Color Contacts\ Color Contacts lenses| Benefits & Types of CC

Color Contacts - Brief Description

What are the Color Contacts? What are the Benefits of color contacts lenses? Types of Color contacts lenses?  This article will helps to answer your question on color contacts.

What are the Color Contacts: - Contacts that do not have a corrective or powered lens. They are only meant for fashionable purposes and mainly aim to change the physical appearance of a person. Non Prescription Colored Contacts are very affordable and therefore you can get or collect different colors to be able to combine or match it with your daily outfit. The Non Prescription Colored Contacts are available in many colors which will surely suit whatever your mood is.

For people with vision problems, contact lenses remain an effective, almost invisible tool. The thin plastic or glass lenses are fitted over the cornea of the eye to correct vision problems such as nearsightedness, farsightedness or astigmatism. These days you can wear contact lenses even if you have presbyopia and need bifocals. You can buy color contacts as frequent replacement lenses or even as disposable lenses.

There are four Major types of colored contact lenses, each offering a slightly different benefit:

• Visibility tint: -  These colored contact lenses are lightly tinted so you can find your lens if you drop it. Visibility tints don't affect the color of your eyes. A visibility tint allows you to see your lens better while inserting it or during removal. It is a very light tint, usually in light blue or green thus does not influence your eye color. The purpose of this visibility tint is to allow you to quickly find the lens in the lens case or if you dropped the lens on the counter of floor. Since visibility tinted lenses do not change eye color they are typically only worn by those with eye problems needing vision correction.
• Enhancement tint. These colored contact lenses have a translucent tint that's meant to enhance your natural eye color. Enhancement tints are slightly darker than a visibility tint. An enhancement tint is a solid tint that is darker than a visibility tint and does influence your eye color. Enhancement tints intensify your existing eye color, thus "enhancing" your already either green or blue eyes to perhaps a different shade. For example you might enhance your blue eyes to an aquamarine color using this type of lens. These tints do not work on dark irises.
• Color tint. Darker, opaque tints that change the color of your eyes. Color tints come in a wide array of specialty colors, including amethyst, violet and green. The center of this colored contact lens is clear so you can see. Color tints offer the most dramatic color change for eyes. If you want to completely change the color of your eyes, from blue for example to green, you can use a color tint to achieve the desired outcome. A color tint lens is necessary for people with dark eyes to change their eye color.
• Light-Filtering tint. These colored contact lenses are designed for athletes and sports fans. They enhance certain colors and mute others to make balls stand out. For instance contact lenses for tennis players would enhance optic yellow, the color of tennis balls. This is a newer type of color tint that many are using for sports. Light-filtering tints help enhance some colors while muting others. Let's say for example you are a soccer player. A light-filtering tint can enhance the color of the ball you are using so it is easier to find and take advantage of while playing. This type of tint is increasingly popular among golfers, allowing them to tell the difference between various shades of green while on the golf course.

Other Types of Color Contact Lenses

Each type of colored contact lens will create different eye color effects. Let's look at a few of the types of available:

• Opaque - Color tints offer the most dramatic color change for eyes. If you want to completely change the color of your eyes, (for example brown to blue), choose an opaque lens. A color tint lens is necessary for people with dark eyes to change their eye color.

• Costume - Costume color lenses are for those that want to dramatically change the color and shape of their eye either to enhance a costume or for theatrical performances. The color is painted on to the contact lens to add special effects to your eyes. If you want to go for a cat eye appearance, then costume lenses will provide you just the look you need!

• Non Prescription Colored Contacts: -  do not need prescription from a doctor therefore anyone can surely get unlimited numbers of Non Prescription Colored Contacts. Non Prescription Colored Contacts can last for about three months and therefore you do not need to change your contacts every month thus you can save money.

Will You Need A Prescription To Take Advantage of Colored Lenses?

Even if you don't need a vision correction prescription, you will need a prescription for colored contact lenses. Getting a prescription will ensure a good fit for your lenses and will help you to avoid many problems associated with wearing contacts.

Know that you should never buy colored contact lenses from a supplier who doesn't require a proper fitting or prescription. Chances are they are being sold illegally. Fortunately, it doesn't take long for an optometrist to fit you for contact lenses.

