Axis

The axis is the number on the prescription that determines the direction of the astigmatism correction. It’s measured in degrees and determines the exact place where the lens correcting the astigmatism should be. Cylinder and axis always come together – if your optometrist measured your cylinders, you will see a number corresponding to the axis on your prescription.

Acetate

Acetate, or more technically "cellulose acetate”, is the diamond of plastics. It’s highly durable and hypoallergenic and yet it can be made highly colorful which makes it an ideal material for making glasses. Acetate softens when heat is applied which means it can be molded and the frame can be adjusted to fit the owner exactly, without any fear of the material breaking

Anisocoria

About 20% of people have a slight difference in pupil size. This is known as anisocoria and it doesn’t need to be an indication of an illness. If it appears suddenly, however, it could be an urgent problem and we recommend you visit a specialist straight away.

Amblyopia

This disorder of sight, also called lazy eye, is usually found in children. It arises when an anomaly in the development of the nerve pathway between brain and eye results in one of the eyes “failing to learn” to see properly.

Anti-reflective coating

An anti-reflective coating is a very important lens coating that stops light reflecting from the lens. It helps the wearer to see more sharply without straining the eye excessively. Eyes look more natural with this coating because reflections are reduced.

Astigmatism

Astigmatism is a very common optical condition which results in blurry or misty vision. When uncorrected, this condition often causes headaches and hair loss. It arises when an irregular curvature of the cornea’s shape prevents light from reflecting properly on the back of the eyes and thus causes problems with sharpness of vision. The good news: glasses compensate well for astigmatism if worn daily.

Autorefractor

A machine which helps determine the right level of vision correction. It works by shining a light straight into the eye and then measuring changes in the light that gets reflected back into the machine. This way optometrists are provided with ultra-accurate data which they can use to correct vision.

Asthenopia (eyestrain)

You know how New Year’s resolutions work. You decide it’s time to slim down, you go to a gym, you do your best -- and then you can’t get out of bed the next day. The same thing happens to your eyes when they are used intensely. Whether you’ve been staring into a computer screen for too long, or driving at night, your eyes need some rest from time to time. If asthenopia persists, we recommend getting your eyes checked. It’s highly likely you might get a chance to buy some pretty glasses.

Arm/temple

The arm, also known as the temple, is one of the side bits of your frames. Glasses always have two arms – the right one and the left one. Arms hold the glasses on the person’s face and they should fit the person wearing them perfectly, especially behind their ears.



Blink reflex

Our eyes are very fragile and irreplaceable little organs and we need to protect them accordingly. Basic protection is provided by the eyelids and the blink reflex. These ensure that our eyes close instantly when a threat is detected. On average people blink every 3 seconds. Blinking helps to keep our eyes moist and our tears help flush out all sorts of bacteria and foreign particles. If we forget to blink (this often happens when looking at a screen), our eyes might get dry which makes them burn. This might make us feel we need glasses. The dry eyes can be helped with “fake tears” – eye drops that we add instead of tears.

Bridge

The small bit of the frame that holds the glasses on top of your nose bridge. Remember that your glasses always have to fit perfectly and the bridge is key to that. Some glasses have nose pads that help the glasses to fit the wearer’s nose better.



Cylinder

This can be found on your prescription given to you by an optometrist or ophthalmologist. It defines the lens power needed to correct astigmatism.

Color blindness

People with color blindness see colors in a different way to most people. It’s a reasonably common disorder and can affect people to different degrees. Many people with color blindness might not even be aware of it. It’s usually a genetic condition, which means you are born color blind. Genetic color blindness is carried through the X chromosome which means that more men than women are affected. It’s estimated that about 0.5% of women and 8% of men suffer from some form of color blindness.



Dilatation

Dilatation is a process in which the ophthalmologist uses special eye drops to dilate the pupils to examine the retina with greater accuracy. An unpleasant side effect of dilatation is worsened, blurry vision and higher sensitivity to light that can last for a few hours. If you know you’re going to go through this process, we recommended that you bring sunglasses to the appointment and make sure you don’t drive for the rest of the day.

