Jin Young Choi

Dynamic vaulting changes in V4c versus V4 posterior chamber phakic lenses under differing lighting conditions.

PURPOSEnTo compare vaulting changes in eyes implanted with V4c and V4 implantable collamer lenses (ICLs) under differing lighting conditions.nnnDESIGNnNoninterventional, cross-sectional comparative observational case series.nnnMETHODSnFifty-six eyes of 38 patients implanted with V4c ICLs, and 54 eyes of 28 patients implanted with V4 ICLs were enrolled and analyzed. Anterior chamber depth, pupil size and postoperative vaulting were evaluated using a Visante optical coherence tomography system under photopic and mesopic conditions 1 month postoperatively. Refractive errors, keratometry values, axial lengths, intraocular pressures, anterior chamber volumes, and central corneal thicknesses were also recorded.nnnRESULTSnNo significant differences were noted in anterior chamber depth between photopic and mesopic conditions in either group. Significant decreases in vaulting and pupil size were detected under photopic conditions in both groups. Moreover, vaulting changes in eyes implanted with V4c ICLs were significantly larger than those in eyes implanted with V4 ICLs.nnnCONCLUSIONSnV4c ICL vaulting decreased more prominently under photopic conditions than did V4 ICL vaulting. Therefore, postoperative vaulting under mesopic and photopic conditions should be considered when interpreting the vaulting of eyes implanted with V4c ICLs.

Lower Laser Energy Levels Lead to Better Visual Recovery After Small-Incision Lenticule Extraction: Prospective Randomized Clinical Trial

PURPOSEnTo determine the effect of lowering laser energy on clinical outcomes in small-incision lenticule extraction (SMILE).nnnDESIGNnProspective randomized clinical trial.nnnMETHODSnA total of 151 patients (151 eyes) with moderate myopia scheduled for SMILE were included: 58 eyes received SMILE with low energy (100, 105, and 110 nJ; L-SMILE group) and 93 with conventional energy (115-150 nJ; C-SMILE group). Patients received complete ophthalmic examinations preoperatively and over 3xa0months postoperatively.nnnRESULTSnUncorrected distance visual acuity (logMAR UDVA) 1xa0day and 1xa0week postoperatively was significantly better in L-SMILE than in C-SMILE (P < .001 and Pxa0= .005, respectively). There was no significant difference between the groups at 1 and 3xa0months. L-SMILE induced significantly fewer corneal aberrations compared with C-SMILE at 1xa0week and 1xa0month postoperatively (both P < .01), but there were no significant differences at 3xa0months. Though there was no difference in logMAR UDVA over the postoperative period between the 100, 105, and 110 nJ subgroups, there was a significant difference in logMAR UDVA on postoperative day 1 between L-SMILE and each subgroup in which an energy level of 115 nJ or higher was used. Furthermore, logMAR UDVA on postoperative day 1 showed a significant correlation with laser energy (rxa0=xa00.451, P < .001) and multiple linear regression analysis revealed that energy level was the only independent factor associated with logMAR UDVA on postoperative day 1 (P < .001).nnnCONCLUSIONSnSMILE using femtosecond energy of less than 115 nJ facilitates better visual acuity with less induction of corneal aberrations in the early postoperative period.

Changes in posterior corneal elevations after combined transepithelial photorefractive keratectomy and accelerated corneal collagen cross-linking: retrospective, comparative observational case series

BackgroundTo compare the changes in anterior and posterior corneal elevations after combined transepithelial photorefractive keratectomy (PRK) and accelerated corneal collagen cross-linking (CXL) and after PRK.MethodsMedical records of 82 eyes of 44 patients undergoing either combined transepithelial PRK and CXL (PRK-CXL group) or transepithelial PRK (PRK group) were examined retrospectively. Changes in anterior and posterior corneal elevations were calculated by fitting an 8.0-mm diameter best-fit sphere and best-fit toric ellipsoid (BFTE) to the corneal shape with a fixed eccentricity of 0.4 using Scheimpflug tomography (Pentacam HR; Oculus Optikgeräte GmbH, Wetzlar, Germany) preoperatively and 6xa0months postoperatively.ResultsIn anterior corneal elevation, both groups demonstrated a similar trend of a forward displacement of peripheral anterior corneal surface and a backward displacement of central anterior corneal surface. In posterior corneal elevation, a forward displacement of peripheral posterior corneal surface was induced in both groups, along with a backward displacement of central posterior corneal surface, regardless of the calculation method. The magnitudes of displacement of peripheral and central posterior corneal surfaces were significantly smaller in the PRK-CXL group than in the PRK group. Moreover, the PRK-CXL group showed a backward displacement of posterior corneal surface at maximum corneal elevations when the BFTE was used as the reference surface.ConclusionsTransepithelial PRK combined with prophylactic CXL significantly reduced the magnitudes of displacement of peripheral and central posterior corneal surfaces, with the radius of the BFTE was set to 8.0-mm on the Scheimpflug tomography system.

