Chapter 15

Cataracts Patient Definition

A condition in which the lens of the eye gradually hardens and becomes opaque. Because light will no longer pass through the lens, the patient is gradually blinded.

Glaucoma Patient Definition

A condition of fluid build-up within the eye which causes pressure on the retina. If untreated, it can cause blindness.

Aphakia Treatment

A very strong corrective lens must be worn to replace the refractive power of the lens of the eye. This lens can be implanted in the eye, or worn as glasses or contacts.

Accommodation Technical Definition

Accommodation is the process by which the eye adapts itself to focus for the distance the object is from the eye. Three parts of the eye control this process: the lens, the cillilary body, and the suspensory ligament. In the normal eye, the lens is elastic and changes shape and therefore power, according to the distance the object is from the eye. The muscles that control the lens shape are located in the cillilary body. These muscles apply varying amounts of tension on the suspensory ligament to adjust the power of the lens.

Amblyopia Technical Definition

Amblyopia is a condition in which the muscles in one eye work harder than the other.

Aphakia Patient Definition

Aphakia is the post operative condition of the eye after the lens has been removed because of cataracts.

Amblyopia Treatment

As long as amblyopia is detected early, there is no problem in treating it. The use of the dominant eye is restricted to force the lazy eye to work, and strengthen the muscles. This is done with adjusted prescription in eye glasses, patching, vision therapy. If amblyopia is not treated early, the lazy eye can permanently atrophy. In extreme cases, the optic nerve may cease to function.

Presbyopia Technical Definition

As the person ages, the cells of the lens die, but are unable to be discarded. As a result, they are pressed to the center of the lens and form a crystalline substance that reduces the flexibility of the lens. This causes the eye to lose it's ability to accommodate.

Astigmatism Technical Definition

Astigmatism is caused by the cornea being elongated in shape. When light passes through the cornea it is hitting the retina at two points rather than one.

Astigmatism Treatment

Astigmatism is corrected with a cylindrical lens that has two powers which focuses the light rays at a single point on the retina.

Diplopia Patient Definition

Double Vision. A muscle imbalance confuses the brain into seeing two images.

Hyperopia Technical Definition

Farsightedness- is a refractive error in the lens of the eye which causes the light rays to converge behind the retina when sighting near objects. As a result, the patient has normal visual acuity for distant objects, but low visual acuity for near objects.

Hyperopia Patient Definition

Farsightedness. Hyperopia is a condition which the patient can see things far away clear, and things up close are blurry.

Glaucoma Technical Definition

Glaucoma is the condition of increased pressure in the globe. This occurs because the canal of schlemm becomes blocked, causing a build upon aqueous humor in the anterior chamber of the eye. As a result, pressure restricting the blood-flow to the retina. Decreased vision and permanent blindness may result.

Glaucoma Treatment

Glaucoma patients are immediately referred to an ophthalmologist for treatment, typically in the form of medications, and non-surgical procedures.

Hyperopia Treatment

Hyperopia is corrected by using a convex lens to bring the light rays together so that the image point falls directly on, rather than behind the retina.

Diplopia Technical Definition

In normal vision, the muscles of the eyes are in balance. Although each eye produces it's own image, these two images fall on corresponding areas of the retina. The brain brings these images together to form one image through a process called fusion. When the muscles of the eye are not in balance, the images fall on non-corresponding areas of the retina and the brain is unable to fuse them into one. As a result the brain sees two images.

Diplopia Treatment

In treatment of diplopia, you would put prism into the patients prescription eye glasses, to help the images fall on the same area of the retina, allowing the brain to see only one image.

Amblyopia Patient Definition

Lazy eye. A condition in which one eye works harder than the other. Although the lazy eye is healthy, it slowly weakens from lack of use.

Myopia Treatment

Myopia is corrected by using a concave lens to spread the light rays so that the image point falls directly on, rather than in front of the retina.

Myopia Technical Definition

Nearsightedness- is a refractive error in the lens of the eye which causes the light rays to converge in front of the retina when sighting distant objects. As a result, the patient has normal visual acuity for near objects, but low visual acuity for distance objects.

Myopia Patient Definition

Nearsightedness. Myopia is a condition in which the patient is able to see close up clear, but things at a distance are blurry.

Presbyopia Patient Definition

Presbyopia is the inability for the eye to focus on objects at varying distances due to the hardening of the natural lens in the eye.

Presbyopia Treatment

Presbyopia is treated with a multifocal lens to give the eye the ability to accommodate. This lens does the work the muscles in the eye are no longer able to do.

Cataracts Technical Definition

The lens may turn crystalline due to old age, accident, or a congenital condition. The blindness may not be complete because some light may pass through the lens. However, the condition usually continues to deteriorate with time.

Cataracts Treatment

The only treatment for cataracts is to surgically remove the lens of the eye. Following the removal of the lens, a very strong corrective lens is worn, or an artificial lens is implanted, to restore the ability of the eye to focus.

Accommodation Patient Definition

The process the eye uses to change focus for objects at varying distances from the eye.

Accommodation Treatment

There is no treatment for accommodation.

Astigmatism Patient Definition

When a person has an astigmatism the surface of the eye is shaped Iike a football, and it causes the light to focus at two points on your retina rather than one point.

Aphakia Technical Definition

When the natural lens of the eye is removed, only the inner cellular structure is removed. The outer membrane remains in place to hold the vitreous humor. The corrective lens required for an aphakic eye is on the order of 12D to 15D.