PubMed Health⌕ Search

Biomedical subjects

G G Heath

Publications and source records attributed to G G Heath.

8 recordsLinked to original sources
PubMed1991

Reliability and validity of videokeratoscopic measurements.

When a test surface or a cornea is carefully and properly positioned with respect to the Corneal Modeling System (CMS) videokeratoscope, measurements are highly repeatable, but the accuracy of the measurements is dependent on the shape of the surface. For spherical and toroidal surfaces, the CMS provides suitably accurate descriptions of the topography of the surface. For aspheric surfaces the CMS renders less accurate, but still clinically acceptable, topographic descriptions.

Cornea↗
PubMed1991

The management of keratoconus using the corneal modeling system and a piggyback system of contact lenses.

The purpose of this report is to describe the use of the Corneal Modeling System (CMS) in the quantitative evaluation of the front surface of a soft contact lens on a keratoconic cornea. The management of one eye of a single case is presented as an example. A keratoconic patient fitted with an RGP lens presented with the signs and symptoms of discomfort, reduced wearing time and recurrent corneal erosions. Corneal topography was evaluated utilizing the CMS. The patient was then fitted with a soft contact lens. Next the entire front surface of the contact lens-fitted eye was measured with the CMS. Utilizing those data a piggyback lens was designed. As a result of this fitting technique corneal integrity improved, wearability increased and discomfort dissipated.

Adult↗
PubMed1978

Flicker effects of receptor directional sensitivity.

When a Maxwellian-view test field is alternately presented through different small areas in the pupil, a residual flicker is observed even though the luminance of the field is adjusted to compensate for the Stiles-Crawford effect. The stimulus alternation frequency that eliminated this residual flicker was used to estimate the magnitude of modulation in the receptors resulting from the difference in direction of illumination. These results support the concept that directional sensitivity of cones is much more acute than the directional sensitivity represented by conventional measures of the Stiles-Crawford effect.

Flicker Fusion↗