EYE CONDITIONS EXPLAINED


Please note: All of the following descriptions are for information, knowledge, interest and awareness but should not be used to self diagnose. Always consult a professionally qualified optician.

Myopia

Myopic means short sighted.

A myopic person has clear vision when looking at objects close to them, but distant objects will appear blurred.

Light from a distant object forms an image in the eye too soon before it reaches the retina. This could be because the eye is too long, or the cornea or crystalline lens is too strong.

A concave, minus powered lens is placed in front of a myopic eye, moving the focus point of an image back to the retina making it appear clearer.


Hyperopia


Hypermetropic means long sighted (hypermetropia is often shortened to hyperopia).

Condition of the eye where rays of light reach the retina before they have converged into a focused image. This could be because the eye is too short, or the cornea or crystalline lens is not strong enough.

A long sighted person's close vision may be more blurred than their distance vision but both can be affected. By placing a convex, plus powered lens in front of a hypermetropic eye, the image is moved forward and focuses correctly on the retina.

 

Presbyopia

Condition where the eye progressively loses it's ability to change focus between distance vision and near vision.  This typically becomes apparent when a person approaches their mid forties.  A different power lens will now be needed to correct distance vision compared to reading/near vision.  Even if a person has never needed glasses for general vision previously they will start to become presbyopic and need reading glasses at some point over the age of 40.

Someone who is presbyopic might have different strength single glasses for distance and reading or may have varifocal (progressive) specatacles or multifocal contact lenses.

 

Astigmatism

Astigmatism is the optical term for more than one point of focus.  It occurs when the surface of the cornea (or sometimes the crystalline lens) is not spherical and is more curved in one direction than the other.  You may often hear this described as the eye being rugby ball shaped rather than football shaped, this is an exagerrated analogy and would not be noticable in the physical appearance of someone's eye. 

To correct astigmatism a toric or cylindrical lens is used (this is what the 'cyl' part of a prescription refers to) to correct any distortion to the person's vision.

Astigmatism may be present as well as myopia, hyperopia or presbyopia.  Most prescriptions will show at least a small amount of astigmatism.


Cataracts

A cataract is when the crystalline lens in the eye gradually becomes cloudy and more opaque. The lens is normally clear and sits behind the iris. The lens helps focus light to produce a sharp image on to the retina at the back of the eye and changes shape to allow you to refocus. A cataract acts a bit like a frosted glass coating that scatters light, causing blurring and lack of clarity.

Cataracts are painless and usually cause a gradual worsening of sight.

Vision may become misty or hazy so that you cannot see details at a distance.

Vision may be difficult in low light and bright light may cause glare or 'starburst' effects.

Double vision may occur for either close or distance objects.

Colours may start to appear faded or washed out.

In theory anybody who lives long enough will eventually develop cataracts although age onset is not the only cause, for example excessive UV exposure can be one of the causes.

Please note: The descriptions of this condition is for information, knowledge, interest and awareness but should not be used to self diagnose. Always consult a professionally qualified optician.

 

Conjunctivitis

Conjunctivitis is an inflammation of the conjunctiva. The conjunctiva is the thin layer that covers the white of the eye and the inside of the eyelids. It can affect one or both eyes, causing discomfort.

The causes of conjunctivitis can be bacterial, viral, allergic or from another source. If you have mild symptoms of discomfort, a red eye and some white/yellow/green discharge, you can usually treat it with over the counter antibiotics from your pharmacist. Any pain or severe redness or inflammation should be checked out by your GP or optician immediately. Conjunctivitis can be very contagious, so its important to wash hands thoroughly after touching your face and try not to share towels and face-cloths.

Please note: The descriptions of this condition is for information, knowledge, interest and awareness but should not be used to self diagnose. Always consult a professionally qualified optician.

 

Diabetes

Diabetes can lead to a condition called Diabetic Retinopathy as well as other eye problems. Diabetic retinopathy (damage to the retina) is caused by complications of diabetes mellitus, which can eventually lead to blindness.

It is an ocular manifestation of systemic disease, which affects up to 80% of all patients who have had diabetes for 10 years or more. Research indicates that at least 90% of new cases could be prevented if proper treatment and monitoring of the eyes is carried out on a regular basis.

Regular eye tests can help to spot the early signs of this condition and enable you to take action to control diabetes before it damages your body and your eyes.

Please note: The descriptions of this condition is for information, knowledge, interest and awareness but should not be used to self diagnose. Always consult a professionally qualified optician.

 

Floaters

The eye is filled with a clear, watery jelly-like substance called the vitreous humour that helps maintain the eye's shape. Debris within the vitreous humour casts a shadow on the retina at the back of the eye, and appears to 'float' in your field of vision. Floaters can appear in a variety of shapes and sizes such as dots, smoke, shadow or hairs. They are more visible against clear, pale backgrounds such as white walls or blue sky. They move when your eye moves in different directions and seem to dart away when you look at them.

Most floaters are small but larger floaters can be annoying and make activities that require higher concentration, such as reading or driving more difficult. Although most people naturally experience floaters, they are usually harmless.

They can however also be caused by a Posterior Vitreous Detachment (PVD) or a detachment or tear of the retina (the light sensitive tissue inside the eye), oher symptoms could possibly be experienced such as flashing lights, coloured 'sparkles', temporary loss of vision, blind spots and sudden 'showers' of floaters or cobweb effects.  If someone is experiencing a combination of these symptoms they may need urgent attention.

Please note: The descriptions of this condition is for information, knowledge, interest and awareness but should not be used to self diagnose. Always consult a professionally qualified optician.

 

Macular Degeneration

The macula is a small area in the middle of the retina with the greatest amount of light sensitive cells and is used for fine-detailed central vision. Macular degeneration is a painless disorder that can affect either eye, causing progressive loss of central and detailed vision.

Age-Related Macular Degeneration (AMD) is the most common form, although some forms affect younger people. There are two main types of AMD, referred to as 'wet' and 'dry'. This is not a description of how the eye feels, but of whether leaking blood vessels are involved. Dry AMD accounts for 90% of cases, with 10% being Wet AMD.

Wet AMD can cause a sudden onset of symptoms over days, resulting from a build up of fluid under the retina. Dry AMD progresses slowly over a number of years and the symptoms will onset gradually and includes blurred or absent central vision.

Please note: The descriptions of this condition is for information, knowledge, interest and awareness but should not be used to self diagnose. Always consult a professionally qualified optician.

 

Glaucoma

Glaucoma is a group of eye diseases characterized by damage to the optic nerve usually due to excessively high intraocular pressure (IOP).This increased pressure within the eye, if untreated can lead to optic nerve damage resulting in progressive, permanent vision loss, starting with unnoticeable blind spots at the edges of the field of vision, progressing to tunnel vision, and then to blindness.

Please note: The descriptions of this condition is for information, knowledge, interest and awareness but should not be used to self diagnose. Always consult a professionally qualified optician.

 

Blepharitis

Inflammation of the eyelids. Blepharitis occurs in two forms, anterior and posterior. Anterior blepharitis affects the outside front of the eyelid, where the eyelashes are attached. The two most common causes of anterior blepharitis are bacteria and scalp dandruff. Posterior blepharitis affects the inner eyelid (the moist part that makes contact with the eye) and is caused by problems with the oil (meibomian) glands in this part of the eyelid. Two skin disorders can cause this form of blepharitis: rosacea and seborrheic dermatitis.

Please note: The descriptions of this condition is for information, knowledge, interest and awareness but should not be used to self diagnose. Always consult a professionally qualified optician.

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