Contact Lenses -1.75 | What does it stand for

Contact Lenses -1.75 - What Does It Stand For

Contact Lenses -1.75 >> It is the power of the contact lenses you are going to buy for your eyes. This is done by the Contact lenses Prescription. It is done by the EYE Doctor. There are Few Tests, measurements & Calculation while contact lenses Prescription test takes place. It is measured to get the right selection of the contact lenses with right power which one's eyes need for correcting the visionary effects.

First of all, just take a look at the simple chart below. Since we already know that lens power of 4.00 D or greater requires vertexing at each meridian, so we start with 4.00 D = add vertex factor of +0.25 D. For every 2 D power change, you will require a vertex factor change of +0.25 D.
Power of lens Vertex Factor (VF)
4.00 D +0.25 D
6.00 D +0.50 D
8.00 D +0.75 D
10.00 D +1.00 D
12.00 D +1.25 D
14.00 D +1.50 D
16.00 D +1.75 D
Example #1:
OD: -10.00 – 5.00 x 180
OS: +5.00 – 1.00 x 180
Given: Spectacle Rx for OD: -10.00 – 5.00 x 180. What’s the contact lens Rx?
1) Sphere power = -10.00 D –> -10.00 + vertex factor of +1.00 D = -9.00 D at 180th meridian
2) Sphere + Cylinder power = -10.00 – 5.00 = -15.00 D –> -15.00 + VF of +1.50 = -13.50 D at 90th meridian
3) Adjusted Cylinder power = -5.00 D + VF of +1.50 = -3.50 D
4) Estimated Rx = -9.00 – 3.50 x 180 (Need to ADD -0.25 to cylinder power to obtain the Final Rx)
5) Final Rx = -9.00 – 3.75 x 180

Given: Spectacle Rx for OS: +5.00 – 1.00 x 180. What’s the contact lens Rx?
1) Sphere power = +5.00 D –> +5.00 + vertex factor of +0.25 D = +5.25 D at 180th meridian
2) Sphere + Cylinder power = +5.00 – 1.00 = +4.00 D –> +4.00 + VF of +0.25 = +4.25 D at 90th meridian
3) Adjusted Cylinder power = -1.00 D + VF of +0.25 = -0.75 D
4) Estimated Rx = +5.25 – 0.75 x 180 (Need to ADD -0.25 to cylinder power to obtain the Final Rx)
5) Final Rx = +5.25 – 1.00 x 180

Useful Notes:
a) Spectacle plane –> Contact lens plane
(Remember: “CAP” = Closer ADD Plus!!!)
b) Minus spectacle Rx –> contact lens Rx (CLRx) = expect contact lens Rx to be LESS minus.
Ex: SRx = -4.50 D –> CL Rx = -4.25 D
c) Plus spectacle Rx –> contact lens Rx = expect contact lens Rx to be MORE plus.
Ex: SRx = +5.00 D –> CLRx = +5.25 D
- See more at: http://www.optometrystudents.com/pearl/how-to-rapidly-determine-a-contact-lens-prescription/#sthash.vWKP6NKA.dpuf

The formula for a contact lens prescription describes the amount of refractive error from normal vision. This article will show you how to read a contact lens prescription.

O.D. : -  This stands for Oculus Dexter, a Latin term for right eye. All of the numbers next to this row or column indicate the strength of correction needed for your right eye.

O.S. : - This stands for Oculus Sinister, a Latin term for left eye. All of the numbers following this row or column indicate the strength of correction needed for your left eye.

Power (PWR) or Sphere. They are usually the first set of numbers listed in the OD and OS rows/columns. It is common for the correction to differ between the right and left eyes. If you find the term PL, this stands for Plano, and it means the number is 0 and no correction is needed .

A negative number in this field indicates myopia, otherwise known as nearsightedness or the ability to see things clearly when they are close to you, but not when they are far away. For example, if the field under OD reads -1.75 D, this indicates the person has  diopters of nearsightedness in the right eye.

A positive number in this field indicates hyperopia, otherwise known as farsightedness, or the ability to see well in the distance, but not nearby. For example, if the field under OD reads +1.75, this indicates the person has 1.75 diopters of farsightedness in the right eye.

