A reminder of the design of the eye and surrounding structures (19)

Just a reminder of the design of the eye and surrounding structures:

Over the last few weeks we've been summarising the most useful facts about the most common problem of the retina (right at the back of the eye) - Age-related Macular Degeneration.

For our next blog post we will move forward all the way to the front of the eye, in fact in front of the eye - and we'll be talking about common everyday problems with the eyelids and the proven ways of managing these common, annoying, and sometimes very serious, eyelid problems. 

What is this disease called AMD ? (12)

Age-related macular degeneration (AMD) damages the central part of the retina, known as the macula. Here's a cross-section of the eye (the eye cut through from front to back):

Viewed through the front of the eye, the normal macula looks like this:

 The most common form of AMD is called "dry" AMD, It simply consists of tiny pale yellow spots in the macular area, and it looks like this:

The "dry" situation can persist, usually gradually worsening, over many many years; during this time the person may see normally or may notice a very gradual reduction in their central vision (the part needed for detailed activities such as reading, or recognising faces). But in a minority of cases it can quite suddenly convert to "wet" AMD, where blood vessels grow under the macular area, which looks like this:

 In this wet situation, the person usually notices sudden onset of distortion in their central vision, followed after some hours/days by complete loss of central vision - so suddenly they can't see to read or recognise faces. Because the wet form is heralded by distortion in the vision, people with dry AMD are often warned to come back to their eye doctor within 24 hours if they notice any  distorted vision, for example kinks in their view of door frames/window frames etc.

So the above illustrates that in both dry and wet forms of the disease, you lose your central vision, the bit you need for accurate detailed seeing; in the dry form it happens over many years, whereas in the wet form it happens over hours/days.

Concise introduction to the eye and its more common problems. (10)

Have a look at this really good simple introduction to the eye and its more common problems:


CLICK HERE

The blog you're reading now is the place to come for proven facts on how to care for your eyes and your vision, so they last your lifetime - which is essential. (8)

If you want proven facts about how best to care for your eyes and vision, together with references to the scientific evidence underpinning those facts so you can have confidence that the steps you're going to take are going to work, this blog you're looking at now is the place to come.

Scroll up and down, use the search facility top left, and click some of the links to view information presented by other eye and vision professionals who are doing the same thing - bringing evidence-based useful information to you.

We and our doctors will keep on searching, sifting the evidence-based facts from the ocean of hearsay myth out there, and we'll bring you the proven information in readily digestible form so you can use it to care for your eyes and your vision.

That's our mission.

To good vision - for life - for everyone.

The Eye Care and Vision Team
St. Albans Medical Centre
St. Albans, U.K.

Tel: + 44 (0)1727 812925
Email: Contact@StAlbansMedicalCentre.com

If you have long-term itchy, uncomfortable eyes/eyelids, the most likely cause is Blepharitis. (1)

The most common reason for people to have long-term itchy or slightly uncomfortable eyes is inflammation in the skin around the bases of the eyelashes i.e. at the lid margins, and is called Blepharitis.

Blepharitis is not usually due to tissue infection, but rather is due to inflammation only. However, organisms (usually bacteria or yeasts) on the skin surface do play a part in causing the inflammation.

It can develop at any age, and symptoms can include:

• itchy, sore and red eyelids that stick together
  
• crusty or greasy eyelashes
• a burning, gritty sensation in your eyes
• increased sensitivity to light (photophobia)
• swollen eyelid margins
• finding contact lenses uncomfortable to wear
• abnormal eyelash growth or loss of eyelashes in severe cases

In most cases both eyes are affected, but one eye can be more affected than the other. The symptoms tend to be worse in the morning.

Blepharitis is usually a long-term condition. Most people experience repeated episodes, separated by periods with reduced symptoms.

Blepharitis isn't contagious.

What causes blepharitis?

Blepharitis is usually an interaction between oils produced by the eyelid glands and the bacteria/yeasts that live on the glands. Occasionally an aggressive bacterium (Staphylococcus Aureus) is a significant part of the cause, and in these cases a few days of treatment with antibiotic (ointment rubbed into the lashes twice per day) is very helpful.

Blepharitis can be divided into three types: Anterior, posterior, and mixed (anterior and posterior). The subdivision into these three types is not clinically very useful because 

i) the mixed type is by far the most common, and

ii) the treatments outlined above are used effectively for all three types.

Sometimes blockages in the Meibomian glands are associated with a skin condition called rosacea. If too much oily substance is being produced, this may be caused by seborrhoeic dermatitis which commonly affects other areas of the body (e.g. the face and/or scalp) and many people with itchy eyelids due to blepharitis also have itchy, flaky ("dandruff") scalp.

When to get medical advice

See your high-street optician (optometrist) or an eye specialist if you have persistent symptoms of blepharitis that aren't being controlled by simple eyelid hygiene measures.

If you have severe symptoms (for example severe redness or lid swelling), contact your optometrist or GP immediately. If this isn't possible, visit your nearest accident and emergency (A&E) department.

How blepharitis is treated

A tendency to blepharitis can't be cured, but the condition can be completely controlled - it's exactly the same idea as washing your hair regularly to prevent itching and inflammation of your scalp, and a daily eyelid-cleaning routine can help control the symptoms and prevent permanent scarring of the eyelid margins.

There are three main steps to eyelid hygiene that should be performed, morning and evening to start with, and then most people find that about three times per week is enough to keep control of it: 

• using a warm compress – to make the oil produced by the glands around your eyes more liquid so it can flow out of the glands instead of blocking them. Heat pads that can be warmed in the microwave and rested on your closed eyelids have been proven to be very effective in reducing/removing symptoms and preventing long-term complications of blepharitis.
• gently massaging your eyelids – to push the oils out of the glands
• cleaning your eyelids – to wipe away any excess oil and remove any crusts, bacteria, dust or grime that might have built up

More severe cases may require antibiotics that are either applied to the eye or eyelid directly, or taken as tablets.

Complications

Blepharitis isn't usually serious, although it can lead to a number of further problems.

In the next post (above) we'll begin to look at the more serious problems that can occur if blepharitis remains untreated for years, and therefore why the relatively simple treatments outlined above should be commenced whilst the condition is mild - if you have irritating eyes, don't put up with it - get it sorted.

How is the name "Blepharitis" derived ?

Inflammation is the response of the body to noxious stimulus (chemical/injury/infection).

The Greek word for eyelid is "blephar" and the suffix "-itis" (again from Greek) is appended (as it is to the name of any body structure) to indicate inflammation. 

Authoritative government source: 

http://www.nhs.uk/conditions/Blepharitis/Pages/Introduction.aspx