Biomedical subjects

A K Lam

Publications and source records attributed to A K Lam.

8 recordsLinked to original sources

PubMed1996

Application of a modified keratometer in the study of corneal topography on Chinese subjects.

A corneal topography study was carried out on Hong Kong Chinese subjects using a modified keratometer. The Chinese corneal topography measured by this modified keratometer was similar to other studies using the Wesley-Jessen Photo Electronic Keratoscopy (PEK) System 2000. The mean p-values along the horizontal meridian and the vertical meridian were 0.82 and 0.87, respectively. A negative correlation was found between the p-value and the central corneal radius along the horizontal meridian which may indicate that a steeper central cornea will have a greater p-value. However, the correlation coefficient of 0.56 was not too certain for this conclusion to be drawn. A difference of 0.04 was found between the horizontal p-value and the vertical p-value, which may be a result of the tight lid tension along the vertical meridian. This modified keratometer can be considered as an inexpensive instrument for the study of corneal topography.

Adult↗

PubMed1995

A hand-held keratometer.

Using model eyes the sensitivity to orientation of an Alcon hand-held autokeratometer was assessed after calibration with steel balls. It was concluded that the keratometer should be used in a vertical position (6:00/12:00) in order for axis references to be accurate. Corneal curvature of optometry students was measured using the autokeratometer and a Bausch and Lomb keratometer. The results showed that the autokeratometer was similar to the Bausch and Lomb keratometer in measuring the vertical and horizontal principal meridians, and the axis of the vertical principal meridian. This hand-held keratometer is useful for screening purposes and measuring corneas of infants.

Adult↗

PubMed1994

Three month study of changes in the cornea after computer-determined and conventionally-determined contact lens fitting.

The conventional rigid-lens fitting method uses fluorescein to assess the tear layer beneath a trial lens on the corneal surface. A more advanced technique, which uses a computer program to determine the back surface specifications of a contact lens from a pre-set tear layer thickness, has been studied. No significant difference was found in terms of corneal physiological changes between the conventionally determined contact lenses and computer-determined contact lenses after a three-month wearing period. The results suggest that there is little difference in the two methods of fitting. However, the computer determined method was found to be more efficient in terms of chair time, and also can aid inexperienced rigid lens practitioners to select the appropriate lens back surface curves.

Computer-Aided Design↗

PubMed1994

Derivation of corneal flattening factor, p-value.

A mathematical equation was derived to calculate the corneal p-value based on the central and peripheral corneal radii and the corresponding semichord diameters. The calculation was simplified by a computer program written using GWBASIC. The accuracy of corneal p-value generated from this program was checked with Douthwaite's modified keratometer with good correlation. This program could be used to find out the corneal p-value and apical radius ro for any topographic keratometer which only provides central and peripheral radii without any information of the p-value and apical radius.

Anthropometry↗

PubMed1993

Rigid lens fitting made easier using a modified keratometer.

After simple modification, a keratometer can measure both the central and peripheral regions of the cornea. The apical radius and p-value of the cornea can be determined with this information using a computer program. This computer program suggests lens parameters similar to those chosen by conventional methods in rigid lens fitting. The computerized fitting method is also applicable to Chinese subjects.

Adult↗

PubMed1992

Aortic aneurysm at autopsy: a five year survey in Hong Kong.

The authors reviewed 3133 consecutive autopsies performed in the 5 year period from 1986 to 1990 in Queen Mary Hospital (Hong Kong), and 96 cases of aortic aneurysms were found. The incidence was 1 in 33 autopsies. The ratio of male to female was 1.8 to 1, and the disease was most common in the eighth decade of life. The majority of death was due to rupture (70%) or related atherosclerotic diseases (14%), and the majority of aneurysms were not suspected before autopsies (62%). Most of the non-dissecting aneurysms were found in the abdominal aorta, the infra-renal portion. For dissecting aneurysms, Daily's type A was much more common. Hypertension was recognized in a high proportion of cases. Accompanying diseases like syphilis, Takayasu's disease, ischemic heart disease, cerebrovascular accident, diabetes mellitus, peripheral vascular disease, and chronic obstructive airway disease were also noted.

Adult↗

PubMed1978

Adult onset nemaline myopathy.

A 47-year-old man had symptoms of nemaline myopathy for approximately 1 year. There were marked elevations of creatine kinase, a feature not previously described. Examination of the nervous system at autopsy failed to reveal any abnormalities.

Age Factors↗

PubMedDate not supplied

Sudden death associated with cardiac inflammatory pseudotumour.

We report a case of cardiac inflammatory pseudotumour which we believe caused sudden death in a previously healthy 55-year-old Chinese female. The features of inflammatory pseudotumours are briefly reviewed. Cardiac lesions are very rare, have only been reported in children before, and have not been associated with sudden death.

Death, Sudden↗