Contacts and Eyeglasses are prescription medical devices that are worn on or over the eye. In order to prescribe any lenses an eye doctor must evaluate the health of the eye, determine the proper lens prescription based on each individual patient’s different glasses prescription, vision needs, corneal health and curvature and examine the lens on the eye to ensure proper alignment with the cornea. A lens evaluation is a separate part of a comprehensive eye examination and requires additional testing that people who do not wear lenses do not need to have. Lens examinations and fittings have different levels of difficulty, this depends on the types of contact needed, the visual requirements of the patient and the health of the patient’s eyes.
Contact Lens Evaluation
- Check corneal integrity
- Convert a spectacle prescription into a contact lens diagnostic presciption
- Measure the corneal curvature
- Provide a diagnostic contact lens for evaluation (disposable soft contacts only)
- Training of insertion, removal, and storage of contact lenses (new wearers or retraining)
- Check the visual acuity with contact lenses
- Check for proper fit of contact lenses on the cornea
- Check for tears, rips, holes, deposits on contact lenses
- Provide sample solution / starter kit
- Provide written Contact Lens Prescription(Expires in 1 year)
- Provide follow up visit up to 3 months from contact lens evaluation date
Lens Options for Eyeglasses
When it comes to choosing options for your eyeglasses, there are quite a few options that best suites your lifestyle and visual needs.
High index lens 1.67 and 1.74 material: Thinnest and lightest
High index lenses can be up to 50% thinner than regular standard plastic lenses and much lighter too. They are generally recommended for higher prescriptions to decrease the weight of the lenses in eyeglass frames and cosmetically look better too! Most people with high prescriptions would like to avoid a “bottle eye” look when it comes down to their lenses.
High index lenses comes in various price points due to the technology and difficulty of manuafacturing them. Typically the thinner the lens, the higher the price point in comparison the the basic and traditionaly standard plastic lens.
Generally, lenses with a higher index of refraction will be thinner (and usually more expensive) than lenses with a lower index. The index of refraction of regular plastic lenses is 1.50. The refractive index of high index plastic lenses ranges from 1.60, 1.67, 1.71, and 1.74. Those in the range of 1.60 are about 20% thinner than regular plastic lenses, whereas 1.74 high index lenses are about half the thickness of regular plastic lenses.
Most popular lens designs (single vision, bifocal, progressive, photochromic, etc.) come in high-index materials, and your doctor or optician will know which ones are available in your prescription. Bifocal and trifocal high index lenses are also available, though the selection is more limited.
High index lenses reflect more light than regular plastic lenses, therefore anti-reflective coating is highly recommended for these lenses.
Polycarbonate lenses: Strong, Safe, Lighter, Thinner with a built in Sractch resistance and UV coating.
Polycarbonate lenses offer superior impact resistance. These lenses are up to 10 times more impact resistant than regular plastic lenses, making them an ideal choice for children’s eyewear, safety glasses, monocular patients, firefighters, policeman, and for anyone with an active lifestyle who wants a thinner, lighter, safer lens.
Polycarbonate lenses have a refractive index of 1.59, making them approximately 25 to 30% thinner than regular plastic lenses. They are also up to 30% lighter than regular plastic lenses, making them a good choice for anyone with a high prescription, better cosmetically looking lens, half rim, and rimless frames.
Anti-Reflective/Anti-glare coating: Less reflection, cosmetically more appealing, less eyestrain, optically clearer.
All eyeglass lenses reflect some light, reducing the amount of light that enters the eye. This can have an impact on vision, especially under low-light conditions, like when driving at night. It also impacts your vision especially in front of a computer screen. The glare from light sources can also cause eye fatigue.
Lens can come with glare or without glare. Standard plastic lenses have glare from light sources and approximately 89% of the light that travels through the lens makes it directly into the eye. Lens coating with the anti-reflective coating reduces glare and therefore allows approximately 99% of the light to travel into the eyes. This helps with optical clarity, reduced eyestrain and fatigue, and helps others see your eyes more clearly without reflection.
Night time vision is also improved with an anti-reflection coating.
By eliminating surface reflections, anti-reflective coating also makes your lenses nearly invisible. This greatly improves the appearance of your eyewear and allows others to see your eyes, not the reflections in your glasses.
When cleaning lenses with anti-reflective coating, use only productst that are safe for anti-reflective treated lenses. Mild soap and warm water can sometimes be used to clean a AR coated lens. Never use an amonia product such as windex and the chemical is very harsh on the coated lens and can cause the AR coating to degrade and crack. AR coated lenses also tends to attract more smudge, be sure to use a cleaning cloth designed for eyeglass lenses and try not to use any abrasive materials that can scratch the AR coating.
Scratch Resistant Coating
No eyeglasses material is scratch proof, however, having scratch resistance coating can help prolong the life of the lens my minimizing normal wear and tear scratching. Whether it’s from dropping your glasses on the floor or occasionally cleaning them with a paper towel. Kids’ lenses, especially, benefit from a scratch-resistant hard coat.
Nearly all high index lenses and polycarbonate come with a factory-applied scratch-resistant coating for added durability. This coating is optional for regular plastic lenses. However, to safeguard your investment in your eyewear, scratch-resistant coating should be considered for all eyeglass lenses. The only exception is glass lenses, which are naturally hard and scratch-resistant.
To further protect your eyeglasses from scratches, keep your glasses in a protective case when you’re not wearing them. Also, never clean your lenses without first rinsing them with a cleaning solution or water. Do not use any amonia products such as windex on your lenses. Rubbing a dry, dusty or dirty lens with a cleaning cloth or towel can cause scratches, even on lenses with a scratch-resistant coating.
Ultraviolet (UV) coating
Just as you use sunscreen to keep the sun’s UV rays from harming your skin, UV treatment in eyeglass lenses blocks those same rays from damaging your eyes. Overexposure to ultraviolet light is thought to be a cause of cataracts, pingueculas, pterygiums, macular degeneration and other eye problems.
Most high index lenses have 100% UV protection built-in. But with regular plastic lenses, a lens treatment is required for these lenses to block all UV rays. This UV treatment does not change the appearance of the lenses and is quite inexpensive.
Photochromic lenses: Changes color in direct sun light. Sun and clear lenses: Two in One.
Photochromic lenses are convenient indoor-outdoor eyeglass lenses that automatically darken to a sunglass shade outside when exposed to sunlight, and then return to a clear state indoors. Photochromic lenses darkens in seconds in direct sunlight or when exposed to UV light. These lenses clears up in a few minutes when going indoors. Photochromic lenses are convenient because it’s like having sunglasses and clear glasses “two in one”. Don’t forget that photochromic lenses do not darken will in the car because a car’s windshield and windows block off UV light need to activate the particle in the lenses to darken. These lenses also provide 100% protection from the sun’s UV rays, and are available in a wide variety of lens materials and designs, including bifocal and progressive lenses.
We’re here to help!
With many lens options available, it’s hard to know all your options and decide which lenses are best for you. We are here to educate you on the the options that may best suite your vision and lifestyle needs.