Should Aquaporin-4 Antibody Test Be Performed in all Patients With Isolated Optic Neuritis?

BACKGROUND: Optic neuritis (ON) may be the initial manifestation of neuromyelitis optica spectrum disorder (NMOSD). Aquaporin-4 antibody (AQP4 Ab) is used to diagnose NMOSD. This has implications on prognosis and is important for optimal management. We aim to evaluate if clinical features can distinguish AQP4 Ab seropositive and seronegative ON patients. METHODS: We reviewed patients with first episode of isolated ON from Tan Tock Seng Hospital and Singapore National Eye Centre who tested for AQP4 Ab from 2008 to 2017. Demographic and clinical data were compared between seropositive and seronegative patients. RESULTS: Among 106 patients (120 eyes) with first episode of isolated ON, 23 (26 eyes; 22%) were AQP4 Ab positive and 83 (94 eyes; 78%) were AQP4 Ab negative. At presentation, AQP4 Ab positive patients had older mean onset age (47.9 ± 13.6 vs 36.8 ± 12.6 years, P < 0.001), worse nadir VA (OR 1.714; 95% CI, 1.36 to 2.16; P < 0.001), less optic disc swelling (OR 5.04; 95% CI, 1.682 to 15.073; p = 0.004), and higher proportions of concomitant anti-Ro antibody (17% vs 4%, p = 0.038) and anti-La antibody (17% vs 1%, p = 0.008). More AQP4 Ab positive patients received steroid-sparing immunosuppressants (74% vs 19%, p < 0.001) and plasma exchange (13% vs 0%, p = 0.009). AQP4 Ab positive patients had worse mean logMAR VA (visual acuity) at 12 months (0.70 ± 0.3 vs 0.29 ± 0.5, p = 0.051) and 36 months (0.37±0.4 vs 0.14 ± 0.2, p = 0.048) follow-up. CONCLUSION: Other than older onset age and retrobulbar optic neuritis, clinical features are non-discriminatory for NMOSD. We propose a low threshold for AQP4 Ab serology testing in inflammatory ON patients, particularly in high NMOSD prevalence populations, to minimize diagnostic and treatment delays.

An Unusual Case of Concurrent Central Retinal Vein and Cilioretinal Artery Occlusion in a Healthy Patient.

It is rare for young, healthy patients to have retinal venous or arterial occlusions and even rarer for both to occur in concert. Such an occurrence should prompt a rapid and extensive workup to prevent further complications. We present our patient, a 37-year-old Lebanese male, who reported a 3-day history of blurring of vision in his left eye. He had no medical or ocular history and is a nonsmoker. Examination of the left fundus revealed inferior macular edema and retinal whitening associated with tortuous retinal veins. He was diagnosed with a combined central retinal vein and cilioretinal artery occlusion. Emergency treatment was done for an acute arterial occlusion. Embolic and thrombotic causes were excluded with investigations. The only positive result was homozygosity for 677C>T mutation of the 5,10 methylenetetrahydrofolate reductase (MTHFR) enzyme gene. MTHFR enzyme breaks down homocysteine, which is atherogenic and prothrombotic. This mutation can lead to a prothrombotic state, precipitating this occurrence. In fact, the Lebanese population is known to have the highest incidence of such mutations, but there are surprisingly few reports on retinal vascular occlusions attributed to this. He was promptly treated with antiplatelet therapy, possibly preventing a full-blown central retinal vein occlusion. After 4 weeks, his vision improved to 6/6 bilaterally. Examination showed less tortuous veins, no more retinal whitening, resolution of macula edema and visual field defect. Hyperhomocysteinemia can be significant in patients without ischemic risk factors. It is vital to manage these patients promptly, preventing future sight and life-threatening events.

Anticoagulation for Radiation-Induced Optic Neuropathy.

Radiation-induced optic neuropathy (RION) is a severely disabling complication of radiotherapy, without any known effective treatment. Three patients, one female and two males, aged 60, 34, and 45 years, respectively, developed progressive deterioration in visual acuity over 1 month, 8 years, and 2 months, starting 3, 12, and 9 years after radiotherapy for nasopharyngeal carcinoma. They received 70.15, 60.89, and 56.11 Gy over a period of 6-7 weeks, with fractionated doses of 2, 1.79, and 1.81 Gy, respectively. Ophthalmological examination revealed a relative afferent pupillary defect in the latter 2 patients, best-corrected visual acuity was 6/12 or better in all. Visual field charting showed a superior altitudinal field defect in the first two, and generalised visual loss in the third patient in the symptomatic eyes. Anticoagulation with heparin bridging and oral warfarin with an INR target of 2.0-3.0 was commenced within 2 months of symptom onset. All showed improvement in visual fields within 2 weeks, and remained stable for at least 2 years while on warfarin. Our encouraging findings will need to be confirmed in a randomised controlled clinical trial.

