CHAPTER I
DISCUSSION
1.1 Definition Of Cataracts
A cataract is a clouding that develops in the crystalline lens of the eye or in its envelope, varying in degree from slight to complete opacity and obstructing the passage of light. Early in the development of age-related cataract, the power of the lens may be increased, causing near-sightedness (myopia), and the gradual yellowing and opacification of the lens may reduce the perception of blue colours. Cataracts typically progress slowly to cause vision loss, and are potentially blinding if untreated. The condition usually affects both eyes, but almost always one eye is affected earlier than the other.
A senile cataract, occurring in the elderly, is characterized by an initial opacity in the lens, subsequent swelling of the lens and final shrinkage with complete loss of transparency. Moreover, with time the cataract cortex liquefies to form a milky white fluid in a Morgagnian cataract, which can cause severe inflammation if the lens capsule ruptures and leaks. Untreated, the cataract can cause phacomorphic glaucoma. Very advanced cataracts with weak zonules are liable to dislocation anteriorly or posteriorly. Such spontaneous posterior dislocations (akin to the historical surgical procedure of couching) in ancient times were regarded as a blessing from the heavens, because some perception of light was restored in the cataractous patients.
Some children develop cataracts, called congenital cataracts, before or just after birth, but these are usually dealt with in a different way to cataracts in adults.
1.2 Etiology Of Cataracts
Cataracts develop for a variety of reasons, including long-term exposure to ultraviolet light, exposure to radiation, secondary effects of diseases such as diabetes, hypertension and advanced age, or trauma (possibly much earlier); they are usually a result of denaturation of lens protein.
Genetic factors are often a cause of congenital cataracts, and positive family history may also play a role in predisposing someone to cataracts at an earlier age, a phenomenon of "anticipation" in presenile cataracts. Cataracts may also be produced by eye injury or physical trauma. A study among Icelandair pilots showed commercial airline pilots are three times more likely to develop cataracts than people with nonflying jobs. This is thought to be caused by excessive exposure to radiation coming from outer space .Supporting this theory is the report that 33 of the 36 Apollo astronauts involved in the nine Apollo missions to leave Earth orbit have developed early stage cataracts that have been shown to be caused by radiation exposure to cosmic rays during their trip. At least 39 former astronauts have developed cataracts; 36 of those were involved in high-radiation missions such as the Apollo missions. Cataracts are also unusually common in persons exposed to infrared radiation, such as glassblowers, who suffer from "exfoliation syndrome". Exposure to microwave radiation can cause cataracts. Atopic or allergic conditions are also known to quicken the progression of cataracts, especially in children.[26] Cataracts can also be caused by iodine deficiency..
Cataracts may be partial or complete, stationary or progressive, hard or soft. Some drugs can induce cataract development, such as corticosteroids and Seroquel.
1.3 Classification and epidemiology of Cataract
1.Congenital, is a cataract that occurred since the baby is born and develops in the first year of his life. This type of cataract is very rare.
2. Traumatic, is a cataract that occurs because of an accident on the eyes.
3. Secondary cataracts are caused by the consumption of drugs such as prednisone and corticosteroids, as well as diabetics. Cataract affects 10 times more commonly by people with diabetes than the general population.
3. Secondary cataracts are caused by the consumption of drugs such as prednisone and corticosteroids, as well as diabetics. Cataract affects 10 times more commonly by people with diabetes than the general population.
4. Age-related cataract is the most common type of cataract. Based on its location, there are 3 types of cataract, ie, nuclear sclerosis, cortical, and posterior subcapsular. Nuclear sclerosis is a lens changes gradually so that it becomes hard and yellowish. The view is much more affected than near vision (sight reading), sight reading may be even better. Patients also have difficulty distinguishing colors, especially colors birru. Type of cortical cataract occurs when the fibers of the lens becomes cloudy, it can cause glare especially when driving at night. Is the occurrence of posterior subcapsular opacities in the lens rear side. Cataract causes glare, blurred vision in bright light conditions, as well as decreased reading vision.
- Classified by opacities, cataract can be classified by using Lens Opacities Classification System III (LOCS III: Nuclear NC1-5, Cortical C1-5 and Posterior P1-5. By application planning in procedures of phacoemulsification, LCOS III can be converted in newer cataract grading systems. Gede Pardianto (2009) introduced Optical Biometry Based Cataract Grading System (OBBCGS) that is helpful in cataract grading due to phacoemulsification planning. LOCS III's NC0, C0 and P0 can be converted as OBBCGS' no cataract (NC), LOCS III's NC1-3, C1-3, P1-4 can be converted to OBBCGS' Optical Biometry Examined Cataract (OBEC) and LOCS III's NC4-5, C4-5, P4-5 can be converted to OBBCGS's Optical Biometry Unexamined Cataract (OBUC); that need examination by Applanation Ultrasound Biometry.
