Phototherapy of the cornea: some aspects to be considered

To safeguard against and reduce possible harmful and undesired side effects of photon interaction with ocular structures during phototherapy of certain corneal diseases, precautionary measures should be taken. These include (1) Selection of the proper light source, strongly emitting in the effective spectral range. (2) Removal of potential harmful spectral bands which make no significant contribution to the therapeutic action. (3) Determination of the most optimal exposure energy (W/cm2). (4) Selection of the most optimal time-dose relationship. (5) Selection of the proper interval between vital staining and radiation exposure and considering possible repetition of therapeutic exposures. (6) Careful calibration of the light source to be used. (7) Adequate eye examination for visual acuity, pupillary diameter, signs of intraocular inflammation, mainly iritis with anterior chamber activity, and possible fundus pathology with special attention to maculopathy. These findings should be properly recorded before, during and after the period of phototherapy.