Occuvision and Covid-19

Everyone is concerned about minimising their exposure to, and the spread of, SARS-CoV2. And rightly so.

You limit your contact with others and sanitise everything you touch. But work and life must continue as much as possible at the same time.

We get it. Please watch this short Health & Safety message from our Managing Director.

 

We also use UV-C sanitisers like this one on site to prevent spread.

Contact us to find out more

Glaucoma

Introduction

Glaucoma is a nerve disorder of the eye, damaging the optic nerve and causing a loss of vision. Increased pressure in the eyeball is often associated with glaucoma.

Both the anterior and posterior chambers of the eye are filled with a thin fluid called the aqueous humor. The fluid is produced in the posterior chamber, passes through the pupil into the anterior chamber, and then drains from the eye through the outflow channels. If the flow of fluid is interrupted, usually by an obstruction that prevents the fluid from flowing out of the anterior chamber, pressure increases.

Usually, glaucoma has no known cause, but can be brought on by some medications (cortisone) and diseases (diabetes mellitus). The risk also increases with age (40+) and genetics (family history of glaucoma). If the outflow channels are open, the disorder is called open-angle glaucoma. If the channels are blocked by the iris, the disorder is called closed-angle glaucoma.

An ophthalmologist or optometrist can measure the pressure in the anterior chamber by using a simple, painless procedure called tonometry. In general, measurements greater than 20 to 22 millimeters of mercury indicate increased pressure. Occasionally, glaucoma occurs when pressures are normal. Sometimes a series of measurements must be taken over time to determine that the problem is glaucoma. An examination with an ophthalmoscope (an instrument used to view the inside of the eye) may reveal visible changes in the optic nerve caused by glaucoma. Sometimes, the examiner uses a special lens to observe the outflow channels; this procedure is known as gonioscopy.

Glaucoma produces a loss of peripheral vision or blind spots in the visual field. To find out if such blind spots exist, an examiner asks the person to look straight ahead at a central point and indicate when light can be seen. The test may be done either using a screen and pointer or an automated device that uses spots of light.

Open-Angle Glaucoma

The most prevalent form of glaucoma, open-angle glaucoma is common after age 40 but occasionally occurs in children. The condition tends to run in families and is most common in people with diabetes or nearsightedness (myopia).

Symptoms and Diagnosis

Initially, increased pressure in the eyes produces no symptoms. Later symptoms may include narrowing peripheral vision, mild headaches, and vague visual disturbances, such as seeing halos around electric lights or having difficulty adapting to darkness. Eventually, tunnel vision (an extreme narrowing of the visual fields that makes it difficult to see anything on either side when looking straight ahead) may develop.

Open-angle glaucoma may not cause any symptoms until irreversible damage has developed. Usually, the diagnosis is made by checking intraocular pressure. Therefore, every routine eye examination should include a test of intraocular pressure.

Treatment

Treatment is more likely to be successful if started early. Once vision is greatly impaired, treatment may prevent further deterioration, but it usually can’t restore vision completely.

Medicated eyedrops can usually control open-angle glaucoma. Typically, the first eyedrop medication prescribed is a beta-blocker which probably decreases the production of fluid in the eye. Other useful medications work either by improving outflow or decreasing fluid production.

If medication can’t control eye pressure or if side effects are intolerable, an eye surgeon can increase drainage from the anterior chamber by using laser therapy to create a hole in the iris or using surgery to cut out part of the iris.

Safety spectacles

Safety spectacles are intended to shield the wearer’s eyes from impact hazards such as flying fragments, objects, large chips, and particles. Workers are required to use eye safety spectacles with side shields when there is a hazard from flying objects.

Non-side shield spectacles are not acceptable eye protection for impact hazards.

The frames of safety spectacles are constructed of metal and/or plastic and can be fitted with either corrective (Rx) or plano impact-resistant lenses.

Of all staff members identified to wear safety specs, only those needing prescription spectacles for distance or near vision need Prescription Safety Spectacles.

What is so safe about safety spectacles?

Conventional spectacle lens materials, suitable for everyday wear, distort and suffer damage in industrial situations, eg. warpage (and subsequent optical distortion) through constant heat exposure, chipping, scratching, embedding of hot particles in lens surface, etc. They are also unsafe against impact.

The safety lens material of choice is Trivex, an advanced, next-generation polycarbonate derivative – watch the videos.

Why prescription safety spectacles?

