Primary care: choice and opportunity

Cruysberg et al is that delay in diagnosis should be prevented as far as possible.Cruysberg and colleagues offer a helpful definition of "myopia plus" (as myopia associated with skeletal, central nervous, or vascular disease) to alert doctors to request appropriate diagnostic investigations.What are the implications of Cruysberg et al's observations for clinical practice and research?Firstly, their work emphasises the importance of undertaking appropriate tests in any patients with onset of severe myopia in childhood.This view is supported by a study of tests on 7500 urine and 4500 blood samples from 9000 selected patients, which resulted in the detection of four patients with homocystinuria.'8The natural course of homocystinuria is that lens dislocation will have occurred in half ofpatients by about 8 years of age whereas half of patients will have reached 29 years before a thromboembolic event occurs.6There is therefore a window of opportunity of about 21 years to intervene to prevent thrombosis if a diagnosis is made at the time of lens dislocation.Secondly, Cruysberg et al's findings suggest the need for research into identifying suitable tests to undertake mass neo- natal screening.Unfortunately, the use of hyper- methioninaemia for this purpose is unreliable,6 19 and perhaps research would be better directed towards tests based on molecular genetic techniques.