**6. How to define controlled glaucoma?**

The aim of treatment at present is controlling the IOP to prevent further deterioration in visual fields. The loss of visual field is irreversible. The ideal IOP should be low enough to prevent visual field loss without compromising the functions of the eye. Each patient has a desirable range of IOP—target IOP, which varies between individuals and depends on the aggressiveness of the disease. The aggressiveness of the disease is determined by the IOP, its fluctuations, the type of glaucoma, and the damage to the optic disc and visual field. In normal tension glaucoma, the target IOP is usually less than in other types of glaucoma, because even with normal pressures, the damage continues to progress. The IOP is constantly changing. It depends on the hour (diurnal variations) and seasons. Most but not all subjects have the highest peak in IOP during the early morning.

To be considered as "controlled glaucoma," the IOP should be within its target during the entire day in a long follow-up with constant use of anti-glaucoma medications or postoperatively. The patients should take their medications properly at a preset times and continuously. Thus, patients intolerant to anti-glaucoma medications or uncompliant are not considered controlled. The IOP may be assessed by diurnal curve every 4 hours, usually between 8 AM and 8 PM, because it changes constantly or even every 2 hours.
