Katarak

Cataract

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 the eyes, but almost always one eye is affected earlier than the other.

A senile cataract, occurring in the aged, is characterized by an initial opacity in the lens, subsequent swelling of the lens and final shrinkage with complete loss of transparency.^[2] 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.

Cataract derives from the Latin cataracta meaning "waterfall" and the Greek kataraktes and katarrhaktes, from katarassein meaning "to dash down" (kata-, "down"; arassein, "to strike, dash"). As rapidly running water turns white, the term may later have been used metaphorically to describe the similar appearance of mature ocular opacities. In Latin, cataracta had the alternate meaning "portcullis",^[4] so it is also possible that the name came about through the sense of "obstruction". Early Persian physicians called the term nazul-i-ah, or "descent of the water"—vulgarised into waterfall disease or cataract—believing such blindness to be caused by an outpouring of corrupt humour into the eye. In dialect English a cataract is called a pearl, as in "pearl eye" and "pearl-eyed".

Causes

Cataracts develop from 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 pre-senile 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 non-flying jobs. This is thought to be caused by excessive exposure to radiation coming from outer space.^[7] 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.

Cataracts may be partial or complete, stationary or progressive, hard or soft.

Some drugs can induce cataract development, such as corticosteroids^[9] and Ezetimibe and Seroquel.

There are various types of cataracts, e.g. nuclear, cortical, mature, and hypermature. Cataracts are also classified by their location, e.g. posterior (classically due to steroid use) and anterior (common (senile) cataract related to aging).

Symptoms

As a cataract becomes more opaque, clear vision is compromised. A loss of visual acuity is noted. Contrast sensitivity is also lost, so that contours, shadows and color vision are less vivid. Veiling glare can be a problem as light is scattered by the cataract into the eye. A contrast sensitivity test should be performed and if a loss in contrast sensitivity is demonstrated an eye specialist consultation is recommended.

In the developed world, particularly in high-risk groups such as diabetics, it may be advisable to seek medical opinion if a 'halo' is observed around street lights at night, especially if this phenomenon appears to be confined to one eye only.

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 to 64, 60% of those between the ages 65 and 74, and 91% of those between the ages of 75 and 85.

Historical

The earliest records are from the Bible as well as early Hindu records. Early cataract surgery was developed by the Indian surgeon, Sushruta (6th century BCE). The Indian tradition of cataract surgery was performed with a special tool called the Jabamukhi Salaka, a curved needle used to loosen the lens and push the cataract out of the field of vision. The eye would later be soaked with warm butter and then bandaged. Though this method was successful, Sushruta cautioned that it should only be used when necessary. Greek physicians and philosophers traveled to India where these surgeries were performed by physicians. The removal of cataract by surgery was also introduced into China from India.

The first references to cataract and its treatment in Ancient Rome are found in 29 AD in De Medicinae, the work of the Latin encyclopedist Aulus Cornelius Celsus. The Romans were pioneers in the health arena—particularly in the area of eye care.

The Iraqi ophthalmologist Ammar ibn Ali of Mosul performed the first extraction of cataracts through suction. He invented a hollow metallic syringe hypodermic needle, which he applied through the sclerotic and extracted the cataracts using suction. In his Choice of Eye Diseases, written in circa 1000, he wrote of his invention of the hypodermic needle and how he discovered the technique of cataract extraction while experimenting with it on a patient.

Prevention

Although cataracts have no scientifically proven prevention, it is sometimes said that wearing ultraviolet-protecting sunglasses may slow the development of cataracts. Regular intake of antioxidants (such as vitamin A, C and E) is theoretically helpful, but taking them as a supplement has been shown to have no benefit.

Recent research

Although statins are known for their ability to lower lipids, they are also believed to have antioxidant qualities. It is believed that oxidative stress plays a role in the development of nuclear cataracts, which are the most common type of age-related cataract. To explore the relationship between nuclear cataracts and statin use, a group of researchers took a group of 1299 patients who were at risk of developing nuclear cataracts and gave some of them statins. Their results suggest that statin use in an at-risk population may be associated with a lower risk of developing nuclear cataract disease.

Research is scant and mixed but weakly positive for the nutrients lutein and zeaxanthin. Bilberry extract shows promise in rat models and in clinical studies.