  • Conventional spectacle frames do not provide adequate side protection against flying debris.
  • Goggles / safety frames cannot be worn comfortably over conventional specs, due to poor fit or lens fogging.
  • Safety spectacles with prescription clip-in inserts are not suitable for existing multifocal spectacle lens wearers.

We suggest, since Personal Protective Equipment is still company property, a company-funded replacement cycle of 2 years. In case of work-related accident damaging safety spectacles, normal PPE re-issue procedures apply, but cost of replacement through negligent care of safety spectacles is to be borne by staff member.

Contact us to find out more.

Eye injuries

The structure of the face and eyes is well suited for protecting the eyes from injury. The eyeball is set into a socket surrounded by a strong, bony ridge. The eyelids can close quickly to form a barrier to foreign objects, and the eye can tolerate a light impact without damage. Even so, injury can damage the eye and its surrounding structures, sometimes so severely that vision is lost, and in rare instances, the eye must be removed.

Most eye injuries are minor, but because of extensive bruising, they often look worse than they are. Any injury to the eye should be examined by an ophthalmologist (eye doctor) to determine whether treatment is needed and whether eyesight may be affected permanently.

Foreign body eye injuries

The most common eye injuries are those to the sclera, cornea, and lining of the eyelids (conjunctiva) caused by foreign objects. Although most of these injuries are minor, some – such as penetration of the cornea or development of an infection from a cut or scratch on the cornea – can be serious.

Causes of surface injuries include glass particles, wind-borne particles, tree branches, and falling debris. Workers in certain occupations tend to have small particles fly in their faces; these workers should wear protective eyewear. Another common source of surface injuries is the contact lens. Poorly fitting lenses, lenses left in the eyes too long, lenses left in while a person sleeps, inadequately sterilised lenses, and forceful or inept removal of lenses can scratch the surface of the eye.

Symptoms

Any injury to the surface of the eye usually causes pain and a feeling that there’s something in the eye. It may also produce a sensitivity to light, redness, bleeding from the surface blood vessels of the eye, or swelling of the eye and eyelid. Vision may become blurred.

Treatment

A foreign object in the eye must be removed. The ophthalmologist may instil anaesthetic drops to numb the surface of the eye. Using a special lighting instrument to view the surface in detail, he then removes the object. Often the foreign object can be lifted out with a moist sterile cotton swab. Sometimes it can be flushed out with sterile water.

If the foreign object has produced a small, superficial corneal abrasion (scratch), an antibiotic ointment applied for several days may be all the treatment needed. Larger corneal abrasions require additional treatment. Antibiotics are instilled, and a patch is placed over the eye to keep it closed.

Fortunately, the surface cells of the eye regenerate rapidly. Under a patch, even large abrasions tend to heal in 1 to 3 days. If the foreign object has pierced the deeper layers of the eye, the ophthalmologist should be consulted immediately for emergency treatment.

Blunt eye injuries

A blunt impact forces the eye back into its socket, possibly damaging the structures at the surface (the lid, conjunctiva, sclera, cornea, and lens) and those at the back of the eye (retina and nerves). Such an impact may break bones around the eye as well.

Symptoms

In the first 24 hours after an eye injury, blood leaking into the skin around the eye usually produces a bruise (black eye). If a blood vessel on the surface of the eye breaks, the surface will become red. Such bleeding is usually minor.

Damage to the inside of the eye is often more serious than damage to the surface. Bleeding into the front chamber of the eye is potentially serious and requires attention by an eye doctor (ophthalmologist). Recurring bleeding and increased pressure (as a result of the injury) within the eye may lead to blood staining of the cornea, which can reduce vision and increase the life-long risk of glaucoma.

Blood can leak into the inside of the eye, the can be torn, or the lens can become dislocated. Bleeding may occur in the retina, which may become detached from its underlying surface at the back of the eye. Initially, retinal detachment may create images of irregular floating shapes or flashes of light and may make vision blurry, but then vision greatly decreases. In severe injuries, the eyeball can rupture.

Treatment

Ice packs may help reduce swelling and ease the pain of a black eye. By the second day, warm compresses can help the body absorb the excess blood that has accumulated. If the skin around the eye or on the lid has been cut (lacerated), stitches may be needed. When possible, stitches near the edge of the eyelids should be applied by an eye surgeon to ensure that no deformities develop that will affect the way the lids close. An injury affecting the tear ducts (leading from the eye lids to the back of the throat) should be repaired by an eye surgeon.