CYL and AXIS. These numbers indicate astigmatism, a common condition. It is usually caused by an irregularly shaped cornea, but can also be caused by an irregularly shaped lens inside the eye.

CLY stands for cylinder and it is the measure of astigmatism in diopters. Most doctors use a positive number, but if a negative number is given, a lens store may need to convert to a positive number.

AXIS is the degree measurement that is required to bend light to correct the irregular shape of the cornea.

All of the above calculation are taken place before prescribing for contact lenses for particular eyes. There are some other factors which also necessary for the right prescription of the contact lenses. 

First of all, just take a look at the simple chart below. Since we already know that lens power of 4.00 D or greater requires vertexing at each meridian, so we start with 4.00 D = add vertex factor of +0.25 D. For every 2 D power change, you will require a vertex factor change of +0.25 D.
Power of lens Vertex Factor (VF)
4.00 D +0.25 D
6.00 D +0.50 D
8.00 D +0.75 D
10.00 D +1.00 D
12.00 D +1.25 D
14.00 D +1.50 D
16.00 D +1.75 D
Example #1:
OD: -10.00 – 5.00 x 180
OS: +5.00 – 1.00 x 180
Given: Spectacle Rx for OD: -10.00 – 5.00 x 180. What’s the contact lens Rx?
1) Sphere power = -10.00 D –> -10.00 + vertex factor of +1.00 D = -9.00 D at 180th meridian
2) Sphere + Cylinder power = -10.00 – 5.00 = -15.00 D –> -15.00 + VF of +1.50 = -13.50 D at 90th meridian
3) Adjusted Cylinder power = -5.00 D + VF of +1.50 = -3.50 D
4) Estimated Rx = -9.00 – 3.50 x 180 (Need to ADD -0.25 to cylinder power to obtain the Final Rx)
5) Final Rx = -9.00 – 3.75 x 180

Given: Spectacle Rx for OS: +5.00 – 1.00 x 180. What’s the contact lens Rx?
1) Sphere power = +5.00 D –> +5.00 + vertex factor of +0.25 D = +5.25 D at 180th meridian
2) Sphere + Cylinder power = +5.00 – 1.00 = +4.00 D –> +4.00 + VF of +0.25 = +4.25 D at 90th meridian
3) Adjusted Cylinder power = -1.00 D + VF of +0.25 = -0.75 D
4) Estimated Rx = +5.25 – 0.75 x 180 (Need to ADD -0.25 to cylinder power to obtain the Final Rx)
5) Final Rx = +5.25 – 1.00 x 180

Useful Notes:
a) Spectacle plane –> Contact lens plane
(Remember: “CAP” = Closer ADD Plus!!!)
b) Minus spectacle Rx –> contact lens Rx (CLRx) = expect contact lens Rx to be LESS minus.
Ex: SRx = -4.50 D –> CL Rx = -4.25 D
c) Plus spectacle Rx –> contact lens Rx = expect contact lens Rx to be MORE plus.
Ex: SRx = +5.00 D –> CLRx = +5.25 D
- See more at: http://www.optometrystudents.com/pearl/how-to-rapidly-determine-a-contact-lens-prescription/#sthash.vWKP6NKA.dpuf

Human Eye Structure| Eye Parts & Their functions

Human Eye Anatomy

To understand how the human eye works, first imagine a photographic camera – since cameras were developed very much with the human eye in mind. The eye is a wonderful and the most complex organ of the human body. It is strange to learn that such a small organ has so many parts. The following account provides you information on the parts of the human eye and its function along with the particular functions assigned to each part of it.

