Method and apparatus for analyzing contaminants in aqueous humor

• US 4,350,163 A
• Filed: 05/29/1980
• Issued: 09/21/1982
• Est. Priority Date: 05/29/1980
• Status: Expired due to Term

• Current Assignee: Coulter Electronics of New England Incorporated
• Original Assignee: David K. Dueker, Norman C. Ford Jr
• Inventors: Ford, Norman C. Jr., Dueker, David K.
• Primary Examiner(s): Michell, Robert W.
• Assistant Examiner(s): Hanley, John C.
• Application Number:
  US06/154,432
• Time in Patent Office: 845 Days
• Field of Search: 128/633, 128/737, 128/745, 128/6, 351/6, 351/16, 351/39, 351/1, 356/340, 356/337, 356/338, 356/339
• US Class Current: 600/318
• CPC Class Codes: A61B 3/10 Objective types, i.e. instruments for examining the eyes independent of the patients' perceptions or reactions
• CPC Class Codes: A61B 3/117 for examining the anterior chamber or the anterior chamber angle, e.g. gonioscopes

Abstract

Method and apparatus are disclosed for measuring contaminants in aqueous humor without rupturing an examined eye. The apparatus includes a laser which projects a light beam through a gonioscopic lens into the aqueous humor of the examined eye. The light is scattered in the humor with a portion of the scattered light being reflected by the gonioscopic lens to an analyzing system. The system measures the diffusion constant of any contaminant in the aqueous humor and, by comparing the diffusion constant to a set of known diffusion constants, determines the composition of the macromolecules or the cells of the contaminant.

Claims

1. An apparatus for measuring contaminants in humor of an eye by non-invasive measurement of the eye, the apparatus comprising:

(a) a continuous wave laser for producing light beams of known wave length;

(b) projection means for directing and converging a light beam from the laser to a focal point in the humor, said projection means including a gonioscopic lens having a transparent housing with an opaque outer surface and an attached concave recess adapted to fit over the cornea of the examined eye, wherein the concave recess is substantially opaque except for a transparent entrance port to admit the laser beam into the humor, a transparent viewing port to permit a clinician to view scattering of the beam in the humor, and a transparent exit port to collect scattered light from the humor; and

(c) means for analyzing the composition of macromolecular contaminants in the humor by analyzing the diffusion constant of each contaminant by using the light scattered from the focal point at a particular scattering angle θ

relative to a line of symmetry for the beam in the humor.

2. The apparatus of claim 1 wherein:

(a) the gonioscopic lens further includes an input mirror for directing the beam into the humor and an output mirror for directing the scattered light to the analyzing means; and

(b) the projection means includes a first optical fiber for directing the beam onto the input mirror and through the entrance port into the humor and a second optical fiber for directing the scattered light from the output mirror to the analyzing means, said fibers having end portions that are respectively received in separate bores of the housing of the gonioscopic lens.

3. The apparatus of claim 2 wherein the projection means further includes adjustment means for selectively adjusting the position of the focal point in the humor.

4. The apparatus of claim 2 wherein said end portion of the first optical fiber is movable within its associated bore of the gonioscopic lens to adjust the position of the focal point in the humor.

5. An apparatus for measuring contaminants in humor of an eye by non-invasive measurement of the eye, the apparatus comprising:

(a) a continuous wave laser for producing light beams of known wave length;

(b) projection means for directing and converging a light beam from the laser to a focal point in the humor;

(c) means for analyzing the composition of macromolecular contaminants in the humor by measuring the diffusion constant of each macromolecular contaminant by using the light scattered from the focal point at a particular scattering angle θ

relative to a line of symmetry for the beam in the aqueous humor;

(d) wherein the projection means comprises a gonioscopic device having;

(i) a housing having an input mirror for directing the beam into the humor;

(ii) said housing having an attached concave recess adapted to fit over the cornea of the examined eye, wherein the recess is substantially opaque except for a plurality of transparent ports, one of said ports being an entrance port to admit the beam relected from the input mirror into the humor, and another of said ports being an exit port to collect scattered light from the humor; and

(iii) said housing having an output mirror for directing the scattered light to the analyzing means.

6. The apparatus of claim 5 wherein the projection means further includes a first optical fiber for directing the beam from said laser onto the input mirror, said fibre having an end portion that is slidably received within said housing for said gonioscopic device and movable therein to adjust the position of the focal point in the humor.

7. The apparatus of claim 6 wherein the projection means further includes a focusing lens between said end portion of said first fiber and said input mirror for focusing the beam to the focal point in the humor, said focusing lens being attached to said housing for said gonioscopic device.

8. A method for analyzing the composition of contaminants in aqueous humor by non-invasive measurement of an examined eye, the method comprising:

(a) directing and focusing a laser beam of known wavelength through a gonioscopic lens to a focal point in the aqueous humor;

(b) collecting light scattered from the focal point at a scattering angle θ

relative to a line of symmetry for the beam in the aqueous humor;

(c) transforming the collected light into electrical pulses;

(d) producing electrical signals representative of the following autocorrelation function G(kΔ

t) for only those pulses above a predetermined amplitude;

##EQU5## where;

Δ

t=a predetermined time interval;

n=the number of pulses during a particular time interval;

i=an indexing number going from 1 to the total number of intervals X the scattered light is collected; and

K=a plurality of successive integers starting with the integer 1;

(e) computing the composition of contaminants in the aqueous humor by using standard curve fitting routines for the following alternative equation for the autocorrelation function G(KΔ

t) to solve for B₁, B₂ . . . B_n and D₁, D₂ . . . D_n ;

space="preserve" listing-type="equation">G(KΔ

t)=A'"'"'+[B.sub.1 e.sup.-D.sbsb.1.sup.C.spsp.2.sup.(KΔ

t) +B.sub.2 e.sup.-D.sbsb.2.sup.C.spsp.2.sup.(KΔ

t) + . . . B.sub.n e.sup.-D.sbsb.n.sup.C.spsp.2.sup.(KΔ

t) ].sup.2

where;

A'"'"'=a constant;

B₁, B₂ . . . B_n =constants each dependent upon the concentration of a particular type of contaminant in the aqueous humor;

D₁, D₂, D_n =diffusion constants for each potential contaminant; and

e=the base of natural logarithms;

wherein known diffusion constants for contaminants are substituted for D₁, D₂ . . . D_n and B₁, B₂ . . . B_n are assigned different values until the values of the alternative equation best approximate the measured electrical signals.

9. The method of claim 8 wherein the contaminants analyzed are macromolecular.

10. The method of claim 8 wherein the contaminants analyzed are cellular.