A common reason for referral to secondary eye-care services are retinal haemorrhages found on routine examination. Optometrists often refer such patients urgently to the medical retina clinic or their local eye casualty. However, a closer look at the retinal picture may enable better understanding of the likely aetiology. This would allow for the correct investigations to be requested and the promptness of referral to be considered more diligently.
Before we tackle some cases it is important that we re-visit some basic anatomy and ensure that we are using the correct terminology.
Blood supply to the Retina
The retina is highly metabolic and its blood supply reflects this. The inner 2/3 of the retina is supplied by branches from the central retinal artery and the outer 1/3 is supplied by the choroidal circulation.
The central retinal artery divides into superior and inferior branches which each divide into nasal and temporal branches. Functionally these are end-arteries. This means that there is insufficient collateral circulation to supply retinal tissue should these arteries become occluded. The temporal arcades approximate the macula. Within this area the central foveal avascular zone contains outer retinal layers only. The blood supply to this area is derived from the underlying choroidal circulation.
The post arteriole retinal capillaries can be found in the nerve fibre layer, whereas the pre-venular capillaries are found a little deeper - in the inner nuclear layer. These two plexuses allow communication between them.
Retinal haemorrhages - morphological categories
Subhyaloid / Pre-retinal haemorrhage
Subhyaloid haemorrhages are found between the inner limiting membrane and the posterior hyaloid face. A pre-retinal haemorrhage is located between the inner limiting membrane and nerve fibre layer.1 Both bleeds mask the underlying vessels. It is very difficult to differentiate between the two. Other terms you may come across are D-shaped or boat shaped haemorrhages. Although there are several terms for such bleeds the aetiologies are identical and so we can use these terms interchangeably.
Such haemorrhages have a crescentic shape which demarcates the limit of the posterior vitreous detachment. The aetiology is commonly neovascularisation or complicated posterior vitreous detachment. Another common cause is a valsalva manoeuvre and so a careful history is helpful. Patients should be warned not to strain or exert themselves physically as there is a risk of penetration into the vitreous gel!
Flame shaped haemorrhages are found in the nerve fibre layer. The axons of ganglion cells in the nerve fibre layer shape the blood to reflect this flame type appearance.1 Presentations with flame haemorrhages include; hypertensive retinopathy, vein occlusion, AION, disc swelling amongst others. Commonly, the aetiology is hypertensive in origin. Thus, recording blood pressure is paramount when encountering this finding. An isolated finding of a flame shaped haemorrhage at the margin of a non-swollen optic disc raises the suspicion of normal tension glaucoma. This is a marker for the site of future nerve fibre and corresponding visual field loss. The location should be accurately documented and further investigations performed.
Haemorrhages with pale centres
Such retinal haemorrhages are eponymously termed Roth spots after a Swiss pathologist, Moritz Roth. He first described this type of haemorrhage in 1872 in patients with severe bacteraemia. In 1878 a German pathologist, Moritz Litten, coined the term Roth spots for these retinal haemorrhages and found them to be present in 80% of patients with Sub-acute Bacterial Endocarditis.2 There may be a serious underlying cause for such haemorrhages and thus a careful systemic enquiry is necessary. (Figure 1). This is discussed further in a case below.
Dot and Blot
These arise from the slightly deeper, pre-venular, capillaries. The compact middle layers of the retina give rise to the dot and blot-like appearance of these haemorrhages1. Often there is associated oedema and if the macula is involved may give rise to diminished acuity. Blot haemorrhages are often larger and darker. (Figure 3 and 4). If seen these should alert the examiner to search for other features of ocular ischaemia –namely venous changes, cotton wool spots and neovascularisation.
Sub-retinal haemorrhages arise between the neuro-sensory retina and retinal pigment epithelium (RPE).1 They are dark in colour and the retinal vasculature is clearly visible above, (retinal capillaries are not found any deeper than the inner nuclear/outer plexiform layer). There are no firm adhesions in this space and so the bleed can be large in area and variable in shape. Sub-RPE bleeds, (between RPE and Bruch’s membrane of the choroid), have a more confined arrangement as there are tight junctions between RPE cells.1 The aetiology of such haemorrhages can be found within the eye. By far, the commonest cause is choroidal neovascularisation with such haemorrhages found at the posterior pole, (figure 5). Other causes include trauma, tumours and retinal angiomas.
By working through the cases below we aim to demonstrate the importance of a logical and comprehensive approach towards retinal haemorrhages. We will demonstrate the importance of the history, the reasons for and relevance of a careful look at the fundus through a dilated pupil. As a general rule bilateral retinal abnormalities – although possibly asymmetric point towards an underlying systemic disease.
