Factors in Determining Lens Glasses Thickness
Glasses historically had very thick lenses, but over time, the average thickness of the lens glasses has been significantly reduced. There are multiple factors which contribute to the thickness of lenses including the material of the lens, the amount and type of prescription, the fit of the frame on the face, and the size of the lenses. Considering these factors is important when purchasing glasses to ensure the lenses are as thin as possible for the best appearance.
Why Thick Lenses are Avoided
The thicker the lenses in glasses, the more likely it is that the glasses will be heavy or bulky, the glasses will be more likely to change the size of the eyes when viewed, and the glasses may appear less appealing.
The weight of the lenses is the primary contributor to the overall weight of the glasses.
The thinner the lenses, the more likely the glasses will be lightweight and comfortable on the face
Thicker lenses also will change the size of the eyes when viewed from outside. Thick lenses may cause the eyes to appear magnified or minified and abnormal compared to the rest of the face.
Another concern with thick lenses is that they may appear less appealing. Thicker lenses may have a Coke bottle effect on the glasses.
Lens Material for Thickness
The biggest factor for changing the thickness of lenses is changing the lens material.
The index of refraction is a property of a lens material that determines how much light it can bend through the lens.
The higher the index of refraction, the more light will be bent.
So, when considering lens thickness, the higher the index of refraction, the thinner the lens will be.
Thickness by Prescription Type
A high prescription will have a thicker lens than a lower prescription if all factors are equal.
Prescriptions over four diopters May have to have changes made to prevent the lenses from being too thick.
High prescription lenses are best to use a high index of refraction material to keep the lens as thin as possible.
Additionally, if the lens is a plus powered lens for farsightedness, it will be thicker than a minus powered lens for nearsightedness due to the shape of the lens.
Plus powered lenses will be thickest in the middle of the lens, while minus power lenses are thickest on the edge.
Fit of the Frame for Lens Glasses Thickness
If a frame does not fit well on the face, the lens may have to be unnecessarily thicker.
The frame should match the distance between the eyes and allow the lenses to be centered in the frame.
If the frame is too large or too small, the lenses will be decentered to provide clear vision but may be thicker due to the change in positioning.
Similarly, large frame sizes will have thicker lenses because more of the lens is included in the frame. Smaller lens sizes can allow thinner lenses to be used in the frame.
Our eye doctors at GHEye excel in the prescription of glasses, contact lenses and the diagnosis of a variety of eye diseases. Call our optometrists at (571) 445-3692 to schedule your appointment today to be evaluated for lens glasses thickness. Our eye doctors, Dr. Ally Stoeger and Dr. Jennifer Sun, provide the highest quality optometry services and eye exams in the Gainesville VA and Haymarket VA areas.
Glasses historically had very thick lenses, but over time, the average thickness of the lens glasses has been significantly reduced. There are multiple factors which contribute to the thickness of lenses including the material of the lens, the amount and type of prescription, the fit of the frame on the face, and the size of the lenses. Considering these factors is important when purchasing glasses to ensure the lenses are as thin as possible for the best appearance.
Why Thick Lenses are Avoided
The thicker the lenses in glasses, the more likely it is that the glasses will be heavy or bulky, the glasses will be more likely to change the size of the eyes when viewed, and the glasses may appear less appealing.
The weight of the lenses is the primary contributor to the overall weight of the glasses.
The thinner the lenses, the more likely the glasses will be lightweight and comfortable on the face
Thicker lenses also will change the size of the eyes when viewed from outside. Thick lenses may cause the eyes to appear magnified or minified and abnormal compared to the rest of the face.
Another concern with thick lenses is that they may appear less appealing. Thicker lenses may have a Coke bottle effect on the glasses.
Lens Material for Thickness
The biggest factor for changing the thickness of lenses is changing the lens material.
The index of refraction is a property of a lens material that determines how much light it can bend through the lens.
The higher the index of refraction, the more light will be bent.
So, when considering lens thickness, the higher the index of refraction, the thinner the lens will be.
Thickness by Prescription Type
A high prescription will have a thicker lens than a lower prescription if all factors are equal.
Prescriptions over four diopters May have to have changes made to prevent the lenses from being too thick.
High prescription lenses are best to use a high index of refraction material to keep the lens as thin as possible.
Additionally, if the lens is a plus powered lens for farsightedness, it will be thicker than a minus powered lens for nearsightedness due to the shape of the lens.
Plus powered lenses will be thickest in the middle of the lens, while minus power lenses are thickest on the edge.
Fit of the Frame for Lens Glasses Thickness
If a frame does not fit well on the face, the lens may have to be unnecessarily thicker.
The frame should match the distance between the eyes and allow the lenses to be centered in the frame.
If the frame is too large or too small, the lenses will be decentered to provide clear vision but may be thicker due to the change in positioning.
Similarly, large frame sizes will have thicker lenses because more of the lens is included in the frame. Smaller lens sizes can allow thinner lenses to be used in the frame.