Usefulness of Computerized Objective Visual Acuity Test System Using Suppression Method

PURPOSE: The objective visual acuity test is mandatory in certain cases, such as infants, nonverbal subjects, and subjects who need legal assistance. We designed an objective system for visual acuity test (SOVAT) consisting of three components: stimuli applied via a suppression method, display and evaluation and made a suppression method as stimuli component for SOVAT. Usefulness of the SOVAT was evaluated. METHODS: The visual stimuli were presented on a high-resolution head-mounted display (HMD). An eye movement tracking program and gaze monitoring device allowed us to monitor the patient's fixation status during the test. The suppression method, in addition to a conventional induction method, was developed to use with the SOVAT and its accuracy and confidence level were evaluated. RESULTS: On the basis of clinical data, we present the reference values for the SOVAT as below. For the induction method, objective visual acuity (smallest pixel size), the presumed subjective visual acuity was 3: 0.35-0.6, 7: 0.05-0.25, 12: below 0.05 and for the suppression method it was 1: 0.6-1.0, 1.5: 0.4-0.7, 3: 0.15-0.4, 5: 0.1-0.2. CONCLUSIONS: SOVAT using this suppression method to assess objective visual acuity proved to be more useful than that with a conventional induction method, especially in the range of high visual acuity.

Corneoscleral cyst treated with distilled water injection

To describe the first case of the treatment of a corneoscleral cyst by distilled water injection into a corneal cyst. The anterior wall of a cyst of the limbal communication was punctured with a surgical blade. Aspiration and irrigation of the contents of the cyst with a 27-gauge anterior chamber cannula were performed repeatedly, three times. Distilled water, instead of balanced salt solution, was injected into the collapsed cyst, and was then aspirated completely after 5 minutes. The injection and aspiration of distilled water was repeated once more. The scleral cyst was surgically excised. Twelve months after surgery, several small white granular opacities, presumably epithelial cell nests, were observed on the interface of the collapsed cyst cavity, but there was no recurrence of the cyst. The best spectacle-corrected visual acuity (BSCVA) was 1.0 with a correction of +1.25-2.00 X 45. No significant change in central corneal endothelial cell density was noted. We suggest that this simple technique may represent an alternative method for the management of corneal cysts, and may have less risk of developing a corneal opacity or causing other serious damage to surrounding tissues.

Seohan Computerized Hue Test(2): Total Error Scores According to the Age in Normal Subjects and Total Error Scores and Central Cap in Color Defectives

PURPOSE: To evaluate the clinical usefulness and its own characteristic of Seohan computerized 85-hue test(SCHT-85) which was developed by authors. METHODS: SCHT-85 was performed in 89 normal subjects and 41 subjects with color defects diagnosed by Hardy-Rand-Rittler test(HRR test) and Farnsworth Munsell 100-hue test(FM 100-hue test) and total error scores(TES) according to the age in normal subjects and TES and central cap in subjects with color defects were determined. RESULTS: In normal subjects, TES of SCHT-85 according to the age were slightly higher than those of FM 100-hue test and highly correlated with those of FM 100-hue test. TES of SCHT-85 were increased according to the degree of abnormality in the HRR test in subjects with color defects. TES of SCHT-85 were lower than those of FM 100-hue test in normal subjects and higher than those of FM 100-hue test in subjects with color defects. In subjects with color defects, the central cap of SCHT-80 showed the tendency to yellowgreen-purple axis in protan and green-bluepurple axis in deutan compared to that of FM 100-hue test. CONCLUSIONS: SCHT-85 is highly correlated with FM 100-hue test and seems to be more useful to differentiate normal subjects and subjects with color defects than FM 100-hue test.

The Developement of An Objective Test for Visual Acuity Assessment Using Optokinetic Nystagmus Stimuli Presented Head-Mounted Display: Seohan Objective Visual Acuity Test

The objective visual acuity test is mandatory in certain cases, such as infants, nonverbal subjects and subjects who need legal judgements. To produce more reliable objective method, we made a new objective system for visual acuity test which is called Seohan visual acuity test(SVT). The SVT system has three elements such as stimuli, display and evaluation. For the visual stimuli, the computer program for optokinetic nystagmus(OKN)test was set up in personal computer to control the size, speed and direction of the stimuli easily. The visual stimuli are presented on HeadMounted-Display(HMD)to separate the stimuli from the environment to keep the uniform size and distance of screen to the eye of subjects and project the stimulus in full central field of patient. Electrooculography(EOG) was used to assess the visual acuity more objectively. To evaluate the usefulness of SVT, the smallest size of the stimulus to elicit OKN(objective visual acuity)with SVT was obtained in 10 eyes in each twelve grade of subjective visual acuity(decimal V). Objective visual acuity(VA)were distributed from 8.3+/-1.87 to 21.4+/-3.1 and showed high correlation(p<0.00 ). The relationship between the objective VA obtained from SVT and subjective VA make a regression line(y=-12.874X+21.303).Subjective VA could be obtained from conversion of objective VA with 95%confidence belt. In conclusion, the objective visual acuity with SVT is highly correlated with subjective visual acuity and SVT using the OKN response to stimuli presented on HMD by the computer program can be useful in assessing visual function objectively.