Ho Optometrist

Your Local Optometrist from 怡保……Ipoh….. Perak, Malaysia

Headache, neck pain, blurry eyes after Computer use?? READ THIS…

Computer vision syndrome (CVS) is a temporary condition resulting from focusing the eyes on a computer displayfor protracted, uninterrupted periods of time.

Some symptoms of CVS includes:

    • Headaches,
    • Blurred vision,
    • Neck pain,
    • Redness in the eyes,
    • Fatigue,
    • Eye strain,
    • Dry,
    • Irritated eyes,
    • Double vision,
    • Polyopia,
    • and difficulty refocusing the eyes.

These symptoms can be further aggravated by improper lighting conditions (ie. bright overhead lighting or glare) or air moving past the eyes (e.g. overhead vents, direct air from a fan).

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Color Blind Test…… Do u see color?

Color Blind Testing:

This is a test for colour blindness or to use a better but less common term, colour vision deficiency. Most so-called “colour blind” individuals are not truly colour blind but instead have abnormal colour vision. They only have problems distinguishing certain colours and shades of the same colour. They do not see only in black and white. True inability to distinguish any colours is actually rare.

Understanding more about color blindness

It is estimated that eight percent of males and fewer than 1 percent (about 1 in 200) of females are colour deficient. Most people suffering from colour blindness are born with the condition. They inherit the condition from their parents as an ‘X-linked trait’. This means that the gene causing the condition is located on the X sex chromosome. Males have an X and a Y sex chromosome, while females have a pair of X sex chromosomes.

How color blindness is inherited from a mother with a recessive mutated X chromosome
Genetically, this means
  1. Males are predominantly affected.
  2. Females are not predominantly affected but are carriers of the defective genes. Carriers carry the gene and can pass it on to half their sons. Half their daughters can be carriers. Carriers themselves are not affected by the defect.
  3. If the father is colour blind, all his daughters will be female carriers of the defective genes. All his sons will be spared.
  4. If the mother is colour blind, all her sons will be affected and all her daughters will be female carriers.

Green colour weakness or blindness is most common, followed by red colour weakness or blindness. It is important to remember that not all cases of colour blindness are congenital as there are some diseases acquired later in life, like diabetic eye disease, glaucoma, retinal or optic nerve disease which may disrupt colour vision.

Color Blindness from Diseases

There are a number of inherited diseases that can lead to color blindness, fortunately they are quite rare but are all eye specific illnesses, they include:

  • Cone Dystrophy
  • Cone-rod Dystrophy
  • Achromatopsia
  • Blue cone monochromatism
  • Retinitis pigmentosa
  • Macular Degeneration
  • Retinoblastoma
  • Leber’s congenital amaurosis

There are some additional, better known chronic illnesses that are said to sometimes cause color blindness. Whether or not these illnesses can cause someone to become color blind is of questionable validity as there are very few documented cases. The list includes:

  • Alzheimer’s disease
  • Diabetes mellitus
  • Glaucoma
  • Leukemia
  • Liver disease
  • Multiple sclerosis
  • Parkinson’s Disease
  • Sickle cell anemia
  • chronic alcoholism

The importance of color vision testing

It is important to know if you are colour blind. Colour is often used as an aid to teaching in pre-primary and primary schools. Children who have difficulty distinguishing between colours may be misdiagnosed as having learning difficulties unless it is known beforehand that they have a colour vision defect. Knowing the existence of a colour vision defect early can thus help prevent communication problems in school and in later adult life.

Schoolchildren with colour vision defect should think over carefully before choosing study subjects where colour discrimination is important. Art and chemistry are two examples of such subjects.

Consider colour deficiencies when making career decision. This is because many occupations demand good colour discrimination. Defective colour vision is a handicap in some pharmacy and chemistry jobs. Colour is often used to convey important information such as in traffic and navigational lights and colour coding of electrical wires.

How we see color

Our eyes are capable of differentiating an infinite array of colours. Yet, would you believe that all our colour sensations are actually derived from varying stimulation of only three types of colour receptors, namely red, green and blue?

