• Your corneas
    Eye Health

    Cornea at the Corners – Function & Facts

    The cornea is the transparent part of the eye through which you can see the iris and pupil. The outermost layer of the eye is composed of the sclera (white part of the eye) and the cornea. The outermost layer of the eye extends as the white sclera from behind the eye until the front of the eye where it becomes transparent and formed by the cornea. The cornea form one-sixth of the eye’s outer layer.

    What’s the main function of the cornea?

    The function of the cornea is to refract “bend” entering light rays to the eye to make them focused and forming images. Its power of focusing light rays (with the power of eye’s lens) determines where the light rays will be focused in the eye. The more the power, the shorter the distance in which light rays are focused.

    The cornea contributes about two-thirds of the whole refractive power (ability to focus light rays) of the eye. The power of the cornea is not the same in all people, like those who are prescribed with monthly Biofinity lenses. When the power of the cornea increases, the distance in which it focuses light rays decreases. Normal corneal power focuses light rays on the retina. If the corneal power is more than normal, light rays are focused in front of the retina. If the cornea has less power than normal, light rays focused behind the retina.

    The main factor that determines the refractive power amount of the cornea is its curvature.

    – The cornea is curved in two perpendicular meridians. When the two meridians have different curvatures, the cornea takes the shape of the basketball. When the two meridians have the same curvature, the cornea takes round shape like the football and contact lenses that have marked down prices should be able to attach to it without issues.

    – The more the curvature of the cornea, the more the power it has. Steeply-curved corneas refract light rays more and focus them in shorter distances than less curved corneas.

    – When the two meridians of the cornea have the same curvature, they have the same refractive power. They focus light rays on the same plane in the eye. This happens in the normal eye, myopia, and hypermetropia like in the below image.
    Diagram of refractive issues in the eye
    – When the curvature is different in the two corneal meridians, they have different refractive power from each other. So, they focus light rays into two different distances (planes) in the eye. This happens in astigmatism like in the image below.

    Normal vs Astimatic EyeThe cornea and the eye’s lens constitute all the refractive power of the eye. So, the location of the images in the eye is determined by the sum of the two powers.

    Facts about the cornea

    – The cornea is the most sentient part of the body. It is innervated by dense nerve fibers. It is very sensitive to any approaching movement or object. Its nerves send signals to close the eyelids immediately if anything approaches.

    – The cornea has no blood vessels. It gets nutrition and oxygen from the tears of the eye and the aqueous humor.

    – The cornea is transparent because it has no blood vessels. Also, the nerve fibers in the cornea are demyelinated keeping it transparent.

  • contact lenses can cause corneal abrasion
    Eye Health

    Contact Lenses and Reshaping the Cornea

    Contact lenses sit on the surface of the eye over the cornea. The lenses can be made of a soft silicone material or a rigid material called gas permeable or hard, PMMA lenses. Both types of lens material, if worn improperly or for too long, can cause the cornea to change shape.

    Understanding Why the Shape of The Cornea is Important for Contact Lens Wearers

    The cornea is the thin, clear outer layer of the eye. Light passes through the cornea and through the crystalline lens of the eye and to the retina. Wearing contact lenses can sometimes change the shape of the eye. When this happens, many problems can occur within the eye, including oxygen deprivation, vascular problems, and even altered vision.

    When a person first gets their contact lenses, the eye doctor measures the cornea with a tool called a keratometer. This machine measures the surface of the eye, and the doctor uses the measurements to prescribe a lens designed to fit the front surface of the eye. Proper fit is important for both good vision and good eye health.

