The eyeball's length being too short or too long is one of the cause of a refractive error is an irregularly shaped cornea. As people age, the ability to focus up close also becomes difficult because of the greater rigidity of the ageing lens.
Light focusses in front of the retina rather than on it. This means that far away objects are blurred and indistinct but nearby objects are clearly visible. Untreated myopia can cause headaches as a result of eyestrain, and squinting - the need to partially close the eyelid to try and see.
This is a condition where light fails to focus on a single point on the retina, resulting in blurred or stretched-out vision. Double vision, headaches are common symptoms of astigmatism.
This is a form of refractive error where light focuses behind the retina rather than on it. People with hyperopia can see objects at a distance but have problems focussing on things that are close up. This is a condition that is likely to worsen with age.
This is an age-related refractive error where the lens is no longer flexible enough to change shape and allow the eye to focus clearly on near objects.
