• Journal of Korean Ophthalmic Optics Society
• /
• v.20 no.4
• /
• pp.511-518
• /
• 2015

Purpose: The purpose of this study is to evaluate correlation between convergence insufficiency and concentration by evaluating attentiveness in children who have convergence insufficiency symptoms. Methods: The CISS survey and examination for the near point of convergence were conducted to 74 in children aged 12 to 13 years in order to divide them into a normal binocular vision (NBV) and a convergence insufficiency (CI) group. The attentiveness examination was used to all subjects to figure out their emotional problems, hyperactivity and impulsiveness problems, and managerial or functional problems with a 5-point scale. Correlation between convergence insufficiency-related symptoms included in CISS and attentiveness problems was analyzed. Results: there were 29 children (39.2%) in the CI group, the mean scores of CISS of the NBV and CI group were $5.91{\pm}3.69$ and $18.31{\pm}7.00$ each (p<0.001). On the survey of CISS symptoms, children in the CI group frequently expressed such symptoms as eye fatigue, loss of attentiveness, blurry vision, and forgetting the line they have been reading. In the attentiveness examination, the CI group ($74.83{\pm}9.83$) gained higher scores in problematic concentration than the NBV group ($46.80{\pm}11.30$). Convergence insufficiency had significantly positive correlation with total attentiveness (r=0.798). Conclusions: In elementary school students, it has been found that when perceived symptoms related with convergence insufficiency are more serious, problematic attentiveness gets serious, too.

• Journal of Korean Ophthalmic Optics Society
• /
• v.16 no.2
• /
• pp.171-177
• /
• 2011

Purpose: The purpose of this study was to investigate the relationships between reading ability and binocular functions, based on self tests through surveys. The possibility of the reading ability tests used in this study as a tool on the determination about vision efficiency was also evaluated. Methods: Through reading ability tests about 138 university students, 72 students (52.2%) of them were first selected. Through self tests about dyslexia and light sensitivity, 38 students (52.7%) of the first selected students were secondly selected, whose extents are more than 3. Binocular tests were carried out about three groups (high, middle, low) of these secondly selected students. Tests about NPCs, distance and near phoria, amplitude of accommodation, fusional vergence, AC/A ratio, accommodative facility, and vergence facility were performed as binocular tests. Results: NPCs were closest to eyes at high groups. Fusional vergence, AC/A ratio, accommodative facility, and vergence facility of high group showed higher than other groups. The phoria at middle group showed higher than other groups. Conclusions: We found that reading ability and some of binocular functions were closely related. Therefore, vision training, associated with insufficiencies of binocular functions, is expected to improve reading ability.

• Journal of Korean Ophthalmic Optics Society
• /
• v.20 no.2
• /
• pp.195-200
• /
• 2015

Purpose: This study was performed in order to figure out the influence of illumination on visual function. Methods: 40 adults (male 21, female 19) of average age $23.93{\pm}1.59$ years were participated in this study. The test chart surface illumination was adjusted to 5, 50, 200, 500 and 800 lx, and then amplitude of accommodation, near point of convergence, far and near distance phoria, far and near distance fusional vergence, relative accommodation, and accommodation lag were measured at each illumination condition. Results: As illumination intensity of test chart was reduced, amplitude of accommodation was significantly decreased (p<0.05), accommodation lag was also decreased, near point of convergence was receded, and horizontal phoria showed a tendency of esodeviation. In the case of negative fusional vergence, with reduction of illumination intensity, the break point and the recovery point were decreased but in the case of positive fusional vergence, the break point was increased. The negative and positive relative accommodation were significantly decreased (p<0.05) with reduction of illumination intensity. Conclusions: In clinical practice, visual functional test should be performed under condition of adequate illumination level through patient's living environment and job.

