Ocular Myasthenia. a guide. myaware.org 1

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1 Ocular Myasthenia a guide myaware.org 1

2 Contents 1. What is myasthenia? Myaware What is ocular myasthenia? Symptoms of ocular MG Extraocular muscles How do they diagnose ocular MG? Who s who? Treatments for ocular MG Why are the ocular muscles so vulnerable? Case Studies Glossary myaware.org

3 What is Myasthenia? Myasthenia means muscle weakness. This is confined to the voluntary muscles and does not affect either the autonomic system or sensation. It is characteristically fatigable and the harder the patients try, the weaker they get. So they are often strongest in the mornings and get weaker during the day. Whilst the Myasthenia can affect any muscles, they typically show a top down pattern particularly affecting movements of the eyes, face and voice. More seriously they can also affect swallowing and breathing, and so can be life-threatening. Myasthenia often gets worse with inter-current illnesses, fatigue or stress but it can also relapse or remit out of the blue. myaware.org 3

4 Myaware Myaware has been around for nearly 40 years and aims to make life easier for people living with myasthenia. They are working hard to raise awareness of myasthenia, as it is a little known condition. They provide support for people with myasthenia and their families, whilst offering practical advice and tips for living with the condition. Myaware also funds the research that brings us closer to finding a cure. They also raise money for specialist nurses and advisors. For a full list of upcoming fundraising and social events visit or 4 myaware.org

5 What is Ocular Myasthenia? Ocular myasthenia (MG) is a form of myasthenia gravis in which the extra ocular muscles, the muscles that control the eyes and eyelids, are easily fatigued and weakened. Symptoms of Ocular MG If you have ocular MG you are likely to have experienced double vision (diplopia) or drooping eyelids (ptosis). Your eyes will not move together in balanced alignment, causing you to see double images. One or both of your eyelids may also droop to cover all or part of the eye pupil, thus obstructing vision. Eye weakness will often change from day to day and during the day. Problems with eyes are often worse at the end of the day or after the eyes have been used for a prolonged period of time. You may find that your eye problems are temporarily improved if you rest your eyes by closing them for several minutes, when your symptoms are troubling you. If you have ocular MG, you will NOT have difficulty swallowing, speaking or breathing, nor will you experience any weakness of your arms and legs. myaware.org 5

6 What goes wrong with Myasthenia? The extraocular muscles are the six muscles that control the movements of the eyes. For reasons we don t fully understand, these muscles can be particularly affected by myasthenia. Usually our eye movements are synchronised but when these muscles become fatigued sometimes they don t move in accord with each other leading to double vision. Details of these muscles are shown below. Medial Rectus (MR) This moves the eye inwards, towards the nose (adduction) Lateral Rectus (LR) Moves the eye outwards, away from the nose (abduction) Superior Rectus (SR) Firstly moves the eye upwards (elevation) Secondly rotates the top of the eye towards the nose (intorsion) Thirdly moves the eye inward (adduction) Inferior Rectus (IR) Firstly moves the eye downwards (depression) Secondly rotates the top of the eye away from the nose (extorsion) Thirdly moves the eye inward (adduction) Superior Oblique (SO) Firstly rotates the top of the eye towards the nose (intorsion) Secondly moves the eye downwards (depression) Thirdly moves the eye upwards (abduction) 6 myaware.org

are also small muscles that control the eye lids, when they become fatigued drooping eye

7 Inferior Oblique (IR) Firstly rotates the top of the eye away from the nose (extorsion) Secondly moves the eye upwards (elevation) Thirdly moves the eye outwards (abduction) There are also small muscles that control the eye lids, when they become fatigued drooping eye lids (for which the medical name is ptosis) can occur. Extraocular muscle movements myaware.org 7

