• Korean Journal of Optics and Photonics
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• v.15 no.5
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• pp.461-468
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• 2004

A finite model eye of visual acuity 24/20 in emmertropia was presented. We determined the image intensity profile on retina using optical transfer function of model eye, and compared with clinical data. The retinal contrast sensitivity function based on the Stiles-Crawford effect, photopic response, diffraction, aberration, retinal contrast sensitivity, and pupil size is calculated. Visual acuity for human eye could be predicted by examining the modulation transfer function of a bar target and retinal contrast sensitivity function. This visual acuity was evaluated for pupil diameters ranging from 1 to 8 mm.

• Journal of Korean Ophthalmic Optics Society
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• v.12 no.4
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• pp.95-99
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• 2007

This study performed apreliminary test with male high school students in Gwangju metropolitan city in order to determine visual function information of high school students. For the items in this preliminary test, there were inquiry, test for long distance unaided visual acuity, pinhole visual acuity test, colour vision test, cover test and stereo test. Most complaint related to eye was about blurred vision (28.4%) and over 90% of subjects had one or more, and among them, over 50% appealed two or more complaints. 76.1% of all subjects showed less than 0.7 in unaided distance visual acuity. In pinhole visual acuity test, 98% had an improved unaided pinhole visual acuity and most of them experienced an improvement and 2% had no change or dropped. The students with normal stereoscopic vision test were 85.6% and the students under normal range were 14.4%. In colour vision test, 7.9% of them were protanomaly and deuteranomaly and none of them had trichromasy and total color blindness. In cover test, it showed 30.2% of orthophoria, 8.2% of esophoria and 61.5% of exophoria, and none of them had strabismus.

• The Journal of the Korea Contents Association
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• v.16 no.12
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• pp.132-142
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• 2016

The study aimed to examine the state of visual acuity tests in preschoolers and determine the factors affecting the deterioration of their vision. A total of 172 pair, child aged 5-7 years and either one of their parents, were recruited from childcare centers or kindergarten between August 2015 and January 2016. Questionnaires were administered to the parents, and the children's visual acuities were measured. Using forward selection in logistics regression analysis, factors affecting vision deterioration were elucidated. Of 172 children, 128 (74.4%) had undergone a visual acuity test previously and 77 (44.8%) showed a deterioration in their vision. Children who had undergone their first visual acuity test after the age of 7 years (OR=7.425, CI=2.844- 19.385) and showed more abnormal eye symptoms, such as squinting or tilting the head to see or falling down frequently (OR=3.084, CI=1.202-7.914) and whose age was younger (OR=10.335, CI=3.252-32.848), were more likely to develop deterioration of vision. Children who had a posture such that they looked up at the computer monitor from below (OR=.075, CI=.022-.255), were less likely to show deterioration of vision. It can be inferred that early visual acuity tests is essential to detect deteriorated vision of preschoolers. Therefore, it is necessary to educate parents, personnels in day care center, and health clinics about the importance of early visual acuity tests and close observation of specific behaviors related to vision deterioration. Development of precautionary intervention program of vision deterioration in preschoolers and examination of its effects are needed.

• Journal of Yeungnam Medical Science
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• v.11 no.1
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• pp.153-159
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• 1994

Extracapsular cataract extraction with posterior chamber intraocular lens in 24 eyes of 24 diabetics, with and without diabetic retinopathy, were followed up postoperatively for an average of 14 months to determine the incidence of progression of diabetic retinopathy, the final visual acuity and factors predictive of progression of retinopathy and final visual acuity. Overall, retinopathy progressed in 52% of operated-on eyes. Cataract extraction was highly associated with progression of diabetic retinopathy. Women had a significantly increased risk of progression of retinopathy in the operated-on eye compared to men. Visual acuity improved in 22 of 24 orerated-on eyes : however, only 11 eyes achieved a visual acuity of 0.5 or better and only 7 eyes achieved a visual acuity of 0.7 or better. Patients treated with oral hypoglycemic agents had a worse visual prognosis than those treated with insulin. The prognosis of patients with diabetic retinopathy about to undergo cataract surgery, even extracapsular cataract extraction with placement of a posterior chamber lens, is guarded.

• Proceedings of the IEEK Conference
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• 2000.06e
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• pp.103-105
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• 2000

Optokinetic nystagmus(OKN) testing is an useful tool for assessment of human visual function. Specially, this method has been used for assessing visual function in infants and malingering patients. OKN drum and OKN tape are the common devices currently used for clinical cases. In this paper, we present newly the automated and computerized method for the quantitative and objective assessment of visual acuity in OKN testing.

• Journal of Preventive Medicine and Public Health
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• v.34 no.2
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• pp.175-181
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• 2001

