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If you’ve ever tried researching an eye disease or attempted to understand your latest eyeglass prescription, you might quickly find yourself confused with all the different words used in the eyecare industry. To make things easier, we put together a list of the most popular eyecare buzzwords and their meanings.
Add - On an eyeglass prescription, these numbers refer to additional (magnifying) power needed to correct vision up close.
Age-Related Macular Degeneration – Also known as AMD, occurs when the central portion of the retina (known as the macula) deteriorates, leading to a loss of central and detailed vision.
Anti-Reflective Coating – Sometimes called AR or no-glare, this coating on eyeglass lenses eliminates reflection of light from the front and back side of the lens.
Astigmatism – A vision condition that causes blurred vision. Astigmatism comes from either an irregular shaped cornea or sometimes the curvature of the lens inside the eye.
Axis – On an eyeglass prescription, this number describes the position of the astigmatism in the eye.
Bifocal Lens – This lens is made of two parts – the top of the lens is made for seeing things at a distance, while the bottom part of the lens is made for reading and viewing things close up.
Blue Light – Part of the visible light spectrum emitted by the sun and artificial light sources such as LEDs, computers, some smart phones, and tablets. Some blue light is beneficial and aids in the function of the sleep/wake cycle, memory, and cognitive performance; but there is a specific band of blue light that is found to have a harmful effect on the retina and is a risk factor for the onset of age-related macular degeneration (AMD).
Cataracts – A buildup of protein on the lens of the eye that can lead to blindness.
Conjunctivitis – Often referred to as pink eye, it is an inflammation of the clear membranes covering the white part of the eye, lining the inside of the eyelid, otherwise known as the conjunctiva.
Cornea – The clear layer at the front of the eye.
Cylinder – On an eyeglass prescription, this number refers to the amount of astigmatism in the eyes.
Detached Retina – A serious condition where the retina separates from the tissue around it, keeping the retina from functioning properly.
E-SPF® – The eye-sun protection factor is an international index certifying the overall UV protection provided by a lens, meaning the higher the rating, the higher the UV protection to the eyes. For example, E-SPF 25 means the eyes are 25 times better protected than they are without lenses. The index ranges from zero to 25 for clear corrective lenses and from zero to 50 for sunglass lenses.
Floater - Tiny gray spots in the eyes that seem to weave in and out of the person’s line of vision. Floaters are generally benign or harmless.
OD – This term is used on eyeglass prescriptions and is the Latin abbreviation for oculus dextrus, meaning right eye. OD can also stand for doctor of optometry. This is the degree an optometrist receives after completing four years of optometry school preceded by three years (or more) of college.
Ophthalmologists - According to the American Academy of Ophthalmology, ophthalmologists are medical or osteopathic doctors (DO) that are licensed to practice medicine and surgery.
Ophthalmologists diagnose and treat all eye diseases and perform eye surgery. They also may be involved in scientific research on the causes and cures for eye diseases and vision disorders.
Opticians - Opticians use the prescriptions written by optometrists and ophthalmologists to provide you with the right kind of eyeglasses and contact lenses. Opticians also measure and adjust your eyeglasses so they’ll fit properly.
Optometrists - According to the American Optometric Association, optometrists (also referred to as Doctors of Optometry or OD) are the independent primary healthcare professionals for the eye. Optometrists examine, diagnose and treat the eyes and visual system as well as manage diseases, injuries, and disorders of the eye and associated structures. They are also able to identify related conditions affecting the eye. The laws defining scope of practice for optometry are determined on a state by state basis.
OS – This term is used on eyeglass prescriptions and is the Latin abbreviation for oculus sinister, meaning left eye.
Polarized lens – A type of sunglasses lens that most effectively reduces glare by blocking intense reflected light, while providing exceptional color perception and contrast.
Polycarbonate – A lens material that is up to 10 times more impact resistant than plastic or glass lenses. Polycarbonate lenses are also lightweight and provide 100% protection from the sun’s harmful UV rays.
Presbyopia – An eye disorder that naturally happens due to decreased flexibility of the lens. Presbyopia happens around the age of 40 and causes blurred vision when looking at objects up close.
Pupillary Distance – Sometimes called PD, it is the distance between the centers of each pupil.
Single Vision Lens – This lens offers the same amount of vision correction over the entire area of the lens.
Sphere – This term is used on eyeglass prescriptions to indicate the amount of lens power prescribed to correct nearsightedness or farsightedness.
Trifocal Lens – This lens with visible division lines offers correction for near and far vision, but also enables a person to see clearly at an intermediate level (about arms length).