Amblyopia is commonly known as'lazy eye. It is a vision development disorder, which affects eyes and the brain during infancy and childhood. It signifies that the eye does not achieve a normal visual acuity even with refractive correction in form of glasses or contact lens. During normal visual development, the eye and brain learns to'see' and develop binocularity, that is the ability to perceive depth (stereoacuity). This occurs in the first 8 to 10 years of life. 

Each eye transmits a clear and identical image from retina to the brain, which fuses the two images into a single image with 3 dimensions (adding depth). When the image is formed on the retina of two eyes is too dissimilar, the brain cannot fuse the two images and suppresses the more blurred image. As a result, the worse eye does not learn to'see' and becomes'lazy. This condition is seen in 1-4% of population.

The common causes for dissimilar images or amblyopia are:
1. Misalignment of the eyes or squint: it is the primary reason for amblyopia is misalignment of the eyes. In case, both your eyes are not aimed in the same direction, the image captured by each eye is different, resulting in diplopia. The brain will see from the dominant eye and suppress image from the other eye. Over a prolonged period of time, the eye dissociates from the visual cortex of the brain.

2. Refractive amblyopia:
A. Unequal refractive error in both eye. When the eye power of both eyes differ by more than 1.5d of spherical equivalent, which results in dissimilar images between the two eyes. As a result, the visual development in restricted in the worse eye.
B. High refractive error or astigmatism in both eyes, since there is a blurred image in both eyes, the normal vision development does not occur in either eyes resulting in bilateral lazy eyes.

3. Cloudiness in visual system or visual deprivation amblyopia: any kind of obstruction or cloudiness in the normal visual axis of the eye tissues can lead to amblyopia. Disorder of any kind, which blocks a clear image from being focused blocks the formation of a clear image on your retina. Commonly due to congenital or developmental cataracts or corneal opacities or prolonged closure of one eye in early childhood (drooping of one eyelid, eyelid swelling, patching of one eye).

Treatment for amblyopia
For treatment of amblyopia, a child must be compelled to utilize his affected, weaker eye. This can be done by correction of causative factor such as, treating refractive error with glasses, surgical correction of misalignment of eyes followed by patching and vision therapy, cataract surgery.

Patching or occlusion of the good eye
This is done to force the brain to pay attention to visual input from the worse eye. This allows nerve connections between affected eye and brain to develop due to, which the eye'learns to see. Eye drops such as atropine are also used for blurring the vision of the good eye. Some form of vision therapy may also be required to train both eyes to see together and develop some degree of depth perception.

To be effective, treatment should be implement as early as possible, within the period of normal visual development best within first 8 years of life. Some visual gain has been seen in selected patients up to age of 14 to 18 years. This also highlights the importance of a comprehensive eye examination as a routine in young children.

About Amblyopia or Lazy Eye

Glaucoma is a group of eye diseases characterised by damage to optic nerve usually due to excessively high intra ocular pressure (eye pressure). If left untreated can lead to optic nerve damage resulting in progressive, permanent vision loss. Glaucoma usually affects people above the age of 40, but can affect younger people as well. This condition causes fluid to build up in the eye, which puts pressure on the optic nerve. 

There are broadly two types of glaucoma - Open angle glaucoma ( more common in elderly) and angle closure glaucoma.
Women are more likely to suffer from glaucoma than men are. Ethnicity also plays an important role in determining the risk of suffering from this condition. East Asian and African Americans have a high risk of glaucoma, as they have a shallow, anterior chamber depth. Some of the other conditions that can increase a person s risk of glaucoma are:

Diabetes
Hypothyroidism
Myopia
An earlier eye surgery
Retinal detachment
Tumours
Injury to the eye
Long term corticosteroid medication
If diagnosed early enough, glaucoma can be treated and its effects can be reduced. However, the damage already caused by glaucoma cannot be reversed. The aim of glaucoma treatment is to either reduce the production of fluid in the eye or improve its flow. This helps slow down the progression of this disease and prevents any further loss of vision. Glaucoma treatment usually takes the form of eye drops or surgery.

Eye drops are the first step towards treating glaucoma. There are many different types of eye drops. Prostaglandin analogues aim at increasing the flow of fluid out of the eye and are usually prescribed in cases of swelling around the rim of the eyes, darkening of the iris and blurred vision. Beta-blockers can also help lower the secretion of fluids in the eye.

Patients who are also suffering from diabetes or lung conditions such as bronchitis may be prescribed cholinergic agents, carbonic anhydrase inhibitors or sympathomimetic drugs. Cholinergic agents help improve the outward flow of fluid in the eyes while Carbonic anhydrase inhibitors reduce fluid production in the eyes. Sympathomimetic drugs do both reduce the production of fluids and improve outflow.

If the eye drops are not effective, surgery may be advised to lower the pressure built up in the eye. Some of the common types of surgery for glaucoma are:

Trabeculoplasty: This procedure involves directing a high-energy laser beam into the eye to open clogged drainage canals. The surgery has high success rates but the problem may recur after surgery.
Filtering surgery: This involves creating an opening in the eye and removing a part of the trabecular meshwork, thus allowing fluid to flow outwards.
Drainage implants: Children or patients with secondary glaucoma may be treated with this surgery where a small silicone tube is placed in the eye to aid in fluid drainage.