• Journal of Korean Ophthalmic Optics Society
• /
• v.15 no.1
• /
• pp.105-116
• /
• 2010

Purpose: To analyze and compare differences between single vision lenses and functional progressive addition lenses and improvement to binocular visual function wearing functional lenses for pre-presbyopes altered their single vision lenses to functional progressive addition lenses with low addition. Methods: Healthy 32 subjects aged 24.03${\pm}$1.87 (male 23, female 9) who were recruited from university students wore functional progressive addition lenses (EYE-T, Chemilens Co., Korea, ADD 0.750) for 2 months. Objective refraction, corrected visual acuity at distance and near, near point of convergence, near point of accommodation, accommodative facility, phoria at distance and near were measured. And subjective satisfaction was investigated by using a questionnaire designed to fatigue, comfort, discomfort, overall satisfaction and preference. Results: Functional progressive addition lenses were better than single vision lenses at near point of convergence and accommodation, accommodative facility. Exo phoria measured at distance with single vision and functional progressive addition lenses. Exo phoria measured at near with functional progressive addition lenses was higher than that with single vision lenses. As a survey, the satisfaction was increased in questions related near work. However, single vision lenses were preferred in distance test of overall satisfaction, easy 10 adapt, lime to adapt. A survey showed thai preference of functional progressive addition lenses were increased 75.00% to 81.26% for near work, 50.00% to 65.63% for visual fatigue, 47.75% to 50.00% for visual comfort and 31.25% to 46.88% for overall comfort. Conclusions: Comparing between single vision lenses and functional progressive addition lenses, binocular visual function related near work, subjective satisfaction and preference was improved after wearing functional progressive addition lenses. This study suggested that functional progressive addition lenses were useful for long time near work.

• Journal of the Korea Convergence Society
• /
• v.13 no.2
• /
• pp.55-65
• /
• 2022

The purpose of this paper was to investigate the relationship between cybersickness symptoms and visual function and to determine whether visual perception training is effective in reducing symptoms of cybersickness. The study subjects were healthy adult males who experienced the same virtual reality program for 15 minutes. Afterwards, the VR satisfaction score and cybersickness level were measured and classified into a comfortable virtual reality program viewer group (CVR group, 20 people) and an uncomfortable virtual reality program viewer group (UVR group, 20 people). Visual function test was performed on all subjects, and the vision therapy training program was applied to the UVR group once a week for 40 minutes 12 times, and then the visual function and SSQ questionnaire were re-evaluated. Subjects with diplopia were 55% in the UVR group and 5% in the CVR group, which was significantly higher in the UVR group, there were differences in stereopsis, exophoria, near point convergence(p<.01) and vergence function(p<.001) between the two groups. After vision therapy, changes in SSQ, stereopsis, near point convergence, and vergence function of UVR user group were positively changed(p<.01). Therefore, cybersickness symptoms are related to visual function, it seems that the vision therapy can be used as a way to alleviate the symptoms of cybersickness.

• Journal of Korean Ophthalmic Optics Society
• /
• v.7 no.2
• /
• pp.143-147
• /
• 2002

A36 patients of a total of 60 persons show $2{\Delta}$ and less, and the rest of 24 patients show $6{\Delta}$ and less. The patient, who increase more in near distance than far distance in exophoria amount are 27 persons. The unchanging patients are 13 persons, and the patients who phoria amount decreasing are 20 persons. Like this, the patients who phoria amount unchange and decrease show more than the half. That is why convergence increases in near distance. The expected value of horizontal phoria in near distance is $3exo{\pm}3$. Only 13 patients get rid of its value, 47 satisfy its value. In AC/A value, 35 persons show under 3(1ow), 21 persons show 3~5(normal), and 4 persons show more than 5(high). By Percival's theory, 36 patients don't feel a slight asthenopia without correcting phoria. Finally, in near point of convergence 27 patients show 10cm and less, 24 patients show 11~15cm, 3 patients show 15~20cm, and 6 patients show 21~25cm. Most of them show high accommodation.

• Journal of Korean Ophthalmic Optics Society
• /
• v.7 no.2
• /
• pp.33-39
• /
• 2002

The purpose of this study is to evaluate the effects of continuing work on VDT(video display terminal). Therefore, we examined visual fatigue by a questionnaire and measured frequency of blinking, tear film break-up time(BUT), height of palpebral fissure, visual acuity, refraction with retinoscopy and accommodation before and after two hour long VDT work. For the ocular symptoms, the greatest number was tired eyes accounting for 34%. In the visual symptoms, blurred vision was the highest rate of 83% and in case of systemic symptoms, shoulder pain was 38% marked top ranking but other symptoms were also distributed similar rate. The frequency of blinking during VDT work decreased significantly comparing with the one at rest. The average frequency of blinking is 8/min during VDT work and 22/min at rest. The BUT measured immediately after VDT work decreased much more than in the resting state. The average BUT was 7sec immediately after VDT work and 12sec at rest. The height of palpebral fissure during VDT work increased significantly comparing with the value at rest. The average height of palpebral fissure was 7.69mm at rest and 9.04mm during VDT work. The average visual acuity decreased almost 9.5% from 0.63 to 0.57, but refraction with retinoscopy increased about 0.28D to the direction of myopic shift. The amplitude of accommodation decreased approximately 1.49D from 7.98D to 6.49D and this resulted from the prolongation of near point of accommodation. Near point of convergence also was prolongated from 9.45cm to 10.30cm after VDT work.

