fig2 illustrates a first embodiment of device 10 of the present invention . band 12 is attached to device 10 and includes hook and loop fasteners 14 or other suitable means for securing device 10 about the patient &# 39 ; s head . device 10 includes illumination unit 15 and eye piece 16 . eye piece 16 conforms to the patient &# 39 ; s facial contours and creates a substantially light fast seal around the patient &# 39 ; s eye . because facial contours surrounding the eyes of most patients are approximately symmetrical , eye piece 16 , if fitted to one of left and right eyes need merely be rotated 180 ° about axis a to adapt it for use with the other eye . locking ring 20 is provided to secure the position of eye piece 16 once fitted to an eye . alternatively , eye piece 16 may be designed for use with both eyes without rotation , for instance , having a bellows for adjusting to the facial contours surrounding both the left and right eyes of the patient . referring to fig4 and 5 , device 10 includes an array of light sources 58 mounted on unit 15 . because unit 15 is designed to occlude a patient &# 39 ; s eye from ambient light , it includes an opaque wall or backing 22 behind sources 58 . light sources 58 may be leds , lcd pixels , fiber optics , incandescent or fluorescent light - emitting sources , or any other suitable means for providing light at frequencies in the visible spectrum . light sources 58 are distributed within unit 15 so as to span the entire scope of a normal field of vision , i . e ., when device 10 is placed over the subject eye , the distribution of light sources 58 extends to or beyond the limits of peripheral vision of a normal patient . a fixation source 58a is positioned so that it is directly in the center of the patient &# 39 ; s field of vision when the patient is looking straight ahead . regardless of the type of light source used , each source 58 may be independently illuminated . for instance , if leds are used , as shown in fig4 and 5 , each led may be connected to a separate switch and then to a power source . the switches are operated , either manually or by a control unit , to illuminate selectively leds in accordance with a testing sequence . if lcd pixels are used , as in fig6 and 7 , a single illumination source 50 is provided which remains illuminated at all times during the operation of device 10 . lcd array 52 is interposed between the illumination source 50 and the patient &# 39 ; s eye . to &# 34 ; turn on &# 34 ; a pixel , a desired pixel 58b is rendered transparent , allowing light to pass through lcd array 52 at that point . of course , arrays other than that shown in fig4 - 7 may be used in accordance with the present invention as long as they provide sufficient coverage to test the full range of field of vision . device 10 may be self contained , as in fig2 thus including a battery and control circuitry , which may contain an onboard memory for story preprogrammed control sequences . device 10 may also contain either a series of external switches 60 or external lights 62 ( fig2 a ), corresponding to the internal light sources . device 10 can be operated automatically , in response to voice commands or by depressing one or more of external switch 60 in a predetermined pattern to initiate a preprogrammed test sequence . device 10 can also operate manually where the practitioner illuminates each interior light 58 source by pressing a corresponding external switches 60 . referring to fig2 a , sources 62 may be placed on the outer face of device 10 so as to correspond to sources 58 in a one - to - one relationship , providing the practitioner with visible confirmation of the particular source or sources 58 which are illuminated at any given time . of course , any other suitable means for confirming which sources 58 are illuminated may be employed as alternatives to light sources 62 . depending on the type of light sources 58 selected and the functions to be performed by device 10 , additional electric circuitry may be connected to the device 10 as necessary to serve as an interface with other electric or electronic components such as ( but not limited to ) a computer or provide means for the practitioner to monitor the status of each light source 58 during the examination or procedure . referring to fig3 in a second embodiment device 10 is connected to a control unit 80 which has a number of switches 82 . control unit 80 comprises a computer and memory . the computer can selectively control each light source 58 and does so based on a control sequence stored in the memory . multiple control sequences can be stored in the memory , each sequence corresponding to a different test pattern . each switch 82 allows the selection and initiation of a different test pattern . hand switch 84 is provided so that the patient can respond when he or she detects a test signal . control unit 80 may also be connected to a printer 86 so that a record of the test may be produced and place in the patient &# 39 ; s medical file . the printout may include a graphical printout that mimics the distribution of light sources 58 and illustrates which light , when illuminated , did not evoke a response from the patient . to operate device 10 , the practitioner illuminates light source 58a in the center of unit 15 and instructs the patient to direct his or her eye to view source 58a . this centers the eye so that when test signals