EYE DISEASES OR DISORDERS – Presbyopia and Blepharitis (Etiology and Management)
EYE DISEASES OR DISORDERS – Presbyopia and Blepharitis (Etiology and Management)
PRESBYOPIA
Presbyopia is not an error of refraction but a condition of age – related physiological anomaly of accommodation, leading to failing vision for near. The amplitude of accommodation gradually diminishes throughout life. Near vision difficulty starts about the age of 40 years, because of less flexible lens resulting in loss of accommodation. The neuromuscular mechanism of accommodation is not at fault. But on accommodation the lens fails to have the desired convexity.
ETIOLOGY
Decrease in the elasticity and plasticity of the lens with age.
Age – related decrease in the power of cilliary muscle
Causes of premature presbyopia
Hypermetropia
Primary open-angle glaucoma
Premature sclerosis of the lens
Excessive close work
MANAGEMENT
Presbyopia is treated by prescribing convex spherical lens, which added to the glasses, if any, for the distant vision in the following manner:
At the age of 40 years – reading correction is +1D
At the age of 45 years – reading correction is +1.5D
At the age of 50 years – reading correction is +2D
At the age of 55 years – reading correction is +2.5D
Surgical techniques under trial are monovision LASIK, bifocal or multifocal or accommodating IOL, anterior cilliary sclerotomy, and conductive keratoplasty.
DISEASES OF EYELID
BLEPHARITIS
Blepharitis is a chronic bilateral inflammatory reaction of the eyelid margins. It can be anatomically divided into anterior blepharitis which primarily affects the lashes and posterior blepharitis which involves the meibomian glands.
Anterior Blepharitis
Anterior blepharitis is broadly divided into staphylococcal blepharitis and seborrhoeic blepharitis
Staphylococcal blepharitis: it is usually ulcerative and is more serious due to the involvement of the base of hair follicles. Permanent scarring can result
Seborrhoeic blepharitis: Hyperemia and greasy appearance to anterior lid margin with lashes stuck together. Soft scaling occurs along length of lash
Posterior Blepharitis
Meibomian seborrhea: Meibomian gland orifices (lining the lid margin) are covered with small oil globules. Pressing the tarsus (firm bit within the lid) results in copious expression of meibomian
Meibomianitis: Inflammation of the meibomian glands which may be obstructed
CLINICAL MANIFESTATIONS
MANAGEMENT
Lid hygiene: This is the mainstay of treatment and may be sufficient to control simple low grade blepharitis. Lid hygiene should be carried out twice a day in the acute phase and once daily at other times. There are three main aspects to this:
Antibiotic ointment: Chloramphenicol ointment is prescribed 1-4 times per day to lid margin. Teach patient to scrub eyelid margin with cotton swab to remove flaking and then apply ointment with cotton swab
Systemic antibiotics: Meibomitis responds better to systemic antibiotics over a minimum of six weeks (12 weeks provides a prolonged effect). Option include: