What causes visual field defects?
Causes of visual field defects are numerous and include glaucoma, vascular disease, tumours, retinal disease, hereditary disease, optic neuritis and other inflammatory processes, nutritional deficiencies, toxins, and drugs. Certain patterns of visual field loss help to establish a possible underlying cause.
What causes inferior visual field defect?
Altitudinal visual field defect (VFD), which involves the loss of visual sensation in the horizontal half of the visual field, is caused mainly by anterior ischemic optic neuropathy (AION),1,2,3 or rarely by compressive neuropathy due to a tumor or aneurysm.
What causes nasal step defect?
Nasal step defects are caused by optic nerve disorders that affect the long, arching axons that originate temporal to the macula, entering the disc superiorly or inferiorly. A nasal step may begin as a small depression above or below (and respecting) the horizontal meridian in the nasal visual field (see Figure 3–8A).
What is the relevance of doing perimetry in a person suffering from glaucoma?
Hence, one of the most important clinical uses for perimetry is the detection of progressive damage in patients with established glaucoma. Unfortunately, detection of progressive visual field loss in eyes with glaucoma is a complex problem for which there is no gold-standard solution.
What causes superior visual field defect?
[6] The most common cause of the visual field defect is an ischemic stroke, comprising 69% of the cases. Most patients show homonymous hemianopia, but a third of the cases exhibit a superior quadrantanopia. Most lesions are localized in the occipital lobe, while 32% of lesions were found at the optic radiations.
What causes loss of peripheral vision in both eyes?
Difficulty seeing in one or both eyes is a common stroke symptom. A person may lose a portion of their peripheral vision after experiencing a stroke. Any stroke-related vision loss typically affects both eyes. Many conditions can affect your peripheral vision, causing you to lose all or parts of your sight.
What is nasal step glaucoma?
In practice the nasal step is an early and characteristic glaucomatous field defect like the isolated scotomas in the Bjerrum area, and it is easily detected and can be used as a sensitive marker in the follow up of glaucomatous damage.
What is the most accurate test for glaucoma?
Optical Coherence Tomography (OCT Scan) Can Diagnose Glaucoma Before All Other Tests. It is arguably the most accurate test in the world to assist our doctors in diagnosing glaucoma.
What do eye pressure numbers mean?
Eye pressure is measured in millimeters of mercury (mm Hg). Normal eye pressure ranges from 12-22 mm Hg, and eye pressure of greater than 22 mm Hg is considered higher than normal. When the IOP is higher than normal but the person does not show signs of glaucoma, this is referred to as ocular hypertension.
What is automated perimetry for glaucoma?
Standard automated perimetry is a useful tool for identifying and following many neurological conditions, as well as glaucoma and glaucoma suspects. While several devices are currently available, the following discussion will consider the use of the Humphrey Field Analyzer (HFA, Zeiss) as an example.
How is visual field testing performed in the evaluation of glaucoma?
Visual function assessment is integral to the evaluation and management of glaucoma. Visual field testing can be performed by various methods, including confrontation technique, amsler grid, tangent screen, kinetic perimetry, or static perimetry. This review will focus primarily on standard automated perimetry (SAP).
How often should we follow glaucoma patients with perimetry?
Following established glaucoma patients with perimetry is essential in determining if the current management is adequate or if treatment changes are needed based on the stability or progression of the visual field. The frequency of follow up will depend on the extent of the disease and the clinical course.
Do face masks cause visual field artifacts in glaucoma?
Unsuitable face masks can cause either visual field artifacts, which may be interpreted as glaucoma progression or low test reliability. Taping the face masks’ upper edges is an effective technique to prevent visual field artifacts and obtain good test reliability.