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MODULE 11 Part 2 COURSE CODE: C-7984 Optometric management of posterior segment – 30 anomalies CET

Omar Mahroo MA, MB, BChir, PhD Chris Hammond MB, BChir, MD, MRCP, FRCOphth 08/02/08

As the saying goes, the eyes are a window to the soul. They are also a window to the brain, and one can discover a number of conditions, sometimes life-threatening, affecting the brain by their effect on optic nerve appearance and function.

The main concerns when assessing any Generally if the answer is yes to which is defined as bilateral swollen abnormalities are (1) ‘Do I need to refer?’ some/all of the above, the more worried discs due to raised intracranial and (2) ‘If so, how urgently?’ In general, one is and the more likely that referral is pressure (e.g. due to an intracranial abnormalities that are of acute onset, warranted. tumour) and can hence indicate associated with symptoms or signs of potentially life-threatening disease. compromised optic nerve function, even Disc appearance Discs may also be swollen in a number when the nerve head looks normal, or Abnormal disc features are often not in of other states, but bilateral swollen, with pain, tend to be more urgent than themselves specific for one particular hyperaemic discs, perhaps with those that are long-standing, or pathology, except in the case of peripapillary haemorrhages and congenital, and asymptomatic. particular congenital malformations associated with a headache makes which will be mentioned later. Of papilloedema more likely. Other Important considerations course, the presence of a congenital causes of disc swelling include when suspecting optic nerve malformation does not exclude accelerated hypertension and disease acquired disease, and so one should be inflammation (papillitis) as well as A general history and ophthalmic wary in attributing any new symptoms acute anterior ischaemic optic examination, including checking of to a congenital anomaly. neuropathy, though in this case the intraocular pressures and full fundal Key pathological features to look out disc is pale, rather than hyperaemic. inspection is useful in assessing any for include the following: The may also look swollen ocular disease, including optic nerve • Swelling in a number of normal states – e.g. problems. • Hyperaemia , tilted discs, The following are important specific • Pallor peripapillary myelination and in the questions to bear in mind when assessing • New vessels crowded, small discs of any potential optic nerve abnormalities. • Absent venous pulsation hypermetropes. • Does the disc look abnormal? • Abnormal cupping The optic disc may also be swollen • Is it swollen? • Disc haemorrhages in central retinal vein occlusions, • Are symptoms of recent onset? posterior and in ocular • Are there specific patterns of pain? Swelling hypotony, hence a full fundal • Is there evidence of abnormal nerve Swollen discs (elevated, with indistinct examination and measurement of function? margins) may mean papilloedema, intraocular pressure is also important.

