Reading glasses (also known as presbyopic glasses) are optical aids used to correct presbyopia (commonly known as farsightedness due to aging). Presbyopia is a physiological phenomenon in which the eye's lens gradually hardens and the ciliary muscle function declines with age, leading to reduced accommodative ability, making it difficult to see nearby objects clearly. It is not an eye disease.
Key Definition Points
Essence: Reading glasses are convex lenses that converge light, allowing the image of nearby objects to focus accurately on the retina, thereby improving near vision.
Applicable Population: Usually begins to appear after 40 years of age, with prescription strength increasing with age (e.g., around +1.50D at 45 years old, around +2.00D at 50 years old).
Purpose: Mainly used for reading, looking at phones, sewing, and other close-up tasks. They should be removed when looking at distant objects (single vision lenses) or multi-focal lenses should be used.
Lens Types and Selection Recommendations
Common Types:
Single vision lenses: Only for near vision.
Bifocal lenses: Near vision at the bottom, distance vision at the top, but with image jump.
Progressive multifocal lenses: Clear vision at distance, intermediate, and near, with a natural appearance.
Material Selection:
Resin lenses: Lightweight, impact-resistant, recommended for daily use.
Glass lenses: Scratch-resistant but heavier and prone to breakage.
