Ophtamological lexicon

Blepharitis is an inflamation that usually affects both eyes along the edges of the eyelids. It commonly occurs when tiny oil glands near the base of the eyelashes become clogged, causing irritation and redness

There are 2 clinical forms that can be desiphered:

– Prior damages on the skin side of the palpebral edge (free edge and eyelashes) such as staphylococcal seborrheic blepharitis

– Posterior damage,also called “meibomian dysfunction”, concerning the mucous side of the palpebral edge. Meibomian dysfunction is characterized by a meibum that is too viscous to naturally exit the meibomian glands when blinking. The obstruction of the orifices of these glands disrupts the lipid layer of the tear film which leads dry eye problem. to dry eyes by hyperevaporation of the tears.

Symptoms are common for both clinical forms – redness, swollen palpebral edge, secretions and crusts. In first type damage to the eyelashes is predominant (short, brittle eyelashes or even loss of eyelashes). In latter one, thick secretions, dry eye problem. and often recurrent chalazia can be observed in children.

Partial or total clouding of the lens that interferes with the passage of light. In most cases cataracts are related to age.

Age-related cataracts are the leading cause of blindness worldwide (48%), being resposible for 18 million people.(*Data by WHO)

It affects more than 60% of people over 85 years old in France.

State of a person deprived of the vision.

The mucous membrane that covers the front of the eye and lines the inside of the eyelids

Thin and transparent membrane on the surface of the eye covering the iris and pupil. It constitutes the first lens of the ocular optical system.

Intermediate layer of the tear film consisting of water (98%), mucins and anti-inflammatory proteins. It is secreted by the lacrimal glands and provides defense and nutrition functions for the ocular surface.

Basal layer of the tear film the tear film made up of mucins that make the ocular surface hydrophilic. It allows the tear film to adhere the tear film to the ocular surface and contributes to its stability.

Internal lens of the eye which ensures the sharpness of the images by modifying its curvature. If the lens loses its elasticity, it is responsible for presbyopia and if it becomes cloudy, it is responsible for cataracts..

Eye disease which may appear with age. It affects the center of the retina,called the macula, and causes loss of central vision without affecting peripheral vision.

AMD is the third leading cause of visual impairment in the world and accounts for 8.7% of the causes of blindness.It is the leading cause of visual impairment in industrialized countries.

The main risk factor is age. Other possible risk factors are smoking, genetic influence, degree of pigmentation (greater risk in case of clear iris), high blood pressure, ultraviolet rays and dietary imbalance. (* Source: WHO)

The tear film provides nutritional functions as well as mechanical, chemical and anti-infectious protection of the ocular surface.

It is made up of 3 layers:

– The mucinic layer

– The aqueous layer

– The lipid layer

The entire lipid layer is essential: its deterioration leads to overevaporation of tears and eventually to dry eye problem..

The Meibomian glands were named by Meibom H. who first described them in 1666. They are located on the free edge of the eyelids and number 30 to 40 for the upper eyelid and 20 to 30 for the lower eyelid.

These glands secrete oil substance, of meibumwhich coats the surface of our eyes and keeps the water component of our tears from evaporating (drying out)

Glands that produce tears.

Visual defect characterized by a clearer vision from afar than near, due to an eye that is too « small » or not powerful enough. As a result, images form behind the retina.

Major cause of dry eye problem. 80% of cases). The lipid layer of the tear film the tear film is altered and no longer performs its anti-evaporative role despite the production of tears in sufficient quantity.

Insufficient production of tears by the lacrimal glands.

The colored tissue at the front of the eye that contains the pupil in the center. The iris helps control the size of the pupil to let more or less light into the eye..

A liposome is a spherical-shaped vesicle that is composed of one or more phospholipid bilayers, which closely resembles the structure of cell membranes..