Glaucoma treatments

Glaucoma Treatments

Glaucoma is commonly treated with eye drops, and surgery for some forms or when drug therapy is not effective.

There are a number of different categories of eye drops, but all are used to either decrease the amount of fluid (aqueous humor) in the eye or improve its outward flow. Sometimes doctors will prescribe a combination of eye drops.

People using these medications should be aware of their purpose and potential side effects, which should be explained by a medical professional.

Types of Medications

1. Alpha adrenergic agonists

Action  reduce aqueous humor production and increase its outflow.

Side effects Allergic reactions frequently occur with this class of medication, increased heart rate, elevated blood pressure, headaches, blurry vision, fatigue, dry mouth, and redness in or around the eye.

Examples

• apraclonidine (Iopidine)
• brimonidine (Alphagan)
• epinepherine (Gluacon and Epifrin)
• dipivefrin (Propine)

2. Beta blockers

Action work to lower eye (intraocular) pressure by decreasing the rate at which fluid flows into the eye.

Side effects may include a slow or irregular heartbeat, depression, impotence, drowsiness, double vision, and breathing problems for patients with asthma or emphysema.

Examples

• timolol (Timoptic XE Ocumeter and Timoptic)
• levobunolol (Betagan)
• carteolol (Ocupress)
• metipranolol (OptiPranolol)
• betatoxol (Betoptic)

3. Carbonic anhydrase inhibitors       (eye drops or pills )

Action  used to reduce fluid production in the eye.

Side effects may include skin rash, eye redness or irritation, headache, nausea or upset stomach, altered taste (especially with carbonated beverages), weight loss, fatigue and decreased energy.

Examples

• dorzolamide (Trusopt)
• brinzolamide (Azopt)
• acetazolamide (Diamox) – oral medication
• methazolamide (Neptazane) – oral medication

4. Miotics (cholinergic agents)

Action help increase the rate of fluid drainage from the eye.

Side effects may include red eyes, headache, and blurry or cloudy vision.

Examples

• pilocarpine (Isopto Carpine, Travatan ,Pilocar and Pilopine HS ointment)
• echothiophate (Phospholine Iodide)

5. Prostaglandin analogs

Action reduce pressure in the eye by increasing the outward flow of fluid from the eye.

Side effects may include eye redness or irritation, a change in eye color (mostly in hazel or green eyes), increase in thickness and number of eyelashes, and joint aches or flu-like symptoms.

Examples

• latanoprost (Xalatan)
• bimatoprost (Lumigan)
• travoprost (Travatan)

 6. Combinations of eye drops

 Also used to achieve better results.

 Side effects for these medications are mentioned above.

Examples

• dorzolamide and timolol (Cosopt)
• latanoprost and timolol (Xalacom)
• brimonidine and timolol (Combigen™)

                         


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Conventional Filtration Surgery

Normally, conventional filtration surgery is used as a therapy for glaucoma after other treatment strategies, such as medications and laser surgery, have failed. It is most often performed with the open-angle form of the disease. Two procedures are used almost exclusively or only for infants with congenital glaucoma. When deciding on a treatment option, an ophthalmologist will take into account the unique aspects of each person’s case, including severity of the disease, response to medication and other health issues.

                                          

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Laser Surgery

Depending in the type of procedure, laser surgery may be used for open-angle, closed-angle or neovascular glaucoma. A laser is directed toward the trabecular meshwork, the iris, ciliary body or the retina and is used in various ways to reduce eye pressure. Laser surgery is performed on an outpatient basis in an eye doctor’s office or clinic after the eye has been numbed.

glaucoma

Glaucoma   "silent thief of sight"

Glaucoma is a complicated disease in which damage to the optic nerve leads to progressive, irreversible vision loss.  (The optic nerve receives light-generated nerve impulses from the retina and transmits these to the brain, where we recognize those electrical signals as vision. Glaucoma is characterized by a particular pattern of progressive damage to the optic nerve that generally begins with a subtle loss of side vision ).

