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Biomedical subjects

A Sorsby

Publications and source records attributed to A Sorsby.

17 recordsLinked to original sources

Steiger on refraction: a reappraisal.

Seventy years ago Steiger, a Swiss ophthalmologist, found the distribution of corneal powers to follow a normal (binomial) curve. He noted a wide range of values among emmetropes, and he also knew that their axial lengths varied significantly. He expected that normal distributions would be found for other components of refraction and also for refraction as a whole, and in seeking a controlling mechanism he recalled the multifactorial pattern of inheritance of such characteristics as stature. The present study employs modern mathematical techniques to test the validity of 2 related hypotheses: that the components of refraction are correlated and that a polygenic mode of inheritance is responsible for determining the refractive power of the eye. In the light of this study and of other modern knowledge about refraction Steiger's work is reassessed. Most of his views are vindicated, although his assumption of a normal distribution for refraction as a whole could not be justified. His contribution to the understanding of refraction establishes him among the great names in ophthalmology.

Adult↗

Bilateral retinoblastoma: a dominantly inherited affection.

Ten survivors of sporadic bilateral retinoblastoma had 14 offspring, of whom eight were affected, seven of them in both eyes. Other reports from the literature raise the total of similar unselected cases to 19 survivors with a total of 39 offspring, of whom 17 were affected in both eyes and three in one eye.The high incidence of the bilateral affection in dominantly inherited retinoblastoma-as recorded in the literature-and in the offspring of survivors from sporadic bilateral retinoblastoma, as reported in the present study, establish all cases of bilateral retinoblastoma as a dominant disorder either in transmission or as a new mutation. This disorder, though fully or almost fully penetrant, is not always fully expressed. A small proportion, probably about 5 to 10% of all cases of the much more common sporadic unilateral affection, are in fact incompletely expressed germinal mutations for bilateral retinoblastoma. There is some evidence that histological appearances may distinguish these potentially transmissible unilateral tumours from the mass of unilateral retinoblastoma which have no genetic significance.

Adult↗