Figure 1.

Glaucoma Color Graph. The stage of disease is graded considering the amount of disc damage estimated by DDLS. The optic discs may be graded in three zones: green, yellow or red. In the green zone, which comprises DDLS of 1–4, the patients do not have definite damage. When a patient is in the yellow zone (with a DDLS of 5–7), the optic nerve is definitely damaged, but the person may still be asymptomatic. It is certain that the optic disc is not normal. Finally, when a person is already in the red zone (with a DDLS of 8, 9 or 10), that is, the person already has a disability. The patient may have decreased quality of life or impaired ability to perform the daily activities.