Monitoring tool

Amsler grid: testing your central vision at home

A grid you look at with one eye at a time. If the lines seem wavy, blurred or broken, your macula deserves an examination.

Start the test 3 steps · about 2 minutes

  1. 1Set the screen
  2. 2Observe
  3. 3Result

Setting your screen to its real size

A screen does not know its own size. Hold a bank card (or any card of the same format) vertically against the screen, then drag the slider until the blue rectangle is exactly the size of the card.

53.98 mm

No card to hand? Skip this step: the grid will use an average size, slightly less accurate.

Prefer it on paper? A grid 10 cm across, at actual size, to be viewed from 30 cm — one eye at a time, with your reading glasses.

A 10 cm grid: view it from 30 cm, one eye at a time, fixing your gaze on the central dot, with your reading glasses.

This test requires JavaScript. You can print a standard Amsler grid and view it from 30 cm, one eye at a time, fixing your gaze on the central dot.

What the Amsler grid shows — and what it does not

The grid explores about 20° of the central visual field, that is to say the macula. It brings out two signs: metamorphopsia, when straight lines appear wavy or distorted, and scotoma, when an area appears grey, blurred or absent.

Its limits are real and worth knowing. The test is subjective: the brain spontaneously fills in missing areas, which can mask a scotoma (perceptual filling-in). It does not see the peripheral retina, so neither an early detachment nor a tear. It screens for neither glaucoma nor cataract. A normal test therefore never replaces a fundus examination or an OCT.

Who is this test useful for?

Amsler grid monitoring is offered mainly to people followed for AMD, particularly when one eye is already affected and the other must be watched. It is also useful in diabetic retinopathy with macular involvement, epiretinal membrane, high myopia, or after certain retinal procedures.

It has no screening value in the general population without a risk factor: carried out in isolation, it worries more than it informs. Its proper use is regular, comparative monitoring, under the same lighting and at the same distance, by someone whose ophthalmologist has recommended it.

How to interpret what you see

  • The lines are straight and even, the grid is complete — a normal test today, on this eye.
  • The lines wave, bend or draw closer together — metamorphopsia. This is the most characteristic sign of a macular condition.
  • An area is grey, dark or empty — scotoma. The central part is the most significant.
  • The squares look smaller or larger on one side — micropsia or macropsia, which also reflect macular suffering.
Amsler grid as it may appear in age-related macular degeneration: the lines wave and tighten towards the centre, where a grey area masks part of the grid.
What a person with AMD may see: the lines wave and converge towards the centre (metamorphopsia), and a grey area masks part of it (scotoma). Compare with the intact grid of the tool above. Real distortions vary a great deal from one person to another: this image illustrates, it does not define what you should be looking for. Illustration by the National Eye Institute (NIH), public domain.

An abnormal result establishes no diagnosis. It indicates that an examination is called for, and how soon: promptly if the sign is new, the same day if it appeared suddenly.

Frequently asked questions about the Amsler grid

The rhythm is set by your ophthalmologist according to your situation. When monitoring AMD, a daily check or several a week is frequently proposed, because it is the comparison from one day to the next that has value — not the isolated test. Always carry it out under the same conditions: same lighting, same distance, same glasses.

Yes. If you wear a correction for near vision, keep it on: the test is done at reading distance. A blurred image caused simply by an uncorrected refractive error has nothing to do with a macular condition, and confusing the two falsifies the result. Do not wear sunglasses, and make sure the light is good.

Because one eye compensates for the other. A macular condition in a single eye can go completely unnoticed in binocular vision: the brain rebuilds the image from the good eye. That is why some cases of AMD are discovered late. The test only has value done eye by eye, the other carefully covered with the palm, without pressing on the globe.

No. The Amsler grid explores only the central 20° of the visual field. It does not see the peripheral retina, so neither a tear nor an early detachment. It does not screen for glaucoma, whose damage begins in the periphery, nor for cataract. It can also miss an early macular condition, because the brain spontaneously fills in small blind areas. Only a fundus examination and an OCT allow a conclusion.

Metamorphopsia that appears is a sign not to monitor at home: seek an ophthalmological opinion promptly, without waiting for a scheduled appointment. Several macular conditions, notably exudative AMD, are treated all the better for being caught early. If the distortion or the drop in vision appeared suddenly, within a few hours, go the same day to an ophthalmological emergency service.

Both are acceptable if the geometry is respected. What matters is not the size of the grid in centimetres but the angle it is seen under: a 10 cm grid viewed from 30 cm covers the same field as a 6 cm grid viewed from 18 cm. That is why this tool first measures your screen, then tells you the matching distance. A very bright screen, or one covered in reflections, remains less comfortable than a printed sheet: that is what the print button is for.

A new sign is to be shown, not monitored

Dr Moïse Tourabaly sees patients in consultation at the Cachan practice and at the Diabet’ Paris 13 practice for examination of the retina and the macula. A fundus examination and an OCT can state what the Amsler grid can only suggest.

Book an appointment on Doctolib — or browse the other tools and resources for understanding your sight.

Content written and reviewed by Dr Moïse Tourabaly, ophthalmologist. This tool is intended for information and monitoring; it establishes no diagnosis. A personalised ophthalmological opinion remains indispensable for any therapeutic decision.