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Figure 1 - Humphrey field analyser. Humphrey field analyser (HFA) is a tool for measuring the human visual field that is commonly used by optometrists, orthoptists and ophthalmologists, particularly for detecting monocular visual field. [1] The results of the analyser identify the type of vision defect.
Confrontation visual field testing is an important part of a routine ophthalmological or neurological examination. It can be used for rapid and gross assessment of large-scale visual field problems due to ophthalmological or neurological diseases, such as homonymous and heteronymous hemianopias, quadranopsia, altitudinal visual loss, central/centrocecal scotoma etc. [1] [2] Test using a red ...
Visual field testing can be performed clinically by keeping the subject's gaze fixed while presenting objects at various places within their visual field. Simple manual equipment can be used such as in the tangent screen test or the Amsler grid. When dedicated machinery is used it is called a perimeter.
Swiss ophthalmologist Marc Amsler described the Amsler grid in the year 1945. It was the first functional test proposed to evaluate metamorphopsia. [4] He may have gotten the idea of the grid from Edmund Landolt, who used a similar small card with a grid pattern to be kept in the center of the visual field testing instrument perimeter. [3]
Diagnostic techniques like ophthalmoscopy, visual field test, optical coherence tomography, fluorescein angiography, multifocal electroretinography and electrophysiology may be used in diagnosing AIBSE syndrome. [2] Subjective measurement of blind spot enlargement is done using visual field testing. [4]
Testing the visual fields consists of confrontation field testing in which each eye is tested separately to assess the extent of the peripheral field. Normal visual field of a right eye. To perform the test, the individual occludes one eye while fixated on the examiner's eye with the non-occluded eye.
A scotoma is an area of partial alteration in the field of vision consisting of a partially diminished or entirely degenerated visual acuity that is surrounded by a field of normal – or relatively well-preserved – vision. Every normal mammalian eye has a scotoma in its field of vision, usually termed its blind spot.
A visual field test can differentiate between whether the reduced visual acuity is centered on the optic nerve or the fundus. Once a neurological problem has, therefore, been ruled out, the disorder's reduced visual acuity without visible fundus abnormalities may be misdiagnosed as optic neuritis, dominant optic atrophy, amblyopia, or ...