Computer Vision

Computer Vision Syndrome (Digital Eye Strain)

DRY EYE DISEASE (DED) is the commonest eye OPD condition seen nowadays.

Causes of DRY eyes

As per various studies DED incidence is variously estimated to be 7% to even 33% in the general population.

The balance of tear production and tear loss through drainage and evaporation maintains the moisture level in the eyes. When this balance is not sustained, dry spots appear on the surface of the eye and cause irritation.

This number will continue to grow with our increasing screen time and reliance on smartphones, tablets, TV and laptops causing what is now known as Digital Eye Strain or Computer Vision Syndrome. With increasing use of screens by children for studies, social media and entertainment; this problem is increasingly being seen in much younger age also.
Modern lifestyle, Air Conditioning A.C., Heaters all increase dry eye problems.
Aging population is another factor, usually commoner in women than men.
Decreased sensitivity of the cornea can also lead to insufficient production of tears. Some types of contact lens wear can bring on this lack of sensitivity.

WHAT ARE THE SYMPTOMS OF DRY EYE?

One of the most common symptom of Dry Eyes is watery eyes as our lacrimal glands produce an excess of tears in an attempt to compensate for dry eyes, but this is counter productive as this watery fluid washes away the natural lipids & mucin which are important for eye surface health.

Early symptoms of dry eye are:

A burning sensation / heaviness in the eyes when in areas of low humidity or high pollution.
A gritty / sand particle like sensation in the eyes, which is persistent and painful.
Decreased tolerance of contact lenses.
In extreme cases of dry eye, patients may become unusually sensitive to light, experience severe eye pain, or notice diminished vision.
Stringy mucus in or around the eyes
Eye irritation from fan, A.C., blowers, smoke or wind.
Excess tearing or watering from eyes as a reaction to the dryness induced irritation in eyes.
Halos, Light Sensitivity, blurred focus of eyes.
Unable to keep eyes open, eyes feeling tired at the end of the day.
Dry eye syndrome results in discomfort, impaired vision with a decreased ability to perform activities that require visual attention, such as reading, computer work and driving a car.
Patients with the most severe disease are at increased risk of developing corneal infection, scarring or ulceration. These conditions can cause permanent vision loss
Certain eye drops which cause stinging, irritation work by increasing reflex watering and temporary relief by flushing out the debris and inflammatory bio-chemicals accumulated due to poor tear quantity & quality. However this is counter productive in the long run as explained above and such drops are not advised.

WHAT IS THE TEAR FILM?

Tears cover, protect and lubricate the eyes. With each blink, a new tear film layer spreads over the front surface of your eye.

The tear film is composed of three layers.

The outer oily layer of the tear film is produced by the meibomian glands in the eyelids and reduces evaporation of the tears. The thick middle watery layer is produced by the lacrimal gland beneath the upper eyelid and washes away irritants. The inner mucus layer is secreted by the goblet cells in the conjunctiva (mucous lining) of the eye and helps the tear film to adhere to the cornea.

There are three main components of tears and consequently three types Dry Eyes due to Lipid Layer, Aqueous Layer or Mucin Layer deficiency.

Underproduction– where there is poor production of fluid by the lacrimal glands The normal aging of tear glands, as well as specific diseases and disorders, may cause changes in the amount and condition of tears produced. Decreased sensitivity of the cornea can also lead to insufficient production of tears. Some types of contact lens wear can bring on this lack of sensitivity
Evaporative– tears evaporate too quickly. Result of poor oil production by eyelid meibomian glands. caused by meibomitis, which results from infection and inflammation of the meibomian glands in the eyelids. People with unusually large eyes, as well as those who suffer from thyroid disease, may also experience dry eye syndrome caused by excessive evaporation.

Evaporative Dry eye is due to excessive water loss from the exposed ocular surface in the presence of normal lacrimal secretory function. In Majority of cases it is due to insufficient lupid or oily layers of tears.
Inflammatory-Dry eyes may result in conjunction with inflammatory conditions.

HOW IS DRY EYE DIAGNOSED?

We diagnose dry eye by examining the eyes. Sometimes tests that measure tear production may be necessary. One test, called the Schirmer tear test, involves placing filter-paper strips under the lower eyelids to measure the rate of tear production under various conditions. Another uses a diagnostic dye (fluorescein or Rose Bengal) to look for certain staining patterns.

Grover Eye Laser Hospital offers a full comprehensive dry eye Management

Tests for Dry Eye

Objective tests:

Tear Break Up Time (TBUT)- The speed at which tear film breaks up reflects tear film stability. Automated non contact test is called NIBUT.
Schirmer’s Test– A test to measure tear production where strips of sterile blotting paper are placed under the lower lid at the outer corner of the eye for 5 mins. The length of wetting reflects the level of tear production.
Tear Osmolarity- This can be used to assess the severity of dry eye. The higher figure indicates high osmolarity and indicative of dry eye. A reduction in osmolarity is an excellent method of assessing the benefits of treatment.
Automated tests like Tear Film Interferometry, NIBUT, Meibography, Tear Miniscus & Blink analysis tests are also done if needed.
Lipiview / IDRA test: This is a sophisticated test that measures the tear thickness and in turn provides information about the lipid or oily layer on the surface of the eye. This can reflect the severity of meibomian gland dysfunction and along with Meibography it gives good diagnosis of cause of Dry Eyes.

TREATMENT OF DRY EYES

Depending on the cause, Dry Eye Syndrome can be treated as a temporary problem or a lifelong disease requiring long-term treatment. Either way, tears must be conserved or replaced in order to provide relief.

