Ophthalmologic apparatus

• US 9,119,571 B2
• Filed: 01/23/2012
• Issued: 09/01/2015
• Est. Priority Date: 02/04/2011
• Status: Active Grant

• Current Assignee: Tomey Corporation
• Original Assignee: Tomey Corporation
• Inventors: Kato, Chihiro, Nozawa, Yuji, Ohmori, Tsutomu
• Primary Examiner(s): WILKES, ZACHARY W
• Application Number:
  US13/355,974
• Publication Number:
  US 20120200827A1
• Time in Patent Office: 1,317 Days
• Field of Search: 351/206
• US Class Current: 1/1
• CPC Class Codes: A61B 3/1005 for measuring distances inside the eye, e.g. thickness of the cornea A61B3/11 takes precedence
• CPC Class Codes: A61B 3/102 for optical coherence tomography [OCT]
• CPC Class Codes: A61B 3/1173 for examining the eye lens
• CPC Class Codes: A61B 3/12 for looking at the eye fundus, e.g. ophthalmoscopes A61B3/13 takes precedence
• CPC Class Codes: A61B 3/152 for aligning
• CPC Class Codes: G01B 9/02004 using frequency scans
• CPC Class Codes: G01B 9/02062 Active error reduction, i.e. varying with time
• CPC Class Codes: G01B 9/02064 by particular adjustment of coherence gate, i.e. adjusting position of zero path difference in low coherence interferometry
• CPC Class Codes: G01B 9/02068 Auto-alignment of optical elements
• CPC Class Codes: G01B 9/02091 Tomographic interferometers, e.g. based on optical coherence

Abstract

An ophthalmologic apparatus comprises a light source 12, an optical measurement system 13 that radiates first light from the light source to inside an eye to be examined and guides first reflected light from the eye, an optical reference system (24, 22) that radiates second light from the light source to a reference surface and guides second reflected light from the reference surface, a photo detector 26 that detects interfering light between the first reflected light from the optical measurement system and the second reflected light from the optical reference system, and a processor that determines a position of a measuring portion of the inside of the eye based on the detected interfering light. The optical measurement system comprises an incident angle changing member 46 that changes an incident angle of the first light radiated to the eye within a predetermined angular range relative to an axis of vision of the eye.

Claims

1. An ophthalmologic apparatus comprising:

a light source;

an optical measurement system that radiates first light from the light source to inside an eye to be examined and guides first reflected light from the eye;

an optical reference system that radiates second light from the light source to a reference surface and guides second reflected light from the reference surface;

a photo detector that detects interfering light between the first reflected light from the optical measurement system and the second reflected light from the optical reference system; and

a processor that determines a position of a measuring portion inside the eye based on the detected interfering light,

wherein the optical measurement system comprises an incident angle changing member that changes an incident angle of the first light radiated to the eye within a predetermined angular range relative to an axis of vision of the eye,

the incident angle changing member scans the incident angle within the predetermined angular range during a measurement,

the photo detector detects the interfering light of each scan angle and outputs an interference signal of each scan angle to the processor,

the interference signal of each scan angle includes a first signal component and a second signal component, the first signal component being created by the second reflected light and reflected light from a front surface of the measuring portion, and the second signal component being created by the second reflected light and reflected light from a rear surface of the measuring portion,

the processor that determines the position of the measuring portion inside the eye based on the detected interfering light further comprises the processor determining a position of the front surface of the measuring portion based on the first signal component of the interference signal of each scan angle in a depth direction of the eye and the processor determining a position of the rear surface of the measuring portion based on the second signal component of the interference signal of each scan angle in a depth direction of the eye,

the optical measurement system further comprises a focal point adjustment mechanism that changes a focal point of the first light for matching front and rear surfaces of the measuring portion, and an optical path length changing mechanism that changes an optical path length between the light source and the eye,

the focal point adjustment mechanism comprises a first convex lens disposed on a focal aim of the optical measurement system, a second convex lens disposed on the focal aim of the optical measurement system between the first convex lens and the eye, and an actuator that moves the second convex lens relative to the first convex lens in the focal aim direction, and

the optical path length changing mechanism comprises a corner cube disposed on the focal aim of the optical measurement system and an actuator that moves the corner cube in order to change the optical path length between the light source and the eye.

2. The ophthalmologic apparatus as in claim 1, wherein

the focal point adjustment mechanism comprises a convex lens disposed on a focal aim of the optical measurement system, a concave lens disposed on the focal aim of the optical measurement system between the convex lens and the eye, and an actuator that moves the concave lens relative to the convex lens in the focal aim direction.

3. The ophthalmologic apparatus as in claim 1, wherein

the incident angle changing member is a mirror disposed on a focal aim of the optical measurement system, the mirror changing the incident angle and an incident position of the first light, and

the ophthalmologic apparatus further comprises a distance adjustment system that adjusts a distance between the mirror and the eye.

4. The ophthalmologic apparatus as in claim 3, wherein

the mirror is a galvano mirror disposed on a focal aim of the optical measurement system.

5. The ophthalmologic apparatus as in claim 1, wherein the measuring portion comprises at least one from the group consisting of the cornea or the crystalline lens.

6. An ophthalmologic apparatus comprising:

a light source;

an optical measurement system that radiates first light from the light source to inside an eye to be examined and guides first reflected light from the eye;

an optical reference system that radiates second light from the light source to a reference surface and guides second reflected light from the reference surface; and

a photo detector that detects interfering light between the first reflected light from the optical measurement system and the second reflected light from the optical reference system,

wherein the optical measurement system comprises an incident angle changing member that changes an incident angle of the first light radiated to the eye within a predetermined angular range relative to an axis of vision of the eye,

the incident angle changing member scans the incident angle within the predetermined angular range during a measurement,

the photo detector detects the interfering light of each scan angle and outputs an interference signal of each scan angle to a processor,

the interference signal of each scan angle includes a first signal component and a second signal component, the first signal component being created by the second reflected light and reflected light from a front surface of a measuring portion, and the second signal component being created by the second reflected light and reflected light from a rear surface of the measuring portion,

the optical measurement system further comprises a focal point adjustment mechanism that changes a focal point of the first light for matching front and rear surfaces of the measuring portion, and an optical path length changing mechanism that changes an optical path length between the light source and the eye,

the focal point adjustment mechanism comprises a first lens disposed on a focal aim of the optical measurement system, a second lens disposed on the focal aim of the optical measurement system between the first lens and the eye, and an actuator that moves the second lens relative to the first lens in the focal aim direction, and

the optical path length changing mechanism comprises a corner cube disposed on the focal aim of the optical measurement system and an actuator that moves the corner cube in order to change the optical path length between the light source and the eye.

7. The ophthalmologic apparatus as in claim 6, wherein

the focal point adjustment mechanism changes a focal point of the first light from the light source in its focal aim direction.

8. The ophthalmologic apparatus as in claim 7, wherein the first lens comprises a convex lens and the second lens comprises a concave lens.

9. The ophthalmologic apparatus as in claim 7, wherein the first lens comprises a convex lens and the second lens comprises a convex lens.

10. The ophthalmologic apparatus as in claim 6, wherein the measuring portion comprises at least one from the group consisting of the cornea or the crystalline lens.