Angioid Streaks

What are Angioid Streaks ?

Angioid streaks are broad, irregular, red to brown to grey lines which radiate from the area around the optic nerve head under the retinas of individuals with pseudoxanthoma elasticum (PXE). These streaks or striations are typically bilateral and vary in width from 50 to 100 microns, barely detectable by ophthalmoscopy, to 3-4 times the average retinal vascular width, dramatically visible to the casual ophthalmic observer. Their borders are irregular, serrated, and occasionally ill-defined, particularly when they are smaller than the blood vessels in that region. Their number and extent are variable, as are their age of onset. Their course tends to be more sinuous and angular than normal retinal blood vessels.

The first description of angioid streaks was provided in 1889 by Dr. Robert W. Doyne, an English ophthalmologist. He reported a male who had received injuries to both eyes: "In all directions throughout the choroid of both eyes, especially around the discs, are irregular, jagged lines, nearly all deeply pigmented . . .". "The irregularities and jags in their outline exactly correspond in most places and are probably due to rupture of the pigment layer of the retina . . .".

Dr. Herman J. Knapp, a German-born American ophthalmologist, who coined and introduced the term "angioid streaks" in 1892, felt that they represented "the conversion of extravasated blood into streaks of dark brown or black pigment in the retina . . ." .

Subsequently, in 1929, Groenblad, also an ophthalmologist, related the occurrence of angioid streaks with Pseudoxanthoma Elasticum, in the same year as Strandberg described them independently.

The reported frequencies of angioid streaks in pseudoxanthoma elasticum vary tremendously with the era of the observer, the specialty (dermatology, genetics, ophthalmology, etc.), and the diligence with which individuals and all family members are scrutinized. At least 50% of all individuals with PXE demonstrate angioid streaks. However, that "prevalence rate" typically reflects a "single encounter" and does not reflect the analysis of diligent observations of individuals with PXE followed sequentially over years and decades.

Are angioid streaks present at birth?

Angioid streaks are not present in newborns or infants but, in some individuals and families can, be identified before the age of 10 years. Retinal fundus photography documents their appearance and serves as baseline for future observations. Retinal fluorescein angiography will enhance recognition of the angioid streaks, because they are typically hyperfluorescent wherever the retinal epithelium is thinned or atrophic, thereby permitting their ready recognition in the contrast-enhanced presentation of monochromatic photography.

How are they caused?

Just as the pathogenesis of PXE in the skin, gastrointestinal system, and cardiovascular systems is unknown, so the pathogenesis of angioid streaks is similarly in much debate. The best current information suggests a defect in elastic fibres, particularly in Bruch's membrane, the elastic layer between the retinal pigment epithelium and the choroid.

Histopathology shows premature basophilia and staining with increased amounts of calcium and iron, much as seen in older eyes in general. Both thinning and thickening of the basement membrane and Bruch's membrane are noted under the retinal pigment epithelium. The streaks present as ruptures in this elastic lamina of Bruch's membrane.

Are angioid streaks associated with other medical conditions?

Angioid streaks are seen in a number of clinical disorders in addition to Pseudoxanthoma Elasticum: sickle cell anaemia, thalassemia, Paget's disease of bone, acromegaly and other pituitary disorders, and familial hyperphosphatemia. Occasionally, angioid streaks are noted with "no other disease", but they have also been seen in younger individuals with PXE who have no (current) cutaneous manifestations of the disease but develop them later. Therefore, the presence of angioid streaks should be considered indicative of an underlying systemic illness, even if the specific disorder cannot be identified or defined accurately at the time that the angioid changes are first noted. The patient must remain under continuing surveillance. How are angioid streaks diagnosed ?

The most common retinal feature associated with angioid streaks is the presence of "peau d'orange", a mottled fundus appearance which classically precedes the appearance of the streaks. The French term persists as a description of the fine, relatively symmetrical, drusen-like, flat, yellow, and occasionally confluent lesions in the retinal pigment epithelium, extending throughout the posterior pole and out to the equator. Peau d'orange does not affect visual acuity, even when the fovea is involved. However, when readily identifiable in one individual, siblings and parents should be investigated for the presence of peau d'orange even in the absence of angioid streaks.

Other retinal changes in association with peau d'orange and angioid streaks include focal hemorrhages with or without scarring, salmon patches (which typically represent a healing subretinal hemorrhage), black dots, (the result of metaplasia of the pigment epithelium following focal or blot hemorrhages), and "pearls" (dead white or yellow-white foci typically 150-300 microns in size, again representing either the result of subretinal hemorrhage, subpigment epithelial hemorrhage, or a focal disciform scar with spontaneous resolution). Occasionally, peripheral hemorrhages under the retina, near the ora serrata, may evolve to discoid metaplasia of the retinal pigment epithelium simulating disciform degeneration.

