Most common visual problems are Short-sightedness, Long-sightedness, Astigmatism and Presbypoia. These refractive errors occur due to light not being focused onto the retina and are caused by shorter or longer eyeballs, shape of the cornea and ageing of the crystalline lens.
Short-sightedness (also known as myopia) is when distant objects appear blurred and closer objects appear clear. Nearsightedness occurs when the image is focused in front of the retina either due to the eyeball being too long or abnormalities in shape of the cornea or lens. The common signs and symptoms are: distant objects appear blurred, headaches, eyestrain, squinting. Nearsightedness can be corrected with glasses or contact lenses.
Long-sightedness (also known as hyperopia) is when distant objects appear clear and closer objects appear blurred. Farsightedness occurs when the image is focused behind the retina due to the eyeball being too short or abnormalities in shape of the cornea or lens. This in turn doesn’t allow the image to be focused onto the retina. The common signs and symptoms are: closer objects are blurred, headaches, eyestrain, squinting. Farsightedness can be corrected with glasses or contact lenses
Astigmatism occurs when the light is bent differently depending on where it comes into contact
with the cornea. The cornea in a normal eye is shaped like a football where the curvature is equal throughout. In astigmatism the cornea is shaped like a rugby ball where some parts are more steeper than others. This causes the image to be stretched and blurred. The common signs and symptoms are: headaches, eyestrain, squinting, blurred vision at all distances.Astigmatism can easily be corrected with glasses or contact lenses.
Presbyopia is a natural ageing occurrence (usually >40) which prevents you from focusing on closer objects. Presbyopia occurs due to the natural internal lens loosing its flexibility. Ageing also affects the muscles surrounding the lens which causes the light to be focused behind the retina. You can have other refractive errors (Nearsightedness, Farsightedness, Astigmatism) as well as presbyopia. The common signs and symptoms are: difficulty reading small print, having to hold your book or newspaper further away, headaches, eyestrain. Easiest way to correct presbyopia is to use reading glasses. If there are other refractive errors present then bifocals or varifocals can be useful.