Thursday, December 29, 2011

Eye Injuries & Radiant Energy

Radiant energy such as ultraviolet radiation, X-rays and infrared radiation can cause eye injuries.

Ultraviolet Radiation
The most common radiation injury encountered results from the absorption of ultraviolet by the cornea. The ultraviolet of the sun is absorbed mainly by the atmosphere. With ultraviolet burns to the cornea there are no immediate symptoms but a few hours later the recipient's eyes begin to water and feel gritty. Later, as the symptoms progress, the foreign body sensation becomes extreme and the patient is in a great deal of pain. Tearing, congestion of the globe and marked photophobia (inability to tolerate light) occur. Staining of the cornea with fluorescein reveals slight pitting of its surface that is caused by erosion of the superficial epithelium.

Infrared Rays
The most common infrared calamity to the eye is an "eclipse burn" to the retina. This follows direct observation of a total eclipse of the sun. The effect of this injury to the retina is marked reduction in visual acuity that is permanent. Ordinary protective devices such as tinted glass, Polaroid lenses and usual filters are of no value in protecting against this hazard. Direct viewing of eclipses should be avoided.

X-rays are of very short wavelength, shorter than ultraviolet radiation and considerably shorter than the visible violet end of the spectrum. Exposure to x-rays can produce many ocular complications, including glaucoma, cataracts, necrosis of the skin, loss of lashes and Iritis. Consequently great care has been taken in the clinical use of x-rays exposure about the eye, to protect the patient from excessive dosage and the hospital staff from unnecessary exposure to dangerous radiation. As a result, the incident rate of eye complications among x-rays and radium workers is extremely low.

Please protect your eyes and your vision and should you be exposed to excessive ultraviolet, infrared or x-rays please do not hesitate to call Doctor & Associates at 203-227-4113.

Monday, December 26, 2011

History of Spectacles

You might be surprised to learn about the history of spectacles. No one knows when the earliest vision aids were used. There are no written recordings from early times. The ancients were aware of the optical effects of water or glass, e.g. the magnifying effect of a drop of water, the enlarged view of a leaf vein seen through a dew drop or the visual effect through a spherical transplant jewel of the underlying surface. Recent findings have shown that the Egyptians and Babylonians knew and utilized rules of optics. The oldest description of sunglasses was made by Pliny (23-79 B.C.). He wrote that the Roman emperor Nero used a polished emerald to view the gladiators. He does not mention if the optical surface was spherical but it is apparent that the light-absorbing nature of the gem made viewing in bright sunlight more pleasant. From the same era one can read complaints by older Roman statesmen that the condition of their eye made reading of legal texts difficult. It is sure that presbyopia was considered a disease in ancient Rome but no one documented any treatment with usual aids. The earliest mention of a visual aid was the reading stone. The stone was a polished hemisphere of the semi-precious gemstone beryl which, when laid on a page, enlarged the text in all directions.

The inventor of spectacles, meaning glasses worn directly on the eye, is unknown.

Classic spectacles that are worn directly over the eyes appeared in more recent times when clear, transparent glass became available at a reasonable price. The first occurred on Murano, a small island near Venice still famous for the production of glass. Developments from spectacle manufacturers no longer required that the lens be placed on the text in order to read; it could now be held in front of the eye.

There were minor improvements made during making: better lens polishing, new methods of stabilizing the positioning of spectacles for reading and some improvements in lens coating. The 16th and 17th centuries saw the appearance of lens expensive spectacles, usually +3D intended for presbyopia (reading), that were framed in leather or iron. Products with horn and copper frames were made for the clergy or public officials while those frames in gold, silver or ivory were rarities reserved for the very wealthy.

It is amazing that the use of curved earpieces is only 100 years old. The history of spectacles is the history of scientific progress. Spectacles have enabled millions of people with visual problems to take part in daily life and to acquire an education. From their beginning as a reading lens made of the gemstone beryl, glasses have improved to include multifocal lenses, contact lenses and implants into the living eye. 

If you have questions about spectacles or eyewear please feel free to ask us at Doctor & Associates-203-227-4113.

Thursday, December 22, 2011

What are Prisms?

We sometimes use prisms in both your eye exam as well as in your eyeglass prescription. A prism is a triangular, or wedge-shaped, piece of plastic or glass that has the property of displacing a bundle of light toward the base of the prism. A prism has flat sides, an apex, and a base. If the prism is placed before the eye, an object viewed in front of the prism will appear to be displaced toward its apex. Prisms are employed in measuring the presence of the amount of any tropias (an obvious misalignment of the eyes) or phorias (a tendency toward ocular misalignment that is held in check by the fusion effort of the extra ocular muscles). 