Eye Globe Abnormalities on MR and CT in Adults: An Anatomical Approach.

Eye globe abnormalities can be readily detected on dedicated and non-dedicated CT and MR studies. A primary understanding of the globe anatomy is key to characterising both traumatic and non-traumatic globe abnormalities. The globe consists of three primary layers: the sclera (outer), uvea (middle), and retina (inner layer). The various pathological processes involving these layers are highlighted using case examples with fundoscopic correlation where appropriate. In the emergent setting, trauma can result in hemorrhage, retinal/choroidal detachment and globe rupture. Neoplasms and inflammatory/infective processes predominantly occur in the vascular middle layer. The radiologist has an important role in primary diagnosis contributing to appropriate ophthalmology referral, thereby preventing devastating consequences such as vision loss.

Glare in a Case of a Craniopharyngioma.

Glare is commonly encountered in patients with corneal disease, uveitis, or retinal problems. Rarely, it may be a presenting manifestation of more sinister conditions such as chiasmal lesions. We present the case of a 42-year-old male who complained of glare for 2-3 months. There was neither headache nor blurring of vision. His neuro-ophthalmological examination was within normal limits except for slight decrease in colour contrast of the upper temporal dots of the red-dot perimetry chart. Automated visual fields showed a central scotoma on the right eye and a temporal-inferior field defect on the left. He underwent neuro-imaging, which revealed a suprasellar cystic mass, most likely a craniopharyngioma. Referral to the neurosurgeon was made who performed supraorbital keyhole surgery. Intraoperative findings showed a cystic mass stuck bilaterally on the optic nerves, carotids, and optic chiasm with the pituitary stalk deviated to the right side. Histopathology report revealed a craniopharyngioma, adamantinomatous variant. One month post excision, the patient showed improvement in his visual functions.

Magnetic resonance imaging in acute optic neuritis in Singapore.

INTRODUCTION: The Optic Neuritis Treatment Trial (ONTT) has established that the magnetic resonance imaging (MRI) findings at the time of presentation of optic neuritis (ON) is the strongest indicator of the development of multiple sclerosis (MS). Reports from Singapore as well as other Asian countries have indicated that these abnormalities are less frequently encountered compared to that reported by the ONTT. This paper aims to describe systematically the brain MRI as well as the optic nerve abnormalities in patients after an episode of acute optic neuritis. MATERIALS AND METHODS: Patients who presented with acute optic neuritis were retrieved from our prospective optic neuritis study and their MRI scans were reviewed and graded in accordance with the standardised classification employed in the ONTT. RESULTS: Fifteen of 24 patients had MRI brain and optic nerves performed during the acute episode. In the evaluation of brain abnormalities, 40% were classified as grade 0, 20% grade I, 20% grade II, 6.7% grade III and 13.3% grade IV. Optic nerve abnormalities were observed in 80% of cases. At study entry, 10 patients had idiopathic (monosymptomatic) ON, 3 had multiple sclerosis (MS), one each with infective and autoimmune optic neuritis, respectively. The single patient who developed MS at study completion presented with grade II brain abnormalities at the initial MRI. For those with idiopathic ON, our study revealed a higher percentage of grade 0-I brain changes as well as a lower lesion load compared to the ONTT.Lesion Load and grade was also lower in anterior optic neuritis compared with retrobulbar disease. CONCLUSION: Our study revealed a lower percentage of grade II-IV brain MRI abnormalities as well as less lesion load in idiopathic ON compared to the ONTT. This may be related to the lower prevalence of MS in our predominantly Asian population. As diagnostic tests and understanding of neuromyelitis optica or Devic's disease improves, we may see more patients being diagnosed with this condition, which may also explain our findings. Our data also showed that MRI grade and lesion load in cases of anterior ON was lower than for retrobulbar disease. MRI in ON has an essential role in characterising the disease, evaluating for associated brain lesions, and assessing prognosis in retrobulbar disease but may be less useful in anterior disease.

Residual neurovascular function and retinotopy in a case of hemianopia.

