PURPOSE: We investigated the effects of dominant eye and contextual background on predominance during binocular rivalry. METHODS: 10 subjects were recruited for the present study. Dominant eye was determined using the hole-in-the-card test. In experiment 1, subjects viewed the stimuli through anaglyph filters and reported the predominance of color. The subject's responses were compared with the color on the dominant eye. To investigate the influence of color dominance and contextual color, we conducted the experiment with added contextual color information target through switched-anaglyph filters. In experiment 2, the subject viewed the stimuli through the polarized filters and reported the predominance of orientation. The subject's responses were compared with the grating on dominant eye. To rule out the effect of stimulus size, we conducted the experiment with a smaller target. We designed the additional experiment to investigate the influence of contextual grating information on binocular rivalry. RESULTS: 10 subjects were evaluated. In experiment 1, 8 of 10 subjects reported that eye preference was highly correlated with dominant eye. This finding is significant without reference to color. In experiment 2, 7 of 10 subjects reported that eye preference was highly correlated with dominant eye. This finding is significant without reference to size. In experiment 1-2 and 2-2, all subjects reported that predominance of context contradictory target increased. CONCLUSIONS: We found the relationship between the dominant eye and eye preference. Experiment 1-2 and 2-2 showed that contradictory contextual information increases target predominance during binocular rivalry. Overall, our results indicate that the contextual background reduce the stimulus strength of the context-congruent target; it would correspond to an increase in the dominance duration of the context-contradictory target.
Telescopes*

we investigated the effect of spherical lens-induced anisometropia on dynamic stereoacuity. Twenty subjects with normal binocular function without past ophthalmic disease history were examined for the effect of anisometropia on the viasual acuity, static and dynamic stereoacuity created with spherical lenses in 0.5D stepwise manner before dominant eye from -2.0D to +2.0D. Dynamic stereoacuity was measured by new computer program. And we investigated the effect of anisometropia on dynamic stereoacuity as the power of the lenses was increased and the effect of plus lens vs minus lens on the dynamic stereoacuity. As a result, dynamic stereoacuity decreased statistically significantly as the power of the spherical lenses increased. And the plus 1.5D and 2.0D lens showed more deteriorating effects on dynamic stereoacuity than the corresponding minus power lenses, respectively. No statistically significant correlation was found between static and dynamic stereoacuity at each spherical lens diopter.
Anisometropia* ; Telescopes

A rare case of binocular polycoria due to extensive persistence of the pupillary. membrane was reported. Central visions of both eyes in this case were not disturbed because of the presentation of few holes in the thick pupillary membranes.
Membranes* ; Telescopes*