In the past few years, eye drops containing acetyl-carnosine have been used by several thousands cataract patients across the world. The drops are believed to work by reducing oxidation and glycation damage in the lens, particularly reducing cristallin cross-linking, The use of these drops remains controversial due to lack of large properly designed trials.

Types of cataracts

Bilateral cataracts in an infant due to Congenital rubella syndrome

The following is a classification of the various types of cataracts. This is not comprehensive and other unusual types may be noted.

• Classified by etiology

· Age-related cataract

· Immature senile cataract (IMSC): partially opaque lens, disc view hazy

· Mature senile cataract (MSC): Completely opaque lens, no disc view

· Hypermature senile cataract (HMSC): Liquefied cortical matter: Morgagnian cataract

· Congenital cataract

· Sutural cataract

· Lamellar cataract

· Zonular cataract

· Total cataract

· Secondary cataract

Slit lamp photo of anterior capsular opacification visible a few months after implantation of Intraocular lens in eye, magnified view

· Drug-induced cataract (e.g. corticosteroids)

· Traumatic cataract

· Blunt trauma (capsule usually intact)

· Penetrating trauma (capsular rupture & leakage of lens material—calls for an emergency surgery for extraction of lens and leaked material to minimize further damage)

• Classified by location of opacity within lens structure (However, mixed morphology is quite commonly seen, e.g. PSC with nuclear changes & cortical spokes of cataract)

· Anterior cortical cataract

· Anterior polar cataract

· Anterior subcapsular cataract

Slit lamp photo of posterior capsular opacification visible a few months after implantation of Intraocular lens in eye, seen on retroillumination

· Nuclear cataract—Grading correlates with hardness & 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 & painless office procedure with Nd:YAG laser capsulotomy to restore optical clarity.

KATARAK

Katarak merupakan penyakit mata yang dicirikan dengan adanya kabut pada lensa mata. Lensa mata normal transparan dan mengandung banyak air, sehingga cahaya dapat menembusnya dengan mudah. Walaupun sel-sel baru pada lensa akan selalu terbentuk, banyak faktor yang dapat menyebabkan daerah di dalam lensa menjadi buram, keras, dan pejal. Lensa yang tidak bening tersebut tidak akan bisa meneruskan cahaya ke retina untuk diproses dan dikirim melalui saraf optik ke otak.

Penyakit katarak banyak terjadi di negara-negara tropis seperti Indonesia. Hal ini berkaitan dengan faktor penyebab katarak, yakni sinar ultraviolet yang berasal dari sinar matahari. Penyebab lainnya adalah kekurangan gizi yang dapat mempercepat proses berkembangnya penyakit katarak.

Apakah Penyebab Katarak ?

Sebagian besar katarak terjadi karena proses degeneratif atau bertambahnya usia seseorang. Katarak kebanyakan muncul pada usia lanjut. Data statistik menunjukkan bahwa lebih dari 90% orang berusia di atas 65 tahun menderita katarak. Sekitar 550% orang berusia 75— 85 tahun daya penglihatannya berkurang akibat katarak. Walaupun sebenarnya dapat diobati, katarak merupakan penyebab utama kebutaan di dunia.

Sayangnya, Seorang penderita katarak mungkin tidak menyadari telah mengalami gangguan katarak. Katarak terjadi secara perlahan-perlahan sehingga penglihatan penderita terganggu secara berangsur. karena umumnya katarak tumbuh sangat lambat dan tidak mempengaruhi daya penglihatan sejak awal. Daya penglihatan baru terpengaruh setelah katarak berkembang sekitar 3—5 tahun. Karena itu, pasien katarak biasanya menyadari penyakitnya setelah memasuki stadium kritis.

Pada awal serangan, penderita katarak merasa gatal-gatal pada mata, air matanya mudah keluar, pada malam hari penglihatan terganggu, dan tidak bisa menahan silau sinar matahari atau sinar lampu. Selanjutnya penderita akan melihat selaput seperti awan di depan penglihatannya. Awan yang menutupi lensa mata tersebut akhirnya semakin merapat dan menutup seluruh bagian mata. Bila sudah sampai tahap ini, penderita akan kehilangan peng­lihatannya.

Secara umum terdapat 4 jenis katarak seperti berikut.

1. Congenital, merupakan katarak yang terjadi sejak bayi lahir dan berkembang pada tahun pertama dalam hidupnya. Jenis katarak ini sangat jarang terjadi.