Expression of neurotrophic factors in human primary pterygeal tissue and selective TNF-α-induced stimulation of ciliary neurotrophic factor in pterygeal fibroblasts

Pterygium is a degenerative, fibrovascular and hyperplastic growth resulting from a proliferative tissue actively growing from altered limbal stem cells at the corneal-conjunctival junction. However, the pathogenesis of pterygium is still unclear. The aim of this study was to determine the expression of neurotrophic factors (nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), ciliary neurotrophic factor (CNTF), and neurotrophin (NT)-3, NT-4/5) in pterygeal tissue and to confirm whether tumor-necrosis factor-alpha (TNF-alpha) modulates the expression of these neurotrophic factors in primary cultured pterygeal fibroblasts. We looked for expression of these neurotrophic factors in surgically excised pterygia and normal donor limbal tissues by immunohistochemistry and in primary cultured pterygeal and normal subconjunctival Tenons fibroblasts by Western blot and reverse transcription-polymerase chain reaction (RT-PCR). Expression of CNTF and NT-4/5 is increased in pterygeal tissues compared with normal tissue, and production of CNTF is stimulated in pterygeal fibroblasts by TNF-alpha but not in normal fibroblasts. This selective stimulation of CNTF in pterygeal fibroblasts suggests that CNTF may play a role in the pathogenesis of pterygium.

Comparison of clinical outcomes between wavefront-optimized versus corneal wavefront-guided transepithelial photorefractive keratectomy for myopic astigmatism

PURPOSEnTo evaluate and compare the clinical outcomes, including visual acuity, refractive errors, and aberrations, between aberration-free transepithelial photorefractive keratectomy (PRK) and corneal wavefront-guided transepithelial PRK in eyes with myopic astigmatism.nnnSETTINGnYonsei University College of Medicine and Eyereum Eye Clinic, Seoul, South Korea.nnnDESIGNnRetrospective comparative case series.nnnMETHODSnPatients with myopic astigmatism were treated with aberration-free transepithelial PRK or corneal wavefront-guided transepithelial PRK using a 1050xa0Hz high-repetition excimer laser.xa0The safety, efficacy, predictability, and corneal aberrations were compared preoperatively and 1, 2, 3, and 6xa0months postoperatively.nnnRESULTSnThe study comprised 188 patients (188 eyes); 91 eyes had aberration-free transepithelial PRK and 97 eyes corneal wavefront-guided transepithelial PRK. Six month after surgery, the mean uncorrected distance visual acuity was comparable (-0.06 logMARxa0±xa00.07 [SD] aberration-free group; -0.06xa0±xa00.06 logMAR wavefront-guided group). The safety, efficacy, and predictability of refractive and visual outcomes were also comparable between groups. Corneal total root-mean-square (RMS) higher-order aberrations (HOAs) increased after treatment in both groups, although fewer RMS HOAs were induced in the corneal wavefront-guided group than in the aberration-free group. Spherical aberration increased similarly after treatment in both groups. However, coma and trefoil increased only in the aberration-free group.nnnCONCLUSIONSnAberration-free transepithelial PRK and corneal wavefront-guided transepithelial PRK were safe and effective for correction of myopic astigmatism without difference in visual acuity and refractive outcomes. However, the corneal wavefront-guided profile induced fewer corneal aberrations than the aberration-free profile.

Biomechanical Properties of the Cornea Measured With the Dynamic Scheimpflug Analyzer in Young Healthy Adults.