The near point of accommodation of 500 normal Koreans aged 8 to 70 was measured for the monocular and binocular states. Push-up method with Slataper's one-two line card was used. Calculation for the near:point was measured by Prince rule with AD phoropter. The results were divided into 15 age groups as follows; 1. The age group of 8 to 11 ; The range:of monocular accommodative power was 17.2D. to 12.3D. The mean value was 15.2D. The range of binocular accommodative power was 19.2D. to 14.2D. The mean value was 17.4D. The excess of binocular accommodative power was 2.2D. 2. The age group of 12 to 15 ; The range of monocular accommodative power was 15.2D. to 10.4D. The mean value was 13.8D. The range of binocular accommodative power was 18.8D. to 13.9D. The mean value was 15.4D. The excess of binocular accommodative power was 1.6D. 3. The age group of 16 to 19 ; The range of monocular acocmmodative power was 14.8D. to 9.8D. The mean value was 12.3D. The range of binocular accommodative power was 17.6D. to 12.4D. The mean value was 13.7D. The eXcess of binocular accommodative power was 1.4D. 4. The age group of 20 to 23 ; The range of monocular accommodative power was 13.4D. to 8.8D. The mean value was 11.2D. The range of binocular accommodative power was 15.9D. to 10.8D. The mean value was 12.6D. The excess of binocular accommodative power was 1.4D. 5. The age group of 24 to 27 ; The range of monocular accommodative power was 12.8D. to 8.0D. The mean value was 10.4D. The range of binocular accommodative power was 13.7D. to 9.2D. The mean value was 11.8D. The excess of binocular accommodative power was 1.4D. 6. The age group of 28 to 31 ; The range of monocular accommodative power was 12.0D. to 7.4D. The mean value was 9.5D. The range of binocular accommodative power was 12.8D. to 8.6D. The mean value was 10.8D. The excess of binocular accommodative power was 1.3D. 7. The age group of 32 to 35 ; The range of monocular accommodative power was 11.4D. to 6.6D. The mean value was 8.8D. The range of binocular accommodative power was 11.9D. to 7.9D. The mean value was 10.0D. The excess of binocular accommodative power was 1.2D. 8. The age group of 36 to 39 ; The range of monocular accommodative power was 10.2D. to 5.3D. The mean value was 7.2D. The range of binocular accommodative power was 11.2D. to 6.8D. The mean value was 8.4D. The excess of binocular accommodative power was 1.2D. 9. The age group of 40 to 43 ; The range of monocular accommodative power was 8.2D. to 3.8D. The mean value was 5.4D. The range of binocular accommodative power was 9.7D. to 5.0D. The mean value was 6.4D. The excess of binocular accommodative power was 1.0D. 10. The age group of 44 to 47 ; The range of monocular accommodative power was 7.8D. to 2.3D. The mean value was 4.1D. The range of binocular accommodative power was 9.1D. to 3.4D. The mean value was 4.9D. The excess of binocular accommodative power was 0.8D. 11. The age group of 48 to 51 ; The range of monocular accommodative power was 4.0D. to 1.2D. The mean value was 2.0D. The range of binocular accommodative power was 6.2D. to 1.6D. The mean value was 2.8D. The excess of binocular accommodative power was 0.8D. 12. The age group of 52 to 55 ; The range of monocular accmmodative power was 2.7D. to 0.9D. The mean value was 1.8D. The ranie of binocular accommodative power was 4.3D. to 1.0D. The mean valae was 2.0D. The excess of binocular accommodative power was 0.5D. 13. The age group of 56 to 59 ; The range of monocular accomIllodative power was 1.8D. to 0.7D. The mean value was 1.0D. The range of binocular accommodative power was 2.8D. to 0.7D. The mean value was 1.5D. The excess of binocular accommodative power was 0.5D. 14. The age group of 60 to 63 ; The range of monocular accommodative power was 1.2D. to 0.4D. The mean value was 0.7D. The range of binocular accommodative power was 1.8D. to 0.5D. The mean value was 1.0D. The excess of binocular accommodative power was 0.3D. 15. The age group of 64 to 70 ; The range of monocular accommodative power was 1.0D. to 0.2D. The mean value was 0.6D. The range of binocular accommodative power was 1.6D. to 0.4D. The mean value was 0.8D. The excess of binocular accommodative power was 0.2D. The human ocular occommodative power was decreased according to the increasing age. The binocular accommodative power was larger than the monocular accommodative power. The excess between binocular and monocular accommodative power was also decreased according to the increasing age. In all age group, the mean excess between binocular and monocular accommodative power was about 1.0 diopter that was more or less larger than the Duane's. In the age group of 50 years below, these values were larger than the Duane's. In the age group of 50 years above, these values were similar to the Duane's.
Humans ; Telescopes

PURPOSE: To study the effect of spherical lens induced aniseikonia on stereopsis and fusion. METHODS: One hundred subjects, with normal binocular function without any ophthalmic disease or surgery history, were examined. The aniseikonia was induced with spherical lenses in 1 diopter (D) stepwise manner from -2 D to +2 D. The amount of aniseikonia was measured by Awaya's New Aniseikonia Test. Stereopsis and fusion were determined with Titmus Stereo Test and fusion card of major amblyoscope respectively. RESULTS: As the amount of aniseikonia was increased, the stereopsis and fusion were decreased. The change was statistically significant (ANOVA, p<0.001). Aniseikonia was more correlated to fusion than stereopsis. A significant decline in the stereopsis was detected when the size of aniseikonia changed from 1% to 2%. A significant decline in fusion was noticed when aniseikonia changed from 2% to 3% (Independent t-test, p<0.01). CONCLUSIONS: Our study suggests that binocular function can be disturbed by experimentally induced aniseikonia in normal subjects and that stereoacuities and fusional amplitude can be decreased as the degree of aniseikonia becomes larger.
Aniseikonia* ; Depth Perception ; Telescopes*

