Retinopathy miasms

Retinopathy means disease of the retina. There are several types of retinopathy but all involve disease of the small retinal blood vessels.

Sign/ Symptoms

• Asymptomatic
• Vitreous hemorrhage
• Floaters, or small objects that drift through the field of vision
• Decreased visual acuity
• "Curtain falling" over eyes

Causes

Two types. Both types cause disease by altering the normal blood flow to the retina through different mechanisms. The retina is supplied by small vessel branches from the central retinal artery. Proliferative retinopathy refers to damage caused by abnormal blood vessel growth. Normally, angiogenesis is a natural part of tissue growth and formation. When there is an unusually high or fast rate of angiogenesis, there is an overgrowth of blood vessels called neovascularization. In the non-proliferative type, abnormal blood flow to the retina occurs due to direct damage or compromise of the blood vessels themselves. Many causes of retinopathy may cause both proliferative and non-proliferative types, though some causes are more associated one type.

Non-proliferative retinopathy

It is often caused by direct damage or remodeling of the small blood vessels supplying the retina, which is caused by include hypertension, premature infant, radiation, solar , sickle cell , and anemia (Vitamin B12 deficiency).

Proliferative retinopathy

It is the result of aberrant blood flow to the retina due to blood vessel overgrowth, or neovascularization. These pathologically overgrown blood vessels are often fragile, weak, and ineffective at perfusing the retinal tissues. These weak, fragile vessels are also often leaky, allowing fluids, protein, and other debris to leach out into the retina. They are also prone to hemorrhage due to their poor strength. This makes proliferative types of retinopathy more risky since vessel hemorrhaging often leads to vision loss and blindness. Many of the causes mentioned in non-proliferative retinopathy may also cause proliferative retinopathy at later stages. Angiogenesis and neovascularization tend to be a later manifestation of non-proliferative retinopathy. Many types of non-proliferative retinopathies result in tissue ischemia or direct retinal damage. The body responds by trying to increase blood flow to damaged retinal tissues. Diabetes mellitus, which causes diabetic retinopathy, is the most common cause of proliferative retinopathy in the world.

Other causes

Genetic mutations are rare causes of certain retinopathies and are usually X-linked including NDP family of genes causing Norrie disease, FEVR, and Coats disease among others. There is emerging evidence that there may be a genetic predisposition in patients who develop retinopathy of prematurity and diabetic retinopathy. Trauma, especially to the head, and several diseases may cause Purtscher's retinopathy. Physical exertion like weight lifting and aerobic exercise, coughing, sneezing, straining at stool, vomiting, sexual intercourse, blowing up balloons, blowing musical instruments, cardiopulmonary resuscitation or compression injuries may cause valsalva retinopathy.