What type of lens design is often used to correct astigmatism in contact lenses?

Bitoric lenses are specifically designed to correct astigmatism by accommodating the varying curvature of the cornea. Astigmatism occurs when the cornea is not perfectly spherical, leading to distorted or blurred vision at multiple distances. Bitoric lenses provide two different radii of curvature—one for the meridian that requires correction for nearsightedness or farsightedness, and another for the meridian that corrects for astigmatism. This dual curvature allows for precise fitting and can enhance visual clarity for individuals with astigmatism.

In contrast, spherical lenses have a consistent curvature throughout, making them suitable primarily for myopia (nearsightedness) or hyperopia (farsightedness) but not effective for addressing astigmatism. Similarly, aspherical lenses offer improved optics for some vision impairments by reducing peripheral distortion but do not specifically target the unique requirements of astigmatism. Symmetrical lenses don’t apply to astigmatism correction as they are typically uniform in design, lacking the tailored shape necessary for the varying refractive needs presented by astigmatism. Bitoric lenses stand out as the most effective choice for addressing this particular type of vision irregularity.