ABSTRACT
Clinical relevance: The development of region-specific norms for the Developmental Test of Visual Perception, third edition (DTVP-3), from a group of children from South India will contribute to the assessment of visual-perceptual skills in children.Background: Visual-perceptual skills are crucial for children to understand their environment, perform activities of daily living, and cope with their learning environment. These perceptual skills also influence children's behavioural characteristics. Well-constructed, norm-referenced standardised tools are vital for assessing visual-perceptual skills. Since ethnicity and cultural background may influence the performance of perceptual tasks, the proposed norms for any assessment tool need to be validated for specific populations. Hence, the current study aimed to develop norms in the Indian context for the Developmental Test of Visual Perception, third edition (DTVP-3), and compare the obtained norms with the norms established in the United States of America.Methods: One hundred and thirty-seven healthy children (mean age: 9.5 ± 1.7 years, range: 7-12 years, 67 females) participated in the study. Visual-perceptual functions including eye-hand coordination, copying, figure-ground, visual closure, and form constancy, were assessed and compared with age-matched norms provided in the test manual. Internal consistency of DTVP-3 was evaluated using Cronbach's Alpha correlation coefficients.Results: Significant differences were observed between the study groups and the given norms for assessment of the abilities of eye-hand coordination, copying skills and visual figure-ground (p < 0.05). No significant difference was found for visual closure and form constancy subtests. Cronbach's alpha coefficients for the five subtests ranged from 0.70 to 0.91 while the composite indexes had coefficients from 0.90 to 0.93.Conclusion: The DTVP-3 showed acceptable limits of internal consistency when tested in a group of children from South India. Region-specific norms need to be used for each of the subtests.
Subject(s)
Activities of Daily Living , Visual Perception , Child , Female , Humans , India , United StatesABSTRACT
BACKGROUND AND AIMS: Watching 3D images are known to induce more ocular, systemic fatigue and discomfort, which can be referred to as '3D asthenopia', than watching two-dimensional (2D) images. This study was designed to determine the stereo acuity levels among college students and compare it with the hours of use of digital technology. METHODS: University students in the age group of 18-25 years were screened for visual acuity for distance and near. Refraction was done to find the presence of refractive errors. Those students who had no vergence or accommodation dysfunction and orthophoria were only included in the study. Stereopsis was assessed using random dot stereo acuity chart. The stereo acuity results were grouped as either normal (20 arc seconds or better), Borderline (25 arc seconds to 40 arc seconds) and reduced stereopsis (50 arc seconds to 400 arc seconds). Students were also questioned about the hours of use of digital media. RESULTS: The average age of the 246 participates was 20 ± 1.9 years with 78 (32%) were males and 168 (68%) were females. 7% of the population was found to be myopic in our study. The hours of use of digital technology ranged from 0-9 hours a day. Only 13.1% of the student's population met the normal level of stereopsis (20 arc seconds). Around 44.3% of the study population was found to have borderline stereopsis. Also 42.6% of the study population, reduced stereopsis was found. Among the reduced stereo acuity levels, we found stereoacuity levels as low as 100-200 arc seconds were found in nearly 17.6% of the study population. CONCLUSION: It is very much evident from this study that a large group of college students are not enjoying the highest level of binocular vision, which in turn can have a negative impact on their academic performance.
ABSTRACT
PURPOSE: To find a novel method for calculation of the initial trial spherical rigid gas-permeable contact lens fitting in pellucid marginal corneal degeneration (PMCD) to reduce the number of trial fitting required to achieve a best fit. METHOD: A retrospective data of 16 subjects (8 men and 8 women) who were diagnosed to have PMCD and under went contact lens trial were selected after reviewing the medical records of the patients who visited medical research foundation over a period of year. The demographic details, refractive error, details of lens trial, dispensed lens parameters, fluorescein pattern achieved, and simulated keratometry (Sim-K) reading were noted. RESULTS: Of the 32 eyes (16 subjects), 6 eyes (4 subjects) continued with glasses. Three eyes were advised deep anterior lamellar keratoplasty (DALK). Twenty-three eyes were fitted successfully with gas-permeable lens and achieved vision between 6/9 and 6/6. The base curve of the final lens achieved was compared with the calculated appropriate base curve by stability factor method, flat keratometry readings, and average keratometry readings. Analysis showed no significant difference between the final lens base curve and the calculated appropriate base curve by stability factor method, with a P value of 0.71 and correlation coefficient of 0.77. The average lens diameter was 9.02 mm, with average optic zone of 7.5 mm. CONCLUSIONS: Calculation of appropriate base curve of the lens by stability factor method is found to be the best method to start with a trial in PMCD.