Polycoria is a rare congenital anomaly of iris. In a wider sense polycoria is including iris dehiscence and iris diastasis as well as true polycoria. A case of binocular iris dehiscence accompanied with congenital anomalies of teeth was reported and literatures were reviewed.
Iris ; Telescopes* ; Tooth

PURPOSE: The purpose of this study was to evaluate and compare the binocular function in patients with basic and simulated divergence excess types of intermittent exotropia [X(T)]. METHODS: Seventy-seven patients, 46 basic type and 31 simulated divergence excess type, were studied by Worth 4-dot test (W4D), Polarized 4-dot test (P4D), Titmus test, and distance stereoacuity test using Mentor B-VAT(R)II videoacuity tester. RESULTS: Near W4D, distant W4D and distant P4D were fused in 71.7%, 8.6% and 52.2% in basic type and in 100%, 25.8% and 87.1% in simulated divergence excess type, respectively. The fusion rate in simulated divergence excess type was significantly higher, than in basic type (P=0.001, 0.04, 0.001). However, the difference in near P4D between the two types was not significant (P=0.24). In distance stereoacuity test, basic type showed 272 seconds and simulated divergence excess type showed 177 seconds, showing a significant difference (P=0.02). There was no significant difference in near stereoacuity between the two types (P=0.08). CONCLUSIONS: The study demonstrated a difference in binocular function in patients with basic and simulated divergence excess types of X(T). A better binocular function was observed in the latter group.
Exotropia* ; Humans ; Mentors ; Telescopes*

Sixteen normal subjects were tested with the Titmus stereotest varying the binocular Snellen's visual acuity from 1.0 to 0.2. From 15 possible combinations, a nomogram describing the relationship of binocular variations of Snellen's visual acuity and stereoacuity was constructed and the relationship of binocular isoacuities to Titmus stereotest performance was expressed as an S-shaped function.
Nomograms ; Telescopes ; Visual Acuity*

Cyclic heterotropia represents an interesting ocular motility problem in which the ocular deviation is present on a rhythmic basis. Usually this appears in a regular 48-hour cycle, although 72-and 96-hour cycles have also been reported. On the strabismic day, constant heterotropia is large and associated with suppression and no diplopia. On the nonstrabismic day, no deviation or only a small heterophoria is present with good binocular function. In this paper, we present two cases of cyclic esotropia which demonstrated regular 48-hour cycles and were treated with surgery.
Diplopia ; Esotropia* ; Telescopes

PURPOSE: It is known that fusion is promoted in the presence of a peripheral fusion clue in patients with intermittent exotropia, X(T). Therefore, this study compared the results of the Worth 4-dot test (W4D) with the room lights on and off in order to determine the status of the binocular function. METHODS: The W4D test was performed with lights on and off, and the polarized 4-dot test (P4D) was administered in 52 X(T) patients. RESULTS: Among these 3 tests, the fusion rate was the lowest with distance in the W4D with the lights off at 9.6%, which was followed by the W4D with the lights on at 26.9% and the P4D at 57.7%. The fusion rate of the W4D with the lights on in the patients with a distance stereoacuity better than 120 seconds of arc (") was 50%, which was significantly higher than the 18.4% observed in the patients with a stereoacuity at 120" or worse (P=0.023). Among the 14 patients who showed fusion with the distance W4D with the lights on, 10 could not fused with the W4D with the lights off. Therefore, a weak motor fusion was observed in 71.4 % of these 14 patients. CONCLUSIONS: It is possible to verify the more natural condition of the binocular sensory function of patients with X(T) using either the P4D or the W4D with the lights on rather than with the lights off. Furthermore, the W4D test with the lights on can be performed together with and be compared with that conducted with the lights off, for a better understand of the degree of motor fusion.
Exotropia ; Humans ; Sensation ; Telescopes