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Hyperaemia significant (unless it is clear that the movement, and will start to improve over Although a pink disc is healthy, absence of pulsation is new). the next few weeks, although brightness hyperaemic, swollen discs occur in perception may remain impaired for papillitis and papilloedema as above. Abnormal cupping several months. Gradually, slowly Abnormal cupping, where the progressive visual loss might suggest a Pallor neuroretinal rim containing the nerve compressive cause. Chronic, Disc pallor occurs in anterior ischaemic fibres leaving the eye is thinned, may be symmetrical, bilateral progressive or (AION). If the disc is indicative of . A cup-to-disc stable visual loss is seen in toxic or swollen as well, this may indicate that the ratio of 0.3 or less is normal. A higher nutritional optic neuropathies. In ischaemia is acute and hence referral is cup-disc ratio may also be normal – congenital anomalies, symptoms, if any, 31 more urgent, particularly as the cause termed physiological cupping – when tend to be stable, unless a complication may be giant cell arteritis (GCA) – a there is a normal number of nerve fibres arises, such as serous macular neuro-ophthalmic emergency. Specific leaving the eye, but the scleral canal detachment in individuals with optic disc CET patterns of pain are associated with GCA. through which they exit is large (e.g. in pits. Non-arteritic AION is less urgent, but myopic eyes), and so the cup-disc ratio is Leber’s hereditary optic neuropathy usually occurs only in the context of larger than normal. A difference in cup- usually manifests as visual loss over four 08/02/08 small, crowded discs. A pale, flat atrophic disc ratios between the two eyes of more to six weeks with about eight weeks’ disc indicates longstanding ischaemia than 0.2 is suspicious. delay between the first and second eye. It and so referral is less urgent. Pale, grey usually affects young men in their teens discs can also occur after chronic Haemorrhages having a family history of vision loss in papilloedema (e.g. idiopathic intracranial Disc haemorrhages may be seen in the males. hypertension) and papillitis. These context of papilloedema, diabetic conditions where the disc is atrophic and , central retinal vein Patterns of pain pale, but had been swollen previously, are occlusion, glaucoma and other Patients often present to optometrists known as secondary optic atrophy. conditions. with a headache, and it is important to A pale disc with crisp margins, i.e. distinguish relatively benign tension where there has been no prior swelling, Duration of symptoms headaches from more serious causes. The indicates primary optic atrophy, and this Optic nerve disease can often be headaches of raised intracranial pressure can occur in hereditary or toxic optic asymptomatic, and picked up only at tend to be worse in the morning on neuropathies and also following any routine optometric examination. This is waking or at night, as CSF pressure rises lesions affecting the optic nerve behind especially true of congenital anomalies, when lying flat. They may also be worse the eye, i.e. anywhere from the but also can be true of acquired on bending over or straining as these also retrolaminar portion up to the lateral conditions such as glaucoma and even cause rises in pressure, and may be geniculate body where the optic nerve papilloedema. associated with nausea and vomiting. fibres end. Hence, this can include past When symptoms are present, the more Tension headaches, however, are retrobulbar and recent the onset, the more urgent the intermittent, usually come on later in the compression due to tumours or problem might be. When symptoms of day, and are frequently described as a aneurysms. Lesions at the optic chiasm or visual loss are in one eye only, frontal or retro-orbital band of tightness. further back may cause areas of optic establishing their time-course may be Pain on eye movements is a frequent atrophy in both eyes. In addition, atrophy difficult. Long-standing symptoms, feature of optic neuritis. The intra-orbital can be diffuse or sectoral depending on especially the negative symptoms portion of the optic nerve sheath gives which nerve fibres are affected. A pale, characteristic of optic nerve disease, rise to part of the origin of the superior cupped disc occurs in advanced might only be noticed when the patient and inferior rectus muscles, and so is glaucoma. happens to rub or close the other eye. It stretched by eye movements. can be helpful to ask when vision was last Tenderness over the temporal artery, New vessels known to be normal in that eye, and thus scalp pain, e.g. on combing one’s hair, and New vessels at the disc are usually a sign establish an upper limit for the duration jaw claudication (pain in the jaws on of proliferative and of visual loss. chewing, relieved by rest) are features of will often be seen in the context of other Symptoms that are worsening or GCA (also known as temporal arteritis) diabetic retinopathy. This is an indication changing, e.g. transient visual and hence could indicate an emergency for urgent referral for treatment (laser obscurations are also more worrying than situation where urgent steroid treatment photocoagulation of the to stop the those that are static. is required to prevent vascular occlusion hypoxic drive). As vascular events tend to be rapid, and blindness. visual loss in anterior ischemic optic Absent venous pulsation neuropathy is normally sudden, although Evidence of abnormal disc Absent venous pulsation can indicate there are cases where it develops over a function raised intracranial pressure, but pulsation couple of weeks. In optic neuritis, visual Visual acuity and contrast sensitivity is also absent in 20% of normal loss usually develops over a number of Visual acuity should be measured, e.g. individuals, so on its own may not be days, often associated with pain on eye with a Snellen chart, with full refractive CONTINUING EDUCATION & CET Sponsored by: TRAINING  This issue CET: Free Worth 2 standard CET points To gain more standard CET points for this year’s PAYL series, enter online at: www.otcet.co.uk or ¥ 0207 878 2412

correction, or with a pinhole. It should be occur in retinal disease. However, there small) and Leber’s hereditary optic tested for near, e.g. with close reading are some optic nerve conditions in which neuropathy (when the is large). charts, as well as for distance. In the early blue dyshcromatopsia may occur Enlargement of the blind spot may occur stages of disease, the visual acuity may be including glaucoma, autosomal in papilleodema and congenital optic only slightly decreased. Contrast dominant optic atrophy, chronic nerve anomalies. sensitivity tests spatial resolution more papilloedema and even demyelinating Field defects that respect the thoroughly and can pick up more subtle optic neuropathy. horizontal meridian (i.e. they do not visual loss. cross it) occur in anterior ischaemic optic Reduced brightness perception neuropathy (inferior altitudinal), optic 32 Afferent pupillary defect This can also be tested by asking the nerve head drusen, papilloedema and This is an objective test. A relative patient to compare brightness perceived glaucoma. In advanced papilloedema or afferent pupillary defect (RAPD) is useful in each eye in turn, and may remain glaucoma, the whole field is constricted.

