Publications by authors named "Antony K Law"

9 Publications

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High prevalence of myopia in children and their parents in Hong Kong Chinese Population: the Hong Kong Children Eye Study.

Acta Ophthalmol 2020 Jan 24. Epub 2020 Jan 24.

Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Kowloon, Hong Kong.

Purpose: To determine the myopia prevalence in Hong Kong Chinese children and their parents.

Methods: It was a population-based cross-sectional study. A total of 4257 children aged 6-8 years, and 5880 parents were recruited in the Hong Kong Children Eye Study. Cycloplegic autorefraction was measured for children; and non-cycloplegic autorefraction for parents. Parental educational level, children's outdoor time, and near work were collected by validated questionnaires.

Results: In children aged 6-8 years, 25.0% were myopic, and among them, 12.7% for the 6-year-olds, 24.4% for the 7-year-olds and 36.1% for the 8-year-old. About 0.7% of children aged 8 years were high myopia. In all age groups, boys (their myopia rate: 13.9% at 6 years, 26.7% at 7 years, and 38.3% at 8 years) were more myopic than girls (11.3% at 6 years, 22.0% at 7 years, 33.4% at 8 years). Among parents, 72.2% were myopic (mother, 73.2%; father, 70.7%) and 13.5% high myopia (mother, 12.8%; father, 14.5%). It was observed that prevalence decreased with ages and increased with education level.

Conclusion: There is a strikingly high prevalence of myopia in Hong Kong children aged 6-8, much higher than that of other regions of China. Of note, the prevalence of children was similar to that in 15 years ago. Furthermore, the myopia prevalence of parents is high, and it had already increased in this cohort. Prevention of childhood myopia is important, likewise for visual complications from high myopia in adults.
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http://dx.doi.org/10.1111/aos.14350DOI Listing
January 2020

Low-Concentration Atropine for Myopia Progression (LAMP) Study: A Randomized, Double-Blinded, Placebo-Controlled Trial of 0.05%, 0.025%, and 0.01% Atropine Eye Drops in Myopia Control.

Ophthalmology 2019 01 6;126(1):113-124. Epub 2018 Jul 6.

Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong.

Purpose: Low-concentration atropine is an emerging therapy for myopia progression, but its efficacy and optimal concentration remain uncertain. Our study aimed to evaluate the efficacy and safety of low-concentration atropine eye drops at 0.05%, 0.025%, and 0.01% compared with placebo over a 1-year period.

Design: Randomized, placebo-controlled, double-masked trial.

Participants: A total of 438 children aged 4 to 12 years with myopia of at least -1.0 diopter (D) and astigmatism of -2.5 D or less.

Methods: Participants were randomly assigned in a 1:1:1:1 ratio to receive 0.05%, 0.025%, and 0.01% atropine eye drops, or placebo eye drop, respectively, once nightly to both eyes for 1 year. Cycloplegic refraction, axial length (AL), accommodation amplitude, pupil diameter, and best-corrected visual acuity were measured at baseline, 2 weeks, 4 months, 8 months, and 12 months. Visual Function Questionnaire was administered at the 1-year visit.

Main Outcome Measures: Changes in spherical equivalent (SE) and AL were measured, and their differences among groups were compared using generalized estimating equation.

Results: After 1 year, the mean SE change was -0.27±0.61 D, -0.46±0.45 D, -0.59±0.61 D, and -0.81±0.53 D in the 0.05%, 0.025%, and 0.01% atropine groups, and placebo groups, respectively (P < 0.001), with a respective mean increase in AL of 0.20±0.25 mm, 0.29±0.20 mm, 0.36±0.29 mm, and 0.41±0.22 mm (P < 0.001). The accommodation amplitude was reduced by 1.98±2.82 D, 1.61±2.61 D, 0.26±3.04 D, and 0.32±2.91 D, respectively (P < 0.001). The pupil sizes under photopic and mesopic conditions were increased respectively by 1.03±1.02 mm and 0.58±0.63 mm in the 0.05% atropine group, 0.76±0.90 mm and 0.43±0.61 mm in the 0.025% atropine group, 0.49±0.80 mm and 0.23±0.46 mm in the 0.01% atropine group, and 0.13±1.07 mm and 0.02±0.55 mm in the placebo group (P < 0.001). Visual acuity and vision-related quality of life were not affected in each group.