The main parts of the human eye & Their Functions

• Cornea: transparent tissue covering the front of the eye that lets light travel through. It is composed of 5 layers of tissue. Its outer layer (the epithelium) provides protection for the eye. The epithelium is made up of highly regenerative cells that have the ability to grow back within 3 days, allowing for fast healing of superficial injuries. Most of the inner layers of the cornea provide strength to the eye.
• Ciliary Muscles: The eye lens is held by ciliary muscles. Ciliary muscles help the eye lens to change its focal length. The ciliary muscle changes the shape of the lens - (this is called accommodation). It relaxes to flatten the lens for distance vision; for close work it contracts rounding out the lens. Everyone will develop an eye condition called presbyopia. As we age, the ciliary muscle and crystalline lens lose their elasticity. This is why most people need reading glasses by their 40’s.
• Conjunctiva:  The conjunctiva is a thin, clear membrane covering the front of the eye and inner eyelids. Cells in this lining produce mucous that helps to lubricate the eye. This is the eyes first layer of protection against infection. Inflammation of this membrane is called conjunctivitis, or pink eye.
• Iris: A ring of muscles in the colored part surrounding the pupil of the eye. The primary function of the iris is to control the size of the pupil. This is achieved through contraction or expansion of the muscles of the iris.
• Pupil: An opening in the center of the iris that changes size to control how much light is entering the eye. This is the black circle in the middle of the eye. When you're in a bright environment, the pupil becomes smaller to allow less light through. When it's dark, the pupil expands to allow more light to reach the back of the eye.
• Sclera: The white part of the eye that is composed of fibrous tissue that protects the inner workings of the eye. The sclera's purpose is to provide structure, strength, and protection to the eye.
• Lens: located directly behind the pupil, it focuses light rays onto the retina. The lens is the clear structure located behind the pupil. Its primary function is to provide fine-tuning for focusing and reading. The lens performs this function by altering its shape. At about the age of 45, the lens becomes less flexible. At about the age of 65, the lens becomes cloudy and hard, preventing light from entering the eye.
• Retina: Membrane at the back of the eye that changes light into nerve signals. The retina consists of fine nerve tissue which lines the inside wall of the eyes and acts like the film in a camera. Its primary function is to transmit images to the brain.
• The Uvea: The uvea forms the center of the eyeball. It is made up of three parts, choroid, ciliary body and iris. The choroid is a thin membrane that is placed between the outer protective sclera and retina. Its function is to prevent the rays of light from bouncing off on the back side of the eye. Malfunctioning of the choroid may cause the formation of confusing images. The role of ciliary body is to assist in the adjustment of the shape of the lens. The iris is described as a separate part in this section of the article.
• Fovea: a tiny spot in the center of the retina that contains only cone cells. It allows us to see things sharply. The fovea is an indentation in the center of the macula. Its diameter is only 1.5 mm or about 1/16 inch. This small part of our retina is responsible for our highest visual acuity. It is the center of our central vision.
• Optic Nerve: a bundle of nerve fibers that carries messages from the eyes to the brain. The optic nerve emerges from the back of the eye, travels through the skull and stops inside the skull bone. From the skull bone, the nerves move through the lateral geniculate body, the internal capsule and ends up at the back of the brain. This part of the brain is known as visual cortex. It is responsible for receiving information from the eyes and interpreting it.
• Macula: a small and highly sensitive part of the retina responsible for central vision, which allows a person to see shapes, colors, and details clearly and sharply. This part of the retina is the most sensitive. Its diameter is only 7 mm or about 1/4 inch. It is responsible for our central, or reading vision. This part of the retina gives us 20/20 vision. Without the macula, you would be blind - Legally blind that is. People with eye diseases like Macular Degeneration have vision from 20/200 to 20/800.
•  Vitreous Cavity: The space between the lens and retina filled with the gel like Vitreous Humor.

How Human Eye works

Light reflects off of objects and enters the eyeball through a transparent layer of tissue at the front of the eye called the cornea. The cornea accepts widely divergent light rays and bends them through the pupil – the dark opening in the center of the colored portion of the eye.

The pupil appears to expand or contract automatically based on the intensity of the light entering the eye. In truth, this action is controlled by the iris – a ring of muscles within the colored portion of the eye that adjusts the pupil opening based on the intensity of light. 

The adjusted light passes through the lens of the eye. Located behind the pupil, the lens automatically adjusts the path of the light and brings it into sharp focus onto the receiving area at back of the eye – the retina.

An amazing membrane full of photoreceptors "rods and cones", the retina converts the light rays into electrical impulses. These then travel through the optic nerve at the back of the eye to the brain, where an image is finally perceived.

Since both the eyes are separated by the nose, they have different fields of vision. Due to the difference in the visual fields, each eye sees at different angles of the object, and so gives different information to the brain. Along the way at the optic chiasma, some of the nerves from each optic nerve cross over so as to separately collect the information from the left and right side of the field of vision. 
The swapping of information takes place one more time at the cell station. This connection works in accordance with the reflexes of the pupils. The information is now received by the visual cortex, which interprets the image at this point.