CET in detecting current or previous optic impaired even after visual acuity has Field defects due to optic nerve nerve disease, and in ruling out returned to normal, e.g. after an episode compression at or behind the chiasm functional or non-organic visual loss. It is of optic neuritis. tend to respect the vertical meridian and important to remember that it signifies an may progress. Tilted optic discs may give 08/02/08 asymmetry of conduction between the Visual field defects field defects that look as if they respect two optic nerves, so is only present in Optic nerve diseases cause negative the vertical meridian; usually, however, unilateral or asymmetric optic nerve visual symptoms, i.e. loss of an area of they do cross the midline somewhere disease – if, for example, there is bilateral vision, whilst macular diseases often give and, as they are congenital, they do not optic nerve disease, e.g. a pituitary positive symptoms (distortion of images, progress. tumour causing compression at the etc.). One can, however, experience Disorders affecting the chiasm or optic chiasm, then it may be absent. photopsia with optic nerve disease. tracts will give field defects in both eyes Intermittent transient obscurations of (bitemporal hemianopia in chiasmal Reduced colour vision vision may occur with papilloedema: compression, homonymous defects in Colour vision is reduced in optic nerve vision disappears for a second or two, more posterior lesions), whilst those disease, although it can also be impaired often when the intracranial pressure is affecting the nerve before the chiasm will in macular disease. However, in the raised such as bending down or give monocular defects only. presence of reasonably good visual coughing. Loss of vision associated with acuity, an acquired colour vision defect is gaze is characteristic of lesions that quite a good indicator of optic compress the orbital optic nerve, Main types of optic neuropathy. One can test this by simply classically optic nerve sheath asking the patient to look at a red object meningioma. nerve abnormality with each eye in turn and report whether The pattern of field loss may hint at the the ‘redness’ was the same. One can also cause. A central scotoma may be seen in Optic neuritis test colour vision more formally. neuropathies associated with Optic neuritis refers to an inflammatory Kollner’s rule holds that red-green demyelination (diffuse loss might be seen or demyelinating process affecting the dyschromatopsia occurs in optic nerve on a Humphrey visual field), toxic or optic nerve. disease whereas blue-yellow defects nutritional states (when the scotoma is Anatomically, it may be classified as retrobulbar neuritis (affecting the nerve Retrobulbar neuritis Optic nerve head is not involved, so the disc looks normal. behind the eye), papillitis (affecting the This is the most common type in adults; often represents disc) or neuroretinitis (affecting the disc demyelination. and the retinal nerve fibre layer also) – see Table 1. Papillitis Optic disc is inflamed, swollen and hyperaemic. Causes of optic neuritis include the There may be peripapillary flame-shaped haemorrhages. following: This is the most common type in children, often bilateral and • Demyelination (commonest in adults) post-viral. • Post-viral (commonest in children) • Adjacent Neuroretinitis Inflammation at the disc and also the retinal nerve fibre layer. • Granulomatous inflammation or A “macular star” develops as disc swelling resolves. autoimmune vascultides Less common than the other types; rarely represents demyelination. 25% of cases are idiopathic (Leber idiopathic stellate Demyelination neuroretinitis). Optic nerve fibres are myelinated from Other cases associated with cat-scratch fever (60%) or other the lamina cribrosa onwards, and conditions. demyelinating optic neuritis involves loss of this myelin sheath and deposition

Women are more commonly affected doubt, electrodiagnostic tests can be rubella and glandular fever, or even after than men, and presentation is usually helpful to check for delayed visual immunisation. Bilateral papillitis is between the ages of 20 and 40 years, often evoked potentials. In classic optic usually seen, and there may be other with pain on eye movements or a retro- neuritis, investigations are not always neurological features, from headaches to orbital headache which may resolve over needed. Although MRI can identify seizures. Treatment in most patients is a week or so, associated with progressive individuals at higher risk of MS, there is not required, as prognosis is good, but visual loss in the affected eye. Acuity no real preventative treatment and no intravenous steroids are considered in usually falls to between 6/18 and 6/60. way of predicting when the next attack severe visual loss. Some patients experience tiny white might occur or how mild or severe future Infectious optic neuritis can be sinus- flashes (phosphenes). A relative afferent disease might be. Thus discussing related, associated with severe headache 33 pupillary defect, loss of colour vision, possibilities of MS with patients is and spheno-ethmoidal sinusitis. and a centro-caecal scotoma, or diffuse probably not helpful unless patients Treatment is with systemic antibiotics depression of the central visual field, themselves ask or have had any other and sometimes surgical drainage. Other CET may be demonstrated. The disc usually neurological symptoms making MS very infectious causes include cat-scratch looks normal as the neuritis is usually likely. fever, , Lyme disease and retrobulbar. Much later there may be In terms of prognosis, 75% of patients Varicella zoster virus. In terms of non- 08/02/08 optic atrophy. If the patient has had recover to a visual acuity of 6/9 or better, infectious causes, optic neuritis may be previous optic neuritis in the other eye, although colour vision and brightness seen in some autoimmune vasculitides there may be some atrophy evident at the perception may remain abnormal. A and in – up to 5% of patients disc which will give a clue to the mild afferent pupillary defect may also with neurosarcoid may be affected, with diagnosis. persist. In total 10% of patients may the optic disc sometimes having a lumpy Optic neuritis may be an isolated develop chronic optic neuritis. appearance, suggestive of the episode in many cases. However, there is Treatment dose not influence eventual granulomatous inflammation a 38% risk of developing multiple visual outcome – this was shown by the characteristic of sarcoid. sclerosis (MS) (a disease characterised by Optic Neuritis Treatment Trial. episodes of demyelination of different Intravenous and oral steroids may speed Anterior ischaemic optic parts of the central nervous system up recovery, but have no effect on final neuropathy separated in time) over the next 10 years. outcome, and can give rise to side- Anterior ischaemic optic neuropathy The risk is 56% if T2-signal lesions are effects. Oral prednisolone alone has been (AION) is due to occlusion of the short seen on MRI (see Fig. 1), and 22% if no associated with a higher recurrence rate. posterior ciliary arteries which supply such lesions are seen. Other factors that Intramuscular interferon beta-1a has the optic nerve head. The cause can be increase the risk of developing MS are a been shown to produce a small benefit. non-arteritic, which is more common, or winter onset of optic neuritis, patients arteritic, which is more serious. who are genetically HLA-DR2 positive, Other causes of optic neuritis and those whose symptoms are worse Post-viral optic neuritis occurs, most Non-arteritic AION with elevation of body temperature (the commonly in children, one to three This is the most common optic Uhtoff phenomenon). weeks after such as measles, neuropathy in the elderly. Men are more If the diagnosis of optic neuritis is in mumps, chickenpox, whooping cough, commonly affected, and presentation is usually between 50 and 70 years, with sudden, painless visual loss; occasionally it may be progressive in a step-wise manner. The extent of acuity and colour vision impairment may vary. An altitudinal field defect is commonly seen, i.e. either the upper or lower field. Acutely, the optic disc is swollen and pale (Fig. 2a), especially the sector that is infarcted. The disc later becomes atrophic (Fig. 2b). An important risk factor is having a small, crowded, hypermetropic looking disc, with a very small cup, the so-called “disc at risk” (see Fig. 2a). Other risk factors include those for general cardiovascular disease, i.e. < Figure 1. MRI scan hypertension, diabetes, high cholesterol, Two slices of the MRI scan of a 23 year old patient with optic neuritis. The white lesions seen antiphospholipid syndrome, elevated are typical of those seen in the periventricular area in multiple sclerosis, and indicate a higher serum homocysteine levels, etc. and also risk of developing further neurological problems. sudden hypotensive events, CONTINUING EDUCATION & CET Sponsored by: TRAINING  This issue CET: Free Worth 2 standard CET points To gain more standard CET points for this year’s PAYL series, enter online at: www.otcet.co.uk or ¥ 0207 878 2412

