Posts Tagged ‘surface’

How to Relieve Dry Eye Caused By Lasik Surgery

Dry eye is a common eye problem, and there are many causes of dry eyes, one of which is the postoperative side effect of Lasik surgery. In normal circumstances, Lasik surgery, some studies show that, is one of the main causes of dry eye, although sometimes certain people seem to experience no dry eye symptoms.

Reasons why Lasik surgery leads to dry eye are as follows. In the process of a Lasik procedure, there must be a corneal flap created by either a steel blade or a laser, during which the corneal tissue and corneal nerves are supposed to be broken up. What is more, the following reshaping of corneal by laser will come to further disrupt the nerve tissue. If the patient suffer from a comparatively more seriously eyesight problem, the nerve tissue is thought to be cut deeper, which does more side effect to eyes. Then due to the whole disruption, the nerve tissue, when recovering and regenerating, is normally hard to produce tears to keep eyes moistened. Thus dry eye symptoms emerge.

( What is more, for supplement only, whether the corneal surface and tear lay are created to be qualified or smooth is closely related to another eyesight problem of “ghosting” and “fuzziness”, as when light comes into eyes, it meet with the tear layer at the very first. If the corneal surface or tear layer is of irregularity and deficiency, visual acuity will be greatly affected.)

As a surgeon, considering the possible side effects of dry eyes, and ghosting or fuzziness images creation, I advise several ways to minimize those possibilities after operation: have an overall examination concerning eyes, including the evaluation of preexisting dry problems; apply the Intralase FS lasers, but not the steel razor blade microkeratome to create the corneal flap, which is believed to be more able to minimize unsmooth and unqualified corneal surface and tear layer; after the surgery, use artificial tears and gel lubricants for a series of days. Those who do not have the experience of dry eyes after lasik surgery are also suggested to. The cyclosporine 0.05% eye drops (Restasis) are recommended.

It has been researched that the above regimens are able to relieve dry eyes, as well as other eye problem after Lasik surgery. By persisting in the regimens, improvement of eyesight, but also the prevention from secondary side effects can be guaranteed. Besides, get more information of Lasik surgery in advance is also helpful to enhance the outcomes.

more info

·Dry eye causes and treatments

·Flaxseed oil for dry eye treatment

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Article Source:http://www.articlesbase.com/vision-articles/how-to-relieve-dry-eye-caused-by-lasik-surgery-1697531.html

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How Did Contact Lens First Came About?

The idea of placing corrective lenses right or directly at the surface of the cornea of the eye is not really a post modern eye care innovation thing; hence its original blue print can be dated way back in high Renaissance period where the famous Florentine artist Leonardo Da Vinci sketched the idea of first contact lens that will aid vision and change human eye’s corneal power.

Past versions or models of contacts are in fact unwieldy and uncomfortable to use for it is made up of fine glass. But today’s contact models offer both comfort and style as it never fails to aid vision and help people (especially young people )deal with various eye and vision problems.

It was in 1630s when a French Philosopher under the name René Descartes proposed the idea of using the lens, placing it directly right at the surface of the cornea. He proposed in the invention of liquid-filled glass tube to aid poor eye vision.

At 1801, a scientist named Thomas Young developed René Descartes’ proposal by operating experiments with the use of liquid-filled eye cups, which outer end contained a microscopic lens.

John Herschel in 19th century then proposed the same idea with the use of jelly-filled capsule and corneal mould. Though it was said that Herschel never tested his idea at first place, his proposal was then used in various studies and experiments for the development of today’s modern version of contacts. His proposal has even led to the invention of the lens that can shape and fit the eye.

After 40 years, a German under the name of F.E. Muller made the first usable contacts that are made up of glass. These are of course, not very comfortable to wear, and in fact painful to the eyes when worn for hours.

Since then, its history has got a long way, and various experiments and studies have been conducted to develop Da Vinci’s contact lens concept. Various changes are made for different purpose or use of contact lens. Nowadays, we can find not only corrective contacts for the eyes but also colored contacts for fashion purposes.

The Author is an expert in article writing and has done a lot of research online and offline. Come visit his latest websites on Cheap Contact Lens and Acuvue Color Contacts

Article Source:http://www.articlesbase.com/vision-articles/how-did-contact-lens-first-came-about-1675260.html

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Refractive Laser Surgery

Refractive laser surgery is usually performed for correcting common ailments of the eye such as myopia and astigmatism. All refractive surgeries do not employ the use of laser. Some surgeries such as Radial Keratotomy (RK) do not employ laser although they are equally effective in curing refractive ailments of the eye. Some common types of refractive laser eye surgery include Lasik, PRK and LASEK.

Common Method of Refractive Laser Surgery
There are various methods employed for refractive laser eye surgery. These are divided into flab procedures and surface procedures.
* Flap Procedures: In such surgeries, a particular type of blade known as microkeratome is used for cutting a flap in the corneal tissue. The most common example of surgery under this method is called Lasik.
* Surface Procedures: In this process an excimer laser is employed for removing the front portion of the corneal stroma. Unlike the flap method this approach does not require the partial thickness cut in the stroma. Thus differentiating this method of handling the epithelial layer from the flap method. Photorefractive Keratectomy (PRK) and Laser Assisted Sub-Epithelium Keratomileusis (LASEK) are two common examples of surface procedures of refractive laser surgery.     

