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Tag: eye health

Posted on by Dr. Sherman Tung

20/20 Vision

When having an eye exam done you might have been told that you have 20/20 vision, but what exactly does that mean? To put it simply, having 20/20 vision indicates that at a distance of 20 feet, you are able to see the smallest letters that should be seen at 20 feet. If you have 20/40 vision, it indicates that you need to be at 20 feet to see what a person with 20/20 vision can see at 40 feet. On the other hand, if you have 20/15 vision, you can see at 20 feet what a person with 20/20 vision can see at 15 feet.

How do we measure our visual acuity?

There are many ways to measure a patient’s visual acuity, but the most common way is through using a Snellen chart that presents with numerous lines of letters above one another. Letters found at the top of the chart are larger and easier to see but become smaller and difficult to read as you move down the chart. Patients are tested by covering one eye and reading the letters from top to bottom at which point they repeat these steps while covering the other eye. Afterwards, patients will use both eyes together to determine the lowest line they are able to read clearly.

Posted on by Dr. Sherman Tung

How do my eyes adjust to different lighting?

Photo by Agence Olloweb on Unsplash

Our eyes are incredible at adapting to different lighting conditions. This is done through the iris and pupil of the eye. Our pupils are the dark hole at the front of the eye which allows light to enter and form an image on the back portion of our eye. This pupil size is controlled by muscles found on the iris, which is the coloured portion surrounding the pupil. In bright sunlight, our pupils will begin to constrict, allowing less light to enter into the eye. On the other hand, when we are in a dark room our pupils will become bigger and increase the amount of light getting into the eye.

credit: https://www.sciencelearn.org.nz/resources/50-how-the-eye-focuses-light

Once the light enters through our pupil, it hits the back of our eye called the retina. The retina has two types of photoreceptors called rods and cones. Rods are responsible for night time vision and cones are responsible for day time vision. When we are in a dark room, rods are the ones that let us see.

Dark adaptation

The reason you are momentarily blind in the dark when going from a well-lit room is because it takes some time for our eyes to adjust. This is referred to as dark adaptation. During this period, the rod receptors are the key players to fully adapt and return vision to normal.

Posted on by Dr. Sherman Tung

Is it okay to buy glasses online? Do I really need an optometrist/ optician?

Photo by wu yi on Unsplash

When considering whether to buy your glasses online, at first it may seem more convenient and likely less costly. But the prescription given to you by your optometrist is only one piece of information that will determine how effective your glasses will be in improving your vision. Let’s consider the pros and cons:

Pros of buying online:

  • Wider selection of styles and colors
  • Many choices between different websites
  • Often can save on cost (but more on that later)

Cons of buying online:

  • You miss out on having a trained professional aid you in ensuring your glasses are the right fit in
    terms of comfort and effectiveness
  • Quality control of frames may often be sacrificed to maintain that low price you see online
  • Specific measurements such as PD, finding the best optical center, and measurements for
    progressives will either often be wrong or not available for online retailers
  • Prescription issues in general occur much more commonly when ordered online as opposed to
    in person

What could initially be seen as a way to save time and money in the first place may end up more costly for both in the long run if any of the above issues occur. In addition, common complaints with improperly selected glasses may include: headaches, fatigue, nausea/dizziness, eyestrain, glasses slipping off the nose, and pain/pressure marks on your nose/around the ears. Those with high prescriptions, children, complicated prescriptions, and multifocal prescriptions should especially consider in person options as opposed to online.

Posted on by Dr. Sherman Tung

What reading under the covers does to your eyes

Image by Freepik

While it is untrue that reading in the dark will permanently damage your eyes it can cause shorter term issues. You may have to strain harder which can lead to headaches, irritated eyes, general eye fatigue. If this is coupled with other existing issues you may also experience blurry vision or even double vision temporarily. The extra strain and need to focus may also prevent you from blinking as often, leading to dry eye symptoms.

Posted on by Dr. Elisa Xiao

Will I Develop Presbyopia?

