The Q-switched Nd:YAG laser provides short, high peak power laser pulses at a wavelength that is eye-transmitting yet invisible. Not surprisingly, this laser is the source of many of the worst recorded laser eye injuries.

The conventional wisdom is injuries to the retina do not heal. However, in 'Long Term Evaluation of Two Bilateral Laser Eye Accident Cases' presented at the '99 International Laser Safety Conference in Orlando, Harry Zwick et. al. from the US Army Medical Research Department, Texas, reported that visual acuity can recover from severe macula laser damage.

In both eyes of one patient and one eye of the other, visual acuity and large-field contrast sensitivity showed sustained improvement within four months of the exposure. These improvements were consistent with the use of a region of the retina just eccentric of the fovea. In one case this transient adaption occurred over a period of a year. Zwick et. al. attributed this to either the plasticity of the visual cortex or to a re-orientation of the non-foveal photoreceptors. However, in both cases there were permanent blue colour discrimination losses at the macula. Acute steroid therapy may have assisted visual function recovery.

Despite surgery, one of the two victims was left with permanent limited vision in one eye, as a result of the formation of a retinal hole.

The overall conclusion of this work is that, given time, the eye can make better use of undamaged areas of the retina near the fovea. To optimise this process, and help prevent complications later, it is important that the victim is promptly referred for an ophthalmological opinion.

Pro Laser can provide an expert witness in the case of alleged laser eye injuries.