Vision conditions

Myopia, or nearsightedness, is a refractive error that occurs when the eye does not bend or refract light properly to a single focus to see images clearly. At a distance vision is blurred but near it is sharp. This is due to an eye that is not long enough or too powerful. When a person is myopic, they see better near than far. Learn more about myopia here.

Hyperopia also called hypermetropia or farsightedness, is a common refractive error, for which people can see distant objects very well, but have difficulty focusing on objects that are up close. It is the opposite of myopia. Learn more about hyperopia here.

Astigmatism is a refractive error for which people can see distant or near objects associated with a sensitivity to light. In other words, light fails to come to a single focus on the retina to produce a clear vision. Learn more about astigmatism here.​ is a refractive error for which people can see distant or near objects associated with a sensitivity to light. In other words, light fails to come to a single focus on the retina to produce a clear vision. Learn more about astigmatism here.

The symptoms of presbyopia are different of those of hyperopia. The two conditions have different causes: hyperopia occurs when the shape of the eye focuses light beyond the retina instead of on it, whereas presbyopia is due to the loss of flexibility in the lens. This loss of flexibility is due to aging. Learn more about presbyopia here.

Blinding Diseases

Most frequent questions and answers

Cataract is an eye disease in which the lens of the eye becomes progressively more opaque, resulting in blurred vision. Causes include aging, cortisone medication, trauma, diabetes, and many others. Symptoms include pinpoint vision and a feeling of continual fog that can go as far as blindness. Cataract represents 34.47% of the causes of global blindness (all ages) and continues to be the leading cause of blindness. Learn more about cataract here.

Glaucoma is a group of diseases that damage the eye’s optic nerve. This destruction process is characterized by an increase in eye pressure that often changes gradually and painlessly. Untreated, it leads to the total loss of sight. More about glaucoma here.

Onchocerciasis (river blindness) is a parasitic disease endemic in 30 African countries. The disease is caused by a worm which is transmitted through the bites of infected blackflies. The blackflies carry the immature form of the worm and transmit it from human to human. Within the human body, the female adult worm produces thousands of baby worms (microfilariae) a day. These microfilariae move through the skin and eye causing damages such as skin rashes, lesions, itching, skin depigmentation and sometimes blindness. The WHO recommended strategy for control of onchocerciasis is mass drug distribution in endemic areas with Merck produced Mectizan®. More about onchocerciasis here

People with diabetes may develop an eye disease called diabetic retinopathy. This is when high blood sugar levels cause damage to blood vessels in the retina. These blood vessels can swell, leak or close, stopping blood from passing through. Symptoms include blurred or fluctuating vision, impaired color vision and dark or empty areas in the vision. More about diabetic retinopathy here.

Trachoma is caused by a bacterial infection of the eye. The bacteriumChlamydia trachomatis is transmitted through contact with eye and nose discharge of infected people. The infection is easily spread through contact with an infected person’s hands or clothes or spread by flies. Being outside most of the time, children are particularly at risk. Repeated infections over time may lead to the eyelashes drawn in so that they rub on the surface of the eye, with pain and discomfort and permanent damage to the cornea. This is more prevalent in older age groups and eventually leads to irreversible blindness. The WHO recommended strategy to control trachoma is the SAFE strategy (Surgery, Antibiotics, Face washing and Environmental change), which consists of multiple interventions designed to reduce transmission, treat infection, and correct disease aftereffects. The Pfizer produced Azythromycine is the antibiotic massively distributed in endemic area.
More about trachoma here

Macular degeneration, also known as Age-Related Macular Degeneration (AMD or ARMD), is an abnormality with an increase in eye pressure. Symptoms are characterized by a blurred or no vision at all in the center of the visual field due to the slow destruction of the optic nerve that can lead to the total loss of sight. The progression of the disease is painless and can be either very fast or very slow. More about AMD here.

Non-Blinding Tropical Diseases

We focus on five Neglected Tropical Diseases (NTD) that can be controlled by large-scale distribution of proven safe and effective medicines to all the people living in the endemic areas. These are: Lymphatic filariasis (also known as elephantiasis), Onchocerciasis (also known as river blindness), Schistosomiasis (also known as snail fever or bilharzia), Soil-Transmitted Helminths and Trachoma.

OPC decided to incorporate three non-blinding diseases – Lymphatic filariasis, Schistosomiasis and Soil-transmitted Helminths – to its programs based on an ethical stand. Community drug distributors are trained, with support from OPC, to distribute drugs fighting blinding diseases and therefore they can be available to deliver medicines to prevent other diseases, especially if the same drug treats both conditions.

40% of the global NTD burden is in Africa. However, out of the 19 countries that have been validated as having eliminated one of the five diseases, only four are from Africa (Morocco [Trachoma, 2016], Togo [Lymphatic filariasis, 2017], Egypt [Lymphatic filariasis, 2018] and Ghana [Trachoma, 2018]).

Lymphatic filariasis (LF) is caused by infection with roundworm parasites. The adult worm only lives in the adult lymph system, which oversees body fluid balance and fights infections. The infection is transmitted to humans through the bites of mosquitoes. Long term infection with LF leads to painful and disfiguring enlargement of arms and legs of people of all ages. LF is therefore a physical and psychological disease that has a significant economic impact. The burden of LF is heavy since out of the 1 billion people worldwide at risk of infection, one third live in Africa; more than 120 million people are infected and 40 million live in Africa. The WHO recommended strategy for control of LF is mass drug distribution in endemic areas with Merck produced Mectizan®. More about lymphatic filariasis here

Schistosomiasis (SCH), a parasite-disease, develops when people are in contact with water contaminated by snails carrying the parasite. The parasite penetrates the body, colonizing blood vessels, and sometimes getting caught in body tissues which causes immune reactions and progressive damage to organs. Transmission occurs when people suffering from SCH contaminate freshwater sources with their excreta containing parasite eggs, which hatch in water. People most at risk are those in constant contact with water (fishermen, rice farmers, but also playing children). Children especially may suffer from poor growth, malnutrition and impaired cognitive development. Long lasting impact include chronic
irreversible diseases such a scarring of the liver, bladder cancer and kidney failure. The WHO strategy for disease elimination is mass drug distribution in endemic areas with GSK produced Praziquantel®.
More about schistosomiasis here

Approximately 24 percent of the world’s population is infected with soil-transmitted helminths (STH). STH is an infection caused by the intestinal parasites roundworms. The worms live in human intestines and affect nutrition by impairing the absorption of nutrients. Symptoms include intestinal pain, malnutrition, weakness and impaired growth and physical development. Children and women of childbearing age are particularly at risk. The WHO recommended strategy for control of STH is through
controlling illness by conducting periodic treatment of populations at risk in endemic areas with GSK
produced Albendazol®. More about STH here