How do lenses correct your eyes?

Lenses improve vision by altering the refractive power of the eye's natural lens due to refractive errors known as myopia (nearsightedness), hyperopia (farsightedness), and astigmatism. Here's an explanation of how different types of lenses correct your eyes:

1. Convex Lenses (Positive Lenses):

- Used for people with hyperopia.

- Thicker in the middle than at the edges.

- Converge (bend) light rays to focus them exactly on the retina (back of the eye).

- Corrects farsightedness by providing increased focusing power to converge light correctly on the retina.

2. Concave Lenses (Negative Lenses):

- Used for people with myopia.

- Thinner in the middle than at the edges.

- Diverge (spread out) light rays before they reach the eye.

- Corrects nearsightedness by slowing down the convergence of light to focus at the retina instead of in front of it.

3. Cylindrical Lenses (Toric Lenses):

- Used for people with astigmatism.

- Combination of spherical and cylindrical curves to adjust vision differently in different planes.

- Correct astigmatism by correcting focus for both near and far distances and compensating for the irregular curvature of the cornea or lens.

Lenses can be prescribed in various forms, including eyeglasses, contact lenses, or intraocular lenses (implanted lenses in the eye). The optimal lens type is determined by an optometrist or ophthalmologist based on a thorough eye exam, refraction tests, and individual preferences.