Toric lenses | Contact Lenses for Astigmatism | Benefits of TL

Toric Lenses & Astigmatism

 ( Will Contact Lenses  be a Solution or Not?)

Toric lenses are contact lenses are used to correct astigmatism; a refractive error in the eye caused by an imperfect curvature of the cornea. When light enters the eye, it is not focused properly on the retina, resulting in distortion. The most common symptoms of this condition are blurred vision, sensitivity to light, squinting, headaches and eye strain.

A common eye condition known as an astigmatism often goes undetected because of the minimal effect it has on a patient's vision. Some astigmatisms can lead to blurred or impaired vision if they become moderate or severe. The cause of the blurred and impaired vision is the result of the eye's cornea or lens having an irregular shape. In a normal eye the cornea has a circular shape, whereas corneas with an astigmatism have a longer oval shape.

There are many approaches to correcting astigmatism for the contact lens wearer. One of the most common approaches has been to ignore astigmatic error, applying spherical equivalent correction. This is a legitimate approach for low amounts of astigmatism or situations where simplicity and cost are of higher priority than acuity. Performance in sports such as soccer or hockey, for example, while requiring good vision, is not likely to suffer due to a visual acuity that is not a perfect 20/20.

The design of a toric lens ensures that the lens does not rotate in your eye if you blink or move your eyes. This is necessary as toric lenses contain two powers perpendicular to each other, one to correct the astigmatism (CYL/Cylinder) and the other to correct either short-sightedness or far-sightedness (SPH/Power).

The selection of toric lens parameters is steadily increasing year by year, most notably in the range of available cylinders for monthly replacement toric lenses and axis measurements for daily replacement, single use toric lenses and silicone hydrogel torics. The manufacturing process for toric lenses is more complex and this is reflected in higher prices compared to standard soft contact lenses.

Unlike spherical lenses, toric lenses are designed not to rotate on the eye. Continual exposure of the inferior front surface of the lens to drying during the inter-blink interval could lead to deposit formation but the surface technology applied to some silicone hydrogel lenses renders them highly deposit resistant, especially for protein. Despite this advantage, some silicone hydrogels have been prone to lipid deposition particularly when a surface treatment is not used.

Lipids can diffuse into the lens matrix and cannot be extracted by lens care solution surfactants, leading to regions of reduced lens wettability. This response can vary between individuals and while deposition of native tear film lipid is important for lens lubrication, a buildup of oxidized lipid deposits can be problematic, leading to contact lens discomfort and intolerance. The addition of a ‘rub and rinse’ step to the lens care regimen is important for these wearers, especially in non-surface treated lenses.

Toric Contact lenses Advantages & Disadvantages 

The advantages of a soft toric contact lens include easy adaptability, as comfort is usually quite good even initially. Other advantages of soft toric lenses include:

• Extended wear option –allowing up to thirty days of continuous (overnight) wear.
• Eye color –soft torics are available in various colors that can change even the darkest eyes to a variety of colors.
• Convenient replacement schedules –conventional lenses allow you keep the same lenses for a year, or the more common "disposable lenses' allow you to wear for one month, 2 weeks, or only once and throw away, with no need to ever clean them.
• One of the chief benefits of fitting a toric lens is the improvement in vision over a spherical lens. Even for low levels of cylinder, the improvement can be significant. A three to 5.5 letter improvement in vision compared to the spherical equivalent or ‘masking’ was observed for low astigmats (≤1.00 DC) and 8.5 up to 12 letters of acuity improvement was observed in high astigmats (1.25 to 2.00 DC) when they were fitted with toric lenses rather than sphere (P<0.05). A one or two line improvement in visual acuity shows the visual benefits the practitioner can offer are significant, even for a low astigmat.

Their biggest disadvantage is the potential for fluctuating vision. No matter how good the lens design and fit, all soft toric lenses rotate and move a bit in the eye. As explained earlier, this can be a source of frustration when you can see clearly one minute, and are blurry the next. The more astigmatism a person has, the more likely he/she will be sensitive to the lens movement.