- Classified by location of opacity within lens structure (however, mixed morphology is quite commonly seen, e.g. PSC with nuclear changes and cortical spokes of cataract)
· Anterior cortical cataract
· Anterior polar cataract
· Anterior subcapsular cataract
· Nuclear cataract—grading correlates with hardness and difficulty of surgical removal
1: Grey
2: Yellow
3: Amber
4: Brown/black (Note: "black cataract" translated in some languages (like Hindi) refers to glaucoma, not the color of the lens nucleus)
· Posterior cortical cataract
· Posterior polar cataract (importance lies in higher risk of complication—posterior capsular tears during surgery)
· Posterior subcapsular cataract (PSC) (clinically common)
· After-cataract: posterior capsular opacification (PCO) subsequent to a successful extracapsular cataract surgery (usually within three months to two years) with or without IOL implantation. Requires a quick and painless office procedure with Nd:YAG laser capsulotomy to restore optical clarity.
Epidemiology
Age-related cataract is responsible for 48% of world blindness, which represents about 18 million people, according to the World Health Organization (WHO). In many countries, surgical services are inadequate, and cataracts remain the leading cause of blindness. As populations age, the number of people with cataracts is growing. Cataracts are also an important cause of low vision in both developed and developing countries. Even where surgical services are available, low vision associated with cataracts may still be prevalent, as a result of long waits for operations and barriers to surgical uptake, such as cost, lack of information and transportation problems.
In the United States, age-related lenticular changes have been reported in 42% of those between the ages of 52 and 64, 60% of those between the ages 65 and 74, and 91% of those between the ages of 75 and 85.
The increase in ultraviolet radiation resulting from depletion of the ozone layer is expected to increase the incidence of cataracts.
1.4 Nursing Treatment
Surgical
The operation to remove cataracts can be performed at any stage of their development. There is no longer a reason to wait until a cataract is "ripe" before removing it. However, because any surgery involves some risk, it is usually worth waiting until there is some change in vision before removing the cataract.
The most effective and common treatment is to make an incision (capsulotomy) into the capsule of the cloudy lens to surgically remove it. Two types of eye surgery can be used to remove cataracts: extracapsular cataract extraction (ECCE) and intracapsular cataract extraction (ICCE). ECCE surgery consists of removing the lens, but leaving the majority of the lens capsule intact. High frequency sound waves (phacoemulsification) are sometimes used to break up the lens before extraction. Intra-capsular (ICCE) surgery involves removing the entire lens of the eye, including the lens capsule, but it is rarely performed in modern practice.
In either extracapsular surgery or intracapsular surgery, the cataractous lens is removed and replaced with a plastic lens (an intraocular lens implant) which stays in the eye permanently.
Cataract operations are usually performed using a local anaesthetic, and the patient is allowed to go home the same day. Recent improvements in intraocular technology now allow cataract patients to choose a multifocal lens to create a visual environment in which they are less dependent on glasses. Such multifocal lenses are flexible and can be controlled using the same eye muscles used to control the natural lens. Under some medical systems, multifocal lenses cost extra. Traditional intraocular lenses are monofocal.
Complications are possible after cataract surgery, including endophthalmitis, posterior capsular opacification and retinal detachment.
1.5 Prevention
Although cataracts have no scientifically proven prevention, wearing ultraviolet-protecting sunglasses may slow the development of cataracts. Regular intake of antioxidants (such as vitamins A, C and E) is theoretically helpful, but taking them as a supplement has not been shown to have a benefit. The less well-known antioxidant N-acetylcarnosine has been shown in randomized controlled clinical trials to treat cataracts, and can be expected to prevent their formation by similar mechanisms. N-acetylcarnosine is a proposed treatment for other ocular disorders that are instigated, or exacerbated, by oxidative stress, including glaucoma, retinal degeneration, corneal disorders, and ocular inflammation.
CHAPTER II CLOSING
2.1 Conclusion
A cataract is a clouding that develops in the crystalline lens of the eye or in its envelope, varying in degree from slight to complete opacity and obstructing the passage of light.
Cataracts develop for a variety of reasons, including long-term exposure to ultraviolet light, exposure to radiation, secondary effects of diseases such as diabetes, hypertension and advanced age, or trauma (possibly much earlier); they are usually a result of denaturation of lens protein.
References
Smeltzer, Suzanne C. 2001. Buku Ajar Keperawatan Medikal Bedah Brunner & Suddarth. Alih bahasa : Agung Waluyo. Jakarta. EGC.
Tidak ada komentar:
Posting Komentar