Biomedical subjects

Glyn Walsh

Publications and source records attributed to Glyn Walsh.

3 recordsLinked to original sources

PubMed2006

Is the spectacle lens jack-in-the-box phenomenon really due to the lenses?

The calculation of the extent of the ring scotoma around positive lenses, as conventionally taught to students of clinical optics, indicates that the scotoma is of a significant size. Using knife-edge lenses this study shows that the calculations are invalid due to the finite size of the eye's entrance pupil and in many instances the scotoma is shown not to exist. The effect noticed in clinical practice is probably largely due to the frame and the edging techniques used which add to the refractive scotoma which is present with high powered lenses, large apertures and/or small pupil sizes.

Dark Adaptation↗

PubMed2006

A simple new method for the construction of a ptosis crutch.

A technique by which a ptosis crutch can be fitted in minutes, using readily available and inexpensive materials and tools, is described. No specialist skills are needed and the device can be fitted to existing frames and lenses.

Blepharoptosis↗

PubMed2006

Materials and allergens within spectacle frames: a review.

The materials that have been reported as causing allergic contact dermatitis within spectacle frames are identified, and their most likely location on the frame is highlighted. The lack of any real control over spectacle frame quality and content is indicated to be a problem, as is the difficulty in determining the true source of many frames. Much of the information must be obtained from anonymous sources in the industry, historical 'common knowledge' of indeterminate source or reports of dermatological problems.

Allergens↗