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.
1. World Health Organization. Global Data on Visual Impairments 2010. Geneva: World Health Organization, 2012. Available at: http://www.who.int/blindness/GLOBALDATAFINALforweb.pdf?ua=1. Accessed 8/25/17.
2. Foster PJ, Johnson GJ. Glaucoma in China: how big is the problem? Br J Ophthalmol. 2001 Nov;85(11):1277-82. â€¨
3. Quigley HA, Broman AT. The number of people with glaucoma worldwide in 2010 and 2020. Br J Ophthalmol. 2006 Mar;90(3):262-7.â€¨
4. Varma DK, Kletke S, Rai AS, Ahmed IIK. Proportion of undetected narrow angles or angle closure in cataract surgery referrals. Can J Ophthalmol. 2017 Aug;52(4):366-372.
5. Cumba RJ, Nagi KS, Bell NP, Blieden LS Chuang AZ, Mankiewicz KA, Feldman RM. Clinical outcomes of peripheral iridotomy in patients with the spectrum of chronic primary angle closure. ISRN Ophthalmol. 2013 Jun 26;2013:828972.
6. Friedman DS. Epidemiology of angle-closure glaucoma. J Curr Glaucoma Pract. 2007 May-Aug;1(1):1-3.
7. Varma DK, Simpson SM, Rai AS, Ahmed IIK. Undetected angle closure in patients with a diagnosis of open-angle glaucoma. Can J Ophthalmol. 2017 Aug;52(4):373-378.
8. Quigley HA. Angle-Closure glaucoma: concepts and epidemiology. Glaucoma Today. Available at: http://glaucomatoday.com/2009/08/GT0709_08.php/. Accessed 12/15/17.
9. Foster PJ, Buhrmann R, Quigley HA, Johnson GJ. The definition and classification of glaucoma in prevalence surveys. Br J Ophthalmol. 2002 Feb;86(2):238-42.
10. Azuara-Blanco A, Burr J, Ramsay C, Cooper D, Foster PJ, Friedman DS, Scotland G, Javanbakht M, Cochrane C, Norrie J; EAGLE study group. Effectiveness of early lens extraction for the treatment of primary angle-closure glaucoma (EAGLE): a randomised controlled trial. Lancet. 2016 Oct 1;388(10052):1389-1397.
11. Fricke TR, Mantzioros N, Vingrys AJ. Management of patients with narrow angles and acute angle-closure glaucoma. Clin Exp Optom. 1998 Nov-Dec;81(6):255-266.
12. Varma D, Adams WE, Phelan PS, Fraser SG. Viscogoniolasty in patients with chronic narrow angle glaucoma. Br J Ophthalmol. 2006 May;90(5):648-9.
13. Coleman AL, Yu F, Evans SJ. Use of gonioscopy in Medicare beneficiaries before glaucoma surgery. J Glaucoma. 2006 Dec;15(6):486-93.
14. Vagheri N, Wajda BN, Calvo CM et al. The Wills Eye Manual: Office and Emergency Room Diagnosis and Treatment of Eye Disease (7th ed.). 2017. Philadelphia: Wolters Kluwer Health/Lippincott Williams & Wilkins.
15. Foster PJ, Aung T, Nolan WP, Machin D, Baasanhu J, Khaw PT, Alsbirk PH, Lee PS, Seah SK, Johnson GJ. Defining ‘‘occludable’’ angles in population surveys: drainage angle width, peripheral anterior synechiae, and glaucomatous optic neuropathy in east Asian people. Br J Ophthalmol. 2004 Apr;88(4):486-90.
16. Lachkar Y, Bouassida W. Drug-induced acute angle closure glaucoma. Curr Opin Ophthalmol. 2007 Mar;18(2):129-33.
17. Acharya N, Nithyanandam S, Kamat S. Topiramate-associated bilateral anterior uveitis and angle closure glaucoma. Indian J Ophthalmol. 2010 Nov-Dec;58(6):557-9.
18. Asrani SG, Foster PJ, Palmberg PF, Ritch R. MD Roundtable: Expert Tips for Assessing the Narrow Angle. Available at: https://www.aao.org/eyenet/article/md-roundtable-expert-tips-assessing-n.... Accessed 8/25/17.
19. Chan P, Tham C. Commentary on effectiveness of early lens extraction for the treatment of primary angle-closure glaucoma (EAGLE). Annals Eye Science. Available at: http://aes.amegroups.com/article/view/3677. Accessed 12/15/17.