CHI HO TO

Prof. CHI HO TO


Research Focus & Metrics

Academic Career Length

29Years (1998-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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29 October 2013 in British Journal of Ophthalmology
Verified
Journal Article
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Carly Siu Yin LamCarly Siu Yin Lam
Carly Siu Yin Lam
WTWing Chun Tang
Wing Chun Tang
DTDennis yan-yin Tse
Dennis yan-yin Tse
YTYing Yung Tang
Ying Yung Tang
CTCHI HO TO
CHI HO TO
Aims To determine if ‘Defocus Incorporated Soft Contact’ (DISC) lens wear slows childhood myopia progression. Methods A 2-year double-blind randomised controlled trial was carried out in 221 children aged 8–13 years, with myopia between −1.00 and −5.00 Dioptres (D) and astigmatism ≤1.00 D. Subjects were randomly assigned to the DISC (n=111) or single vision (SV; n=110) contact lens group. DISC lenses incorporated concentric rings, which provided an addition of +2.50 D, alternating with the normal distance correction. Refractive error (cycloplegic autorefraction) and axial length were measured at 6-month intervals. Differences between groups were analysed using unpaired t test. Results In total, 128 children completed the study, n=65 in the DISC group and n=63 in the SV group. Myopia progressed 25% more slowly for children in the DISC group compared with those in the control group (0.30 D/year; 95% CI −0.71 to −0.47 vs 0.4 D/year; 95% CI −0.93 to −0.65, p=0.031). Likewise, there was less axial elongation for children in the DISC versus SV groups (0.13 mm/year; 95% CI 0.20 to 0.31 vs 0.18 mm/year; 95% CI 0.30 to 0.43, p=0.009). Treatment effect correlated positively with DISC lens wearing time (r=0.342; p=0.005). Indeed, myopia in children who wore the DISC lenses for five or more hours/day progressed 46% (mean difference=−0.382 D, p=0.001; 95% CI −0.59 to −0.17) less than those in the SV group. Conclusions The daily wearing of DISC lens significantly slowed myopia progression and axial elongation in Hong Kong schoolchildren. The findings demonstrated that simultaneous clear vision with constant myopic defocus can retard myopia progression.

18 August 2016 in PLOS ONE
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DWDanyang Wang
Danyang Wang
RCRachel Ka-Man Chun
Rachel Ka-Man Chun
MLManli Liu
Manli Liu
RLRoger Pak Kin Lee
Roger Pak Kin Lee
YSYuan Sun
Yuan Sun
CTCHI HO TO
CHI HO TO
The current study aimed to examine the short-term choroidal response to optical defocus in schoolchildren. Myopic schoolchildren aged 8–16 were randomly allocated to control group (CG), myopic defocus group (MDG) and hyperopic defocus group (HDG) (n = 17 per group). Children in MDG and HDG received additional +3D and -3D lenses, respectively, to their full corrections on the right eyes. Full correction was given to their left eyes, and on both eyes in the CG. Axial length (AXL) and subfoveal choroidal thickness (SFChT) were then measured by spectral domain optical coherence tomography. Children wore their group-specific correction for 2 hours after which any existing optical defocus was removed, and subjects wore full corrections for another 2 hours. Both the AXL and SFChT were recorded hourly for 4 hours. The mean refraction of all subjects was -3.41 ± 0.37D (± SEM). SFChT thinned when exposed to hyperopic defocus for 2 hours but less thinning was observed in response to myopic defocus compared to the control group (p < 0.05, two-way ANOVA). Removal of optical defocus significantly decreased SFChT in the MDG and significantly increased SFChT in the HDG after 1 and 2 hours (mean percentage change at 2-hour; control vs. hyperopic defocus vs. myopic defocus; -0.33 ± 0.59% vs. 3.04 ± 0.60% vs. -1.34 ± 0.74%, p < 0.01). Our results showed short-term exposure to myopic defocus induced relative choroidal thickening while hyperopic defocus led to choroidal thinning in children. This rapid and reversible choroidal response may be an important clinical parameter in gauging retinal response to optical defocus in human myopia.