Purpose: To investigate the biomechanical properties of the cornea using the dynamic Scheimpflug analyzer in young healthy adults. Methods: This prospective cross-sectional population study included 944 eyes of 472 participants aged 20 to 40 years. Participants underwent ophthalmic investigations, including evaluation of biomechanical properties of the cornea using the dynamic Scheimpflug analyzer, manifest refraction, and measurements of keratometric values by autokeratometry, intraocular pressure (IOP) by noncontact tonometer, central corneal thickness (CCT) by ultrasound, and white-to-white distance by Scheimpflug tomography. Statistical analyses included determination of the reference interval with a bootstrapping method, linear quantile mixed-effects model, and Spearman correlation analysis between the corneal biomechanical parameters and other variables (age, manifest refraction spherical equivalent, CCT, IOP, white-to-white, and keratometric values). Results: The 90% CIs of all corneal biomechanical parameters demonstrated that the ranges of the 90% CIs for the reference data were almost identical with and without bootstrapping. Quantile regression to determine the fifth, 50th, and 95th percentiles of each corneal biomechanical parameter supported the findings from the nonparametric method with the 90% CIs. Correlation analysis showed significant correlations between the parameters and variables, but there was a relatively high Spearman correlation coefficient in the case of the correlations with the CCT and IOP. Conclusions: Using data from a large population of young healthy adults, we developed a database of normal values for multiple corneal biomechanical parameters obtained from the dynamic Scheimpflug analyzer. We conclude that the biomechanical properties of the cornea are influenced by the CCT and IOP.

Photorefractive keratectomy combined with corneal wavefront-guided and hyperaspheric ablation profiles to correct myopia.

Purpose To evaluate the effects of photorefractive keratectomy (PRK) combined with corneal wavefront–guided ablation profiles and hyperaspheric ablation profiles on changes in higher‐order aberrations (HOAs). Setting Yonsei University College of Medicine and Eyereum Clinic, Seoul, South Korea. Design Comparative observational case series. Methods Medical records of patients who had corneal wavefront–guided hyperaspheric PRK, corneal wavefront–guided mild‐aspheric PRK, or non‐corneal wavefront–guided mild‐aspheric PRK were analyzed. The logMAR uncorrected distance visual acuity (UDVA), manifest refraction spherical equivalent (MRSE), and changes in corneal aberrations (root‐mean‐square [RMS] HOAs, spherical aberration, coma) were evaluated 1, 3, and 6 months postoperatively. Results The records of 61 patients (96 eyes) were reviewed. There was no statistically significant difference in logMAR UDVA or MRSE between the 3 groups at any timepoint. Corneal RMS HOAs were significantly smaller in the corneal wavefront–guided hyperaspheric group and the corneal wavefront–guided mild‐aspheric group than in the noncorneal wavefront–guided mild‐aspheric group at each timepoint. Corneal spherical aberration was significantly smaller for corneal wavefront–guided hyperaspheric PRK than for noncorneal wavefront–guided mild‐aspheric PRK 6 months postoperatively. Changes in corneal spherical aberration (preoperatively and 6 months postoperatively) in corneal wavefront–guided hyperaspheric PRK were significantly smaller than in corneal wavefront–guided mild‐aspheric PRK (P = .046). Corneal coma was significantly smaller with corneal wavefront–guided hyperaspheric PRK and corneal wavefront–guided mild‐aspheric PRK than with noncorneal wavefront–guided mild‐aspheric PRK 3 months and 6 months postoperatively. Conclusion Corneal wavefront–guided hyperaspheric PRK induced less corneal spherical aberration 6 months postoperatively than corneal wavefront–guided mild‐aspheric PRK and noncorneal wavefront–guided mild‐aspheric PRK. Financial Disclosure None of the authors has a financial or proprietary interest in any material or method mentioned.

Comparison of Outcomes Between Combined Transepithelial Photorefractive Keratectomy With and Without Accelerated Corneal Collagen Cross-Linking: A 1-Year Study

