These are (i) myopia or near-sightedness (ii) Hypermetropia or far – sightedness (iii) Presbyopia. Myopia is also known as near-sightedness.

What are the five eye defects?

Here, ophthalmologist Richard Gans, MD, explains the five most common conditions affecting your vision and shares tips for preserving your eyesight.

1. Cataract. …
2. Diabetic retinopathy. …
3. Macular degeneration. …
4. Glaucoma. …
5. Refractive errors.

05-Jan-2021

What are the defects of eye define?

The common defects of the eye are astigmatism, presbyopia, cataract, night blindness colour blindness and squint. Astigmatism is a defect in the eye or in a lens caused by a deviation from spherical curvature, which results in distorted images.

Is minus 5 eyesight bad?

Generally, the further away from zero (+ or -), the worse the eyesight. A number between +/-. 025 to +/-2.00 is considered mild, a number between +/-2.25 to +/- 5.00 is considered moderate, and a number greater than +/- 5.00 is considered severe.

What are the 3 vision or eye problems?

Most people who start needing glasses or contacts while they're young have at least one of three common vision problems: myopia, hyperopia, and astigmatism. These are all refractive errors, which means they're problems with the way the eyes focus light, rather than an eye disease.

How many eye defects are there?

There are three common eye defects, and they are(i) myopia or near-sightedness, (ii) Hypermetropia or far-sightedness, and (iii) Presbyopia. These defects are corrected by the use of suitable spherical lenses. In the article, we focus on myopia and its correction.

What are the causes of eye defects?

What Causes Eye Problems?

• Infection, allergy, vitamin deficiency, chemical irritants, genetics, smoking etc are some of the common causes of eye problems.
• Cataract — Etiology could be aging, hereditary, UV-Rays, dietary deficiency of vitamin E, C , B, and proteins.

Is negative 4 eyesight bad?

This is a fairly mild amount of nearsightedness. If you are -4.25, that means you have 4 and 1/4 diopters of nearsightedness. This is more nearsighted than -1.00, and requires stronger (thicker) lenses. Similarly, +1.00 would be a small amount of farsightedness and +5 would be more.