Real Time Acoustic Dosimetry For Corneal Collagen Crosslinking
A change in the response of the cornea to ultrasonic energy directed into the cornea is monitored during irradiation of the cornea to bring about corneal crosslinking. Because the change in ultrasonic response is correlated with the degree of crosslinking achieved, a desired degree of crosslinking can be achieved by terminating the irradiation when the change reaches a threshold. The change in ultrasonic response can be determined by taking a baseline measurement before irradiation and additional measurements during irradiation using the same ultrasonic transducer ( 47 ). The transducers may be carried on a device ( 30 ) resembling a contact lens which overlies the eye and which transmits the light used in the irradiation step to the eye.
1 . A device for applying irradiation and ultrasound to an eye of a subject comprising:
(a) a housing having an inwardly-facing surface adapted to rest on an anterior surface of the eye;
(b) an optical diffuser mounted to the housing, the diffuser having inner and outer surfaces facing inwardly and outwardly; and
(c) a ultrasonic transducer mounted to the housing and disposed outward of the diffuser so that the diffuser is disposed between the transducer and the eye when the housing rests on the anterior surface of the eye.
2 . A device as claimed in claim 1 wherein the ultrasonic transducer is coaxial with the diffuser.
3 . A device as claimed in claim 1 wherein the housing includes a peripheral portion facing inwardly, the peripheral portion defining the inner surface of the housing and, the inner surface being adapted to bear on the sclera of the eye and maintain the diffuser and the transducer in alignment with the cornea.
4 . A device as claimed in claim 3 wherein the peripheral portion is adapted to maintain a space between the diffuser and the cornea.