Helping You Find Full Text Journal Articles

Search Results:

Author: George C Woo (24)



View Full Text PDF Listings View primary source full text article PDFs.

Sep
2014

Stroke, a common cerebrovascular accident, usually results in various extents of functional disability. Extensive studies have shown that ocular and visual problems are common in patients with stroke. Unfortunately, current stroke rehabilitation programs rarely address stroke-related ocular and visual problems in Hong Kong.

View Full Text PDF Listings View primary source full text article PDFs.

Mar
2014

Myopia is a significant public health problem, making it important to determine whether a bifocal spectacle treatment involving near prism slows myopia progression in children.
To determine whether bifocal and prismatic bifocal spectacles control myopia in children with high rates of myopia progression and to assess whether the treatment effect is dependent on the lag of accommodation and/or near phoria status.
This 3-year randomized clinical trial was conducted in a private practice.

View Full Text PDF Listings View primary source full text article PDFs.


View Full Text PDF Listings View primary source full text article PDFs.

Jun
2011

This study had three main goals: to assess the degree of suppression in patients with strabismic, anisometropic, and mixed amblyopia; to establish the relationship between suppression and the degree of amblyopia; and to compare the degree of suppression across the clinical subgroups within the sample.
Using both standard measures of suppression (Bagolini lenses and neutral density [ND] filters, Worth 4-Dot test) and a new approach involving the measurement of dichoptic motion thresholds under conditions of variable interocular contrast, the degree of suppression in 43 amblyopic patients with strabismus, anisometropia, or a combination of both was quantified.
There was good agreement between the quantitative measures of suppression made with the new dichoptic motion threshold technique and measurements made with standard clinical techniques (Bagolini lenses and ND filters, Worth 4-Dot test).

View Full Text PDF Listings View primary source full text article PDFs.

Feb
2011

Type 2 Diabetes Mellitus (DM) is increasing worldwide and affects ∼11% of the Hong Kong population. Diabetic retinopathy (DR) is a common cause of vision loss in type 2 DM. Risk of DR is increased by poor glycemic control, elevated lipids, and blood pressure, but it is not possible to predict the development or progression of DR at an individual level.

View Full Text PDF Listings View primary source full text article PDFs.

Jan
2011

Bifocal spectacle lenses have been used as a strategy to slow myopic progression in children since the 1950s and perhaps earlier. The reported success of this strategy varies greatly, as does the design of studies reporting the outcomes of their use-from earlier retrospective analysis of records to later prospective clinical trials. Collectively, published data support the suggestion that bifocal lenses inhibit myopic development in children but only by a small amount and only in a subset of children.

View Full Text PDF Listings View primary source full text article PDFs.

Sep
2010

This study aims to determine the factors affecting the accuracy in the Developmental Eye Movement (DEM) test measurement for Cantonese-speaking children.
The voices of 10 Cantonese-speaking children (aged between six and eight years) undertaking the vertical test (40 numbers) of the DEM test were recorded on a digital audio recorder. These voice clips were assessed by an experienced examiner to give the DEM test times.

View Full Text PDF Listings View primary source full text article PDFs.

Dec
2010

Although eye dominance assessment is used to assist clinical decision-making, current understanding is limited by inconsistencies across the range of available tests. A new psychophysical test of sensory eye dominance has been developed that objectively measures the relative contribution of each eye to a fused suprathreshold binocular percept.
Six standard tests and the newly developed test were used to measure motor and sensory dominance in a group of 44 binocularly normal individuals (mean age, 29.

View Full Text PDF Listings View primary source full text article PDFs.

Jul
2010

There is no published norm for the Developmental Eye Movement (DEM) Test for Cantonese-speaking Chinese children. This study aimed to determine the normative values of this test for Cantonese-speaking Chinese children in Hong Kong SAR and to compare the results with the published norms of English-speaking and Spanish-speaking children.
Cantonese-speaking students aged from 6 to 11 years were tested by the DEM test in Cantonese and a digital recorder was used to record the process.

View Full Text PDF Listings View primary source full text article PDFs.

Jan
2010

To determine whether bifocal and prismatic bifocal spectacles could control myopia in children with high rates of myopic progression.
This was a randomized controlled clinical trial. One hundred thirty-five (73 girls and 62 boys) myopic Chinese Canadian children (myopia of > or =1.

View Full Text PDF Listings View primary source full text article PDFs.

Jan
2009

Thyroid disease induced diplopia.

Clin Exp Optom 2009 Jan 10;92(1):30-3. Epub 2008 Jul 10.
Kwai Mei Law, George C Woo
This report describes a patient who was suffering from incomitant vertical diplopia due to Graves' ophthalmopathy. Previous optical treatment was a diffusing lens for the left eye resulting in monocular vision only. We proceeded to measure the amount of diplopia and prescribed a vertical Fresnel prism to be placed on the left spectacle lens to alleviate his diplopia and resolve his mobility problems.

View Full Text PDF Listings View primary source full text article PDFs.

