Ayurveda Notes BAMS

*Which of the following is not a refractive error?* A)Myopia B)Presbyopia C)Hypermetropia D)Astigmatism ANS : Presbyopia *Presbyopia is not classified as a refractive error because it is fundamentally different in cause and nature.* *Cause* : -Refractive errors (myopia, hyperopia, astigmatism) occur due to imperfections in the shape of the cornea, lens, or the length of the eyeball, causing light to focus improperly on the retina. -Presbyopia is an age-related condition caused by the gradual loss of elasticity in the lens and weakening of the ciliary muscles, reducing the lens's ability to change shape and focus on near objects. *Nature* : -Refractive errors are typically present from birth or develop during growth and are often static or change gradually over time. -Presbyopia is a natural part of aging, generally affecting individuals after the age of 40, regardless of their pre-existing refractive status. *Correction*: -Refractive errors are corrected by adjusting how light is focused on the retina using glasses, contact lenses, or refractive surgery. -Presbyopia is corrected using multifocal lenses, bifocals, or reading glasses that compensate for the lens's inability to focus on close objects, not by altering the eye's focusing power permanently. Note⚡ _Thus, presbyopia is a physiological condition due to aging, not a structural error in the refractive system of the eye_ .