These receptors, called cones, are found solely in the centre part of the retina in an area called the macula. The retina is the nerve layer lining the back of the eye, much like the film in a camera.

The colours red, green and blue are also known as the primary colours. A suitable mixture of these three colours can produce any colour including white!

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Did You Know? – Glaucoma

Did You Know?
Did you know that you could be going blind and not even know it? That’s what glaucoma does. It sneaks up on you gradually. Glaucoma is one of the leading causes of blindness in the world. It affects 60.5 million people today and is set to reach 79.6 million by 2020.

If you have a family history of glaucoma, you’re at high risk. Glaucoma can’t be cured, but it can be controlled and the risk of blindness reduced-if glaucoma is detected and treated in time.

Get your eyes examined. Don’t lose sight of glaucoma.

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Free Glaucoma Screening at Ho Optometrist

In conjunction with World Glaucoma Week, Ho Optometrist are providing Free Glaucoma Screening to the public from 10th March 2012 till 10th April 2012. Our practice welcomes the community of Ipoh to drop by for a Glaucoma Screening.

For more information, please contact us through email at ho_optometrist@yahoo.com or call us at 05-255 9185 during business hours.

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Five Common Glaucoma Tests…

Early detection, through regular and complete eye exams, is the key to protecting your vision from damage caused by glaucoma.

It is important to have your eyes examined regularly. Your eyes should be tested:

  • before age 40, every two to four years
  • from age 40 to age 54, every one to three years
  • from age 55 to 64, every one to two years
  • after age 65, every six to 12 months

Anyone with high risk factors, should be tested every year or two after age 35.

A Comprehensive Glaucoma Exam

To be safe and accurate, five factors should be checked before making a glaucoma diagnosis:

Examining… Name of Test
The inner eye pressure Tonometry
The shape and color of the optic nerve Ophthalmoscopy (dilated eye exam)
The complete field of vision Perimetry (visual field test)
The angle in the eye where the iris meets the cornea Gonioscopy
Thickness of the cornea Pachymetry

Regular glaucoma check-ups include two routine eye tests: tonometry and ophthalmoscopy.

Tonometry

Tonometry measures the pressure within your eye. There are 2 different types for this test, which is the contact- tonometry (Goldmann Tonometry) and the non contact (air-puff) tonometry.

During contact tonometry, eye drops are used to numb the eye. Then a doctor or technician uses a tool called a tonometer to measure the inner pressure of the eye. A small amount of pressure is applied to the eye by a tiny tool or by a warm puff of air.

As for non-contact or air puff tonometry uses a special intrument that puffs air to the eye, measuring the inner pressure of the eye.

The range for normal pressure is 12-22 mm Hg (“mm Hg” refers to millimeters of mercury, a scale used to record eye pressure). Most glaucoma cases are diagnosed with pressure exceeding 20mm Hg. However, some people can have glaucoma at pressures between 12 -22mm Hg. Eye pressure is unique to each person.

 Ophthalmoscopy

This diagnostic procedure helps the doctor examine your optic nerve for glaucoma damage. Eye drops are used to dilate the pupil so that the doctor can see through your eye to examine the shape and color of the optic nerve.

The doctor will then use a small tool with a light on the end to light and magnify the optic nerve. If your intraocular pressure is not within the normal range or if the optic nerve looks unusual, your doctor may ask you to have one or two more glaucoma exams: perimetry and gonioscopy.

Perimetry

Perimetry is a visual field test that produces a map of your complete field of vision. This test will help a doctor determine whether your vision has been affected by glaucoma. During this test, you will be asked to look straight ahead and then indicate when a moving light passes your peripheral (or side) vision. This helps draw a “map” of your vision.

Do not be concerned if there is a delay in seeing the light as it moves in or around your blind spot. This is perfectly normal and does not necessarily mean that your field of vision is damaged. Try to relax and respond as accurately as possible during the test. Your doctor may want you to repeat the test to see if the results are the same the next time you take it. After glaucoma has been diagnosed, visual field tests are usually done one to two times a year to check for any changes in your vision.