View Full Text PDF Listings View primary source full text article PDFs.

May
2007

To evaluate the refractive error and visual acuity (VA) at various contrast levels in the two eyes of overnight orthokeratology (ortho-k) subjects, and to compare their postortho-k VA with the best corrected VA of spectacle-wearing control subjects matched for age, gender, and initial refractive error.
Distance postortho-k uncorrected and best corrected logMAR VA at four different contrast levels of 31 ortho-k (test) subjects (aged 7-35 years old) and the best corrected VA of 31 spectacle-wearing (control) subjects were measured and compared using the Waterloo Four-Contrast LogMAR VA Chart, which incorporated four sets of letters at different contrast levels: 90%, 48%, 21%, and 7%. Noncycloplegic manifest refractive error was measured in both eyes.

View Full Text PDF Listings View primary source full text article PDFs.

Jan
2007

The high prevalence of myopia in Chinese children living in urban East Asian countries such as Hong Kong, Taiwan, and China has been well documented. However, it is not clear whether the prevalence of myopia would be similarly high for this group of children if they were living in a Western country. This study aims to determine the prevalence and progression of myopia in ethnic Chinese children living in Canada.

View Full Text PDF Listings View primary source full text article PDFs.

Nov
2005

The development of optometric education and the establishment of formal tertiary educational programs in the Chinese mainland, Hong Kong and Taiwan are described. The various types of degree and diploma programs from medical and technological universities are differentiated. The definition of optometry, as it is understood by the regulatory bodies and the populace, is discussed.

View Full Text PDF Listings View primary source full text article PDFs.

Sep
2004

To investigate the repeatability of logMAR visual acuity (VA) with the Waterloo Four-Contrast LogMAR Visual Acuity (FCLVA) chart and the Near Vision Test (NVT) card. The differences and agreements between near logMAR VA using horizontally- and vertically-presented letters were also determined.
Visual acuity of one eye (55 subjects) was first assessed by using the FCLVA chart, comprising four charts of varying contrast, and then with the NVT card (comprising four charts of two contrasts and two presentations).

View Full Text PDF Listings View primary source full text article PDFs.

Jan
2003

To develop, evaluate, and use an objective method to determine the effect of laser in situ keratomileusis (LASIK) on corneal clarity.
Centre for Myopia Research, The Hong Kong Polytechnic University, and the Hong Kong Laser Eye Center, Hong Kong, China.
Color photographs of corneal sections were taken using a digital camera and converted to 8-bit gray-scale images.

View Full Text PDF Listings View primary source full text article PDFs.

Nov
2002

Anterior chamber configuration can be assessed via optical or ultrasonic techniques. Scheimpflug photography is a non-invasive method measuring the anterior segment. The Anterior Eye Segment analysis system, EAS-1000, utilises the Scheimpflug principle and was found to have good repeatability.

View Full Text PDF Listings View primary source full text article PDFs.

Nov
2002

It is known that the macular pigment can significantly affect colour matching and other aspects of colour vision tests. The difference in macular pigmentation between Asians and Caucasians may lead to different colour discrimination.
This study compared chromatic discrimination between Asians and Caucasians using the Farnsworth-Munsell 100 Hue test.

View Full Text PDF Listings View primary source full text article PDFs.

Oct
2002

To determine whether contrast sensitivity measurement, a more sensitive test of visual function than visual acuity, better characterizes visual outcomes after laser in situ keratomileusis (LASIK).
Hong Kong Laser Eye Centre, Hong Kong, China.
Contrast sensitivity was monitored in 41 LASIK patients for 1 year.

View Full Text PDF Listings View primary source full text article PDFs.

May
2001

In 1984, Kozlowski, Mainster and Avila derived a formula for the power of the lens needed in the negative lens field expander. Their method is based on the principle of telescopic magnification. In this technical note, we use the principle of spectacle magnification and obtain the power of the same lens.

View Full Text PDF Listings View primary source full text article PDFs.

May
2001

BACKGROUND: The main optical effect of an ophthalmic prism is to deviate uniformly the entire field of view seen through the prism, resulting in an equal eye movement, if fixation on the same object is to be maintained. Conversely, it has been suggested that, in the case of low vision due to central scotoma, the eye changes its eccentric viewing behaviour when a prism is introduced, that is, the eye remains stationary with a change of retinal image location. METHOD: A new method is described in which retinal image position was recorded with a confocal scanning laser ophthalmoscope in four experimental conditions.

View Full Text PDF Listings View primary source full text article PDFs.

May
2001

The term magnification.

Clin Exp Optom 2001 May;84(3):113-119
George C Woo, Andrew Mah-Leung
Many types of magnification described by different authors have dissimilar meanings. Basic principles of magnification such as relative size magnification, relative distance magnification and angular magnification used commonly in low vision are clarified in this paper. The three frequently-used terms of magnification, including apparent magnification, two relative magnification formulae, namely, M = F/4 and M = F/2.

View Full Text PDF Listings View primary source full text article PDFs.

Back to top