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Senile cataract


Senile Cataract
Author: Vicente Victor D Ocampo, Jr, MD; Chief Editor: Hampton Roy, Sr, MD
Senile cataract is an age-related, vision-impairing disease characterized by gradual, progressive thickening of the lens of the eye. It is one of the world’s leading causes of blindness.

Signs and symptoms

A patient with senile cataract often presents with a history of gradual, progressive deterioration and disturbance in vision. Characteristics of senile cataract include the following:

Decreased visual acuity - The most common complaint of patients with senile cataract
Glare - Can range from a decrease in contrast sensitivity in brightly lit environments or disabling glare during the day to glare with oncoming headlights at night
Myopic shift - The progression of cataracts frequently increases the diopteric power of the lens, resulting in a mild to moderate degree of myopia or myopic shift
Monocular diplopia - At times, the nuclear changes are concentrated in the inner layers of the lens, resulting in a refractile area in the center of the lens; this may lead to monocular diplopia that is not corrected with spectacles, prisms, or contact lenses
See Clinical Presentation for more detail.

Diagnosis

A complete ocular examination must be performed, beginning with visual acuity for near and far distances. When the patient complains of glare, visual acuity should be tested in a brightly lit room. Contrast sensitivity also must be checked, especially if the history points to a possible problem.

Diagnosis can also include the following:

Examination of the ocular adnexa and intraocular structures - May provide clues to the patient's disease and eventual visual prognosis
Swinging flashlight test - Detects a Marcus Gunn pupil or a relative afferent pupillary defect (RAPD) indicative of optic nerve lesions or diffuse macular involvement
Slit lamp examination - Should concentrate on the evaluation not only of lens opacity but also of other ocular structures as well (eg, conjunctiva, cornea, iris, anterior chamber)
Examination of nuclear size and brunescence - After dilation, nuclear size and brunescence as indicators of cataract density can be determined prior to phacoemulsification surgery
Direct and indirect ophthalmoscopy - To evaluate the integrity of the posterior pole
Ocular imaging studies such as ultrasonography, computed tomography (CT) scanning, or magnetic resonance imaging (MRI) are requested when a posterior pole pathology is suspected and an adequate view of the back of the eye is obscured by a dense cataract.

Staging

Clinical staging of senile cataract is based largely on the visual acuity of the patient, as follows:

Mature cataract - Patient cannot read better than 20/200 on the visual acuity chart
Immature cataract - Patient can distinguish letters at lines better than 20/200
Incipient cataract - Patient can still read at 20/20 but possesses a lens opacity as confirmed by slit lamp examination
See Workup for more detail.

Management

Lens extraction is the definitive treatment for senile cataract. It can be accomplished via the following procedures:

Intracapsular cataract extraction (ICCE) - Involves extraction of the entire lens, including the posterior capsule; the many postoperative complications associated with this procedure has led to a decline in its use
Extracapsular cataract extraction (ECCE) - Involves the removal of the lens nucleus through an opening in the anterior capsule, with retention of the integrity of the posterior capsule
Phacoemulsification - Also involves extraction of the lens nucleus through an opening in the anterior capsule; an ultrasonically driven needle is used to fragment the nucleus of the cataract; the lens substrate is then aspirated through a needle port in a process termed phacoemulsification
Intraocular lens (IOL) implantation is used in combination with each of these techniques, although ECCE and phacoemulsification allow for better placement of the IOL than does ICCE.

See Treatment and Medication for more detail.

Background
Senile cataract is a vision-impairing disease characterized by gradual, progressive thickening of the lens. It is one of the leading causes of blindness in the world today. This is unfortunate, considering that the visual morbidity brought about by age-related cataract is reversible. As such, early detection, close monitoring, and timely surgical intervention must be observed in the management of senile cataracts. The succeeding section is a general overview of senile cataract and its management.

Pathophysiology
The pathophysiology behind senile cataracts is complex and yet to be fully understood. In all probability, its pathogenesis is multifactorial involving complex interactions between various physiologic processes. As the lens ages, its weight and thickness increases while its accommodative power decreases. As the new cortical layers are added in a concentric pattern, the central nucleus is compressed and hardened in a process called nuclear sclerosis.