2. Traumatik, merupakan katarak yang terjadi karena kecelakaan pada mata.

3. Sekunder, katarak yang disebabkan oleh konsumsi obat seperti prednisone dan kortikosteroid, serta penderita diabetes. Katarak diderita 10 kali lebih umum oleh penderita diabetes daripada oleh populasi secara umum.

4. Katarak yang berkaitan dengan usia, merupakan jenis katarak yang paling umum. Berdasarkan lokasinya, terdapat 3 jenis katarak ini, yakni nuclear sclerosis, cortical, dan posterior subcapsular. Nuclear sclerosis merupakan perubahan lensa secara perlahan sehingga menjadi keras dan berwarna kekuningan. Pandangan jauh lebih dipengaruhi daripada pandangan dekat (pandangan baca), bahkan pandangan baca dapat menjadi lebih baik. Penderita juga mengalami kesulitan membedakan warna, terutama warna birru. Katarak jenis cortical terjadi bila serat-serat lensa menjadi keruh, dapat menyebabkan silau terutama bila menyetir pada malam hari. Posterior subcapsular merupakan terjadinya kekeruhan di sisi belakang lensa. Katarak ini menyebabkan silau, pandangan kabur pada kondisi cahaya terang, serta pandangan baca menurun.

Gejala umum gangguan katarak meliputi :

· Penglihatan tidak jelas, seperti terdapat kabut menghalangi objek.

· Peka terhadap sinar atau cahaya.

· Dapat melihat dobel pada satu mata.

· Memerlukan pencahayaan yang terang untuk dapat membaca.

· Lensa mata berubah menjadi buram seperti kaca susu.

katarak dapat pula terjadi pada bayi karena sang ibu terinfeksi virus pada saat hamil muda. Penyebab katarak lainnya meliputi :

· Faktor keturunan.

· Cacat bawaan sejak lahir.

· Masalah kesehatan, misalnya diabetes.

· Penggunaan obat tertentu, khususnya steroid.

· Mata tanpa pelindung terkena sinar matahari dalam waktu yang cukup lama.

· Operasi mata sebelumnya.

· Trauma (kecelakaan) pada mata.

· Faktor-faktor lainya yang belum diketahui.

Klasifikasi Katarak

Katarak dapat diklasifikasikan menjadi :
- katarak Kongenital: Katarak yang sudah terlihat pada usia di bawah 1 tahun
- Katarak Juvenil : katarak yang terjadi sesudah usia 1 tahun
- Katarak Senil: katarak setelah usia 50 tahun
- Katarak Trauma: Katarak yang terjadi akibat trauma pada lensa mata

Etiologi Katarak

Sebagian besar katarak terjadi karena proses degeneratif atau bertambahnya usia seseorang. Usia rata-rata terjadinya katarak adalah pada umur 60 tahun keatas. Akan tetapi, katarak dapat pula terjadi pada bayi karena sang ibu terinfeksi virus pada saat hamil muda.
Penyebab katarak lainnya meliputi :

1. Faktor keturunan.
2. Cacat bawaan sejak lahir.
3. Masalah kesehatan, misalnya diabetes.
4. Penggunaan obat tertentu, khususnya steroid.
5. gangguan metabolisme seperti DM (Diabetus Melitus)
6. gangguan pertumbuhan,
7. Mata tanpa pelindung terkena sinar matahari dalam waktu yang cukup lama.
8. Rokok dan Alkohol
9. Operasi mata sebelumnya.
10. Trauma (kecelakaan) pada mata.
11. Faktor-faktor lainya yang belum diketahui.

Patofisiologi Katarak

Lensa mata mengandung tiga komponen anatomis an: nukleus korteks & kapsul.nukleus mengalami perubahan warna coklat kekuningan seiring dengan bertambahnya usia.disekitar opasitas terdapat densitas seperti duri dianterior & posterior nukleus. Opasitas pada kapsul posterior merupakan bentuk katarak yang paling bermakna.perubahan fisik & kimia dalam lensa mengakibatkan hilangnya transparansi.salah satu teori menyebutkan terputusnya protein lensa normal terjadi disertai infulks air kedalam lensa proses ini mematahkan serabut lensa yang tegang & mengganggu transmisi sinar.teori lain mengatakan bahwa suatu enzim mempunyai peranan dalam melindungi lensa dari degenerasi.jumlah enzim akan menurun dg bertambahnya usia dan tidak ada pada kebanyakan pasien menderita katarak.

