Anatomy of the Eye

We may take them for granted but our eyes are one of the most sophisticated organs in the human body. Many of us know very little about them but understanding our eyes and our vision system can help us better protect them, and prevent disease and other vision related problems from occurring.

Although it is small in size, the eye arguably provides us with the most important of the five senses – vision. This section gives an overview of the anatomy of the eye and how the eye works.


Common Eye Conditions


A refractive condition of the eye in which vision is better for distant objects than for near objects. It can be called far sightedness or hypermetropia.

Symptoms of Hypermetropia can include; blurred vision, asthenopia (eye strain), accommodative dysfunction, binocular dysfunction, amblyopia and strabismus.

It results from the eyeball being smaller than average, causing images to be focused behind the retina. Hypermetropia should be diagnosed by a qualified Optometrist, Ophthalmic Surgeon or Eye Specialist. A full Optometric Examination should be performed to assess the degree and extent of the problem. Eyeglasses and contact lenses are the treatment of choice for most people with far sightedness but refractive surgery can also cure some cases of hyperopia.



Myopia is a common refractive condition which causes individuals to be nearsighted: they see near objects clearly, but distant objects are blurry.

Myopia occurs when the cornea and lens focus the light in front of the retina instead of exactly on it. Symptoms of myopia include; difficulty seeing distant objects, squinting frequently, holding books or other objects very close to the face, difficulty seeing writing on signs or watching television and difficulty with driving (particularly at night). Myopia should be diagnosed by a qualified optometrist, Ophthalmic Surgeon or eye specialist. Myopia is best treated with eyeglasses or contact lenses which compensate for the elongated shape of the eye allowing the light to focus properly on the retina. Refractive surgery is another option that eliminates dependence on glasses or contact lenses.



Presbyopia is a vision condition which makes it difficult to focus on close objects. During middle age, usually beginning in the 40s, people experience blurred vision at near points, such as when reading, sewing or working at the computer.

Presbyopia is a natural part of the ageing process of the eye. It is not a disease, and it cannot be prevented. Presbyopia is diagnosed with a routine eye examination. Eyeglasses with bifocal or progressive addition lenses are the most common correction for presbyopia.


Age Related Macular Degeneration

This is overall the most common cause of poor eyesight in the western world. It usually occurs in the elderly but may be seen in people as young as 50.

At Cathem we are able to offer a comprehensive diagnostic service and treat the retina where this is possible. It does regrettably remain the case that many eyes cannot be treated, yet there are some that respond very well to laser, injections or occasionally even surgery. All proven treatments are available at Cathem.



Having a cataract is a bit like having a dirty windscreen on a car. It can make the view cloudy or foggy or sometimes blurry. It can also cause glare from bright lights, sunshine, and on-coming headlights while driving. When these problems make your normal daily activities difficult, it is time consider the cataract operation. Modern small incision cataract surgery is highly successful for the great majority of patients. Cataracts do not permanently impair your vision and you will not go blind from a cataract. An operation will restore your sight. Most forms of cataract develop in adult life, and usually occur as we get older.



In most cases, astigmatism can be corrected by wearing properly fitted spectacles or contact lenses. Milder astigmatism may not need treatment unless the person is doing a job that puts intensive demands on their eyes, for example, computer work. In some cases, astigmatism can be corrected by an operation called refractive surgery, which reshapes the cornea.


Is an abnormal mass of tissue arising from the conjunctiva of the inner corner of the eye that obstructs vision by growing over the cornea. It may grow large enough to threaten sight, it can be removed surgically.


This is a cyst on the eyelid, and happens when one of the glands gets blocked and leads to swelling, and it can be of variable size. For the first few days the cyst is inflamed and you might see a small white head on the top of it which then tends to shrink, but might take months to disappear completely. This is not a serious condition and no action is required in most cases. Initially hot compresses with massaging of the area in addition to an antibiotic ointment are all that is required. If the cyst is very big to start with and doesn’t drain or if it tends to persist for months and is bothersome, it is best removed surgically.


Floaters are shapes which people can see drifting across their vision. The exact form of these is very variable – they may appear as small dots or irregularly shaped strands. Generally people should not be concerned about seeing one or two floaters in their vision, particularly if they have been there for some time. A sudden increase in the number of floaters, especially if you also see white flashing lights, is seen with posterior vitreous detachment. You should contact an eye specialist to see advice.


Glaucoma is one of the world’s leading causes of blindness. Glaucoma is an eye condition characterised by loss of vision due to damage of the optic nerve. The optic nerve carries sight images to the brain and any damage to the nerve results in damage to sight. If you have been diagnosed with Glaucoma, it does not mean you will go blind. Drops and sometimes operations can stabilise the glaucoma, and, with regular check-ups, you will be able to manage the condition. You will experience some degree of sight loss but it will be minimised with effective treatment. Treatment aims to reduce the pressure in the eye either by helping the fluid to drain away or by reducing the amount of fluid produced.


Blocked Tear Duct

The tear ducts don’t have much spare capacity and this is why we cry. The channels tend to become narrower with age, especially if there has been nose or sinus disease. An obstruction to the tear duct will give you a watery eye. A dacrocystorhinostomy (DCR) is a surgical procedure for restoring adequate drainage and relieving your symptoms.


A common condition that causes inflammation of the eyelids and can affect people of all ages. It usually affects both eyes on the edge of the eyelids and although rarely serious, it can be an uncomfortable, persistent and irritating problem. Blepharitis can cause scaly and crusty eyelids and cause the eyes to feel tired and gritty or become uncomfortable in sunlight or smoky atmospheres. It is often associated with skin conditions such as rosacea and eye conditions like conjunctivitis. Blepharitis can relapse at any time, however you can usually deal with symptoms at home and eyesight is very rarely affected. You might be prescribed a combination of treatments depending on the type of blepharitis: anterior or posterior.


General Eye Health

Regular eye checks should provide the basis for maintaining proper eye health, as some of the serious eye conditions do not have any visible early warning symptoms. However, while prevention is the best defense, problems or injuries can occur suddenly and unexpectedly. The ability to recognise signs and symptoms and also knowing what to do could be crucial to preserving sight.

Any patient who is worried or unsure about his or her individual circumstances should seek specialist advice.