Conclusion

When choosing a toric lens, consider your patient's history, needs and demands in addition to optical and physical requirements. Previous contact lens wear experiences will also provide valuable clues to help you develop a successful contact lens program. Demands of perfect vision or perfect comfort, as well as occupational or athletic needs will guide you in your first decision: whether to proceed with a soft lens or a rigid lens.

Pink Eye Symptoms & Contact Lenses| Causes | How to treat

UnderStanding Pink Eye Symptoms & Contact Lenses

Pink eye, also known as conjunctivitis, is an inflammation of the conjunctiva. Conjunctivitis literally means "inflammation of the conjunctiva". The conjunctiva is a thin membrane containing tiny blood vessels and produces mucus to coat and lubricate the surface of your eye. When the conjunctiva becomes irritated or inflamed, the blood vessels become larger and more prominent, making your eye appear red.

Conjunctivitis may occur in one or both eyes. Conjunctivitis can cause swelling, itching, burning, discharge and redness of the protective membrane that lines the eyelids and covers exposed areas of the white of the eye.

The conjunctiva is a thin membrane that covers the whites of your eyes by coating it in a mucus to lubricate the surface, helping to protect it. Pink eye can be caused by a number of things from bacteria, viruses, allergies to other environmental irritants. Regardless of the cause it can be extremely contagious. Symptoms usually include red eye, itchiness, a scratching and/or burning feeling.

Different Causes of Pink Eye Symptoms

It occurs when our conjunctiva is inflamed due to infection. (If you're like me and don't know what conjunctiva means at first, it's the part where your eyeball and eyelids meet). The three most common forms of pink eye are viral, allergic and bacterial.

When this happens, your eyes appear red, watery and you also feel irritated. Sometimes, your eyes may feel itchy as well.

Causes of pink eye which, for contact lens wearers, can be:

• Use of extended wear contact lenses. Bacteria can build up underneath lenses that have been in the eye for long periods of time.
• Poor hygiene. Failure to wash hands properly before inserting or removing lenses, or laziness when it comes to changing your contact lens solution, can all cause eye infections, as bacteria gets into the eye and onto the lens. 
• Trying to save money by NOT changing disposable lenses after the required time period can also result in pink eye. This is as much due to eye irritation initially, but an itchy eye can soon become an infected one if you don't listen to your body and throw away those lenses as soon as your eyes begin to itch.
• Allergies can, of course, affect contact lens wearers who may be susceptible to high levels of pollen or a windy day may just blow grit into your eyes, resulting in red swollen eyes. 

How to treat Pink Eye Symptoms Naturally & Other Ways to treat it.

The best tip I can offer as a contact lens wearer for avoiding pink eye symptoms, is to ALWAYS change your disposable lenses according to the maximum wear time. Don't try and save money by wearing those daily disposables for an extra day or two or extend your 1 week lenses to 2 weeks.

• Put damp herbal teabags like chamomile or elder-flower (after they have been used to make tea) onto the eyelids and lie down for half an hour. 
• Place a tablespoon of chamomile flowers in a cup of boiling water, infuse the solution for 10 minutes, remove the petals, and then allow the solution to cool. It makes a great cooling eye-wash that really helps to relieve pink eye. 
• Soak some cotton wool pads in warm milk that has first been boiled to kill any bacteria that may be present. Pop them onto your eyelids and lie down for half an hour to let the compress soothe your eyes.

Only the bacterial causes of pink eye can be treated with antibiotics. If it is a bacterial irritant that has caused your symptoms there is usually puss present. Viral and other causes will most often clear up on their own without damaging your eyes, however it is always recommended to see an ophthalmologist to confirm your symptoms.

While severe bacterial forms of conjunctivitis or pink eye need to be treated with antibacterial eye creams or eye drops, sometimes, you just can't get to a chemist or an eye doctor, or your eyes may be so swollen and painful, you don't want to go out or you simply cannot drive.

Contact Lens Prescription | How to decode Eg -1.25 | Terminology

A contact lens prescription has a series of fields that are not included on your eyeglass prescription. These fields signify important aspects, like the curvature and depth of the contact, to ensure that your contact lenses fit and function properly. Eye doctors use standard terms, abbreviations and measurements to write contact lens prescriptions. It may look like a secret code, but it's really quite simple to decipher. The prescription may also have an expiration date, brand name, and other fields, but most of these are optional by the doctor. By using these universal terms to describe ocular imperfections, prescriptions can be interpreted by eye doctors around the world.

