Retrospective analysis of risk factors for late presentation of chronic glaucoma

Background-Why some individuals present to the ophthalmologist in the early stages of chronic glaucoma but others present with very advanced visual fi eld loss is a question which has received little attention. This study is a n attempt to identify some basic characteristics of people who present with late glaucoma. Methods-A retrospective case-control study by medical record review was emp loyed. 100 cases and 100 controls were identified from the notes of patient s presenting to Moorfields Eye Hospital glaucoma service between July 1993 and July 1995. Cases were defined as new patients presenting with absolute field loss within five degrees of fixation and a cup to disc ratio of great er than 0.8 in one or both eyes. Controls were new patients with no absolut e field loss within 20 degrees in either eye, but otherwise typical glaucom atous field loss and a cup to disc ratio of greater than 0.5 or a differenc e of 0.2 or more between the discs. Results-The ethnic origin, sex, referral source, presenting IOP, and age of the subjects studied were independently associated with late presentation. An African Caribbean patient is estimated to be four and a half times more likely to attend with advanced field loss than a white patient of similar age, sex, IOP, and referral source (adj OR: 4.55, 95% CI [1.57, 13.18]). A female patient is estimated to be one third (0.34, [0.15, 0.74]) as likely to attend late than a male patient of the similar age, IOP, ethnic origin, and referral source. A patient referred via any source other than an optome trist with the correct diagnosis is estimated to be greater than four times (4.32 [1.89, 9.88]) more likely to be a late attender than a patient of th e same sex, ethnicity, and similar age but referred with a diagnosis of gla ucoma. There was a trend of increasing odds of late presentation with incre asing age (adj OR per 10 years, baseline 40-49 years 1.68 [1.22, 2.20]). A patient whose presenting IOP is 21-25 nun Hg is estimated to be a quarter ( 0.24, [0.09, 0.64]) as likely to attend with advanced field loss than a pat ient of the same ethnic origin, sex, age, referral source, but with present ing IOP of greater than 31 nun Hg. Conclusions-These data strongly suggest that certain subgroups of patients with glaucoma are likely to be at greater risk of presenting with advanced and irremediable field loss.