Intrapapillary drusen, or drusen of the optic nerve head, have been seen in some individuals and in some families, typically but not universally with dominantly inherited PXE. The usual complications of intrapapillary drusen including juxtapapillary bleeding, juxtapapillary disciform disease, visual field deficits, and even advanced visual impairment, can occur in this association.

The most visually devastating complication of angioid streaks and peau d'orange is disciform degeneration of the central visual area. The mechanism of disruption of the pigment epithelium-Bruch's membrane barrier and the invasion of new blood vessel under the retina is not different from other causes of disciform disease. Historical initial attempts to apply laser photocoagulation with either green or red wavelengths met with limited success, giving laser treatment for this complication a variable and poor outlook. More recent technologies, to identify fully the extent of neovascular membranes with sequential fluorescein angiography and rapid retreatment of recurrences, have yielded a better outcome in many individuals. However, the risk of recurrence is real, presumably because of the widespread defects in the pigment epithelium Bruch's membrane interface.

Other historical references to visual impairment in PXE from "choroiditis" or "chorioretinitis" are probably misinterpretations of the disciform process. Occasional older individuals with peau d'orange and angioid streaks will develop geographic atrophy of the retinal pigment epithelium, simulating "central areolar choroidal sclerosis" and sometimes (incorrectly) called "age-related macular degeneration".

Individuals with PXE also have systemic vascular disease involving large arteries, such as the carotid artery in the neck. For this reason, they may have a slightly higher risk than the general population for retinal vascular occlusive disease and non-arteritic ischemic optic neuropathy.

Other historical ocular complications of PXE include "blue sclerae" and vulnerability to global rupture. These case reports are probably misinterpretations and misdiagnoses of osteogenesis imperfecta, a different connective tissue disorder, since no valid description of these associations has appeared in the last 15 years of ophthalmic and genetic literature. Although angioid streaks are listed historically as complications of the Ehlers-Danlos syndrome, those reports are also probably due to a misdiagnosis of PXE by a different eponym.

All individuals with angioid streaks, and especially all individuals with PXE, should undergo a diligent, complete ophthalmologic examination and annual surveillance for ocular complications of this disorder.

Cataracts

Cataract develops when the lens of the eyes become opaque or cloudy and starts to affect vision. The lens of the eyes should always be transparent but once cataract is developed, the lens becomes similar to ‘frosted glasses'. Cataract could blur the patient's vision or it can lead to complete blindness of the infected eye.

This condition is very common for the elderly as it develops gradually changes he shape and structure of the lens through age. Cataracts can be treated by a day case surgery which involves the removal of the infected lens. Artificial lenses replace the infected lens. Cataract is causes blindness for a majority of cases especially in countries where the surgical innovations for this condition is still not available.

Mechanism of sight

When a person looks at an object, the light emanating from the object goes to the cornea and then to the lens. After that, light goes to the retina which is found at the back of the eye.

The lens focuses the majority of light from the eye to the macula which makes up a portion of the retina. The macula is full of ‘seeing cells' or the rods and the cones.

The nerve signals go through the rods and cones until it reaches the optic nerves that go straight to the brain. The brain then interprets the signal and allows us to see.

To effectively enable us to see, the lens should be transparent and clear.

Different types of cataract

* Senile cataract. This is also known as age-related cataract and affects the majority of elderly people. People who are sixty years old and above are at high risk of developing this condition. In UK, one out of three old people are afflicted with cataracts. Both sexes have equal chances of acquiring the condition. Majority of the cases would involve both eyes but only one eye would get the worse cataract build up. This type of cataract gradually develops as age progresses. Patients with early cataract may not realize that they have the condition because the cloudiness does not affect their vision severely. Some cases of cataract do not worsen over time but for some patients, it will go on and cause complete blindness.

o Causes of senile or age-related cataract. The exact mechanism of what causes this type if cataract is still not clear but some suggest that there must be a change in the structural proteins of the lens. The change can be a result of an impairment or disturbance in the pathway of the nutrients and fluids as they are being transported to the lens. Age can affect this pathway as well as proteins would clump in discreet places inside the lens. These clumps cause the cloudiness in the lens and these areas block the light from getting to the retina. The degree of severity depends largely on the amount or number of clumping areas which cause cloudiness in the lens. Aside from age, people with smoking habits, poor diet, overexposure to ultraviolet light, steroid medicines, and diabetes. People who have a family history of the condition are at high risk of developing cataract.