Manifestasi Klinik Katarak

Biasanya gejala berupa keluhan penurunan tajam pengelihatan secara progresif (seperti rabun jauh memburuk secara progresif). Pengelihatan seakan-akan melihat asap dan pupil mata seakan akan bertambah putih. Pada akhirnya apabila katarak telah matang pupil akan tampak benar-benar putih ,sehingga refleks cahaya pada mata menja di negatif (-). Bila Katarak dibiarkan maka akan mengganggu penglihatan dan akan dapat menimbulkan komplikasi berupa Glaukoma dan Uveitis.

Gejala umum gangguan katarak meliputi :

1. Penglihatan tidak jelas, seperti terdapat kabut menghalangi objek.
2. Peka terhadap sinar atau cahaya.
3. Dapat melihat dobel pada satu mata.
4. Memerlukan pencahayaan yang terang untuk dapat membaca.
5. Lensa mata berubah menjadi buram seperti kaca susu.

Pemeriksaan Diagnostik Katarak

1. Keratometri.
2. Pemeriksaan lampu slit.
3. Oftalmoskopis.
4. A-scan ultrasound (echography).
5. Penghitungan sel endotel penting u/ fakoemulsifikasi & implantasi.

Pengobatan Katarak

Satu-satunya adalah dengan cara pembedahan ,yaitu lensa yang telah keruh diangkat dan sekaligus ditanam lensa intraokuler sehingga pasca operasi tidak perlu lagi memakai kaca mata khusus (kaca mata aphakia). Setelah operasi harus dijaga jangan sampai terjadi infeksi.
Pembedahan dilakukan bila tajam penglihatan sudah menurun sedemikian rupa sehingga mengganggu pekerjaan sehari-hari atau bila telah menimbulkan penyulit seperi glaukoma dan uveitis.

Tekhnik yang umum dilakukan adalah ekstraksi katarak ekstrakapsular, dimana isi lensa dikeluarkan melalui pemecahan atau perobekan kapsul lensa anterior sehingga korteks dan nukleus lensa dapat dikeluarkan melalui robekan tersebut. Namun dengan tekhnik ini dapat timbul penyulit katarak sekunder. Dengan tekhnik ekstraksi katarak intrakapsuler tidak terjadi katarak sekunder karena seluruh lensa bersama kapsul dikeluarkan, dapat dilakukan pada yang matur dan zonula zinn telah rapuh, namun tidak boleh dilakukan pada pasien berusia kurang dari 40 tahun, katarak imatur, yang masih memiliki zonula zinn. Dapat pula dilakukan tekhnik ekstrakapsuler dengan fakoemulsifikasi yaitu fragmentasi nukleus lensa dengan gelombang ultrasonik, sehingga hanya diperlukan insisi kecil, dimana komplikasi pasca operasi lebih sedikit dan rehabilitasi penglihatan pasien meningkat.

Komplikasi Katarak

• Penyulit yg terjadi berupa : visus tdk akan mencapai 5/5 à ambliopia sensori
• Komplikasi yang terjadi : nistagmus dan strabismus

Pencegahan Katarak
Disarankan agar banyak mengkonsumsi buah-buahan yang banyak mengandung vit.C ,vit.A dan vit E

II. ANATOMI DAN FISIOLOGI LENSA

A. Anatomi Lensa

Lensa adalah suatu struktur bikonveks, avaskular tak berwarna dan transparan. Tebal sekitar 4 mm dan diameternya 9 mm. Dibelakang iris lensa digantung oleh zonula ( zonula Zinnii) yang menghubungkannya dengan korpus siliare. Di sebelah anterior lensa terdapat humor aquaeus dan disebelah posterior terdapat viterus.
Kapsul lensa adalah suatu membran semipermeabel yang dapat dilewati air dan elektrolit. Disebelah depan terdapat selapis epitel subkapsular. Nukleus lensa lebih keras daripada korteksnya. Sesuai dengan bertambahnya usia, serat-serat lamelar subepitel terus diproduksi, sehingga lensa lama-kelamaan menjadi kurang elastik. Lensa terdiri dari enam puluh lima persen air, 35% protein, dan sedikit sekali mineral yang biasa ada di jaringan tubuh lainnya. Kandungan kalium lebih tinggi di lensa daripada di kebanyakan jaringan lain. Asam askorbat dan glutation terdapat dalam bentuk teroksidasi maupun tereduksi. Tidak ada serat nyeri, pembuluh darah atau pun saraf di lensa.