Diopter

Diopter is a unit of measurement of optical power. It’s a unit of measurement just like a gram or a meter. It is equal to the reciprocal of the focal length in the eye. It measures the refractive power of the lens



Eye drops

Different liquids applied to your eyes for various reasons. It takes practice because applying eye drops doesn’t feel natural for the eyes. There are all sorts of eye drops that help with different kinds of problems: dry eyes, itching and burning as well as eye infections and inflammations. You should always consult your doctor before using any kind of eye drops.



Frames

Frames are an optical aid into which we put corrective lenses that improve a person’s vision. Frames can be made out of different materials. High quality “plastic” frames are made of acetate, metal frames are usually made of stainless steel or titanium.



Glasses

Yes, that is what we sell. The health insurance companies sometimes call them “optical aids”.



Hyperopia (farsightedness)

If you are farsighted, you probably find it hard to focus on near things but don’t have any problems with focusing on things at a distance (yes, it’s exactly the opposite of what you might think based on the name). Farsighted = can see far, can see distant things clearly, but struggles with things that are near.

Hydrophobic

Hydrophobic = doesn’t like water or steam. A hydrophobic coating stops the lenses from fogging up or smudging.



Iris

The iris determines your eye color. It’s a pigmented disc with the pupil in the middle of it. The color of the iris is determined by the amount and depth of the pigment. If the pigment is missing (for example due to albinism), the color seems to be pink because we can see some of the red color of the choroid. If the pigment is quite deep, the iris can be blue, grey or green. If there is a lot of pigment, the iris ends up being dark brown. The irises of one person can sometimes be multi-colored



Monocle

Monocle is a glass lens for one eye, widely used in the 19th century instead of glasses. People wearing monocles wanted to show them off and so usually wore them attached by a golden chain to the pocket of their jacket or vest.

Myopia (nearsightedness)

Nearsighted people find it hard to see people at a distance of a few meters in clear focus. Maybe you’re sitting in the back row of a cinema and the screen is blurry – it’s very likely nearsightedness is the cause. Don’t worry, it’s quite common.



Nose bridge

The nose bridge is the top part of the nose between your eyes. Everyone’s nose bridge starts in a different place and therefore it’s necessary to think about it when choosing your glasses. But don’t worry, we’ll remember to consider it when helping you choose.

Nose pads

Nose pads, usually made of silicone, sit on each side of the bridge of your glasses. Their job is to help your glasses fit perfectly on your nose. They can be adjusted, which makes a frame with nose pads easier to fit on different types of faces.



Optometrist

An educated medical professional who deals with correcting disordered vision and looking after people’s sight in general. Optometrists usually specialize in diagnosing how good a person’s ability to focus is, and they help apply contact lenses. They also perform other non-invasive diagnostic tests. If an optometrist finds out that a vision disorder isn’t created by a faulty refraction (which means that the problem can’t be fixed with glasses) they recommend that person visits an ophthalmologist.

Optician

A professional who looks after your eyes. Their expertise is in helping you pick the right glasses for you. Not just any glasses, but glasses that will fit your face and help you see better. An optician knows how to fit lenses into frames and how to fit frames to a person’s face perfectly. We have a number of these professionals at our shop, one of them named Zita. Maybe it’s not a coincidence.

Ophthalmologist

A medical doctor who specialises in the diagnosing and treatment of eye diseases. They also perform eye surgery. They can measure your vision and prescribe glasses when necessary. You only need to bring this prescription to us and we’ll help you with the rest.

Oculus Dexter/Oculus Sinister

These terms can be abbreviated into OD and OS. They are just the Latin names of your right and left eye. You can find these abbreviations on your prescription or medical record



Prism

A prism is a shape that refracts light. It’s also one of the pieces of information that appears on your prescription – more exactly it is a prismatic correction which means it’s a correction of an oculomotor variation. Lens correction with a prism is of a very high standard and can help even with disorders of binocular vision.