Glaucoma - Factors That Put You Risk!

Hypertension is a killer disease whose symptoms develop late when the damage is in advanced stages. Hypertensive Retinopathy is one such disease.

It damages the retina of eyes. Since retina is responsible for vision formation, Hypertensive Retinopathy can result in loss of vision. It is of grave concern that in most cases, Hypertensive Retinopathy is diagnosed later.

This is due to the fact that there are often no symptoms in the early stages of the disease. In some cases, where symptoms do manifest, patients may experience pain in the eyes, reduced vision, or headache.

What Happens in Hypertensive Retinopathy

People suffering from long term hypertension are susceptible to Hypertensive Retinopathy. Long-term hypertension affects the small and narrow blood vessels that join arteries to capillary blood vessels taking blood to different parts of the eye. These blood vessels become narrow with time if hypertension in the eyes continues unabated. This narrowing is more common in young adults compared to older people. Such unabated systemic hypertension also leads to leakage of fluid. This is why in some cases of Hypertensive Retinopathy, patients may experience exudation. Ultimately, Hypertensive Retinopathy may lead to damage to retinal blood vessels.

Risk Factors

Long standing hypertension is the number one risk factor for Hypertensive Retinopathy. People who are suffering from longer hypertension become most susceptible for this ailment.

However, studies have shown that hypertension for more than 5 years can even make people susceptible to this ailment.

Diagnosis

Diagnosis is done by Funduscopic Examination. The doctor would look at the eyes of the patient through an Ophthalmoscope which has different lenses. The Ophthalmoscope illuminates the retina and the doctor looks at the retina with different lenses. He can get a view of the retina, including blood vessels and optic nerve disks.

Findings of Diagnosis

For a person suffering from Hypertensive Retinopathy, this examination is likely to show:

Constriction of the arterioles.

Changes in the walls of retinal blood vessels.

Flame-shaped hemorrhages in the retina.

Yellow and hard exudates.

Spots in the shape of cotton wool.

Swelling of the optic disc.

Treatment

The primary treatment for Hypertensive Retinopathy is controlling blood pressure of the eyes. Some lifestyle changes like reducing the intake of salt, avoiding tobacco, etc., may bring down or control systemic hypertension in the eyes. In many cases, doctors may just recommend lifestyle modifications. Nevertheless, it completely depends on the extent of the damage and whether or not there is any fluid accumulation.

If the doctor feels that lifestyle modification is not enough, he may go for medicines that help the patients to control blood pressure effectively.

If the problem is in advanced stages and there is fluid accumulation behind the retina, the doctor may go for Intravitreal injection or Laser Therapy to control the edema.

Conclusion

Eyes are one of the most significant part of the body, this is why it is important for people to take care of it. In case of disease like Hypertensive Retinopathy, one must consult a doctor before opting any treatment or medicines.

Hypertensive Retinopathy - Everything About It!

Glaucoma is a disease that damages your eye's optic nerve. It usually happens when fluid builds up in the front part of your eye. That extra fluid increases the pressure in your eye, damaging the optic nerve.Glaucoma is the second largest cause of eye blindness in the world.

There are several types of Glaucoma:
1. Open-angle Glaucoma
2. Normal-tension Glaucoma
3. Angle-closure Glaucoma
4. Congenital Glaucoma
5. Secondary Glaucoma
6. Glaucoma suspect

How will you know that you are suffering from Glaucoma?
Only half the people with glaucoma are aware that they are suffering from this condition. When Glaucoma develops, there are usually no early symptoms. This is why glaucoma can 'steal' sight gradually.

Symptoms:
1. In its early stages, open-angle Glaucoma has no obvious symptoms. As the disease progresses more blind spots develop in the peripheral (side) view.
2. An attack of angle-closure Glaucoma includes the following:
a. Severe pain in the eye or forehead
b. Redness of the eye
c. Decreased vision or blurred vision
d. Vision rainbows or halos
e. Headache
f. Nausea
g. Vomiting
If you get any of the symptoms rush to your doctor and take an eye exam as soon as possible.

Causes:
1. Eye injury
2. Inflammation of the eye
3. Dilating eye drops
4. Blocked or restricted drainage in your eye
5. Use of steroid-containing medications (pills, eye drops, sprays)
6. Poor or reduced blood flow to your optic nerve
7. High or elevated blood pressure

Who is at Risk for Glaucoma?
People with more risk of developing Glaucoma include people who:
1. Are over age 40
2. Have family members with glaucoma
3. Have high eye pressure
4. Are farsighted or nearsighted
5. Have had an eye injury
6. Have diabetes, migraines, high blood pressure, poor blood circulation or other health problems affecting the whole body.

Types, Causes and Symptoms of Glaucoma

An inflammation resulting in the formation of a thin layer inside the eyelids or the white part of the eyeball is known as pink eye or conjunctivitis. This condition turns the eye ball into pinkish color, hence the name. Based on the severity of the infection, either one or both eyes get affected.

