Far sighted

  Near sighted

  Astigmatism

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Light rays focus behind the retina (back of the eye like the film in a camera)

Light rays focus in front of the retina

Some light rays focus in front of the retina and some behind.

  REMEDY

 

 

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The eye can focus the lens to remedy small and equal amounts

Near objects can be seen well, all distance objects are blurred. Squinting helps distance vision some.

The blur is always present.

  TREATMENT

 

 

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plus lens

minus lens

cylinder lens

 

 

 Eye protection guide\ Drivers

I've read there are documented cases of airbags deploying and breaking the drivers eyeglass lenses. Polycarbonate lenses are the strongest and safest optical lenses especially if you are smaller in stature or sit close to the steering wheel.

Sports: every 13 minutes a person with a sports related eye injury visits an emergency room so if your favorite sport involves any kind of "ball" ,an object which soars through the air, or involves velocity; Polycarbonate lenses are the strongest and safest optical lenses. Recommended eye protection for:

Baseball - ASTM standard F910 faceguard attached to the helmet

Basketball, Field hockey, soccer, Volleyball - ASTM standard F803

Football - Polycarbonate eye shield attached to helmet

If you answer yes to any of the following it is recommended that your eyewear always contain polycarbonate lenses.

Suffered previous eye injury____        Have ocular implants_____        Vision in only 1 eye____

Eye disease_____        Over 65 years of age____

*ASTM is an abbreviation for American Society for Testing and Materials

 

If you have any questions regarding your prescription, type of lenses, or lens materials please contact our office at 708-686-5266.

Lens types: Single vision Bifocal Progressive Lenses Trifocal Occupational

Single vision lenses correct for only one purpose. To see clearly and sharply at a distance or to read up close.

Bifocal lenses are designed with two focal points: the top portion of the lens provides clear sharp vision at a distance (approximately past your armís reach) and the bifocal region which is shown with a line allows you to read at a distance range of 16 -21 inches.

Progressive lenses have the unique capability to provide you with clear sharp vision at a distance, a mid range, and read up close. There are over 50 different varieties of progressive lenses. And it is very important your eye care provider know exactly what type of mid range and close work activities your eyes are engaged with. Progressive lenses are very sensitive to the distances you work at and higher prescription strengths.

                                                                                   

Trifocal lenses are designed with three focal points: the top portion of the lens provides clear sharp vision at a distance (approximately past your armís reach), the middle portion is designed for distances between 22 - 28 inches and the bifocal region allows you to read at a distance range of 16 -21 inches. This type of bifocal is characterized with two lines and is very sensitive to the distances you work at and higher prescription strengths.

Occupational lenses come in a variety of designs. For example one type of occupational lens has a bifocal region on both the top and bottom portion of the lens. Three types of progressive lenses are available for computer users; even those who donít regularly wear glasses of any kind.


Lens materials: Glass CR 39 Plastic Polycarbonate High Index Trivex

Glass is the oldest material to make eyeglasses. On the plus side glass doesnít scratch as easily and is available in a variety of standard tints. This lens material is ideal for welding for the surface doesnít burn and employees who grind find it is more resilient to scratches. On the negative side the lenses are very heavy. Also glass lenses with a photosensitive tint stay darker and darker indoors as they age thus interfering with clear sharp vision indoors and nighttime driving. Some progressive lenses are not made in glass.

CR 39 plastic provides optical qualities similar to glass. On the plus side CR 39 plastic is light weight, easily tinted in a wide range of colors including Transitions, and most progressive bifocals are available. Unlike polycarbonate; CR 39 is not adversely effected by harsh chemicals On the negative side CR 39 plastic is easily scratched and tints can fade.

Polycarbonate is light weight, has a built in UV filter, and automatically is made with a grey tint. On the plus side polycarbonate has a higher safety factor than glass or CR 39 plastic. Polycarbonate lenses can be tinted in a limited range of tints and is available in Transitions. Most progressive bifocals are available in polycarbonate. On the negative side polycarbonate lenses cannot be used in certain industrial environments as they can be permanently fogged by certain chemicals. Polycarbonate lenses are stronger than CR 39 plastic when it comes to scratching but can be scratched.

High Index is the solution for individuals with very high prescriptions to limit both the weight and thickness of the lenses. High index has all the features of polycarbonate. On the negative side High index lenses require a period of adjustment to the prescription as it can alter images due to its Index of Refraction.

Trivex is the latest technological advancement in lens materials. Similar to polycarbonate;  on the plus side this lens, when approved, will be available in 2.0 mm. thickness versus the current OSHA standard of 3.0 mm. This can greatly improve the comfort of safety glasses by reducing the weight factor. Trivex is not currently available in all prescriptions and bifocal types.

 

 

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