Gonioscopy remains an important diagnostic procedure in classifying patients on the angle closure spectrum. Patients who develop acute angle closure crisis should be treated immediately to lower IOP, followed by a prompt LPI. Study results have shed light on how to manage angle closures.
Glaucoma is a neurodegenerative disease characterized by optic nerve damage causing progressive and permanent vision loss.1 It is estimated to affect 76 million people worldwide, increasing to 112 million by the year 2040.2 Primary-angle closure glaucoma (PACG) accounts for 25 percent of all glaucoma globally, but is responsible for nearly half of all glaucoma-related blindness.3
The angle closure spectrum includes three stages (Table 1). Primary-angle closure suspect (PACS) is defined as having at least 180° of iridotrabecular contact (ITC) with an intraocular pressure (IOP) below 21 mm Hg and no peripheral anterior synechiae (PAS). Primary angle closure (PAC) has the same amount of iridotrabecular contact with an IOP above 21 mm Hg or the presence of PAS. PACG exists when the criteria for PAC is met and there is evidence of glaucomatous optic neuropathy.4
Risk factors include age, Inuit and Asian race, family history, female sex, shorter axial length, smaller anterior chamber depth, and lens parameters.5-8 Increased prevalence of relative pupillary block and thus greater risk of PAC is seen as lens thickness increases throughout life.9
Women carry three times the risk of men in developing PACG due to anatomical differences such as smaller anterior chamber depth and axial length in women.10 A longer life span in women also contributes to the risk.3
Over three-quarters of those affected with PACG worldwide live in Asia, including 3.1 million people blind in at least one eye due to PACG living in China.11 Prevalence studies conducted on different Asian-American populations show higher rates of the angle closure spectrum compared to non-Hispanic whites.12-14
Despite the disproportionate number of Asians diagnosed as being on the angle closure spectrum, a study of over 2 million managed-care patients in the United States found a 1.35 percent prevalence of PACG in Caucasians over the age of 40.14
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