 If glaucoma is not diagnosed and treated, it can progress to loss of central vision and blindness.
Glaucoma is theThe second leading cause of blindness.

It is often, but not always, associated with increased pressure of the fluid in the eye aqueous humour( which provides nourishment to the structures in the front of the eye ).
The term 'ocular hypertension' is used for cases having constantly raised intraocular pressure (IOP) without any associated optic nerve damage. But mostely,  this elevated eye pressure  leads to damage of the eye (optic) nerve.


 In some cases, glaucoma may occur in the presence of normal eye pressure. This form of glaucoma is believed to be caused by poor regulation of blood flow to the optic nerve.

 Glaucoma affects 1 in 200 people aged fifty and younger, and 1 in 10 over the age of eighty. If the condition is detected early enough it is possible to arrest the development or slow the progression with medical and surgical means.

Types of Glaucoma

Glaucoma is actually a group of diseases. The most common type is hereditary.

• Primary Open-Angle Glaucoma
• Angle-Closure Glaucoma
• Normal-Tension Glaucoma
• Other Types of Glaucoma



1. Primary Open-Angle Glaucoma
   This is the most common form of glaucoma .

With open-angle glaucoma, the entrances to the drainage canals are clear and should be working correctly. The clogging problem occurs further inside the drainage canals, similar to a clogged pipe below the drain in a sink.

 Most people have no symptoms and no early warning signs. If open-angle glaucoma is not diagnosed and treated, it can cause a gradual loss of vision. The subsequent loss of side vision (peripheral vision) is usually not recognized. That's why it  has been nicknamed the "silent thief of sight"
This type of glaucoma is usually responds well to medication, especially if caught early and treated.

 A slow chronic increase in eye pressure is probably not painful. In contrast, there is discomfort and pain when the eye pressure increases rapidly during an acute onset or with the rapid return of glaucoma following unsuccessful glaucoma surgery. Lowering high eye pressure relieves these painful symptoms quickly.

2. Angle-Closure Glaucoma   ( closed-angle glaucoma)

This type of glaucoma is also known as acute glaucoma or narrow angle glaucoma. It is much more rare and is very different from open-angle glaucoma in that the eye pressure usually rises very quickly.
This happens when the drainage canals get blocked or covered over, like a sink with something covering the drain.
With angle-closure glaucoma, the iris is not as wide and open as it should be. The outer edge of the iris bunches up over the drainage canals, when the pupil enlarges too much or too quickly. This can happen when entering a dark room.

Symptoms of angle-closure glaucoma may include:

• Hazy or blurred vision
• The appearance of rainbow-colored circles around bright lights
• Severe eye and head pain
• Nausea or vomiting (accompanying severe eye pain)
• Sudden sight loss

In contrast with open-angle glaucoma, symptoms of acute angle-closure glaucoma are very noticeable and damage occurs quickly. If you experience any of these symptoms, seek immediate care from an ophthalmologist.


3. Normal-Tension Glaucoma  (normal-pressure glaucoma)

Normal-tension glaucoma (NTG) is a form of glaucoma in which damage occurs to the optic nerve without eye pressure exceeding the normal range. In general, a "normal" pressure range is between 10-20 mm Hg.
 The causes of NTG are still unknown. For some reason, the optic nerve is susceptible to damage from even the normal amount of eye pressure.
Those at higher risk for this form of glaucoma are:

• people with a family history of normal-tension glaucoma
• people of Japanese ancestry
• people with a history of systemic heart disease such as irregular heart rhythm.

4. Other Types of Glaucoma

Secondary Glaucom

Secondary glaucoma refers to any case in which another disease causes or contributes to increased eye pressure, resulting in optic nerve damage and vision loss.
Secondary glaucoma can occur as the result of an eye injury, inflammation, tumor, or in advanced cases of cataract or diabetes. It can also be caused by certain drugs such as steroids. This form of glaucoma may be mild or severe. The type of treatment will depend on whether it is open-angle or angle-closure glaucoma.

