Method and apparatus for controlling accommodation and pupil size during an eye examination
A system for conducting an examination of the eyes of a subject includes an examination instrument which emits light at infrared wavelengths, and a shield. The shield provides shielding of the subject's eyes from visible wavelengths. At least a portion of the shield is transparent to the infrared wavelengths emitted by the examination instrument. A related method of conducting an eye examination on a subject includes the step of providing a shield which is transparent to infrared wavelengths but nontransparent to visible wavelengths. The method also includes the step of carrying out the examination with an instrument which is located on the examiner facing side of the shield and which emits the infrared wavelengths to which the shield is transparent. One variant of the method determines parameters relating to the subject's eyes and/or vision using only information considered to be valid, validity being based on the subject's pupil diameter.
1. A system for conducting an examination of the eyes of a subject, comprising:
an examination instrument which emits light at infrared wavelengths; and
a shield, at least a portion of which is transparent to the emitted infrared wavelengths and which provides shielding of the subject's eyes from visible wavelengths.
2. The system of claim 1 wherein the shield is a pair of glasses.
3. The system of claim 1 wherein the shield is a pane of material.
4. The system of claim 1 wherein the shield is a hood.
5. The system of claim 1 wherein the shield is a shadowbox having top, bottom, left and right panels which provide the shielding from visible wavelengths and having a rearward panel which provides the transparency to the emitted infrared wavelengths.
6. The system of claim 1 wherein the shield includes a mark which is not transparent to a subpectrum of the infrared wavelengths.
7. The system of claim 1 wherein the shielding from visible wavelengths is selectable.
8. The system of claim 7 comprising a processor for executing machine readable instructions, and wherein the processor selects or deselects the shielding from visible wavelengths in response to the instructions.
9. The system of claim 8 wherein the processor, operating in response to the instructions, carries out the steps of:
a) signaling the shield to transition from a first state of less shielding from visible wavelengths to a second state of greater shielding from visible wavelengths; and
b) operating the examination instrument after completion of the signaling step.
10. The system of claim 9 comprising:
c) signaling the shield to transition from the second state to the first state after completion of the operating step.
11. The system of claim 1 wherein the system includes:
an image source which is not in the line of sight between the subject and the instrument; and
an image display element which is in the line of sight between the subject and the instrument.
12. The system of claim 1 wherein the examination instrument includes:
an image source which is not in the line of sight between the subject and the instrument; and
an image display element which is in the line of sight between the subject and the instrument.
13. A method of conducting an eye examination on a subject comprising:
providing a shield which is transparent to infrared wavelengths but nontransparent to visible wavelengths, the shield having a subject facing side and an examiner facing side; and
carrying out the examination with an instrument which is located on the examiner facing side of the shield, the instrument having an illumination source which emits at the infrared wavelengths to which the shield is transparent.
14. The method of claim 13 wherein the instrument is an eccentric photorefractor.
15. The method of claim 13 wherein the shield is a pair of glasses.
16. The method of claim 13 wherein the shield is a pane of material.
17. The method of claim 13 wherein the shield is a hood.
18. The method of claim 13 comprising displaying a relaxing image to the subject before the step of carrying out the examination.
19. The method of claim 18 wherein the relaxing image is an image introduced into the subject's line of sight to the instrument.
20. The method of claim 11 including a display system for introducing an image into the subject's line of sight to the instrument.
21. The method of claim 11 wherein the instrument is an eccentric photorefractor which includes:
an image source which is not in the line of sight between the subject and the instrument; and
an image display element which is in the line of sight between the subject and the instrument.
22. The method of claim 11 wherein the nontransparency of the shield to visible wavelengths is selectable.