Multiple mechanisms contribute to the progressive loss of transparency of the lens. The lens epithelium is believed to undergo age-related changes, particularly a decrease in lens epithelial cell density and an aberrant differentiation of lens fiber cells. Although the epithelium of cataractous lenses experiences a low rate of apoptotic death, which is unlikely to cause a significant decrease in cell density, the accumulation of small scale epithelial losses may consequently result in an alteration of lens fiber formation and homeostasis, ultimately leading to loss of lens transparency. Furthermore, as the lens ages, a reduction in the rate at which water and, perhaps, water-soluble low-molecular weight metabolites can enter the cells of the lens nucleus via the epithelium and cortex occurs with a subsequent decrease in the rate of transport of water, nutrients, and antioxidants.

Consequently, progressive oxidative damage to the lens with aging takes place, leading to senile cataract development. Various studies showing an increase in products of oxidation (eg, oxidized glutathione) and a decrease in antioxidant vitamins and the enzyme superoxide dismutase underscore the important role of oxidative processes in cataractogenesis.

Another mechanism involved is the conversion of soluble low-molecular weight cytoplasmic lens proteins to soluble high molecular weight aggregates, insoluble phases, and insoluble membrane-protein matrices. The resulting protein changes cause abrupt fluctuations in the refractive index of the lens, scatter light rays, and reduce transparency. Other areas being investigated include the role of nutrition in cataract development, particularly the involvement of glucose and trace minerals and vitamins.

Senile cataract can be classified into 3 main types: nuclear cataract, cortical cataract, and posterior subcapsular cataract. Nuclear cataracts result from excessive nuclear sclerosis and yellowing, with consequent formation of a central lenticular opacity. In some instances, the nucleus can become very opaque and brown, termed a brunescent nuclear cataract. Changes in the ionic composition of the lens cortex and the eventual change in hydration of the lens fibers produce a cortical cataract. Formation of granular and plaquelike opacities in the posterior subcapsular cortex often heralds the formation of posterior subcapsular cataracts.

Frequency
United States

In the Framingham Eye Study from 1973-1975, senile cataract was seen in 15.5% of the 2477 patients examined. The overall rates of senile cataract in general, and of its 3 main types (ie, nuclear, cortical, posterior subcapsular), rapidly increased with age; for the oldest age group (≥75 y), nuclear, cortical, and posterior subcapsular cataracts were found in 65.5%, 27.7%, and 19.7% of the study population, respectively. Nuclear opacities were the most commonly seen lens change.

An updated study by the Wilmer Eye Institute in 2004 noted that approximately 20.5 million (17.2%) Americans older than 40 years had a cataract in either eye and 6.1 million (5.1%) were pseudophakic/aphakic.[1] These numbers are expected to rise to 30.1 million cataracts and 9.5 million cases with pseudophakia/aphakia by 2020.

Prevent Blindness America currently estimates that more than 22 million Americans aged 40 years and older have a cataract. An average of 3 million Americans undergo cataract surgery every year, with a 95% success rate of obtaining a best corrected vision of 20/20-20/40.

International

Senile cataract continues to be the main cause of visual impairment and blindness in the world. In recent studies done in China,[2, 3] Canada,[4] Japan,[5] Denmark,[6] Argentina,[7] and India,[8] cataract was identified as the leading cause of visual impairment and blindness, with statistics ranging from 33.3% (Denmark) to as high as 82.6% (India). Published data estimate that 1.2% of the entire population of Africa is blind, with cataract causing 36% of this blindness. In a survey conducted in 3 districts in the Punjab plains, the overall rates of occurrence of senile cataract was 15.3% among 1269 persons examined who were aged 30 years and older and 4.3% for all ages. This increased markedly to 67% for ages 70 years and older. An analysis of blind registration forms in the west of Scotland showed senile cataract as 1 of the 4 leading causes of blindness.

Mortality/Morbidity
Most morbidity associated with senile cataracts occurs postoperatively and is discussed in further detail later. Failure to treat a developing cataract surgically may lead to devastating consequences, such as lens swelling and intumescence, secondary glaucoma, and, eventually, blindness.

