UNDERSTANDING YOUR EYE PRESCRIPTION

If you need eyeglasses, it is because you were diagnosed with a refractive error during your eye exam. This means your eyes have trouble focusing and images can appear blurry. Types of refractive errors include being near-sighted (myopia), far-sighted (presbyopia) or having an astigmatism (your cornea is an irregular shape).

Understanding Your Eyeglass PrescriptionUnderstanding What 20/20 Vision Means

The number is based on you standing a distance of 20 feet in front of a standard eye chart to test your visual acuity. If during an eye test you can read the big E at the top of the eye chart, but none of the letters below that, your vision is considered 20/200. That means you can read a letter at 20 feet that people with “normal” vision can read at 200 feet, meaning you have very poor distance visual acuity. If you can read the seventh line from the top of most charts, your vision is 20/20. Any line below that would be 20/15 or below and indicates that you have exceptional visual acuity. Each eye is tested separately.

Understanding Your Eyeglass Prescription

The prescription you receive may be a form with headings that are filled in, or it may just be written out. In any case, it is written in a specific order, with the results for each eye listed separately.

OD is an abbreviation for oculus dexter, meaning right eye, while OS is oculus sinister, meaning left eye. If both eyes are being referred to the abbreviation you will see is OU (oculus uterque) meaning both eyes.

The next term on your prescription is Sphere (SPH) and is are measured in diopters (D). This number tells you how strong your lenses need to be to correct your vision. If this number has a minus sign (–), you are nearsighted; if the number has a plus sign (+) or is not preceded by any sign, you are farsighted.

Next may be cylinder (CYL), an indicator of the lens power if you have an astigmatism. The number for the CYL has the same format as the SPH, a minus sign (for the correction of nearsighted astigmatism) or a plus sign (for the correction of farsighted astigmatism). If there is no number given you either have no astigmatism, or your astigmatism is so slight that it is not really necessary to correct it.

If you do have a CYL number you will also have an axis number, based on a protractor scale that tells you where on the eye the astigmatism is found. For example, 

SPH –2.50   CYL +5.00 Axis 40 means you have a nearsightedness of -2.50 diopters with an astigmatism of +5.00 along the 40 degree axis.

If you are getting bifocals or progressive lenses, there is another number called an “Add.” This number is the amount of additional correction your eyes need to focus at close distance and will always be a positive number, whether or not the + sign is there.

Needless to say, eyeglasses can be expensive, but understanding a prescription should help you understand why. The stronger the lens the more expensive it is and then with each adjustment, the cost also increases.  Also, don’t forget that anti-glare or UV protective coatings add to the costs, but most people feel it is well worth it. Eye glasses are an investment in your safety, job, independence and letting you enjoy leisure-time activities you enjoy.

How to Prevent Eye Strain While Working From Home

Working from home has become the new normal for many Americans during this pandemic.  Most are happy without the commute, although working outside the office and in all sorts of strange places, such as bedrooms, backyards, living rooms, has become common place. We’ve had to learn how to work remotely, which in turn means spending a lot more time using computers and smartphones.

Moving out of properly-lit classrooms and offices – and away from ergonomically correct desks – can have long-term effects on our eyes.  Excessive time at a computer screen under the best conditions can lead to symptoms of eye strain.

Eye Strain Symptoms include:

  • Headaches
  • Blurred vision
  • Uncomfortable dry eyes
  • Neck and shoulder pain

To help avoid eye strain, here are few tips for working from home:

  • Record time spent on screens – Most adults age 18 and older spend at least 13 hours each day using digital devices. Extended screen time can cause discomfort and vision difficulties. When working from home, you may lose track of how much time you’re on your computer or smartphone.  So keep track of the hours you use devices. That way, you’ll be aware of the demand you’re placing on your eyes.
  • Rest and blink your eyes – Researchers found that over 30% of people using digital devices rarely take time to rest their eyes. Just over 10% say they never take a break, even when working from home. The eye muscles get overworked and don’t get a chance to relax and recover. Experts suggest the 20-20-20 rule; every 20 minutes, focus your eyes and attention on something 20 feet away for 20 seconds.  You can also get up and walk around for a few minutes.

 

  • Reduce exposure to blue light – In the spectrum of light, blue is more high energy and close to ultraviolet light. So, if you use screens throughout the day, ask your eye doctor about the value of computer glasses that block blue light. Reducing exposure to blue light may help lessen vision problems.  At home, using digital devices until bedtime can overstimulate your brain and make it more difficult to fall asleep. Eye doctors recommend no screen time at least one to two hours before going to sleep.

  

  • Sit up straight – Proper posture is important. Your back should be straight and your feet on the floor while you work. Elevate your wrists slightly instead of resting them on the keyboard.

