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- Ocular Myasthenia Gravis (OMG)
Ocular myasthenia gravis (OMG) is a rare autoimmune condition of the neuromuscular system specializing in causing weakness of the muscles responsible for eye movements and such movements including eye muscle, eye lid elevation, and in some cases, eye movement rotation. Protheragen provides full-service solutions towards the creation of therapies and diagnostics for Ocular Myasthenia Gravis (OMG).
Ocular Myasthenia Gravis (OMG) is an autoimmune form of the neuromuscular disorder Myasthenia Gravis (MG) characterized by autoantibodies directed against acetylcholine-evoking proteins at the neuromuscular junction. OMG largely involves extraocular muscles and manifests as ptosis (dropping of the upper eyelid) and diplopia (double vision). OMG remains one of the most important problems because of its heterogeneous presentation and possible conversion to generalized myasthenia gravis (GMG). The annual incidence of OMG is reported to be around 1.13 per 100,000, and almost 50% of these cases present with ocular signs as the first feature.
Fig. 1 The pathophysiology of myasthenia gravis. (Behbehani R., 2023)Electrophysiological Diagnostics
Electrophysiological tests play a key role in confirming the diagnosis of OMG, especially in cases that are seronegative. Repetitive nerve stimulation (RNS) is one of the tests which assess the decremental muscle reaction to repetitive stimulation of a nerve. But its sensitivity in OMG is low, with abnormal results 30–50% of the time. Single-fiber electromyography (SFEMG) is a more sensitive method which analyzes variability of the action potential intervals (jitter) between muscle fibers. As far as OMG is concerned, SFEMG has offered diagnostic sensitivity and specificity numbers which are highly valuable in practice: 88-92% and 80%, respectively.
Pharmacological Diagnostics
Pharmacology examines the impact of muscle function using acetylcholinesterase inhibitors, specifically looking into the impacts of the edrophonium test. Despite its historic role, the test has low sensitivity and is prone to false positives which make it outdated compared to other modern diagnostic techniques. Currently, oral pyridostigmine trials have taken its place, as an improvement in muscle function signifies a positive outcome. This form of pharmacology does help in supporting the diagnosis of OMG by showing how effectively increases in cholinergic stimulation can aid in motor function.
| Therapeutics | Target | Description | Stage |
| Pyridostigmine | Acetylcholinesterase | Symptomatic therapy that enhances neuromuscular transmission by increasing acetylcholine availability. Effective for mild ocular symptoms, particularly ptosis. | Approved |
| Prednisone | Immune System | Oral corticosteroids are used to reduce inflammation and improve muscle function. Effective in resolving diplopia and improving orthoptic measurements. | Approved |
| Azathioprine | Immune System | The second-line immunosuppressive agent used to reduce steroid dependence and maintain long-term disease control. | Approved |
| Mycophenolate Mofetil | Immune System | The second-line immunosuppressive agent used in cases where corticosteroids are insufficient or contraindicated. | Approved |
| Methotrexate | Immune System | The second-line immunosuppressive agent used to manage refractory cases. | Approved |
| Cyclosporine | Immune System | The second-line immunosuppressive agent used for long-term management of OMG. | Approved |
| Tacrolimus | Immune System | The second-line immunosuppressive agent used to manage refractory cases. | Approved |
| Rituximab | B Cells (CD20) | Monoclonal antibody targeting CD20-positive B cells, effective in MuSK-positive myasthenia. | Approved |
| Eculizumab | Complement System (C5) | A monoclonal antibody inhibiting the terminal complement pathway, effective in AChR-positive myasthenia. | Approved |
| Botulinum Toxin | Neuromuscular Junction | Used for cosmetic and visual rehabilitative purposes in cases with strabismus. | Approved |
Disclaimer: Protheragen focuses on providing preclinical research services. This table is for information exchange purposes only. This table is not a treatment plan recommendation. For guidance on treatment options, please visit a regular hospital.
Protheragen provides a full suite of services dedicated to the development of diagnostics and therapeutics for Ocular Myasthenia Gravis (OMG). Our capabilities encompass the entire spectrum, from the identification and validation of biomarkers to the creation of cutting-edge therapeutic solutions.
Protheragen's preclinical research services are meticulously crafted to expedite the development of effective therapeutics for Ocular Myasthenia Gravis (OMG). Leveraging our state-of-the-art facilities and seasoned scientific team, we offer a powerful and reliable platform for conducting rigorous preclinical studies. If you are interested in our services, please feel free to contact us.
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