Also know as Hyperopia or Hypermetropia, this is an optical defect causing difﬁculty focusing on near objects. To correct this defect, a convex lens will be required to realign the optics of the eye and restoring vision. If the optical defect is very extreme, focusing on objects at any distance can be difﬁcult.
This condition is often confused with Presbyopia, a different condition that only affects near vision.
Also know as Myopia, this is an optical defect causing difﬁculty focus on distance objects.
If the optical defect is very extreme, focusing on objects at any distance will be very difﬁcult. To correct this defect, a concave lens will be required to re-align the optics of the eye and restoring vision.
Astigmatism is an optical defect where there is more than one focus point due to irregular curvature on either or a combination of the cornea and crystalline lens. Therefore the curvature is more oval, like a rugby ball instead of a round football.
Astigmatism can be present with longsightedness or shortsightedness. To correct this defect a toric lens is required, which can be in a combination of a convex or concave lens to correct the longsightedness or shortsightedness respectively.
As you get older, the crystalline lens in the eye becomes less elastic. This hardening of the lens reduces the ability to change your focus from far to near. These changes can cause symptoms like difﬁculty to read books or threading a needle.
The severity of your symptoms can be affected by your distance vision, whether you are longsightedness or shortsightedness.