Histoplasma capsulatum is a type of fungus which is responsible for this condition. This disease occurs when the airborne spores gets into a person’s lungs. This spore is sometimes called as histo and it is introduced in the air while sweeping chicken coops, digging holes, ploughing the fields or when disturbing the soil.
This condition starts as a lung infection at first and it reaches the eye trough blood stream. When it reaches the eye, it causes serious eye condition known as presumed ocular histoplasmosis syndrome (POHS). This is one of the leading causes of vision loss in Americans belonging to the age group 20-40.
There are no clear symptoms at first. Common cold is just one of the symptom and it also disappears because our body’s immune system clears the infection. Histo spots or tiny scars appear on the infection site and this is the only way to know that you have the condition. This condition does not generally affect the vision. After some years complications develop and there is abnormal growth of blood vessels under the retina.
Some of the symptoms of POHS are distorted vision, straight lines appearing bent, size of objects appearing different, blank spots in vision, loss of brightness while seeing, flashes and flickering.
Histo spots and the retinal swelling are noticed by the ophthalmologist and Amsler grid is also used. The pupils are dilated and abnormal blood vessels are noted if any. Optical Coherence Tomography is also used by the ophthalmologist to take photographs.
Anti vegf treatmen is done to reduce the abnormal growth of blood vessels and to slow down the vision loss. Laser treatment is also one of the option to burn the blood vessels that are not normal, preventing bleeding and further leakage. Steroid injection is given as shots in the eye which helps to reduce swelling.