Color blindness, in the formal medical term, color vision deficiency is any abnormality of the color vision system that causes a person to see colors differently than most people or to have difficulty distinguishing among certain colors.

 Color vision deficiency is detected by tests that use special color plates under daylight conditions. The test usually is conducted during the childhood years. It is also performed when an adult applies for a job in which color vision is essential, such as airline pilot. The exact degree of color vision deficiency can be determined by a test that requires the arrangement of sequences of colored chips or by an instrument called an anomaloscope, which shines a mixture of red and green lights. The person being tested adjusts the mixture until it appears the same as a fixed spot of yellow light. An adjustment that yields a mixture that is too red or too green indicates the presence and severity of color vision deficiency.

Many people with color vision deficiency are not aware of the problem because it does not interfere with everyday living. It can be detected during employment tests for an occupation requiring normal color vision. Such positions include airline pilot, commercial artist, marine pilot, color photographer, or electrician, where the ability to distinguish color-coded wires is important. There is no treatment for the condition.

A person with color blindness is unable to distinguish some or all of the colors visible to a person with normal color vision.

Color blindness falls into three sub-categories:

1. Monochromacy

 Monochromacy, also known as “total color blindness”, is the lack of ability to distinguish colors; caused by cone defect or absence. Monochromacy occurs when two or all three of the cone pigments are missing and color and lightness vision is reduced to one dimension.

2. Dichromacy

Dichromacy is a moderately severe color vision defect in which one of the three basic color mechanisms is absent or not functioning. It is hereditary and sex-linked, affecting predominantly males. Dichromacy occurs when one of the cone pigments is missing and color is reduced to two dimensions.

3. Trichromacy

Anomalous trichromacy is a common type of inherited color vision deficiency, occurring when one of the three cone pigments is altered in its spectral sensitivity. This results in an impairment, rather than loss, of trichromacy (normal three-dimensional color vision)

Eye surgery is also recognized as orogolomistician surgery or ocular surgery. It is a surgery performed on the eye or its adnexa by an ophthalmologist. Even though most eye surgery can be performed by an experienced general ophthalmologist.

There are four main types of eye conditions - myopia, hyperopia, Presbyopia and astigmatism.
Myopia – Also called as nearsightedness, is the problem of not being able to see what is far away without glasses.
Hyperopia – Also called as farsightedness, is the other way round or opposite of myopia.
Presbyopia – In this the eye exhibits an increasingly diminished capability to focus on near objects with age.
Astigmatism - It is little different, where the patients have irregularities in their cornea which as a result distorts the image formed on the retina of the eye.

After an Eye Surgery the need for glasses or contact lens will either be negated, or your dependency on them will be significantly reduced. But eye operation comes with its own set of risks and they should always be careful seriously before you actually sign-up for an operation.

You will not be suitable for the operation if you are suffering from diabetes, glaucoma, cataracts, arthritis, and lupus. Even pregnant women are not suitable. With these conditions, undergoing surgery can cause permanent damage to your vision. Other problems that might be caused due to surgery are double vision, glare, and halo. One’s nighttime vision can also be affected, particularly for certain operation procedures. Even permanent unclear vision and diminished contrast may be the effects of the surgery. Some patients experience discomfort in the first 24-48 hours after surgery. Other side effects, even if unusual, may include- Glare, Seeing halos around images, Difficulty driving at night, fluctuating vision.

Advantages of Lasik are -

1. Most of the surgeons worldwide consider refractive surgery to be the preferred choice.
2. Increases self-confidence
3. Clarity of vision within hours of surgery
4. Extremely predictable
5. No more daily cleaning rituals or recurring costs as with visual aids
6. Both eyes treated on the same day
7. Greater convenience for playing sports
8. Broad range of treatable prescriptions

Similar to our fingerprints, each of our eyes is dissimilar and has its own exceptional shape and visual individuality. Having poor eyesight is a barrier that creates unnecessary  challenges and sets pointless limits on what you can do in your every day life.
The three factors that create poor eyesight are:

1. The curvature of the cornea
2. The length of eyeball.
3. The light that enters your eyes cannot focus at the proper place.

  
There are three ways to help out persons who go through from unclear vision or poor eyesight

Spectacles -
For centuries, mankind has well-known how to use eyeglasses to transfer the rays of light to their proper points. It is a not dangerous and accepted technique of correcting ones vision, but there can be limits, such as when playing sports, occupational hazards or limits and even self-consciousness that the eyeglass wearer might feel.