What are the common symptoms?

Medium to heavy swelling of the eye
Eye crusting after sleep
A burning sensation
Irritation, itching or blurred vision
Redness and increased sensitivity of the eye
Different kinds of conjunctivitis:

Allergic Conjunctivitis: This is the type of conjunctivitis that results from eye irritants such as animal dander, dust particles and pollen. This is not infectious in nature. Treatment prescribed by ophthalmologist includes eye drops and non-steroidal medications. It is advised to keep the eye moist till it gets cured.
Viral Conjunctivitis: As the name suggests, this kind of conjunctivitis is caused due to a viral attack. Sadly though, antibiotics don t work and there is no particular medication for this type of conjunctivitis. Like common cold, viral conjunctivitis runs its course in a span of 1-2 weeks. Since virus is contagious, it is necessary to ensure that the microbes don t spread. Some common prevention measures are listed below:
Eye cosmetics should be abandoned till the conjunctivitis is cured
Hands should be frequently cleaned
Hand and eyes should not be in contact
Frequent change of pillow covers, towels and clothes
Swimming should be completely avoided
Spectacles in place of lens should be used until advised otherwise by a medical practitioner
Bacterial Conjunctivitis: This kind of conjunctivitis is caused by the streptococcal bacteria and has potential to cause real damage if proper medication is not taken on time. This is highly contagious. Prescription often includes antibiotic drop and ointments. The medication is prescribed for 2-3 weeks depending on the level of bacterial spread in the eye. It is very essential to complete the full course of medication to avoid recurrence. Prevention measures as stated above should be strictly followed.
Chemical conjunctivitis: Eye irritants such as chlorine cause this conjunctivitis. Frequent swimmers often get affected by this type of eye infection. Topical steroids are prescribed to cure this kind of infection. Immediate medical attention is required to avoid lasting injury to the eye.
How to prevent pink eye?
While prevention is the best way to refrain from conjunctivitis, some basic hygiene checks are very important. Here is a list of must do s:

Do not share personal items such as combs, towels and toiletries.
Stay away from a conjunctivitis infected patient
Using of goggles while swimming
Frequent usage of hand sanitizer and hand wash

Pink Eye - How You Can Prevent It

A common headache can have a number of reasons behind it, such as defective vision, hetrophoria or convergence deficiency, etc. Now, the question arises as to how they can cause headache. Read on to know more...

Q. Why should defective vision cause headache?

To attain a perfect vision, eyes with defective vision have to make sustained extra efforts, which results in headache. Even if the refractive error is very small, it can be the cause of headache. More prolonged the working and smaller the print, higher the incidence of headache.

Q. Can this occur at all ages?

Yes, it can occur at all ages. However, with age, the resistance decreases and hence elderly people are more prone to get headache. More the use of computer, mobiles, TV or prolonged studies precipitates headache

Q What is Hetrophoria?

Normally, both eyes always remain parallel, but in some cases, eyes have slight tendency to develop minor squint, may be convergent or divergent. This is called Hetrophoria or Latent squint. Such patients have to take extra strain to keep the eyes straight

Q. What is convergence deficiency?

For reading, both eyes have to converge and if there is weakness of convergence, extra strain has to be put on the eyes, which cause headache.

Q. What is the ideal method of refraction in young patients, I,e below 40 years?

Ideal method is to dilate the pupil with Tropicasyl plus drops. This has the advantage that the doctor can see the retina and Optic Disc. This is important to exclude any involvement of brain as the cause of headache. It also relaxes accommodation and hence provides correct refraction. In cases of Hypermetropia, it is extremely essential to dilate the pupil.

Q. What is the role of Autorefractmeter (a computer) in refraction?

It is a very important instrument to provide correct refraction, but it cannot be totally relied upon. Some opticians rely on it and give wrong numbers.

Q. What is acceptance Test?

You have refracted the eyes with Autorefractmeter or Streak Retinoscope but exact power is what a patient accepts. This is very important.

Q. What is astigmatism?

There is a difference in refraction in different meridians and it is important that a cylinder number is prescribed in correct axis. This is a difficult task and needs lot of experience.

Q. Is it important to correct astigmatism?

To relieve headache and strain on the eyes, it is very important that exact cylinder is prescribed.

Q. What is the role of exact centring of Optical Lenses?

You may give correct number, but if the centre of the Optical lenses and cornea do not coincide, satisfactory results are not obtained. To dispense correct lenses is a big art and the Optician must be qualified and well experienced.

Q. Does the quality of lens affect the visual comfort?

Yes, it is important that quality of lenses should be good, preferable fibre lenses which are Ant reflect coated. Crizal coating with capability to block the UV rays are very popular.

Conclusion: Refractive errors are important cause of headache and needs proper examination of the eyes, preferably after dilating the pupil. Astigmatic error even if too small may be the cause of headache. Spectacle dispensing is an art and a patient must select proper optician. Spectacles if advised for constant use must be used constantly to get full relief.

Defective Vision - Can it be a Cause of Your Headache?

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