Medical Management of Glaucoma in the 21st Century from a Canadian Perspective

Table 1

Glaucoma classification according to severity of the disease.

(a) Open-angle glaucoma reproduced from [1], with permission from Elsevier

Suspect	One or two of the following: () IOP > 21 mm Hg; () Suspicious disc or C/D asymmetry of >0.2; () Suspicious 24-2 (or similar) VF defect
Early	() Early glaucomatous disc features (e.g., C/D < 0.65); () Mild VF defect not within 10° of fixation (e.g., MD better than −6 dB on HVF 24-2)
Moderate	() Moderate glaucomatous disc features (e.g., vertical C/D 0.7–0.85); () Moderate VF defect not within 10° of fixation (e.g., MD from −6 to −12 dB on HVF 24-2)
Severe	() Advanced glaucomatous disc features (e.g., C/D > 0.9); () VF defect within 10° of fixation^† (e.g., MD worse than −12 dB on HVF 24-2)

C/D, cup-to-disc; HVF, Humphrey visual field; IOP, intraocular pressure; MD, mean deviation; VF, visual field.
refers to vertical C/D ratio in an average size nerve. If the nerve is small, then a smaller C/D ratio may still be significant; conversely, a large nerve may have a large vertical C/D ratio and still be within normal limits. † also considers baseline 10-2 VF (or similar).
Recent evidence indicates that ganglion cell loss should also be taken into consideration when staging/classifying glaucoma [2].

(b) Angle closure

Disease staging	≥180° appositionally closed (where posterior TM not visible [grade 1])	Ocular hypertension and/or peripheral anterior synechiae	Ganglion cell, optic nerve, and visual field damage
PACS	+	−	−
PAC	+	+	−
PACG	+	+	+

PAC, primary angle closure; PACS, primary angle closure suspect; PACG, primary angle closure glaucoma.
The above definitions could be used to guide decisions regarding the target IOP range (i.e., for patients with more advanced disease and/or evidence of rapidly progressing disease, targeted IOP should be in the lower targeted range). To achieve this, patients may require a more aggressive therapy from initiation of therapy; see Figure 3, suggested range for initial target IOP, and Figure 5, proposed treatment algorithm.