COMMON EYE CONDITIONS
What you need to know about eye conditions
Spectacle Prescription Types
Nearsightedness is caused by a longer than normal eye or steeper than normal cornea. This causes the light entering the eye to focus in front of the retina rather than directly on it. People with nearsightedness have difficulty seeing far off, but have little problems with near tasks.
Farsightedness is caused by a shorter than normal eye or flatter than normal cornea. This causes the light entering the eye to focus behind the retina rather than directly on it. People with farsightedness tend to have difficulty seeing up close with associated eye strain, yet might still have difficulty with distance tasks.
When the cornea has two different curves, one being steeper than the other, it is termed astigmatism. This oval or “football shaped” cornea causes light to focus at more than one point in the eye. This causes blurring at all distances and usually is associated with myopia and hyperopia.
Around the age of 40, the lens within the eye loses its flexibility and our ability to accommodate is lost. Accommodation refers to when the lens changes shape and thus changes our point of focus from distance to near. This condition is also known as “short arm syndrome” which everyone experiences at some point in their lives.
Contact Lens Related Problems
This degenerative disease results in a progressive thinning and bulging of the cornea into a volcano-like shape. This gradually causes the vision to become blurred and distorted which may not be correctable with glasses alone. People with keratoconus tend to have high amounts of nearsightedness and astigmatism as a result of the cornea’s irregular shape.
Contact Lens Overwear:
When not enough oxygen gets to the cornea as a result of wearing contact lenses longer than the recommended amount, irritation, redness and loss of vision can occur. This may lead to bacterial infections or corneal ulcers if it is not dealt with promptly. Contact lenses are a medical device and must be treated as such.
An ulcer results from bacteria infiltrating a damaged or compromised cornea. The bacteria creates a small divot on the cornea comparable to a pothole on a road. Corneal ulcers can be extremely painful and permanent loss of vision can occur. Contact lens wearers are at highest risk if they do not maintain proper cleaning, handling and disinfection of their lenses and cases.
Strabismus (Crossed Eye):
Most eyes focus at the same spot, sending slightly different perspectives to the brain so that we can judge depth and the three dimensions. Strabismus occurs when eye muscles cannot maintain both eyes on the same spot causing misalignment of the eyes or “turned eyes.”
Amblyopia (Lazy Eye):
Children do not have a fully developed visual system until the approximate age of 8. Some children suppress one eye to overcome high amounts of blur or double vision, thus not giving that eye a chance to develop properly. This results in a loss of vision that cannot initially be improved by glasses alone. In most cases the eye appears normal. The problem can be corrected if caught before the age of 8; however, it is difficult if not impossible to correct afterwards.
Illiteracy in Children Linked to Vision Problems:
The reason some children are struggling to read and write in school may be directly connected to not being able to see properly.
According to Dr. Troy Brady from the Leduc Eye Centre, 60 per cent of young children who are experiencing literacy problems are also experiencing vision issues. Five to 10 per cent of preschool children who are also experiencing literacy issues in school is also due to vision problems. Please read the full article here.