For a laceration of the eye, pain medications may be given along with medications to keep the pupil dilated and to prevent infection. A shield is often used to protect the eye from further injury. Serious damage may result in some loss of sight, even after surgical treatment.

Anyone who has internal bleeding in the eye caused by trauma is instructed to rest in bed. Medication to reduce increased eye pressure may be needed. Sometimes additional medication is given to reduce bleeding. Any medication that contains aspirin should be avoided because aspirin can increase internal bleeding in the eye. People taking medication to keep their blood from clotting or aspirin for any reason should tell the doctor immediately. Rarely, recurring bleeding requires surgical drainage by an ophthalmologist.

However, PREVENTION IS BETTER THAN CURE!

Burn eye injuries

Exposure to strong heat or chemicals makes the eyelids close quickly in a reflex reaction to protect the eyes from burns. Thus, only the eyelids may be burned, although extreme heat can also burn the eye itself.

The severity of the injury, the amount of pain, and the appearance of the eyelids depend on the depth of the burn.

Chemical burns can occur when an irritating substance gets into the eye. Even mildly irritating substances can cause substantial pain and damage the eye. Because the pain is so great, there’s a tendency to keep the eyelids closed, thereby keeping the substance against the eye for a prolonged period.

Treatment

To treat burns on the eyelids, a health care practitioner washes the area with a sterile solution and then applies an antibiotic ointment or a strip of gauze saturated with petroleum jelly. The treated area is covered with sterile dressings.

A chemical burn of the eye is treated by immediately flooding the open eye with water for up to 5 minutes. This treatment must be started even before trained medical personnel arrive. Although a person may have difficulty keeping the injured eye open during this painful treatment, quick removal of the chemical is essential. Severe burns may need to be treated by an ophthalmologist (eye surgeon) to preserve vision and prevent major complications, such as damage to the iris, perforation of the eye, and deformities of the eyelids. However, even with the best treatment, severe chemical burns of the cornea can lead to scarring, perforation of the eye, and blindness.

It is thus vital to take extra care and wear protective equipment when working with exposed chemicals.

Diabetes Mellitus

Introduction

Diabetes Mellitus is a disease that occurs when the pancreas does not secrete enough insulin or the body is unable to process it properly.  Insulin is the hormone that regulates the level of sugar (glucose) in the blood.  Diabetes can affect children and adults.

How does diabetes affect the retina?

Patients with diabetes are more likely to develop eye problems such as cataracts and glaucoma, but the disease’s effect on the retina is the main threat to vision. Most patients develop diabetic changes in the retina after approximately 10 years. The effect of diabetes on the eye is called diabetic retinopathy.

Over time, diabetes affects the circulatory system of the retina. First, the arteries in the retina become weakened and leak, forming small, dot-like haemorrhages.  These leaking vessels often lead to swelling or oedema in the retina and decreased vision.

In the next stage circulation problems cause areas of the retina to become oxygen-deprived or ischaemic.   New, fragile, vessels develop as the circulatory system attempts to maintain adequate oxygen levels within the retina.  This is called neovascularisation. Unfortunately, these delicate vessels haemorrhage easily.  Blood may leak into the retina and vitreous, causing spots or floaters, along with decreased vision.

In the later phases of the disease, continued abnormal vessel growth and scar tissue may cause serious problems such as retinal detachment.

Signs and Symptoms

The effect of diabetic retinopathy on vision varies, depending on the stage of the disease.  Some common symptoms of diabeticretinopathy are listed below, however, diabetes may cause other eye symptoms.

  • Variable blurred vision (this is often linked to blood sugar level changes)
  • Floaters and flashes
  • Sudden loss of vision
  • Detection and Diagnosis

Diabetic patients require routine eye examinations so related eye problems can be detected and treated as early as possible. Most patients with diabetic retinopathy are referred to vitreo-retinal surgeons who specialise in treating this disease.

Treatment

Diabetic retinopathy is treated in many ways depending on the stage of the disease and the specific problem that requires attention.

The abnormal growth of tiny blood vessels and the associated complication of bleeding is one of the most common problems treated by vitreo-retinal surgeons.  Laser surgery called pan-retinal photocoagulation (PRP) is often the treatment of choice. PRP destroys oxygen-deprived retinal tissue outside of the patient’s central vision. While this creates blind spots in the peripheral vision, PRP prevents further growth of the fragile vessels and seals the leaking ones. The goal of the treatment is to stop the progression of the disease.

