A relatively common condition, astigmatism occurs where there is a curvature of the cornea and or crystalline lens. Viewing ability becomes blurry at any distance whether near or far.
A common misconception is that this requires a gas permeable (hard) lens, when in reality gas permeable, hybrid and soft contact lenses are all able to correct an astigmatism successfully.
Otherwise referred to as farsightedness, with hyperopia, objects at a distance are clear, whereas objects up close are blurry. A “plus lens” allows a clear image to be seen at any distance.
Myopia is more commonly known as nearsightedness, a condition in which distant objects are blurry or out-of-focus. If you find yourself squinting or literally have “your nose stuck in a book,” you may be nearsighted. Fortunately a simple correction using a “minus lens” allows light rays to be properly focused and a clear, sharp image to be seen.
Presbyopia is the lack of ability to bring near objects into focus as a result of normal age-related changes in the crystalline lens of the eye.
Initially the crystalline lens, which is located behind the pupil, is flexible and allows the eye to focus on objects close to the eye. As the eye ages this lens becomes less flexible and close items cannot be seen clearly, unless moved away from the eye. A “plus lens” is used to correct presbyopia. Most people will become aware of this difficulty around the age of forty.
Cataracts are like having a magnifying glass, and then covering it in wax paper. The crystalline lens becomes increasingly opaque, decreasing both visual clarity and contrast. Cataracts can be removed with surgery and the solid lens is replaced with a clear, artificial lens. There are several classifications of cataracts, including:
- Congenital: Present at birth
- Hypermature: The lens has become either solid, or shrunken and liquefied
- Incipient: Any cataract in its early stages
- Mature: The lens is completely opaque
- Senile: A hard opacity of the lens occurring with increase in age
- Traumatic: Lens becomes opaque due to injury
Glaucoma is a vision loss caused by damage to the optic nerve, which acts like an electric cable, sending images to the brain. Reduced vision often begins at the edges, or periphery of your vision, and moves towards the center. Pressure inside the eye often increases in a patient with glaucoma. This is closely monitored, along with the health of the optic nerve. There is yet no cure for glaucoma, but treatment is available and early detection is helpful in preserving vision. Some risk factors include:
- Individuals over 65 years of age
- Family history of glaucoma
- African-Americans over 40 years of age
- Past serious eye injury
Macular degeneration affects both central and color vision. There are two forms of macular degeneration. The wet form, affects one in ten patients and is a more severe form of degeneration. The dry form, which is the thinning of the macular tissue and affects nine out of ten patients. Macular degeneration increases greatly with age. Risk factors include:
- Family history
- Cardiovascular disease
- Light-colored eyes
A completely natural process, vitreous degeneration is a fancy name for occasional flashes of light and “floaters” which occasionally come across your vision field from time to time. A regular occurrence or increase of “flashes and floaters” warrants a retinal evaluation in order to rule out retinal tears or detachment.
3D Eye Library™
Scroll through our 3D Eye Library to discover more educational information about the overall health of your eyes.
Learn about the structures of the eye, ocular diseases and treatment options. Topics covered include: macular degeneration, glaucoma, keratoconus, conjunctivitis, contact lens care, and general exam information.