Examples of Refractive Laser Surgery
Lasik: This acronym stands for Laser Assisted In-Situ Keratomileusis. In this surgery, a flap is cut with the help of microkeratome blade. The thickness of such flap could be between 100 to 180 micrometers. The flap is then lifted and an excimer laser is used to remove the targeted tissues from the corneal stroma. The flap is then replaced after the removal of the unwanted tissues.
IntraLasik is another variant of this surgery. In this method the flap is cut with the help of laser. Where a microkeratome blade is used to create the flap, the proceedure is known as “traditional Lasik” in order to differentiate it from other forms of refractive laser surgery.
PRK: Photorefractive Keratectomy (PRK) was widely used for correcting the vision problems before the popularity of Lasik. In this surgery, the paitents recovery time takes longer than with Lasik.
LASEK: It stands for Laser Assisted Sub-Epithelium Keratomileusis and in this surgery, surface methods is used for correcting the vision problem.

The Laser Eye Center of Silicon Valley specializes in refractive laser surgery. This vision correction center specializes in all forms of Lasik, PRK and LASEK refractive laser eye surgeries.

Welcome to Laser Eye Center of Silicon Valley, one of the finest refractive laser surger centers in California.

Article Source:http://www.articlesbase.com/vision-articles/refractive-laser-surgery-1621454.html

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Ergonomic Benefits of Using a Reading and Writing Slant Board

There’s a reason why school desks used to be slanted back in the old days. Unfortunately, most of today’s classrooms seem to have forgotten what that reason is. Educators recognized a long time ago the benefits of using a slanted surface to read and write. Slanted surfaces make both activities easier for students, facilitating learning and preventing posture and vision problems. It is all based on ergonomics, the science of designing work and learning equipment and environments so that they fit human beings in a way that is optimal both to the health of the worker/student as well as his or her productivity/learning ability.

In terms of reading and writing, the ergonomics of slanted surfaces is based on the simple fact that, when we are reading, we have a natural tendency to tilt the material towards us. It is more comfortable to have material slanted towards you. Using a slanted writing and reading surface automatically lets the letters on the page come into focus better without needing to strain you eyes. It also lets you track lines with greater ease and keeps letters and numbers in a consistent perspective as you make your way down the page.

The result of all these factors is that your brain doesn’t have to work as hard at interpreting the written symbols, thus leaving it with more resources to actually comprehend, learn and analyze what it has just read. This also means you are less mentally fatigued by the end of a reading/study/writing session.

Buy a whiteboard. Reading and writing slant boards being sold today are created with the intent of providing students and people in general with an optimal environment in which to work and study. Pioneering studies, the results of which have been published in scientific journals like the American Journal of Optometry Archive, have shown that there is a strong relationship between a person’s learning/working efficiency and his/her posture, work distance and work surface.

Learning performance improves especially when the right conditions are established during near-point visual activities, i.e. reading and writing. To this end, the optimal angle for reading and writing surfaces has been found to be between 20 and 23 degrees, with the person sitting at a fist-to-elbow distance from the working surface.

Adjustable slant boards let you find your optimal angle. Many slant boards also come with additional built-in features like a whiteboard, so that you won’t need to buy a whiteboards separately. A proper reading and writing set-up will help reduce your heart rate, help you maintain a better breathing pattern and reduce neck and body tension by compelling you to sit using proper posture.

Ryan Frank is a 23 year writer and blogger living in San Diego, CA.

Article Source:http://www.articlesbase.com/vision-articles/ergonomic-benefits-of-using-a-reading-and-writing-slant-board-1374247.html

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Contact lenses for personalized needs

People may need customized contact lenses if they have special eyes or high astigmatism, or they just need additional comfort and particular clear vision. Both RGPs and soft lenses are available for people’s personalized needs.

RGPs are commonly acknowledged that they provide clearer vision than soft lenses, especially for astigmatism. However, most of the traditional RGPs have a slight gap between the lens edge and the eye surface, in order to allow more oxygen in tears during blinking. It is still this special design which may make people uncomfortable, especially for those with irregular eye surface shapes. In this case, customized RGPs are designed to tackle this dilemma, which have different measurements and lens designs.

For conventional RGPs, an instrument called keratometer is used to measure the cornea’s curvature. And the curvature of conventional RGPs has three elements: the curve of the steepest meridian, the curve of the flattest meridian and the orientation of the flattest meridian. These measurements help doctors or manufacturers determine the curves of RGPs’ back surface. Conventional RGPs always have a central curve and two periphery flatter curves.

Custom RGPs require more complex eye measurements and lens designs. Unlike conventional RGPs, they need the eye’s several thousand points’ curvatures data obtained by a corneal topographer. All these curves are used to form multi-curved lenses, which conform more closely to cornea surface and create smoother point-to-point curvature changes. These measurements and lens designs provide more comfortable fitting for special eyes and also permit more oxygen to directly reach the eyes.

Custom contact lenses offer a change for everyone who has been disappointed by traditional RGPs. Custom RGPs are particularly useful for people with keratoconus and irregular corneal curvature, caused by eye injuries, failed LASIK or just born with that. Another type of custom RGPs are multifocal RGPs, which are created for presbyopia. In conclusion, custom RGPs provide a more effective way to correct myopia and astigmatism.

Soft contacts are also available in custom types, even if they are not as competitive as custom RGPs. But custom soft contacts do offer a better solution for high level astigmatism than conventional toric contacts, which are effective only for astigmatism below 2.5 diopters. Custom toric lenses offer higher powers as well as slighter increments.

Custom contact lenses may be your choice once you have failed in fitting some conventional contacts or you just want to make a change. Requiring additional time and skills, custom contacts cost about two times more than common contact lenses. You may contact your eye doctor for detailed information.

this article is come from:http://vision.firmoo.com/contact-lenses/contact-lenses-for-personalized-needs.html

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