Jin Kook Kim

Antibiotic susceptibility of conjunctival bacterial isolates from refractive surgery patients.

PURPOSE To determine the in vitro antibiotic susceptibility patterns of conjunctival bacterial flora isolated before surgery from patients undergoing refractive surgery. DESIGN In vitro laboratory investigation. PARTICIPANTS One hundred five eyes from 105 patients scheduled for refractive surgery at Balgensesang Ophthalmology Clinic between September 2005 and January 2006 were studied. Among 105 patients, 71 (67.6%) underwent LASIK using a femtosecond laser, 24 (22.9%) underwent LASIK using an automated microkeratome, 8 (7.6%) underwent LASEK, and 2 (1.9%) patients underwent phakic intraocular lens implantation. METHODS Preoperative conjunctival swab samples were inoculated directly in culture media at the bedside before topical anesthetic or antibiotic application. Blood agar, chocolate agar, thioglycolate broth, Sabouraud dextrose agar, and Ogawa media were used for bacterial, fungal, and mycobacterial cultures. MAIN OUTCOME MEASURES Minimum inhibitory concentrations (MICs) of ofloxacin (OFX), levofloxacin (LEV), gatifloxacin (GAT), moxifloxacin (MOX), gemifloxacin (GEM), and other commonly used antibiotics were determined using an E test. RESULTS From 105 patients, 73 (85%) coagulase-negative staphylococci (CNS), 2 (2.3%) Staphylococcus aureus, 1 (1.2%) Streptococcus pneumoniae, and 5 (4.8%) gram-negative bacilli were isolated. No fungi or mycobacteria were isolated. The MIC that would inhibit the growth of 90% of the tested bacterial isolates (MIC(90)) of OFX, LEV, GAT, MOX, and GEM for methicillin-susceptible CNS (n = 46) were 0.5 microg/ml, 0.19 microg/ml, 0.094 microg/ml, 0.047 microg/ml, and 0.023 microg/ml, respectively. The MIC(90) values for methicillin-resistant CNS (n = 27) were 32 microg/ml, 4 microg/ml, 1 microg/ml, 0.5 microg/ml, and 0.25 microg/ml, respectively (P<0.001). CONCLUSIONS The most effective against conjunctival bacteria isolated from refractive surgery patients were GEM, MOX, and GAT; however, resistance to earlier-generation fluoroquinolones (OFX and LEV) is increasing among methicillin-resistant CNS. It may be a therapeutic option to use newer fluoroquinolones in patients undergoing refractive eye surgery to reduce such infections as methicillin-resistant CNS. FINANCIAL DISCLOSURE(S) The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Laser in situ keratomileusis versus laser-assisted subepithelial keratectomy for the correction of high myopia

Purpose: To compare the visual and refractive outcomes of laser in situ keratomileusis (LASIK) and laser‐assisted subepithelial keratectomy (LASEK) in the treatment of high myopia. Setting: Institute of Vision Research, Department of Ophthalmology, College of Medicine, Yonsei University, and Balgeunsesang Ophthalmology Clinic, Seoul, South Korea. Methods: Four hundred seventy eyes of 240 patients with manifest refraction spherical components greater than –6.00 diopters (D) were assigned to 2 groups: 324 eyes (167 patients) were treated with LASIK and 146 eyes (73 patients), with LASEK. Uncorrected visual acuity (UCVA), best spectacle‐corrected visual acuity (BSCVA), remaining refractive error, corneal haze, and complications were followed in both groups for 12 months. Results: At 12 months, the mean spherical equivalent (SE) was within ±0.50 D of emmetropia in 205 eyes (63.3%) in the LASIK group and 81 eyes (55.5%) in the LASEK group and within ±1.00 D in 261 eyes (80.6%) and 104 eyes (71.2%), respectively. The UCVA was 20/25 or better in 269 LASIK eyes (83.0%) and 111 LASEK eyes (76.0%). There was more than a 1‐line loss of BSCVA in 4 LASIK eyes (1.2%) and 21 LASEK eyes (14.3%). The between‐group differences in SE, magnitude of cylinder, UCVA, and haze were statistically significant (P<.05). Conclusions: Both LASIK and LASEK were safe and effectively treated eyes with high myopia. Laser in situ keratomileusis provided superior results in visual predictability and corneal opacity.

