Blepharitis comes from the Greek words 'blepharon' (eyelid) and '-itis' (inflammation). Therefore, it means inflammation of the eyelids. 

Blepharitis is a very common disorder that is not often diagnosed as the ophthalmologist frequently fails to do a meticulous examination of the edges of the eyelid, a very important part of the eye's surface. 

The symptoms of blepharitis are unspecific and varied: 

• Red eye and a burning sensation after prolonged used of the computer, screens, or hours of reading. 
• Feeling of a foreign body when you wake up or of stinging and swelling of the eyelid edges. 
• Excessively watery eyes when exposed to cold climates, a windy environment, heating, air conditioning or pollution.
• Recurring styes.
• Fluctuating vision or glare.
• Reduced visual acuity, photophobia, blepharospasm and pain in extreme cases. 

Various conditions are associated with blepharitis like rosacea, atopic dermatitis, psoriasis, inflammatory bowel disease, seborrhoeic dermatitis, the menopause, hormone problems, chronic use of contact lenses or topical medication for glaucoma containing prostaglandins. Prolonged computer and screen use is also a common cause of blepharitis due to reduced blinking. 

Various types of oral medication have also been associaed with these disorders like the contraceptive pill, antidepressants, antipsychotics, antihistamines, chemotherapy, anti-androgen pills like Finasteride and skin medication like Isotretinoin used for acne. 

Previous eye surgery like refractive surgery, cataract surgery or multiple eye surgeries might also be a risk factor due to the reduced sensitivity of the cornea which causes the rate of blinking to lower. 

Blepharitis can be anterior, which is when it affects the base of the eyelashes, or posterior, which is when it affects the Meibomian glands. 

Anterior blepharitis is divided in various types: seborrheic (a fatty material similar to dandruff), infectious (generally due to a staphylococcal infection, sometimes a fungus infection) or parasitic (Dermotex infestation). A lack of hygiene is associated with the infectious type of anterior blepharitis.  

Posterior blepharistis involves the Meibomian glands, which secrete fats. Fats play a very important role in the homeostasis of tears. Therefore, when there a dysfunction of the Meibomian glands either due to a blocked gland pore or atrophy, evaporative dry eye may occur. 

A meticulous inspection of the edges of the eyelid is important in order to diagnose what type of blepharitis the patient has. The specialist will perform some tests like swab cultures and senstitivity tests in the case of infectious blepharitis or take samples of the eyelashes to verify the presence of Demodex folliculorum.

Other specialist tests include interferometry, tear film break-up time and osmotic concentration to check the quality of the tears. Imaging tests like a meibography to determine the existence of Meibomian gland atrophy may also be requested by a dry eye specialist. 

Good eyelid hygiene is key in the prevention of blepharitis, especially among those who are predisposed to the abovementioned condition. Hygiene means using wet wipes and washing the eyelids with a saline solution is recommended. This is especially important for women who wear make up on the eyes. 

We also recommend that you avoid applying makeup to the internal edge of the eyelid, as this can obstruct the pores of the Meibomian gland and cause obstructive Meibomian gland dysfunction. 

A diet rich in Omega 3 fatty acids for healthy functioning of the Meibomian glands. Salmon, tuna, sea bass, sardines and the majority of seafoods are rich in Omega 3 fatty acids. The alternative sources of Omega 3 found in the diet include nuts, seaweed, chia seeds and linseeds.

Treatment must be individualised and aimed at the cause of the disease. 

Anterior blepharitis is treated with good eyelid hygiene: using special wet wipes. In cases of infection, a specialist may prescribe some topical antibiotics, especially in cases of staphylococcal infection. They can also prescribe tea tree products for cases of Dermotex infestations. Microexfoliation may also be recommended in stubborn cases or when eyelid hygiene requirements are not met.

In terms of posterior blepharitis, treatment is usually tepid compresses and eyelid massages. In some cases, the specialist may offer intense pulsed light therapy (IPLT) for cases that do not respond to conventional treatment. 

In both anterior and posterior blepharitis, Tanto en la blefaritis anterior como en la posterior, a supplement with tears may be required until the quality of the patient's own tears improves.