Tag Archives: eye

Insight on Eyesight: Vision Correction While You Sleep

“You wore glasses before?”
“Yup.”
“Are you wearing contact lenses right now?”
“Nope, I only wear them when I sleep.”
“What?! You can do that?”

That was the typical response I got when people found that I wore contact lenses to sleep. At a very young age, I developed a common eye condition known as nearsightedness or Myopia; I could only see close objects clearly and objects far away appeared blurry. As my eyesight got worse at an abnormally fast rate, my optometrist (a doctor specializing in eye care) recommended me to wear “night lenses” to correct my vision, a practice known as Orthokeratology (Ortho-k).


Some Ortho-K lenses that I own
Copyright: Grace Lam 

How do you develop Myopia?

Myopia is typically an inherited condition and often develops in children ages 8-12.  This condition progresses very quickly at young ages due to the rapid growth of tissues in the eye while the eye is constantly elongating (growing in the forward-backward direction). Also, engaging in “close-up activities” such as reading and using the computer for extended periods of time can speed up the development of nearsightedness.

In order to see objects clearly, the image of the object must be focused on the retina. This is done by the lens in your eye (see image below), as it thickens when looking at close objects and flattens when looking at objects far away. According to researchers at the Ohio State University College of Optometry, the lens in patients with Myopia do not thin or flatten out like those of normal individuals. This causes the image to be focused in front of the retina rather than directly on it, thus resulting in a blurred image of objects that are far away.


The main areas of the eye affected in Myopia
by the National Eye Institute via Wikimedia Commons

How does Orthokeratology help?

The purpose of Ortho-k is to provide vision correction without the complications of surgeries and since changes cannot be made to the lens without opening up the eye, the shape of the cornea is altered instead (see image above). This is accomplished by wearing specially fitted contact lenses when sleeping.  As the cornea is also an important structure that helps focus images perceived by the eye, altering its shape effectively can compensate for the shortcomings of the lens and ultimately refocus the image back on the retina. As a result, myopic patients can once again see objects at close and far distances clearly. Check out the video below for more on Myopia and Orthokeratology.

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Youtube video by EyeContactOptometry

Research has shown that the use of Ortho-k lenses slow the progression of myopia, which is important to many myopic patients. I prefer night lenses because I can’t feel them when I sleep and when I take them off in the morning, I have 20/20 vision just like everyone else. Orthokeratology may not be the right treatment for everyone, but it can be advantageous for those who find glasses and day lenses inconvenient.

– Grace Lam

 

Hairy Eyeball?!

I think we can all agree that one of the most annoying occurrences that can happen in our day to day lives is when we get a hair in our eyes.  That annoying feeling, the constant blinking and the frantic rubbing to try and retrieve what feels to be the thickest hair you’ve ever made out of one of the most sensitive parts of our body.  Now, imagine how this unnamed 19-year old man from Iran felt when doctors found out he had hairs growing out of his eyeballs.

A Limbal Dermoid. Author: A Akram, via Flickr Creative Commons

Now, this isn’t something sudden that just appeared in this young mans eye, but is actually something that had been with him since he was born and gradually increased in size as he got older.  While not causing any physical pain, it had caused the young man to have vision defects as the effected eye saw 20/60  while the left eye saw 20/20.  It also caused him mild discomfort when blinking and what is reported as, “an intermittent sensation of the presence of a foreign body.”  From the above symptoms and conducting their own tests, doctors were able to identify the mass as a limbal dermoid, a very rare tumour mass found in about one in 10,000 patients made of special choristomatous tissue .

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Video from Youtube by user: 1OneMinuteNews.

Choristomatous tissue is made from the tissue of other body parts.  For example: the tissue in fat, sweat glands, muscles, teeth, cartilage, bone, and skin can all make up choristomatous tissue.  This explains how the young man has hairs growing out of his limbal dermoid, as the tissues in his tumour could be made of skin cells and also other cellular elements that skin cells are made along with such as hair follicles and sweat glands.

This mass can usually be found in 3 different places of the eye, all around the cornea.  It is either found just outside the cornea, slightly overlapping the cornea or in extreme cases , replacing the cornea itself!   The dermoid can vary in colour depending on the specific tissue found in the tumor mass but it is always firm and “fleshy” in nature and would help explain the discomfort the young man felt every time he closed his eye as well as the sensation of the presence of a foreign body.

Luckily, the 19 year-old man  didn’t have the horrific case of having his entire cornea replaced as the tumour was found bordering his cornea (see picture above).  This story also ends with a happily as doctors were able to successfully remove the 5mm by 6mm mass.  While doctors don’t expect improvement in his vision due to this removal, I know for sure he’ll be very happy not having hairs in his eye all the time.

– Ho-Hin Leung