34 CET < Figure 2a. Anterior ischaemic optic neuropathy < Figure 2b. Anterior ischaemic optic neuropathy Fig 2a shows the discs of a 48 year old man with AION affecting Fig 2b shows the same patient’s discs photographed 9 months his right eye, with a classic pale swollen disc, associated with a later: he has optic atrophy in the right disc, but has 08/02/08 nerve fibre layer haemorrhage, and the small “disc at risk” can unfortunately presented with loss of vision in his left eye, with also be noted in left eye. AION now affecting this eye.

surgery and even use of sildenafil commonly affected, and patients are inflammation. A temporal artery biopsy (Viagra). Thus, a general medical referral usually over 60. Systemic features of shows “giant cells” under microscopy. is sometimes indicated. GCA may be noted, including headache, Treatment is usually initiated A total of 6% of patients have scalp tenderness, malaise, fever, weight beforehand if the diagnosis is strongly recurrences in the same eye. In all 10% loss and jaw claudication, although in suspected, and consists of high dose oral will have involvement of the other eye 20% these features are absent at steroids, e.g. 80mg of prednisolone, in the next two years and 15% after five presentation (occult GCA). The subsequently reduced over time. years. There is no definitive treatment to condition is serious as, if untreated, improve vision or prevent deterioration, visual loss may rapidly become Papilloedema although aspirin may have a role, and bilateral, in up to 65% within three This refers to swollen optic discs due to general cardiovascular risk factors such weeks. Hence, if suspected, urgent raised intracranial pressure (ICP). It as diabetes and hypertension should be hospital referral is indicated. We would necessitates emergency referral if addressed. strongly recommend optometrists refer detected. Swollen discs due to other any patient with AION to hospital causes are not papilloedema, and discs Arteritic AION urgently, allowing ophthalmologists the that appear falsely swollen are termed Arteritic AION is associated with giant responsibility to decide whether the pseudopapilloedema. It is important to cell arteritis (GCA) and gives the same AION is artertic or non-arteritic, because note that visual function (acuity, colour disc appearance as non-arteritic AION. of the implications of untreated GCA. vision, visual field testing) is usually There may be associated nerve fibre Blood tests may aid the diagnosis: an normal in early papilloedema. However, layer haemorrhages or even choroidal elevated ESR – erythrocyte most patients have symptoms. infarcts, and the visual loss tends to be sedimentation rate – or CRP – C-reactive Presenting symptoms include the more severe. Women are more protein – show evidence of characteristic headache as described above. Note that children can also get Mechanical Elevation of the optic nerve head papilloedema, so it is worth attempting Blurring of disc margins to examine their discs also. Patients may Filling in of the physiological cup complain of transient visual Oedema of the peripapillary nerve fibre layer obscurations – loss of vision lasting Retinal and/or choroidal folds seconds, often with changes in posture Vintage papilloedema: disc pallor with white refractile bodies or straining, e.g. the Valsalva manoeuvre (forced breathing out against a closed Vascular Hyperaemia of the disc glottis). There might also be other signs Loss of spontaneous venous pulsation of raised ICP such as a , Venous dilation giving on lateral gaze: this is Obscuration of small surface vessels on disc the “pseudo-localising sign” (the nerve Peripapillary haemorrhages (flame-shaped) is stretched by the high ICP). Visual Exudates in or around the disc acuity is initially normal, but later falls. Nerve fibre layer infarcts (cotton wool spots) Visual field tests show an enlarged blind spot initially and progressive field < Table 2 constriction in late stages. Signs of papilloedema Chronologically papilloedema has CONTINUING CET EDUCATION & TRAINING Worth 2 standard This issue CET: Free  CET points To gain more standard CET points for this year’s PAYL series, enter online at: www.otcet.co.uk or ¥ 0207 878 2412

