Editor,—The letter by Dayanet al 1 raises some interesting questions regarding the examination and referral of patients by optometrists for further investigation in relation to open angle glaucoma.

While the authors base their comments upon largely anecdotal evidence from a series of only 11 subjects from one referral source, there are nevertheless some important points to be answered from these comments.

Firstly, the College of Optometrists guidelines offer guidance based on clinical evidence to optometrists conducting eye examinations. They specifically encourage optometrists to conduct the appropriate tests on any individual patient as a matter of best practice. In the case of glaucoma, recommendations are made that visual field tests should be conducted on subjects over the age of 40, those with a family history of glaucoma, and those with suspicious optic discs or other risk factors.2

The majority of visual field tests used in optometric practice are based upon static perimetry (College of Optometrists annual clinical survey, 1998) and decisions then need to be made on the results obtained. Therefore, if one or two points are missed on a central field test does that mean an abnormality is present? The optometrist needs to make a judgment on this issue in the light of the complete clinical findings rather than simply exert a pass/fail criterion from a screening test.

Not surprisingly most glaucoma patients in hospital clinics are referrals from optometrists but evidently …