Final Research Plan

Primary Open-Angle Glaucoma: Screening

June 04, 2020

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The analytic framework depicts the relationship between the Key Questions for the systematic review within the context of the populations, interventions, outcomes, and harms of screening and treatment for glaucoma. The far left of the framework describes the target population as asymptomatic adults without known open-angle glaucoma. To the right of the population is a line representing the diagnostic accuracy of screening leading to the diagnosis of open-angle glaucoma (Key Question 4) and instruments for identify patients at higher risk of open-angle glaucoma (Key Question 5), and an additional arrow indicates potential harms of screening (Key Question 2). A subsequent line and area of the framework leads from the open-angle glaucoma diagnosis to outcomes from treatment (Key Questions 6, 8, and 10), including the intermediate outcomes of intraocular pressure, optic nerve assessment, and visual field assessment, and the health outcomes in a separate box connected by a dotted line of reduced visual impairment and improved patient-reported outcomes. An additional arrow indicates potential harms of treatment (Key Questions 7, 9, and 11). An overarching arrow leading from the initial screening population to both intermediate and health outcomes represents the direct effects of screening (Key Question 1) and referral to an eye health provider (Key Question 3) on those outcomes.

*Includes open-angle glaucoma suspects.
Note: Subpopulations of interest include those defined by age, sex, race/ethnicity, and setting (e.g., rural or urban).

Abbreviation: KQ = Key Question.

  1. What are the effects of screening for open-angle glaucoma versus no screening on a) intraocular pressure, visual field loss, visual acuity, or optic nerve damage or b) visual impairment, quality of life, or function?
  2. What are the harms of screening for open-angle glaucoma versus no screening?
  3. What are the effects of referral to an eye health provider versus no referral on a) intraocular pressure, visual field loss, visual acuity, or optic nerve damage or b) visual impairment, quality of life, or function?
  4. What is the accuracy of screening for diagnosis of open-angle glaucoma?
  5. What is the accuracy of instruments for identifying patients at higher risk of open-angle glaucoma?
  6. What are the effects of medical treatments for open-angle glaucoma versus placebo or no treatments on a) intraocular pressure, visual field loss, visual acuity, or optic nerve damage or b) visual impairment, quality of life, or function?
  7. What are the harms of medical treatments for open-angle glaucoma versus placebo or no therapy?
  8. What are the effects of newly U.S. Food and Drug Administration (FDA)–approved medical treatments (latanoprostene bunod and netarsudil) versus older medical treatments on a) intraocular pressure, visual field loss, visual acuity, or optic nerve damage or b) visual impairment, quality of life, or function?
  9. What are the harms of newly FDA-approved medical treatments versus older medical treatments?
  10. What are the effects of laser trabeculoplasty for the treatment of open-angle glaucoma versus no trabeculoplasty or medical treatment on a) intraocular pressure, visual field loss, visual acuity, or optic nerve damage or b) visual impairment, quality of life, or function?
  11. What are the harms of laser trabeculoplasty for the treatment of open-angle glaucoma versus no trabeculoplasty or medical treatment?

Contextual questions will not be systematically reviewed and are not shown in the Analytic Framework.

  1. What is the association between changes in intraocular pressure, visual field loss, visual acuity, or optic nerve damage following treatment for open-angle glaucoma and improvement in visual impairment, quality of life, or function, and what is the association between changes in intraocular pressure and visual field loss?

The Research Approach identifies the study characteristics and criteria that the Evidence-based Practice Center will use to search for publications and to determine whether identified studies should be included or excluded from the Evidence Review. Criteria are overarching as well as specific to each of the key questions.