Types of prisms that are available are loose prisms, horizontal and vertical prism bars and Risley's rotary prism. The loose or individual prism is made of plastic or glass. These prisms are supplied in low powers in standard trial lens sets and in full range of powers in individual prism boxes.

Horizontal and vertical prism bars are fused prisms amalgamated into a single bar of gradually increasing strengths. These prisms may be set in a horizontal direction (base in or out) or in a vertical direction (base up or down). The prism bar is principally employed to measure the amplitude or power of fusion.

Risley's rotary prism consists of two counter-rotating prisms mounted in rings, one in front of the other. These rings are easily rotated in opposite directions by a small thumbscrew. Risley's rotating prism provides a rapid and simple increase in prism power strength so that a deviation may be rapidly adjusted and measured without the delay in introducing individual prisms before the eye.

If you have questions about eye exams and how we use prisms please feel free to contact us at Doctor & Associates-203-22-4113.

Tuesday, December 20, 2011

Prevention of Eye Injury in Industry

Prevention of eye injury in industry settings is an important consideration for many people. The use of safety glasses has been of greatest importance inasmuch as the glass itself becomes a protective shield for the eye. Although ordinary glasses for street wear and industrial glasses may look alike, the similarity ends there. The difference between the two of lenses and frames is vast.  Regular street glasses, for example, can shatter easily into the eye. In contrast, industrial safety lenses are thicker and hardened so that they resist, without shattering. The best safety glasses are made of polycarbonate plastic. The frames of safety glasses also are of different construction. In addition to being flame resistant, they are designed to retain the safety lenses under heavy impact.

Contact lens wear may be hazardous in the fume-and chemical-laden environments of some industries. They must wear protective goggles as well as protection against flying missiles.

Industrial safety lenses should be employed when work or hobbies are pursued that involve lathing, chiseling, grinding or hammering. The hazard to the eye is even greater than in industry, because home lighting conditions are not always optimal and built-in safely guards are now always found in home machinery.

If you are interested in purchasing safety glasses Willows eyewear will be happy to help. Please call 203-227-9380 with any questions.

Thursday, December 15, 2011

Scratched Cornea & Corneal Abrasions

Corneal abrasions are superficial scratches and erosions of the cornea. They are found after corneal foreign bodies have been removed, either spontaneously or with treatment. They are most commonly found after injuries caused by paper, fingernails, wires and so forth. A corneal abrasion, unless it is large, cannot be seen with the naked eye. Patients with a corneal abrasion complain of a foreign body sensation of the eye. Often these patients are seen by a nurse or a friend and told that there is nothing in their eye and as a result they suffer until they are finally seen by the ophthalmologist; any person who complaints about a foreign body sensation of the eye should be seen. Fluorescein strips should be placed in the eye to stain the area of the corneal defect and the eye should be examined with magnifying glasses. Corneal abrasions are treated by firm patching for 24 hours; the larger the abrasion, the longer the time to heal. The bandage soft contact lens may minimize the pain. Usually corneal abrasions are very uncomfortable with the eye tearing and difficulty to keep the eye open. It is important to address the issue as soon as possible.

Protect your eyes and be careful while working outdoors. If you have any questions regarding scratched cornea or corneal abrasions please schedule an appointment for an examination at Doctor & Associates by calling 203-227-4113.

Tuesday, December 13, 2011

What is Anti-Reflective AR Coating?

An anti-reflective coating (also known as AR coating or anti-glare coating) improves both your vision through your lenses and the appearance of your eyeglasses. Both benefits are due to the AR's ability to eliminate reflections of light from the front and back surface of eyeglass lenses. AR coating is especially beneficial when used on high index lenses, which reflect more light than regular plastic lenses. Generally, the higher the index of refraction of the lens material, the more light that will be reflected from the surface of the lenses.

For example, regular plastic lenses reflect roughly 8% of the light hitting the lenses, so only 92% of available light enters the eye for vision. High index lenses can reflect up to 12% allowing only 88% of available light to the eye for vision. This can be particularly troublesome in low light conditions, such as night driving. Today’s modern anti-reflective coating can virtually eliminate the reflection of light from eyeglass lenses allowing 99.5% of available light to pass through the lenses and enter the eye for good vision.  By eliminating reflections, AR coatings also make your eyeglass lenses look nearly invisible so people can see your eyes more clearly. Anti-reflective coatings also make you glasses look more attractive so you can look your best in all lighting conditions.

Unlike the older generation of AR coatings, today’s premium coatings include a “hydrophobic" and "oleophobic" surface. These surfaces repel water and skin oils which make the surface much easier to keep clean.