Pigmentary Glaucoma

Pigmentary Glaucoma is a form of secondary open-angle glaucoma. It occurs when the pigment granules that are in the back of the iris (the colored part of the eye) break into the clear fluid produced inside the eye. These tiny pigment granules flow toward the drainage canals in the eye and slowly clog them. This causes eye pressure to rise. Treatment usually includes medications, laser surgery, or conventional surgery.

Pseudoexfoliative Glaucoma

This form of secondary open-angle glaucoma occurs when a flaky, dandruff-like material peels off the outer layer of the lens within the eye. The material collects in the angle between the cornea and iris and can clog the drainage system of the eye, causing eye pressure to rise. Pseudoexfoliative Glaucoma is common in those of Scandinavian descent. Treatment usually includes medications or surgery.

Traumatic Glaucoma

Injury to the eye may cause secondary open-angle glaucoma. Traumatic glaucoma can occur immediately after the injury or years later. It can be caused by blunt injuries that bruise the eye (called blunt trauma) or by injuries that penetrate the eye.
In addition, conditions such as severe nearsightedness, previous injury, infection, or prior surgery may make the eye more vulnerable to a serious eye injury.

Neovascular Glaucoma

The abnormal formation of new blood vessels on the iris and over the eye's drainage channels can cause a form of secondary open-angle glaucoma.
Neovascular glaucoma is always associated with other abnormalities, most often diabetes. It never occurs on its own. The new blood vessels block the eye's fluid from exiting through the trabecular meshwork (the eye's drainage canals), causing an increase in eye pressure. This type of glaucoma is very difficult to treat.

Irido Corneal Endothelial Syndrome (ICE)

This rare form of glaucoma usually appears in only one eye, rather than both. Cells on the back surface of the cornea spread over the eye's drainage tissue and across the surface of the iris, increasing eye pressure and damaging the optic nerve. These corneal cells also form adhesions that bind the iris to the cornea, further blocking the drainage channels.
Irido Corneal Endothelial Syndrome occurs more frequently in light-skinned females. Symptoms can include  hazy vision upon awakening and the appearance of halos around lights. Treatment can include medications and filtering surgery. Laser therapy is not effective in these cases.

Congenital Glaucoma (Childhood Glaucoma)

Childhood Glaucoma refers to the presence of glaucoma in a child, and occurs in 1 out of every 10,000 births in the United States. Congenital glaucoma is the common term used for a glaucoma diagnosed in infancy or early childhood.
This glaucoma is caused by abnormal intraocular fluid drainage from the eye as a result of a blocked or defective trabecular meshwork (the mesh-like drainage canals in the eye). Congenital glaucoma may be due to an hereditary defect or abnormal development during pregnancy.
In other cases, an abnormal drainage system may be the result of some other disease in the eye which results in secondary glaucoma. In these cases, the glaucoma may be associated with recognizable iris (the colored part of the eye), corneal, or other eye problems.
In an uncomplicated case of congenital glaucoma, microsurgery can often correct the structural defects. Other cases are treated with medication and surgery.

Symptoms of childhood glaucoma

• light sensitivity (photophobia)
• corneal opacification (hazy gray cornea)
• enlarged eye and cornea
• epiphora (overflow of tears)
• vision loss

A cloudy cornea is the earliest and most common sign of childhood glaucoma. The healthy cornea is transparent. The loss of this transparency is caused by edema, or swelling of tissue from excess fluid. This occurs in the corneal epithelium (outermost layer of the cornea) and in the corneal stroma (middle layer of the corneal tissue). Careful inspection of the cornea may also reveal defects in its inner layer, which is further proof of a raised eye pressure (IOP).

In most cases of glaucoma affecting children under three years of age, the cornea and eye enlarges. Review of early photographs of your child may reveal the presence of glaucoma months before the diagnosis was actually made.

In addition to eye problems, secondary systemic (body) symptoms may occur. These secondary symptoms are especially common with acute glaucoma. Examples include irritability, loss of appetite, and vomiting. These symptoms may be misunderstood before the glaucoma is recognized. Young children with glaucoma are often unhappy, fussy, and poor eaters.