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Presbyopia is the gradual loss of your eyes’ ability to focus up close. This tends to start around your early 40s and progresses until around the age of 65. You may notice starting to hold reading material further away to keep it clear, blurry vision at previously normal reading distance, eyestrain or headaches after extended periods of reading.

Managing presbyopia

Depending on your health, lifestyle and preferences, your eye care specialist may suggest any of the following methods to correct presbyopia:

  • Eyeglasses in the form of readers, bifocals, progressives, etc.
  • Contact lenses, typically multifocal or monovision
  • Surgeries
  • Eye drops such as Vuity

Can I prevent presbyopia?

You can’t prevent presbyopia since it’s a part of the natural aging process. You can, however, take steps to protect your eye health. This includes:

  • Wearing sunglasses to shield your eyes from harmful ultraviolet (UV) rays.
  • Eat foods rich in nutrients that promote eye health, including vitamin A, vitamin C, vitamin E and lutein, and Omega-3s
  • Improve lighting in work areas
  • Increase font and change contrast in smart phones or computer devices etc.
Posted on by Dr. Sherman Tung

Can I Wear my Contact Lenses for Longer than I’m Suppose to?

Photo by Lensabl on Unsplash

If I’m careful with cleaning, can I wear my dailies for more than 1 day?

Daily disposables are thinner and are made of a material that is not made to resist bacteria and buildup. So, if you try to clean or disinfect these thin lenses you may actually create breaks instead, further increasing infection risk. Using a compatible brand of soft contact lens rewetting drops to hydrate your daily disposables for comfort is acceptable.

What happens if I wear dailies for more than 1 day?

Wearing daily disposable contact lenses more than once puts you at risk for discomfort, dryness, corneal ulceration/scarring, and eye infections.

Differences between Dailies, Bi-weeklies, and Monthlies

Dailies are worn only for one day and discarded when you remove them, these are typically very thin and have a high water content. Natural deposits from your eyes build up easily on their surface, and they cannot be reused. This could mean more convenience but also, depending on how often you replace them, more costly.

Monthly or bi-weekly contact lenses are thicker than daily disposables. The thicker composition makes them more durable and long-lasting, and they are usually more resistant to drying out. However, they must be disinfected regularly in order to ensure healthy wearing.

Posted on by Dr. Elisa Xiao

Are optometrists, opticians, and ophthalmologists the same?

Image by macrovector on Freepik

As a patient, understanding the role and the services offered by each of these three eye care
professionals will help you get the specific eye care you need, know what questions to ask, and work
with your health care provider to determine appropriate solutions that work for you.

Optometrists

Optometrists perform eye exams to check the overall health of your eyes and issue prescriptions for contact lenses or glasses, or low vision devices. The optometrist will perform a number of tests including visual acuity (how well you can see letters/symbols from a distance and near), your ability to see colour, your depth perception, retinal health, the pressure inside your eyes etc. The optometrist may use eye drops to dilate your pupils to help them detect conditions such as glaucoma, cataracts and macular degeneration and more.

Ophthalmologists

An ophthalmologist is a medical doctor who specializes in eye health and related diseases. Ophthalmologists undergo post-graduate training that qualifies them to treat eye diseases both medically and surgically. Ophthalmologists provide surgical solutions to common eye problems such as cataracts, and monitor eye conditions like glaucoma as well as perform laser corrective surgery.

Opticians

Opticians fit, adjust and dispense prescription and non-prescription eyewear. They do not perform eye exams nor prescribe but can assist with filling your prescription, adjusting glasses, and ordering new/replacement contact lenses.

Posted on by Dr. Melody Tong

Are You Ready For Your Eye Exam?

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Having an annual eye exam is a great way to not only take care of your eyes but your overall health as well. Eye exams can detect early signs of conditions such as diabetes and high blood pressure. Here are some tips to help you make the most of your next visit!

What to think about:

  • Have I noticed any eye problems such as blurry vision, flashes of light, floaters, redness, or double vision?
  • Are my daily activities being affected by my vision?
  • How do I take care of my contact lenses or glasses
  • Have I had any surgeries or injuries in my eyes that I could let the doctor know about?
  • Any family history of eye conditions such as glaucoma?

