Ocular Histoplasmosis Syndrome: The Science Versus the Experience

Biology 103
2002 First Paper
On Serendip

Ocular Histoplasmosis Syndrome: The Science Versus the Experience

MaryBeth Curtiss

Ocular Histoplasmosis Syndrome is a growth in abnormal blood cells under the retina induced by exposure to a particular kind of histo fungus. Though the manifestation of this syndrome in the eyes is rare, a significant portion of the population has been exposed to this fungus. As the syndrome develops, the part of the retina responsible for close, sharp vision deteriorates and eventually, without treatment this can become complete blindness aside from peripheral vision.

It is extremely rare that the histo fungus affects the eyes. It is most common that the fungus manifests itself in the lungs, thus creating a lung infection that appears like tuberculosis (3). This infection, unlike the ocular infection, is easily treatable with an anti-fungal prescribed medication. Though fungal infections from Histoplasma capsulatum are more unusual in the eyes than the lungs, OHS is the most common cause of blindness in adults aged 20 to 40 (5). On the contrary, when the fungus reaches the eyes, the damage is irreversible and often difficult to detect and diagnose.

This progression, however, is not readily detectible in a routine eye check-up and requires a specific test involving close examination and pupil dilation. The examiner can, however, detect damage to the macula, or the central part of the retina, by presenting the patient with an "Amsler grid" and judging how the patient sees it and if the patient's vision has been affected (2). The examiner may also notice tiny histo spots or swelling of the retina(1). Once the disease has begun to develop, it is only treatable through surgical means, more specifically, laser photocoagulation of the retina cells (2). This recoagulation process only prevents future vision loss and does not correct what has already been lost. This surgery s also only effective if the eye's fovea has not been damaged and only if the surgeon is able to eliminate all destructive cells in the retina (2).

Such was the progression of the disease in my uncle's eyes about ten years ago. His histoplasmosis went undetected and eventually grew into partial blindness. However, my uncle's experience defied the typical progression in some ways. Firstly, the destructive cells were never detected, though he regularly visited an eye doctor. The deterioration continued until it again defied the typified OHS case, and he became completely blind in his right eye. Generally, the histo cells only affect the center of the retina, the macula (1). In addition, the laser photocoagulation surgery did not stop the progression of blindness, but delayed it. Like common cases of ocular histoplasmosis, he did retain peripheral vision in his left eye. My uncle, however also defied the odds of OHS sufferers, and, though he had some of the most extensive progression of the infection, continued to live his life the way he always had. He became an active, and often victorious member of our local Blind Golfers Association and continued to play basketball, watch sports, read as best he could, and compete in his gym's activities.

Doctors later speculated that the histo fungus could have been picked up in any of Bud's travels, through the "Histo Belt" through the central United States, or many years earlier in his travels to China and Japan. Though his travels in Asia were many years earlier, some of the doctors have suggested that the fungal cells could have remained dormant through the years until they surfaced in the early 90s. This incubation period is much different from that of the lung affliction, as this infection's symptoms appear within two weeks (4). Research and information is constantly changing concerning our understanding of histoplasmosis, when my uncle was first diagnosed, much of the information he was given was speculative and the surgery he received was still experimental.

Researching histo fungus, histoplasmosis, and ocular histoplasmosis syndrome raised more questions than provided answers. Why the difference in symptoms? Why the difference in time for symptoms? Why the eyes and lungs? Why are the lungs easily treatable and the eyes so difficult? One thing we may conclude, however is that everyone should be tested for this infection, as it is the most common cause of blindness for young and middle-aged adults and incurable, but easily delayed.

References

1) Ocular Histoplasmosis Syndrome, Useful for a general overview

2) Effectiveness of Laser Surgery, Procedure and statistics

3) Frequently Asked Questions, Information on the lung infection

4) Frequently Asked Questions, More general iformation

5) Histoplasmosis, Some new information

Comments made prior to 2007

The only treatment that has been able to arrest the scarring in my eyes is to take predisone tablets up to 50mg the first three days and then taper off. I had one retinal specialist advice me to not take this medication when I could see changes but he could not see the reactivity. I didn't use the medicene for a month and suffered more distruction of my macula and bindness around my left eye's blind spot. Finally I just started taking the medicene a former doctor had given me and immediately started seeing improvement. I have had about six reoccurances since 1968. I am 57. Even though prenisone is a potentially dangerous drug, I have to take it when the histo reactivates. It reactivates when I get really stressed. I continue daily to work on destressing my life. Most of the damage is in my left eye, but I have two small spots in my right eye. My right blind spot has some damage around it, but not as bad as the left eye. My blind spot in my left eye is as large as one-third of this paper. Maybe this info will be helpful to someone ... Loretta Taylor, 17 April 2006