• Journal of Korean Ophthalmic Optics Society
• /
• v.12 no.3
• /
• pp.125-130
• /
• 2007

The aim of this work was to study the relationship between subjective symptoms and binocular function during near work in forty one(12-17yr) schoolchildren. CISS symptom survey, amplitude of accommodation, accommodative facility, neagative relative accommodation(NRA)/positive relative accommodation(PRA) near point of convergence(NPC), heterophoria, AC/A ratios were measured. The results of measurement were compared with normal expected value of each test and classified into normal and abnormal group. Accommodative insufficiency was more general than convergence insufficiency and esophoria was greater than exophoria. NRA/PRA showed very high and AC/A ratios were very low compare with normal expected value. The results of CISS was as follows; most frequent symptom was tired, mean score was $16.63{\pm}7.49$, mean number of symptoms were $10.07{\pm}3.04$, and mean number of serious symptoms were $1.98{\pm}2.13$. After classified into 4 groups according to score of symptoms, number of symptoms, and degree of symptoms and then analyze the correlation compare with binocular vision test results. NRA was most correlated with group comparison, accommodative facility was most correlated with score of symptoms, NRA was most correlated with number of symptoms, and near horizontal phorias were most correlated with serious symptoms. NRA showed most correlative relation with near symptoms.

• Journal of Korean Ophthalmic Optics Society
• /
• v.13 no.4
• /
• pp.127-134
• /
• 2008

Purpose: The purpose of this study was to determine the expected values of accommodation and vergence system for analysis of binocular vision. Methods: Seventy three healty subjects without past history of eye disease were selected for this study, Patients showing clinical binocular anomalies including manifest squint and intermittent heterotropia were excluded and data was collected on 54 patients(mean age, 25.3${\pm}$2.7 year). Near point of convergence, distance and near phoiras were measured based on objective deviation angle. And then AC/ A ratio, relative accommodation were measured and all of the data were compared with the Morgan's expected values. Results: The values of distance and near heterophoria were 1.24${\pm}$2.72${\Delta}$ and 2.70${\pm}$4.91${\Delta}$ respectively and the gradient AC/A ratio was 3.92${\pm}$2.17${\Delta}$/D which were all about the same compared with the Morgan's expected values. The values of distance negative fusional convergence was same, however, distance positive fusional convergence was 7${\Delta}$ greater than the Morgan's one. There were no significant differences in the range values of both near vergences while the range of distance vergence was relatively larger than the Morgan's one. Positive relative accommodation was +0.37D greater and negative relative accommodation was -0.63D greater than the Morgan's values. Conclusions: The findings in this study appear that the Morgan's expected values have a possibilities of including considerable proximal convergence value. In comparison with Morgan's values, Korean's normal expected values have much different values of especially BO limit, so if the Morgan's values are directly applied to binocular vision analysis for Korean people, it may lead to an inaccurate binocular vision diagnosis. This results can be used to diagnose the accommodation and vergence system of Korean normal young adults.

• Journal of Korean Ophthalmic Optics Society
• /
• v.15 no.1
• /
• pp.87-97
• /
• 2010

Purpose: The purpose of this study is to investigate the effects of sports vision training on baseball player's visual performance and baseball records. Methods: All subjects were 21 males of high school baseball players, and they participated on eight weeks of sports vision training program. Pre- and post- test results were obtained for static and dynamic visual acuity, static and dynamic stereo acuity, distance and near phoria, fusional reserves, near point of convergence, contrast sensitivity, visual-reaction time. Results: Statical analysis indicated significant improvement in most of mentioned visual variables and baseball records (p<0.001). Conclusions: It can be concluded that the sports vision training program improves visual skills of baseball players, which could lead to improvement in the baseball records. Vison training will be a promotor for baseball player to enhance their performance if proper test instruments and training course is supplied.