been divided into early, acute, chronic and vintage stages (see Fig. 3), with Are there symptoms of raised ICP? gradually increasing severity of Typical headache symptoms and signs. Early signs include Transient visual obscurations blurring of the disc margins (initially Diplopia on lateral gaze (VI nerve palsy) nasal, then superior, inferior and temporal), disc hyperaemia and loss of What is the refraction of the eye? spontaneous venous pulsation. Venous Disc may look swollen in: pulsations can be detected using the – hypermetropes high magnification of a direct – myopes with tilted discs 35 ophthalmoscope and observing a vein just as it leaves the disc margin. If Is there spontaneous venous pulsations are present, raised ICP is very pulsation? CET unlikely. If absent, this does not Presence makes papilloedema unlikely necessarily mean papilloedema as < Figure 4. Pseudopapilloedema pulsations are absent in a fifth of normal Is there anomalous retinal

Figure 4a shows buried disc drusen. The disc 08/02/08 people. Table 2 lists fundus signs of looks swollen, but note the irregular “lumpy” vasculature? papilloedema. edge to the disc, the anomalous retinal vessels Can be associated with disc drusen Causes of pseudopapilloedema and the yellowish appearance. include hypermetropic discs, which are Are there vascular signs of small, crowded, with a small cup, and papillodema? hence may appear swollen, or myopic Peripapillary haemorrhages tilted discs, which may appear swollen Exudates or retinal cotton wool spots superonasally (see Fig. 4). Other causes (See Table 2) include peripapillary nerve fibre myelination (which may also give the < Table 3. appearance of exudates) and buried Questions when faced with swollen discs optic disc drusen. Table 3 summarises suspicious of papilloedema the important questions to ask when papilloedema. identify the cause, and sometimes a Visual field testing may be useful in Fig 4b illustrates tilted small discs, which are lumbar puncture is required to measure showing an enlarged blind spot, or, in sometimes confused for swollen discs, the pressure and to examine the later stages, constriction of the field. especially the temporal edge. cerebrospinal fluid (CSF). Fluorescein angiography can be helpful Idiopathic intracranial hypertension in confirming the diagnosis – the early hydrocephalus (raised ICP due to refers to raised ICP of unknown cause, angiogram shows a dilated capillary blockage of flow of cerebrospinal fluid), i.e. not due to a mass lesion, and if network over the disc and the late venous sinus thrombosis, meningitis untreated can lead to blindness. angiogram shows leakage from the disc and idiopathic intracranial Typically it affects obese, young women (Fig. 5). hypertension. CT (computerised with no other neurological symptoms, Causes of papilloedema include tomography) or MRI (magnetic often with recent weight gain. The most intracranial masses (brain tumours), resonance imaging) brain scans can help serious complication is optic atrophy

< Figure 3. Papilloedema Fig 3b shows established papilloedema with Fig 3c shows vintage papilloedema in the These three sets of optic disc photographs elevated nerve head and loss of the optic right disc with some refractile white crystals show early, established and chronic disc cup. on the surface, and the left disc is already papilloedema. Fig 3a shows blurring of the atrophic due to chronic papilloedema – this nasal optic disc margin and a hyperaemic eye has already lost significant vision in a 24 disc, and it would be important to look for year old patient with idiopathic intracranial lack of spontaneous venous pulsation to hypertension. confirm the suspicious appearance. CONTINUING EDUCATION & CET Sponsored by: TRAINING  This issue CET: Free Worth 2 standard CET points To gain more standard CET points for this year’s PAYL series, enter online at: www.otcet.co.uk or ¥ 0207 878 2412

< Figure 5. neurofibromatosis Type 1, an autosomal Fluorescein dominant inherited disease that angiogram of an involves benign nerve tumours in optic disc in a different nerves throughout the body. patient with Patients with an optic nerve sheath papilloedema meningioma are usually adults, Fig 5a is the early typically middle-aged women, arterial phase of the presenting with the classic triad of dye transit and shows dilated visual loss, optic atrophy and 36 capillaries over the optociliary shunt vessels (on the disc surface of the optic between the posterior ciliary and retinal disc. The arteries circulations) – see Fig. 6c. They often