Purpose: To investigate the effects of combined transepithelial photorefractive keratectomy (tPRK) and accelerated corneal collagen cross-linking (CXL) on visual acuity and refractive outcomes. Methods: The medical records of 89 eyes (89 patients) undergoing combined tPRK and CXL (tPRK-CXL group) or tPRK alone (tPRK group) were retrospectively analyzed. Uncorrected distance visual acuity (UDVA), corrected distance visual acuity, and manifest refraction spherical equivalent (MRSE) were evaluated preoperatively and 2 weeks, 1, 3, 6, and 12 months after surgery. Results: At 2 weeks after surgery, the tPRK-CXL group had better UDVA than the tPRK group (0.97 ± 0.22 vs. 0.85 ± 0.22, P = 0.015). At 2 weeks and 1 month after surgery, the tPRK-CXL group had a significantly lower spherical error than the tPRK group (0.24 vs. 0.63 D, P = 0.017, for 2 weeks and 0.43 vs. 0.57 D, P = 0.019, for 1 month). At 12 months after surgery, the tPRK-CXL group had a lower spherical error and MRSE than the tPRK group (0.30 vs. 0.44 D, P < 0.001, for the spherical error and 0.17 vs. 0.31 D, P < 0.001, for the MRSE). Both groups had comparable predictability, efficacy, and safety indices at 12 months after surgery. Conclusions: Combined tPRK and accelerated CXL demonstrated comparable predictability, efficacy, and safety compared with tPRK alone. Combined tPRK and CXL provides better UDVA in the early postoperative period and better refractive outcomes at 12 months postoperatively in terms of spherical error and MRSE.

Comparison of Toric Foldable Iris-Fixated Phakic Intraocular Lens Implantation and Limbal Relaxing Incisions for Moderate-to-High Myopic Astigmatism

Purpose To compare the effectiveness of toric foldable iris-fixated phakic intraocular lens (pIOL) implantation and non-toric foldable iris-fixated pIOL implantation with limbal relaxing incisions (LRIs) for correcting moderate-to-high astigmatism in myopic eyes. Materials and Methods The medical records of 146 patients (195 eyes) with myopic astigmatism who underwent toric foldable iris-fixated pIOL implantation (toric group; 94 eyes) or non-toric foldable iris-fixated pIOL implantation with concurrent LRIs (LRI group; 101 eyes) were retrospectively reviewed. For subgroup analysis, the two groups were subdivided according to preoperative astigmatic severity [moderate, 2.00 to <3.00 diopters (D); high, 3.00–4.00 D]. Visual and astigmatic outcomes were compared 6 months postoperatively. Results The uncorrected distance visual acuity was at least 20/25 in 100% and 98% of the toric and LRI group eyes, respectively. The toric group had lower mean residual cylindrical error (-0.67±0.39 D vs. -1.14±0.56 D; p<0.001) and greater mean cylindrical error change (2.17±0.56 D vs. 1.63±0.72 D; p<0.001) than the LRI group, regardless of the preoperative astigmatic severity. The mean correction index (1.10±0.16 vs. 0.72±0.24; p<0.001) and success index (0.24±0.14 vs. 0.42±0.21; p<0.001) also differed significantly between the groups. Conclusion Both surgical techniques considerably reduced astigmatism and had comparable visual outcomes. However, toric foldable iris-fixated pIOL implantation was more reliable for correcting moderate-to-high astigmatism in myopic eyes.

Biomechanical Properties of the Cornea Using a Dynamic Scheimpflug Analyzer in Healthy Eyes

Purpose To investigate biomechanical properties of the cornea using a dynamic Scheimpflug analyzer according to age. Materials and Methods In this prospective, cross-sectional, observational study, participants underwent ophthalmic investigations including corneal biomechanical properties, keratometric values, intraocular pressure (IOP), and manifest refraction spherical equivalent (MRSE). We determined the relationship of biomechanical parameters and ocular/systemic variables (participants age, MRSE, IOP, and mean keratometric values) by piecewise regression analysis, association of biomechanical parameters with variables by Spearmans correlation and stepwise multiple regression analyses, and reference intervals (RI) by the bootstrap method. Results This study included 217 eyes of 118 participants (20–81 years of age). Piecewise regression analysis between Corvis-central corneal thickness (CCT) and participants age revealed that the optimal cut-off value of age was 45 years. No clear breakpoints were detected between the corneal biomechanical parameters and MRSE, IOP, and mean keratometric values. Corneal velocity, deformation amplitude, radius, maximal concave power, Corvis-CCT, and Corvis-IOP exhibited correlations with IOP, regardless of age (all ages, 20–44 years, and over 44 years). With smaller deformation amplitude and corneal velocity as well as increased Corvis-IOP and Corvis-CCT, IOP became significantly increased. We provided the results of determination of confidence interval from RI data using bootstrap method in three separate age groups (all ages, 20–44 years, and over 44 years). Conclusion We demonstrated multiple corneal biomechanical parameters according to age, and reported that the corneal biomechanical parameters are influenced by IOP.