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Light exposure from ophthalmology exams: An analysis of potential hazards

Another thing that has me worried is the bright lights I get subjected to in the form of ophthalmoscopy, slit lamp exam, and fundus photos. Those lights can be painful when they are too bright (which they usually are). I read that bright lights can cause apoptosis (cell death spiral) of the ganglion cells. Of course every doctor I ask says that the lights are not bright enough to cause apoptosis.

It would certainly be ironic if, in the course of following our disease, we are subjecting our eyes to proceedures that raise our presures and cause our ganglion cell layer to self destruct! But my gut tells me that to some degree, that is what is I am doing. ~ Bob

FitEyes member Molly C, with her excellent Internet searching skills, found a relevant paper:

Retinal light exposure from ophthalmoscopes, slit lamps, and overhead surgical lamps An analysis of potential hazards (PDF attached below)

This paper confirms that there is a reason to be concerned about the things Bob mentioned above. Here is the abstract:

The projected beam radiance of several common ophthalmologic instruments was measured, and potential hazard to the patient from light exposure was analyzed with reference to safety standards for coherent light.

The indirect ophthalmoscopes tested appear to be "safe" under moderate voltage settings, provided exposure is reasonably brief.

Slit-lamp biomicroscopy of the fundus, however, merits caution. It produces a three-times-higher retinal irradiance than the indirect ophthalmoscope.

Overhead surgical lamps produce a retinal irradiance about one-third that of the indirect ophthalmoscope (for clear media and dilated pupil). This could, be dangerous, since an operation may take long enough to exceed the maximal permissible exposure by several orders of magnitude.

Major design changes are indicated for surgical illuminators to extend the "safe time" to the 40 to 60 min range.

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