Showing posts with label vision. Show all posts
Showing posts with label vision. Show all posts

Monday, January 20, 2014

Inner and Outer Vision

The human body is a sensory process. Each of our sense organs takes in information that we imbue with meaning. For the month of May, get ready for a unique experience as we explore the function of each organ (think grade 9 biology refresher) and a kriya to create awareness and healing for that organ.

Lights, Camera, Action

When light hits the eye, the cornea helps the eye focus as light makes its way through. Behind the cornea are the iris, pupil, and anterior chamber. The iris is the colourful part of the eye. The iris has muscles attached to it that change its shape. This allows the iris to control how much light goes through the pupil. 

Inner and Outer Vision

The pupil is the black circle in the center of the iris, which is really an opening in the iris, and it lets light enter the eye. After light enters the pupil, it hits the lens. The lens sits behind the iris and is clear and colourless. The lens' job is to focus light rays on the back of the eyeball - a part called the retina. 

Your retina is in the very back of the eye. It holds millions of cells that are sensitive to light. The retina takes the light the eye receives and changes it into nerve signals so the brain can understand what the eye is seeing. 

Think of the optic nerve as the great messenger in the back of your eye. The rods and cones of the retina change the colours and shapes you see into millions of nerve messages. Then, the optic nerve carries those messages from the eye to the brain. 

Tears also keep your eye from drying out, keep the eye moist and provide expression through laughter and crying. 

Movement

Your eye muscles also need to be stretched. We tend to use our eyes in limited ways, staring at a computer screen, reading, driving and watching TV. For the most part we don't use our eye muscles fully. In this Kundalini Yoga Kriya for the eyes, you use all the muscles of your eyes, bringing circulation and a full range of motion available to your eyes. For optimal health, the eyes need exercise and rest.


Rest for the Weary

But what about eyestrain? The word is a bit of a misnomer, says Eli Peli, a professor of ophthalmology at Harvard Medical School. Peli says that vision happens in the brain, not the eyes; therefore, sitting at a computer isn't a strain for the eyes in the sense that it causes trouble for their muscles. Instead, the fatigue you feel is your brain asking for mercy. "The brain, in its smart way, projects fatigue onto the eyes, so you'll take a break."

Photo Credit: Conner Downey

Tuesday, November 19, 2013

What is a Cataract?

Cataract Pic 1If the human eye is compared to a camera, then a cataract can be considered as a cloudy lens in the camera, resulting in blurry images.

Normally, the crystalline lens is clear and transparent, allowing light to filter through to be perceived by the retina, which then sends the light signal through the optic nerve to the brain to be processed. A cataract, i.e. a cloudy lens, loses its transparency over time, and as a result, light rays are unable to pass through freely and the vision becomes foggy and blurry. Here is an excellent animation explaining cataract formation. 

cataract-example

What causes a Cataract?

Aging

I often tell my patients, "like wrinkles and aging spots, if we live long enough, we are all going to develop cataracts at some point of our lives." Over time, the proteins that make up the crystalline lens start to clump together and the lens eventually loses transparency. By the age of 80, more than half of the population will either have a cataract or already had cataract surgery. Although cataract is largely an age related issue. I am starting to see more and more young patients developing early cataracts in their 50's and even 40's. Below are a list of factors that contribute to early cataract formation.


Tobacco Smoking 

We all know smoking is bad for you. Examples include cancer, heart attack, stroke, and COPD, just to name a few. Adding one more to the list is BLINDNESS. It's a well known fact that smokers are 500% more likely to develop Age Related Macular Degeneration. Smoking also triples the rate of cataract formation. That's all the more reason to start quitting smoking. 


Diabetes

Many medical diseases increase the rate of development of cataracts. Among them, Diabetes Mellitus (DM) is probably the most common cause. DM is associated with 5-fold higher prevalence of cataracts. High blood sugar level causes the lens to swell up and loses its ability to focus light and image. However, as with most complications of diabetes, maintaining good control of your blood sugar levels will help reduce your risk. 

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UV Rays (including welding flashes)

The damaging effects of UV rays are well known. You can't see these invisible rays, but they certainly can damage the lens causing cataracts. Proper sunglasses are the key to protect your eyes especially if you spend long hours under the sun. Look for UV 400 on the labels for complete coverage of the UV rays. I like the old transition lenses poster, "these are your eyes without UV protection, any questions?"


Medication

Although cataract is largely an age related issue. More and more young patients are developing early cataracts in their 40's even 50's especially if they are on long term use of oral steroids. Crohn's disease, lupus, arthritis are just a few examples of systemic conditions that may require long term steroid treatment. If you are someone who is on oral steroids, be sure to see your optometrist regularly for cataract assessment. 