Polycarbonate

A polycarbonate is a transparent plastic with an extraordinary impact resistance. Some of the lenses that we use in our frames are made of polycarbonate.

Polarised lenses

Polarised lenses eliminate glare making driving in the summer much easier. How do they work? Light that hits a lens is composed of “good” vertical light that helps us see color and contrasting light and of “bad” light that moves horizontally and stops us from seeing clearly. Polarised lenses filter horizontal light which helps all of the light waves to vibrate in the same direction

Plano

Lenses without a prescription are called plano.

Pince-nez

A very old school type of glasses with no arms. The frames stay in place by pinching the nose.

Pupil

The pupil is the part of the eye that light passes through – the little black hole in the middle of your iris. People have round pupils which is not universal for all animals that can see (geckos or goats have some crazy-shaped pupils). Your pupils work like a camera aperture, expanding and contracting according to the light conditions. If there isn’t much light, the pupil expands, if there is too much light, the pupil contracts so that less light can come in. About 20% of people have pupils of different sizes.

Pupillary distance

Your “PD” (distance between your pupils) is a very useful measurement that helps align the lenses to fit the frames perfectly. If the lenses are not aligned according to the correct PD, the eyes will be made to look in the wrong direction. If you wear glasses with a wrong PD long term, it might cause your eyes to be misaligned. In an ideal world, PD would appear on your prescription every time. But don’t worry if you can’t find it on your prescription, we’ll measure your PD ourselves.

Prescription

A prescription from an ophthalmologist or an optometrist is the best way to figure out what glasses are perfect for you. It’s almost like a cooking recipe but the ingredients are different. The ‘sphere’ indicates the strength of the lens needed to help you see better -- whether it’s nearsightedness or farsightedness you need to correct. The ‘cylinder’ indicates the strength of the lens needed for correcting your astigmatism. PD indicates the distance of your pupils from your nose bridge. These are some of the basic pieces of information you will find on your prescription.

Progressive lenses

These are special made-to-measure lenses that offer a number of corrections at the same time (it’s basically more than one diopter in each one). In this way one pair of glasses can cover the whole of your field of vision without the need for changing glasses. The lower part of the lens helps you focus on the things close by, the upper side corrects your inability to focus on things at a distance, and the middle bit covers the middle distance (e.g. a computer screen). There is a smooth transition between the different corrections.



Refraction

From the physics perspective, refraction is the bending of any wave. In our case we’re talking about light waves passing from one medium to another. In eyewear terms, refraction is a process of measuring the refraction error.

Retina

The retina is a light-sensitive layer of tissue lining the inside of your eye. If your eye was a camera, the retina would be the photographic film inside.



Sphere

This information indicates the strength of the lenses needed to help your vision in such a way that the light reaches your retina. The sphere can be minus (to help you see objects that are far) or plus (to help you see objects near you).

Snellen chart

The Snellen chart is an eye chart that helps determine how well you can focus. It was created in 1862 by Dutch ophthalmologist Herman Snellen. It’s the chart with letters that you have to read with one and then the other eye closed. If you can read the last line with each of the eyes separately, you most likely don’t need glasses.



Titanium

Titanium is a metal that holds up well against any pressure. Titanium is amongst the favourite materials for making glasses because of its durability and because of how lightweight it is. Another advantage is that it never rusts.



Ultraviolet light (UV)

Ultraviolet light is an electromagnetic radiation that surrounds us but isn’t visible to the human eye. The sun is its main source and it’s damaging to the eye if we get overexposed to it. It’s a great excuse to at least buy sunglasses if you don’t have even half a diopter on your prescription.



Visual field

The visual field is the space that you can see with one eye looking ahead without moving your eye or your head. If you have a standard visual field it means that you’re able to perceive objects in 180-degree vertical and horizontal radiuses with both of your eyes.