Two of the most common
diseases of eye are Blepharitis and Dry eye syndrome they both leads to lack of
natural tear production. Blepharitis is an inflammation of the eyelids in which
the eyes become red, irritated and itchy. Blepharitis is caused due to the
growth of bacteria that live along the margins of the eyelids and at the base
of the eyelashes. Over time, these bacteria build up and create a structure
called a biofilm. This biofilm becomes a toxic environment like the plaque. Its
contents are a food source for parasitic eyelash mites. Proliferation of
Demodex mites increases the irritation and inflammation of the eyelids.
Blepharitis is considered as precursor of most of the eye diseases such as dry
eye disease and meibomian glands dysfunction (MGD) 1.
Dry eye syndrome which
is also known as kerato-conjunctivitis-sicca (KCS) is defined as a tear film
disorder due to aqueous tear deficiency or excessive evaporation resulting in
ocular discomfort, visual disturbance, and tear film instability 2. A healthy
tear film is required for the proper functioning of eye the meibomian
secretions and tears are constantly produce to bathe, nourish, and protect the
eye surface. The meibomian glands are present at the upper and lower eyelids.
These glands serve the function of oils secretion onto the surface of the eye.
These oils help keep the tears from evaporating instantaneously. If meibomian glands
dysfunctions it causes dryness of the eye and eyelid inflammation. The oil
glands become block with thickened secretions. Chronically clogged glands
eventually become unable to secrete oil that results in permanent changes in
the tear film and dry eyes. Blepharitis also
causes tears gland(lacrimal glands) margin become inflamed which
degrades the quantity and quality of tears, which causes more bacteria production
in biofilm and when the lacrimal glands fail to produce sufficient tears, dry
eye results3 4.
Dryness of the eye can
also be causes due to environmental, hormonal, physiological, contact lens wear
and pathological causes. Dry eye syndrome is generally recognized as a disruption
of the Lacrimal Functional Unit (LFU), an integrated system comprising the lacrimal glands, ocular
surface (cornea, conjunctiva and meibomian glands) and lids, and the sensory
and motor nerves that connect them. The early methods of treatment involved
lubricating drops, gels or ointments, Anti-inflammatories. These methods were
not long lasting and still there is no permanent cure of this disease. Treatments
for dry eye syndrome help to control the symptoms, but there is no permanent
Research work has been
going on to understand the causes symptoms and effects of this disease in order
to treat dry eye syndrome it is important to fully understand the eye structure
and what leads to dryness in the eye.