B. Fisiologi Lensa

Fungsi utama lensa adalah memfokuskan berkas cahaya ke retina. Untuk memfokuskan cahaya yang datang dari jauh, otot-otot siliaris relaksasi, menegangkan serat zonula dan memperkecil diameter anteroposterior lensa sampai ukurannya yang terkecil, daya refraksi lensa diperkecil sehingga berkas cahaya paralel atau terfokus ke retina. Untuk memfokuskan cahaya dari benda dekat, otot siliaris berkontraksi sehingga tegangan zonula berkurang. Kapsul lensa yang elastik kemudian mempengaruhi lensa menjadi lebih sferis diiringi oleh peningkatan daya biasnya. Kerjasama fisiologik tersebut antara korpus siliaris, zonula, dan lensa untuk memfokuskan benda dekat ke retina dikenal sebagai akomodasi. Seiring dengan pertambahan usia, kemampuan refraksi lensa perlahan-lahan berkurang. Selain itu juga terdapat fungsi refraksi, yang mana sebagai bagian optik bola mata untuk memfokuskan sinar ke bintik kuning, lensa menyumbang +18.0- Dioptri.

C. Metabolisme Lensa Normal

Transparansi lensa dipertahankan oleh keseimbangan air dan kation (sodium dan kalium). Kedua kation berasal dari humour aqueous dan vitreous. Kadar kalium di bagian anterior lensa lebih tinggi di bandingkan posterior. Dan kadar natrium di bagian posterior lebih besar. Ion K bergerak ke bagian posterior dan keluar ke aqueous humour, dari luar Ion Na masuk secara difusi dan bergerak ke bagian anterior untuk menggantikan ion K dan keluar melalui pompa aktif Na-K ATPase, sedangkan kadar kalsium tetap dipertahankan di dalam oleh Ca-ATPase. Metabolisme lensa melalui glikolsis anaerob (95%) dan HMP-shunt (5%). Jalur HMP shunt menghasilkan NADPH untuk biosintesis asam lemak dan ribose, juga untuk aktivitas glutation reduktase dan aldose reduktase. Aldose reduktse adalah enzim yang merubah glukosa menjadi sorbitol, dan sorbitol dirubah menjadi fructose oleh enzim sorbitol dehidrogenase. Gangguan lensa adalah kekeruhan, distorsi, dislokasi, dan anomali geometrik. Pasien yang mengalami gangguan-gangguan tersebut akan menderita kekaburan penglihatan tanpa nyeri.

References:

www.yahoo.com

www.wikipedia.com

http://kinton.multiply.com/reviews/item/5

http://info.g-excess.com/id/info/PengertiandanDefinisiKatarak.info

konjungtivitis

Conjunctivitis

Creted by: dj_ry_cel@yahoo.co.id / wowo-mm.blogspot.com

Symptoms

Eyes with conjunctivitis

Redness (hyperaemia), irritation (chemosis) and watering (epiphora) of the eyes are symptoms common to all forms of conjunctivitis.

Acute allergic conjunctivitis is typically itchy, sometimes distressingly so, and often involves some lid swelling. Chronic allergy often causes just itch or irritation.

Viral conjunctivitis is often associated with an infection of the upper respiratory tract, a common cold, and/or a sore throat. Its symptoms include watery discharge and variable itch. The infection usually begins with one eye, but may spread easily to the other.

Bacterial conjunctivitis due to the common pyogenic (pus-producing) bacteria causes marked grittiness/irritation and a stringy, opaque, grey or yellowish mucopurulent discharge (gowl, goop, "gunk", "eye crust", or other regional names, officially known as 'gound') that may cause the lids to stick together (matting), especially after sleeping. Another symptom that could be caused by bacterial conjunctivitis is severe crusting of the infected eye and the surrounding skin. However discharge is not essential to the diagnosis, contrary to popular belief. Bacteria such as Chlamydia trachomatis or Moraxella can cause a non-exudative but persistent conjunctivitis without much redness. The gritty and/or scratchy feeling is sometimes localized enough for patients to insist they must have a foreign body in the eye. The more acute pyogenic infections can be painful. Like viral conjunctivitis, it usually affects only one eye but may spread easily to the other eye. However, it is dormant in the eye for three days before the patient shows signs of symptoms.