Gonioscopy

This diagnostic exam helps determine whether the angle where the iris meets the cornea is open and wide or narrow and closed. During the exam, eye drops are used to numb the eye. A hand-held contact lens is gently placed on the eye. This contact lens has a mirror that shows the doctor if the angle between the iris and cornea is closed and blocked (a possible sign of angle-closure or acute glaucoma) or wide and open (a possible sign of open-angle, chronic glaucoma).

Pachymetry

Pachymetry is a simple, painless test to measure the thickness of your cornea — the clear window at the front of the eye. A probe called a pachymeter is gently placed on the front of the eye (the cornea) to measure its thickness. Pachymetry can help your diagnosis, because corneal thickness has the potential to influence eye pressure readings. With this measurement, your doctor can better understand your IOP reading and develop a treatment plan that is right for you. The procedure takes only about a minute to measure both eyes.

Why Are There So Many Diagnostic Exams?

Diagnosing glaucoma is not always easy, and careful evaluation of the optic nerve continues to be essential to diagnosis and treatment. The most important concern is protecting your sight. Doctors look at many factors before making decisions about your treatment. If your condition is particularly difficult to diagnose or treat, you may be referred to a glaucoma specialist. A second opinion is always wise if you or your doctor become concerned about your diagnosis or your progress.

Source:

http://www.glaucoma.org/glaucoma/diagnostic-tests.php

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Douglas MacMillan writes,

“To err is human. But to persevere is a feat that often separates the successful from the mediocre.”

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什么是青光眼?

青光眼是因「眼壓過高」,使視神經受傷而導致視野缺損的一種眼疾。然而,究竟眼壓要多少才算是「正常」呢?一般人眼壓的平均值約在12~21mmHg,但因為每個人的視神經所能承受的壓力值差異相當大,所以更適當的定義是:一個人的眼壓,只要會使他的視神經受傷,造成視野缺損,則不論數值多少,都屬於眼壓過高,亦即有青光眼的發生。

青光眼是一種可能導致失明的眼部疾病,在患病初期通常可以經由控制使病情不再惡化,但因常無症狀表癥而被忽略,所以最好的診斷方式就是定期地做眼部檢查。青光眼通常是由於眼壓過高傷害視神經,使得視神經的訊息無法順利傳達到腦部所造成。而青光眼又可分為二類:開放性青光眼及閉鎖性青光眼。

眼睛的檢查 早期發現青光眼的最佳方法便是定期做眼睛的檢查。眼科醫師會用一些特殊的設備來測量你的眼壓、檢查眼球中的引流區及視神經,還會檢查你的視野範圍(眼睛可看到的範圍)以確定你是否喪失周邊的視野。 有些眼藥水可用來擴張你的瞳孔以幫助醫師更仔細地觀察你的眼睛 。

哪些人是青光眼的高危險群?

每個人都有可能會得到青光眼,但某些帶有危險因子的人的確有較高的罹患率。這些危險因子包括:

  • 年齡的增加
  • 非洲黑人
  • 有青光眼家族病史者
  • 眼睛曾經受過傷害或接受過手術者
  • 其他疾病亦有可能會造成青光眼,如:糖尿病、高血壓

青光眼的治療

青光眼的治療可以預防或限制視野的喪失,主要目標為降低患者的眼壓。醫師會採用最適合你的治療方式,你只需要比平時更密切地檢查或接受適當的藥物及療程即可。

降眼壓藥物

某些眼藥水或藥物可用來降低你的眼壓。有些藥物可降低房水的製造量,另有些藥物則加速排除眼內的房水,你必須按照醫師的指示來使用這些藥物,不要任意停藥 — 即使你覺得症狀已獲得改善,因為眼壓有可能突然地就快速上升而危及你的視力。任何因藥物引起的副作用,都要記得告訴醫師。

青光眼的控制

確實按照處方服藥,絕對不要未與醫師討論就擅自停藥。

http://www.libertytimes.com.tw/2008/new/mar/6/today-life7.htm

http://www.msd.com.tw/content/patients/glaucoma.html

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