Vitrectomy is another surgery for diabetic patients who suffer a vitreous haemorrhage (bleeding in the gel-like substance that fills the centre of the eye). The surgeon may also gently cut strands of vitreous attached to the retina that create traction and could lead to retinal detachment or tears. Retinal tears are often sealed with laser surgery.  Retinal detachment requires surgical treatment to reattach the retina to the back of the eye. The prognosis for visual recovery is dependent on the severity of the detachment.

Prevention

Researchers have found that diabetic patients who are able to maintain appropriate blood sugar levels have fewer eye problems than those with poor control.  Diet and exercise are important in the overall health of those with diabetes.

Diabetics can also greatly reduce the possibilities of eye complications by scheduling routine examinations with an eye care practitioner.  Many problems can be treated with much greater success when caught early!

Common eye problems (sight threatening)

Cataracts

A cataract is a clouding of part of the eye called the lens. Vision becomes blurred or dim because light cannot pass through the clouded lens to the back of the eye.Cataracts can form at any age, but most often in older people. In younger people they can result from injury, certain drugs, long-standing inflammation or illnesses such as diabetes. They can be treated through surgery.

Glaucoma

Glaucoma is characterised by raised pressure inside the eye, which can damage the optic nerve, reducing the field of vision and the ability to see clearly. Early detection is vital, as lost vision cannot be regained, but treatment can prevent furthervision loss.

Hypertension

Hypertension or high blood pressure leads to many changes in the blood vessels of the body. These same changes in blood vessels affect the eyes in many ways. It can cause painless but severe loss of vision in the eye. Many of the ocular conditions caused by hypertension may not have any symptoms in the initial stages. Therefore it is important to have a periodic eye check-up to detect these.

Diabetes

Diabetes can affect the eye in a number of ways. These usually involve the fine network of blood vessels in the retina. Although vision may be good, changes can be taking place to the retina that need treatment. And because most sight loss in diabetes is preventable, early diagnosis is vital. Have an eye examination every year! Do not wait until the vision has deteriorated to have an eye test.

Macular Degeneration

At the centre of the retina is the macula, a small area about the size of a pinhead. This is the most specialised part of the retinaand it is vital as it enables you to see fine detail and read small print. Sometimes the delicate cells of the macula become damaged and stop working. We do not know why this is, although it tends to happen as people get older (~60+). This is called age-related macular degeneration (ARMD). As more people delay retirement and continue working, central vision loss due to ARMD must be borne in mind.

Common eye problems (non-sight threatening)

These are mostly conditions that cause unclear vision (blur), but will not harm the eye if not attended to immediately.

Shortsightedness (myopia)

Occurs when light is focused in front of the retina and causes distance vision to become blurred. Near vision, however, is usually clear.

Long-sightedness (hyperopia)

Occurs when the natural tendency is to focus light beyond the retina rather than on it, and the eye has to make a compensating effort to re-focus. With a younger person this may only be possible with effort and may, for example, cause headaches when reading. In an older person, as well as making reading very difficult, it may also cause distance vision to become blurred.

Astigmatism

Occurs when the front of the eye is egg shaped instead of being regularly curved like a ball. In this case both distance and near vision may be distorted or blurred.

Presbyopia (ageing eye)

As we get older, the lens of the eye thickens and slowly loses its flexibility leading to a gradual decline in our ability to focus on objects that are close up. This loss of focusing ability is called PRESBYOPIA. Click here for an in-depth discussion.

Amblyopia (Lazy Eye)

Amblyopia (lazy eye) is poor vision in an eye that did not develop normally during childhood, for various reasons such as a squint, high unequal refractive error, and stimulus deprivation (caused by cataract, glaucoma, patching or any other obstacle that blocks the vision in the eye). It usually affects one eye but may also involve both eyes and is generally caused by lack of use of one eye, when brain ‘favours’ one eye over the other. Amblyopia is treatable to a degree by means of therapy and / or surgery.

The above conditions may present by themselves or in combination in either or both eyes.

Colour vision

Overview

Colour vision deficiency may be a hereditary condition or caused by disease of the optic nerve or retina. Acquired (not from birth) colour vision problems only affect the eye with the disease and may become progressively worse over time. Patients with a colour vision defect caused by disease usually have trouble discriminating blues and yellows.

Inherited colour vision deficiency is most common, affects both eyes, and does not worsen over time. This type is found in about 8% of males and 0.4% of females. These colour problems are linked to the X chromosome and are almost always passed from a mother to her son.