    How Contact Lens Wearers Can Avoid Reshaping the Cornea

    Maintaining hygiene and resting your eyesTo help reshape a warped cornea or avoid a cornea becoming damaged:

    • Make sure the lenses are sitting on the eye properly. The best way to tell if the lens is correctly on the eye is to have the eye doctor or contact lens technician recheck the fit. This can be done quickly in a short appointment called a recheck. Lenses can tighten and loosen after wearing them for several weeks or months.
    • Give the eyes a break. Wearing time, the length of time per day lenses are permitted to be worn, varies depending on the type of lens and individual, general eye health. An eye care professional determines the proper wearing time during the initial contact lens fitting. Wearing lenses too long can affect the cornea through lack of oxygen to the eye. Following the wearing schedule and wearing glasses occasionally gives the eyes a time to rest and breathe.
    • Inspect contact lenses regularly for tears, cracks or rips. A lens can be damaged but not feel any different. Wearing damaged lenses can affect fit and cause corneal problems.
    • Practice proper lens hygiene. Cleaning all types of contact lenses regularly helps avoid deposits that can accumulate on the surface of the contacts. If lenses are continued to be worn, there is a risk of potentially serious side effects including corneal damage.
    • Follow a regular exam schedule. Contact lenses are a medical device and are regulated by law for patient protection with expiration dates. Wearing expired lenses can potentially cause many problems, including corneal fit.

    Corneal Reshaping with Contacts Can Be Intentional

    Recently, eye doctors have been using a technique to intentionally reshape the cornea through Orthokeratology (Ortho-K) or Corneal Refractive Therapy (CRT). This is done by wearing a special contact lens at night that gently reshapes the surface of the eye, but the results are temporary and must be repeated each night. This procedure is usually used on people who are nearsighted.

    Contact lenses are one of the most common medical devices used today. They are convenient and fairly easy to use. Properly wearing the lenses and taking good care of them is key to avoiding problems such as corneal swelling or reshaping.

  • Eye Health

    The Ties that Bind Eye Color and Personality

    Changing your eye color can do more than just change your appearance. Understanding how color affects personality, mood and other people’s perceptions is still in its infancy. Nonetheless, a mounting body of research points to the fact that color can be used to convey a message.

    Artists, advertisers and even police understand this. Think about why a fire engine is red. Because red, apart from the fact that it stands out, conveys a sense of urgency or excitement.

    It was found that when the employees of a film laboratory in Lyon France worked all day bathed in red light, they were lively and animated. When they switched to green light, these same employees became less tired and much calmer.

    “The eyes are the windows to the soul. “It may be a clichéd phrase these days, but recent research adds support to the belief that eye color indicates something about one’s personality.

    Personalities connected to specific eye colorsResearch and People’s Perception of Eye Color

    The Impulse Research Corporation in Los Angeles conducted a survey; they polled 1,016 women aged between 16 and 35. The results indicated that people often associate different eye colors with specific personality traits.

    The following is a summary of the results:

    Brown Eyes

    34% of survey respondents thought that brown eyes indicated an intelligent personality. While 16% thought brown-eyed people were trustworthy and 13% indicated kindness as a significant personality trait. Qualities they least associated with brown-eyed individuals were shyness (6 percent) and creativity (4 percent).

    Blue Eyes

    42% of individuals survey though that blue-eyed people exuded sweetness, with other traits being, sexy (21%) and kind (10%).

    In contrast to brown eyes, only 7% of those surveyed thought of blue-eyed individuals as intelligent.

    Green Eyes

    25% of respondents associated green eyes with sexiness while other perceived traits were creativity (25%0 and surprisingly devious (20%). Green-eyed people are not considered trustworthy with only 3%. Unlike blue eyes only 4% of those surveyed associated green eyes with being sweet.

    This study is not alone in trying to establish a link between eye color and personality. Other studies have indicated that blue-eyed children have the propensity to have more behavioral inhibitions compared to their brown-eyed counterparts. Among kids who suffer from stuttering, those with blue eyes have more deficiency in their speech processes. Also, there have been studies in the past which found the connection of eye color to factors of medical prognosis that could predict pathological vulnerabilities. Eye color has even been studied to foresee alcoholism occurrence in adulthood.

    You may dismiss all this as mystic waffle or alternative crap, but according to research at Bloomsburg University, color affects mood, even to the extent that some therapies use color as part of their healing practices. While religion has for centuries used color to symbolize emotions and beliefs. In advertising, it is well known that color influences a buyer’s behavior and that color possess a meaning.

