Transactions from the Xth International Orthoptics Congress 2004

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A Clinical Quantitative Measurement Of Ocular Dominance Tomoya Handa a , Hiroshi Uozato a , Kazuo Mukuno a , Takahiro Niida b Nobuyuki Shoji a , Risako Higa c , Marie Nitta c , Kimiya Shimizu c a Department of Orthoptics and Visual Science, School Allied Health Sciences, Kitasato University, 1-15-1 Kitasato, Sagamihara, Kanagawa, 228-8555 Japan. b Department of Orthoptics and Visual Science, School of Health Science, International University of Health and Welfare, 2600-1 Kitakanemaru, Ohtawara ,Tochigi, 324-8501 Japan c Department of Ophthalmology, School of Medicine, Kitasato University, 1-15-1 Kitasato, Sagamihara, Kanagawa, 228-8555 Japan. thanda@kitasato-u.ac.jp Abstract Clinical usefulness of a quantitative measurement of ocular dominance was investigated in normal subjects and in monovision patients. The magnitude of ocular dominance was measured using our balance technique based on binocular rivalry. In the magnitude of ocular dominance, normal subjects showed the large individual variation and unsuccessful monovision patients were significantly higher than successful monovision patients. Our balance technique showed the large individual variation seen in the magnitude of ocular dominance and success and the great influence in success and patient satisfaction in monovision. Keywords Ocular dominance, Binocular rivalry, Sensory eye dominance, Balance technique, Monovision Introduction Clinically, ocular dominance which is judged by a hole-in-card test is the most facile investigative tool for sighting ocular dominance. However, this test is unable to quantitatively assess the magnitude of ocular dominance. Therefore, most clinicians are unable to evaluate the effects of ocular dominance in visual function, especially, evaluating patients having bilateral cataract surgery who opt for monovision. Monovision is an optical means of correcting presbyopia, where dominant eye is corrected for distance and nondominant eye for near. Recently, we developed a balance technique to quantitatively evaluate the quality of ocular dominance. 1, 2 In present study, a clinical usefulness of our balance technique based on binocular rivalry was investigated in normal subjects and monovision patients. Material and Methods The quantity of ocular dominance (sensory dominance) measured in 20 normal subjects, and 16 successful and 4 unsuccessful monovision patients induced by implanted intraocular lenses, using our balance technique 1, 2 (see below for details) based on binocular rivalry. The dominant eye was determined using the hole-in-card test (sighting dominance). Our balance technique 1, 2 : subjects and patients were presented with binocular rivalry targets, i.e., rightward tilted (45º) and leftward tilted (135º) shaped patches of rectangular 2 c/deg gratings that were 4 deg in size. The contrast of the target in the dominant eye was 1
varied, from 100% to 80% to 60% to 40% to 20%, while that in the nondominant eye was fixed at 100% in all trials. Subjects estimated the exclusive visibility as a general dominance of trial target visibility when compared with that of another targets. For the dominant eye trials, subjects were told to press the button when the dominant eye target was exclusively visibility during the dominant eye target was varied from 100% to 80% to 60% to 40% to 20%. For the nondominant eye trials, patients were told to press the button when the nondominant eye target was exclusively visibility during the nondominant eye target was fixed at 100%. Each trial lasted 1 min and was followed by an inter-trial interval of 1 min. All trials were repeated 2 times. The qualities of ocular dominance were quantitatively evaluated as reversal point where exclusive visibility of the nondominant eye crosses over that of the dominant eye. Weak ocular dominance is defined as the reversal points (where exclusive visibility of the nondominant eye crosses over that of the dominant eye) were obtained in low decreasing contrast of 80% and 60% in the dominant eye target. In contrast, strong ocular dominance is defined as the reversal points were observed at high decreasing contrast of 40% and 20% or not at all in the dominant eye. Results The sighting dominant eye identified by hole-in-card test coincided the sensory dominant eye as determined by binocular rivalry. All subjects and patients recognized binocular rivalry regardless of varying contrast in dominant eye. Fig.1 show the reversal point (exclusive visibility of the nondominant eye crosses over that of the dominant eye) in normal subject and monovision patients. The 15 normal subjects showed reversal point at 80% and 60%; the other 5 subjects showed reversal point at 40% and 20%. Reversal point 80% and 60% are weak magnitude comparison with 40% and 20%. In monovision patients, the reversal points (20% and not at all) in unsuccessful patients were a significant lower contrast than that (80% and 60%) in successful patients (p
Page 1 and 2: ‘Global Perspectives Converge Dow
Page 9 and 10: The Burian Memorial Lecture: Factor
Page 11 and 12: Results Seventy-four patients fulfi
Page 13 and 14: three years of surgical alignment,
Page 15 and 16: onto temporal retina, regardless of
Page 17 and 18: Range of accommodation and binocula
Page 19 and 20: Table 2 Patient Preoperative fusion
Page 21 and 22: Assessing The Dominant Eye: A New M
Page 23 and 24: Figure 1. The Sensory Dominance Tes
Page 25 and 26: Does Dissociation Reduce Stereoacui
Page 27 and 28: Methods Observers were students in
Page 29 and 30: Initial 1.2 ** 1.4 ** 6.4 **** 7.1
Page 31 and 32: Does stereoacuity correlate with in
Page 33 and 34: Results The distance and near stere
Page 35 and 36: 3. Frisby, J.P., Davis, H., Edgar,
Page 37 and 38: measurement of sensory dominance (3
Page 39 and 40: Fig. 1. Durations of exclusive perc
Page 41: The results of all four stereotests
Page 45 and 46: Can stereo tests be an indicator of
Page 47 and 48: Pass No. Table 1. Number .of subjec
Page 49 and 50: Stereoacuity Following Unilateral A
Page 51 and 52: Table 1 Pre-operatively Post-operat
Page 53 and 54: Measurement And Improvement Of Visu
Page 55 and 56: Table 1 Criteria for visual skills
Page 57 and 58: Diagnosis And Treatment In Patients
Page 59 and 60: Reduction of asthenopic symptoms -
Page 61 and 62: Monovision By Implanted Intraocular
Page 63 and 64: Acknowledgements This study was sup
Page 65 and 66: The Effect Of Simulated Torsional D
Page 67 and 68: Table 3. Mean fusional convergence
Page 69 and 70: Strabismus In Childhood: Unilateral
Page 71 and 72: 12 cases present documented NRCC, 8
Page 73 and 74: The Use Of A Computerised System Fo
Page 75 and 76: test. The main program also monitor
Page 77 and 78: Abstract Disruption of Binocular Vi

Transactions from the Xth International Orthoptics Congress 2004

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