Introduction to posterior blepharitis

Posterior blepharitis, also known as meibomitis, is a common sub-acute or chronic inflammation of the eyelid margins, usually involving the oil glands (meibomian glands), the tarsal plate, and the blephero-conjunctival junction in the eyelids. Sometimes the terms ‘posterior blepharitis’ and ‘meibomian gland dysfunction’ are used interchangeably due to significant overlap between the two conditions.¹

Blepharitis is caused by increased bacterial colonization. As bacteria replicate, they form organized colonies called biofilms, consisting of billions of active replicating bacteria. The bacteria produce a special, sugary coating called glycocalyx that helps them adhere to the eyelids and meibomian glands and communicate with each other. As these colonies grow on the eyelids, the bacteria release highly inflammatory toxins that trigger an immune response, leading to red, irritated eyelids with dilated blood vessels, crusts at the base of the eyelashes, and clogged meibomian glands.²

Some people are highly sensitive to the bacteria on the skin, resulting in strong immune responses and severe signs and symptoms of blepharitis. 

Anatomy and function of the eyelids

Blepharitis commonly occurs when the tiny oil glands located on the edge of the eyelids become clogged or irritated, resulting in red eyes. The eyelids are folds of skin that keep the eye safe from debris and injury. At the edge of the lids are lashes with short, curved hair follicles, and meibomian glands.

The surface of the eye needs a mixture of oils and tears for adequate lubrication and comfort. There are about 30 meibomian glands in the upper and lower eyelids,  located where the lashes are. These glands produce the oil for tears, preventing them from evaporating too quickly. In conditions like blepharitis, the glands become clogged with bacteria and dead skin cells, leading to poor-quality oil that becomes crusty and obstructs the glands. The tears are crucial for clear vision. In blepharitis, the skin has a lot of staphylococcus and streptococcus. This can often produce a toxin that can be really irritating to the surface of the eye. This can result in inflammation, scaling and crusting of the eyelids.³

Causes and risk factors

Chronic meibomitis is a commonly occurring meibomian gland dysfunction which is seen more commonly in middle-aged individuals. Acute meibomitis occurs due to staphylococcal infection and is characterized by painful swelling around the gland.⁴

It is a common condition that can develop at any age but is more prevalent in young children and people older than 50 years of age. Other risk factors also include environment, hormones, immune system and nutrition can all play into the development of blepharitis. Research studies have found that individuals who work in office environments with a lot of air conditioning or if they are spending a lot of time on computers are more highly at risk for the development of blepharitis.⁴

Nutrition also plays a key role in the development of blepharitis. Omega-3 and omega-9 fatty acids may help prevent blepharitis or make symptoms better. 

Other causes include:

• Oily skin
• Rosacea
• Ocular allergies
• Dandruff 

Symptoms of posterior blepharitis

• Chronic irritation
• Burning 
• Itching
• Grittiness
• Mild lacrimation
• Light sensitivity 
• Dryness 

Some of the more serious consequences of having posterior blepharitis are:

• Lash loss 
• Misdirected lash growth - also known as trichiasis 
• Blurry vision
• Swelling of other parts of the eye like the cornea⁵

Diagnosis of posterior blepharitis

To make a diagnosis the doctor will carry out a physical examination. During the physical examination, the doctor will carefully examine your eye and eyelid. The doctor may use a slit lamp which is a specially developed, low-power microscope with an intense beam of light. In certain cases, the doctor may collect a swab sample of the oil or crust that forms on your eyelid. This sample can be analyzed for bacteria, fungi or proof of an allergen.⁶

Clinical features include:

• Obstructions and plugging of meibomian orifices 
• Thickened, cloudy expressed meibomian secretions
• Injection of lid margin and conjunctiva
• Tear film abnormalities and punctate keratitis

Treatment options and long-term care

Treatment options mostly include medical and home remedies.

Self-care and home remedies

Eyelid hygiene via warm compress and cleaning the eyelids is essential. A warm compress is critical to soften the meibomian gland oil which allows improved gland secretion. Research studies show that the meibomian glands should be heated up to 41 degrees Celsius to liquify all the oily secretions in our glands.

One of the most consistent, efficient and cost-effective ways to do this is using an electrical warm compress device such as the aroma season therapy device which can be found on Amazon for about 20 minutes, twice a day. The warm compress is then followed by a gentle eyelid wipe to remove and exfoliate all the debris and bacteria from the eyelashes. Gentle side-to-side motions tend to get rid of the debris. ⁷

Medications

If symptoms continue patients are prescribed an antibiotic ointment such as erythromycin ophthalmic ointment which must be applied to the base of the eyelashes twice a day. This ointment helps to decrease the levels of bacteria on the skin which helps to reduce the inflammatory response to the bacteria.  The eyelid hygiene regime and a course of erythromycin treatment should be done in parallel for several weeks to a few months. The patient is then assessed on how the patient is responding to treatment.⁸

If a patient is suffering from an acute flare-up of their blepharitis with significant eye redness, pain and inflammation then the doctor may consider prescribing a combination steroid antibiotic ointment such as maximal or abrades. The steroid in the ointment helps to calm down the eyelid inflammation while the antibiotic helps to kill off bacteria. This is usually effective but the patient needs to be careful as long-term use of steroid ointments can increase the risk of side effects such as increased eye pressure and early cataract formation.⁸

Additionally, oral antibiotics are also considered for blepharitis sufferers. The most common oral antibiotic is doxycycline which is taken twice a day over the course of six weeks, although recent research has shown that azithromycin is another promising alternative. Doxycycline as an antibiotic helps to reduce the number of bacteria on the eyelids and it also has been shown to decrease the activity of matrix metalloproteinase 9 (MMP9), which is an enzyme that contributes to inflammation. Hence doxycycline has both anti-bacterial and anti-inflammatory properties. The problem with doxycycline however is that it can cause sensitivity to the sun hence patients need to make sure they wear plenty of UV protection like wide-brim hats, sunglasses and sunscreen in order to prevent sunburns. Other common side effects are nausea, decreased appetite, diarrhoea, yellowing of the teeth and slow down the growth of bones.⁸

Research studies comparing doxycycline and azithromycin show that a significantly smaller percentage of patients experience side effects on azithromycin compared to doxycycline when being treated for blepharitis. Azithromycin also does not cause teeth discolouration and bone growth slowing as doxycycline does. Azithromycin is just as effective in improving blepharitis and meibomian gland dysfunction symptoms while also having less frequent side effects.⁸

Summary

Posterior blepharitis causes dry eyes due to blocked glands. Eyes with blepharitis can be stuck first thing in the morning. There is no cure for this however it can be managed through various techniques. These techniques include hot compress, eyelid hygiene and even prescribed medication. Blepharitis is not sight-threatening for example it will not cause permanent damage to the eyesight. However, it can result in permanent alterations of the eyelid margins.

FAQs

Is blepharitis contagious?

No, the disease may be uncomfortable and unsightly but it is not contagious. 

What aggravates blepharitis?

Air-conditioned environments such as the office, windy weather, long hours of screen time, dehydration and sleep deprivation are all things that can lead to blepharitis. 

What is the difference between posterior blepharitis and meibomian gland dysfunction?

Posterior blepharitis affects the front of the eyelids whereas meibomian gland dysfunctions affect the back of the eyelids.w