o Symptoms for senile cataract. The first symptoms would include blurring of the patient's vision. Next is the noticeable ‘spots', then seeing halos surrounding bright lights. The patient may not be able to see well in the sunlight or become easily dazzled with car headlights. After these first symptoms, the severity of the cataract would become worse and would lead to blindness.

o Diagnosis for senile cataract. An eye specialist for cataracts is called an optometrist and he will examine the eyes of the patient. Consultation can be done because the patient is wary about his blurred vision or can it can also be just a routine eye check-up.

o Treatment for senile cataract. If a person is diagnosed with early cataract, he may not notice any problems in their vision. The rate of deterioration is different per person and some patient would not require treatment because their vision is normal. But consulting a doctor should be done either way as it could affect your life. Seeking treatment is subjective to the patient but should be an option for all. Cataract can affect the patient if the vision is also affected. You cannot do normal chores such as driving, watching TV, reading, studying or even taking care of yourself. The treatment interventions are usually very successful but some people would tend to develop minor complications. It is always a good idea to have regular eye check-ups to ensure that no eye complication is being developed in your system.

Infected lenses with cloudiness are replaced by artificial plastic lenses in an operation called the intraocular implant. In the UK, Phaco Extracapsular Extraction or Phacoemulsification is the most common operation done. This operation entails the removal of the infected lens as well. This operation takes about ten to thirty minutes and is often called a ‘day case'.

In Phaecoemulsification, a local anesthetic is given to the patient so he will remain awake throughout the entire operation. But fortunately, this operation is not painful because the anesthetic in the form of eye drops will numb your eyes. Other than eye drops, local anesthetic injections can also be used in the eye. Once the eyes are numb, the eye surgeon would create a small hole in the corneal region. After this, a small instrument is inserted inside the lens, just near the front portion of the lens capsule. The small instrument gives out ultrasound waves to break the lens contents inside the capsule. Once the components are broke, it is suctioned out by a needle. After removing the lens materials, the transparent plastic lens is inserted inside the capsule via the initial hole made in the front portion of the cornea. The posterior portion of the capsule remains attached so that the plastic lens is kept well in place. In some cases, plastic lenses are not used; instead glasses or contact lenses are used to imitate the role of the lens.

There are other surgical techniques that can treat cataract aside from phaecoemulsification. There is a technique called the manual extracapsular extraction wherein the surgeon makes a longer cut in the corneal side. The surgeon then takes out the center or focal point of the lens without breaking the contents using ultrasound waves. The posterior or back portion of the capsule if kept in place. The plastic lens is then put in place of the extracted lens. Aside from manual extracapsular extraction, there is another technique called the intracapsular extraction where the entire lens is extracted, along with the capsule. After the removal of the lens and capsule, plastic lens or glasses are placed in to imitate the role of the lens in the eye. This technique is rarely done in UK because it presents more risks and complications than the previously mentioned surgical techniques. But for less privileged countries, intracapsular extraction is still being done because the technology needed to perform modern treatment is still not available.

o Complications of surgery. Surgery for cataract is usually successful and it improves the vision immediately. But in some cases, complications like infection, inflammation and damage to the cornea and other eye parts, and bleeding can happen. These side effects are very rare and can be treated immediately. But for some, this can lead to permanent visual impairment.

Aside from these complications, posterior capsule opacification or simply called cloudiness can also arise after surgery. This complication happens after pahecoemulsification and manual extracapsular extraction. These procedures require keeping the posterior portion of the capsule intact after the operation. Often, this portion would thicken months after the operation. This results in the cloudiness of the lens which would affect the vision of the patient. This is treated using painless laser surgery. The laser burns a small hole in the central portion of the capsule to allow light to come in and restore vision.

* Congenital cataract. This is a rare case but very important to be diagnosed as early as possible. Vision is learned at an early stage during infancy and should a cataract be present at birth, it would block the eyes from learning and establishing the correct visual pathway. This can result to blindness which can persist even after the cataract is removed. Doctors examine the eyes of the babies to check for this condition and prevent blindness later in life.

* Other types. Cataract can also develop from an eye injury or from radiation damage due to overexposure. Cataract can also occur as secondary or comorbid problem if the patient has some serious eye complications or diabetes.