Irritant or toxic conjunctivitis is irritable or painful when the infected eye is pointed far down or far up. Discharge and itch are usually absent. This is the only group in which severe pain may occur.

Inclusion conjunctivitis of the newborn (ICN) is a conjunctivitis that may be caused by the bacteria Chlamydia trachomatis, and may lead to acute, purulent conjunctivitis.^[3] However, it is usually self-healing.^[3]

Signs

Infection (redness) of the conjunctiva, one of them is by looking at a host pink eye person to person, but may be quite mild. Except in obvious pyogenic or toxic/chemical conjunctivitis, a slit lamp (biomicroscope) is needed to have any confidence in the diagnosis. Examination of the tarsal conjunctiva is usually more diagnostic than the bulbar conjunctiva.

Allergic conjunctivitis shows pale watery swelling or edema of the conjunctiva and sometimes the whole eyelid, often with a ropy, non-purulent mucoid discharge. There is variable redness.

Viral conjunctivitis, commonly known as "pink eye", shows a fine diffuse pinkness of the conjunctiva which is easily mistaken for the 'ciliary injection' of iritis, but there are usually corroborative signs on bio microscopy, particularly numerous lymphoid follicles on the tarsal conjunctiva, and sometimes a punctate keratitis.

Pyogenic bacterial conjunctivitis shows an opaque purulent discharge, a very red eye, and on bio microscopy there are numerous white cells and desquamated epithelial cells seen in the tear duct along the lid margin. The tarsal conjunctiva is a velvety red and not particularly follicular. Non-pyogenic infections can show just mild infection and be difficult to diagnose. Scarring of the tarsal conjunctiva is occasionally seen in chronic infections, especially in trachoma.

Irritant or toxic conjunctivitis show primarily marked redness. If due to splash injury, it is often present only in the lower conjunctival sac. With some chemicals—above all with caustic alkalis such as sodium hydroxide—there may be necrosis of the conjunctiva with a deceptively white eye due to vascular closure, followed by sloughing of the dead epithelium. This is likely to be associated with slit-lamp evidence of anterior uveitis.

Treatment and management

Conjunctivitis sometimes requires medical attention. The appropriate treatment depends on the cause of the problem. For the allergic type, cool water poured over the face with the head inclined downward constricts capillaries, and artificial tears sometimes relieve discomfort in mild cases. In more severe cases, non-steroidal anti-inflammatory medications and antihistamines may be prescribed. Some patients with persistent allergic conjunctivitis may also require topical steroid drops.

Bacterial

Bacterial conjunctivitis usually resolves with no treatment. Treatment with antibiotic eye drops or ointments ( such as chloramphenicol or fusidic acid ) does however speed recovery. Gentamicin and Vigamox, (moxifloxacin) are commonly used in the U.S.^[4] Evidence suggests there is a modest reduction in duration from an average of 4.625 days (untreated controls) to 3.3 days for those given immediate antibiotics. Deferring antibiotics yields almost the same duration as those immediately starting treatment with 3.9 days duration, but with half the two-week clinic reattendance rate.^[5]

Viral

Although there is no specific treatment for viral conjunctivitis, symptomatic relief may be achieved with warm compresses^[6] and artificial tears. For the worst cases, topical corticosteroid drops may be prescribed to reduce the discomfort from inflammation. However prolonged usage of corticosteroid drops increases the risk of side effects. Antibiotic drops may also be used for treatment of complementary infections. Patients are often advised to avoid touching their eyes or sharing towels and washcloths. Viral conjunctivitis usually resolves within 3 weeks. However, in worse cases it may take over a month. In past times breast milk was often used to relieve the symptoms of conjunctivitis.

Chemical

Conjunctivitis due to burns, toxic and chemical require careful wash-out with saline, especially beneath the lids, and may require topical steroids. The more acute chemical injuries are medical emergencies, particularly alkali burns, which can lead to severe scarring, and intraocular damage. Fortunately, such injuries are uncommon.

If you think you might have conjunctivitis, you should

• Keep your hands away from your eyes;
• Thoroughly wash hands before and after applying eye medications;
• Do not share towels, washcloths, cosmetics or eyedrops with others;
• Seek treatment promptly.
• Small children, who may forget these precautions, should be kept away from school, camp and the swimming pool until the condition is cured.

