{"id":30090,"date":"2024-10-25T12:30:48","date_gmt":"2024-10-25T10:30:48","guid":{"rendered":"https:\/\/eyelaser.at\/diopters-the-unit-of-measurement-for-refractive-power-what-the-values-mean-diopter-table\/"},"modified":"2025-08-07T23:06:33","modified_gmt":"2025-08-07T21:06:33","slug":"diopters-the-unit-of-measurement-for-refractive-power-what-the-values-mean-diopter-table","status":"publish","type":"post","link":"https:\/\/eyelaser.at\/en\/diopters-the-unit-of-measurement-for-refractive-power-what-the-values-mean-diopter-table\/","title":{"rendered":"Diopters: The unit of measurement for refractive power & what the values mean (diopter table)"},"content":{"rendered":"\n

Have you ever thought about what the numbers on your spectacle pass<\/strong> mean? Or why the diopter values<\/strong> for contact lenses<\/strong> and glasses<\/strong> are different? Diopters<\/strong> are more than just a number – they describe how severe your defective vision<\/strong> is and how it can be corrected. In this blog, we take a deep dive into the world of diopters: <\/p>\n\n

What exactly does the diopter value<\/strong> say about your vision<\/strong>? How do short-sightedness<\/strong>, long-sightedness<\/strong> and astigmatism<\/strong> differ in their values? And how is it actually measured whether you need glasses and contact lenses or perhaps even laser eye treatment<\/strong>? What are the diopter limits for laser eye surgery \/ lens surgery? <\/p>\n\n

Here you will find the answers – diopters explained simply!<\/p>\n\n

What are diopters? – The unit of measurement for defective vision <\/h2>\n\n

Diopters (abbreviated as dpt<\/strong>) are the unit of measurement used to describe the refractive power<\/strong> of optical lenses. In the context of the eye<\/strong> and defective vision<\/strong>, diopters indicate how strongly a spectacle lens<\/strong> or contact lens<\/strong> must refract light in order to correct vision. The term diopter<\/strong> therefore describes the ability of a lens to focus light rays in such a way that they produce a sharp<\/strong> image on the retina<\/strong> of the eye. The exact determination of diopters is essential for the precise fitting of spectacle lenses in ophthalmic optics.<\/p>\n\n

An eye with normal vision<\/strong> has a refractive power of around 60-65 diopters<\/strong>, as the lens of the eye and the cornea<\/strong> refract the light so that it is focused on the retina. However, if the refractive power of the eye is too weak or too strong, this results in short-sightedness<\/strong> (myopia<\/strong>)<\/a> or long-sightedness<\/strong> (hyperopia<\/strong>)<\/a>. This is where negative values<\/strong> for myopia and positive values<\/strong> for hyperopia come into play. <\/p>\n\n

A lens with a power of 1 diopter<\/strong> changes the focal point of light by exactly one meter. Higher diopter values<\/strong>, such as 13 diopters<\/strong>, indicate a more severe visual defect, which often needs to be corrected with thicker glasses<\/strong> or specially adapted contact lenses<\/strong>.<\/p>\n\n

Diopter table: An overview of the diopter values <\/h3>\n\n

Here is a diopter table<\/strong> that provides an overview of the typical diopter values<\/strong> for the correction of myopia<\/strong>, hyperopia<\/strong> and other visual defects<\/strong>:<\/p>\n\n

