The presence of black bone spicule-shaped pigmentation in the peripheral retina and mottling of the retinal pigment epithelium in this fundoscopic image strongly suggests the presence of retinitis pigmentosa, a hereditary condition that primarily affects the rods and peripheral retina. Symptoms typically include night blindness and tunnel vision due to the loss of peripheral vision. Hypertensive retinopathy, on the other hand, is characterized by arteriolar narrowing and AV nipping in the early stages, with flame and blot hemorrhages that can form a macular star pattern. Papilloedema is seen in advanced cases. Non-proliferative diabetic retinopathy is characterized by microaneurysms, blot hemorrhages, hard exudates, cotton wool spots, and venous beading or looping, without any evidence of retinal neovascularization or fibrous tissue. Proliferative diabetic retinopathy, on the other hand, is characterized by retinal neovascularization, usually around the optic disc or elsewhere (NVE), and occasionally by the presence of fibrous tissue anterior to the retinal layer.

Understanding Retinitis Pigmentosa

Retinitis pigmentosa is a condition that primarily affects the peripheral retina, leading to tunnel vision. The initial sign of this condition is often night blindness, which can progress to a loss of peripheral vision. Fundoscopy, a diagnostic test, reveals black bone spicule-shaped pigmentation in the peripheral retina and mottling of the retinal pigment epithelium.

Retinitis pigmentosa is often associated with other diseases such as Refsum disease, Usher syndrome, abetalipoproteinemia, Lawrence-Moon-Biedl syndrome, Kearns-Sayre syndrome, and Alport’s syndrome. Refsum disease, for example, is characterized by cerebellar ataxia, peripheral neuropathy, deafness, and ichthyosis.

It is important to understand the symptoms and associated diseases of retinitis pigmentosa to ensure early diagnosis and treatment.

Ethambutol toxicity as a cause of optic neuropathy

Optic neuropathy, characterized by loss of visual acuity and color vision, is a known side effect of ethambutol, a standard first-line treatment for tuberculosis. In this case, the patient’s symptoms are consistent with ethambutol toxicity, and the medication should be stopped immediately. Fundoscopy may be normal in the early stages of neuropathy, so referral to ophthalmology as an emergency is necessary.

Other potential causes of optic neuropathy, such as cytomegalovirus retinitis, retinal vein thrombosis, rifampicin toxicity, and toxoplasmosis, are less likely in this patient. These conditions would typically present with different symptoms and signs on fundoscopy. Therefore, ethambutol toxicity should be considered as the primary cause of optic neuropathy in this patient.

Severe non-proliferative diabetic retinopathy (NPDR) is indicated by the presence of microaneurysms, hard exudates, and blot haemorrhages in the fundus. In addition to optimizing glycemic control, antihypertensive and statin therapy, pan-retinal laser photocoagulation should be considered for severe NPDR.

Optimizing glycemic control is recommended for all patients with non-proliferative or proliferative diabetic retinopathy. Moreover, controlling blood pressure and lipid levels tightly may help slow the progression of diabetic retinopathy.

In patients with maculopathy, intra-vitreal VEGF inhibitor therapy is recommended, or it may be used in combination with pan-retinal laser photocoagulation to treat severe proliferative diabetic retinopathy, which may present with extensive neovascularization around the disc or elsewhere.

Routine eye screening every two years is incorrect. All patients aged 15 or over with diabetes should have routine diabetic eye screening at least once a year.

Trabeculectomy, the surgical intervention used to reduce intraocular pressure in acute angle-closure glaucoma, is not urgently required. Cupping or an increased vertical cup-to-disc ratio, which are not present in this patient, are the classic fundoscopic signs of glaucoma.

Understanding Diabetic Retinopathy

Diabetic retinopathy is a leading cause of blindness in adults aged 35-65 years-old. The condition is caused by hyperglycaemia, which leads to abnormal metabolism in the retinal vessel walls, causing damage to endothelial cells and pericytes. This damage leads to increased vascular permeability, which causes exudates seen on fundoscopy. Pericyte dysfunction predisposes to the formation of microaneurysms, while neovasculization is caused by the production of growth factors in response to retinal ischaemia.