Infectious conjunctivitis, caused by bacteria, is usually treated with antibiotic eye drops and/or ointment. Other infectious forms, caused by viruses, can't be treated with antibiotics. They must be fought off by your body's immune system. But some antibiotics may be prescribed to prevent secondary bacterial infections from developing.

When treating allergic and chemical forms of conjunctivitis, the cause of the allergy or irritation must first be removed. For instance, avoid contact with any animal if it causes an allergic reaction. Wear swimming goggles if chlorinated water irritates your eyes. In cases where these measures won't work, prescription and over-the-counter eye drops are available to help relieve the discomfort.

Pathophysiology

Adenoviral conjunctivitis is the most common cause of viral conjunctivitis. Particular subtypes of adenoviral conjunctivitis include epidemic keratoconjunctivitis (pink eye) and pharyngoconjunctival fever. Transmission occurs through contact with infected upper respiratory droplets, fomites, and contaminated swimming pools.

Primary ocular herpes simplex infection is common in children and usually is associated with a follicular conjunctivitis. Infection usually is caused by HSV type I, although HSV type II may be a cause, especially in neonates. Recurrent infection, typically seen in adults, usually is associated with corneal involvement.

VZV can affect the conjunctiva during primary infection (chickenpox) or secondary infection (zoster). Infection can be caused by direct contact with VZV or zoster skin lesions or by inhalation of infectious respiratory secretions.

Picornaviruses cause an acute hemorrhagic conjunctivitis that is clinically similar to adenoviral conjunctivitis but is more severe and hemorrhagic. Infection is highly contagious and occurs in epidemics.

Molluscum contagiosum may produce a chronic follicular conjunctivitis that occurs secondary to shedding of viral particles into the conjunctival sac from an irritative eyelid lesion.

Vaccinia virus has become a rare cause of conjunctivitis because with the elimination of smallpox, the vaccination rarely is administered. Infection occurs through accidental inoculation of viral particles from the patient's hands.

HIV is the etiologic agent of acquired immunodeficiency syndrome (AIDS). Ocular abnormalities in patients with AIDS primarily affect the posterior segment, but anterior segment findings have been reported. When conjunctivitis occurs in a patient with AIDS, it tends to follow a more severe and prolonged course than in patients without AIDS. In general, patients with AIDS may develop a transient nonspecific conjunctivitis, characterized by irritation, hyperemia, and tearing, that requires no specific treatment. Microsporidia has been isolated from the cornea and conjunctiva of several patients with AIDS and keratoconjunctivitis. In these patients, symptoms included foreign body sensation, blurred vision, and photophobia; most cases resolved without antimicrobial therapy.

Physical Sign/Symptom

• Typical signs of adenoviral conjunctivitis include preauricular adenopathy, epiphora, hyperemia, chemosis, subconjunctival hemorrhage, follicular conjunctival reaction, and occasionally a pseudomembranous or cicatricial conjunctival reaction. The cornea often demonstrates a punctate epitheliopathy. The eyelids often are edematous and ecchymotic. In severe cases, there can be a corneal epithelial defect. It typically begins in one eye and progresses to the fellow eye over a few days. The second eye is usually less significantly involved.
• With HSV infection, vesicles may be present on the eyelid or face, the eyelids may be swollen, and an ulcerative blepharitis may be present.
• Corneal involvement in HSV manifests as a dendritic keratitis with typical features of linear branching and dendritic figures.
• Small papular lesions that erupt along the lid margin or at the limbus are present with varicella conjunctivitis. These lesions may resolve without sequelae, or they may become pustular and form painful reactive conjunctival ulcers.
• In herpes zoster ophthalmicus, look for skin involvement with the appearance of a dermatomal pattern of vesicles. These vesicles may become necrotic, resulting in pitted scarring of the skin. Conjunctival involvement includes hyperemia, follicular or papillary conjunctivitis, and a serous or mucopurulent discharge. Preauricular adenopathy is common. Very early in the process, there may be multiple fine dendritic corneal lesions, which disappear over a few days without treatment.
• Acute hemorrhagic conjunctivitis starts unilaterally but rapidly involves the fellow eye within 1 or 2 days. Signs on examination include a swollen, edematous eyelid, and pronounced hemorrhage beneath the bulbar conjunctiva.

Causes

A variety of viruses can be responsible for conjunctival infection. Adenovirus is the most common cause, and HSV is the most problematic. Less common causes include VZV, picornavirus (enterovirus 70, Coxsackie A24), poxvirus (molluscum contagiosum, vaccinia), and HIV.

