In a survey covering 275,600 eye examinations by optometrists, 0.55% resulted in a referral to a medical practitioner for suspected glaucoma. Some 85-90% of the referred patients subsequently attended for examination by a consultant ophthalmologist. Of these, rather more than a third were confirmed as having glaucoma, almost a third were discharged as not having the disease, and the diagnosis was borderline for the remainder. The survey's results imply that optometrists detect about 20,000 cases of glaucoma in England and Wales each year.