A cataract is a clouding of the eye's naturally clear lens. The lens becomes like a window that is frosted or yellowed. Cataracts are a common cause of vision loss, especially as we age, but they are treatable.

No, but early detection and treatment can control glaucoma and reduce the chances of vision loss

The optic nerve, at the back of the eye, carries visual information to the brain. As the optic nerve fibers are damaged, the amount and quality of information sent to the brain decreases and a loss of vision occurs.

Floaters are cobwebs, strings, or speck-like objects that float in the field of vision. They may occur from any opacity within the vitreous gel that casts a shadow on the retina. They are usually black and may float in and out of view.

If diagnosed at an early stage, glaucoma can often be controlled with little or no further vision loss. If left untreated, first peripheral vision and then central vision will be affected, and blindness may result.

When the retina detaches, it separates or pulls away from its normal position lining the inner back wall of the eye. A retinal detachment can occur from retina holes, retinal tears or from traction on the retina from scar tissue on the retinal surface or in the vitreous gel. If not promptly treated, a retinal detachment can cause permanent loss of vision.

A comprehensive optometric examination will include tests for glaucoma. A simple, painless procedure called tonometry measures the internal pressure of your eye. Your optometrist will also check the health of the optic nerve and measure your field of vision.

• Blurring of central vision
• Blind spots in the central vision
• Difficulty seeing detail up close and at a distance
• Distortion of lines and shapes
• Diminished color vision

Most people with macular degeneration retain peripheral vision and learn to optimize the use of their remaining vision. Low vision aids can sometimes be helpful too.

Orbital tumors can occur in the bones, muscles, tissue, and blood vessels of the orbit area that houses the eyeball. Orbital tumors can also occur on or behind the eye.

Headaches are only rarely caused by eye problems, even if the pain feels like it is coming from or behind the eye. One explanation for this perhaps surprising statement is that the eye socket is often the site of "referred pain", that is, a sense of discomfort in one part of the body because of a problem that is truly elsewhere. This is similar to the occurrence of left arm pain in patients who experience a heart attack.

Eyelid retraction is usually treated with lubricating eye drops and ointment until surgery can be performed to bring the eyelids back to their normal resting place.

Visual loss occurs because of either optical or neural problems. Optical causes of visual loss [such as refractive error (need for glasses), cataract or corneal opacities] can usually be corrected or significantly improved. Nerve damage (for instance to the retina or optic nerve) cannot be repaired

Eyelid retraction is usually caused by past eye trauma, thyroid eye disease, or loss of tone due to aging.