Objectives : To compare the multiple outcomes of patients with cataract surgery at perioperative time,3-4 months and 12 months after surgery and to assess patient outcomes associated with visual improvement(visual acuity of operated eye, visual function-14(VF-14), symptom score). Methods : For this assessment, a prospective study was conducted with 389 patients who had undergone cataract surgery for either one eye or both eyes. The surgery was peformed by 20 ophthalmologists who were practicing at university hospitals and general hospitals. Patients were interviewed and clinical data were obtained. Doctors were questioned with self-reported questionnaire forms. Medical records were examined in order to measure variables related to the surgical process such as surgical methods and ocular comorbidity. The survey was 'conducted at 4 stages' : preoperative time(389 cases), perioperative time(344 cases, 88.4%), postoperative 3-4 months (343 cases, 88.2%), and postoperative 12 months (281 cases, 72.2%). After excluding cases with incomplete data, 198 cases were enrolled in the study. Patient outcomes was measured for any improvement in the functional outcomes(visual acuity of operated eye, visual function, symptom score) at postoperative 3-4 months. Results : The visual acuity(operated, weighted average), symptom score, VF-14 score, satisfaction with vision, and subjective health status were shown to be improved at the perioperative time, postoperative 3-4 months and 12 mouths. An improvement in the Snellen visual acuity score was observed in 190 patients(96.0%), whereas improvements of the VF-14 score and cataract symptom sure were observed in 151 patients(76.3%) and 179 patients(90.4%), respectively. All three outcome measures demonstrated improvement in 137 patients(09.2%). The improvement of the three functional outcomes at 3-4 months after receiving surgery was associated with a lower level of visual function and a higher level of cataract symptom score at perioperative time, as well as a greater experience level of the surgeon. Conclusions : In this study, the estimates of the proportion of patients benefiting from cataract surgery varied with the outcome measure of benefit. Preoperative VF-14 score, a measure of functional impairment related to vision, and symptom score may be better measures of the benefit derived from cataract surgery than the change in visual acuity.

• Journal of Korean Ophthalmic Optics Society
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• v.20 no.3
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• pp.355-362
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• 2015

Purpose: To investigate the effects of the transmittance of diffusive blurson visual acuity and contrast sensitivity. Methods: Visual acuity and contrast sensitivity were measured by using Optec$^{(R)}$ 6500 in Healthy 30 subjects aged $22.83{\pm}0.50$ (male 13, female 17) who were recruited from university students. Cataract simulator was used as a tool for diffusive blur. Visual acuity and contrast sensitivity were measured with varying the transmittance of diffusive blur in order to simulate progression of cataract and concentration in fog. Results: Visual acuity was reduced proportionally with decreasing the transmittance of the diffusive blur as follows: $VA(T)=1.84{\times}10^{-2}T-0.645$. Contrast sensitivity was decreased in all spatial frequencies. Contrast sensitivity in a high spatial frequency band was a greater effect and was off the normal range of contrast sensitivity. The peak of contrast sensitivity was moved in the direction to low frequency. From an intersection point of contrast sensitivity function, we could calculated the transmittance of the diffusive blur being off the normal range and the shift to peak spatial frequency. The peak of contrast sensitivity function was observed to move from 6 to 3 cpd at transmittance of about 78.70%, the contrast sensitivities for all frequencies at transmittance of about 69.71% were deviated from the normal range. Conclusions: The transmittance of diffusive blur causes a reduction in visual acuity and contrast sensitivity, a deviation of normal range of contrast sensitivity, and a shift of peak contrast sensitivity. Therefore the more attention is required when suffering from cataracts or driving in fog.

• Journal of Korean Ophthalmic Optics Society
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• v.3 no.1
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• pp.87-92
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• 1998

Unaided visual acuity was tested by ACP-7 TOPCON chart projector on 376 kindergarteners and objective refraction error was measured by NIDEK ARK-700A auto-refractokeratometer on 554 eyes aged 3 to 5. The results were as follows ; The average unaided visual acuity of children aged 3 was 0.82, aged 4 was 0.90 and aged 5 was 0.92 respectively theerfore children s visual acuity has been gradually developed with their age. The kind of refractive error was 1% for hyperopia, 14% for hyperopic astigmatism, 3% for myopia, 50% for myopic astigmatism, 18% for mixed astigmatism and 14% for emmetropia respectively.

• Journal of Korean Neurosurgical Society
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• v.44 no.1
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• pp.43-46
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• 2008

A 35-year-old man's vision had progressively deteriorated over a 3-month period. His left visual acuity was 5/20. Enhanced orbital computed tomographic (CT) scans revealed a fusiform dilatation of the ophthalmic artery in the left optic canal. Cerebral Angiography revealed a fusiform aneurysm on the left ophthalmic artery in the optic canal, measuring $6.2{\times}4.6\;mm$ in size. Four days after admission, visual acuity dropped to hand-motion. Endovascular treatment was chosen and a microcatheter was guided into the proximal segment of the ophthalmic artery. Using 4 detachable coils, parent artery occlusion was done. Three months after the intervention, the visual acuity in his left eye improved to 20/20. Dramatic recovery of visual acuity is exceptional with an ophthalmic artery trunk aneurysm. When an occlusion of the proximal ophthalmic artery is the only treatment option in such a situation, the endovascular occlusion of the proximal ophthalmic artery is quite feasible in the sense that it does not require any optic nerve manipulation.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.17 no.2
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• pp.112-119
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• 2004

Objective: To carry out the oriental medical treatment on a patient with vitreous hemorrhage in the left eye caused by diabetic retinopathy and record the results of the treatment. Methods: 1. Diagnosis: Fundus photography, Colored paper, Dr. Hahn's standard test chart for 5M, Blood sugar measurement. 2. Treatment: Acupuncture, Electro-Acupuncture, Indirect moxibustion, Western medicines, Oryoungsan(Crude drug preparations) Results: Oriental treatment using Ohaeng-acupuncture, Electro-Acupuncture, Indirect moxibustion resulted in the Unaided visual acuity of 0.1 while it used to be the left eye visual acuity with only light sense I month ago. Looking from Fundus photography result, progress was achieved and diabetic retinopathy was found to be in progress in fluorescein fundus angiography to right eye also by revisiting the patient after treatment. Conclusions: 1. Vitrectomy has many advantages but there are instances where patients do not recover their visual acuity due to complications. Therefore it is necessary to prove the effect oriental medical treatment through more cases in future. 2 For diabetic retinopathy patients, diabetes must be treated together with visual acuity.