Long-Sightedness vs Short-Sightedness

Describes which is clearer to see.

Medical Term	Hyperopia	Myopia
Lay term	Long-Sightedness (plus), the “image” reaches past the the retina	Short-Sightedness (minus), the “image” reaches short of the retina
Meaning	Distant objects are clearer; difficulty seeing near objects clearly	Near objects are clearer; difficulty seeing distant objects clearly
Think of it as…	Hyper == “over”. I can see distant objects are more clear than near ones	== “to shut the eyes”. Literally squinting to see distant objects. I can see near objects clearer.
Cause	Eyeball too short or cornea too flat → light focuses behind the retina	Eyeball too long or cornea too curved → light focuses in front of the retina
Corrective Lens Type	Convex lens (converging), magnifying effect, plus power lens Dioptes Sphereeffect of lens: bring in closer to retina	Concave lens (diverging)
Lens Shape	Thicker in the middle	Thinner in the middle
Effect of Lens	Moves focal point forward onto the retina	Moves focal point backward onto the retina
Common Symptoms	Eye strain, headaches, blurry near vision	Squinting, blurry distance vision, headaches
Typical Onset	Often hereditary, may worsen with age	Often develops in childhood or adolescence
Lens Prescription	Positive numbers	Negative numbers