Category Include Exclude
Definition of disease Primary open-angle glaucoma: Glaucoma defined by presence of glaucomatous optic disc changes and retinal nerve fiber layer changes, with or without associated visual field changes or elevated intraocular pressure

Glaucoma suspect: Patients do not meet criteria for glaucoma but have a consistently elevated intraocular pressure, a suspicious appearance of the optic nerve, or visual field abnormalities consistent with glaucoma

  
Populations KQs 1–5: Asymptomatic adults age 40 years and older without visual symptoms

KQs 6–11: Adults with screen-detected, asymptomatic, or early primary open-angle glaucoma

 KQs 1–5: Patients with visual symptoms, case-control studies of patients known to have open-angle glaucoma and normal controls

KQs 6–11: Patients with open-angle glaucoma and severe visual field or visual deficits; patients with narrow-angle glaucoma, secondary glaucoma, juvenile glaucoma, or other glaucoma
Interventions KQs 1, 2, 4, 5: Screening with a comprehensive eye examination (as defined in the studies) by an eye health provider; screening tests performed in primary care or applicable to primary care; and instruments for identifying persons at increased risk of open-angle glaucoma

KQ 3: Referral to an eye specialist

KQ 4: Diagnostic tests that are currently used:

  1. Comprehensive eye examination
  2. Ophthalmoscopy, direct and indirect
  3. Optic disc photography, including nondigital and digital monoscopic and stereoscopic photography, and planimetry
  4. Perimetry, including high-pass, motion, flicker perimetry, and yellow and blue perimetry
    1. White-on-white standard automated perimetry, including suprathreshold and threshold (classic Humphrey visual field)
  5. Tonometry, contact and noncontact tonometry
    1. Goldmann applanation tonometer
    2. Noncontact tonometer (air puff)
    3. Tono-Pen
  6. Optical coherence tomography and optical coherence tomography angiography
  7. Fundus photography or computerized imaging of the posterior pole, optic disc, or retinal nerve fiber
  8. Pachymetry, when used in conjunction with another test to diagnose glaucoma
  9. Scanning laser polarimetry
  10. Afferent pupillary defect
  11. Ganglion cell complex measurement  

KQs 6–11:

  • First-line medical treatments (prostaglandin analogues, beta blockers, alpha2 agonists, and carbonic anhydrase inhibitors)
  • Selective laser trabeculoplasty
  • Latanoprostene bunod
  • Netarsudil
 KQ 4: Screening tests that are no longer used

KQs 6–11: Second-line medical therapies, surgery, non-FDA–approved therapies, therapies not commonly used as first-line therapy in U.S. practice
Comparisons KQs 1, 2: No screening

KQ 3: No referral

KQs 4, 5: Reference standard for open-angle glaucoma (as defined in the studies)

KQs 6–11: Placebo, no treatment, or first-line medical therapies (for selective laser trabeculoplasty, latanoprostene bunod, and netarsudil)

 Comparisons involving second-line medical therapies or surgery
Outcomes KQs 1–3, 6–11: Intraocular pressure, visual field loss, visual acuity, optic nerve damage, visual impairment (defined as visual acuity <20/70 or <20/100), quality of life, function, harms (e.g., eye irritation, corneal abrasion, infection, anterior synechiae, or cataracts)

KQs 4, 5: Measures of diagnostic accuracy

 Other (not listed) outcomes
Setting Studies conducted in high-income settings applicable to U.S. practice; includes studies performed in primary care (including use of telemedicine) and specialty settings  
Study Design RCTs of screening and treatment; cohort studies for harms of treatment if RCTs not available; population-based cohort or cross-sectional studies of diagnostic accuracy; high-quality systematic reviews Case series, case reports, case-control studies, and diagnostic accuracy studies using the healthy eye of a person with glaucoma as the control
Study Quality Fair- or good-quality studies Poor-quality studies

Abbreviations: FDA=U.S. Food and Drug Administration; RCT=randomized, controlled trials.

The draft Research Plan was posted on the USPSTF website for public comment from February 13 to March 11, 2020. The USPSTF reviewed the comments and made no changes to the scope or Key Questions, although some edits were made for clarity. The USPSTF revised the inclusion/exclusion criteria to clarify the included and excluded diagnostic tests for glaucoma; tests that are no longer used were excluded.