are delivered , the patient is detecting the test signal with his or her peripheral vision and not by looking towards the test signal . thereafter , other sources 58 are sequentially illuminated in a random pattern . as each source illuminates , the patient , if he or she detects the test signal , responds verbally or by depressing handswitch 84 . the results are recorded manually by the practitioner or electronically by printer 86 . when the embodiment of fig2 is employed , a control sequence stored in an onboard memory of device 10 may be triggered by depressing a predetermined sequence of switches 60 . alternatively , device 10 may be operated manually by depressing switches 60 , thereby illuminating corresponding sources 58 . when the embodiment of fig2 a is employed , external light sources 62 , which correspond to light sources 58 , illuminate in concert with the corresponding internal source 58 . in this manner , the practitioner can observe that an internal light source 58 has been illuminated . thereafter , if the patient does not respond the practitioner can conclude that the patient has failed to detect a test signal and record this result . if the patient is unable to signal verbally or by pressing the handswitch 84 due to some incapacity , the practitioner can instruct the patient to look towards any test signals that he or she detects . once the test signal has disappeared , the patient looks back to the central source 58a . because the eyes are equally enervated , the eyes generally act in coordination . thus , when the patient looks to the test signal , the uncovered eye will follow the movement of the eye being tested . the practitioner , by observing the movement of the uncovered eye , can thus determine whether the patient has detected the test signal . in the case of a small child , a object such as a toy may be held before the child to distract his or her attention and bring the uncovered eye ( and therefore the covered eye , as well ) to a forward , centered position . as the test signal is provided , the child , if he or she detects it , will look thereto . the practitioner can then observe the uncovered eye and note movement towards the location of the test signal . in the conventional means for assessing field of vision , the test surface onto which test signals are projected may be several feet away from the patient . furthermore , the test signals are usually made quite dim to assure the sensitivity of the exam . as a result , someone with imperfect vision may be unable to see the test signal , not due to a lack of peripheral vision , but simply because the image is lost due to the patient &# 39 ; s decreased visual acuity . while decreased visual acuity resulting from myopia may be accommodated with corrective lenses , such lenses may not always be available , as , for instance , in a hospital room . furthermore , some types of visual dysfunction , such as cataracts , limit the distance viewing of a patient and cannot be corrected with lenses . in the present invention , the eye being tested is occluded from ambient light and light sources 58 are very close to the eye . as a result , the retinal image caused by light sources 58 remains blurry and the brain of a patient does not sense the light source 58 as being nearby . thus no convergence , or &# 34 ; awareness of nearness ,&# 34 ; is stimulated . instead , the patient perceives the illumination as being at an infinite distance . the actual nearness of light sources 58 , however , assures that the patient will not fail to detect test signals due to a lack of visual acuity that cannot be corrected for by the testing device , such as cataracts . because light sources 58 are in close proximity to the subject eye , testing anomalies due to lack of visual acuity are reduced or eliminated . furthermore , the apparent infinite distance of the image allows the eye to relax , reducing eye strain and fatigue and increasing the comfort level of the patient . the foregoing is provided for purposes of illustration , explanation , and description of embodiments of the present invention . modifications and adaptations to these embodiments , including interchangeability among the embodiments of various features described herein , will be apparent to those of skill in the art and may be made without departing from the scope or spirit of the invention . the second set of light sources 60 , for example , could be hingedly - mounted to the exterior of eyepiece 16 to permit the practitioner to confirm the illumination status of light sources 58 from varying positions relative to the patient .
an apparatus for performing assessments of field of vision that is portable , does not require the patient to adopt a particular posture or position relative to the testing device and may be operated so as to require minimal active responses from the patient is disclosed . the invention includes a patch , cover , or other device designed to occlude from ambient light and visually stimulate the subject eye . the interior of the patch facing the occluded eye includes an array of light sources , such as leds or lcd pixels , selective and sequential illumination of each source being controlled electrically by the practitioner , either manually or via a computer controller . the close proximity of the light sources to the eye being tested also minimizes anomalous results arising from poor visual acuity .