If you have any questions or are interest in having AR coating our Opticians at Eyewear at Willows will be happy to help. Please call them at 203-227-9380.

Friday, December 9, 2011

What is Refraction?

Refractometry is defined as the measurement of refractive error and it should not be confused with the term refraction. Refraction is defined as the sum of steps performed in arriving at a decision as to what lens or lenses (if any) will most benefit the patient. These steps include, in addition to Refractometry, measurements of visual acuity, measurement of accommodative ability and the exercise of clinical judgment. Refractometry, on the other hand, is strictly limited to clinical application of optical principles. This measurement function can be performed at the highest level of precision by technicians and, in some cases, even by sophisticated instruments and computers.

The exercise of clinical judgment included in the foregoing definition of refraction refers to a consideration of such factors as the patient's occupational requirements, muscle balance, impairment of vision by other than refractive error (such as cataract, macular degeneration or amblyopia), the extent and type of refractive error present and even the emotional "set" of the patient with respect to wearing glasses. For some patients, even though there may be a significant error, the maximum benefit will be achieved by prescribing no lenses at all.

If you have any questions regarding refraction or measurement of refractive error please schedule an appointment for an examination at Doctor & Associates by calling 203-227-4113.

Tuesday, December 6, 2011

Types of Ophthalmic Eyeglass Lenses

The many types of ophthalmic eyeglass lenses can sometime be confusing. Too often, eyeglass wearers do not spend enough time selecting their lenses. Most do not realize that all eyeglasses are different. Your eye care professional can tell you about the variety of materials, coatings, styles and thicknesses of lenses available to help make your glasses look and perform their very best. As for the different types of lenses, these can be divided into four main categories; single vision lenses, bifocal lenses, progressive lenses and occupational lenses.

Single vision lenses have the same focal power throughout the entire lens and can be used to correct myopia, hyperopia, and astigmatism. Single vision lenses are usually used by eyeglass wearers under the age of 40.

Bifocal lenses used to be the only option for people with presbyopia who also require a correction for myopia, hyperopia and/or astigmatism. They are lenses that carry two distinct optical powers in each lens. As that is an old technology, progressive lenses are now the new option for better aesthetics and comfort.

Progressive lenses are also designed to counter presbyopia. They correct the effects of presbyopia with a gradual change of power from near to distance vision, restoring natural vision without the unsightly segmentation lines or image jump experienced with standard bifocals. Progressive lenses offer comfortable vision at all distances.

Some lenses are specially designed for specific functions, as opposed to regular, everyday use. For example, keeping pace with the computer use where reading lenses for both near and intermediate vision are being used.

Nowadays we can offer better quality of lenses. Digital lenses are available for patients who were not successful with progressive lenses in the past. Good candidates are people with high prescriptions and a lot of astigmatism. Digital lenses require extra measurements from the optician to make progressive glasses prescription more accurate and better fit for the person's needs.

If you have any questions about lenses or interested in trying digital lenses please call Eyewear at Willows at 203-227-9380.

Thursday, December 1, 2011

Crossed Eyes or Strabismus

Crossed Eyes are called Strabismus. Strabismus is a misalignment of the eyes that may cause vision to be disturbed and results from the extra ocular muscles of the eye not working in a coordinated manner.

One of the first things we address in treating Strabismus is the elimination of any coexisting Amblyopia which is often referred to as “Lazy Eye.” Some forms of Strabismus can be corrected by improving the vision in the Amblyopic eye inasmuch as the eye muscle control may improve at the same time. In addition, the eyes may straighten in some patients with Strabismus who require glasses to correct vision or Amblyopia.

An eye condition in which the direction that the eyes are pointing is not consistent with each other is called heterophoria. Patients with well-controlled heterophorias may need no treatment at all. Some forms of Strabismus, such as nerve palsies, are temporary and will resolve with time. Other forms, such as convergence problems that cause reading difficulties, will respond to exercises. Sometimes patients who have double vision may experience relief of the double vision and regain fusion and single vision through the use of prisms. Both permanent and temporary types of prisms are available to help patients.

If none of these treatments is indicated or is successful in straightening the eyes, then two options are available. One is eye muscle surgery, which involves the strengthening of weak eye muscle and weakening of overactive or tight muscle. The other option is the injection of Botulinum toxin into the eye muscle, which paralyzes them and straightens the eyes with certain forms of strabismus.

If you have any questions regarding Crossed Eyes or Strabismus or Lazy Eye or Amblyopia please schedule an appointment for an examination at Doctor & Associates by calling 203-227-4113.