Archive for month: May, 2015

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Overnight Vision Correction

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Wouldn’t it be great if you could correct your eyesight and reduce your dependence on glasses or contact lenses — without having to undergo eye surgery? Orthokeratology (ortho-k) is the fitting of specially designed gas permeable (GP) contact lenses that you wear overnight. While you are asleep, the lenses gently reshape the front surface of your eye (cornea) so you can see clearly the following day after you remove the lenses when you wake up. GP contact lenses are not the same as the soft contact lenses that you may already wear; instead they are made of a firm, durable plastic that transmits oxygen.

How does an Ortho-K lens work?

The central portion of the lens fits closer to the eye than a standard contact lens exerting a gentle pressure. The outer part of the lens surrounds the central visual zone and is farther away from the cornea, allowing room for the cornea to change shape:

orthokeratology

 

Ortho-K lenses are custom made for each individual, but not everyone qualifies for this corneal refractive therapy. Two important factors that determine the candidacy for orthokeratology includes the curvature of the eye and the prescription. Your eye care practitioner will measure the exact shape of your cornea and prescribe lenses with the curvature, size, and corrective power that suit your eyes. Ortho-k is recommended for low to mild nearsightedness (-5 diopters or less).

When you begin to wear ortho-k lenses, you will likely have mild awareness of the lenses on your eyes until you fall asleep. Because the corneal reshaping effect is temporary, little risk is involved, and you can discontinue wearing the lenses at any time.

In summary:  no glasses, no daytime contacts, no surgery, 20/20 vision…no kidding!

 

Blog contribution by Eric Saidi, Optometry Intern, College of Optometry, Western University of Health Sciences.

Healing the Eye

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Our eyes are exposed to a wide variety of environmental conditions such as extreme weather, work environment and wearing contact lenses.  Sometimes these conditions may be so harsh that they stress the cornea, the outermost eye structure. Occasionally a patient will present in my office with an extremely compromised cornea. Such cases sometimes need a form of an eye band-aide to properly heal.

Enter the Amniotic Membrane

Such a bandage is an amniotic membrane which is derived from the placenta of an elective c-section. Human amniotic membrane is a unique collagenous membrane derived from the innermost submucosa of the placenta. Harvested under sterile conditions from the placenta of elective C-section after a full term pregnancy in medically cleared donors. This type of tissue has been used widely in the treatment of surface ocular diseases as it aids epitheliazation, reduces inflammation and fibrosis, prevents structural damage, and is also known to have some antimicrobial properties. It is used for a wide variety of ocular surface disorders such as: corneal ulcers, chemical or thermal burns of the cornea, and persistent epithelial defects.

An example used in our office is the ProKera Ring. It is a cryopreserved, sutureless amniotic membrane clipped to a plastic ring. ProKera is placed on the eye in a similar fashion as a large contact lens. ProKera does not require an operating room and can be performed in the office. Most importantly, it is reasonably well tolerated by patients.

Blog contribution by Lilia Babakhan, Optometry Intern, College of Optometry, Western University of Health Sciences.

 

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