CET are filled with dye have a proptosis if the meningioma is (white) and the < Figure 6. Compressive optic intraorbital. Surgery is difficult as the veins still empty neuropathies tumour can rarely be removed, but the (black). Fig 5b Figure 6a shows the CT scan of a child with tumours may respond to radiotherapy, 08/02/08 shows the late photograph of this a swelling of the optic nerve which is an and some are hormone-dependent, disc with fluorescein optic nerve glioma. responding to anti-hormonal treatment. leakage from the optic disc. Diabetic papillopathy This is a rare condition affecting diabetics, usually Type 1 diabetics with constriction of peripheral fields. It around their twenties. It involves mild can be associated with steroid disc swelling, which is bilateral in use/withdrawal and with tetracyclines around 75% of cases, and which may be and vitamin A. Treatment includes associated with mild visual loss – acuity encouragement of weight loss, which is rarely worse than 6/12. It usually may be curative. Acetazolamide reduces resolves spontaneously, but may take CSF production and can be helpful. several months. The aetiology is unclear However, if there is evidence of but it may represent a mild ischaemic progressive field constriction, surgical optic neuropathy. Clearly other causes procedures may be required, which of disc swelling should be excluded first include shunting, where the CSF is before attributing it to the diabetes. diverted to the abdominal peritoneal cavity, or optic nerve sheath Toxic or nutritional optic fenestration, where the optic nerve neuropathy sheath is incised behind the eye to allow Figure 6b is the CT scan of a patient with an This condition is sometimes called CSF to leak. optic nerve sheath meningioma which can be “tobacco-alcohol” as it seen on the different cuts as the tortuous frequently presents in individuals, who Compressive optic thickened and calcified nerve sheath of the are smokers and heavy drinkers. In neuropathy right optic nerve (seen above). nutritional optic neuropathy, there is The optic nerve glioma (Fig. 6a) and usually a deficiency of B vitamins – B1 optic nerve sheath meningioma (Fig. 6b) (thiamine) or B12 (seen in bowel are the two main tumours that cause absorption problems). Treatment is with visual loss by compressing the optic vitamin replacement. nerve (as opposed to those which Presentation is with fairly sudden, compress the optic chiasm, such as progressive loss of vision, and a cento- pituitary tumours, resulting in the caecal scotoma, fairly symmetrical in characteristic bitemporal hemianopia). both eyes, with impaired colour vision. Pathologies that compress the nerve in The visual field defect may be difficult the , such as thyroid eye disease, to define using a white target, but tends may also cause proptosis. to be larger and easier to plot with a red In total 75% of optic nerve gliomas target. Optic discs may be normal present with visual loss in the first initially, or show subtle temporal pallor, decade of life, and 90% by the age of 20. The optic discs of this patient are seen in with splinter-shaped haemorrhage and The course of the disease is usually figure 6c; the left disc is normal but the right sometimes minimal disc oedema. In the benign, and surgery is not performed as disc displays the classic triad of signs of early stages, the visual loss is reversible, it involves severing the optic nerve. optic atrophy, disc swelling and optociliary but later advanced stages are often Gliomas can be associated with shunt vessels. unresponsive to treatment. CONTINUING CET EDUCATION & TRAINING Worth 2 standard This issue CET: Free  CET points To gain more standard CET points for this year’s PAYL series, enter online at: www.otcet.co.uk or ¥ 0207 878 2412

Leber’s hereditary optic neuropathy Anomaly Features, significant associations or complications This is a rare cause of bilateral optic neuropathy, usually presenting in Tilted disc • Nerve enters eye obliquely. Disc usually directed inferonasally. Elevated males, who are affected nine times side may have indistinct margin. Temporal vessels may deviate nasally more commonly than females, initially (situs inversus). between the ages of 10 and 35, with a • May have superotemporal field defects that do not respect the midline peak incidence in the teens. It results • Associations: myopic astigmatic , chorioretinal thinning from mitochondrial mutations, thus inheritance is always through the Optic disc pit • Large disc with pit, usually temporal. Field defects common. 37 mother. Atypical cases may affect • 45% of non-central pits will develop serous macular detachment (25% females and present at other ages, so it resolve; some might need laser or vitrectomy). should be considered in any patient CET with bilateral optic neuropathy. There Optic disc • Due to incomplete closure of optic fissure during development. is typically painless loss of vision in coloboma Excavation inferiorly (reduced fluorescence on fluorescein angiography) one eye over a few weeks, followed by • Acuity often reduced. Superior field defect. Complications include serous 08/02/08 similar loss in the other eye (usually macular detachment. after an eight-week delay). The disc • Associations: /fundus colobomas, microphthalmos, chromosomal looks hyperaemic, with indistinct abnormalities and systemic syndromes (e.g. CHARGE syndrome). margins – this is pseudo-oedema, as there is no leak on fluorescein Morning glory • Very rare, usually unilateral and sporadic. Ring of chorioretinal angiography. Dilated capillaries also anomaly disturbance around a large disc with a funnel-shaped excavation. White may be seen on the disc surface and tuft of glial tissue over centre. adjacent retina, and this telangiectatic • Increased number of vessels, emerging like spokes from rim of disc. microangiopathy may be seen in the • Visual acuity may be normal. Serous in 30%. fundi of asymptomatic female • Choroidal neovascularisation may develop. relatives. Visual loss is variable, with • Associations: frontonasal dysplasia, neurofibromatosis type 2 and some mutations having a worse PHACE syndrome. prognosis. Treatment is generally ineffective. Optic nerve • Small grey disc with surrounding halo of hypopigmentation (double ring hypoplasia sign). Reduced number of nerve fibres. Distance from fovea to temporal Other hereditary optic atrophies disc border is 3x disc diameter or more. There are other hereditary optic • Vision variable from blindness to normal acuity. If unilateral, may present atrophies that are rarer still. These with squint. include dominant optic atrophy (Kjer • Associated with a range of midline brain defects. Predispositions: syndrome: autosomal dominant maternal use of alcohol, LSD, quinine, steroids or other agents during inheritance, presenting typically gestation. before the age of 20), Behr syndrome (autosomal recessive inheritance, Prepapillary loop • Unilateral vessel loop from disc into vitreous. presenting in the first decade, • 10% develop obstruction of the retinal artery supplying the loop associated with abnormal gait and mental problems) and Wolfram Bergmeister papilla • Glial tissue on the disc surface (unilateral) syndrome (autosomal recessive inheritance, presenting by the age of Megalopapilla • Horizontal and vertical diameters are 2.1 mm or more 21, associated with diabetes mellitus, diabetes insipidus, deafness, mental Peripapillary • Normal disc at the bottom of a deep excavation. Acuity reduced. problems and other abnormalities). staphyloma • Complications: local retinal detachment