While the risk of dying as a result of cataract extraction is almost negligible, studies have shown an increased risk of mortality in patients who underwent surgery. In a comparison of 167 patients aged 50 years or older who underwent cataract extraction at the New England Medical Center in a period of 1 year to 824 patients who elected 1 of 6 other surgical procedures, it was found that the former had almost twice the mortality of the latter. Further analysis showed no significant correlation between diabetes and increased mortality. In a similar 5-year mortality analysis, patients with cataracts who were younger than 75 years had significantly higher age-specific rates of mortality than would be expected from US life tables.

These data imply an association between senile cataracts and increased mortality. Meddings et al suggest that senile cataract may be a marker of generalized tissue aging.[9] Hirsch and Schwartz who proposed the concept that senile cataracts reflect systemic phenomena rather than only a localized ocular disease share this view.[10]

Race

Although race has been suggested as a possible risk factor for senile cataract, scarce literature exists to prove this theory. However, it has been observed that unoperated cataracts account for a higher percentage of blindness among blacks compared to whites.

S*x

Studies on the prevalence of senile cataract between males and females have yielded contrasting results.

In the Framingham Eye Study from 1973-75, females had a higher prevalence than males in both lens changes (63% vs 54.1%) and senile cataract (17.1% vs 13.2%).

Sperduto and Hiller noted that each of the 3 types of senile lens opacities was found more often in women than in men.[11] In a separate investigation by Nishikori and Yamomoto, the male-to-female ratio was 1:8 with a female predominance in patients older than 65 years who were operated on for senile cataract.[12]

In a hospital-based, case-control study of senile cataract conducted in Japan, it was observed that an increased risk of cataract was found in males who were presently spending 7 hours or more outdoors and in females with 4 or fewer remaining teeth. However, in another analysis by Martinez et al, no sexual difference was noted in the prevalence of senile cataract.[13]

Age

Age is an important risk factor for senile cataract. As a person ages, the chance of developing a senile cataract increases. In the Framingham Eye Study from 1973-1975, the number of total and new cases of senile cataract rose dramatically from 23.0 cases per 100,000 and 3.5 cases per 100,000, respectively, in persons aged 45-64 years to 492.2 cases per 100,000 and 40.8 cases per 100,000 in persons aged 85 years and older

Megalocornea

Author: Mark Ventocilla, OD, FAAO;

Chief Editor: Hampton Roy, Sr, MD
Introduction:

Megalocornea is a rare nonprogressive enlargement of the cornea to 13 mm or greater; in the setting of normal intraocular pressure. The cornea and limbus are enlarged, but the cornea itself is histologically normal and of normal thickness. Megalocornea is usually seen as an isolated finding, known as simple isolated megalocornea. It may be associated with other ocular and systemic findings, including megophthalmos anterior and/ or dysgenesis of the iris, lens, and ciliary body.

Pathophysiology

Megalocornea is a developmental anomaly of unknown etiology. Postulated mechanisms of development include a defect in formation of the optic cup in which the anterior tips of the cup fail to fuse, allowing more space for the developing cornea. This is considered a primary overgrowth of the cornea, producing a normal endothelial cell density. In congenital glaucoma, the main differential diagnosis, the cell density is low due to distention of the cornea from elevated intraocular pressure. The cornea does not reach its full adult size until age 12 months; thus, a definitive diagnosis of megalocornea cannot be ruled out until after this time.

Epidemiology
Frequency

United States

No data are available.

International

No data are available.

Mortality/Morbidity

Morbidity and mortality can be secondary to the many systemic conditions found in association with megalocornea. See Special Concerns.

Ocular morbidity is associated with anterior megalophthalmos. An enlarged ciliary ring causes zonular stretching, leading to phacodonesis, ectopia lentis, iridodonesis, iris stromal hypoplasia and transillumination defects, Krukenberg spindles, and trabecular meshwork pigmentation. Other findings are posterior embryotoxon, Rieger anomaly, goniodysgenesis, and cataracts. Goniodysgenesis and pigment dispersion can contribute to glaucoma.