Understanding Contact Lens Prescription & Terminology Used in this Test 

Contact Lens Prescription

Eye: - Which eyes the prescription line item is for.

• OD - Right Eye 
• OS - Left Eye
• OU - Both Eyes
• R - indicates the right eye. Sometimes written as O.D. 
• L - indicates the left eye. Sometimes written as O.S. 

Brand: - The brand/type of contact lens that your doctor has fitted you for. In the United States, lens prescriptions always indicate a specific brand. The law states that US retailers must sell you that brand and no other. In the case of a “private label”, contact lenses that are sold only by eye care professionals, substitutions of an equivalent natural brand or private label brand may be permissible.

Power sign Either + (plus) or - (minus). Power, the diopter measurement needed to correct your vision.

Contact Lens Prescription Terminology

Sphere (Sph): - Sphere (this can also be referred to as Power or PWR), is a number between +20.00 and -20.00. Plano means the lens has no optical power and does not correct vision. The number might be very small, like 0.25, or a large number, like 6.00. The higher the number, the stronger the prescription lenses required. This can influence your choice of frames. The higher the prescription, the greater the curve of the lens needed.

Cylinder (CYL): - It is a number between -0.50 and -4.00 and is only found in Toric Prescriptions to correct astigmatism. Measured in diopters, the cylinder shows the extent of your astigmatism. A negative sign means Myopia (nearsightedness) astigmatism and a plus sign means Hyperopia (farsightedness) astigmatism.

Axis (Axis): - is a number between 1 and 180 and is only found in Toric Prescriptions to correct astigmatism. The axis is measured in degrees and indicates the orientation of the cylinder in the lens and is used in order to compensate for the cornea’s oval, rather than round, shape. The number is not related to how well you can see but it helps the lab know what angle to position your lenses in the frame.
Often the Sphere , Cylinder and Axis of prescriptions will be written all together in the following form: SPH / CYL x AXIS and will look something like -1.00/-0.75 x 90.

ADD: - is a number between +0.50 and +4.00 only found in Bifocal or Multifocal lens prescriptions. If you are over 45, there may be a number where it says ‘ADD’. This is your reading addition and relates to the amount of additional correction needed to focus at close distances. If a measurement is shown in this section, it means you have different prescriptions for distance and reading. Bifocal or varifocal lenses may be needed.

Base Curve (BC): - Curve (usually a number between 8 and 10), Number between 7.0 and 9.5 which determines the looseness or tightness of a contact lens. It’s the back curvature of your contact lens and is measured in millimeters. For best fit, comfort and eye health it’s prescribed to match or complement the curvature of you cornea. The lower the number, the steeper your cornea.

Diameter (DIA): - Diameter (usually a number between 13 and 15), Number between 13.0 and 15.0 and is the diameter of the contact lens. It’s the distance, measured in millimeters, from one edge of your contact lens to the other edge. It’s important because it determines where on your eye the edges of the lens will rest. If the diameter is wrong, it can cause irritation and/or abrasions.

Lens Tinting: - This is the tint or colour of the contact lens. Some lenses are clear and most have a very light tint called a visitant which allows you to see the contact lens slightly more easily when handling it. Tinted contact lenses have a variety of colors to choose from to change your natural eye colour.

Conclusion

As we know a contact lens is a thin lens, made of flexible or rigid plastic, that is placed directly on to the eye to correct vision, used as an alternative to spectacles, or, if colored, to change one's eye color cosmetically. It is a corrective, cosmetic, or therapeutic lens usually placed on the cornea of the eye.

Contact lenses are more versatile than glasses making it easier to participate in a number of outdoor activities and sports such as jogging, golf, tennis, skiing or skating. By wearing contact lenses you now have the option of choosing from a variety of non-prescription sunglasses for sport and fashion.

Your doctor will recommend the best contact lenses for your eyes based on a complete eye examination and a review of your visual needs both at work and play. Success with contact lenses depends upon a certain amount of motivation and a commitment on your part. You must learn to take proper care of both the lenses and your eyes.

