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tight and act as a blockade for tear uid, trapping tears between the oiled edge and eyeball. There are approximately 50 glands on the upper eyelid and 25 glands on the lower.
Dysfunctional meibomian glands often cause dry eyes, one of the more common eye conditions. They may also cause blepharitis, an in ammation of the eyelids, as the dry eyeball rubs off small pieces of skin from the eyelid, which may get infected. In ammation of the meibomian glands (also known as meibomitis, meibomian gland dysfunction or posterior blepharitis) causes the glands to be obstructed by thick secretions; the resulting swelling is termed a chalazion. Besides leading to dry eyes, the obstructions can be degraded by bacterial lipases (water insoluble lipids or fats), resulting in the formation of free fatty acids, which irritate the eyes and sometimes cause punctate keratopathy. Typical treatments for MGD may include, depending on speci cs of the condition: warm compresses (to liquefy any secretions that have solidi ed and are clogging the glands), lid scrubs, oral antibiotics (such as doxycycline) or topical antibiotic ointments, and Omega 3 supplementation. Contact lens wear should be stopped until these conditions/symptoms improve.
Corneal diseases and conditions can cause redness, watery eyes, pain, reduced vision or a halo effect. The cornea is the clear domeshaped “window” at the front of the eye. It helps to refract and focus light that enters the eye. Disease, infection, injury, toxic agents and other things can harm the cornea. Advise patients to always wear eye protection for any sport activities, when working with any equipment, when using caustic cleaning chemicals or when doing yard work.
Cataract is the clouding of the crystalline lens. Common symptoms include blurry vision, glare in sunlight, halos at night around streetlights or car lights, colored objects losing their original tone and an increase in myopia (nearsightedness from extreme attening of the crystalline lens). Cataracts do not affect contact lens wear.
Glaucoma damages the optic nerve due to increased pressure within the eyeball due to inadequate drainage or overproduction of uid inside the eye. The optic nerve relays electrochemical signals
to the brain, without which we cannot see. It can result in blindness if untreated in the early stages of the disease. In early glaucoma, patients may not have any symptoms. Therefore, the condition is often neglected. Early diagnosis and treatment can help prevent blindness. Glaucoma is treatable but not curable. Many can continue to wear contacts with glaucoma depending on their eye doctor’s recommendation.
Age-related macular degeneration (AMD)
is a major cause of visual impairment and legal blindness in older adults. Macular degeneration results in central vision loss, which can make it dif cult or impossible to read, see faces, drive and even walking becomes more hazardous, all of which compromise one’s independence. Peripheral vision remains but is very limiting.
Behind the retina is the choroid, which contains the blood supply to the macula (the central retina and the area of highest resolution vision). In the dry (non-exudative) form, cellular debris called drusen accumulate between the retina and the choroid. This interferes with the blood supply to the retina cells and can ultimately cause cell death. These pockets of cellular debris separate the retina from normal blood supply inhibiting normal metabolism of waste removal as well as the delivery of nutrients to the photoreceptor cells that are essential for sight. Blindness can occur rapidly with retinal detachment in the wet (exudative) form of AMD. Exudative AMD can result in neovascularization and is more severe, because the blood vessels grow up from the choroid into the retina and swell and leak. The retina can become scarred and may become detached. Exudative AMD can be treated with laser coagulation and with injections of medication that stops and sometimes reverses the growth of leaky unstable blood vessels.
Diabetic retinopathy: Diabetes mellitus (DM) can cause diabetic retinopathy (DR) and ultimately diabetic macula edema (DME), both of which can advance to severe vision loss and even blindness. Prevent Blindness lists the following stages:
Mild nonproliferative retinopathy: At this stage, micro aneurysms occur. They are small areas of balloon-like swelling in the retina’s tiny blood vessels.
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