Congenital anomalies Optic nerve aplasia • Very rare: absent or rudimentary disc. Congenital anomalies of the optic disc are common. They are frequently Papillorenal • Autosomal dominant condition, central excavation in disc, central retinal insignificant, but can give rise to syndrome vessels replaced by cilioretinal vessels. Kidney abnormalities. visual field defects, be associated with other neurological defects or give rise Myelinated retinal • Ganglion cell axons are normally not myelinated until they pass out of the to macular problems. Some may be nerve fibres eye through the lamina cribrosa. Abnormal myelination in the retina or near the confused with papilloedema, disc can be mistaken for exudates or disc swelling (if at the disc margin). particularly optic disc drusen, the Optic disc dysplasia • A deformed disc that doesn’t conform to any recognised category. small discs of hypermetropes and tilted discs. CONTINUING EDUCATION & CET Sponsored by: TRAINING  This issue CET: Free Worth 2 standard CET points To gain more standard CET points for this year’s PAYL series, enter online at: www.otcet.co.uk or ¥ 0207 878 2412

Disc drusen Conclusions This refers to hyaline-like calcific Optic nerve abnormalities range from material within the optic nerve head, incidental congenital anomalies to affecting 0.3-1% of the population. The manifestations of sight-threatening condition is bilateral in approximately conditions such as temporal arteritis or 75% of cases, and may have autosomal even life-threatening disease, such as a dominant inheritance. Buried drusen brain tumour. A careful, systematic can be confused with disc swelling, as approach, examining optic disc they can give an irregular disc margin appearance, assessing patterns and 38 with an absent cup. Patients are usually chronology of symptoms, and looking for asymptomatic. Once they have evidence of optic nerve dysfunction, will appeared on the surface as whitish help one arrive at a differential diagnosis

CET lumps, which may happen during the and hence decide on appropriate teens, they are less easily confused with management. papilloedema. In addition, they are more likely to have anomalous vasculature, Further reading 08/02/08 such as trifurcation of first order retinal Riordan-Eva P. Clinical assessment of vessels, and the disc is more optic nerve disorders. Eye 2004; 18, pink/yellow, rather than truly 1161-1168 hyperaemic. Taylor D. Developmental Disc drusen can be associated with < Figure 7. Congenital disc abnormalities of the optic nerve and pigmentosa, angioid streaks and anomalies chiasm. Eye 2007; 21, 1271-1284 Alagille syndrome (a genetic condition Figure 7a is an example of an optic disc pit Kanski JJ Clinical : A with pale fundi, hypertelorism, biliary, (a small pit on the temporal edge of the disc) systematic approach. 6th ed. London: vertebral and heart problems). which may result in visual loss due to serous Elsevier; 2007. pp. 82-89, 786-802 Complications are rare, but fluid leaking underneath the macula. Figure include juxtapapillary choroidal neo- 7b displays myelinated nerve fibres, About the authors commonly misdiagnosed as exudates. vascularisation, disc new vessels, central Omar Mahroo MA, MB, BChir, PhD retinal arterial/venous occlusion and Trainee in Ophthalmology at the West limited field loss in 75%. detachment, colobomas due to Kent Eye Centre, Princess Royal incomplete closure of the optic fissure University Hospital, Bromley Other anomalies during development and myelinated Chris Hammond MB, BChir, MD, Tilted discs and small, hypermetropic nerve fibres (Fig. 7b), which can be MRCP, FRCOphth. Consultant discs have been mentioned. Other confused with a swollen disc (if at the Ophthalmologist and Clinical Director, anomalies include optic disc pits (Fig. margin) or exudates. Table 4 summarises West Kent Eye Centre, Princess Royal 7a), which can lead to serous macular some of these anomalies. University Hospital, Bromley

