Anamorphic depth gauge for ophthalmic systems
In certain embodiments, an ophthalmic system includes an anamorphic depth gauge (ADG) device and a computer. The ADG device measures the z-location in the interior of an eye and includes a detector array arranged at an oblique angle with respect to the z-axis. The array generates a detector signal in response to detecting a light beam, which has a z-focus in the interior of the eye. A set of line focus optical elements focuses the light beam to form a line focus on the detector array, and a set of nominal focus optical elements focuses the light beam to form a nominal focus on the detector array. The computer: generates an image using the detector signal; determines the position of the nominal focus on the line focus according to the image; and determines the z-location of the z-focus from the position of the nominal focus on the line focus.
1 . An ophthalmic system comprising:
an anamorphic depth gauge (ADG) device configured to measure a z-location in an interior of an eye, the eye having an eye axis that defines a z-axis, the ADG device comprising:
a detector array arranged at an oblique angle with respect to the z-axis, the detector array configured to generate a detector signal in response to detecting a light beam, the light beam having a z-focus in the interior of the eye;
a set of line focus optical elements configured to focus the light beam to form a line focus on the detector array; and
a set of nominal focus optical elements configured to focus the light beam to form a nominal focus on the detector array; and
a computer configured to:
generate an image using the detector signal;
determine a position of the nominal focus on the line focus according to the image; and
determine the z-location of the z-focus from the position of the nominal focus on the line focus.
2 . The ophthalmic system of claim 1 , the oblique angle ranging from 3 to 60 degrees.
3 . The ophthalmic system of claim 1 , a change in the position of the nominal focus proportional to a change in the z-location of the z-focus.
4 . The ophthalmic system of claim 1 :
the image comprising an oblong shape representing the line focus; and
the nominal focus corresponding to a narrowest part of the oblong shape.
5 . The ophthalmic system of claim 4 :
a first z-location of the z-focus corresponding to a first position of the nominal focus; and
a second z-location of the z-focus corresponding to a second position of the nominal focus, the first z-location of the z-focus different from the second z-location of the z-focus, and the first position of the nominal focus different from the second position of the nominal focus.
6 . The ophthalmic system of claim 4 , an optimal z-focus corresponding to the narrowest part centered on the oblong shape.
7 . The ophthalmic system of claim 1 :
the set of line focus optical elements comprise a cylindrical lens and a spherical lens; and
the set of nominal focus optical elements comprise a fan out lens and the spherical lens.
8 . The ophthalmic system of claim 1 :
the set of line focus optical elements comprise a toric lens and a focusing lens; and
the set of line nominal focus optical elements comprise a collimating lens and the focusing lens.
9 . The ophthalmic system of claim 1 , the z-focus located at a target.
10 . The ophthalmic system of claim 9 , the computer configured to determine a z-location of the target according to the z-location of the z-focus.
11 . The ophthalmic system of claim 9 :
further comprising a laser device configured to generate a laser beam; and
the computer configured to instruct the laser device to direct the laser beam at the z-location of the z-focus in order to direct the laser beam at the target.
12 . The ophthalmic system of claim 9 , the z-axis defining an xy-plane orthogonal to the z-axis, further comprising an SLO device configured to determine an xy-location of the target from an SLO image.
13 . The ophthalmic system of claim 1 , the computer configured to:
determine from the z-location of the z-focus whether the z-focus is an optimal z-focus; and
if the z-focus is not the optimal z-focus, adjust the z-focus until the z-focus is the optimal z-focus.
14 . The ophthalmic system of claim 13 , the computer configured to:
determine whether the z-focus is the optimal z-focus by determining whether the image shows an oblong shape with a narrowest part centered on the oblong shape; and
adjust the z-focus until the z-focus is the optimal z-focus by adjusting the z-focus until the image shows the oblong shape with the narrowest part centered on the oblong shape.
15 . The ophthalmic system of claim 1 , the z-axis defining an xy-plane orthogonal to the z-axis, the computer configured to:
perform the following for a plurality of iterations to yield a plurality of xy-plane images of the interior of the eye:
adjust the z-location of the z-focus;
capture an xy-plane image of the interior of the eye at the z-location of the z-focus; and
combine the plurality of xy-plane images to yield a three-dimensional image of the interior of the eye.
16 . An ophthalmic surgical system comprising:
a scanning laser ophthalmoscope (SLO)-anamorphic depth gauge (ADG) system configured to direct an imaging beam towards a target in an eye, the eye having an eye axis that defines a z-axis, the z-axis defining an xy-plane orthogonal to the z-axis, the SLO-ADG system configured to determine an xyz-location of the target, the SLO-ADG system comprising:
an SLO device configured to:
detect the imaging beam reflected by the eye;
generate an SLO image of the target in the eye; and
determine an xy-location of the target from the SLO image;
an ADG device configured to:
detect the imaging beam reflected by the eye; and
determine a z-location of the target;
a laser device configured to direct a laser beam at the xyz-location of the target; and
a computer configured to instruct the laser device to direct the laser beam at the xyz-location of the target.
17 . The ophthalmic surgical system of claim 16 :
the ADG device comprising:
a detector array arranged at an oblique angle with respect to the z-axis, the detector array configured to generate a detector signal in response to detecting a light beam, the light beam having a z-focus in the interior of the eye;
a set of line focus optical elements configured to focus the light beam to form a line focus on the detector array; and
a set of nominal focus optical elements configured to focus the light beam to form a nominal focus on the detector array; and
the computer configured to:
generate an image using the detector signal;
determine a position of the nominal focus on the line focus according to the image; and
determine the z-location of the z-focus from the position of the nominal focus on the line focus.
18 . The ophthalmic system of claim 17 , the computer configured to determine a z-location of the target according to the z-location of the z-focus.
19 . The ophthalmic system of claim 17 , a change in the position of the nominal focus proportional to a change in the z-location of the z-focus.
20 . The ophthalmic system of claim 17 :
the image comprising an oblong shape representing the line focus; and
the nominal focus corresponding to a narrowest part of the oblong shape.
21 . The ophthalmic surgical system of claim 16 , further comprising an xy-scanner configured to:
receive the imaging beam from the SLO-ADG system and direct the imaging beam along an imaging beam path towards the xy-location of the target; and
receive the laser beam from the laser device and direct the laser beam along a laser beam path aligned with the imaging beam path towards the xy-location of the target.