Which visual deficiency is characterized by unequal curvature causing glare?

Which visual deficiency is characterized by unequal curvature causing glare?

• A. Astigmatism
• B. Hyperopia
• C. Myopia
• D. Presbyopia

Answer: (A)

Unequal curvature of the cornea or lens causes light to be focused at more than one point on the retina, producing blur and glare. This uneven refractive power along different meridians is what defines astigmatism. In contrast, hyperopia (farsightedness) means light focuses behind the retina, myopia (nearsightedness) means it focuses in front of the retina, and presbyopia is the age-related loss of the eye’s ability to accommodate for near vision. Astigmatism is corrected with lenses that are cylindrical (toric), which balance the unequal meridional powers to yield a single clear focal point on the retina.

Unequal curvature of the cornea or lens causes light to be focused at more than one point on the retina, producing blur and glare. This uneven refractive power along different meridians is what defines astigmatism. In contrast, hyperopia (farsightedness) means light focuses behind the retina, myopia (nearsightedness) means it focuses in front of the retina, and presbyopia is the age-related loss of the eye’s ability to accommodate for near vision. Astigmatism is corrected with lenses that are cylindrical (toric), which balance the unequal meridional powers to yield a single clear focal point on the retina.