CET to a Masters - OT and City University join forces to provide CET that suits you

CITY UNIVERSITY and OT have joined forces allowing readers to Readers wishing to work towards a postgraduate qualification may achieve CET points through to a full Masters in Clinical Optometry. obtain 10 postgraduate credits by sitting a three hour examination As part of this scheme, OT is running a series of CET articles on relating to the OT CET articles. This examination is running on topics of direct relevance to optometrists. May 28 and is based on all the City CET articles (‘Paediatric Optometry’ and ‘Optometric Management of Anterior Segment Eye This is the second article of the new 2008 series – ‘Optometric Disease’) published in 2007. Those attending the three day Management of Posterior Segment Eye Disease’. Successfully modules at City may also take an examination to obtain a further complete the MCQs accompanying the current article and receive 2 15 postgraduate credits. CET points. Want to know more about the topic? The ‘Optometric Management of Posterior Segment Eye Disease’ MSc module is Other MSc modules running include: ‘Vision in the Aged’ - running July 13-15 2008. Participants may opt to complete just February 10-12. Alternatively, start your ‘Additional Supply/ the practical sessions or lectures or attend the full three days – the Supplementary Prescribing’ training with the ‘Principles of ‘Optometric Management of Posterior Segment Eye Disease’ CET Therapeutics’ distance learn ng module and follow it with the day is being held on July 13 at City University consisting of cutting ‘Principles of Prescribing’ running April 20-22. edge presentations by leading experts in the field. Extend your participation for a further two days (July 14-15) to obtain in-depth For further information see www.city.ac.uk/optometry/msc. knowledge and hands-on experience. Readers are advised to Contact Dr Michelle L Hennelly by emailing book early to avoid disappointment – the CET days will be ([email protected]) or call 020 7040 8352. heavily subscribed. CONTINUING EDUCATION & CET Sponsored by: TRAINING  This issue CET: Free Worth 2 standard CET points To gain more standard CET points for this year’s PAYL series, enter online at: www.otcet.co.uk or ¥ 0207 878 2412

Module questions Course code: c-7984 Please note, there is only one correct answer. Enter online or by form provided

An answer return form is included in this issue. It should be completed and returned to CET initiatives (c-7984) OT, Ten Alps plc, 9 Savoy Street, London WC2E 7HR by March 5 2008.

1. Which one of the following is correct? Causes of optic atrophy include: 7. Which one of the following does NOT cause papilloedema in adults? A vitamin C deficiency A idiopathic intracranial hypertension B an optic disc pit B optic neuritis C idiopathic intracranial hypertension C a brain tumour D postural hypotension D venous sinus thrombosis 39 2. Symptoms of raised intracranial pressure are most likely to include all the following except: 8. Which one of the following is correct? Idiopathic intracranial hypertension: A obscurations A always results in optic atrophy CET B nausea and vomiting B is caused by venous sinus thrombosis C diplopia C may cause peripheral visual field constriction D madarosis D usually affects young men

3. Which one of the following is correct? Adult patients with retrobulbar optic 9. Which one of the following is correct? Optic nerve sheath meningioma: 08/02/08 neuritis usually have: A peaks in incidence in the second decade of life A peripheral field constriction B may cause proptosis B pain on eye movements/headache C rarely causes visual loss C bilateral swollen optic discs D is associated with neurofibromatosis Type 1 D bilateral severe visual loss 10. Which one of the following is correct regarding diabetic papillopathy? 4. Which one of the following is correct? Non-arteritic anterior ischaemic A it is common optic neuropathy: B it generally affects people with Type II diabetes A produces an homonymous visual field defect C bilateral swelling of the optic disc occurs in around 75% of cases B occurs in large myopic “discs at risk” D patients will generally complain of extensive visual loss C may affect the second eye after the first eye D is associated with an elevated erythocyte sedimentation 11. Which one of the following regarding Leber’s hereditary optic neuropathy is incorrect? 5. Patients with early papilloedema are most likely to present with which one of A it affects males more than females the following? B the peak incidence of the condition occurs in the teens A a central scotoma C at the initial stages, patients suffer a bilateral loss of vision B headaches D inheritance is through the maternal side C a relative afferent pupillary defect D severe loss of vision 12. Which one of the following is correct? Optic disc drusen are usually: A unilateral 6. Which one of the following is correct? Clinical signs of early B symptomatic papilloedema include: C associated with anomalous vasculature A optociliary shunt vessels D caused by myelinated nerve fibres B retinal and choroidal folds C loss of spontaneous pulsation D venous sheathing

Please complete on-line by midnight on March 5 2008 - You will be unable to submit exams after this date – answers to the module will be published in our March 7 issue