Cataract

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.

 The natural lens sits behind the colored part of the eye (iris) in the area of the pupil, and cannot be directly seen with the naked eye unless it becomes extremely cloudy. The lens plays a crucial role in focusing unimpeded light on the retina at the back of the eye. The retina transforms light to a neurologic signal that the brain interprets as vision. Significant cataracts block and distort light passing through the lens, causing visual symptoms and complaints.

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.

 Many people are in fact unaware that they have cataracts because the changes in their vision have been so gradual.

When people develop cataracts, they begin to have difficulty doing activities they need to do for daily living or for enjoyment. Some of the most common complaints include difficulty driving at night, reading, participating in sports such as golfing, or traveling to unfamiliar areas; these are all activities for which clear vision is essential.

Cataracts are very common, affecting roughly 60% of people over the age of 60, and over 1.5 million cataract surgeries are performed in the United States each year.



Causes of Cataract

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 

. Advanced age, or trauma (possibly much earlier)

. The use of certain medications, such as oral, topical, or inhaled steroids. Other medications that are more weakly associated with cataracts include the long-term use of statins and phenothiazines.

. Exposure to microwave radiation .

. Atopic or allergic conditions are also known to quicken the progression of cataracts, especially in children.

 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.



Classification of cataract

1.  Age-related cataract

A. Senile Cataract   ( an initial opacity in the lens, subsequent swelling of the lens and final shrinkage with complete loss of transparency in eldery)

a.Cortical Senile Cataract   ( opacities are most visible in the outside of the lens which is called the lens cortex)

·         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

b. Senile Nuclear Cataract   ( the central portion of the lens is most affected, which is the most common situation)

·   Cataracta brunescens

·   cataracta nigra

·   cataracta rubra

B. Congenital cataract      ( Cataracts that occur at birth or present very early in life during the first year of life )

·         Sutural cataract

·         Lamellar cataract

·         Zonular cataract

·         Total cataract

These cataracts require prompt surgical correction or they may prevent the vision in the affected eye from developing normally.

2. 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)

      3. 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)

There is an even more specific change that occasionally happens, when the opacity develops immediately next to the lens capsule, either by the anterior, or more commonly the posterior, portion of the capsule; these are called subcapsular cataracts. Unlike most cataracts, posterior subcapsular cataracts can develop rather quickly and affect vision more suddenly than either nuclear or cortical cataracts.

People who have a higher risk of developig this form of cataract are:  people with diabetes, high farsightedness, retinitis pigmentosa or those taking high doses of steroids.

symptoms

Each type of cataract has its own symptoms. With a nuclear cataract you may notice an improvement in your near vision. This is called 'second sight'. However when the cataract gets worse this will disappear.
A subcapsular cataract may not give any symptoms in the beginning, but only in a later stage when it is more developed.

 Symptoms of a cataract

·    Cloudy or blurry vision.

·    Colors seem faded.

·    Glare. Headlights, lamps, or sunlight may appear too bright. A halo may appear around lights.

·    Poor night vision.

·    Double vision or multiple images in one eye. (This symptom may clear as the cataract gets larger.)

·    Frequent prescription changes in your eyeglasses or contact lenses.

·    These symptoms also can be a sign of other eye problems. If you have any of these symptoms, check with your eye care professional.

At first, the amount of tinting may be small and may not cause a vision problem. Over time, increased tinting may make it more difficult to read and perform other routine activities. This gradual change in the amount of tinting does however not affect the sharpness of the image transmitted to the retina.

In advanced lens discoloration the ability to identify blues and purples is decreased. Black is seen instead of purple or blue.

Treatment of Cataract

A diet high in antioxidants, such as beta-carotene (vitamin A), selenium and vitamins C and E, may forestall cataract development. Meanwhile, eating a lot of salt may increase your risk.Eating high amounts of meat increase the risk of Cataract too. 

   The study examined the dietary surveys filled out by 27,670 self-reported nondiabetic people aged 40 or over and monitored their medical records to see if and when cataracts developed. Strong correlations showed up between cataract risk and diet type.