Refractive Surgery -
Researchers have developed Radial Keratectomy and PRK (Photorefractive Keratectomy) and LASIK (Laser In-situ Keratomileusis). For LASIK, this is the great revolution in ophthalmology innovation.
 As all things have the side effects, restrictions and complications of Refractive surgery. A balanced opinion of the advantages of Refractive surgery with the identified and unidentified risks. It is significant to recognize that it is not possible to perform any form of surgery without the patient accepting a definite amount of risk and responsibility.

Contact Lenses -
When Contact lenses were developed, public were given an additional technique to improve their vision. One benefit that contact lenses recommend over eye glasses is a wider field of vision, but the daily, required rituals of cleaning the lenses, inserting them into the eyes and taking them out and re-cleaning them another time at night causes some people to shy away from converting to contacts. In addition, if the lens are not taken proper care of and cleaned regularly, there is a risk of infection. For some people with high astigmatism, contact lenses just do not work.

Refractive eye surgery is a type of eye surgery that is used to rectify refractive errors of the eye and decrease dependency on corrective lenses such as eyeglasses and contact lenses. Successful refractive procedures can reduce myopia or nearsightedness, hyperopia or farsightedness, and astigmatism or elongated corneas. A number of different procedures exist for refractive eye surgery depending upon the type and severity of the refractive error.

There are four main types of refractive eye surgery procedures: flap and photoablation procedures; corneal incision procedures; thermal procedures; and implants. Currently, the most common refractive eye surgeries involve the use of lasers to reshape the cornea. Flap procedures involve cutting a small flap in the cornea so that the tissue underneath can be reshaped to correct the refractive error.

LASIK, short for Laser Assisted In-Situ Keratomileusis, is the most popular refractive surgery and is used to correct myopia, hyperopia, and astigmatism. The LASIK procedure involves using a microkeratome or IntraLase to cut a flap into the stroma, moving the flap out of the way, removing excess corneal tissue with an excimer laser, then replacing and smoothing out the flap. LASEK is best suited for individuals with thin or flat corneas. The LASEK procedure uses a small trephine blade to cut into the shallow epithelium, after which the eye is bathed in a mild alcohol solution to soften the edges of the epithelium. The flap is gently moved out of the way so that an excimer laser can remove excess corneal tissue, after which the flap is replaced and smoothed out.

Epi-LASIK, like LASEK, involves a shallow cut into the epithelium, but makes use of epikeratome to create a thin epithelium sheet for removal instead of the harsher blade and alcohol. Photoablation, the second stage in flap procedures, makes use of ultraviolet radiation to remove excess corneal tissue. PRK, or photorefractive keratectomy, was the original laser eye surgery procedure. PRK involves numbing the eye with local anesthetic eye drops, and reshaping the cornea by destroying miniscule amounts of tissue from the surface of the eye. The laser used, an excimer laser, is a computer-controlled ultraviolet beam of light. It burns cool so as not to heat up and damage the surrounding eye tissue. Corneal incision procedures such as radial keratotomy and arcuate keratotomy use miniscule incisions in the cornea to alter its surface and correct refractive errors.

 Radial keratotomy, or RK, uses a diamond tipped knife to make a number of spoke-shaped incisions in the cornea. The result of the incisions is that the cornea flattens out, minimizing the effects of myopia. Arcuate keratotomy, or AK, is very similar to RK. The diamond knife is used to cut incisions that are parallel to the edge of the cornea, as opposed to the spoke-shaped incisions of the RK procedure. These procedures have been much less common with the emergence of laser-assisted refractive eye surgeries.

 Thermal procedures use heat to correct temporarily hyperopic refractive errors, or farsightedness. The thermal keratoplasty procedure involves putting a ring of 8 or 16 small burns on the eye immediately surrounding the pupil. The application of the heat increases the slope of the cornea, making it steeper, through thermal contractions. There are two main types of thermal keratoplasty. Laser Thermal Keratoplasty, or LTK, is a no-touch procedure that uses a holmium laser.

 Conductive Keratoplasty, or CK, uses a high-frequency electric probe. The final type of refractive eye surgery involves the use of implants. Implantable contact lenses, or ICL, can be used to correct severe levels of myopia, hyperopia, and astigmatism. The implants are actually tiny contact lenses that are inserted through a small incision in the side of the cornea. Implants are seated so they sit immediately in front of the eye’s natural lens just behind the cornea. ICL works in conjunction with the eye? natural lens to refocus light on the retina and produce a crystal clear image. Each of these procedures has its advantages and disadvantages, and not all individuals are suitable candidates for refractive eye surgery. Individuals who are interested in learning more about surgical options should contact their ophthalmologist for more information about these procedures, as well as inquire about other new cutting-edge procedures. Since ophthalmologic surgery is constantly growing and changing with emergence of new technologies and methods, there are always new techniques in development.