Which type of lens is most effective in correcting myopia combined with astigmatism?

The sphero-cylindrical lens is the most effective choice for correcting myopia combined with astigmatism because it incorporates both spherical and cylindrical components in its design. Myopia, or nearsightedness, requires a spherical correction to adjust the focusing power of the eye, allowing for clear distance vision. Astigmatism, which results from an irregular shape of the cornea or lens, necessitates additional cylindrical correction to address the variation in curvature and refractive power in different meridians of the eye.

By utilizing a sphero-cylindrical lens, practitioners can effectively address both refractive errors simultaneously. The spherical part of the lens corrects the overall nearsightedness, while the cylindrical portion corrects for the specific astigmatic error, ensuring optimal visual clarity across various orientations. This combination is essential for patients who present with both myopia and astigmatism, making it the preferred choice in such cases.

In contrast, a spherical lens only corrects one type of refraction, a cylindrical lens addresses astigmatism but does not accommodate myopia, and a flat lens is not a standard type used for correcting these conditions. Hence, the sphero-cylindrical lens stands out as the