Far sightedness

Hyperopia, also known as far-sightedness, long-sightedness or hypermetropia, is a defect of vision caused by an imperfection in the eye (often when the eyeball is too short or when the lens cannot become round enough), causing inability to focus on near objects, and in extreme cases causing a sufferer to be unable to focus on objects at any distance. As an object moves toward the eye, the eye must increase its power to keep the image in focus on the retina. If the power of the cornea and lens is insufficient, as in hyperopia, the image will appear blurred. Hyperopia, and restoring of vision with convex lens.

People with hyperopia can experience blurred vision, asthenopia, accommodative dysfunction, binocular dysfunction, amblyopia, and strabismus.[1]

Hyperopia is often confused with presbyopia,[2][3] another condition that frequently causes blurry near vision.[4] Presbyopes who report good far vision typically experience blurry near vision because of a reduced accommodative amplitude brought about by natural aging changes with the crystalline lens.[4] It is also sometimes referred to as farsightedness, since in otherwise normally-sighted persons it makes it more difficult to focus on near objects than on far objects.[5]

Short sightedness (Myopia)

In order to see, the light rays that come from an object pass through one's eyes to the retina. The nerves in the retina then send impulses to the brain via the optic nerve, allowing us to “see”.

If the light rays are not focused on a particular part of the retina, the image seen will so blurred and fuzzy. Focusing is actually the function of the lens and cornea. The cornea refracts light rays while the lens makes focusing adjustments via changes in its thickness. Such adjustment is referred to accommodation. The human lens can actually become more rounded or flatter because of its elastic qualities. To allow more light rays bent inwards, the lens become more rounded. Changes in the lens' shape are controlled by the small muscles located in the ciliary body attached to the lens.

Refraction or bending of light rays allows focusing of near objects while objects that are far away require less bended light during focusing.

What happens during short-sightedness?

An individual who is short-sighted will have difficulties seeing objects clearly at a distance since the light rays will be focused at retina's front. Despite maximum lens flattening, the eyes will still have difficulties focusing the light rays more at the back. This will just affect objects which are being viewed at a distance and not the near ones since the light rays will come straight into the eyes. For near objects, the light rays usually go slightly upwards.

Causes of Short Sightedness

Individuals who are short-sighted usually have long eyeballs, with the distance to the retina from the lens farther than normal. Being short-sighted is fairly common and can even be inherited.

Symptoms of Short Sightedness

In most cases, vision problems begin during the teenage years and in rare cases, even earlier. Severity of the condition will usually be dependent on when the symptoms were first experienced. As soon as the person hits adulthood, the condition stabilizes.

Complications of Short Sightedness

There are no known problems associated with short sightedness although individuals who are myopic are at higher risk for macular degeneration, detached retina and glaucoma, which are more serious eye conditions. In order to prevent myopic from progressing into these eye problems, regular eye examinations are recommended as well as reporting of any new symptoms.

Treatment for Short Sightedness

There are several treatment options available for individuals suffering from myopia. Among them are:

* Glasses – this is the most common and simplest treatment. Because of their concave lens, glasses could easily bend light rays outwards slightly. Thus, the light rays are able to bend back further in the retina as it goes through the lens and cornea allowing for better focusing.

* Contact lenses – provides similar results as glasses.

* Surgery – another option that is gaining popularity in recent years. There are presently different types of surgical operations designed to treat short sightedness. The most popular of which is the LASIK or laser-assisted in situ keratomileusis. This procedure involves removal of a portion of the cornea using a computer-guided laser resulting to a flatter cornea and allowing for the light rays to be focused further back. So far, treatment with this technique is quite effective and many myopic individuals choose this option especially since the result is instant and the procedure is virtually pain-free.

However, caution is given for those undergoing surgical procedure to correct myopia or short sightedness since there are certain complications. For instance, some individuals will experience hazy vision. Also, the vision may just be improved and the individual will still require glasses in order to see clearly.

For this reason, it is important that you are aware of all the information including complications, failure rate and cost in order to make an informed decision. Do not hesitate to ask questions.

Online Eye Test

There are a few tips that should make the exam more accurate:
1) have someone measure out the correct length that you should sit back at
2) keep a 1/4" black border around your screen monitor by using the monitor buttons
3) try not to squint
4) when you can no longer read more than half the words on a line, press stop

A word of advice:
1) do not consider this as an official exam, only an optometrist has the most precise instruments to find your true Rx
2) this exam is only meant to give you an idea of where your eye power lands
3) due to variations in every monitor, accuracy is not perfect (dot pitch, brightness/contrast, monitor size, screen size, screen resolution)

Starting at just $180, we have glass & frame packages to suit anyone.

We will match any offer from a local competitor on a similar stocked product.

Ross Brown optometrist is Shop 32 located near the eastern entrance of Lakehaven Drive.