The risk was greatest for high meat eaters (who ate more than 3.5 ounces of meat each day), and it decreased from one group to the next, in this order: moderate meat eaters, low meat eaters, fish eaters (people who eat fish but no other meat), vegetarians and vegans. In fact, the risk for vegans was roughly 40 percent lower than for the high meat eaters.

          

 you should only consider surgery when your cataracts have progressed so far that they seriously impair your vision.

Cataract surgery

 is very successful in restoring vision. In fact, it is the most frequently performed surgery in the United States, with more than 3 million Americans undergoing cataract surgery each year. Nine out of 10 people who have cataract surgery regain very good vision, somewhere between 20/20 and 20/40.

During surgery, the surgeon will remove your clouded lens and in most cases replace it with a clear, plastic intraocular lens (IOL).

New IOLs are being developed all the time to make the surgery less complicated for surgeons and the lenses more helpful to patients. Presbyopia-correcting IOLs potentially help you see at all distances, not just one. Another new type of IOL blocks both ultraviolet and blue light rays, which research indicates may damage the retina.

Risks of surgery

Some common problems can occur after surgery. These may include increased pressure, blurring from swelling, inflammation (pain, redness, swelling), and sometimes bleeding. More rare and serious problems include infection, loss of vision, or light flashes. If you experience increasing pain or a worsening of vision after surgery, you should contact your eye doctor. With prompt medical attention, almost all problems can be treated successfully.

Cataract surgery slightly increases your risk of retinal detachment. Other eye disorders, such as high myopia (nearsightedness), can further increase your risk of retinal detachment after cataract surgery.

Sometimes the eye tissue that encloses the IOL becomes cloudy after the operation and may blur your vision. This condition, called an after-cataract, can develop months or years after cataract surgery.

eye

Description

Eyes are organs that detect light, and convert it to electro-chemical impulses in neurons.

 In higher organisms the eye is a complex optical system which collects light from the surrounding environment; regulates its intensity through a diaphragm; focuses it through an adjustable assembly of lenses to form an image; converts this image into a set of electrical signals; and transmits these signals to the brain, through complex neural pathways that connect the eye, via the optic nerve, to the visual cortex and other areas of the brain.

-The eye is not properly a sphere, rather it is a fused two-piece unit. The smaller frontal unit, more curved, called the cornea is linked to the larger unit called the sclera. The cornea and sclera are connected by a ring called the limbus.

-The iris ( the color of the eye )and  the pupil (its black center)are seen instead of the cornea due to the cornea's transparency.

-The fundus (area opposite the pupil) shows the characteristic pale optic disk ,papilla, where vessels entering the eye pass across and optic nerve fibers depart the globe.

The eye is made up of three coats, enclosing three transparent structures:

1. The outermost layer is composed of the cornea and sclera.

2. The middle layer consists of the choroid, ciliary body, and iris.

3. The innermost is the retina, which gets its circulation from the vessels of the choroid as well as the retinal vessels, which can be seen in an ophthalmoscope.

Within these coats are the aqueous humor, the vitreous body, and the flexible lens.

1. The aqueous humor is a clear fluid that is contained in two areas: the anterior chamber between the cornea and the iris and exposed area of the lens; and the posterior chamber, behind the iris and the rest.                 2. The vitreous body is a clear jelly that is much larger than the aqueous humor, and is bordered by the sclera, zonule, and lens. They are connected via the pupil.

 3. The lens is suspended to the ciliary body by the suspensory ligament (Zonule of Zinn), made up of fine transparent fibers.

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Eye irritation

Eye irritation has been defined as “the magnitude of any stinging, scratching, burning, or other irritating sensation from the eye”.

It is a common problem experienced by people of all ages. Related eye symptoms and signs of irritation are e.g. discomfort, dryness, excess tearing, itching, grating, sandy sensation, smarting, ocular fatigue, pain, scratchiness, soreness, redness, swollen eyelids, and tiredness, etc. These eye symptoms are reported with intensities from severe to less severe. It has been suggested that these eye symptoms are related to different causal mechanisms.

