Optical Training

Toric

A toric lens is a lens with different optical power and focal length in two orientations perpendicular to each other. ... Such a lens behaves like a combination of a spherical lens and a cylindrical lens. Toric lenses are used primarily in eyeglasses, contact lenses and intraocular lenses to correct astigmatism

Anti reflective coating

Aka AR level D

Bifocal

Bifocal prescriptions are for patients who have trouble seeing both near and far. Having two centers of vision. If you've got an eyeglass prescription for bifocal or multi-focal/progressives, your lens power corrects for near, far, and sometimes intermediate range vision. You'll have a number in the ADD column.

Hyperopia

Commonly known as farsightedness. Signs and symptoms: squinting, eye strain, headaches, squinting while reading things really closely Occurs when light rays entering the eye focus behind the retina rather than directly on it. Occurs when the eyeball is usually shorter than average. Fun note: sometimes children are born farsighted and outgrow it as the eyeball lengthens with normal growth. allaboutvision.com

Astigmatism

Etymology: "a" means without, "stigma" means point Correct way of stating: "You have astigmatism" NOT "You have an astigmatism" Astigmatism is a refractive error. There is just an error with how your eye focuses light. It's NOT a health problem or a disease. It's when light fails to come to a single focus point on the retina to produce clear vision. Instead of landing on a single focus point, light will land on multiple focus points either in front of, or behind the retina, or both. Symptoms: blurred or distorted vision at all or varying degrees. Squinting, eye strain, headaches especially after reading or other prolonged visual tasks. Causes: 1. an irregular shaped cornea (more common cause) aka corneal astigmatism. Instead of the cornea being round like a baseball, it is shaped more like a football that has one meridian that is significantly curved than the meridian perpendicular to it. 2. can be caused by the shape of the lens inside the eye aka lenticular astigmatism. Types of astigmatism: a) myopic astigmatism: one of both principal meridians of the eye are nearsighted. If both principal meridians are nearsighted, they are myopic in differing degree) b) hyperopic astigmatism: one or both principal meridians are farsighted (if both are farsighted, they're hyperopic in varying degree) c) mixed astigmatism: one principal meridian is nearsighted, and the other is farsighted. Note: Principal meridians definition: the steepest and fattest meridians of an eye with astigmatism. Regular vs. irregular astigmatism: >Regular astigmatism: the principal meridians are 90 degrees apart (perpendicular to each other) >Irregular astigmatism: can result from an eye injury that has caused scarring on the cornea from certain types of eye surgery or from keratoconus (disease that causes a gradual thinning of the cornea)

Single vision lens

If your vision correction is single vision, that means your lens power corrects for nearsighted or farsighted, but not both. The ADD column (which stands for additional magnifying in a multi-focal Rx) is blank Single Vision prescriptions are for patients who have trouble seeing either near or far (but not both).

AXIS

Indicates astigmatism. describes the degree and direction of your astigmatism.

ADD

It is added magnifying power in the lower part of a multi-focal lens. It's used to correct presbyopia which is the inability to focus on close objects.

OS

Left eye

Myopia

Nearsightedness, or myopia, is the most common refractive error of the eye, and it has become more prevalent in recent years. If you are nearsighted, you typically will have difficulty reading road signs and seeing distant objects clearly, but will be able to see well for close-up tasks such as reading and computer use. Other signs and symptoms of myopia include squinting, eye strain and headaches. Feeling fatigued when driving or playing sports also can be a symptom of uncorrected nearsightedness. Causes: Occurs when eyeball is too long relative to the cornea and lens of the eye. This causes light to focus at a point in front of the retina rather than directly on the surface of the retina. Occurs when the cornea and or lens is being too curved for the length of the eyeball. allaboutvision.com

Presbyopia

Normal loss of near focusing ability that occurs with age. (usually 30s or 40s) Even those who are nearsighted will notice their near vision blurs when wearing corrective lenses. Causes: 1.) it's age-related, N OT due to eyeball shape or genetics. 2.) believed to stem from a gradual thickening and loss of flexibility of the natural lens inside your eye. With less elasticity the eye has a harder time to focus up close >The age related changes occur within the proteins in the lens, making the lens harder and less elastic over time >a Unfortunately, even if those with presbyopia try to move things [their phone, menu, or books etc.] further away so they can see them, the object will get smaller in size. So holding your phone [or whatever object] a little further away than normal is only a temporary solution.