S*x

Males account for 90% of cases because X-linked recessive inheritance is most common.

Age

Megalocornea is present from birth.

Clinical Presentation



RELATED REFERENCE TOPICS
Wolf-Hirschhorn Syndrome
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Megalocornea

Treatment
Medical Care
Medical care for patients with megalocornea includes correction of refractive error and thorough evaluation for findings of anterior megalophthalmos. Also, routine examination for the development of cataracts and glaucoma is necessary.

Surgical Care
Surgical amelioration of glaucoma and cataract is performed when necessary.

Cataract is common with megalocornea, and the cataract surgery is difficult. The zonules supporting the lens capsule surrounding the cataract are often weak. Weakened zonules make it more difficult to support an artificial intraocular lens (IOL). This leads to increased surgical complications, such as vitreous loss and loss of lens material to the back of the eye during cataract surgery.[1, 2, 3]

The large size of the anterior segment makes IOL selection difficult as standard IOLs are too small. A standard lens will often not work. Oetting and Newsom at the University of Iowa reported on the use of a special IOL called the Artisan lens (see the image below) that clips onto the iris.[4]

Megalocornea patient with Artisan lens.
Megalocornea patient with Artisan lens.
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Because this IOL clips onto the iris rather than fitting into the angle, it allows for a safe and stable placement, even with the large anterior segment. Basti and colleagues reported using suture based iris fixation to allow placement of a standard IOL in these large eyes.[5]

Consultations
Pediatric developmental specialist consultation is always indicated to evaluate for the many associated systemic conditions. These include albinism, Down syndrome, Marfan syndrome, Alport syndrome, craniosynostosis, and many others.

Follow-up



RELATED REFERENCE TOPICS
Wolf-Hirschhorn Syndrome
ABOUT
About Medscape
Privacy Policy
Terms of Use
Help Center
MEMBERSHIP
Become a Member
Email Newsletters
Manage My Account
APPS
Medscape
MedPulse News
CME & Education
Business of Medicine
WebMD NETWORK
WebMD
MedicineNet
eMedicineHealth
RxList
WebMD Corporate
EDITIONS
English
Français
Deutsch
All material on this website is protected by copyright, Copyright © 1994-2016 by WebMD LLC. This website also contains material copyrighted by 3rd parties.

New vaccination schedule , will be helpfull all

Blepharitis is a common eyelid inflammation that sometimes is associated with a bacterial eye infection, symptoms of dry eyes or certain types of skin conditions such as acne rosacea.

Blepharitis has two basic forms:

Anterior blepharitis, affecting the outside front of the eyelid where eyelashes are attached.
Posterior blepharitis, linked to dysfunction of meibomian glands within the eyelids that secrete oils to help lubricate the eye.
It's common to have a mixture of both anterior and posterior forms of blepharitis at the same time, but in different degrees of severity.

Although eye doctors commonly diagnose blepharitis, it can be difficult to find permanent relief of the symptoms that can include burning, flaking, crusting, tearing, irritation, itching, redness in eyelid margins and a foreign body sensation.

Man rubs irritated eye with tissue.
Blepharitis can cause inflamed eyelids, eye burning and dryness.
Treatment for Blepharitis

If you are diagnosed with chronic blepharitis, your eye doctor will likely recommend an ongoing regimen of eyelid hygiene (see sidebar) that can include commercially developed, over-the-counter lid scrubs or other recommended cleansing agents. Eyelid hygiene is the cornerstone of treatment for most cases of blepharitis.

Besides a program of eyelid hygiene, the severity of the blepharitis and related symptoms may require supplemental treatment with topical and oral medicine.

In some cases of posterior blepharitis, eye doctors recommend nutritional supplementation with omega-3 fatty acids, such as flaxseed oil, to aid healthy function of meibomian glands that provide essential lubrication for eye and eyelid comfort.

treatment of bacterial conjuctivities:
1)antibiotic eye drop -1 drop both eyes 2 hourly,
2)antibiotic eye ointment - at night in affected eye,3) maintain the ocular hygiene

পানির উপকারিতা

signs on eye for various diseases

male reproductive system