8 How is ocular MG diagnosed? Ocular MG is diagnosed in the same way as other myasthenias. If your symptoms only affect the muscles around your eyes for longer than two years then your condition is unlikely to progress to other muscles. Many people with ocular MG first consult an optician about their eye problem. Optometrists are frequently the first medical professionals to suspect MG and will refer you to a neurologist for further tests. You will have a blood test to detect the anti-acetylcholine receptor (AChR) antibodies, which are positive in around 50% of people with ocular myasthenia. If the test comes back negative, you may receive a very sensitive electrical test (Electromyography) on your facial muscles. In some cases, people will be given an injection to test out the body s response to a drug called Tensilon. 8 myaware.org

9 Who s who? Optometrist Optometrists are important allies for the myasthenia community. They are trained to examine the eyes to detect defects in vision, signs of injury, ocular diseases or abnormality and problems with general health and are often the first to suspect myasthenia. They often work in High Street opticians practices. Optician An ophthalmic optician is qualified to prescribe and dispense classes and contact lenses and to detect eye diseases. A dispensing optician is qualified to make and supply glasses and contact lenses. They often work in High Street opticians practices. Neurologist A neurologist is a doctor who specialises in disorders that affect the brain, spinal cord, nerves and muscles. Ophthalmologist These are specialists in medical and surgical eye problems. They perform operations on eyes. myaware.org 9

10 Treatments for ocular MG Ptosis Props These are useful if drug treatments are not fully successful. Before they are prescribed to you, it would be helpful for you to be shown samples of the different types of prop available. Ptosis props are designed to literally prop your eye open. Lundie Loops You may be offered a device called the Lundie Loop, which is a circle of stainless steel wire. They are designed so you can look through the middle of the loop. The upper part of the loop, which bears lightly on the eyelid, is fitness with a short piece of silicone rubber tubing. They are fitted exclusively by Mr J B Lundie,,. jblundie@talktalk.net Traditional bar ptosis props These can be fitted to most glasses. The length and size of them will be determined by the optometrist. Rubber tubing can also be used to cushion the bar. 10 myaware.org

11 Eye Prisms A prism is a wedge-shaped piece of glass or plastic that bends the light that shines through it. Fresnel prisms can be attached to your glasses and are an effective way of treating double vision. Fresnel prisms are thin, see through sheets of plastic. One side sticks to the lens of your glasses and the other side has special grooves in it that change the way the light enters your eye. You may need to wear prisms for several months. The strength can be adjusted to suit your eyes. If the Fresnel prisms are successful, you can have glasses made with prisms built in. Contact lens ptosis props These are used by some patients with myasthenia. Further information can be obtained from Ken Pullum, Principal Optometrist, Scleral Lens Service at Moorfield s Eye Hospital. Eye patch Wearing an eye patch will help you to see one image. When treating children, if you keep one eye consistently patched, vision in that eye will decrease so it is vital that you alternate the patch form one eye to the other to avoid permanent vision loss. Pyridostigmine As with most forms of myasthenia, pyridostigmine is usually the first-line treatment. For many people, pyridostigmine alone is able to control their symptoms. Side affects may include stomach cramps, digestive problems and an urgent need to urinate. To find out more visit Immunosuppressive drugs If pyridostigmine alone is not enough, immunosuppressive drugs may be introduced. The steroid prednisolone is often used. Dosage may have to be built up high before a lower maintenance level is found. Benefits of the drug will typically kick in after 2-3 months. Side effects may include weight gain, hypertension, glaucoma, cataract and/or osteoporosis. myaware.org 11

12 Why are the ocular muscles so vulnerable? The most important difference between the eye and eyelid muscles compared with other muscles of the body is that the eye muscles respond differently to immune attack. The eyes and the eyelid muscles are structurally different to the muscles in the body and limbs. They have fewer acetylcholine (ACh) receptors, which is where the defect occurs in autoimmune myasthenia. Also, eye muscles contract much more rapidly than other muscles and may be more likely to fatigue. The greater sensitivity of ocular muscles partly reflects subtle differences in your nerve muscle junctions. The eye muscles usually get less rest, need finer tuning and are less bulky than those in the legs. 12 myaware.org

