Table 4

Classification of primary angle closure (PAC)

In epidemiological research this has most often been defined as an angle in which ≥270° of the posterior trabecular meshwork (the part which is often pigmented) cannot be seen. This definition is arbitrary and its evaluation in longitudinal study is an important priority.
Producing a more evidence based definition of this parameter is a major research priority.
(1) Primary angle closure suspect
An eye in which appositional contact between the peripheral iris and posterior trabecular meshwork is considered possible (see footnote).
(2) Primary angle closure (PAC)
An eye with an occludable drainage angle and features indicating that trabecular obstruction by the peripheral iris has occurred, such as peripheral anterior synechiae, elevated intraocular pressure, iris whorling (distortion of the radially orientated iris fibres), “glaucomfleken” lens opacities, or excessive pigment deposition on the trabecular surface. The optic disc does not have glaucomatous damage.
(3) Primary angle closure glaucoma (PACG)
PAC together with evidence of glaucoma, as defined above.