Publications by authors named "Han-Bor Fam"
Objectives: This comparative study aimed to determine if total keratometry (TK) from IOLMaster 700 could be applied to conventional formulas to perform IOL power calculation in eyes with previous myopic laser refractive surgery, and to evaluate their accuracy with known post-laser refractive surgery formulas.
Methods: Sixty-four eyes of 49 patients with previous myopic laser refractive surgery were evaluated 1 month after cataract surgery. A comparison of the prediction error was made between no clinical history post-laser refractive surgery formulas (Barrett True-K, Haigis-L, Shammas-PL) and conventional formulas (EVO, Haigis, Hoffer Q, Holladay I, and SRK/T) using TK values obtained with the optical biometer IOLMaster 700 (Carl Zeiss Meditec), as well as Barrett True-K with TK.
Purpose: To assess the corneal keratometric values obtained using the VERION image-guided surgery system and other devices.
Methods: This study evaluated the right eyes of 115 cataract patients before intraocular lens (IOL) implantation through consecutive tests using 5 devices: VERION Reference Unit, Placido-based corneal topography (OPD-Scan III), monochromatic light-emitting diodes (LenStar LS900 and AL-Scan), and rotary prism technology (auto kerato-refractometer KR-8800). Analyzed parameters were corneal steep and flat keratometric values (Ks and Kf) and corneal astigmatism and axis.
Aims: To determine the analgesic effect of supplemental intracameral lidocaine 1% during phacoemulsification under topical anaesthesia, and to assess the risk factors associated with pain.
Methods: In a double-masked, randomised, clinical trial, 506 patients undergoing phacoemulsification under topical anaesthesia were randomised to receive a supplemental intracameral injection of either 0.5 cc of 1% lidocaine (277 patients, 54.
Ethnic differences in higher-order aberrations: Spherical aberration in the South East Asian Chinese eye.
J Cataract Refract Surg
December 2009
Purpose: To determine the distribution of higher-order corneal and ocular aberrations in a healthy refractive surgery population.
Setting: Island Hospital, Penang, Malaysia.
Methods: In this prospective observational study, 1 eye of ethnic Chinese refractive surgery patients was evaluated with an Orbscan II corneal topographer and a Zywave Hartmann-Shack aberrometer with a 6.
Purpose: To estimate the posterior corneal power for intraocular lens (IOL) calculation after myopic LASIK.
Methods: A retrospective study of 50 patients (92 eyes) who underwent uneventful myopic LASIK was conducted. Pre- and postoperative data (12 months) were collected including refraction and Orbscan II (Bausch & Lomb) for simulated keratometry (Sim K), central corneal thickness, and posterior corneal power.
Purpose: To compare the accuracy and predictability of different intraocular lens (IOL) power calculation methods in eyes after myopic excimer laser surgery.
Methods: Phacoemulsification and IOL implantation outcomes in 37 eyes of 37 patients with prior LASIK or photorefractive keratectomy were documented (amount of correction=-6.92+/-3.
Meridional analysis for calculating the expected spherocylindrical refraction in eyes with toric intraocular lenses.
J Cataract Refract Surg
December 2007
Purpose: To present a method of calculating the expected spherocylindrical refraction after toric intraocular lens (IOL) implantation and to compare it with the actual outcomes in a small group of patients.
Setting: Eye Institute, Tan Tock Seng Hospital, Singapore.
Methods: The expected refractions of the 2 principal meridians of the cornea (maximum keratometry and minimum keratometry) were calculated separately using the Holladay 1 formula with a modification to the data used for the effective lens position.
Validity of the keratometric index: large population-based study.
J Cataract Refract Surg
April 2007
Purpose: To determine the accuracy of the keratometric index of 1.3315 based on the Gullstrand model eye in predicting the power of the posterior cornea, Gullstrand's model was compared to a calculated keratometric index derived from actual measurements of the cornea.
Setting: Eye Institute, Tan Tock Seng Hospital, Singapore.
Relationship between the corneal surface and the anterior segment of the cornea: An Asian perspective.
J Cataract Refract Surg
November 2006
Purpose: To determine the values for the anterior best-fit sphere (BFS) and posterior BFS in an Asian population using the Orbscan II (Bausch & Lomb) slit-scanning Placido disk corneal topographer.
Setting: Hospital-based refractive surgery center.
Methods: This prospective nonrandomized study comprised of 1 eye of 724 subjects.
Introduction: The aim of the study was to compare the visual performance of LASIK eyes measured using high-contrast logMAR letter charts under bright (photopic) and dim (mesopic) conditions.
Materials And Methods: A total of 46 subjects (35 +/- 8 years of age) undergoing LASIK procedures were recruited for the study. The best spectacle-corrected visual acuity (BSCVA) of each subject was measured using the high-contrast ETDRS logMAR chart under photopic and mesopic conditions at 3 visits: preoperative (Pre), 1 month postoperative (Post1) and 3 months postoperative (Post3).
Purpose: To determine an index that distinguishes keratoconus and keratoconus-suspect eyes from normal eyes with Orbscan (Bausch & Lomb) corneal elevation maps.
Setting: Department of Ophthalmology, Tan Tock Seng Hospital, Singapore, and iLaser Centre, Island Hospital, Penang, Malaysia.
Methods: In this initial phase of this multicenter nonrandomized retrospective study, 1 eye of 166 normal subjects, 15 keratoconus patients, and 11 keratoconus suspects was examined at 1 clinic.
Purpose: To evaluate a novel non-surgical method for improving vision in a refractive surgery patient.
Methods: A 45-year-old man who had undergone LASIK 5 years previously presented with blurred distance vision. Unaided vision in the right eye was 20/329-2) and 20/20 in the left eye.
Purpose: The Orbscan II is a hybrid slit-scanning and Placido disc corneal topographer capable mapping global pachymetry over a 10-mm corneal diameter. In this study, the repeatability of the Orbscan global pachymetry was determined.
Methods: Five consecutive Orbscan examinations were performed on one eye of 20 healthy volunteers by one examiner in one session.
Background: We report the complications and management of a retained bee sting injury to the cornea. The case highlights the acute and chronic management of an uncommon injury and its pathogenesis.
Methods: A 67-year-old man was attacked by a swarm of bees and was referred for severe chemosis on the right eye.
Bilateral laser in situ keratomileusis was performed in a 37-year-old male ethnic Chinese adventurer. Eight weeks postoperatively, the patient made an unassisted trek to the geographic North Pole. After 2 weeks in this environment, a myopic shift of more than -1.
View Article and Find Full Text PDFPurpose: To determine the effect of individual Zernike wavefront aberrations on binocular summation and binocular visual acuity.
Methods: A 0.25-microm wavefront aberration of second, third and fourth order Zernike modes were introduced into a set of log minimum angle of resolution unit (logMAR) visual acuity charts convolved by CTView.
Evaluation of biofilm formation on nylon sutures removed from clinically noninfected eyes after cataract surgery.
J Cataract Refract Surg
September 2004
Purpose: To determine the presence of bacterial biofilm on nylon sutures removed from clinically noninfected eyes after cataract surgery.
Setting: The Eye Institute, Tan Tock Seng Hospital, Singapore, Singapore.
Methods: Sutures were removed from 10 eyes after cataract surgery at different time periods.