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Tag: vision

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. Elisa Xiao

How can I have Dry Eye if my eyes feel watery?

Photo by Pascal Chanel on Unsplash

Tearing

Tears are needed to keep the eye’s front surface healthy and to maintain clear vision. It is
common to temporarily produce excess tears when you are emotional, laughing, coughing,
vomiting, experiencing strong taste sensations, or yawning.

Types of Tears

photo credit: allaboutvision.com

Different types of tearing consist of basal tears, emotional tears, and reflex tears. Basal tears are your basic functional tears. They are released in tiny amounts to lubricate your ocular surface and keep it clear of any dust. These are vital for good vision and comfort. Emotional tears are triggered by strong feelings such as joy or sadness. Reflex tears result from irritation in the eye by foreign bodies, or from the presence of irritant substances in the environment. They can also occur with bright lights hot or peppery stimuli to the tongue and mouth, when we yawn, cough or even vomit. These types of tears are released in larger amounts than basal tears. Their goal is to protect one’s eye.

How can I have Dry Eyes if my eyes are so watery?

The two common causes of watery eyes are blocked tears ducts and excessive production of tears. The common cause of excessive production of tears is dry eye syndrome. This occurs due to the glands around our lid margins not producing enough oil resulting the tears drying up very quick. This lack of lubrication results in our eyes producing an abundance of tears to compensate.

Posted on by Dr. Melody Tong

Is it true that eating carrots can improve my vision?

Photo by Nick Fewings on Unsplash

It is often said that eating carrots will help you see better due to the high amounts of vitamin A. Although vitamin A plays an important role in our vision, it is unable to improve the quality of our vision. Vitamin A is able to prevent diseases such as macular degeneration which can result in severe vision loss if left untreated.

What is Vitamin A?

Vitamin A is derived from beta-carotene which acts as an antioxidant. This is essential in protecting our cells against heart disease, cancer, and many other diseases. Deficiency in vitamin A is the leading cause of preventable blindness in children across the world. Due to this, it is important to have some type of source for vitamin A such as carrots, eggs, spinach, or broccoli.

What does Vitamin A do for our eyes?

Vitamin A allows us to produce pigments needed in-order for the retina to function properly. Without these pigments, it would become much more difficult to see in the dark leading to eventual night blindness. Lack of vitamin A can also lead to a lack of nourishment to the cornea resulting in the eyes not producing enough moisture to keep the cornea lubricated. This can lead to our eyes becoming dry which can result in severe complications such as ulceration of the cornea and eventual blindness if not appropriately treated.

Posted on by Dr. Elisa Xiao

Will I Develop Presbyopia?

Photo by bruce mars on Unsplash

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. Melody Tong

Headache or Ocular Migraine?

Photo by New Africa/ Shutterstock

Migraines are often associated with pounding headaches, but they can also affect your vision. Ocular migraines, also known as retinal migraines or visual migraines, are a unique type of migraine that primarily manifests as visual disturbances. This means that the symptoms revolve around your eyes and the way you perceive the world around you. The visual disturbances associated with ocular migraines are short-lived, lasting less than an hour.  

Visual disturbances can include:

  • Flickering lights
  • Shimmering or zigzag lines
  • Temporary blind spots
  • Momentary loss of vision in one eye

Triggers can include:

  • Stress
  • Hormonal fluctuations
  • Specific foods
  • Exposure to bright lights, or even distinct patterns

Although ocular migraines are relatively benign, it’s essential to distinguish them from more serious conditions that can cause similar visual disruptions, such as retinal detachment.

Always seek prompt medical attention if you experience sudden visual changes.