• Journal of Korean Ophthalmic Optics Society
• /
• v.18 no.1
• /
• pp.19-25
• /
• 2013

Purpose: The degree of the pupil covered with tinted region of circle soft contact lens was determined according to the illuminant conditions in everyday life and the change of visual acuity by its covering was further investigated. Methods: The circle contact lens having the non-tinted area of 6.2 mm in the center of the lens was applied on 82 eyes in their 20s and their minimum separable visual acuity and minimum legible visual acuity were determined under the luminances of 50 and 370 lux. Results: The covering of pupil was not found when wearing circle contact lens under 370 lux, however, some pupil covering ranged from 0.40 to 1.70 mm was observed in all subjects under 50 lux. The minimum separable visual acuity and minimum legible visual acuity were significantly decreased by the wearing of circle contact lens under 50 lux and the correlation between the larger pupil size of subjects and more decrease of visual acuity was observed. Furthermore, the decrease of minimum separable visual acuity was larger than the case of minimum legible visual acuity indicating that minimum separable visual acuity was largely affected by the covering of pupil. Conclusions: The consideration is necessary for the lens wearers and the manufacturers since the wearing circle contact lens in low-light indoor or nighttime activities may affect directly visual acuity.

• Journal of Korean Ophthalmic Optics Society
• /
• v.21 no.1
• /
• pp.1-10
• /
• 2016

Purpose: The study was aimed to suggest the most effective color of the tinted lenses by evaluating the effect of the prescription with tinted lenses on the visual quality of the elderly at the age of the sixty or more. Methods: The visual acuity of fifty subjects at the age of sixty or more (17 males, 33 females with the averaged age of $71.0{\pm}6.3$) were corrected to have the visual acuity at a far distance of 0.5 or more using a trial lens frame, and non-tinted, brown-tinted, and gray-tinted lenses were randomly applied on the trial frame. The minimum legibility and minimum separability were measured at a far distance in the aspect of the visual acuity and calculated as LogMAR and then, the visual acuity was compared. The stereopsis and contrast sensitivity were also estimated at a near distance in the aspect of the visual function. The participants' preference for tinted lenses and their subjective symptoms of the visual perception and the movement were further surveyed. Results: The best minimum legibility and minimum separability was shown when wearing non-tinted lenses, and brown-tinted and gray-tinted lenses were in the next. The stereopsis and the contrast sensitivity at a near distance and the visual perception was the best when wearing brown-tinted lenses. It was surveyed that the subjective discomfort was the biggest when wearing gray-tinted lenses, and brown-tinted lenses were the best in the aspect of the subjective preference. Conclusions: As the result of this study, it was revealed that the visual acuity and visual function could be improved by the use of tinted ophthalmic lenses however, its change of visual acuity and visual function was not completely correlated with the subjective satisfaction. Therefore, the appropriate color of ophthalmic lenses should be selected in accordance with the individual visual perception and the main vision lifestyle in the elderly generation. From the present study, the use of non- or brown-tinted lens and brown- or gray-tinted lens can be recommended for distance work and near work, respectively, in the elderly generation under the illumination of about 1,000 lux.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.13 no.8
• /
• pp.3444-3451
• /
• 2012

Safety and health related information for the proper use and handing of pesticides is usually printed on the surface of the pesticide products in the form of texts. But, the guidelines or standards for the appropriate presentation of the texts for the pesticide products are most vague or not practical. Thus, this study aimed to provide the preliminary guidelines for the text sizes based on the legibility experiments. To achieve the objective legibility evaluation experiments were conducted to test the effects of different near vision (0.6, ${\geq}0.8$), gender, font type(thick gothic-type and fine gothic-type), thickness of font(plain and bold), and number of syllables(2 and 3 syllables) in the same age group of 20s. The results showed that legibility was different according to the visual acuity (p<0.05), and no other main effects showed statistically significant effects. The 'maximum illegible size' to read at least one word correctly in all the text conditions was 2 pt when the near vision was ${\geq}0.8$, and 2 pt or 3 pt when the near vision was 0.6. The 'minimum legible size' for 100% correct answer was 9 pt for the near vision of 0.6, and 5.3 pt for ${\geq}0.8$, respectively. Mean character size does not read any discomfort in 0.6 was 15.5 pt in both male and female but male was mean 8.5 pt, female was 10 pt in ${\geq}0.8$. Considering these experimental results, it was recommended that the 16 pt or larger characters should be used the important information such as 'Pesticides' or toxicity, and the minimum character size was 9 pt for the less important information.