Handheld device for measuring macular pigment

1. An instrument for determining macular pigment of a macula of an eye of a user, comprising:

a housing including a lower hand-held portion with a user-input button configured for actuation by the user and a display for displaying an MPOD score for the user, the lower hand-held portion further including a battery and electronics for operating the instrument; and

a viewing tube coupled to the hand-held portion and terminating in an eye cup configured to be placed over the eye of the user, the viewing tube being transverse to the lower hand-held portion, the viewing tube including a light source for transmitting light and a blocking wall with an aperture adjacent to the light source, the viewing tube further including a light ring with a center opening, the light ring being located between the blocking wall and the eye cup, the light source is located in the viewing tube such that the light is transmitted through the aperture of the blocking wall, through the center opening of the light ring, and toward the eye cup, the light source providing two colored lights alternating at an initial frequency that is not perceptible by the user, the frequency decreasing from the initial frequency until the user activates the user-input button in response to a frequency at which the user perceives a flicker of the two colored lights, the perceived frequency being used to for determining the MPOD score for the user.

2. The instrument of claim 1 , wherein the aperture of the blocking wall is about 2 mm away from the light source.

3. The instrument of claim 1 , wherein a diameter of the viewing tube is in a range from 20 mm to 35 mm.

4. The instrument of claim 1 , further including a tactile-feedback device or an audio-feedback device that is actuated in response to the user activating the user-input button.

5. The instrument of claim 1 , wherein the two colored lights are a blue light and a green light, the blue light and the green light are generally in opposite on-off phases with some overlap at a transition between the phases.

6. The instrument of claim 5 , wherein the light source is a multi-colored LED.

7. The instrument of claim 1 , wherein the viewing tube includes a slot into which a lens can inserted.

8. The instrument of claim 7 , wherein the lens is selected for the user from a kit of lenses having diopter values between 10-15.

9. The instrument of claim 1 , wherein the viewing tube is generally perpendicular to the lower hand-held portion.

10. The instrument of claim 1 , further including a battery located at a lowermost portion of the lower hand-held portion for providing more stability of the instrument when being held by the user.

11. The instrument of claim 1 , wherein a front surface of the blocking wall facing the eyecup is lighter colored, and a front surface of the light ring facing the eyecup is darker colored.

12. The instrument of claim 1 , wherein a front surface of the blocking wall facing the eyecup is white.

13. The instrument of claim 1 , wherein the light ring emits light of a different color than the two colored lights of the light source.

14. The instrument of claim 13 , wherein the light ring illuminates the blocking wall.

15. The instrument of claim 14 , wherein the light ring emits white light.

16. The instrument of claim 14 , wherein a front surface of the light ring facing the eyecup is darker colored.

17. The instrument of claim 1 , wherein the light source transmits the light directly towards the aperture in the blocking wall.

18. The instrument of claim 17 , wherein the light source is mounted along a center axis of the viewing tube.

19. The instrument of claim 1 , wherein the light source is located at the rear of the viewing tube and spaced away from the blocking wall.

20. The instrument of claim 1 , wherein the light source is mounted on the blocking wall.