COWL and DORN have shown conclusively by careful tests that the perception of light under the action of the X-ray, which has been described by some authors, belongs in the sphere of subjective light perception, the perceptions occurring even when the visual field is wholly dark. Therefore the reports of the favorable effect of the X-rays on some sorts of blindness are not deserving of credit.
Reference: Progress of ophthalmology. Arch Ophthalmol.1898;27:325.
A look at the past . . .. Arch Ophthalmol. 1999;117(3):396. doi:10.1001/archopht.117.3.396