 

 

  • Proper lighting – A setting that’s too bright (sunny backyard) or too dim (cavernous basement) can cause eye strain and headaches. Your screen should be bright enough that you don’t need to squint. A screen shield can help reduce glare.

 

  • Set up monitor properly – Make sure your computer screen is about 25 inches, or an arm’s length, away from your face. The center of the screen should be about 10-15 degrees below eye level.  Cut glare by using a matte screen filter. You can find them for all types of computers, phones, and tablets.  Increase font size or set the magnification of the documents you are reading to a comfortable size.

 

  • Consider computer glasses –For the greatest comfort at your computer, you might benefit from having your eye doctor modify your eyeglasses prescription to create customized computer glasses. This is especially true if you normally wear distance contact lenses, which may also become dry and uncomfortable during extended screen time.  Computer glasses also are a good choice if you wear bifocals or progressive lenses, because these lenses generally are not optimal for the distance to your computer screen.
  • Create Technology-Free Zones – These tips can help reduce eye strain when you’re forced to look at screens all day, creating technology-free zones in certain areas of your home, like the bedroom or bathroom. If you spend the entire day working on the computer, getting in bed and scrolling through social media until you fall asleep won’t do your eyes any favors.

Once you’re done for the day, truly unplug. Read a book or spend some quality time with family members without your phone.

 

  • Get an Eye Exam – If you have tried all these tips and eye strain is still an issue, it might be time to see an eye care professional to schedule an eye exam.  The exam may even detect underlying issues before they becomes worse.

 

 

 

 

 

Blinking – Why is it so important?

Blinking is something we all do every minute, whether we think about it or not. The average person blinks 15-20 times per minute, or about 1,200 times per hour.

So why do we unconsciously move our eyelids over our eyeballs so many times? Because it’s extremely important for your eyes and vision.

Although you may not think of blinking as a major component of your health care routine, if you didn’t blink for extended periods you’d be at higher risk of eye infection.  You would also have uncomfortable, dry eyes and would have decreased clarity of vision. The most important benefit of blinking is that it cleans the surface of your eye of any debris and washes it away with fresh tears. The thin coating of tears helps sharpen your vision, clearing and brightening the image your retina receives. Blinking also nourishes your eye with oxygen and nutrients, keeping your eyes healthy and comfortable.

Blinking wipes and renews your tear film, the smooth, moist layer covering our eyeballs.

The tears have 3 important layers.  The inner most is the mucous layer that contains ‘mucins’ to keep the tears attached to the surface cells of the cornea.  This material is produced by ‘goblet cells’ in the conjunctiva.  The next layer is aqueous or ‘water-like’ that is produced by the lacrimal gland located in the upper-outer quadrant of the eye region. Finally, the outer layer is lipid or ‘oil-like’ that prevents the other layers from evaporating. These lipids are produced by tiny glands along the lid margins, next to the eyelashes.  If any of these layers are absent or abnormal, then the cornea becomes vulnerable to damage.

The tears contain many protein components such as lysozyme, which function like natural antibiotics. The tear film also contains many nutrients and amino acids to nourish the cells of the cornea, which is the clear, dome-like structure on the front of the eye.

Besides keeping your eyes lubricated, the tear film also:

  • Helps form an almost perfectly smooth front optical surface on the cornea helping light to focus properly.
  • Washes away debris.
  • Transfers oxygen from the atmosphere to the cornea, since the cornea lacks blood vessels to deliver it directly.
  • Provides a pathway for white blood cells when there is an injury to the eye’s surface.
  • Prevents infection due to presence of lysozyme and other antibacterial enzymes.

Your eyelids also play a significant role, aside from protecting your eye and keeping things dark while you sleep. There is also a slight horizontal movement of the eyelid that pushes debris toward the tear ducts, which are the small openings at the inner corners of the eyes through which tears drain into your nose. That is why your nose runs when you cry.

Blinking exercises are a great way to keep your eyes moist. Blinking stimulates tear production and gives our eyes a chance to wash away any debris that has accumulated on the surface of the eye. Individuals who spend a lot of time on the computer or reading a lot tend to blink less often than they should. Therefore, if your eyes feel dry and irritated when using the computer or reading, then look away and do the following blinking exercises.

Blinking Exercises for Dry and Irritated Eyes:

  1. Close your eyes quickly and tightly. Squeeze your facial muscles around your eyes for three to five seconds. Open your eyes slowly and relax your facial muscles. Keep your eyes open for another three to five seconds and repeat the squeezing process five to seven times.
  2. Use the 10-10 rule and every 10 minutes look at away from your computer and intentionally blink 10 times. Then resume your activities.