Spherical

Or aspheric With aspheric eyeglass lenses, thin is in. Advanced optical design technology allows aspheric eyeglass lenses to be made with flatter curves than conventional lenses, giving them a slimmer, more attractive profile. Most aspheric lenses also are high-index lenses. The combination of an aspheric design with high-index lens materials creates a lens that is noticeably slimmer, thinner and lighter than conventional glass or plastic lenses Aspheric lenses have a slimmer profile for virtually all prescriptions, but the difference is especially dramatic in lenses that correct high amounts of farsightedness. Lenses that correct farsightedness (convex or "plus" lenses) are thicker in the center and thinner at their edge. The stronger the prescription, the more the center of the lens bulges forward from the frame. Aspheric plus lenses can be made with much flatter curves, so there is less bulging of the lens from the frame. This gives the eyewear a slimmer, more flattering profile. It also makes it possible for someone with a strong prescription to wear a larger selection of frames without worry of the lenses being too thick. Eyeglass lenses that correct myopia (concave or "minus" lenses) have the opposite shape: they are thinnest at the center and thickest at the edge. Though the slimming effect of an aspheric design is less dramatic in minus lenses, it still provides a noticeable reduction in edge thickness compared with conventional lenses for myopia correction.

CYL

Or cylinder, indicates astigmatism, a condition where the cornea is irregularly shaped causing blurred or distorted vision. It also tells the lens strength needed to fix it.

Panoscopic tilt

Pantoscopic: The lens bottom is rotated towards the cheeks. Retroscopic: The lens bottom is rotated away from the cheeks. One of the easiest ways to understand pantoscopic tilt is to grab a pair of frames or a complete pair of eyeglasses. Once you have them, place them on a flat surface, temple tips touching the counter (sitting as though they are on someone's face). Next, look at them from the side. For example, turn the eyeglasses/frames so that if a person had them on, they would look to the right or left of you. This way, you will observe the eyewear from the side. From this vantage point, you will notice that the frames are not straight up and down looking at the eye wire, or rim. Instead, the eyeglasses are sitting at an angle, or tilt. Most of the time, all eyewear must sit on a patient with a certain amount of angle toward the face from the lower rim. This lower rim tilt toward the cheeks is called pantoscopic tilt, and it is needed in order for patients to rotate the eyes from distance to reading without having difficulty, looking under the glasses and in order to maintain vertex distance.

Photochromic

Photochromic lenses are optical lenses that darken on exposure to specific types of light of sufficient intensity, most commonly ultraviolet (UV) radiation. In the absence of activating light the lenses return to their clear state. Photochromic lenses may be made of glass, polycarbonate, or another plastic. They are principally used in eyeglasses that are dark in bright sunlight, but clear in low ambient light conditions. They darken significantly within about a minute of exposure to bright light, and take somewhat longer to clear. A range of clear and dark transmittances are available. Colors availble: green gray,gray, black, brown, blue Aka transition lenses

Soft contact lens

Soft lenses are made from gel-like, water-containing plastics called hydrogels. These lenses are very thin and pliable and conform to the front surface of the eye. Introduced in the early 1970s, hydrogel lenses made contact lens wear much more popular because they typically are immediately comfortable Silicone hydrogel lenses are an advanced type of soft contact lenses that are more porous than regular hydrogel lenses and allow even more oxygen to reach the cornea. Introduced in 2002, silicone hydrogel contact lenses are now the most popular lenses prescribed in the United States. When to replace SCL: Daily disposable lenses — Discard after a single day of wear Disposable lenses — Discard every two weeks, or sooner Frequent replacement lenses — Discard monthly or quarterly Traditional (reusable) lenses — Discard every six months or longer Soft contact lenses (both standard hydrogel and silicone hydrogel lenses) are available in a variety of designs, depending on their intended purpose: Spherical contact lenses have the same lens power throughout the entire optical part of the lens to correct myopia (nearsightedness) or hyperopia (farsightedness). Toric soft contact lenses have different powers in different meridians of the lens to correct astigmatism as well as nearsightedness or farsightedness. [Read more about toric contact lenses.] Multifocal contact lenses (including bifocal contacts) contain different power zones for near and far vision to correct presbyopia as well as nearsightedness or farsightedness. Some multifocal lenses also can correct astigmatism. [Read more about bifocal contacts.] Cosmetic contact lenses include color contacts designed to change or intensify your eye color. Halloween, theatrical and other special-effect contacts also are considered cosmetic lenses. A contact lens prescription is required for cosmetic contacts even if you have no refractive errors that need correction.

