Eye Glasses FAQs
What is 20/20 Vision?
2020 vision is normally defined as a measurement of your eyes site in a high contrast situation such as black against white. Normally the patient would be standing 20 feet from an eye chart and would be able to read letters that are approximately 9 mm tall. As a reference someone that has 20/40 vision would mean that you would need to stand 20 feet from the chart to have the same visual acuity for someone with normal vision standing 40 feet away. Since this type of vision tests only considers one facet of your vision, 2020 does not necessarily mean perfect vision as there are other factors involved.
What is Nearsightedness?
Nearsightedness is also known as myopia. People with this condition are able to see clearly for objects up close, the things at a distance are typically out of focus. Myopia has a tendency to become progressively worse especially during childhood years were there may be a lot of reading or close work. This condition seems to stabilize after age 40 and rarely progresses much beyond that point. It is not uncommon for myopia patients to also have astigmatism.
What is Farsightedness?
Farsightedness is a condition that is also known as hyperopia. People with this condition are usually able to see objects far away with reasonable clarity. However they usually have trouble focusing on objects that are close, which would usually appear blurry. Sometimes this condition is worse at night and they often produce aching eyes or headaches due to eyestrain. Your eye care professional can probably diagnose you with a thorough eye examination.
What is Astigmatism?
Astigmatism is a vision problem is caused by an irregularly shaped eye surface which interferes with how the eye focuses light. Astigmatism can cause varying degrees of focus depending on the condition. For example the light rays entering the eye do not convene in on a single focal point on the retina which would be necessary to produce clear vision. In this situation multiple focal points occur either in front of the retina or behind it or sometimes both. Astigmatism is notnecessarily an eye disease or health problem and can be easily corrected with eye glasses or contact lenses.
What are Bifocals? Do I Need to Wear Them?
Bifocals use two different optical correction powers in the same lens. Usually in this scenario, the upper portion of the lens is generally used for distance vision in the lower area of the lens would be used for focusing on objects that are near such as reading. Bifocals are often prescribed for patients with presbyopia, a condition that is common in people over the age of 40 that makes it difficult to focus on objects that are close.