Who Should Get Visual Field Testing? A Population-Based Framework

This audio article is from VisualFieldTest.com.Read the full article here: https://visualfieldtest.com/en/who-should-get-visual-field-testing-a-population-based-frameworkTest your visual field online: https://visualfieldtest.comSupport the show so new episodes keep coming: https://www.buzzsprout.com/2563091/supportExcerpt:Who Should Get Visual Field Testing? A Population-Based Framework Visual field testing measures how well a person sees across the central and peripheral parts of the visual field. It is especially important because many eye and brain disorders damage peripheral vision gradually, without causing obvious symptoms at first. However, routine visual field testing is not necessary for every healthy, asymptomatic adult. The highest value comes from testing people whose examination, medical history, medication use, or disease pattern creates a meaningful risk of developing or worsening field loss. This targeted approach helps detect silent damage while limiting false-positive results, unnecessary anxiety, and avoidable testing. What Visual Field Testing Detects Most clinical visual field tests use automated static threshold perimetry. One eye is tested at a time while the patient looks at a central target and presses a button whenever a spot of light is seen. The test can identify: Peripheral blind spots caused by glaucoma Central or paracentral defects affecting reading or fixation Bitemporal defects associated with pituitary or other chiasmal disease Altitudinal defects associated with ischemic optic neuropathy Enlargement of the blind spot associated with papilledema Concentric peripheral loss caused by some toxic retinal disorders Hemifield loss after stroke or damage to the visual pathways Visual field testing is different from a visual acuity test. A person may still read the eye chart well while having important peripheral field loss. The two eyes also overlap, allowing one eye to compensate for defects in the other. Because visual field testing depends on attention, learning, fatigue, and response consistency, one abnormal result should usually be confirmed unless the pattern is clearly urgent. National Institute for Health and Care Excellence glaucoma guideline () The Population-Based Principle: Targeted Testing Rather Than Universal Screening The United States Preventive Services Task Force has found insufficient evidence to recommend routine population-wide screening for primary open-angle glaucoma in asymptomatic adults. This does not mean that visual field testing is unhelpful. Rather, it means that testing is more useful when directed toward people with identifiable risk factors or suspicious findings. United States Preventive Services Task Force recommendation () A comprehensive eye examination is still important, particularly as people get older or develop medical risk factors. The American Academy of Ophthalmology recommends a baseline comprehensive eye examination around age 40, with follow-up based on individual risk. Visual field testing should then be added when there is a suspicious optic nerve, elevated intraocular pressure, a relevant medication exposure, visual symptoms, or a disorder affecting the optic nerve or brain. American Academy of Ophthalmology glaucoma screening information () The groups most likely to benefit from routine or repeated testing are: Glaucoma suspects People with ocular hypertension People with established glaucoma Patients with neuro-ophthalmic disease Patients taking medications that can injure the retina or optic nerve Evidence on Asymptomatic Visual Field Loss Glaucoma may be advanced before a patient notices it Glaucoma usually develops slowly. Early defects often occur outside the central line of sight, and the brain can partially compensate for missing information. As a result, patients may not notice a problem until the disease is advanced. Population-based research has found that approximately half of people with manifest glaucoma in developed countries may be unaware that they have the disease. In a screening cohort from the Early Manifest Glaucoma Trial, one-third of people with previously undetected glaucoma had advanced visual field loss in at least one eye. Early Manifest Glaucoma Trial population screening study () The risk is not limited to people with poor visual acuity. A patient can have good central vision and still have loss in the upper, lower, nasal, or temporal field. Visual field loss has also been associated with reduced mobility, falls, and lower quality of life in population studies. Rotterdam Study of visual field loss and daily functioning () Why asymptomatic loss matters clinically Detecting field loss before a patient notices it can: Confirm that structural changes are functionally important Establish the