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In our modern world, people spend hours on end staring at computer screens, smartphones, tablets, e-readers, and books that require their eyes to maintain close focus.

For most people (all except those who are nearsighted and aren’t wearing their glasses), their eyes’ natural focus point is far in the distance. In order to move that focus point from far to near there is an eye muscle that needs to contract to allow the lens of the eye to change its shape and bring up-close objects into focus. This process is called accommodation.

When we accommodate to view close objects, that eye muscle has to maintain a level of contraction to keep focused on the near object. And that muscle eventually gets tired if we continuously stare at the near object. When it does, it may start to relax a bit and that can cause vision to intermittently blur because the lens shape changes back to its distance focal point and the near object becomes less clear.

Continuing to push the eyes to focus on near objects once the focus starts to blur will began to produce a tired or strained feeling in addition to the blur. This happens very frequently to people who spend long hours reading or looking at their device screens.

An additional problem that occurs when we stare at objects is that our eyes’ natural blink rate declines. The average person blinks about 10 times per minute (it varies significantly by individual) but when we are staring at something our blink rate drops by about 60% (4 times per minute on average). This causes the cornea (the front surface of the eye) to dry out faster. The cornea needs to stay moist in order to see clearly, otherwise little dry spots start appearing in the tear film and the view gets foggy. Think about your view through a dirty car windshield and how much that view improves when you turn the washers on.

So what should you do if your job, hobby or passion requires you to stare at a close object all day?

Follow the 20-20-20 rule. Every 20 minutes, take 20 seconds and look 20 feet into the distance. This lets the eye muscle relax for 20 seconds, and that is generally enough for it to have enough energy to go back to staring up close for another 20 minutes with much less blurring and fatigue. It also will help if you blink slowly several times while you are doing this to help re-moisten the eye surface.

Don’t feel like you can give up those 20 seconds every 20 minutes? Well if you don’t, there is evidence that your overall productivity will decline as you start suffering from fatigue and blurring. So take the short break and the rest of your day will go much smoother.

Article contributed by Dr. Brian Wnorowski, M.D.

Age-related macular degeneration, often called ARMD or AMD, is the leading cause of vision loss among Americans 65 and older.

AMD causes damage to the macula, which is the central portion of the retina responsible for sharp central vision. AMD doesn't lead to complete blindness because peripheral vision is still intact, but the loss of central vision can interfere with simple everyday activities such as reading and driving, and it can be very debilitating.

Types of Macular Degeneration

There are two types of macular degeneration: Dry AMD and Wet AMD.

Dry (non-exudative) macular degeneration constitutes approximately 85-90% of all cases of AMD. Dry AMD results from thinning of the macula or the deposition of yellow pigment known as drusen in the macula. There may be gradual loss of central vision with dry AMD, but it is usually not as severe as wet AMD vision loss. However, dry AMD can slowly progress to late-stage geographic atrophy, which can cause severe vision loss.

Wet (exudative) macular degeneration makes up the remaining 10-15% of cases. Exudative or neovascular refers to the growth of new blood vessels in the macula, where they are not normally present. The wet form usually leads to more serious vision loss than the dry form.

AMD Risk factors

• Age is the biggest risk factor. Risk increases with age.
• Smoking. Research shows that smoking increases your risk.
• Family history. People with a family history of AMD are at higher risk.
• Race. AMD is more common in Caucasians than other races, but it exists in every ethnicity.
• Gender. AMD is more common in women than men.

Detection of AMD

There are several tests that are used to detect AMD.

A dilated eye exam can detect AMD. Once the eyes are dilated, the macula can be viewed by the ophthalmologist or optometrist. The presence of drusen and pigmentary changes can then be detected.

An Amsler Grid test uses pattern of straight lines that resemble a checkerboard. It can be used to monitor changes in vision. The onset of AMD can cause the lines on the grid to disappear or appear wavy and distorted.

Fluorescein Angiogram is a test performed in the office. A fluorescent dye is injected into the arm and then a series of pictures are taken as the dye passes through the circulatory system in the back of the eye.

Optical coherence tomography (OCT) is a test based on ultrasound. It is a painless study where high-resolution pictures are taken of the retina.