Tubular Spectacles

Coloured Spectacles

British Standards for Spectacles.

EARLIER articles have reviewed parts of the work of the British Standards Institution in the field of standardization of spectacles (Brit. J. Ophthal., 1956, 40, 611; 1959, 43, 509), but the publication of B.S. 3521, completing the series of Standards relating to spectacles, provides the opportunity for a general survey. The nine British Standards fall into two categories with some overlap. The...

Russell’s Logicism through Kantian Spectacles

Are their spectacles really necessary?

an experienced ophthalmic optician, I am also the Scottish representative of the British College of Ophthalmic Opticians and chairman of the National Optical Consultative Committee. The main defect in your editorial lies in the assumption that '80-90% of the prescriptions' for the 516 wearers of supposedly unnecessary spectacles out of 13 800 school children aged 10 years or less 'have been iss...

Presbyopic spectacles in elderly Tanzanians.

does exist. Wong et al. had considered variables that were closely related to one another (which was supposed to be evaluated by Pearson’s correlation coefficients or by clinical judgment) and chose only the most significant one. However, correlations among selected variables cannot be totally avoided. The variance inflation factor can be used to evaluate the extent of collinearity, but selecti...