1 October 2014 in Journal of Refractive Surgery
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Journal Article
Closed access
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DWDanyang Wang
Danyang Wang
MLManli Liu
Manli Liu
YCYile Chen
Yile Chen
XZXiaoying Zhang
Xiaoying Zhang
YXYangtao Xu
Yangtao Xu
QLQuan Liu
Quan Liu
PURPOSE: To compare the corneal biomechanical properties before and after small incision lenticule extraction (SMILE) and femtosecond laser-assisted LASIK in different levels of myopia with the Ocular Response Analyzer (Reichert Ophthalmic Instruments, Depew, NY). METHODS: A total of 187 and 79 eyes that received SMILE or LASIK, respectively, between January and June 2013 at Zhongshan Ophthalmic Center were enrolled in this study. Patients were grouped according to surgery type (SMILE or LASIK) and −6.00 diopters (D) or less (⩽ −6.00 D) or myopia greater than −6.00 D (>−6.00 D). Corneal hysteresis, corneal resistance factor, and 37 waveform parameters were recorded and compared preoperatively and at 1 week and 1 and 3 months postoperatively. RESULTS: There was a significant decrease of corneal hysteresis, corneal resistance factor, p1area, and p2area, and an increase of path1 and path2 in both SMILE and LASIK. In myopia −6.00 D or less, the differences between SMILE and LASIK were not significant ( P > .05), but in myopia greater than −6.00 D, the corneal hysteresis, corneal resistance factor, p1area, and p2area decreased significantly more in LASIK than in SMILE ( P < .05). CONCLUSIONS: When comparing SMILE with LASIK, myopia was greater than −6.00 D, and the corneal hysteresis, corneal resistance factor, p1area, and p2area decrease was less after SMILE. [ J Refract Surg . 2014;30(10):702–707.]

1 January 2021 in Oxidative Medicine and Cellular Longevity
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Journal Article
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LPLi Pan
Li Pan
KCKinsang Cho
Kinsang Cho
IYIrvin Yi
Irvin Yi
CTCHI HO TO
CHI HO TO
DCDong Chen
Dong Chen
CDChi Wai Do
Chi Wai Do
Ischemia is a common pathological condition present in many neurodegenerative diseases, including ischemic stroke, retinal vascular occlusion, diabetic retinopathy, and glaucoma, threatening the sight and lives of millions of people globally. Ischemia can trigger excessive oxidative stress, inflammation, and vascular dysfunction, leading to the disruption of tissue homeostasis and, ultimately, cell death. Current therapies are very limited and have a narrow time window for effective treatment. Thus, there is an urgent need to develop more effective therapeutic options for ischemia‐induced neural injuries. With emerging reports on the pharmacological properties of natural flavonoids, these compounds present potent antioxidative, anti‐inflammatory, and antiapoptotic agents for the treatment of ischemic insults. Three major active flavonoids, baicalein, baicalin, and wogonin, have been extracted from Scutellaria baicalensis Georgi (S. baicalensis); all of which are reported to have low cytotoxicity. They have been demonstrated to exert promising pharmacological capabilities in preventing cell and tissue damage. This review focuses on the therapeutic potentials of these flavonoids against ischemia‐induced neurotoxicity and damage in the brain and retina. The bioactivity and bioavailability of baicalein, baicalin, and wogonin are also discussed. It is with hope that the therapeutic potential of these flavonoids can be utilized and developed as natural treatments for ischemia‐induced injuries of the central nervous system (CNS).

1 September 1999 in Journal of Pineal Research
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Journal Article
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ASAndrew W. Siu
Andrew W. Siu
RRRussel J. Reiter
Russel J. Reiter
CTCHI HO TO
CHI HO TO

1 October 2014 in Journal of Ocular Pharmacology and Therapeutics
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Journal Article
Closed access
JXJing-Ru Xiao
Jing-Ru Xiao
CDChi Wai Do
Chi Wai Do
CTCHI HO TO
CHI HO TO
Ocular diseases such as cataract, glaucoma, age-related macular degeneration (AMD), and diabetic retinopathy are the leading causes of blindness. The elderly population is at particular risk of developing one or more of these age-related ocular diseases. By virtue of multiple bioactivities, effort has been made to develop dietary flavonoids as complimentary therapies for ocular disorders. Dietary intake of flavonoids has been reported to reduce the risk of cataract and AMD. This review focuses on the main flavones baicalein, baicalin, and wogonin isolated from the Chinese medicinal herb, Scutellariae radix (SR), which has been widely used in Asian countries for the treatment of many diseases. Interest in SR has grown recently following new findings that suggest multiple routes of therapeutic action. This review will summarize the diverse pharmacological properties, therapeutic roles, and mechanisms of these flavones of SR in cellular and animal models of ocular diseases.