Tanzanian endemic optic neuropathy (TEON) Eye Diseases Optic neuritis
Conditions
Interventions
Schedule of procedures:
Referral: by initial ophthalmologist to Dr Burgess, after first presentation to hospital eye services.
Screening: performed by Dr Burgess, at t
Sponsors
University of St Andrews
Eligibility
Sex/Gender
All
Inclusion criteria
Inclusion criteria: Case group: 1. Signed written consent from all participants, prior to undertaking any study procedures 2. Aged 10-34 years 3. The case definition of TEON, as per previous studies, is a bilateral optic neuropathy of subacute, progressive onset with best-corrected visual acuities of 6/9 or worse in both eyes, alongside an acquired colour vision deficiency, in the presence of temporal optic disc pallor (with OCT evidence of corresponding thinning) or optic disc hyperaemia 4. Cases who meet the case definition and have been referred to the Eye Units in Dar es Salaam for further assessment Control group: 1. Signed written consent from all participants prior to undertaking any study procedures 2. Aged 10-34 years 3. Participants who have had an ophthalmic history, examination and screening and satisfy the classification criteria for not being diagnosed with TEON 4. Controls will, where possible, be first-degree relatives of a case group participant
Exclusion criteria
Exclusion criteria: 1. Cataract in either eye 2. History of ocular trauma 3. Diagnosis of another ocular pathology except refractive error 4. Relative afferent pupillary defect 5. Signs and symptoms suggestive of raised intracranial pressure 6. Existing diagnosis of multiple sclerosis (or any other demyelinating condition) 7. Untreated hypertension 8. Unilateral disease 9. Significant needle phobia 10. Use of oral vitamin supplements 11. Use of amiodarone, linezolid, ethambutol, isoniazid, tetracycline spp, oral chloramphenicol, methotrexate, lithium, metronidazole or omeprazole
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| 1. Biomarkers of oxidative stress assessed by measuring levels of the following in blood of patients with TEON at baseline: 1.1. NO metabolites (nitrite, nitrate, RXNO) 1.2. H2S metabolites (sulfide, sulfate) 1.3. Redox regulation (total free thiols, free and bound LMW thiols [cysteine, glutathione, homocysteine], ascorbate/dehydroascorbate and 4-hydroxynonenal [4-HNE]) | — |
Secondary
| Measure | Time frame |
|---|---|
| 1. Presence of genetic mutations known to be associated with optic neuropathy in patients with TEON via peripheral venous blood sampling at baseline in both cases and first-degree relative controls 2. Serum level of vitamin D in blood of patients with TEON at baseline 3. Serum level of vitamin B12 in blood of patients with TEON at baseline 4. Serum level of thiamine in blood of patients with TEON at baseline 5. Sunlight exposure of patients with TEON assessed using a questionnaire at baseline | — |
Countries
Tanzania
Contacts
Public ContactFrederick Burgess
Outcome results
None listed