is a the condition of the eye where the intraocular pressures are too high to maintain the normal health of the optic nerve
. Damage to the fibres of the nerve proceeds very slowly when the pressures are not that high. In your case, you are on one of the better known medications for IOP control, however, the eye may get 'immune' to the medication and there can be a slow rise in the IOP even after many years of control with the same medication. Other drugs are then added or sustituted. If there is damage that starts,, only a visual field
or an OCT( optical coherence tomography
) can detect it in early stages. The patients vision or the funduscopy cannot detect early changes. Since any change secondary to glaucoma can only be halted, never reversed, the extra precaution is worth it.