![]() ![]() ![]() The suppression scotoma in the strabismic patient is largerthan the macular scotoma in the monofixation syndrome patient. Its scotoma is displacedaway from the macula in the nonfixating eye's extramacularretina locus that receives the image projected onto the fixating eye'smacula. Whatever the cause of the macular scotomain the monofixation syndrome patient-dissimilarity of macular imagesexceeding the threshold tolerated for macular fusion, an inherentinability to develop macular binocular vision (bifixation) despite havingdeveloped extramacular binocular vision, or a unilateral maculardestructive disorder-it is not a scotoma generated by a corticalprocess to eliminate symptoms of diplopia and visual confusion, as encounteredin strabismus. The test result merely identifiesthe presence of the macular scotoma in the nonfixating eye of the monofixationsyndrome patient. When this occurs, theexaminer is inclined to state or to record this response as “suppression,” whichit is not. Fusion responseis lost by moving the flashlight away from the patient fartherthan 0.66 meters, and the patient sees either only two red or three greendots, according to which is the fixating eye. On advancing the target towardthe patient, fusion is usually manifest at about 0.66 meters. Because the standard near Worth-dotflashlight projects 6° images at 0.33 meters, the test shouldbegin about 2 meters from the patient. By advancing toward the target, fusionis achieved at about 2.5 meters. If the distant Worth dot test is 6 metersfrom the patient, it is not fused. 2), which precludes a fusion response unless the projection size of thetarget image exceeds 3°. Monofixation syndrome patients have a 3° macular scotoma in the nonfixatingeye ( Fig. The subject should be testedwith the optimal optical correction on (spectacles or contact lenses) behindthe anaglyphic filters.įig. The projection angle of the image is the imaginary circumference encirclingthe outer border of the four dots collectively, not simply theprojection angle of each of the four dots. At 6 meters, the distant Worth dots projectan image of 1.25° at 0.33 meters, the near Worth dots project a 6° angle ( Fig. The latter can be accomplished with the fixed locationof the distant Worth dot test by having the subject advance toward orrecede from the target. The other method is a nearWorth dot test, which consists of a flashlight easily advanced or recededfrom the subject to alter the projection angle of the target imageon the retinas. This isreferred to as the distant Worth dot test. ![]() One is tohave a fixed target at a distance from the subject, which may eitherbe contained in an illuminated box or projected on a screen. ![]() Apatient devoid of macular binocular vision but who possesses extramacularnormal binocular vision does not manifest fusion of the target (subtendingan angle of about 3° or less) yet manifests a fusionresponse for larger targets.Įssentially, two methods of performing the test are available. A normal subject possessing both macularand extramacular binocular vision perceives four dots, regardlesshow minute the projection angle that the target subtends on the retina. The examiner must consider that the response of the patient may vary accordingto the size of the projection angle that the cluster of the fourdots presents to the retinas. If the dominancepattern vacillates between the eyes, the white dot manifests colorrivalry by changing from red to green. Binocularly, however, the fusing subject perceivesthe target as four dots because the white dot is seen as either a singlered or green dot, according to which eye is dominant. The test subject monocularlysees two red dots through the red filter and three green dots throughthe green filter. Thewhite dot is seen as red when viewed through the red filter and asgreen when viewed through the green filter. Viewed through the red filter, the green dots are invisible viewedthrough the green filter, the red dot is invisible. Thepatient views the target through anaglyphic testing glasses thatconsist of a red filter in front of one eye and a green filter in frontof the other. The testingtarget consists of four illuminated dots that are clustered equidistantfrom each other two dots are green, one is red, and one is white. One of the simpler methods for investigating fusion, suppression, and anomalousretinal correspondence (ARC) is the Worth 4-dot test. Diagnosis of the binocular vision adaptations in strabismusis accomplished by observing the results of various tests presentedto the patient. TREATMENT OF BINOCULAR VISION ADAPTATIONSīefore treatment of the sensory status in a strabismic patient, it mustbe diagnosed. Sensory Tests and Treatment of Binocular Vision Adaptations Sensory Tests and Treatment of Binocular Vision Chapter 9 ![]()
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