Refractive Eye Problems

The Human Eye and How It Works 

To understand how cataracts cause blurry vision, you'll probably find it helpful to know something about the structure of the eye and how it works. The eye is a complex organ that performs many complicated functions in a very ,short time - in the blink of an eye, you might say.

Refractive Eye Problems

Anatomy of the Eye 

If you could examine an entire human eye, you'd see a sphere about an inch in diameter - the size of a large gumball. The eyeball itself is really three thin layers surrounding a fluid-filled center. 

Sclera
 
The outside layer is the "white of the eye," called the sclera. It is the tough, opaque tissue that serves as the eye's protective outer coat. Six tiny muscles connect to it around the eye and control the eye's movements. The optic nerve is attached to the sclera at the very back of the eye.
 
Cornea 

Curving out from the sclera, the clear cornea is the "front window" of the eye. The cornea is amazingly strong and protective against dust and germs. Packed with nerve fibers, it is also quite sensitive to pain. This pain sensitivity is one of the cornea's protective qualities; the pain is a signal that something is trying to invade the eye.

Iris 

Under the sclera is another thin layer, which consists of the iris - the eye's visible colored ring; when we say that someone's eyes are blue, brown, or green, we are talking about the color of the iris. Besides being an interesting and expressive feature of the face, the iris is essential to clear vision. It surrounds the round, black pupil - along with muscle fibers and blood vessels.
 
Lens
 
The muscle fibers hold the lens of the eye in place and allow it to change its shape so that it can focus on objects at different distances. Located behind the iris and the pupil, the lens is about two-thirds water and one-third protein fibers. There are three distinct layers in the lens, sometimes compared to the layers of a peach:

• The capsule (the peach "skin") is a thin, clear membrane that forms the outside layer of the lens.
• The cortex (comparable to the peach "flesh") is the soft, clear material just beneath the capsule.
• The nucleus (the "pit" of the peach) is the firm center, or core, of the lens. 

Retina
 
The blood vessels, located toward the back of the eye, feed essential nutrients to the retina, a smooth, thin layer of nerve tissue at the back of the eye. When you are looking at an object, the retina is where the image comes into focus. Most of the retina contains specialized cells that convert the reflected light (the image) to signals your brain can interpret.
 
The macula is the focal point at the center of the retina. Within the macula are millions of light-sensitive nerve endings that act as photoreceptors. The photoreceptors called rods are sensitive to brightness and allow us to see in dim light. The photoreceptors called cones respond to the varying wavelengths of light that produce different colors.
 
The fovea centralis, in the center of the macula, is densely packed with cone cells. It is the fovea that gives your eye the ability to sharpen an image. The clearest vision - what we call "20/20 vision" - would be impossible without the fovea.
 
Another part of the retina, the retinal pigment epithelium, consists of dark tissue cells that absorb excess light and carry nutrients to, and waste products from, the retina.
 
Features that Protect the Eyes
 
The eyeballs are protected, in part, by their location - they are embedded in sockets, which are strongholds of bone, fat, and muscle. Other protective features of the eye are:

• Eyelashes, which protect your eyes from dust, contaminants, and other small particles
• Eyebrows, which trap liquids (such as perspiration) and particles that might otherwise find their way into your eyes
• Tears, which supply moisture that not only keeps your eyes from drying out but also contain substances that fight bacteria. If a foreign object gets into your eye, tear production increases to flush it out. When perspiration drips into your eyes, the high salt content makes your eyes sting, and the stinging stimulates tear production. The tears dilute the salty perspiration (or other liquid that might accidentally enter your eye) and cleanse the eye.
• Eyelids, which work like windshield wipers when you blink, to spread tears across the cornea. Blinking is usually automatic - you seldom have to remember to blink - but it is also a protective reflex that goes into action when your eyes perceive an object moving toward them or are assaulted by extremely bright light. 

To find out more, you can check out Refractive Eye Problems.

How To Strengthen Eyesight Naturally

Ghost Images and Double Vision
 
The tendency of cataracts to scatter light entering the lens can also cause double vision, especially if you're looking at a light source. Ghost images are similar to "seeing double." With double vision, however, you'll see two relatively clear images, whereas ghost images are fainter "copies" that appear on one side of or around the object you're looking at.

How To Strengthen Eyesight Naturally

Just as we are either right-handed or left-handed, we also have a dominant eye. Ghost images and double vision usually affect the dominant eye more than the weaker one.

Difficulty Seeing in Bright Light
 
In bright light the pupil becomes smaller, narrowing the pathway through which light enters the eye. A nuclear cataract located in that pathway is more likely to obstruct your vision when your pupils are constricted and the pathway is narrow.
 
Change in Color Vision
 
Age-related cataracts become grayish or yellowish as they thicken. Naturally, these tints affect your ability to distinguish colors. It's common for people with cataracts to report that colors look washed-out, faded, or yellowish.
 
Dealing with Early Cataract Symptoms 

In cataracts' early stages, getting stronger glasses or contacts and using a magnifying glass, a page magnifier, or better lighting can help you see more clearly. The American Foundation for the Blind recommends the following light sources for people with cataracts:

• Sunlight - but use proper eye protection if outside, and use window treatments if inside. Wear a hat with a visor or ultraviolet-filtering sunglasses outdoors. Indoors, reduce glare by sitting with your back to the window and by using window tinting, lattices, adjustable blinds, or sheer curtains.
• Full-spectrum or warm fluorescent bulbs can produce strong light and have several advantages over incandescent lights: They don't burn as hot, they don't create shadows, they last longer, and they use less energy. Many stores that sell fluorescent bulbs take back the burned-out ones for proper disposal. Call your local recycling center for information on how to dispose of regular and compact fluorescent bulbs.
• Incandescent bulbs have few advantages, now that miniature fluorescents are available for lamps. Incandescents do emit steady, constant light, whereas fluorescent bulbs may flicker, especially when they are about to bum out, and the flickering might be bothersome for some people with cataracts. If you're buying incandescent bulbs, look for those labeled "full-spectrum," which simulate natural sunlight. 
• Halogen bulbs are more energy efficient than incandescents, but they burn hotter. There is some evidence that the amount of blue light that halogen bulbs produce can be harmful to the eyes, and they pose slightly more fire danger than other bulbs. 

Experiment with a mix of different types of bulbs to see what works best for you. Though cataracts are considered a normal consequence of aging, certain lifestyle, environmental, and health factors can cause cataracts to develop earlier - and in different parts of the lens - for some people than for others. 

Causes and Risk Factors 

Although it's true that aging is the number one risk factor for cataracts, we don't all age at the same rate. If you've taken good care of yourself, your chronological age, in years, might be somewhat higher than your biological age - measured by the condition of your muscles, brain, lungs, and sensory organs. So what we call aging is, in part, the cumulative effect of damage to the body caused by sun exposure, disease, environment, and a number of other factors.

A lifetime of good health habits probably won't prevent cataracts altogether. If you've been kind to your body, however, it's quite possible that cataracts will develop later and will be less extensive - confined to the nucleus, perhaps, rather than developing in the cortex or the subcapsular area, or both. On the other hand, people with high blood pressure or obesity tend to develop posterior subcapsular cataracts, and taking a thyroid hormone may contribute to cortical-cataract development. To find out more, you can check out How To Strengthen Eyesight Naturally.