Trauma 

Trauma to the head and the eyes disrupts the protein in crystalline lens and will result in opacification of the clear lens thus leading to early cataracts. Patients who had prior accidents that resulted a blow to the head and eye area such as a bad fall, a motor vehicle accidents, and accident at work, are all at risk for developing traumatic cataracts. Also, patients who participate in high impact sports like football, wrestling, boxing...etc, are strongly recommended check their eyes regularly as well.


Treatment 

vi7_cataractsurgeryWhen the cataract is mature enough, cataract surgery can be performed to remove the cloudy lens. A standard cataract surgery usually takes 10-15 minutes. No hospital stay is needed, which means cataract surgery is done in an out-patient basis! There has been amazing technological advancement when it comes to cataract surgery in the last decade. It's a lot safer, a lot more precise, and with the newest surgical methods, patients will no longer need to depend on glasses!

When the cataract is removed, an artificial lens implant inserted to replace the natural crystalline lens. OHIP covers for the standard cataract surgery with the standard basic lens implant. However, the being said, there are numerous premium lens implant choices available. There are lenses that block UV rays to protect the retina; there are aspheric lenses which is optically more superior and gives you sharper vision; there are lenses that correct for astigmatism. Finally, multifocal lens implants allow patients to see both far and close up distances, essential eliminating the need for glasses after cataract surgery!

The newest advancement in cataract surgery is a procedure called Laser Refractive Cataract Surgery. It's a whole new level of precision and reproducibility in cataract surgery. It creates a clean incision and breaks up the lens fragment with laser, allowing the surgeons to remove the cataracts with utmost accuracy! It does come with a hefty price tag, but it certainly is an option worth contemplating. 


After Cataract Surgery

You will need eye drop medication to help the healing of the wounds, antibiotics to prevent eye infection, and anti-inflammatory to reduce the inflammation. After you are finished with all your eye drops, your surgeons will let you know when it's time to return to your Optometrist for regular follow-up. The prescription after the cataract surgery will be very different from what you have before the surgery, and Optometrist can give you a new and updated prescription. Most likely it will just be a simple reading prescription as the cataract surgery aims to eliminate your distance prescription. 

It is important to continue your annual eye exam with your Optometrist. We will continue to monitor if there is any changes to your eye health such as development of glaucoma and ARMD. Furthermore, secondary cataract can arise years after cataract removal, and it will require laser treatment to clean the film off the lens implant. So come in and have your regular eye examination and help fight low vision.

By: Rachel Lin, Vision & Eye Care Expert at AgeComfort.org Health Care Resource Centre

Tuesday, December 8, 2009

Keep things Clear with Low Vision Aids



Low Vision Aids Keep Things Clear!

As we grow older, our eyes are often the first things to give us trouble and we are also more likely to develop cataracts. A cataract is a clouding that tends to appear on the lens of the eye, eventually leading to loss in vision. Cataracts can happen at just about any age and vary in size, however they are most commonly associated with people over the age of 60. Glasses, various types of contact lenses and laser surgery are all good options depending on your needs but taking better care of our eyes, where possible, makes for a good first step. Low Vision Aids around the home will not only keep you from squinting, but also make life more comfortable!
Below is a small selection of what is out there to help aid the battle against fading vision.


LED Medicine Bottle Magnifier - This handy little magnifier makes reading pill bottles easy and accurate. If you take multiple medications, its easy to get them confused. This LED Magnifier provides 3X magnification of prescription labels and small print is illuminated by two ultra bright LED's.




Desktop Magnifier
- This inexpensive magnifier is perfect for reading newspapers, magazines, books or any small print. A popular and handy tool to have around the home or office. Viewing pictures in close detail also makes this magnifier popular as it has 3.5X power and features 2 separate lenses.



TV Reader
- Ok, now we were a bit skeptical of this at first but after using it, it really has its merits. The scroll over tool connects to your TV in seconds for and is perfect for really large viewing. Where we found this extremely handy was in a group setting. When you company over or during discussion groups, this allows the user to show everyone the topic of conversation and allows for maximum user control.


Magnifying Lamps - Whether its a table top or a floor standing magnifying lamp, this is a popular choice for just about anyone. These lamps are great for craft work, sewing and of course reading. Clamp to a table, sit next to your couch or stand next to your bed, the options are there. These also come in handy when looking at skin, cutting nails or doing anything that requires a little more attention to detail. When not being used for seeing clearer, these lamps provide ample light.


Like the rest of your body, your eyes can deteriorate as you get older. Taking small steps to make life easier and more comfortable will add to your day and to those around you. (Other Helpful Vision Aids)


“People only see what they are prepared to see.” - Ralph Waldo Emerson