What Is Astigmatism?
Astigmatism refers to an irregular curvature of the cornea, the clear outer covering of the eye, which results in blurry vision.
The normal cornea directs light rays into the eye and accurately focuses them on the retina, which is the light-sensitive layer at the back of the eye. However, in the case of astigmatism, the corneal surface becomes irregular, causing the light rays to focus improperly on the retina.
Thankfully, vision issues caused by astigmatism can be effectively managed through various means, including the use of eyeglasses, contact lenses, surgical procedures, and Toric IOLs.
What Is Dysphotopsia?
Dysphotopsia is a patient observation of an optical distortion which can be noticed on occasion. It can be caused by an indirect side-light source. It is often caused by the lens design of the implant, for example: a square edge. The sharp edge of the implant is necessary to prevent clouding of the capsule membrane. There are new plastic materials with a lower index of refraction that may reduce this optical effect. There are also other designs that may reduce the chance of dysphotopsia occurring. In summary, the lens edge, stability and aberration correction are some factors to consider.