Diopter value (dpt)<\/strong><\/th>Poor eyesight<\/strong><\/th>Description<\/strong><\/th><\/tr><\/thead>
0 dpt<\/td>Normal vision (emmetropia)<\/td>The eye<\/strong> has normal vision<\/strong> and does not require correction. Sharp vision<\/strong> is possible.<\/td><\/tr>
+0.25 to +2 dpt<\/td>Slight farsightedness<\/strong>(hyperopia)<\/td>Slight difficulty focusing on nearby objects. Can be corrected with reading glasses<\/strong>. <\/td><\/tr>
+2 to +5 dpt<\/td>Medium farsightedness<\/td>Significant loss of near vision, often also difficulties in reading without a visual aid<\/strong>.<\/td><\/tr>
+5 dpt and more<\/td>Severe farsightedness<\/td>Severe near vision problems that need to be corrected with strong spectacle lenses<\/strong> or contact lenses<\/strong>.<\/td><\/tr>
-0.25 to -3 dpt<\/td>Slight short-sightedness <\/strong>(myopia)<\/td>Slight problems seeing distant objects clearly. Glasses<\/strong> or contact lenses<\/strong> with negative values<\/strong> necessary.<\/td><\/tr>
-3 to -6 dpt<\/td>Medium myopia<\/td>Vision at medium and long distances is blurred. Stronger correction is required. <\/td><\/tr>
-6 dpt and more<\/td>Severe myopia<\/td>Severe short-sightedness<\/strong>, objects are very blurred in the distance. High diopter values<\/strong> often require special lenses<\/strong>.<\/td><\/tr>
\u00b10.25 to \u00b12 dpt<\/td>Astigmatism<\/strong>(curvature of the cornea)<\/td>Distorted vision due to an uneven cornea<\/strong>. Can occur with both short-sightedness and long-sightedness<\/strong>. <\/td><\/tr>
+2 to +3 dpt<\/td>Presbyopia (presbyopia<\/strong>)<\/td>Difficulty with near vision due to the natural ageing process. Often needs reading glasses<\/strong>. <\/td><\/tr><\/tbody><\/table><\/figure>\n\n

This table provides a general overview of how diopter values<\/strong> affect vision<\/strong>. Values from +20 diopters or<\/strong> -20 diopters<\/strong> are very rare and indicate extreme visual defects, which are often corrected by special visual aids<\/strong> or even surgical procedures such as laser eye surgery<\/strong>. <\/p>\n\n

How does defective vision develop? Relationship between diopters and visual acuity <\/h2>\n\n

Visual defects<\/strong> occur when the eye is unable to focus the incoming light correctly on the retina. This is usually due to a malformation of the eyeball<\/strong>, an uneven cornea<\/strong> or an altered refractive power<\/strong> of the lens<\/strong>. Accurate measurement of the diopters is crucial to determine the extent of the visual defect.<\/p>\n\n

Short-sightedness and long-sightedness: myopia and hyperopia explained <\/h3>\n\n

With short-sightedness<\/strong>, the eyeball is too long or the refractive power of the eye is too strong, so that light is focused in front of the retina. As a result, distant objects appear blurred<\/strong>, while near objects are seen clearly. The correction is made using negative diopters<\/strong>, which redirect the light so that it hits the retina correctly again. <\/p>\n\n

With long-sightedness<\/strong>, the eyeball is too short or the refractive power is too weak. This means that the light is focused behind the retina, making it difficult to see close up. Positive diopter values<\/strong> help to focus the light more strongly and thus improve vision. <\/p>\n\n

Astigmatism and the diopter value <\/h3>\n\n

Astigmatism<\/strong> is caused by an unevenly curved cornea<\/strong> or lens, which causes light to be refracted in different directions. This leads to distorted or blurred vision, both near and far. Astigmatism<\/strong> and short- or long-sightedness<\/strong> often occur together and require special visual aids<\/strong>. Diopters also play an important role in determining the exact correction required for astigmatism. <\/p>\n\n

Presbyopia: when the lens becomes inflexible<\/h3>\n\n

With increasing age, the lens<\/strong> loses flexibility, which means that the eye has problems focusing on objects close up. This so-called presbyopia<\/strong> usually occurs from the age of 40 and is corrected with reading glasses<\/strong> or special progressive lenses<\/strong>. <\/p>\n\n

Measurement of diopters: What the optician and ophthalmologist do <\/h2>\n\n

Measuring diopters<\/strong> is an important step in determining defective vision<\/strong> and prescribing the right visual aid<\/strong>. Both opticians<\/strong> and ophthalmologists<\/strong> use special procedures and devices to determine visual acuity<\/strong>. The diopters determined provide precise information about how strongly a spectacle lens must refract light. Here are the most important steps: <\/p>\n\n