis in infectious keratitis and to determine the appropriate early treatment for a successful treatment outcome.
Acanthamoeba ; Candida ; Diagnosis, Differential ; Eye ; Fungi ; Gram-Negative Bacteria ; Gram-Positive Bacteria ; Humans ; Inpatients ; Keratitis ; Keratitis, Herpetic ; Male ; Occupations ; Retrospective Studies ; Risk Factors ; Treatment Outcome ; Ulcer ; Vegetables ; Viruses

PURPOSE: To investigate the clinical results, recurrence rates, and recurrence-related risk factors of temporary amniotic membrane patch (TAMP) after excision of primary pterygium. METHODS: Recurrence grade was evaluated for 73 eyes with a mean follow-up of 15.5 months (range 9 to 56 months). Surgical results were classified into surgical success (G0/G1), conjunctival recurrence (G2), and corneal recurrence (G3). Recurrence rates were analyzed based on gender, age, Tan's preoperative grading system, horizontal and vertical length of the preoperative pterygium, the corneal involvement size of the preoperative pterygium, planned or unplanned removal of amniotic membrane, and epithelial healing time. Using Kaplan-Meier survival analysis, the cumulative proportion of integrated G0/G1 was evaluated. RESULTS: In the postoperative grading, 58 (79.5%) and 9 (12.3%) eyes were graded as clinically recurrence-free G0 and G1, respectively; 4 (5.5%) and 2 (2.7%) eyes were graded as clinically recurrence-occurred G2 and G3, respectively. The cumulative proportion of integrated recurrence-free G0/G1 at 24 months after surgery was 0.83 +/- 0.08. T3 of Tan's preoperative grading system was identified as the only risk factor for recurrence above G1 through multivariate logistic regression analysis (p = 0.02). CONCLUSIONS: The recurrence rate of the present TAMP study showed better results in comparison with 9.1 to 56.1% of recurrence rates in other studies. The TAMP has advantages of surgical procedure with ease, low complications, and low recurrence rates. Therefore, after surgical excision of primary pterygium, the authors concluded the TAMP is highly recommended for good clinical outcomes and low recurrence rates.
Amnion ; Eye ; Follow-Up Studies ; Logistic Models ; Pterygium ; Recurrence ; Risk Factors

PURPOSE: To investigate the shifting trends of pathogenic organisms, antibiotic resistance, and clinical characteristics of patients with Gram-positive bacterial keratitis and to elucidate the prognostic factors. METHODS: We performed a retrospective chart review of 152 isolates in 146 eyes with Gram-positive bacterial keratitis between January 1998 and December 2012. The study was divided into 5 periods for analysis of the bacteriological profiles and in vitro antibiotic resistance. The epidemiological and clinical characteristics were compared according to bacterial isolates. Logistic regression analysis was performed to determine the risk factors. RESULTS: Gram-positive bacterial keratitis tended to decrease and significant change in the distribution of isolates was not observed. Commonly isolated organisms were S. epidermidis (48.7%), S. aureus (25.0%), and S. pneumoniae (7.2%) in order of frequency. The resistance to fluoroquinolone tended to increase (p = 0.104) and resistance to gentamicin was significantly decreased (p = 0.01). S. epidermidis had the shortest corneal epithelium healing time (p = 0.035) and the most favorable visual outcome after treatment (p = 0.035) compared with the other species. Risk factors for poor visual outcomes included a best corrected visual acuity less than 0.1 at initial evaluation and an epithelial healing time greater than 10 days. CONCLUSIONS: Gram-positive bacterial keratitis tended to decrease and S. epidermidis was the most common isolate. The clinical prognosis was most favorable in S. epidermidis. The BCVA less than 0.1 at initial evaluation was an important risk factor for poor visual outcome and surgical treatment in Gram-positive bacterial keratitis.
Drug Resistance, Microbial ; Epithelium, Corneal ; Gentamicins ; Humans ; Keratitis* ; Logistic Models ; Pneumonia ; Prognosis ; Retrospective Studies ; Risk Factors ; Staphylococcus aureus ; Staphylococcus epidermidis ; Visual Acuity