What to bring:

  • Your current glasses or contact lenses even if you have multiple pairs for different tasks
  • A list of your medications/supplements you are taking
  • Have someone who can drive you home or a method of transportation ready for if you have your eyes dilated. This happens often in yearly eye exams and can make you sensitive to light and have blurry near vision (~4-6 hours)
  • Vision and health insurance information

Questions to ask:

  • Differences between contacts and glasses for you and how this compares to surgery options as well?
  • If anything has changed in my ocular health since the last visit?
  • What any symptoms you may have mean and what you can do to prevent them from getting worse or resolve?
  • When should I return for my next visit?

Posted on by Dr. Elisa Xiao

Are Cosmetic (Color) Contact Lenses Safe?

photo credit: drtavel.com

Cosmetic contact lenses or colored contact lenses may seem harmless but can lead to severe eye problems or loss of vision if not fit by an eye specialist. You need to have a prescription for contact lenses as they are deemed medical devices by the U.S. Food and Drug Administration (FDA). Non- prescription contacts can create problems due to issues such as poor fitting or unclean packing/creation.

When contact lenses not specifically fitted and sized for your eyes are worn, the cornea may be scratched, potentially leading to the following:

  • Painful corneal abrasion
  • Decreased vision
  • Redness, soreness, itching
  • Sensitivity to light
  • Allergic reactions
  • Corneal ulcers

Eye infections are also very common in non-prescribed contact lenses and may lead to the following:

  • Persistent eye pain
  • Decreased vision
  • Sensitivity to light
  • Discharge from the eye (this could be green/yellowish mucus like or more watery)

Discussing your options and proper contact lenses hygiene with an eye care professional, having the
proper measurements of your eyes taken, and getting a valid prescription is an easy way to avoid these
potentially life changing complications.

Posted on by Dr. Elisa Xiao

Is it Blepharitis?

Blepharitis is when you have inflammation of your eyelids. Sometimes the cause is from skin conditions
such as dandruff or rosacea while other times the cause could be from overpopulation of bacteria or
even parasitic mites called demodex.

Image from: https://www.allaboutvision.com

Some signs or symptoms you may be experiencing include:

  • Red, swollen eyes
  • A gritty or burning sensation in your eyes
  • Excessive tearing or itching
  • Dry eyes or crusted eyelashes
  • Increased sensitivity to light
  • Dandruff-like scales on the eyelashes
  • Blocked eyelid glands
  • Eyelashes may fall out of be misdirected inwards causing damage to the cornea
  • Increased risk of infection

So what can you do?

With so many varying signs and possible causes it is important to have a comprehensive eye exam in
order to determine the type of blepharitis you may have. Once determined a specified treatment plan
can be made to manage the condition. Luckily, in many cases taking care of your eyelid hygiene,
whether in office or at home, is a simple enough method in keeping the symptoms of blepharitis at bay
and from affecting your daily life. It is important to remember that this will likely be a long term plan.
Treatments in office or at home may help jump start your recovery, but proper hygiene must be
maintained overtime, or the symptoms of blepharitis may return.

At-home ocular hygiene tips:

  • Frequently wash your the scalp and face
  • Warm compresses to help soften crust and help unclog oil glands present in eyelids
  • Use artificial tears (often helpful when placed in the fridge to bring down inflammation)
  • Limit or stop using eye makeup during treatment, as it makes lid hygiene more difficult.
  • Nutrition changes/supplements such as omega-3s

More severe cases may warrant in-office treatments:

Photo credit: Eye Health Shop, 2023

  • Intense Pulsed Light therapy, involving the application of bright red light pulses to your eyelids
  • BlephEx®, which involves cleaning your eyelid margins with microblepharoexfoliation.
  • Lipiflow or other dry eye focused treatments may be used concurrently
  • Depending on your case antibiotics or steroids or tea tree oil products may be prescribed
  • Products may be available in office to complement treatment, such as BIHOCL or eyelid scrubs