Eye tests for glaucoma

Glaucoma: a group of eye conditions that affect vision, often affecting both eyes, usually in varying degrees. One eye may delelop glaucoma quicker than the other.

Glaucoma occurs when the drainage tubes within the eye become slightly blocked. This prevents eye fluid from draining properly.

When fluid can't drain properly, pressure builds up. This is called intraocular pressure and can damage the optic nerve and the nerve fibres from the retina.

There are two tests for inner eye pressure. The first one is used at the optitians.

Tonometry - Eye pressure test uses an instrument called a tonometer to measure the pressure inside the eye. A small amount of pressure is applied to the eye by a tiny device giving a warm puff of air. A blue light from the head of the tonometer is held against your eye to measure the intraocular pressure. 

OR 

A small amount of anaesthetic and dye is placed onto the cornea. A blue light from the head of the tonometer is held against the eye to measure the intraocular pressure.

Positive result - Tonometry can diagnose ocular hypertension, which is a risk factor for chronic open-angle glaucoma.

Ophthalmoscopy (dialated eye exam) - The optic nerve connects your eye to your brain. Your optometrist will use eye drops to enlarge your pupils. They will then examine your eyes using a slit lamp and assess whether your optic nerve has been damaged by the glaucoma.

The eye drops used to widen your pupils could affect your ability to drive.

Perimetry (visual field test) - checks for missing areas of vision. You will be shown a sequence of light spots and asked which ones you see. Some dots will appear in your peripheral vision, which is around where glaucoma begins.

Positive result - If you cannot see the spots in your peripheral vision, it may indicate the glaucoma had damaged your vision.

Gonioscopy - an examination of the front outer edge of your eye, between the cornea and the iris. this is the area where the fluid should drain out of your eye.

Positive result - Can help determine whether this angle is open or closed (blocked).

Pachymetry - The thickness of your cornea will be measured because this is thought to affect how the intraocular pressure is determined.

Long sightedness, also known as hyperopia, affects a person's ability to see objects close to them.

Vision problems such as long sightedness are often referred to as refractive errors.

If you are long sighted, you will usually be able to see distant objects clearly, but nearby objects will be out of focus. Your eyes  will also tire easily.

If you wear glasses or contact lenses, your vision will be tested both with and without them. The optometrist will usually assess your distance vision, your near vision and your intermediate vision. A simple visual acuity test will help the optometrist assess how good your vision is.

You may be asked to read from a snellen chart, which is a series of letters that become progressively smaller on each line. Your optometrist will then carry out further tests to determine the extent of your problem and the exact type of corrective lenses that you need.

A common eye condition that cases distant objects to appear blurred, while close objects can be seen clearly.

It's thought to affect up to one in three people in the UK and is becoming more common. 

The medical term for short sightedness is myopia.

Cases can range from mild, where treatment is not required, to severe, where a person's vision is significantly affected.

The symptoms of short sightedness often start around puberty and gradually get worse until the eye is fully grown.

To measure how severe your short sightedness is, your optician will use a test called retinoscopy, where a bright light is shone in your eye to see how your retina reacts. 

You may also be asked to look at a chart through a series of different strength lenses to see how they affect your vision. This will help the optician to determine the strength your prescription should be.