SPH

Sphere, spherical, aspheric indicates the eyeglass prescription power, or how strong your lenses need to be to correct your vision. For an indicator of how much magnifying power is needed in a bifocal or progressive lens to correct your vision problems, look for ADD.

Trifocal

Trifocals are eyeglasses with lenses that have three regions which correct for distance, intermediate (arm's length), and near vision. John Isaac Hawkins developed the trifocal lens in 1827.[1] Trifocals are mostly used by people with advanced presbyopia who have been prescribed 2 diopters or more of reading addition. The intermediate addition is normally half the reading addition. So, for someone with a distance prescription of −4 diopters and a reading addition of +3, the reading portion of their trifocals would have a net power of −1, and the intermediate segment would be −2.5 diopters. Trifocal lenses are made in similar styles to bifocals, but with an additional segment for intermediate vision above the reading section. A common style is the 7×28 flat-top or D-shaped segment, 28 mm wide, with a 7 mm high intermediate segment. Larger intermediate segments are available, and are particularly useful for people who spend a lot of time using computers. Trifocals are becoming rarer as more people choose to wear progressive lenses.

Progressive

Without any visible lines on the lens, progressive lenses offer a smooth transition from distance through intermediate vision to near vision. Progressive lenses also offer vision correction for all of the in-between vision zones. So instead of just having two or three different viewing zones, progressive lenses offer vision correction that progresses in power from the bottom to the top of the lens. This progression of correction eases eye strain by providing the most natural vision correction. Some people also call these no-line glasses or no-line bifocals. There are at least 4 different type of progressive lenses https://www.verywellhealth.com/progressive-lenses-3421915

Rigid gas permeable

Your eye doctor may call them GPs or RGPs. GP contacts are made of a firm, durable plastic that transmits oxygen. They offer excellent eye health: because they don't contain water like soft lenses do, they resist deposits and are less likely than soft contacts to harbor bacteria GP contact lenses are rigid, but they shouldn't be confused with old-fashioned hard contact lenses, which are now essentially obsolete. Hard contact lenses were made of a type of plastic called poly methyl methacrylate (PMMA). Before 1971, when soft contact lenses were introduced, just about all contact lenses were made from PMMA, which is also called acrylic or acrylic glass, as well being referred to by the trade names Plexiglas, Lucite, Perspex and others. Gas permeable contacts were first introduced in the late 1970s; they are actually a newer technology than soft lenses. Most GP lenses incorporate silicone, which makes them more flexible than PMMA. RGP lenses also provide better vision, durability, and deposit resistance than soft contact lenses. And because they last longer than soft lenses, they can be less expensive in the long term. So why doesn't everyone wear gas permeable lenses? Primarily because soft lenses are instantly comfortable, and GP lenses require an adaptation period before they are as comfortable as soft contacts. Gas permeable contacts are rigid lenses that float on a layer of tears and typically cover about 75 percent of the cornea. They're smaller than SCL https://www.allaboutvision.com/contacts/rgps.htm

OU

both eyes

Near variable focus lenses

near variable focus (or NVF). NVF lenses utilize all the latest optical design technology of progressives, but with the areas of the lens prioritized differently. NVF lenses offer a much wider intermediate-often three to four times that of a typical PAL-and they deliver the correct intermediate power at the fitting cross. This eliminates the need for patients to tip their head back to find the correct power. PAL stands for Progressive Addition Lens (seamless multifocal optical lens)

OD

right eye

Optics

the scientific study of sight and the behavior of light, or the properties of transmission and deflection of other forms of radiation. Optics is the branch of physics which involves the behaviour and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behaviour of visible, ultraviolet, and infrared light.