The Amsler grid, used since 1945, is a grid of horizontal and vertical lines used to monitor a person's central

visual field The visual field is the "spatial array of visual sensations available to observation in introspectionist psychological experiments". Or simply, visual field can be defined as the entire area that can be seen when an eye is fixed straight at a point ...

. The grid was developed by

Marc Amsler Marc Amsler (born 5 February 1891 in Vevey, Switzerland – died 3 May 1968) was a professor of ophthalmology in the Eye Clinic at the University of Zurich. He took the position as professor of ophthalmology in Zurich in 1944. His predecessor ...

, a

Swiss Swiss may refer to: * the adjectival form of Switzerland * Swiss people Places * Swiss, Missouri * Swiss, North Carolina *Swiss, West Virginia * Swiss, Wisconsin Other uses *Swiss-system tournament, in various games and sports *Swiss Internation ...

ophthalmologist Ophthalmology ( ) is a surgery, surgical subspecialty within medicine that deals with the diagnosis and treatment of eye disorders. An ophthalmologist is a physician who undergoes subspecialty training in medical and surgical eye care. Followin ...

. It is a diagnostic tool that aids in the detection of visual disturbances caused by changes in the

retina The retina (from la, rete "net") is the innermost, light-sensitive layer of tissue of the eye of most vertebrates and some molluscs. The optics of the eye create a focused two-dimensional image of the visual world on the retina, which then ...

, particularly the

macula The macula (/ˈmakjʊlə/) or macula lutea is an oval-shaped pigmented area in the center of the retina of the human eye and in other animals. The macula in humans has a diameter of around and is subdivided into the umbo, foveola, foveal avas ...

(e.g.

macular degeneration Macular degeneration, also known as age-related macular degeneration (AMD or ARMD), is a medical condition which may result in blurred or no vision in the center of the visual field. Early on there are often no symptoms. Over time, however, som ...

Epiretinal membrane Epiretinal membrane or macular pucker is a disease of the eye in response to changes in the vitreous humor or more rarely, diabetes. Sometimes, as a result of immune system response to protect the retina, cells converge in the macular area as t ...

), as well as the optic nerve and the visual pathway to the brain. Amsler grid usually help detecting defects in central 20 degrees of the

. In the test, the person looks with each

eye Eyes are organs of the visual system. They provide living organisms with vision, the ability to receive and process visual detail, as well as enabling several photo response functions that are independent of vision. Eyes detect light and conv ...

separately at the small dot in the center of the grid. Patients with macular disease may see wavy lines or some lines may be missing. Amsler grids are supplied by

optometrist Optometry is a specialized health care profession that involves examining the eyes and related structures for defects or abnormalities. Optometrists are health care professionals who typically provide comprehensive primary eye care. In the Uni ...

s or from web sites, and may be used to test one's vision at home. The original Amsler grid was black and white. A color version with a blue and yellow grid is more sensitive and can be used to test for a wide variety of visual pathway abnormalities, including those associated with the retina, the

optic nerve In neuroanatomy, the optic nerve, also known as the second cranial nerve, cranial nerve II, or simply CN II, is a paired cranial nerve that transmits visual system, visual information from the retina to the brain. In humans, the optic nerve i ...

, and the

pituitary gland In vertebrate anatomy, the pituitary gland, or hypophysis, is an endocrine gland, about the size of a chickpea and weighing, on average, in humans. It is a protrusion off the bottom of the hypothalamus at the base of the brain. The ...

History

In 1869, Jacob Hermann Knapp described scotoma and metamorphopsia in traumatic maculopathy with choroidal rupture using horizontal lines. Similarly in 1874, Richard Forster demonstrated metamorphopsia using a square grid. Swiss ophthalmologist Marc Amsler described the Amsler grid in the year 1945. It was the first functional test proposed to evaluate

metamorphopsia Metamorphopsia (from , ) is a type of distorted vision in which a grid of straight lines appears wavy and parts of the grid may appear blank. People can first notice they suffer with the condition when looking at mini-blinds in their home. For examp ...

. He may got 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 A perimeter is a closed path that encompasses, surrounds, or outlines either a two dimensional shape or a one-dimensional length. The perimeter of a circle or an ellipse is called its circumference. Calculating the perimeter has several pract ...