Conclusions: The 0.05%, 0.025%, and 0.01% atropine eye drops reduced myopia progression along a concentration-dependent response. All concentrations were well tolerated without an adverse effect on vision-related quality of life. Of the 3 concentrations used, 0.05% atropine was most effective in controlling SE progression and AL elongation over a period of 1 year.
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http://dx.doi.org/10.1016/j.ophtha.2018.05.029DOI Listing
January 2019

Femtosecond Laser in situ Keratomileusis Flap Creation in Narrow Palpebral Fissure Eyes without Suction.

Case Rep Ophthalmol 2017 May-Aug;8(2):341-348. Epub 2017 Jun 6.

Department of Ophthalmology, Hong Kong Sanatorium and Hospital, Hong Kong, Hong Kong.

Purpose: To evaluate a surgical technique used in eyes with narrow palpebral fissure undergoing femtosecond laser flap creation without suction during laser in situ keratomileusis (LASIK).

Methods: All data of 2 patient groups were collected through chart review. Group 1 consisted of 6 eyes with narrow palpebral fissure in which the suction ring was manually fixated and femtosecond laser was applied accordingly. Thirty comparison cases were randomly drawn from among eyes that underwent a standard LASIK procedure matched for age and preoperative refraction (group 2). Only 1 eye of each patient was selected to compare the refractive and visual outcomes between groups.

Results: In all group 1 eyes, the flaps were created successfully with manual fixation of the suction ring without suction. No eyes lost 2 or more lines of vision. No significant difference was found in the safety and refractive outcomes between groups.

Conclusion: Manual fixation of the suction ring in eyes with narrow palpebral fissure without suction was feasible for flap creation during LASIK.
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http://dx.doi.org/10.1159/000477201DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5498974PMC
June 2017

Visual Outcomes, Quality of Vision, and Quality of Life of Diffractive Multifocal Intraocular Lens Implantation after Myopic Laser In Situ Keratomileusis: A Prospective, Observational Case Series.

J Ophthalmol 2017 4;2017:6459504. Epub 2017 Jan 4.

Department of Ophthalmology, Hong Kong Sanatorium and Hospital, Hong Kong.

. To report visual performance and quality of life after implantation of a bifocal diffractive multifocal intraocular lens (MIOL) in postmyopic laser in situ keratomileusis (LASIK) patients. . Prospective, observational case series. Patients with prior myopic LASIK who had implantation of Tecnis ZMA00/ZMB00 MIOL (Abbott Medical Optics) at Hong Kong Sanatorium and Hospital were included. Postoperative examinations included monocular and binocular distance, intermediate and near visual acuity (VA), and contrast sensitivity; visual symptoms (0-5); satisfaction (1-5); spectacle independence rate; and quality of life. . Twenty-three patients (27 eyes) were included. No intraoperative complications developed. Mean monocular uncorrected VA at distance, intermediate, and near were 0.13 ± 0.15 (standard deviation), 0.22 ± 0.15, and 0.16 ± 0.15, respectively. Corresponding mean values for binocular uncorrected VA were 0.00 ± 0.10, 0.08 ± 0.13, and 0.13 ± 0.10, respectively. No eyes lost >1 line of corrected distance VA. Contrast sensitivity at different spatial frequencies between operated and unoperated eyes did not differ significantly (all > 0.05). Mean score for halos, night glare, starbursts, and satisfaction were 1.46 ± 1.62, 1.85 ± 1.69, 0.78 ± 1.31, and 3.50 ± 1.02, respectively. Eighteen patients (78%) reported complete spectacle independence. Mean composite score of the quality-of-life questionnaire was 90.31 ± 8.50 out of 100. . Implantation of the MIOL after myopic LASIK was safe and achieved good visual performance.
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http://dx.doi.org/10.1155/2017/6459504DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5241461PMC
January 2017

Cataract Surgery with a New Fluidics Control Phacoemulsification System in Nanophthalmic Eyes.

Case Rep Ophthalmol 2016 Sep-Dec;7(3):218-226. Epub 2016 Oct 21.

Department of Ophthalmology, Hong Kong Sanatorium and Hospital, Hong Kong, Hong Kong.

Purpose: To report visual outcomes and complications after cataract surgery in nanophthalmic eyes with a phacoemulsification system using the active fluidics control strategy.