Colour vision deficiency may be partial (affecting only some colours), or complete (affecting all colours). Complete colour vision deficiency is very rare. For this reason it is better to refer to colour vision deficiency. Those who are completely colour blind often have other serious eye problems as well.

Photoreceptors called cones allow us to appreciate colour. These are concentrated in the very centre of the retina and contain three photosensitive pigments: red, green and blue. Those with defective colour vision have a deficiency or absence in one or more of these pigments.

Signs and Symptoms

The symptoms of colour vision deficiency are dependent on several factors, such as whether the problem is congenital, acquired, partial, or complete.

  • Difficulty distinguishing reds and greens (most common)
    Colour-normal vs colour-deficient viewed apples (these are the same apples)
  • Difficulty distinguishing blues and greens (less common)

The symptoms of more serious inherited colour vision problems and some acquired types’ problems may include:

  • Objects appear as various shades of grey (complete colour blindness – very rare)
  • Reduced vision
  • Nystagmus (continuous small and jerky eye movements)

Detection and Diagnosis

Colour vision deficiency is most commonly detected with special coloured charts called the Ishihara Test Plates. On each plate is a number composed of coloured dots. Once the colour defect is identified, more detailed colour vision tests may be performed. Other colour vision tests exist, but the Ishihara is popular due to its sensitivity and ease of use.

Treatment

There is no treatment or cure for colour vision deficiency. Those with mild colour deficiencies learn to associate colours with certain objects and are usually able to identify colour as everyone else does. However, they are unable to appreciate colour in the same way as those with normal colour vision.

Cataracts

Cataracts are often encountered and misunderstood in everyday life.

A cataract is a cloudiness (opacity) in the eye’s lens that impairs vision.

It is often confused with a pterygium (pronounced tih-ree-jum) – a fleshy growth of the conjunctiva onto the cornea.

 

 

Cataracts produce a progressive, painless loss of vision. Their cause is often not known, although they sometimes result from exposure to x-rays (such as high-dose radiotherapy to the eye), prolonged and strong sunlight, inflammatory eye diseases, certain drugs (such as corticosteroids), or complications of other diseases such as diabetes. They are more common in older people (65+); babies can be born with cataracts (congenital cataracts).

Symptoms

Because all light entering the eye must pass through the lens, any part of the lens that blocks, distorts, or diffuses light can cause poor vision – similar to looking through a bathroom window. How much vision deteriorates depends on where in the lens the cataract is and how dense (mature) it is.

In bright light, the pupil constricts, narrowing the cone of light entering the eye, so that it cannot easily pass around a central cataract. Thus, bright lights can be especially disturbing to many people with cataracts, who see haloes around lights, glare, and scattering of light. Such problems are particularly troubling when a person moves from a dark to a brightly lit space or tries to read with a bright lamp.

Surprisingly, a cataract in the central part of the lens (nuclear cataract) may improve vision at first. The cataract refocuses light, improving vision for objects close to the eye – it renders the eye more myopic (shortsighted) or less hyperopic (farsighted). Older people, who generally have trouble seeing things that are close, may discover that they can read again without glasses, a phenomenon often described as gaining ‘second sight’. This is temporary, though.

Diagnosis and Treatment

A doctor can see a cataract while examining the eye with an ophthalmoscope (an instrument used to view the inside of the eye). Using an instrument called a slit lamp, a doctor can see the exact location of the cataract and the extent of its opacity.

The only way to treat a cataract is through surgical removal of the lens. People who have a cataract can determine when to have the surgery. When they feel unsafe, uncomfortable, or unable to perform daily tasks (usually visual acuity of 6/12 or worse), they may be ready for surgery. There is no great advantage to having surgery before then.

Before surgery, a person with a cataract can try other measures, such as spectacles and contact lenses which may possibly improve vision.

During the operation the lens is removed, and, most often, a new plastic or silicone lens is inserted; this artificial lens is called a lens implant. Without a lens implant, people usually need a contact lens. If they cannot wear a contact lens, they can try spectacles, which are very thick and tend to distort vision.

Cataract surgery is common and usually safe. To protect the eye from injury, the person wears glasses or a shield at night until healing is complete. The person visits the doctor the day after surgery and then typically every week or two for 6 weeks, after which a new spectacle prescription may be required.

Sometimes people develop an opacity behind a lens implant weeks or even years after it is implanted. Usually, such an opacity can be treated with a laser.