A 55 year old asymptomatic man was found to have scattered dot haemorrhages throughout all 4 quadrants in both eyes at a routine eye examination. His visual acuity is 6/6 in each eye. His past medical history includes hypercholestorlaemia and hypertension which are controlled on Simvastatin and Ramipril respectively.
At first glance this is typically background diabetic retinopathy. However, how can we be sure? What are the salient points we need in order to be confident we are not missing other diagnoses? As always, we must begin by looking at the front of the eye. We need to ensure there are no features of ocular inflammation by way of conjunctival injection, keratic precipitates, cells, posterior synechiae, iris transillumination defects and raised intra-ocular pressure. If these were present we would think along the lines of systemic inflammatory diseases/infections and look more carefully at the fundal picture. We should also note the presence or absence of vitritis. The retina should be carefully examined through a dilated pupil. Optic nerve head swelling or pallor should be looked for as this could suggest alternate pathology such as a vein occlusion or hypertensive retinopathy. Examine the vessels carefully and note the presence or absence of any arteritis or phlebitis which would suggest infective or inflammatory disease as the aetiology. Look also for any arterio-venous nipping or silver wiring suggesting hypertensive retinopathy.
Having convinced ourselves that the above changes are absent the differentials are narrowed somewhat. They would include diabetic retinopathy, slow flow retinopathy and ocular ischaemic syndrome – although here the patient would likely have a few symptoms such as ocular ache and anterior segment signs would also commonly be present.
What should we do with this patient? Where and how should they be referred? If the patient is symptomatic for diabetes - polyuria, polydipsia, weight loss etc. then they should see their practice nurse or GP for an urgent fasting glucose and HbA1c. No onward ophthalmic referral would be indicated and the patient would be seen by the diabetic retinopathy screening service. However, if the patient is asymptomatic a prudent approach would be to ask the GP to review the patient to assess cardiovascular risk factors. Optometrists should ask the GP to consider a full blood count, ESR, fasting glucose, lipid profile looking for diabetes and hyperviscosity. An outpatient ophthalmology appointment with the results to the above should be requested.
However, if there are features of ocular inflammation, peri-vascular changes, optic nerve concerns, non-refractive visual loss, alongside retinal dot haemorrhages; a discussion with the on-call ophthalmology doctor is essential for appropriate management.
An 8 year old boy presents for a routine examination. There are no ophthalmic symptoms and mum tells you that he has an appointment with his GP next week as he has been having recurrent infections and is also losing weight. On dilated fundal examination he has widespread flame haemorrhages with pale centres.
Clinically, the fundal findings are not difficult to find. There will be flame-shaped haemorrhages with yellowish centres scattered in all 4 quadrants. The reason for this appearance has been the cause of much argument in the literature, however, it is likely that rupture of capillaries followed by adhesion of platelets and the formation of a platelet-fibrin complex gives rise to the white centre.2
Unless managed appropriately the underlying cause can be life threatening. When encountering asymptomatic pathology it is prudent to step back and start from the history again. It is essential to ask about symptoms of fever, rash, weight loss, tiredeness, and shortness of breath. Then look for signs of anaemia in the conjunctiva. As optometrists you will not be expected to perform a general physical examination but any grossly abnormal signs such as a widespread rash can be easily noted.
The diagnosis here is likely to be leukaemia or lymphoma and the reasons for the symptoms are due to a fall in red cells (tiredness, shortness of breath), effective white cells (recurrent infections) and platelets (petechial rash). If this boy were to wait until he sees his GP he may then have to wait for a blood test to confirm the diagnosis. Obviously this will lead to avoidable, potentially life-threatening, delay. Therefore, such patients should be referred urgently to the ophthalmologist on-call who can liaise with the paediatric team to arrange further tests.
The management here may sound strikingly obvious. However, the reasoning behind this and the approach to this situation will help when encountering other asymptomatic ocular pathology – thus allowing appropriate referral via the most time and cost effective path.
Finally, retinal haemorrhages found in a child always warrant further investigation. If there is no convincing history always consider physical abuse and urgently liaise with the on-call ophthalmologist or GP for advice.
A 76 year old lady presents with a sudden loss of central vision in her right eye. Her visual acuity is 6/60 in the right eye and 6/12 in the left eye. Fundal examination reveals a large sub-retinal haemorrhage at the macula in the right eye, with evidence of confluent drusen in the fellow eye.