PURPOSE: In this study we investigated pathogenic organisms, antibiotic susceptibility, and clinical characteristics of patients with Gram-negative bacterial keratitis and elucidated risk factors for poor visual outcomes. METHODS: The authors performed a retrospective chart review of 161 eyes (169 isolates) with Gram-negative bacterial keratitis between January 1998 and December 2012 at Yeungnam University Hospital. The study was divided into 5 periods for analysis of the bacteriological profiles and in vitro antibiotic sensitivity. The epidemiological and clinical characteristics were compared according to 3 groups (Pseudomonas species, Enterobacter species, and Serratia marcescens). Additionally, logistic regression analysis was performed to determine the risk factors. RESULTS: The prevalence of Gram-negative organisms increased from 34.7 to 73.2% between the 1st and 5th periods (p < 0.001). Pseudomonas spp. was the most commonly isolated organism (55 eyes, 32.5%) over the total period, followed by Enterobacter spp. (41 eyes, 24.3%) and Serratia marcescens (33 eyes, 19.5%). The effective antibiotics against Gram-negative bacterial pathogens isolated from culture were cefepime (94.5%), levofloxacin (93.4%), ciprofloxacin (93.0%), and amikacin (92.3%). The incidence was higher in the elderly over 60 years of age and in early adulthood patients in their 20s and 30s. The frequent predisposing factors were contact lens wearing and corneal trauma. S. marcescens had the shortest corneal epithelium healing time (p = 0.012) and the most favorable visual outcome after treatment (p = 0.004) compared with the other species. Risk factors for poor visual outcomes included a best corrected visual acuity less than 0.1 at initial evaluation (p < 0.001) and central corneal lesion (p = 0.027). CONCLUSIONS: Gram-negative bacterial keratitis tended to increase and Pseudomonas spp. was the most common isolate. The clinical prognosis was most favorable in S. marcescens. Early diagnosis of Gram-negative bacterial keratitis and appropriate antibiotic selection including cefepime, quinolone, or amikacin are recommended.
Aged ; Amikacin ; Anti-Bacterial Agents ; Causality ; Ciprofloxacin ; Early Diagnosis ; Enterobacter ; Epithelium, Corneal ; Humans ; Incidence ; Keratitis* ; Levofloxacin ; Logistic Models ; Prevalence ; Prognosis ; Pseudomonas ; Retrospective Studies ; Risk Factors ; Serratia ; Serratia marcescens ; Visual Acuity

PURPOSE: To evaluate the effect of the amount of cylindrical correction on the accuracy of geometric corneal center-adjusted ablation centration selected by the surgeon in advanced surface ablation-photorefractive keratectomy (ASA-PRK). METHODS: Ninety-five myopic eyes of 62 patients who underwent ASA-PRK were divided into three groups based on the amount of myopic cylindrical correction: Group 1 <-0.50 D, 22 eyes; Group 2 > or =-0.50 D and <-1.00 D, 45 eyes; Group 3 > or =-1.00 D, 28 eyes. The distances and distribution of the ablation centers from the entrance pupil center were analyzed by corneal topography at one month after ASA-PRK. Risk factors for decentration (>0.3 mm) were determined from patient-related factors such as gender, age, laterality, central corneal thickness, and order of procedure and surgery-related factors such as amount of spherical correction, ablation depth, vertical scale bar percentage, and learning effect of surgeon. RESULTS: Mean decentration was 0.26 +/- 0.15 mm (0.04 to 0.83 mm). There was no statistically significant difference in the amount of decentration among the three groups (p = 0.879). Superior-nasal displacement (53.7%) of the ablation center most frequently occurred after ASA-PRK. The amount of decentration among the three groups was not dependent on either patient-related or surgery-related factors. CONCLUSIONS: ASA-PRK using the surgeon-selected ablation center with adjustment toward the geometric corneal center was found to be highly accurate in ablation centration and did not influence the amount of ablation decentration regardless of the amount of myopic cylindrical correction.
Corneal Topography ; Displacement (Psychology) ; Eye ; Humans ; Learning ; Pupil ; Risk Factors