Methods: This is a retrospective case series. All eyes with an axial length of less than 20 mm that underwent cataract surgery or refractive lens exchange using the Centurion Vision System (Alcon Laboratories Inc.) in Hong Kong Sanatorium and Hospital were evaluated. The visual acuity and intraoperative and postoperative complications were reported. Prior approval from the Hospital Research Committee has been granted.

Results: Five eyes of 3 patients were included. The mean follow-up period was 10.2 ± 5.3 months (range, 4-18). Two eyes (40%) had a one-line loss of corrected distance visual acuity. No uveal effusion and posterior capsular tear developed. An optic crack and haptic breakage in the intraocular lens developed in 1 eye (20%) and 2 eyes (40%), respectively. Additional surgeries to treat high postoperative intraocular pressure were required in 1 eye (20%).

Conclusion: The use of a new phacoemulsification system, which actively monitors and maintains the intraoperative pressure, facilitated anterior chamber stability during cataract surgery in nanophthalmic eyes. This minimized the risk of major complications related to unstable anterior chambers such as uveal effusion and posterior capsular tear. Development of intraoperative crack/breakage in a high-power intraocular lens was common.
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http://dx.doi.org/10.1159/000452158DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5121556PMC
October 2016

Visual Performance after Bilateral Implantation of a Four-Haptic Diffractive Toric Multifocal Intraocular Lens in High Myopes.

J Ophthalmol 2016 2;2016:5320105. Epub 2016 Aug 2.

Department of Ophthalmology, Hong Kong Sanatorium and Hospital, 8/F, Li Shu Pui Block, Phase II, 2 Village Road, Happy Valley, Hong Kong.

Background. The vision with diffractive toric multifocal intraocular lenses after cataract surgery in long eyes has not been studied previously. Objectives. To report visual performance after bilateral implantation of a diffractive toric multifocal intraocular lens in high myopes. Methods. Prospective, observational case series to include patients with axial length of ≥26 mm and corneal astigmatism of >1 dioptre who underwent bilateral AT LISA 909M implantation. Postoperative examinations included photopic and mesopic distance, intermediate, and near visual acuity; photopic contrast sensitivity; visual symptoms (0-5); satisfaction (1-5); and spectacle independence rate. Results. Twenty-eight eyes (14 patients) were included. Postoperatively, mean photopic monocular uncorrected distance, intermediate, and near visual acuities (logMAR) were 0.12 ± 0.20 (standard deviation), 0.24 ± 0.16, and 0.29 ± 0.21, respectively. Corresponding binocular values were -0.01 ± 0.14, 0.13 ± 0.12, and 0.20 ± 0.19, respectively. One eye (4%) had one-line loss in vision. Under mesopic condition, intermediate vision and near vision decreased significantly (all P ≤ 0.001). Contrast sensitivity at all spatial frequencies did not improve significantly under binocular condition (all P > 0.05). Median scores for halos, night glare, starbursts, and satisfaction were 0.50, 0.00, 0.00, and 4.25, respectively. Ten patients (71%) reported complete spectacle independence. Conclusions. Bilateral implantation of the intraocular lens in high myopes appeared to be safe and achieved good visual performance and high satisfaction.
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http://dx.doi.org/10.1155/2016/5320105DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4985582PMC
August 2016

Comparison of refractive and visual outcomes with centration points 80% and 100% from pupil center toward the coaxially sighted corneal light reflex.

J Cataract Refract Surg 2016 Mar;42(3):412-9

From the Department of Ophthalmology, Hong Kong Sanatorium and Hospital, Hong Kong Special Administration Region, China.

Purpose: To compare the refractive and visual outcomes between 2 ablation centration points, 80% and 100% from the pupil center toward the coaxially sighted corneal light reflex.

Setting: Hong Kong Sanatorium and Hospital, Hong Kong, China.

Design: Retrospective comparative study.

Methods: All eyes had myopic laser in situ keratomileusis with the ablation 80% or 100% from the pupil center toward the coaxially sighted corneal light reflex. Three months postoperatively, the refractive and visual outcomes were compared between groups. Subgroup analysis was also performed for the large-angle κ and small-angle κ groups.

