Glaucoma refers to a group of disease where the pressure inside the eye is sufficiently elevated to cause optic nerve damage, resulting in visual field defects. However glaucoma can occur with normal intraocular pressure.
Normal intraocular pressure (IOP) is between 10 and 20 mmHg. Some types of glaucoma can result in an IOP exceeding 70 mmHg, creating corneal edema and immediate loss of vision.
Considering the burden of glaucoma especially in developing countries, where people are not familiar with routine eye consultation; glaucoma patients consult at late stage, with irreversible loss of vision. Rapha Medical Clinic with the help of Ophthalmologist and Eye Surgeon, Prof Saiba Semanyenzi Eugene, they took the lead in educating people on this condition.
Glaucoma is the second commonest cause of blindness world-wide, and in Rwanda no accurate data is available. The bad thing about this eye disease is that people affected by this condition don’t complaint about any symptom; the complaint will come just at the ending stage of the disease.
The cause of glaucoma is not well understood, however it is thought to be due to raised eye pressure, reduced blood flow at the optic disc and also some genetic factors.
Even though the physiopathology of glaucoma is not well known; many hypothesis are concluding on genetic cause. Secondary glaucoma is due to series of causes: inflammation (uveitis, aphakia (absence of the lens), trauma, cataract, retinal ischemia, bleeding, previous surgery, tumors, medications (e.g. long-term topical corticosteroids), etc.
Glaucoma’s common risk factors include ocular hypertension, age above 40 year olds, race (black Africans are at five times greater risk than whites), positive family history and myopia.
Key: Damage to the optic disc in glaucoma patients! In glaucoma, nerve fibers transmitting visual information from the photoreceptors to the brain are lost, resulting in characteristic changes on the surface of the optic nerve as it leaves the eye (damage to the nerve fibers at the disk); causing irreversible loss of vision. An examination of the eye at the slit-lamp often tells immediately whether or not there is glaucoma by the shape of the optic disc.
- Normal Optic disc
- Glaucomatous optic disc
Confirmation of this condition is done by measuring the intraocular pressure, performing funduscopy and an automated visual field test. Early Diagnosis and treatment are so important to avoid irreversible blindness.
Source : Prof Dr Saiba Semanyenzi Eugene
- A patient undergoing visual field examination at Rapha Medical Clinic