Patients with diabetic retinopathy are typically classified into those with non-proliferative diabetic retinopathy (NPDR), proliferative retinopathy (PDR), and maculopathy. NPDR is further classified into mild, moderate, and severe, depending on the presence of microaneurysms, blot haemorrhages, hard exudates, cotton wool spots, venous beading/looping, and intraretinal microvascular abnormalities. PDR is characterized by retinal neovascularisation, which may lead to vitrous haemorrhage, and fibrous tissue forming anterior to the retinal disc. Maculopathy is based on location rather than severity and is more common in Type II DM.

Management of diabetic retinopathy involves optimizing glycaemic control, blood pressure, and hyperlipidemia, as well as regular review by ophthalmology. For maculopathy, intravitreal vascular endothelial growth factor (VEGF) inhibitors are used if there is a change in visual acuity. Non-proliferative retinopathy is managed through regular observation, while severe/very severe cases may require panretinal laser photocoagulation. Proliferative retinopathy is treated with panretinal laser photocoagulation, intravitreal VEGF inhibitors, and vitreoretinal surgery in severe or vitreous haemorrhage cases. Examples of VEGF inhibitors include ranibizumab, which has a strong evidence base for slowing the progression of proliferative diabetic retinopathy and improving visual acuity.

Sudden loss of vision can be a scary symptom for patients, but it can be caused by a variety of factors. Transient monocular visual loss (TMVL) is a term used to describe a sudden, temporary loss of vision that lasts less than 24 hours. The most common causes of sudden painless loss of vision include ischaemic/vascular issues, vitreous haemorrhage, retinal detachment, and retinal migraine.

Ischaemic/vascular issues, also known as ‘amaurosis fugax’, can be caused by a wide range of factors such as thrombosis, embolism, temporal arteritis, and hypoperfusion. It may also represent a form of transient ischaemic attack (TIA) and should be treated similarly with aspirin 300mg. Altitudinal field defects are often seen, and ischaemic optic neuropathy can occur due to occlusion of the short posterior ciliary arteries.

Central retinal vein occlusion is more common than arterial occlusion and can be caused by glaucoma, polycythaemia, and hypertension. Severe retinal haemorrhages are usually seen on fundoscopy. Central retinal artery occlusion, on the other hand, is due to thromboembolism or arteritis and features include afferent pupillary defect and a ‘cherry red’ spot on a pale retina.

Vitreous haemorrhage can be caused by diabetes, bleeding disorders, and anticoagulants. Features may include sudden visual loss and dark spots. Retinal detachment may be preceded by flashes of light or floaters, which are also symptoms of posterior vitreous detachment. Differentiating between these conditions can be done by observing the specific symptoms such as a veil or curtain over the field of vision, straight lines appearing curved, and central visual loss. Large bleeds can cause sudden visual loss, while small bleeds may cause floaters.

A sudden and painless loss of vision accompanied by severe retinal haemorrhages on fundoscopy is indicative of central retinal vein occlusion. The appearance of the affected area is often likened to that of a pizza with cheese and tomato toppings.

Understanding Central Retinal Vein Occlusion

Central retinal vein occlusion (CRVO) is a condition that can cause sudden, painless loss of vision. It is often associated with risk factors such as increasing age, hypertension, cardiovascular disease, glaucoma, and polycythemia. When a vein in the central retinal venous system is occluded, it can lead to widespread hyperemia and severe retinal hemorrhages, which are often described as a stormy sunset.

A key differential diagnosis for CRVO is branch retinal vein occlusion (BRVO), which occurs when a vein in the distal retinal venous system is blocked. This type of occlusion is thought to occur due to blockage of retinal veins at arteriovenous crossings and results in a more limited area of the fundus being affected.

While the majority of patients with CRVO are managed conservatively, there are indications for treatment in some cases. For example, patients with macular edema may benefit from intravitreal anti-vascular endothelial growth factor (VEGF) agents, while those with retinal neovascularization may require laser photocoagulation. Overall, understanding the risk factors, features, and management options for CRVO is essential for providing effective care to patients with this condition.

