Glaucoma Screening

All content on Eyewiki is protected by copyright law and the Terms of Service. This content may not be reproduced, copied, or put into any artificial intelligence program, including large language and generative AI models, without permission from the Academy.

Article initiated by:

Emily Lawrence

All contributors:

Alejandro Fernando Ibarra Lozano, MD, Ahmad A. Aref, MD, MBA, Alejandro Fernando Ibarra Lozano, MD, Dr John Davis Akkara (MBBS, MS, FAEH, FMRF), Qi N. Cui, MD PhD

Assigned editor:

Qi N. Cui, MD PhD

Review:

Assigned status Update Pending

 by Qi N. Cui, MD PhD on February 4, 2022.

add
Contributing Editors:	add

Introduction

Glaucoma is the most common cause of irreversible blindness worldwide. Many patients with glaucoma are asymptomatic early in the course of disease, given the often slowly progressive nature of the condition.  Therefore, screening of higher-risk patients is essential to minimize vision loss and prevent blindness.

Disease

Glaucoma is a chronic progressive optic neuropathy, characterized by damage to the optic nerve and retinal nerve fiber layer. Glaucoma is often, but not always, associated with elevated intraocular pressure (IOP). If untreated, the disease can lead to irreversible blindness. Glaucoma is a heterogeneous group of conditions which may be classified into two broad categories: open-angle glaucoma (OAG) and angle-closure glaucoma (ACG). In OAG, the most common type of glaucoma, the onset of disease is usually insidious with patients experiencing slowly progressive difficulty with peripheral vision with associated functional limitations. Acute ACG, in contrast, involves an abrupt elevation in IOP, leading to blurry vision, eye pain, nausea and vomiting, and which can rapidly lead to loss of sight.

Risk Factors

Important risk factors for primary open-angle glaucoma (POAG) include: elevated intraocular pressure, advanced age, positive family history, Black or Latinx race/ethnicity, and myopia.

Several medical conditions are associated with glaucoma, including: diabetes, Cushing disease, OSA, migraine, and causes of anterior chamber inflammation such as sarcoidosis, HLA B27-associated diseases, rheumatoid arthritis, SLE, as well as several infectious diseases (e.g., HSV, VZV, syphilis, toxoplasmosis). Additionally, the use of corticosteroids in any formulation or route of administration elevates IOP and is associated with an increased risk of glaucoma.

While angle-closure glaucoma is primarily due to anatomically susceptible patients with narrow drainage angles, anterior chamber inflammation can precipitate synechial angle closure, while certain medications are known to precipitate acute angle closure, including anticholinergics and sulfonamides.

Epidemiology

Glaucoma affects approximately 2.5 million Americans. It is the second leading cause of irreversible blindness in the United States and the leading cause of blindness in Black and Latinx persons. Worldwide, glaucoma is the leading cause of irreversible blindness, and there are estimated to be 76.0 million affected individuals.

Screening

In 2013, the US Preventive Services Task Force did not recommend population-based glaucoma screening in asymptomatic adults, and a draft recommendation issued in 2021 concurred, citing insufficient evidence of net benefit of preventing potential vision loss vs. harm due to over-diagnosis or unnecessary treatment.  However, glaucoma screening can be useful and cost-effective in higher-risk populations, such as those with a strong family history of the disease or persons of nonwhite race. The American Academy of Ophthalmology recommends a baseline comprehensive eye exam at age 40 with follow up based on risk factors. Medicare and Medicaid currently covers glaucoma examinations by eye care professionals for patients with diabetes, a family history of glaucoma, Black patients 50 and older, and Latinx patients 65 and older.

Community-based screening programs have shown to be effective and affordable for identifying patients with glaucoma and other treatable ophthalmic conditions, and such programs increase access to care for historically underserved populations. Based on 2 large prospective trials, an editorial by Kolomeyer et al. 2021 [CQ1] identified several important considerations when designing such a program, including: collaborating with primary care offices and Federally Qualified Health Centers, engaging language- and race-concordant staff according to the population served, allowing same-day and walk-in appointments for ease of participation, and using multiple strategies to improve follow-up adherence.

Examination

A comprehensive eye exam that includes screening for glaucoma should involve: visual acuity assessment, pupil examination, anterior segment examination including assessment of the drainage angle width, IOP measurement (applanation tonometry is the gold standard), optic nerve examination, and fundus examination.

If a patient is considered a glaucoma suspect, further testing includes gonioscopy, pachymetry, tonometry, perimetry, careful examination of the optic nerve, and ocular imaging using OCT. Computer-based imaging and stereoscopic photography may provide different and complementary information about optic nerve status. Functioning in concert, non-physician volunteers may be trained to first assess visual acuity, visual fields, central corneal thickness, and IOP, followed by an ophthalmologist to examine the retina and optic disc. Portable technologies can assist in these endeavors, such as portable frequency doubling technology (FDT) to assess visual field, rebound tonometry to assess IOP, and the PanOptic ophthalmoscope to view the optic disc. Smartphone- and tablet-adapted fundus cameras are also available, and are becoming increasingly affordable for widespread use.

A much more in-depth look at glaucoma care is covered in the EyeWiki entry, Primary Open-Angle Glaucoma