Classification of primary angle closure disease

Primary angle closure disease, PACD, has had a plethora of classifications and terminologies. The International Society of Geographical and Epidemiological Ophthalmology (ISGEO) classification was a simple classification, extremely useful in surveys, but could not be clinically applied because of the varied presentation of PACD.

Reviewing the literature, it was seen that the landmarks in progression of PACD were an anatomical predisposition; iridocorneal apposition/adhesions; chronic rise in intraocular pressure (IOP), despite an iridotomy; and glaucomatous optic neuropathy. Therefore, a staging system for PACD is proposed. PACD suspect--occludable angle; PACD I--occludable angle with evidence of closure, but a normal IOP after iridotomy; PACD II--peripheral anterior synechiae in an occludable angle with a chronically raised IOP after iridotomy, with or without a suspicious optic nerve head; and PACD III--peripheral anterior synechiae in an occludable angle, with a raised IOP after iridotomy, and glaucomatous optic neuropathy.

This proposed classification has amalgamated all the clinically described subtypes of PACD--subacute, acute, chronic, symptomatic, and asymptomatic--into a staging, based on extent of damage to the outflow channels and optic nerve head, providing a basis for standardized therapy and possibly a quantifiable long-term prognosis.