Vision problems and corrections
In absence of vision problems, the image of the observed object is formed directly on the retina. The situation of nitid vision which demands no correction is called emmetropia, which means excellent visual acuity and normal fields of vision.
Most common vision problems
The term “ametropia” refers to the situation when the image of the observed object is not formed in the correct form at the level of retina. It refers to a non-pathological problem of vision or, more precisely, the vision error or anomaly. Ametropia causes blurred vision which demands optical correction.
There are three types of situations:
• hyperopia or hypermetropia
Presbyopia is an inevitable situation after 40 years of age. It is caused by natural ageing of eye lens which gradually looses its flexibilty which therefore results in blurred or disturbed vision on near distances and/or tiredness when reading or working on close distances (computer). The tiredness can be manifested as headache, forced tearing, uncomfort when observing close objects, photophobia (the sensibility or intolerance to light).
These problems are most common ones but there are also others such as amblyopia, strabismus and hypovision.
How are vision problems corrected?
For a perfect eyesight, the visual correction helps to obtain the clear vision at the retinal level. The most common way to correct an ametropia is to wear corrective prescription eyeglasses. The choice of correct frame is, beside the aesthetics, also limited by the prescription of the patient.
The second solution is contact lens' wear. The new technologies of geometry and material fabrication are enabling the correction of astigmatism via contact lenses and correction of ametropia with contact lenses even with patients which have inadequate tear quality.
Finally, one of the ways to correct vision problems is refractive surgery which is indicated in some cases.