Clinical significance

Amsler grid can be used in detecting central visual field defects in following conditions: *

Age-related macular degeneration Macular degeneration, also known as age-related macular degeneration (AMD or ARMD), is a medical condition which may result in blurred or no vision in the center of the visual field. Early on there are often no symptoms. Over time, however, som ...

: The grid will help detecting the progression of AMD from dry form to wet form. Chance of metamorphopsia is more in wet AMD compared to dry form. * Choroidal neovascular membranes: Choroidal neovascular membranes cause scotoma and metamorphopsia. It may be associated with many diseases like

, POHS, myopic macular degeneration, trauma etc. *

Central serous chorioretinopathy Central serous chorioretinopathy (CSC or CSCR), also known as central serous retinopathy (CSR), is an eye disease that causes visual impairment, often temporary, usually in one eye. When the disorder is active it is characterized by leakage of f ...

: CSCR Causes round or oval scotoma. *

Macular pucker Epiretinal membrane or macular pucker is a disease of the eye in response to changes in the vitreous humor or more rarely, diabetes. Sometimes, as a result of immune system response to protect the retina, cells converge in the macular area as t ...

: Macular pucker also known as an epiretinal membrane cause metamorphopsia and distortions in central field of vision. *

Cystoid macular edema Macular edema occurs when fluid and protein deposits collect on or under the macula of the eye (a yellow central area of the retina) and causes it to thicken and swell (edema). The swelling may distort a person's central vision, because the macul ...

: Due to macular edema, micropsia may occur. *

Glaucoma Glaucoma is a group of eye diseases that result in damage to the optic nerve (or retina) and cause vision loss. The most common type is open-angle (wide angle, chronic simple) glaucoma, in which the drainage angle for fluid within the eye rem ...

: Amsler grid is useful in detecting central field defects in moderate to severe glaucoma. *

Macular sparing Macular sparing is visual field loss that preserves vision in the center of the visual field, otherwise known as the macula. It appears in people with damage to one hemisphere of their visual cortex, and occurs simultaneously with bilateral homonymo ...

: Amsler Grid can be used to detect and accurately measure macular sparing.

Types

There are 7 types of amsler grid charts. All the charts measures 10 cm × 10 cm in size, which can be used to measure central 20 degree visual field when kept at a distance of 33 cm from the eye.

Chart 1

Chart 1 is the basic version, which is the most familiar and widely used chart among all the charts. In this chart the grid consists of 0.5 cm squares (each for 1° visual field), which totally measures 10 cm X 10 cm size. Most commonly grid is in white color with black background. Grid with black lines in white background is also available (see infobox picture).

Chart 2

Chart 2 is similar to chart 1, but it has diagonal cross lines, which assist correct fixation in case of central scotoma.

Chart 3

Chart 3 is also identical to chart 1, but color is red on black. Stimulating long wavelength foveal cones, this type of chart may help in detecting color scotomas and desaturation which may occur in toxic maculopathies, toxic optic neuropathies and pituitary tumors etc.

Chart 4

Chart 4 has no lines, only a random pattern of white dots in black background. It was intended to differentiate areas of scotoma and metamorphopsia.

Chart 5

Chart 5 has central white dot and horizontal white lines on black background 5mm apart, which allow detecting metamorphopsia.

Chart 6

Chart 6 is similar to chart 5, but lines and central dot is in black on white background. The lines near to fixation points are closer than the chart 5.

Chart 7

Chart 7 is similar to chart 1, however central squares are further divided into 0.5 degree squares.

Procedure

* Before starting the test, patient's near and distance vision should be corrected to normal. If the patient is wearing spectacles, testing should be done with glasses only especially if you have near glasses. * In a well illuminated room, ask the patient to hold the grid 12 to 15 inches away from the face. * Ask to cover one eye with hand or occluder and look directly at the center black dot. * While looking directly at the center dot, and observe the grid whether patient can see all corners and sides of grid. If any lines or areas look blurry, wavy, dark or blank mark that area in chart and consult

. * Follow the same steps with the other eye. * Always remember to keep the Amsler’s Chart at the same distance from the eyes each time you test. * This test can be self done at home also.

External links

amslergrid.org"Amsler Grid" Test
Free Android mobile app on Google Play

from Snellen eye chart

References

{{DEFAULTSORT:Amsler Grid Diagnostic ophthalmology