Several suspected causal factors in our environment have been studied so far:

-One hypothesis is that indoor air pollution may cause eye and airway irritation.

-Occupational factors are also likely to influence the perception of eye irritation. Some of these are lighting (glare and poor contrast), gaze position, a limited number of breaks, and a constant function of accommodation, musculoskeletal burden, and impairment of the visual nervous system.

-In addition, psychological factors have been found in multivariate analyses to be associated with an increase in eye irritation among VDU users.

-Other risk factors, such as chemical toxins/irritants, e.g. Amines, Formaldehyde, Acetaldehyde, Acrolein, N-decane, VOCs; Ozone, Pesticides and preservatives, Allergens, etc might cause eye irritation as well.

 -Personal factors (e.g., use of contact lenses, eye make-up, and certain medications) may also affect destabilization of the tear film and possibly result in more eye symptoms.

- Contact lenses and gender differences, there are more and more people wearing contact lens now and dry eyes appear to be the most common complaint among contact lens wearers. Although both contact lens wearers and spectacle wearers experience similar eye irritation symptoms, dryness, redness, and grittiness have been reported far more frequently among contact lens wearers and with greater severity than among spectacle wearers.

The incidence of dry eyes increases with age. Tear film stability (eg. break-up time) is significantly lower among women than among men. In addition, women have a higher blink frequency while reading.

eye irritation was the most frequent symptom in industrial building spaces. Since the 1970s, reports have linked mucosal, skin, and general symptoms to work with self-copying paper. Emission of various particulate and volatile substances has been suggested as specific causes. These symptoms have been related to Sick Building Syndrome (SBS), which involves symptoms such as irritation to the eyes, skin, and upper airways, headache and fatigue.

 Conditions of eye irritation 
1 . Conjunctivitis (Pink Eye)

Conjunctivitis, or pink eye, is an inflammation of the conjunctiva. The conjunctiva is a clear mucus membrane that lines the inside of the eyelid and covers the white part of the eye. The most obvious symptom of pink eye is a red or "pink" colored eye. Inflammation causes small blood vessels in the conjunctiva to darken, resulting in a pink or red tint to the white of the eye.


2 . Eye Allergies

Many people complaining of eye irritation are diagnosed with seasonal eye allergies. Eye allergies sometimes cause significant discomfort, often interrupting daily activities with annoying symptoms.



3 . Dry Eye Syndrome

If your eyes feel dry, have a stinging sensation, or feel scratchy, you may have dry eye syndrome. Dry eye syndrome is a condition that can occur when the tear glands don't produce the correct quantity or quality of tears.

 4 .Blepharitis

Blepharitis commonly causes red, crusty eyelids. If you have blepharitis, your symptoms are probably most noticeable upon awakening in the morning.



5 .Corneal Ulcer

A corneal ulcer is an erosion or open sore on the surface of the cornea. Corneal ulcers are common in people who wear contact lenses, especially if they wear them overnight.

Prevention of eye irritation

Several actions can be taken to prevent eye irritation:

.Trying to maintain normal blinking by avoiding room temperatures that are too high; avoiding relative humidities that are too high or too low, because they reduce blink frequency or may increase water evaporation.

.Trying to maintain an intact tear film by the following actions:

1) blinking and short breaks may be beneficial for VDU users. 

2) downward gazing is recommended to reduce the ocular surface area and water evaporation.

3) the distance between the VDU and keyboard should be kept as short as possible to minimize evaporation from the ocular surface area by a low direction of the gaze.

4) blink training can be beneficial.

Treatment for eye irritation

Artificial tears eye drops

Apply cold compresses:

• Apply for 20-30 minutes, every 1-2 hours, for the first few days.

Avoid exposure to smoke.

Avoid rubbing the eyes.

Avoid using eye makeup.

Do not use contact lenses until your symptoms are gone.

Take an antihistamine for itching:

• Diphenhydramine (Benadryl)