    What Does Eye Color Mean to Me?

    So, once you have an understanding of all this, it’s no surprise that changing your eye color can make a big difference to how people perceive and react. It can be far more than just a simple cosmetic change. When you gaze into someone’s eyes, you’re subconsciously making a judgment about that person. And psychologist has known for many years that the subconscious plays a big part in our daily lives. Shaping much of our behavior.

    Our initial reaction when we meet someone for the first time plays a big part in how we react. Wouldn’t it be fun to experiment with this? Colored contact lenses may be the answer. Imagine if by just wearing a pair of $30 brown contact lenses you could alter other people perceptions.

    Cosmetic eyewear like brown contact lenses is not just for women either. Ask most girls, and they are likely to confess that the eyes are the feature they find most attractive in a guy.

    Colored contact lenses have never been more affordable and easier to use than they are today. If you think you have trouble meeting people, changing your eye color may be worth it. Let’s face it it’s a whole lot easy than dieting and much more proactive than sitting in front of a mirror obsessed with the fact that your nose is too big, or your breasts are too small. For the costs of a couple of movie tickets, you could conduct your own experiment. Get out there and try.

  • Loving your eyes
    Eye Health

    Maintaining Eye Health

    Almost 80% of what we perceive through our sensory abilities comes from our sight. Protect your vision with everyday care for your eyes and overall health.

    Smoking not only causes irritating smoke that harm the eyes (and causes a host of other serious health problems); medical studies show that the density of eye pigments in the retina that is essential to healthy vision actually decreased as smoking increased. These eye pigments are called macular pigments and also protect the retina by their antioxidant capabilities and by shielding the eyes from harmful UV radiation. Smoking ultimately increases the risk of eye disorders including cataracts, dry eyes, macular degeneration, and retinopathy.

    Bright healthy eyes need careVitamin Benefits

    Vitamins A, C, and E all offer benefits for overall eye health. Vitamin A can help to reduce the risks of cataracts and night blindness, and a deficiency has been implicated in blindness and corneal ulcers. Vitamin C reduces pressure in glaucoma, slows age-related degeneration (AMD) and prevents cataracts. Vitamin C is also a strong antioxidant that is highly concentrated in the lens of the eye and used by the muscles of the eye. Vitamin E helps to reduce the risk of macular degeneration and cataracts. Often obtained from leafy, dark green or orange vegetables, Vitamin A could be sourced from spinach, carrots, and in some animal products. Crucial sources of vitamin E include nuts such as almonds, seeds, grains, green leafy vegetables, and vegetable oils.

    Two important antioxidants for eye health that must be acquired in the diet are lutein and zeaxanthin. They are found in leafy, green vegetables such as spinach, kale, and fresh parsley; and yellow fruits and vegetables such as squash and corn.

    Minerals are needed to help the body metabolize vitamins and balance nutrition and hormones. Critical minerals for eye health include zinc and selenium. Other important supplements for eye health are lutein, bioflavonoids, and carotenoids.

    Natural supplements for eye health include bilberry, which contains antioxidant compounds that help maintain the strength and structure of eye capillaries. Grape seed extract is a powerful natural antioxidant. Proanthocyanidins are also recommended for their powerful vascular strengthening abilities and antioxidant activity.

    Eye Health Tips

    • Wear a pair of ultraviolet proof sunglasses whenever you are outdoors, even on cloudy days. Doctors recommend wearing sunglasses all year round, not just during the summer.
    • Eat a healthy diet: fresh deep green leafy vegetables, fruits and whole grains, deep-water fish, eggs, chicken and turkey with little red meat. Avoid refined, processed foods high in sugar, white flour, hydrogenated oils, artificial flavorings, and colorings. Eat plenty of berries, watermelon, carrots, citrus fruits, almonds, and olive oil.
    • Avoid toxins that are used in foods such as aspartame, MSG, steroids, and hormones.
    • If you have diabetes, keep blood sugar levels under strict control and get regular checkups.