Treatment

Medical Care

Treatment of adenoviral conjunctivitis is supportive. No evidence exists that demonstrates efficacy of antiviral agents.

• Patients should be instructed to use cold compresses and lubricants, such as artificial tears, for comfort.
• Topical vasoconstrictors and antihistamines may be used for severe itching but generally are not indicated because they are minimally helpful and may cause rebounding of symptoms, as well as local toxicity and hypersensitivity.
• For patients who may be susceptible, a topical astringent or antibiotic may be used to prevent bacterial superinfection.
• Topical steroids may be used for pseudomembranes or when subepithelial infiltrates impair vision, although subepithelial infiltrates may recur after discontinuing the steroids. Extreme caution should be taken when using corticosteroids, as they may worsen an underlying HSV infection.
• An in vitro study using adenovirus 8 and A549 human epithelial cell cultures demonstrated that povidone-iodine at a concentration of 1:10 (0.8%) is highly effective against free adenovirus, less effective against intracellular adenoviral particles in already infected cells, and not significantly cytotoxic for healthy cells. Thus, povidone-iodine 0.8% may represent a potential option to reduce contagiousness in cases of adenoviral infections.
• Patients with conjunctivitis caused by HSV usually are treated with topical antiviral agents, including idoxuridine solution and ointment, vidarabine ointment, and trifluridine solution. An ophthalmologist should see any patient with ocular HSV infection. Treatment of HSV keratitis is discussed in Keratitis, Herpes Simplex.
• Treatment of VZV eye disease includes oral acyclovir, 600-800 mg, 5 times daily for 7-10 days, to terminate viral replication. Topical corticosteroids usually are not indicated for conjunctivitis or keratitis.
• Treatment of acute hemorrhagic conjunctivitis is supportive as in adenoviral infection and includes bed rest, cold compresses, and analgesics. Antibiotics have no useful role unless bacterial superinfection is present.
• For conjunctivitis associated with molluscum contagiosum, disease will persist until the skin lesion is treated. Removal of the central core of the lesion or inducement of bleeding within the lesion usually is enough to cure the infection. Occasionally, surgical excision is required.
• Other viral causes of conjunctivitis generally are self-limited and treated supportively with compresses for comfort and topical antibiotics as necessary to prevent bacterial superinfection.

Medication

Medications used in the treatment of viral conjunctivitis include the following: topical artificial tears, 4-8 times per day, for 1-3 weeks; topical vasoconstrictor/antihistamine, 4 times per day, for severe itching; topical steroids for pseudomembranes and subepithelial infiltrates; topical antibiotic to prevent bacterial superinfection; topical antiviral agents for HSV infection; and oral acyclovir for VZV infection.

Deterrence/Prevention

• Prevention of transmission, especially in health care facilities, is extremely important.
• Careful hand washing before seeing every patient, proper cleansing of instruments, and frequent changing of multiuse ophthalmic drops are vital.
• Using a single infective examination room, as well as educating the staff and the patient, is important.
• Patients should be instructed to take contagion and isolation precautions for at least 2 weeks or as long as the eyes are red and weeping.

Complications

• Complications include the following: punctate keratitis with subepithelial infiltrates, bacterial superinfection, corneal ulceration with keratoconjunctivitis, and chronic infection.
• Epithelial keratitis may accompany viral conjunctivitis. Punctate epithelial erosions that stain with fluorescein characterize viral keratitis. Rarely, these changes are sufficiently distinctive morphologically to allow identification of a specific type of virus as the etiologic agent. If the conjunctivitis persists or is severe, disturbances in the anterior stroma beneath the epithelial abnormalities may occur. In general, the stromal or subepithelial abnormalities are transient and resolve despite persistence of epithelial keratitis. However, in cases of adenoviral infection, the stromal abnormalities may persist for months to years, long after the epithelial changes have resolved. In such cases, these subepithelial infiltrates are considered to be immunologic in origin, the result of antigen-antibody reaction. If they are in the pupillary axis, they may cause decreased vision and/or glare.

Prognosis

• Most cases of viral conjunctivitis are acute, benign, and self-limited. The infection usually resolves spontaneously within 2-4 weeks. Subepithelial infiltrates may last for several months, and, if in the visual axis, they may cause decreased vision or glare.

References

http://www.wikipedia.com

http://emedicine.medscape.com