Publications by authors named "Byoung Jin Ha"
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 (participant's age, MRSE, IOP, and mean keratometric values) by piecewise regression analysis, association of biomechanical parameters with variables by Spearman's correlation and stepwise multiple regression analyses, and reference intervals (RI) by the bootstrap method.
Purpose: To investigate the clinical outcomes and rotational stability following implantation of V4c toric implantable collamer lenses (ICLs) (STAAR Surgical Company, Monrovia, CA) and to analyze the factors that influence rotational stability.
Methods: In this prospective observational case series, the authors analyzed the visual outcomes and rotational stability in 52 eyes of 52 patients immediately and 3 and 6 months after implantation. Postoperative rotation was defined as the angle between the adjusted axis and alignment axis.
Background: To evaluate clinical factors affecting postoperative vaulting in eyes that had achieved optimal vaulting within the range of 250-750 μm following implantation of 12.6-mm V4c implantable collamer lenses (ICL).
Methods: A total of 236 eyes of 236 patients that had achieved optimal vaulting following implantation of a 12.
Background: To investigate the effects of combined corneal wavefront-guided transepithelial photorefractive keratectomy (tPRK) and accelerated corneal collagen cross-linking (CXL) after intracorneal ring segment (ICRS) implantation in patients with moderate keratoconus.
Methods: Medical records of 23 eyes of 23 patients undergoing combined tPRK and CXL after ICRS implantation were retrospectively analyzed. Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction spherical equivalent (MRSE), corneal indices based on Scheimpflug tomography, higher-order aberrations (HOAs), and corneal biomechanical properties were evaluated before and after ICRS implantation, and at 1, 3, and 6 months after combined tPRK and CXL.
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.
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.
Background: To 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.
Methods: Medical 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.
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.
Purpose: To investigate and compare vaulting and movement changes during accommodation in eyes with the V4c and V4 implantable collamer lenses (ICL).
Design: Comparative, observational case series.
Methods: The medical records of 35 eyes (18 patients) with the V4 ICL and 51 eyes (26 patients) with the V4c ICL were retrospectively examined and included in analyses.
Purpose: To evaluate the effect of mitomycin C (MMC) on the exacerbation of corneal opacity that occurs in patients with granular corneal dystrophy type II (GCD II) after refractive corneal surface ablation.
Methods: Ten eyes of patients with GCD II who underwent refractive corneal surface ablation with MMC were compared with 10 eyes that were not treated with MMC. Best spectacle-corrected visual acuity, the degree of corneal opacity, and contrast sensitivity were evaluated at least 3 years after surgery.
Purpose: To compare the measurements of posterior corneal elevation above the best-fit sphere before and after photorefractive keratectomy (PRK) using two different technologies--Scheimpflug imaging using Pentacam (Oculus) and scanning slit combined with Placido imaging using Orbscan II (Bausch & Lomb).
Methods: In a retrospective observational case series study, 60 eyes measured using Orbscan II and Pentacam before or after PRK were evaluated. The data were analyzed as three groups: preoperative, early postoperative (from 1 to 3 months after surgery), and late postoperative (> 3 months postoperatively but not exceeding 1 year).
Purpose: To compare the accuracy of central true net corneal power (cTNP) and mean true net corneal power (mTNP) of the Pentacam system to give a keratometry (K) reading for calculating IOL (intraocular lens) power in eyes following refractive surgery.
Methods: Refraction, an automated K-reading (Km), cTNP and mTNP were measured for 15 eyes that required cataract surgery and had previously undergone refractive surgery. The difference between postoperative manifest refraction values and target refraction values calculated with the SRK/T formula using cTNP were compared with the one using mTNP.
Purpose: To report a case of inadvertent anterior chamber and cornea stromal injection with high dose antibiotics and steroids during cataract operation.
Methods: During cataract operation on a 78 year-old female patient, high dose gentamicin (20 mg/0.5 ml) and dexamethasone (2 mg/0.