 

Contact Lenses Prescription (-1.25 ) | What & Why it is Needed?

Understanding Contact Lenses & Eye Glass Prescription 

Prescriptions last one to two years, depending on the minimum required by state law and even though prescriptions for contact lenses and glasses are similar, they should never be used for one another. Once your prescription has expired, you must be refitted to gain a new prescription, and to be able to purchase new lenses. Your contact lens prescription contains specific information to ensure your contact lenses are safe, comfortable and provide optimum vision.

If you're in the U.S., your contact lens prescription is yours to keep. In fact, by law your eye care practitioner must give you a copy of your prescription at the conclusion of your contact lens exam and fitting — even if you don't ask for it.


If an eye care practitioner is seeing a patient for the first time, vision is usually checked without any correction and this is noted in the chart. Next, refraction is performed. A refraction is the process of determining one’s glasses (or contact lens) prescription, which is typically completed as the patient looks through a device known as the phoropter. Once you've been properly fitted by your eye doctor and have a valid contact lens prescription, you have the option of buying contact lenses from a wide variety of sources.

Is Contact Lens Prescription is Different from eyeglass prescription?

How do you read a contact lens prescription? Your contact lens prescription is significantly different from your eyeglass prescription. Although some of the numbers and measurements are the same, a contact lens prescription has a series of fields that are not included on your eyeglass prescription. In addition to the lens power, your contact lens prescription contains several other pieces of information related to the size of the lens. These fields signify important aspects, like the curvature and depth of the contact, to ensure that your contact lenses fit and function properly. For this reason, your eyeglass prescription cannot substitute for your contact lens prescription, and vice versa.

Why one should take precaution in case of Contact Lenses?

A contact lens is a medical device, and a poorly fitted lens — or one made from a material not well-suited to your eyes — can cause distorted vision, discomfort, infection, inflammation, swelling and abrasion. In rare cases, permanent eye tissue damage could result. And it goes without saying that you should never share your contact lenses, including colored contacts and theatrical contacts. Sharing contact lenses can cause potentially sight-threatening eye problems.

Remember, if you're diagnosed with a lens-related problem, it's unlikely that you'll have to permanently discontinue wearing contacts. Chances are you'll simply need a different size, material or design of lens. Wherever you choose to purchase your contact lenses, always make sure you buy your contacts from a legitimate source.

Read Here >>> Contact Lens Rule - Federal Trade Commission

Contact Lenses | Benefits | Uses | What is It?

Contact Lenses

Contact lenses are closer to natural sight than eyeglasses. They move with your eye and correct the refractive error closer to the eye to allow for a more natural field of vision. They don't get in the way of your line of sight, like glasses can. Contact lenses can be worn all day, or even several weeks at a time, so you don't have to worry about putting them on and taking them off.

What is the Principal Behind Contact Lenses

The principles of refraction and related to optics are similarly applied to contact lenses. This contains the correction of current defect by replacing the contact lens surface with corneal curvature which accured in accordance with the degree of myopia and hypermetropia. Since the major part of astigmatic defects develop due to the distortion of frontal layer of cornea, either hard or special soft lenses produced only for astigmatism shall be used. 

Cases In which Contact Lenses are Used

Farsightedness / Hyperopia: -  People with hyperopia can see clearly far away, but their close-up vision is blurry. To correct hyperopia, the lens is thicker at the center and thinner at the edges. These lenses are called plus, or convex. The lens bends the light toward the center and moves the focal point back so that light is focused on, rather than behind, the retina.

2 Types of Contact Lenses

• The Gas permeable hard lenses
• Soft Lenses   

Contact lenses are not one-size-fits-all, and constant "lens awareness" could indicate a poorly fitting lens. Lenses come in thousands of combinations of diameter and curvature. If your lenses have the wrong diameter or curve, you'll likely feel that something is always in your eye. If the lenses are too large, your eyelids will tend to dislodge them when you blink. The wrong size lenses can even cause abrasion of your cornea.

Wearing contact lenses should be a comfortable alternative to wearing regular glasses to aid in improving vision.  Yet sometimes people don't receive the desired benefits of wearing contact lenses.  So Make sure you are not getting any problem after wearing Contact lenses.