Abstract: An ophthalmic instrument for viewing an eye under examination, wherein the instrument includes image capture means (26) for capturing an image of said eye and data processing means (40, 42, 46) for converting said image into a computer readable file, wherein the instrument carries a memory (44, 200), which may be detachable, for storing said file for subsequent transfer to a computer.

Abstract: A binocular indirect opthalmoscope has a light source for producing an illumination beam and an illumination mirror (7) for directing the illumination beam to an eye to be viewed. The opthalmoscope also has, viewing optics including left-hand and right-hand eyepieces (12,13) and an optical splitter (9,10) for directing light along left-hand and right-hand viewing paths to the two eyepieces. An aperture holder (20) is pivotally mounted in a frame (3,5,6) of the opthalmoscope and adjusts the size of the illumination beam, under the control of a manually rotatable control knob (24). The movement of the aperture holder is transmitted, by means of mechanical linkage, to a moveable carriage (15) on which is mounted both the optical splitter and the illumination mirror, so that when the user moves the control knob to adjust the size of the illumination beam the optical splitter and the illumination mirror are also adjusted in position with respect to the opthalmoscope frame.

Abstract: An ophthalmoscope has illuminating optics (10) for projecting a beam of light into an eye under examination and imaging optics (14) for creating an image of said eye for viewing by a user. The imaging optics comprises an objective lens system (16) and an eye piece lens system (20). Two corneal reflex stops (138 and 148) are positioned one on either side of the corneal image formed by the objective lens system. The stops block reflections from the cornea of the eye under examination over a range of distances of the ophthalmoscope from the eye. The use of the two corneal reflex stops results in the precise positioning of the ophthalmoscope relative to the eye under examination not being critical to the blocking of the corneal reflex.

Abstract: A streak retinoscope projects an elongate patch of light onto the retina of an eye under examination. A housing (1) contains means for rotating the patch relative to the eye and adjustable focusing means for focusing the patch on the eye. Both the rotation means and the focusing means are adjusted by a single control member, such as sleeve (62), which encircles at least part of the housing member. The control member is coupled at least to the rotation means (and preferably also to the focusing means) by a magnetic linkage so as to permit rotation of the control member on the housing through at least one full revolution.

Abstract: An indirect ophthalmoscope is used in the observation of the eye, and comprises viewing optics through which, in use, at least part of said eye is viewed. Light from the eye travels to and through the viewing optics along a viewing path, and the ophthalmoscope includes a lens (36) which is movable between an operative position (in which it is situated in the viewing path) and an inoperative position (in which it is situated clear of the viewing path). The lens 36 can be used to enable the observer to see a magnified image of the eye under examination.

Abstract: A spot retinoscope is used to assess a refractive error of an eye, and has viewing means (11, 12) for viewing the eye under examination, and projection means (6, 9) for directing a beam of light from a light source (5; 82) into said eye thereby to project a spot of light onto the latter. The divergence and convergence of the beam can be altered by focusing means (6, 48) movable from a normal position in which the beam is divergent, or converges to a point (in use) behind the eye under examination, to a cross-checking position, in which the beam is convergent on a point which, in use, is sufficiently far in front of the eye under examination to enable the user to detect movement of the patch of light projected onto the retina of said eye where any refractive error in the eye has not been corrected by a lens placed between the eye and the retinoscope. The retinoscope may also be used (with a further light source) as a streak retinoscope.

Abstract: An ophthalmoscope has viewing optics through which, in use, the user views an eye under examination. Those optics include one or more light receiving elements (62 and 64). The ophthalmoscope also has a centrally positioned camera (14) for detecting an image corresponding to that seen by the user. Light is reflected into the camera objective by means of a reflector (16) which is also centrally positioned on the ophthalmoscope and is situated in substantially the same plane as said elements of the viewing optics, but is laterally spaced therefrom. The central positioning of the camera does not adversely affect the lateral weight distribution of the ophthalmoscope, whilst the provision of a reflector at the same level as the optical elements helps to preserve the congruents between the image detected by the camera and that seen by the user if the condenser lens (used to form the virtual image of the eye under examination) is moved towards or away from the ophthalmoscope.

Abstract: An indirect ophthalmoscope is equipped with a camera (14) to enable the view seen by the user of the ophthalmoscope to be displayed. Light is reflected into the camera by a reflector such as a prism (16) which is preferably substantially co-planar with the ophthalmoscope's optical elements (through which the user sees an eye under examination). The prism (16) and camera (14) are centrally mounted on the ophthalmoscope through mounting means, such as a frame, which has adjustment means for adjusting the positions of the prism and camera relative to the ophthalmoscope so as to alter the position of the field of view of the camera relative to the ophthalmoscope's optical elements. The adjustment means help to ensure that the field of view of the camera, and hence the displayed image, corresponds to the view seen by the user of the ophthalmoscope. The camera, prism and frame may form part of an attachment which may be retrofitted to an existing ophthalmoscope.

Abstract: A tonometer for measuring the intra-ocular pressure of an eye in which a pulse of fluid is projected towards the cornea of the eye to distort the corneal surface by the pressure of the pulse, the distortion in the corneal surface being detected by a change in the reflection of light directed onto the cornea. A constant volume chamber forms part of the fluid delivery system, with an inlet by which fluid under pressure can be supplied to the chamber when a fluid pulse is required. A lens assembly is fixed in the chamber wall for directing light toward an eye under test and a tube extends coaxially through the lens assembly to protrude internally into the chamber, where it is closed off at the end but includes a plurality of apertures in the internally protruding wall section to permit the controlled passage of fluid from the chamber into the tube.

Abstract: A tonometer is described for measuring the intra-ocular pressure of an eye in which a pulse of fluid is projected towards the cornea of the eye to distort the corneal surface by the pressure of the pulse, the distortion in the corneal surface being detected by a change in the reflection of light directed onto the cornea. A fluid delivery system (36, 44, 48) leads to an outlet through which the fluid pulse is applied to the cornea, and a branch (54) leads to a pressure measuring chamber (52), containing a transducer (170) which produces an electrical signal whose value depends on the pressure in the branch. A flow restrictor is removably fitted in the branch (54) and signal processing means (176, 178, 180) (the gain and rise time of which are adjustable by (182) or (186)), is supplied with the output from the transducer. Adjustment of 182, and 186 enable the electrical signal output of the processing means to be adjusted, for calibration.

Abstract: A tonometer which comprises a casing adapted to be hand-held, said casing including an optical system (10 to 26) for forming a viewable image of the cornea of the eye (28), optical detecting means (32, 34A, 34B) for determining when the tonometer, which is by hand slowly moved around, is axially aligned with the cornea, means (40 to 58) for firing a controlled puff of air on to the cornea when a condition of stabilized alignment is determined, and circuitry responsive to the outputs of the optical detecting means for determining when a change in image contrast occurs due to applanation of the cornea, said puff firing means and said circuitry being adapted to measure the pressure at the eye when applanation is detected. The tonometer may take the form of a portable system in which at least some of the components are contained in a hand-held unit (100). Alternatively the tonometer may be bench-mounted.