Treatment Options for Idiopathic Intracranial Hypertension

Idiopathic intracranial hypertension (IIH) is a condition that can lead to visual loss, which is the most serious complication. The treatment of choice for IIH is an urgent LP shunt. However, an alternative option is optic nerve fenestration. Unfortunately, there are no comparative studies between the two interventions.

In summary, when it comes to treating IIH, urgent LP shunt and optic nerve fenestration are the two main options. While LP shunt is the preferred treatment, optic nerve fenestration can also be considered. However, it is important to note that there is no clear evidence to suggest which option is better. Therefore, the decision on which treatment to use should be made on a case-by-case basis, taking into account the individual patient’s needs and circumstances.

This scenario pertains to partial loss of vision due to blurring, rather than complete loss of vision. Amaurosis fugax, which is often described as a ‘black curtain’ descending over the vision, is typically caused by retinal artery occlusions. However, in this case, the most probable cause of visual blurring is a retinal vein occlusion. The nasal retina corresponds to the temporal field. Risk factors for a retinal vein occlusion include hypertension and diabetes.

Sudden loss of vision can be a scary symptom for patients, but it can be caused by a variety of factors. Transient monocular visual loss (TMVL) is a term used to describe a sudden, temporary loss of vision that lasts less than 24 hours. The most common causes of sudden painless loss of vision include ischaemic/vascular issues, vitreous haemorrhage, retinal detachment, and retinal migraine.

Ischaemic/vascular issues, also known as ‘amaurosis fugax’, can be caused by a wide range of factors such as thrombosis, embolism, temporal arteritis, and hypoperfusion. It may also represent a form of transient ischaemic attack (TIA) and should be treated similarly with aspirin 300mg. Altitudinal field defects are often seen, and ischaemic optic neuropathy can occur due to occlusion of the short posterior ciliary arteries.

Central retinal vein occlusion is more common than arterial occlusion and can be caused by glaucoma, polycythaemia, and hypertension. Severe retinal haemorrhages are usually seen on fundoscopy. Central retinal artery occlusion, on the other hand, is due to thromboembolism or arteritis and features include afferent pupillary defect and a ‘cherry red’ spot on a pale retina.

Vitreous haemorrhage can be caused by diabetes, bleeding disorders, and anticoagulants. Features may include sudden visual loss and dark spots. Retinal detachment may be preceded by flashes of light or floaters, which are also symptoms of posterior vitreous detachment. Differentiating between these conditions can be done by observing the specific symptoms such as a veil or curtain over the field of vision, straight lines appearing curved, and central visual loss. Large bleeds can cause sudden visual loss, while small bleeds may cause floaters.

Homocysteinuria, Cystinuria, Cystinosis, Ehlers Danlos, and Marfan’s Syndrome are all inherited disorders with distinct characteristics and modes of inheritance. Homocysteinuria is caused by a deficiency in the enzyme cystathionine beta synthetase, leading to impaired metabolism of methionine. Patients with homocysteinuria typically present with a marfanoid body habitus, kyphoscoliotic spine, learning disabilities, and a downward dislocation of the lens. Cystinuria is a rare stone-forming disease of the kidneys resulting in the loss of renal reabsorption of cystine and other amino acids. Cystinosis is a lysosomal storage disorder that leads to the accumulation of cysteine in various tissues, particularly the kidneys. Ehlers Danlos is an inherited disorder of joint hypermobility caused by a variety of subtypes with varying genetic modes of inheritance. Marfan’s Syndrome is characterized by upward dislocation of the lens, which is not seen in this patient’s presentation. Physiotherapy and occupational therapy are the mainstay of managing Ehlers Danlos, while treatment for cystinuria involves urinary alkalinisation and cystinosis is treated with cystine-depleting therapy and adequate hydration. Renal replacement therapy and transplantation are the ultimate treatments for cystinosis.

The patient is displaying symptoms of left optic neuritis, but there are no other central lesions present clinically or radiologically that would indicate a diagnosis of multiple sclerosis. Therefore, starting neuromodulatory therapy with interferon is not necessary. While visual recovery from optic neuritis typically takes weeks to begin, prompt treatment can speed up the process.

