Diagnosis of A Avitaminosis (Patent No: 394641)

Inventor: Pett, L. Bradley

Location: Edmonton

Comments: chemistry professor at University of Alberta

Description:
Having regard to the foregoing disclosure, the Patent of which this specification forms part confers, subject to the conditions prescribed in the Patent Act, 1935, the exclusive right, privilege and liberty of making, constructing, using and vending to others to be used, the invention as defined in claims submitted by the patentee as follows:-

1. The method of diagnosing A avitaminosis in humans which comprises temporarily impairing the vision of a subject by exposure to bright light, measuring the time required for the subject to regain normal vision, and using said time as an index of the subject's vitamin A supply.

2. The method of diagnosing A avitaminosis in humans which comprises causing the subject to view a first light source of a predetermined intensity for a predetermined time, replacing said light source by a second light source of a predetermined intensity which is less than that of said first source, measuring the time interval between the instant of replacing the first light source and the instant at which the subject first discerns said second light source, and using said time interval as an index of the subject's vitamin A supply.

3. The method of diagnosing A avitaminosis in humans which comprises causing a subject to view an illuminated field of predetermined area and light intensity for a predetermined time, reducing the area and intensity of the illuminated field each by predetermined amounts, measuring the time interval between the instant of said reduction and the instant at which the subject first discern, the reduced field, and using said time interval as an index of the subject's vitamin A supply.

4. The method of diagnosing A avitaminosis in humans which comprises causing a subject to view an illuminated field of predetermined area and light intensity for a predetermined time, substantially instantaneously reducing the intensity of the field by a predetermined amount and reducing the area of the field by a predetermined amount to an outline having an identifying characteristic which can not be anticipated by the subject, measuring the time interval between the instant of said reduction and the instant at which the subject first identifies the outline of said reduced area, and using said time interval as an index of the subjects vitamin A supply.

5. Apparatus for diagnosing A avitaminosis in humans comprising a light source of relatively high intensity, a light source of relatively low intensity, means for energizing said sources alternately, and means for enabling a subject to view the sources in the absence of light extraneous to the apparatus.

6. Apparatus for diagnosing A avitaminosis in humans comprising a relatively large light field, a relatively small light field located centrally of the large field, means for alternately illuminating said fields, and means for enabling a subject to view the fields in the absence of light extraneous to the apparatus.

7. In apparatus as claimed in claim 6, means for adjusting the intensity of each field to a predetermined value.

8. Apparatus for diagnosing A avitaminosis in humans comprising a relatively large light field, means for illuminating the field to a predetermined total intensity which is higher at the margin of the field than at its central portion, a relatively small light field located centrally of said large field, means for illuminating said small field to predetermined intensity alternately with the large field, and means for enabling a subject to view the fields in the absence of light extraneous to the apparatus.

9. In apparatus as claimed in claim 8, means for varying the form in which said small light field appears to the subject.

10. Apparatus for diagnosing A avitaminosis in humans comprising a substantially light tight chamber having a viewing aperture therein, a screen disposed in the chamber with its plane disposed at right, angles to the axis of said aperture, means for illuminating the screen with light of a predetermined intensity, means for alternatively illuminating a portion of the screen with light of a predetermined less intensity, and means for shielding said viewing aperture against light from without the chamber.

11. In apparatus as claimed in claim 10, means for varying the form of said portion of the screen.

12. Apparatus as claimed in claim 10 wherein each of said means for illuminating said screen comprises an electrically energized light source, and wherein voltage controlling and indicating means are provided therefor.

13. Apparatus for diagnosing A avitaminosis in humans comprising a substantially light tight chamber, a viewing tube passing through one wall of the chamber and projecting into the interior thereof, a translucent reflecting screen disposed across the interior of the chamber at right angles to the axis of the viewing tube, an electric light source disposed uniformly around the outside of the viewing tube within the chamber and between the inner end of the tube and the wall of the chamber through which the tube passes, an electric lamp disposed within the chamber on a projection of the viewing tube axis and on the side of the screen remote from the viewing tube, a mask between the screen and said lamp having an aperture therein located approximately on the projected axis of the viewing tube, and switch means for alternately energizing said light source and said lamp or said lamp only.

14. Apparatus as Claimed in claim 15 wherein said mask aperture has an outline the appearance of which, when viewed through the viewing tube, varies with its orientation, and wherein means is provided for varying the orientation of the aperture.

15. In apparatus as claimed in claim 15, a rheostat for controlling the voltage applied to said light source, and a meter for indicating the value of said voltage.