Disease of Eyes : Hypermetropia-Long Sightness

Hyperopia or hypermetropia, (hyper = over + metro = measure + op = sight, look + suffix ia = condition, state , thus a condition of over-measured sight) commonly known as being farsighted (American English) or longsighted (British English), is a defect of vision caused by an imperfection in the eye (often when the eyeball is too short or the lens cannot become round enough), causing difficulty focusing on near objects, and in extreme cases causing a sufferer to be unable to focus on objects at any distance. As an object moves toward the eye, the eye must increase its optical power to keep the image in focus on the retina. If the power of the cornea and lens is insufficient, as in hyperopia, the image will appear blurred.

The causes of hyperopia are typically genetic and involve an eye that is too short or a cornea that is too flat, so that images focus at a point behind the retina.

Disease of Eyes : Glaucoma

Glaucoma is a term for a group of eye disorders which result in damage to the optic nerve. This is most often due to increased pressure in the eye

Is glaucoma painful?

When the drainage angle of the eye suddenly becomes completely blocked, pressure builds up rapidly, and this is called acute angle-closure glaucoma. The symptoms include severe eye pain, blurred vision, headache, rainbow haloes around lights, nausea and vomiting.What is glaucoma and how does it occur?
If you have glaucoma, the aqueous humor does not flow out of the eye properly. Fluid pressure in the eye builds up and, over time, causes damage to the optic nerve fibers. Glaucoma can cause blindness if it is left untreated.

What are the main causes of glaucoma?

The increased pressure, called intraocular pressure, can damage the optic nerve, which transmits images to the brain. If damage to the optic nerve from high eye pressure continues, glaucoma will cause permanent loss of vision. Without treatment, glaucoma can cause total permanent blindness within a few years.

Disease of Eyes - Double vision, or Diplopia,

Double vision, or diplopia, is a symptom to take seriously. Some causes of diplopia are relatively minor, but others need urgent medical attention

What Causes Double Vision?

Opening your eyes and seeing a single, clear image is something you probably take for granted. But that seemingly automatic process depends on the orchestration of multiple areas of the vision system. They all need to work together seamlessly:

The cornea is the clear window into the eye. It does most of the focusing of incoming light.
The lens is behind the pupil. It also helps focus light onto the retina.
Muscles of the eye -- extraocular muscles -- rotate the eye.
Nerves carry visual information from the eyes to the brain.
The brain is where several areas process visual information from the eyes.
Problems with any part of the vision system can lead to double vision.

What Are the Symptoms of Double Vision?
Double vision can occur by itself with no other symptoms. Depending on the cause, other symptoms may be present with double vision, such as:

Misalignment of one or both eyes (a "wandering eye" or "cross-eyed" appearance)
Pain with eye movements in one or both eyes
Pain around the eyes, such as in the temples or eyebrows
Headache
Nausea
Weakness in the eyes or anywhere else
Droopy eyelids

Disease of Eyes : Hemeralopia - Night Blindness

Hemeralopia - Night Blindness

Hemeralopia  is the inability to see clearly in bright light and is the exact opposite of (night blindness). It can be described as insufficient adaptation to bright light. It is also called heliophobia and day blindness.

Night blindness (nyctalopia) is the inability to see well at night or in poor light. It is not a disease in itself, but rather a symptom of an underlying problem, usually a retina problem.

Disease of Eye - Colour Blindness

Color blindness, or color vision deficiency, is the inability or decreased ability to see color, or perceive color differences, under normal lighting conditions. Color blindness affects a significant percentage of the population. There is no actual blindness but there is a deficiency of color vision.

What is color blind?

People with deuteranomaly and protanomaly are collectively known as red-green colour blind and they generally have difficulty distinguishing between reds, greens, browns and oranges. They also commonly confuse different types of blue and purple hues.

Can humans be color blind?
Contrary to popular belief, it is rare for a color blind person to see only in shades of gray. Most people who are considered "color blind" can see colors, but certain colors appear washed out and are easily confused with other colors, depending on the type of color vision deficiency they have.

What do you see if you are color blind?
A person with color-blindness has trouble seeing red, green, blue, or mixtures of these colors. The most common type is red-green color-blindness, where red and green are seen as the same color.

What color is red to someone who is color blind?
The most common form of colour blindness is known as red/green colour blindness and most colour blind people suffer from this. Although known as red/green colour blindness this does not mean sufferers mix up red and green, it means they mix up all colours which have some red or green as part of the whole colour.

Disease of Eye - Cataracts

A cataract is a clouding of the lens in the eye leading to a decrease in vision. It can affect one or both eyes. Often it develops slowly. Symptoms may include faded colors, blurry vision, halos around light, trouble with bright lights, and trouble seeing at night.

What causes cataracts in people?

A cataract is a clouding of the eye's natural lens, which lies behind the iris and the pupil. Cataracts are the most common cause of vision loss in people over age 40 and is the principal cause of blindness in the world.

Is cataract a disease?

A cataract is an eye disease in which the clear lens of the eye becomes cloudy or opaque, causing a decrease in vision.How do you get a cataract?
Cataracts occur when there is a buildup of protein in the lens that makes it cloudy. This prevents light from passing clearly through the lens, causing some loss of vision. Since new lens cells form on the outside of the lens, all the older cells are compacted into the center of the lens resulting in the cataract.

How do you treat cataracts?

The only way of treating cataracts is with an operation. This is a very common operation. Around 300,000 cataract operations are performed each year in the UK. The operation involves removing the cloudy lens and replacing it with an artificial plastic lens (an intraocular implant).