13 Case Studies Charlotte, 5, developed a squint in her eyes and often closed one of her eyes when she was became tired. Charlotte went along to her GP with her parents and he suggested she had intermittent exotropia, also referred to as a divergent squint. When Charlotte visited the optician, her mother mentioned that she had droopy eyelids to him, who then confirmed a partial ptosis (upper eyelid drooping). Charlotte was then referred to a paediatric neurologist who diagnosed her with myasthenia. Charlotte s parents found the myaware kids Facebook group and with the help of the group, Charlotte has been able to meet other members who have myasthenia. Her parents notified her school about myasthenia and the school have put special measures in place to help Charlotte. A Whilst driving home from work, Ben, 23, noticed that he had intermittent blurred vision. Ben also found that he had to shut one of his eyes and turn his head to the left to see clearly. He went to see his doctor who referred him to see an optometrist, a person who gives advice on eye problems. His optometrist said that although he had normal vision in both eyes, he noticed a defect of the right abduction. After further testing, it was confirmed that Ben had myasthenia. After his diagnosis, Ben contacted myaware who reassured him and told him about the myaware support group on Facebook. Since joining the group, Ben has received support from other members and is looking forward to going back to work. myaware.org 13

14 Glossary Acetylcholine Receptors (AChR) are a tailor-made for the ACh to latch into on the nearby muscle surface. That then opens up channels into the muscles, allowing salt (sodium and calcium ions) to enter and trigger the muscle into action. Autoimmune relates to diseases cause by antibodies produced against substances naturally present in the body. Diplopia is double or blurred vision, especially when looking to the sides or up and down. EMG = Electromyography is where nerves are stimulated electrically and the resulting (electrical) impulses are measured in the muscles they supply. EMG helps Neurologists to sort out different congenital myasthenias and immune MG. Extraocular muscles are the six muscles that control the movement of the eye. Mestinon is the trade name for Pyridostigmine, a long-lasting anticholinesterase. Myasthenia is any form of muscle weakness, especially if caused by faults in the nerve. Ocular MG is MG affecting only the eyelids and/or eye movements and not other muscles. Ptosis is a drooping or falling of the upper or lower eyelid Pyridostigmine is a long-acting anti ACh esterase drug that blocks breakdown of spare ACh (also called Mestinon ). Tensilon (Edrophonium) is a short-acting anti AChE drug; for diagnosing myasthenia. It is injected into a vein and any resulting increase in muscle strength is measured. 14 myaware.org

15 Myaware Myaware is the only charity in the UK and Republic of Ireland dedicated solely to the care and support of patients with the myasthenias and to promoting education, awareness and research into these rare diseases. It helps to support all medical services involved in the treatment and care of people with myasthenia and particularly Neuromuscular Centres where there is particular expertise in all these conditions, whether autoimmune or congenital, ocular or generalised. A full range of information about the various myasthenias and support services for patients is available from Myaware. If you d like to help there are plenty of ways to get involved visit our website to find out more There you can also find out more about how you can donate to myaware. facebook.com/myastheniauk facebook.com/myawareie twitter.com/myawareuk twitter.com/myawareie myaware.org 15

16 MGA is a Registered Charity No. England & Wales Scotland SC Ireland CRA No Company Limited by Guarantee No (England). Myaware (Myasthenia Gravis Association), The College Business Centre, Uttoxeter New Road, Derby DE22 3WZ Tel: web: info@myaware.org

Myasthenia gravis. Page 1 of 7

Myasthenia gravis. Page 1 of 7 Myasthenia gravis What is myasthenia gravis? Myasthenia gravis (sometimes abbreviated to MG) is a chronic, autoimmune condition that causes muscle weakness and excessive muscle fatigue. It is rare, affecting