In a recent study called the Optic Neuritis Treatment Trial (ONTT), researchers compared the effectiveness of oral prednisolone and intravenous methylprednisolone in treating acute optic neuritis. The results showed that intravenous methylprednisolone led to faster visual recovery and reduced the risk of developing multiple sclerosis after 2 years, while oral prednisolone did not provide any benefits. However, intravenous steroids did not improve visual function compared to a placebo after 2 years. There is currently no evidence to support the use of intravenous immunoglobulin in treating optic neuritis.

Understanding Optic Neuritis: Causes, Features, Investigation, Management, and Prognosis

Optic neuritis is a condition that causes a decrease in visual acuity in one eye over a period of hours or days. It is often associated with multiple sclerosis, diabetes, or syphilis. Other features of optic neuritis include poor discrimination of colors, pain that worsens with eye movement, relative afferent pupillary defect, and central scotoma.

To diagnose optic neuritis, an MRI of the brain and orbits with gadolinium contrast is usually performed. High-dose steroids are the primary treatment for optic neuritis, and recovery typically takes 4-6 weeks.

The prognosis for optic neuritis is dependent on the number of white-matter lesions found on an MRI. If there are more than three lesions, the five-year risk of developing multiple sclerosis is approximately 50%. Understanding the causes, features, investigation, management, and prognosis of optic neuritis is crucial for early diagnosis and effective treatment.

Visual field defects are a common occurrence in clinical practice and MRCP part 2. The first thing to note is that the presentation is monocular, indicating that the lesion is located anterior to the optic chiasm. Additionally, the fundoscopy is unremarkable, which is not typical for a retinal infarct caused by central or branch retinal artery occlusion.

In cases of acute retinal infarct, a classic cherry red spot, pale fundus, and possible visualization of the embolus are usually observed. Since the lesion is located at the optic nerve, the cause must be determined, which could be optic neuritis, arteritic or non-arteritic anterior ischemic optic neuropathy. Optic neuropathy usually results in a correlated deficit in visual acuity with color vision, which distinguishes it from optic neuritis where color vision is often better preserved.

Finally, the patient’s ESR is normal, and there are no local or systemic signs of vasculitis, particularly temporal arteritis. Furthermore, the patient has multiple vascular risk factors, making non-arteritic ischemic anterior optic neuropathy the most likely diagnosis. Management involves optimizing vascular risk factors, and there is limited evidence for a tapering dose of oral prednisolone. Most patients can expect to improve by 3 lines of a Snellen chart within 6 months.

Sudden loss of vision can be a scary symptom for patients, but it can be caused by a variety of factors. Transient monocular visual loss (TMVL) is a term used to describe a sudden, temporary loss of vision that lasts less than 24 hours. The most common causes of sudden painless loss of vision include ischaemic/vascular issues, vitreous haemorrhage, retinal detachment, and retinal migraine.

Ischaemic/vascular issues, also known as ‘amaurosis fugax’, can be caused by a wide range of factors such as thrombosis, embolism, temporal arteritis, and hypoperfusion. It may also represent a form of transient ischaemic attack (TIA) and should be treated similarly with aspirin 300mg. Altitudinal field defects are often seen, and ischaemic optic neuropathy can occur due to occlusion of the short posterior ciliary arteries.

Central retinal vein occlusion is more common than arterial occlusion and can be caused by glaucoma, polycythaemia, and hypertension. Severe retinal haemorrhages are usually seen on fundoscopy. Central retinal artery occlusion, on the other hand, is due to thromboembolism or arteritis and features include afferent pupillary defect and a ‘cherry red’ spot on a pale retina.

Vitreous haemorrhage can be caused by diabetes, bleeding disorders, and anticoagulants. Features may include sudden visual loss and dark spots. Retinal detachment may be preceded by flashes of light or floaters, which are also symptoms of posterior vitreous detachment. Differentiating between these conditions can be done by observing the specific symptoms such as a veil or curtain over the field of vision, straight lines appearing curved, and central visual loss. Large bleeds can cause sudden visual loss, while small bleeds may cause floaters.