Glaucoma is an eye disorder in which damage to the optic nerve leads to progressive, irreversible vision loss. It causes complete blindness if untreated.
Glaucoma is the second leading cause of blindness worldwide and is six to eight times more common in African-Americans. It is a neurodegenerative disease characterized by the slow degeneration of retinal ganglion cells and their axons. The
leading risk factor for the loss of the retinal ganglion cells and development of the optic nerve atrophy is the elevated intraocular pressure.
Glaucoma can be divided roughly into two main categories: „open angle” and „closed angle” glaucoma.
Open angle glaucoma (sometimes called chronic glaucoma) is the most common type of this eye disorder, affecting 70-80 percent of patients. Open angle glaucoma typically occurs in patients over the age of 50, and the risk increases with age. People with open angle glaucoma experience a gradual blockage of aqueous outflow despite a seemingly open space (chamber angle) in the front of the eye. As the eye ages, the drainage system can become clogged or the eye over-produces aqueous fluid, either of which causes pressure inside the eye to build to abnormal levels.
In closed angle glaucoma, the drainage canals in the eyes become blocked or covered because the angle between the iris and cornea is too narrow. The blockage can occur suddenly or slowly. If the eye pressure rises rapidly, people typically notice an abrupt onset of severe eye pain and headache, blurred vision, redness, rainbow-colored halos around lights, and sudden loss of vision as well. They may also suffer from nausea and vomiting.
Although the optic nerve damage and visual loss from glaucoma usually cannot be reversed, the disease can gene-rally be controlled. Treatment can make the intraocular pressure normal and, therefore, prevent or retard further nerve damage and visual loss. Medical intervention may involve the use of eye drops, oral drugs, laser, or surgery.
There are five different groups of antiglaucoma medications: parasympathomimetics (pilocarpine), beta-adrenergic receptor antagonists (timolol, levobunolol), carbonic anhydrase inhibitors (dorzolamide, brinzolamide), alpha2-adrenergic agonists (brimonidine), and prostaglandin analogs (latanoprost, bimatoprost). The possible neuroprotective effects of various topical and systemic medications are also being investigated.
EXERCISE: CHOOSE TRUE OR FALSE.
1. The main risk factor for glaucoma is raised pressure within the eyeball.
2. The older you are, the higher risk for glaucoma you have.
3. In open angle glaucoma the anterior chamber angle is open.
4. Closed angle glaucoma is not associated with pain.
5. Beta-blockers are used in glaucoma treatment.
• glaucoma [glɔˈkoʊmə] – jaskra
• irreversible [ɪrɪˈvɜrsəbəl] – nieodwracalny
• retinal ganglion cell [ˈrɛtnəl ˈgæŋgliən sɛl] – komórka zwojowa siatkówki
• intraocular [ɪntrəˈɒkyələr] – śródgałkowy
• open angle glaucoma – jaskra otwartego kąta (z otwartym kątem przesączania)
• closed angle glaucoma – jaskra zamkniętego kąta (z zamkniętym kątem przesączania)
• aqueous outflow [ˈækwiəs ˈaʊtfloʊ] – wypływ płynu
• chamber angle [ˈtʃeɪmbər ˈæŋgəl] – kąt komory
• drainage [ˈdreɪnɪdʒ] – drenaż
• clogged [klɒgd] – zatkany
• iris [ˈaɪrɪs] – tęczówka
• cornea [ˈkɔrniə] – rogówka
• abrupt [əˈbrʌpt] – nagły, gwałtowny, ostry
• halo [ˈheɪloʊ] – aureola, otoczka
• to retard [tə rɪˈtɑrd] – opóźniać
• parasympathomimetic [ˈpɑrɑsɪmpəθoʊmɪˈmɛtɪk] – parasympatomimetyk
Correct answers: true, true, true, false, true