Corneal endothelial decompensation after iris-claw phakic intraocular lens implantation

A 25-year-old man received iris-claw phakic intraocular lenses (pIOLs) (Artisan, Ophtec) of -11.5 diopters (D) in the right eye and -13.0 D in the left eye; both pIOLs had a 6.0 mm optic and 8.5 mm haptics. Twenty months postoperatively, the best corrected visual acuity was 20/400 in the right eye and 20/25 in the left eye. Slitlamp examination revealed microcystic bullae, keratic precipitates, stromal edema, and ciliary injection in both eyes. Central corneal thickness was 704 microm in the right eye and 639 microm in the left eye; specular biomicroscopy showed reduced endothelial cell density of 548 cells/mm(2) and 564 cells/mm(2), respectively. The pIOL in the right eye was eventually explanted.

Higher-order aberration changes after Implantable Collamer Lens implantation for myopia.

PURPOSE To investigate the changes in higher-order aberrations (HOAs) induced by implantation of Implantable Collamer Lenses (STAAR Surgical) and to explain them in relation to the surgical incision and optical properties. DESIGN Prospective, observational case study. METHODS This study included 56 eyes undergoing Implantable Collamer Lens insertion for myopic correction. The corneal incision size was determined according to the amount of astigmatism. HOAs were measured before surgery and 3 months after surgery in 25 eyes having small superior incision (<3.2 mm) surgery and in 31 eyes with large superior incision (3.2 to 4.5 mm) surgery. Changes in spherical aberration, coma, trefoil, and total HOAs (third to sixth order) were analyzed. Laboratory measurements of aberration profiles of Implantable Collamer Lenses with different optical powers were performed to validate clinical measurements. RESULTS In the small-incision group, trefoil (Z(3)(-3)) and spherical aberration changed significantly (P=.004). In the large-incision group, in addition to trefoil and spherical aberration, total HOA changed significantly (mean change, 0.13 ± 0.17; P=.001). Significant correlations were observed among the incision size, the astigmatism induced, and the trefoil induced. Induced trefoil showed a predominant pattern at the orientation of the incision meridian. Optical measurement of aberrations of the Implantable Collamer Lenses confirmed the postoperative negative spherical aberration. CONCLUSIONS HOA changes after Implantable Collamer Lens insertion were increased trefoil and induced negative spherical aberration. These changes may be explained by the effect of the corneal incision and the negative spherical aberration in the Implantable Collamer Lens, respectively.

Effect of amniotic membrane after laser-assisted subepithelial keratectomy on epithelial healing: clinical and refractive outcomes.

Purpose: To evaluate the effect of an amniotic membrane (AM) on reepithelialization time, corneal haze, and postoperative visual and refractive outcomes after laser‐assisted subepithelial keratectomy (LASEK) for myopia and myopic astigmatism. Setting: Department of Ophthalmology, Yonsei University College of Medicine, and Balgeunsesang Ophthalmology Clinic, Seoul, Korea. Methods: One hundred fifty‐two eyes of 84 patients with myopia or myopic astigmatism were prospectively evaluated for 6 months after LASEK. An AM was placed as a strip on the inferior limbus in 94 eyes of 54 patients after LASEK; 58 eyes of 30 patients served as the control group. Postoperative epithelial healing time, uncorrected visual acuity (UCVA), best corrected visual acuity, remaining refractive error, and corneal haze were examined. Results: The reepithelialization time was shorter in the AM group (2.40 days ± 0.94 [SD]) than in the control group (3.90 ± 0.97 days) (P<.001). At 6 months, 86 eyes (91.5%) in the AM group had a UCVA of 20/25 or better and 90 eyes (95.7%) had a UCVA of 20/40 or better; 48 eyes (82.8%) and 53 eyes (91.4%) in the control group had a UCVA of 20/25 or better and 20/40 or better, respectively. The mean spherical equivalent in the AM group was −0.48 ± 0.54 diopter (D) and in the control group, −0.94 ± 0.60 D (P<.001). The corneal haze was significantly less in the AM group than in the control group (P<.001). Conclusion: Amniotic membrane use after LASEK induced rapid epithelial healing with more favorable visual and refractive outcomes and lower corneal haze scores than conventional LASEK.

