Interactive OCT helps suspect glaucoma patients

Anatomical structure of the eye conforms to expected average dimensions and this is likely to vary according to factors such as age, refractive status, and disease processes. For this reason, OCTs (and instruments such as visual fields analysers) incorporate normative values against which the data of any single patient may be compared and flagged up if falling outside this expected normalised value.

Each instrument manufacturer uses its own normative database and these are based on different numbers of previously assessed and published data sets. Typically, results falling outside the expected normalised values are flagged up in traffic light colour coding, with green representing normal limits, orange as suspect and red as outside expected limits. Useful as these are as a guide, problems may occur if they are the sole basis for a referral without other factors (such as risk factors for a particular disease, or congenital and aberrant anatomical differences).