INTRODUCTION: For occipital cortex strokes resulting in vision disorders, questions about the viability of residual visual cortex remain. CLINICAL PICTURE: In a patient with a one-year-old, left, complete, homonymous hemianopia due to a right, posterior cerebral artery, ischaemic infarct, we assessed the visual cortex with fMRI retinotopic mapping prior to starting vision restoration therapy. OUTCOME: The patient was found to have residual neurovascular function and retinotopic representation in the surviving visual cortex around the infarcted area. CONCLUSION: The ability to respond to stimuli in part of the blind field, though not consciously perceived, suggests the potential for recovery.

The incidence of neuro-ophthalmic diseases in Singapore: a prospective study in public hospitals.

PURPOSE: To describe the incidence of neuro-ophthalmic diseases in a multi-ethnic Asian population in Singapore. METHODS: Prospective study in public hospitals in Singapore. All neuro-ophthalmic cases seen in four public sector hospitals over a 22-month period (September 2002 to June 2004) were identified using a standardized protocol. The 2004 Singapore population was used as a denominator to estimate annual incidence. The prevalence of ischemic risk factors (hypertension, diabetes, and hypercholesterolemia) among cases was compared to population data. RESULTS: A total of 1,356 patients with neuro-ophthalmic diseases were seen during the study period, of which 627 were new incident cases. The overall annual incidence of neuro-ophthalmic diseases was 9.81 per 100,000 (95% confidence interval, 8.80-10.90). The incidence increased with age. After controlling for age, the annual incidence was similar between men (10.75 per 100,000) and women (9.00 per 100,000), but was higher in Chinese (10.33 per 100,000) and Indians (9.34 per 100,000) than in Malays (6.62 per 100,000). The three commonest specific neuro-ophthalmic conditions were abducens nerve palsy (1.27 per 100,000), anterior ischemic optic neuropathy (1.08 per 100,000) and oculomotor nerve palsy (0.91 per 100,000). The incidence of optic neuritis was 0.83 per 100,000. Compared with the Singapore general population, the prevalence of diabetes was significantly higher in people aged 40-59, while the prevalence of hypercholesterolemia was significantly higher in 60-69 year age group. CONCLUSION: In this study of public hospitals in Singapore, the incidence of neuro-ophthalmic diseases was higher in Chinese and Indians compared to Malays.

Orbital metastasis of renal cell carcinoma masquerading as cysticercosis.

Metastasis to the orbital soft tissues is relatively uncommon. We report a rare case of renal cell carcinoma with orbital metastasis as the first clinical manifestation. A 48-year-old-man presented with left proptosis and complete ptosis of three weeks duration. Radiological examination revealed a left intraconal heterogeneous cyst-like lesion with rim enhancement immediately deep to the left superior rectus muscle. Diagnosed as having orbital cysticercosis, he was prescribed oral albendazole and prednisolone. But there was no clinical improvement. An incisional biopsy performed showed metastatic poorly differentiated carcinoma. The patient complained of backache and weight loss in the interim. Magnetic resonance imaging (MRI) of the spine showed extensive vertebral metastasis to the thoracic and lumbosacral spine and the iliac bone, with an incidental detection of a large mass from the right kidney. Further MRI of abdomen and chest showed a large right renal mass presumed to be a renal cell carcinoma with extension into the right renal vein, intra-abdominal lymph nodes, and peritoneum. There were small nodules in the lung suggesting the possibility of pulmonary metastatic deposits. Renal cell carcinoma does not respond to chemotherapy, immunotherapy, or radiation; because of the disease's advanced stage, the patient received palliative treatment. There have been only two other reports in the literature of metastatic renal cell carcinoma in the orbit where the proptosis was the initial presenting feature similar to our case.

Visual hallucinations during visual recovery after central retinal artery occlusion.

BACKGROUND: Charles Bonnet syndrome is characterized by complex, formed visual hallucinations that occur in patients without psychiatric disorders. To the best of our knowledge, it has not been described following central retinal artery occlusion. OBJECTIVE: To describe 2 patients who experienced formed visual hallucinations characteristic of Charles Bonnet syndrome after sudden, severe visual loss precipitated by central retinal artery occlusion. PATIENTS: Two patients, aged 77 and 63 years respectively, experienced sudden deterioration of vision following central retinal artery occlusion. Formed visual hallucinations occurred in patient 1 six days later and in patient 2 two days later. RESULTS: The hallucinations appeared both within and at the borders of the patients' residual intact visual fields. They occurred during periods when the patients experienced partial visual recovery associated with enlargement of their visual fields. The visual recovery and hallucinations both ceased at the same time. CONCLUSIONS: We propose that the hallucinations are likely the result of deafferentation and their occurrence during visual recovery suggests that they are a correlate of visual system plasticity.