Your Essential A to Z Guide to Eye Health

Article by Chew’s Optics Specialist. 27 April 2023


Some folks believe in the old adage that ignorance is bliss. But when it comes to your health and well-being, it’s quite the opposite. The more you know, the better off you’ll be.

Whether it’s to equip yourself with the right information to prevent illness, or to simply understand your body a little better, we’ve put together a quick A to Z guide for you to learn more about eye health.

Here’s introducing a beginner’s glossary of all the eye care and vision-related terms you need to know.

Our Eye Health Glossary

A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | PR | S | T | U | V | W | X | Y | Z


Astigmatism: Astigmatism refers to the abnormal curvature of the eye. This condition is a type of refractive error that can be inherited or developed over time, causing your vision to be blurred or distorted.


Bifocal lens: A pair of spectacles or contacts with bifocal lenses contains two different optical powers. The top section of the lens typically allows you to see at a distance, while the bottom section of the lens allows you to see things clearly up close.


Cataracts: Cataracts occur when the lens of your eye becomes cloudy. This condition, which affects individuals of all ages (not just the elderly), is nonreversible and can only be corrected through surgery.


Dry eye: Dry eyes occur when there is insufficient moisture or lubrication in the eyes. In other words, you are either not producing enough tears or producing low-quality tears – leading to eye inflammation and discomfort.


Emmetropia: Also known as perfect vision, emmetropia is a condition where an individual is able to see near and distant objects clearly with minimal effort. Someone with emmetropia has no astigmatism, nearsightedness or farsightedness.


Floaters: Floaters are dark spots that float across your field of vision. They can take the shape of wavy lines, webs and clouds, and are more common for older-aged individuals. If they disappear after a short while, they are no cause for concern. If not, they can be a sign of a serious eye condition.


Glaucoma: Glaucoma is an eye disease where fluid builds up in the front area of your eye, which increases intraocular pressure. This leads to optic nerve damage (meaning vision loss or blindness), where any loss of vision is irreversible.


Hyperopia: Hyperopia, also known as farsightedness, is a condition where your eyes are able to see distant objects clearer than near objects. It can affect all individuals of all ages.


Intraocular pressure: Intraocular pressure refers to the pressure inside the eyes. Although a certain amount of pressure is needed for your eyes to function properly, abnormally high eye pressure can be a sign of glaucoma.


Jackson’s cross cylinder test: This is an eye test conducted by optometrists, where an instrument known as a Jackson cross cylinder is used to determine the corrective lens power for individuals with astigmatism.


Keratoconjunctivitis: This is an eye condition where both your cornea and conjunctiva (a thin membrane that protects your eye) are inflamed. It can be infectious or non-infectious, but would typically require eye drops to treat.


Low vision: Low vision refers to a loss of visual acuity. Unlike conditions such as nearsightedness and farsightedness, low vision cannot be corrected with spectacles, contact lenses or surgery.


Macular degeneration: Macular degeneration is an eye disease that affects the macula, which is the central part of the retina that allows you to see fine details. Typically an age-related condition, it can lead to the loss of central vision.


Neovascularization: This is a process that refers to the growth of new blood vessels in various parts of the body, including the retina and cornea. When there’s too many of them, it can lead to vision loss. Optometrists are equipped to check for signs of this condition.


Optometrist: An optometrist is a healthcare professional who offers primary eye care services. They are able to perform both comprehensive eye examinations and simple vision tests, prescribe spectacles and contact lenses, and most importantly, diagnose common eye diseases and infections. To consult an optometrist, you can head to Chew’s Optics in Singapore.


Pinguecula: A pinguecula is a yellowish, noncancerous growth in the white of your eye, which may lead to redness or irritation. Thought to be caused by overexposure to the sun’s harmful UV rays, it can be prevented with the regular use of UV-protected sunglasses.


Retinal detachment: Retinal detachment occurs when there is a tear in the retina, causing fluid to seep under the retina and separating the retina from the wall of the eye. Early treatment of such a condition is crucial to preventing permanent vision loss.


Strabismus: Strabismus is a disorder more commonly known as crossed eyes, where the eyes do not line up with each other. Individuals – infants and toddlers in particular – with severe farsightedness or poor eye muscle control have a higher risk of developing strabismus.


Toric lens: Made for individuals with astigmatism, toric lenses are specialty contact lenses that accommodate the abnormal shape of a person’s cornea. They can come in the form of dailies, monthlies, coloured, conventional and rigid gas permeable lenses.


Uveitis: Uveitis is a condition where your uvea (the middle layer of your eyeball) becomes inflamed. It often occurs when your immune system is battling an eye infection, and can affect either one or both eyes.


Visual acuity: Visual acuity refers to your eye’s ability to see the fine details of objects at a certain distance. In short, it measures the sharpness of your vision. This is among the basic eye tests that are usually administered as part of a comprehensive eye examination.


White pupillary reflex: Also known as leukocoria, white pupillary reflex occurs when there is a white reflection in one or both pupils of the eye. Most commonly found in kids, it can be a sign of retinoblastoma (a form of eye cancer that can spread to other areas of the body).


Xanthelasma: A xanthelasma refers to a yellow growth on or near the eyelids. They often manifest as soft bumps, forming when deposits of cholesterol build up in your blood vessels. Although they are largely harmless, they may be an indication of early heart disease.


Yellow eyes: Yellow eyes are a symptom of jaundice, where high levels of bilirubin leads to the yellowing of the skin and the whites of your eyes. This condition is typically associated with liver damage or disease.


Zonules: Zonules are small, thread-like fibers that connect the eye’s lens to the inner wall of the eye. This ligament works to help your eyes focus, relaxing when looking at a distance and tightening when viewing objects up-close.

Looking for an eye health expert? Meet the optometrists of Chew’s Optics.

If you need more help than an online glossary is able to offer, visit our certified and highly experienced optometrists at Chew’s Optics.

You can walk in to our optical shop at 144 Teck Whye Lane, #01-211, Singapore. We’re open daily except for Mondays.

Alternatively, book an appointment with us  here or reach out to us on WhatsApp at  +65 8314 7093.

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