The aetiology here is most likely to be choroidal neovascular membrane. It is essential to conduct a thorough examination of the posterior pole in the fellow eye to look for features of macular degeneration. This is to help confirm the likely diagnosis and also to look for any subtle features of exudative macular degeneration in the fellow eye. In accordance with NICE guidance this patient should be seen within 2 weeks and most hospitals run a rapid access macular service for such patients. Ensure you discuss smoking cessation if appropriate for the fellow eye, along with dietary advice and provide an Amsler chart for the fellow eye too.
Alternatively, if this patient presented to you following trauma and there was a large sub-retinal haemorrhage – perhaps not at the posterior pole, they should be discussed and reviewed by the ophthalmologist on-call. Globe integrity must be assessed for these patients. Do not manipulate the eye or try too hard to obtain intra-ocular pressure recordings for these patients. Provide a shield, if available, until they are seen within the secondary care service.
A 60 year old man with a 20 year history of type II Insulin-dependent diabetes mellitus (for 16 years) attends for a routine eye check. He has not engaged with the screening service and has not attended for retinopathy screening for 10 years. His corrected visual acuity is 6/6 in both eyes and there are no anterior segment signs. Dilated fundoscopy reveals dark blot haemorrhages in all 4 quadrants with venous changes in 3 quadrants in both eyes. There is no macular oedema. However, there is a pre-retinal haemorrhage in the right eye.
The diagnosis here is proliferative diabetic retinopathy in the right eye and very severe pre-proliferative diabetic retinopathy in the left eye.
However, in order to know how if this is mild, moderate, severe or very severe pre-proliferative retinopathy we must examine all 4 quadrants in detail and build up a picture. The Airlie House criteria are helpful in this respect and this was used in the Early Treatment of Diabetic Retinopathy Study. Simply, a 4:2:1 rule can be used. This refers to severe retinal haemorrhages in 4 quadrants, venous changes in 2 quadrants and extensive Intra-Retinal Microvascular Abnormalities (IRMA) in 1 quadrant. If any one of these changes is present it is severe pre-proliferative retinopathy and if 2 or more are present it is very severe pre-proliferative diabetic retinopathy, In those with severe changes 50% had proliferative retinopathy at 1 year and those with very severe, 75% had proliferative retinopathy at 1 year.3
Again, at first glance it can seem very easy to pass on the patient to secondary care. However, there are a few immediate problems. Firstly, the patient has not engaged with services. Therefore, referring via the GP may lead to a failure to attend. The patient may eventually attend when they lose vision from a vitreous haemorrhage, or a tractional retinal detachment, but by then we have missed an opportunity. Therefore, urgent PRP laser is needed and a same day appointment may be possible if the details of the situation are discussed in full with the ophthalmologist on-call.
Further, a letter should be sent to the GP highlighting the nature of this gentleman’s eye disease. Ideally, this would trigger a review of this patient’s blood pressure, lipid profile, HbA1C and medications. It may be helpful to point out the targets from a retinopathy point of view. Namely, a systolic blood pressure of less than or equal to 130mmHg in established retinopathy, consideration of an ACE inhibitor, a personalised HbA1c – normally between 48 and 58 mmol/mol, statins and fibrates.4
As an optometrist you may not be versed in the prescribing requirements for these drugs. However, as part of the diabetic team in the community, highlighting these benefits to the patients GP may help prevent sight loss and at the very least can optimise these contributing factors alongside referral to secondary care.
The cases above have been chosen because they illustrate the need to take a structured approach to retinal findings. Often, this means starting your sight test again – back from the history. Of-course, this is not a complete discussion on retinal haemorrhages. We have tried to create some general tips and rules to help guide management and investigation. However, we hope that these rules can be extrapolated to other cases that are encountered and that we have stimulated the reader to explore further. We also hope that by going through these cases it has illustrated the pivotal role optometrists can play in effective patient eye-care.
1. Diana L. Schechtman, Alan G Kabat. The many faces of a retinal haemorrhage. The pathophysiolosy of the retinal vascular system and the classification of a retinal haemorrhage aids in diagnosis. Available on-line at: http://www.optometricmanagement.com/articleviewer.aspx?articleid=101343
2. Roland Ling, Bruce James. White-centred retinal haemorrhages (Roth spots). Postgrad Med J 1998;74:581-582
3. Davis MD, Fisher MR, Gangnon RE et al. Risk factors for high risk proliferative diabetic retinopathy and severe visual loss: Early treatment Diabetic Retinopathy Study. Invest Ophthalmol Vis Sci 1998;39:233-252
4. The Royal College of Ophthalmologists – Diabetic Retinopathy Guidelines, December 2012. Available on-line at: http://www.rcophth.ac.uk/page.asp?section=451§ionTitle=Clinical+Guidelines