Your ophthalmologist will examine your eyes to confirm a histoplasmosis diagnosis. They will be looking for two things in particular:
- histo spots
- swelling of the retina, which signals the growth of new blood vessels that are not normal
Your doctor may have you use an Amsler grid to check for histoplasmosis symptoms such as wavy, blurry or dark areas in your vision.
Your ophthalmologist will dilate (widen) your pupils with eye drops. They will look at your retina and other areas in the back of the eye. Your ophthalmologist will look for fluid or blood vessels that are not normal. If you have these signs, your ophthalmologist will take special photographs of your eye. They use optical coherence tomography (OCT), OCT angiography, or fluorescein angiography to take these photographs.
OCT uses light waves to make detailed pictures of the area beneath the retina. OCT images show how thick the retina is. They can help your ophthalmologist find swelling and blood vessels that are not normal.
OCT angiography uses light waves to look at the blood vessels in the retina without needing a dye injection.
During fluorescein angiography, a dye is injected into a vein in your arm. The dye travels throughout the body, including your eyes. The dye highlights areas of the retina that are not normal.
A certain chemical can cause blood vessels that are not normal to grow under the retina. This chemical is called vascular endothelial growth factor, or VEGF. One method for treating histoplasmosis is to block VEGF.
Several anti-VEGF drugs can block the trouble-causing VEGF. Blocking VEGF reduces the growth of blood vessels and slows their leakage. This helps to slow vision loss and in some cases improves vision.
Your ophthalmologist injects the anti-VEGF drug into your eye in an outpatient procedure. Before the procedure, your ophthalmologist will clean your eye to prevent infection. They will numb your eye with anesthetic eye drops. You may receive multiple anti-VEGF injections over the course of many months. Repeat anti-VEGF treatments are often needed for continued benefit.
Laser treatment for histoplasmosis is usually done as an outpatient procedure. You will have this treatment either in the doctor’s office or at the hospital.
The laser beam in this procedure is a high-energy, focused beam of light. It produces a small burn when it hits the area of the retina where you need treatment. The burn destroys the blood vessels that are not normal. This prevents further leakage, bleeding and growth.
After laser treatment, your vision may be more blurry than before treatment. But this will often stabilize within a few weeks. A scar forms where the laser burned your retina. The scar makes a permanent blind spot that might be noticeable in your field of vision.
Laser treatment does not cure histoplasmosis. It reduces the chance of blood vessels spreading and causing more harm to your vision. If these blood vessels do return, you may need more laser surgery.
Your ophthalmologist may treat you with steroid injections. These shots in the eye reduce swelling due to histoplasmosis.
Histoplasmosis remains a threat to your vision for your lifetime. It is important to have regular checkups with your ophthalmologist to detect any problems as early as possible.