Hypercholesterolemia, also called high cholesterol, is the presence of high levels of cholesterol in the blood. It is a form of hyperlipidemia (high levels of lipids in the blood), hyperlipoproteinemia (high levels of lipoproteins in the blood), and dyslipidemia (any abnormalities of lipid and lipoprotein levels in the blood).Elevated levels of non-HDL cholesterol and LDL in the blood may be a consequence of diet, obesity, inherited (genetic) diseases (such as LDL receptor mutations in familial hypercholesterolemia), or the presence of other diseases such as type 2 diabetes and an underactive thyroid.Cholesterol is one of three major classes of lipids produced and used by all animal cells to form membranes. Plant cells manufacture phytosterols (similar to cholesterol), but in rather small quantities. Cholesterol is the precursor of the steroid hormones and bile acids. Since cholesterol is insoluble in water, it is transported in the blood plasma within protein particles (lipoproteins). Lipoproteins are classified by their density: very low density lipoprotein (VLDL), intermediate density lipoprotein (IDL), low density lipoprotein (LDL) and high density lipoprotein (HDL). All the lipoproteins carry cholesterol, but elevated levels of the lipoproteins other than HDL (termed non-HDL cholesterol), particularly LDL-cholesterol, are associated with an increased risk of atherosclerosis and coronary heart disease. In contrast, higher levels of HDL cholesterol are protective.Avoiding trans fats and replacing saturated fats in adult diets with polyunsaturated fats are recommended dietary measures to reduce total blood cholesterol and LDL in adults.
Once a neurological problem has, therefore, been ruled out, the disorders reduced visual acuity without visible fundus abnormalities may be misdiagnosed as optic neuritis, dominant optic atrophy, amblyopia, or nonorganic visual disorder.The combination of weak amplitudes in the mfERG with no visible fundus abnormalities then rules out other explanations. For example, OMD presents negative for a full-field ERG while retinitis pigmentosa presents abnormal. Prognosis
Since the abnormality is not in the eye lens, the disease is not correctable with eyeglasses. Vision becomes dimmer over the course of years as the macula loses function. Eventually the patient may become legally blind. The peripheral vision field is preserved. In other words, OMD does not cause total blindness, due to the concentration of the degradation at the cone-rich (color-sensitive) region of the retina. No treatment is known to slow the progression. The speed of progression varies by case — even between donor and recipient of the mutation — and can last for 10 to 30 years. Future research
Because of the rarity of OMD, no clinical trials are in the pipeline as of January 2019. However, mutations in RP1L1 might play a role in retinitis pigmentosa (RP), raising hope for a spillover effect for OMD patients should an RP1L1-related treatment be developed for RP. Given the possible relation between ABCA4 and OMD, progress with Stargardt disease via gene therapy might have a spillover effect for OMD patients as well. Adeno-associated viral (AAV) vectors have been particularly successful in gene therapy of eyes and muscles.