The next patient sitting in your chair may have narrow angles.
Patients with narrow angles can present along a wide spectrum of angle closure, from anatomically narrow angles with no glaucomatous damage to an acute angle closure attack.
Proper gonioscopy can guide management direction and have a significant long-term impact on visual outcome in these patients.
Looking at narrow angles
Glaucoma is the leading cause of irreversible blindness worldwide.1 Angle closure is the underlying mechanism in one-third of primary glaucomas, and it is responsible for half of all glaucoma blindness worldwide.2-4
Primary-angle closure glaucoma (PACG) is a leading cause of bilateral blindness worldwide, estimated to affect between 16 and 20 million people.4,5 Although angle-closure glaucoma (ACG) is less prevalent than open-angle glaucoma, it may blind a higher proportion of individuals due to the underlying nature of the disease.6
Angle closure results from appositional closure of the anterior chamber angle and can be divided into primary and secondary classifications, with the former indicating no detectable cause besides anatomical predisposition and the latter arising from a known pathology.
Angle closure disease can be categorized as primary angle-closure suspect, primary angle closure, and angle-closure glaucoma.7-9
A narrow-angle diagnosis is typically defined an anatomical disposition in which the trabecular meshwork cannot be seen in more than 180 degrees.10 An angle-closure suspect has narrow angles or approximately 180 degrees of iridotrabecular apposition without other glaucomatous associations.
Related: Managing glaucoma in women
Primary angle-closure patients will have a narrow or closed angle with an elevated intraocular pressure (IOP). In some cases, there may also be peripheral anterior synechiae present, resulting from long-term iridotrabecular contact.7,11,12 Patients with ACG will have a closed angle and glaucomatous damage evidenced by visual field, nerve fiber layer, or optic nerve damage with or without peripheral anterior synechiae.5
Angle closure risk factors
Demographics at risk for angle closure include female gender; advanced age; and Asian, Indian, or Inuit descent.4,10,11 Ocular risk factors include smaller eyes (shorter axial length, smaller corneal diameter), narrow angles, shallower anterior chamber depth, thicker and/or anteriorly displaced lens, and hyperopic refractive error.10
Patients are typically asymptomatic due to the slow nature of closure unless undergoing an acute angle closure attack, in which the symptoms may range from pain, nausea, and vision loss to redness and halos around lights.