Results: There were no differences in the preoperative variables between groups. Three months postoperatively, the sphere was significantly more hyperopic in the 80% group than in the 100% group (0.19 diopter [D] versus 0.09 D) (P = .009) and the cylinder was significantly lower in the 80% group (0.25 D versus 0.33 D) (P = .011). More eyes achieved zero astigmatism in the 80% group than in the 100% group (43.9% versus 34.2%), and fewer eyes had astigmatism greater than 0.75 D in the 80% group (0.9% versus 6.1%) (P = .039). The error from the target refraction indicated that the 80% group tended to have significantly less undercorrection (P = .045). There were no significant differences in the other outcomes. Subgroup analysis did not show significant findings for the large-angle κ.

Conclusions: Both 80% centration and 100% centration were safe and effective. Compared with the 100% group, the 80% group had less astigmatism and less undercorrection.
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http://dx.doi.org/10.1016/j.jcrs.2015.09.030DOI Listing
March 2016

Visual outcomes and patient satisfaction after refractive lens exchange with a single-piece diffractive multifocal intraocular lens.

J Ophthalmol 2014 23;2014:458296. Epub 2014 Nov 23.

Department of Ophthalmology, Hong Kong Sanatorium and Hospital, 8/F, Li Shu Pui Block, Phase II, 2 Village Road, Happy Valley, Hong Kong.

Purpose. To report visual outcomes and patient satisfaction after unilateral or bilateral refractive lens exchange (RLE) with a single-piece bifocal diffractive multifocal intraocular lens (MIOL). Methods. All patients underwent RLE with the ZMB00 MIOL (Abbott Medical Optics). Patient charts were reviewed to evaluate the distance, intermediate, and near visual acuity (VA), contrast sensitivity, extent of visual symptoms (0-5), satisfaction (1-5), and rate of spectacle independence between unilateral and bilateral RLE group. Results. Forty-seven eyes of 28 patients were included. No intraoperative complications developed. Mean monocular uncorrected VA at distance, intermediate (67 cm), and near (30 cm) were 0.01 ± 0.12 (standard deviation), 0.27 ± 0.18, and 0.15 ± 0.11, respectively. No eyes lost >1 line of corrected distance VA. Monocular contrast sensitivity remained at normal level. Median scores of halos, night glare, and starbursts for 27 patients were 2.0, 3.0, and 0.0, respectively. Median score of satisfaction was 4.0. There were no differences in visual symptom scores or satisfaction between unilateral and bilateral group (P > 0.05). Eighty percent of 25 patients reported total spectacle freedom, with similar rate between bilateral (82%) and unilateral group (75%) (P = 1.000). Conclusions. RLE with the bifocal diffractive MIOL was safe in presbyopic patients and resulted in a high rate of spectacle independence.
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http://dx.doi.org/10.1155/2014/458296DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4258327PMC
December 2014

Initial evaluation of a femtosecond laser system in cataract surgery.

J Cataract Refract Surg 2014 Jan 22;40(1):29-36. Epub 2013 Nov 22.

From the Department of Ophthalmology, Hong Kong Sanatorium and Hospital, Hong Kong Special Administrative Region, China.

Purpose: To report the early experience and complications during cataract surgery with a noncontact femtosecond laser system.

Setting: Hong Kong Sanatorium and Hospital, Hong Kong Special Administrative Region, China.

Design: Retrospective case series.

Methods: All patients had anterior capsulotomy or combined anterior capsulotomy and lens fragmentation using a noncontact femtosecond laser system (Lensar) before phacoemulsification. Chart and video reviews were performed retrospectively to determine the intraoperative complication rate. Risk factors associated with the complications were also analyzed.

Results: One hundred seventy eyes were included. Free-floating capsule buttons were found in 151 eyes (88.8%). No suction break occurred in any case. Radial anterior capsule tears occurred in 9 eyes (5.3%); they did not extend to the equator or posterior capsule. One eye (0.6%) had a posterior capsule tear. No capsular block syndrome developed, and no nuclei were dropped during irrigation/aspiration (I/A). Anterior capsule tags and miosis occurred in 4 eyes (2.4%) and 17 eyes (10.0%), respectively. Different severities of subconjunctival hemorrhages developed in 71 (43.8%) of 162 eyes after the laser procedure. The mean surgical time from the beginning to the end of suction was 6.72 minutes ± 4.57 (SD) (range 2 to 28 minutes).

Conclusions: Cataract surgery with the noncontact femtosecond laser system was safe. No eye lost vision because of complications. Caution should be taken during phacoemulsification and I/A to avoid radial anterior capsule tears and posterior capsule tears.
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http://dx.doi.org/10.1016/j.jcrs.2013.08.045DOI Listing
January 2014