At what intraocular pressure level should a patient be referred urgently in PACG cases?

In cases of Primary Angle Closure Glaucoma (PACG), intraocular pressure (IOP) is a critical factor that can lead to serious complications if not addressed urgently. An IOP of 40 mmHg is generally considered a threshold that necessitates immediate referral for several reasons.

Firstly, IOP levels exceeding 21 mmHg are typically regarded as abnormal and suggestive of a risk for glaucoma. When IOP reaches 40 mmHg, it indicates significant ocular hypertension and poses an immediate risk to the optic nerve. This is particularly pertinent in PACG, where the angle closure can lead to rapid increases in pressure, resulting in symptoms such as severe eye pain, blurred vision, and nausea.

Secondly, at this pressure level, there is a high likelihood of progressive optic nerve damage and potential visual field loss if not treated promptly. Medical interventions aimed at reducing IOP are essential during an acute attack to prevent irreversible damage.

While higher pressure levels, such as 50 mmHg or 60 mmHg, are severe and also warrant urgent care, the point at which intervention becomes critical for PACG is typically around the 40 mmHg mark. Thus, referring the patient urgently at this level allows for timely treatment to alleviate pressure and protect vision.