1. Adding Artificial Tears ( Lubricant Drops )
Artificial tears are probably the most common forms of treatment for Dry Eye Syndrome. These eye drops are similar to your own tears. They lubricate the eyes and help maintain moisture. Preservative-free eye drops are available if you are sensitive to the preservatives in artificial tears. Some people with dry eye complain of "scratchy eyes" when they wake up. Using a lubricant or artificial tear ointment at bedtime can help this symptom.
2. Conserving the tears with Punctal Occlusion
Tears drain out of the eye through small channels into the nose. We may close these channels either temporarily or permanently with punctum plugs or cautry. The closure conserves your own tears and makes artificial tears last longer.
3. NEW TECHNOLOGIES FOR DRY EYES TREATMENT

E-Eye, IRPL

TIXEL

LIPIFLOW

General Precautions for COMPUTER VISION SYNDROME & DRY EYE

Strain / Irritation / Watering Eyes is caused by Dry Eye & Allergy. This problem is aggravated by following :

Dry eye caused by Wind, Dust, Smoke, Plant Pollen exposure which is to be avoided.
Do not wash eyes too frequently. Do cold compresses instead.
More Evaporation of tears due to Dry Air Exposure : (Heater / A.C. –both can affect): Use glases / Photochromic Goggles full-time.
Infrequent Blinking of Eyes: Reduce TV / Mobile / Computer Use.
Regular use of goggles / sun-glasses / glasses helps to avoid sun and air exposure.
Use Helmet Visor if Driving / riding two wheeler. Avoid Car A/C or heater air at face. Keep car windows closed. Keep eyes closed whenever possible.
A person with dry eye should avoid anything that may cause dryness, such as an overly warm room, hair dryers, wind or a direct fan / air conditioner draft. Smoking and kitchen fumes are especially bothersome.
Avoid medicines for High B.P. like Atenolol (AT), Clonidine, Metoprolol, Propranolol, Tenolol, Betaloc (Beta Blockers) – Consult physician for change.
Avoid Pain / Joint Pain medicines like: Ibuprofen/ Ketoprofen / Combiflam / Brufen / Indomethacin / Diclofenac / Voveran etc.
Anti-Depression medication, Rheumatoid, Arthritis, Thyroid disorders and some Acne medicines also increase dryness of eyes.
In ladies after a certain age with hormone changes of menopause dry eyes often occur, and at times HRT or hormone replacement treatment is needed.
Avoid Eye drops with strong preservatives, specially for long-term use.

COMPUTER VISION SYNDROME, DIGITAL EYE STRAIN AND DRY EYES

Computer vision syndrome or CVS is a general term used to describe a group of eye problems / symptoms that occur when one works for long uninterrupted hours (more than 3 hours) on digital devices / video display units (VDUs) like computer, tablet / i-pad / mobile phones, T.V. etc..

Common Symptoms

Eye Strain:- Tired Eyes, dryness, burning sensation.
Dry, Irritated and itchy Eye :- Blurred / Double Vision, Light Sensitivity.
Headache:- Neck ache and Backache.
Reactive, excessive watering of eyes.

Reasons of Computer Vision Syndrome (Digital Eye Strain)

Excessive brightness / poor contrast on computer screen.
Dark / inappropriate background or room lighting
Glare and Reflections from monitor.
Incorrect placement of monitor & keyboard.
Decreased blink rate.
Poor seating posture.
Uncorrected Refractive errors.

Prevention and Management

Symptoms of computer vision symptoms can be resolved with proper management of environment and vision care.

1. Correction of Refractive Error / Glasses
Get Your Refractive Error Corrected and use correct Glasses with Anti-Reflective Coating as recommended by your doctor.
2. Blinking
Blink rate decreases to about 5 times a minute from the normal of about 15 times a minute while using computer / TV due to continuous staring at the screen. It is important to blink frequently and to keep eyes closed for short frequent breaks to maintain tear stability.
3. 20-20-20 Rule
Take a short break every 20 minutes for 20 seconds and look at an object that is more than 20 feet away to relax your eyes.
4. Monitor
- Monitor should be placed at a distance of about 18 to 30 inches from the eyes.
- Centre of monitor should be 6-8 inches below eye level
- Monitor should be straight ahead and tilted back 15 degrees.
- Higher Contrast and lesser brightness is ideal.
- Use large font with black or dark letters against light or white background
5. FONT
- The font size on the computer screen should be big enough to read the text from a distance.
- A dark font colour on a lighter background should be used.
6. DOCUMENT HOLDER
A document if needed should be fixed in a document holder should be positioned at the same distance and height as of the monitor.
7. Keyboard
Keyboard and mouse should be low elbow level.
8. Room Lighting & AC / Heating
- Light shining directly into the monitor should be avoided.
- Lighting should be adequate so that the monitor does not act as the only light source.
- Use Anti-Glare Screens or anti reflective coating (ARC) on spectacle lenses.
- Avoid direct AC or Heater air flow directly towards face. Avoid low humidity in room or car.
9. EYE EXERCISE

Closing the eyes and slowly rolling the eye balls in clockwise and anti clockwise direction.
10.Ergonomics, Follow good reading habits
- Sit on proper chair with right posture, let the light come over your Left shoulder and Fall directly on the page.
- Always place a table lamp which provides focused light on left corner of table.
- When you are reading, hold your book at least 40 cm away. Don’t bend your back and neck when reading. Hold the book at a slight angle to get a better view.