stage of glaucoma Identify patients who need pressure-lowering treatment Reveal progression before a major daily-life problem develops Prompt neurological imaging when the pattern is not typical for glaucoma Trigger medication review when toxicity is suspected The goal is not simply to find an abnormal test. The goal is to find a repeatable, clinically meaningful change that alters care. Glaucoma Suspects A glaucoma suspect may have one or more of the following: Elevated intraocular pressure A large or asymmetric optic nerve cup Suspicious thinning of the retinal nerve fiber layer A disc hemorrhage A suspicious or borderline visual field A strong family history of glaucoma Thin central corneas Myopia, pseudoexfoliation, pigment dispersion, or other risk factors A person can be a glaucoma suspect even when the visual field is normal. In this situation, the field provides an important functional baseline against which later tests can be compared. Who among glaucoma suspects benefits most? Visual field testing is particularly valuable when a patient has: A suspicious optic nerve appearance Asymmetry between the two optic nerves Retinal nerve fiber layer or ganglion cell thinning on imaging Repeatedly elevated intraocular pressure A first-degree relative with glaucoma A disc hemorrhage A thin central cornea High myopia A previous borderline or abnormal field A visual complaint that is not explained by glasses, cataract, or retinal disease The American Academy of Ophthalmology recommends that observed primary open-angle glaucoma suspects generally be reassessed at least every 12 to 24 months, with more frequent assessment when several risk factors are present. American Academy of Ophthalmology Primary Open-Angle Glaucoma Suspect Preferred Practice Pattern () How visual field results change care in a glaucoma suspect Normal and stable field: continued observation may be appropriate. One questionable abnormal field: repeat the test, check reliability, and compare it with the optic nerve and imaging. Repeatable glaucomatous pattern: the diagnosis may change from “suspect” to glaucoma. Field loss that does not match the optic nerve: consider a neurological or retinal cause. Paracentral loss: closer monitoring is often needed because central function may be threatened even when the overall field appears mild. A visual field should therefore be interpreted together with intraocular pressure, optic nerve examination, retinal imaging, corneal thickness, and the patient’s history. People With Ocular Hypertension Ocular hypertension means that the pressure inside the eye is consistently elevated, but there is not yet definite optic nerve damage or visual field loss. Many people with ocular hypertension never develop glaucoma. The Ocular Hypertension Treatment Study found that about 9.5% of untreated participants developed glaucoma over five years, compared with about 4.4% of participants who received pressure-lowering treatment. Risk was not equal among all participants. Higher pressure, older age, larger cup-to-disc ratio, and thinner central corneas increased the likelihood of conversion. American Academy of Ophthalmology EyeWiki: Ocular Hypertension () Why visual fields are still needed when the field is initially normal A normal field helps confirm that elevated pressure has not yet caused detectable functional damage. Repeated testing can later identify conversion from ocular hypertension to glaucoma. For a low-risk patient with normal optic nerves and stable pressure, visual field testing does not need to be performed at every visit. In contrast, a patient with very high pressure, a thin central cornea, a strong family history, older age, suspicious imaging, or a disc hemorrhage generally deserves closer surveillance. The National Institute for Health and Care Excellence recommends reassessment approximately every 18 to 24 months for treated ocular hypertension with controlled pressure and no detected conversion, but approximately every 6 to 12 months when conversion is uncertain or pressure control is inadequate. These intervals are guides rather than rigid rules. National Institute for Health and Care Excellence reassessment guidance () Practical approach for ocular hypertension A reasonable approach is: Obtain a reliable baseline visual field, often repeating it to confirm consistency. Document the optic nerve and retinal nerve fiber layer. Measure central corneal thickness. Estimate conversion risk using the full clinical picture. Repeat the field approximately every 12 to 24 months if risk is low and all findings remain stable. Test every 6 to 12 months when risk is moderate or high. Repeat sooner when pressure rises, the optic nerve changes, or a disc hemorrhage appears. Established Glaucoma Patients with established glaucoma benefit most consistSupport the show