Changes in fusional vergence amplitudes after laser refractive surgery for moderate myopia

Purpose To analyze the effect of bilateral laser refractive surgery on fusional vergence amplitude and near point convergence in normal orthotropic myopic patients. Setting Cornea and refractive private practice, Seoul, South Korea. Design Prospective observational study. Methods Moderately myopic patients (2.0 to 6.0 diopters [D]) had bilateral laser refractive surgery with postoperative follow‐ups at 1 week and 1 and 3 months. Patients with manifest strabismus, previous strabismus surgery, amblyopia, absent or impaired binocularity, or planned monovision were excluded. The preoperative and postoperative examinations included uncorrected and corrected visual acuities; a prism cover test; evaluation of the convergence, divergence, and vertical fusion amplitude using a rotary prism; and near point convergence. Results The mean age of the 30 patients was 29 years ± 4 (SD). The mean preoperative refractive error was −4.10 ± 1.32 D in right eyes and −4.14 ± 1.37 D in left eyes. The convergence amplitude at near decreased 1 week and 1 month postoperatively, after which it progressively stabilized to near preoperative values. The convergence amplitude at far (break point) was not changed postoperatively; however, the convergence amplitude at far (recovery point) was increased at 1 month and 3 months (P=.008 and P=.003, respectively). There was a slight increase in near point convergence at 3 months (P<.001). Conclusions Although fusional vergence amplitudes at near and near point convergence changed after laser refractive surgery, the changes observed were small or transient. However, patients with latent phoria or strabismus should be warned before having refractive surgery. Financial Disclosure No author has a financial or proprietary interest in any material or method mentioned.

Corneal epithelial and stromal thickness changes in myopic orthokeratology and their relationship with refractive change

Purpose To investigate topographic changes in corneal epithelial thickness (CET) and stromal thickness following orthokeratology (OK) and to determine associated factors affecting refractive changes. Methods This study investigated the topographic changes in CET and stromal thickness in 60 myopic eyes that were fitted with OK lenses. CET and stromal thickness were obtained using spectral-domain optical coherence tomography (OCT) before and after OK lens wear. Changes in refractive error and corneal topography data were obtained. The correlation between refractive change and corneal thickness change, and various refractive, lens, and topographic parameters were analyzed using simple regression analysis. Results Mean refractive error changed by 1.75 ± 0.79 diopters (D). The mean CET of the center zone (2 mm in diameter), paracenter (2 to 5 mm annular ring: 1 to 2.5 mm from center), and mid-periphery (5 to 6 mm annular ring: 2.5 to 3 mm from center) changed by -8.4, -1.4, and +2.7 μm, respectively, after OK lens wear. There was an increase of 2.0, 3.3, and 3.9 μm, respectively, in the center, paracenter, and mid-periphery of the stroma. A larger refractive correction was associated with a flatter base curve of the lens, larger decrease in the central epithelium, and smaller treatment diameter in corneal topography. Conclusion OK lenses caused the central corneal epithelium to thin while the mid-peripheral epithelium and stroma became thicker. Refractive changes during OK are associated with changes in central epithelial thickness, while stromal changes did not contribute significantly.