Purpose: Basic research to determine clinical validity of the Lea Grating paddles has not yet been conducted. 10 This study involves the evaluation of infant (0 to 18 months) grating acuity with Lea Grating Paddles and Teller Acuity Cards (TAC) in a clinical setting. The goal is to compare the acuity measure obtained with both methods, and establish age-related acuity norms for the newer Lea Grating system.
Methods: Thirty-frve subjects were recruited with parent/guardian consent. Subjects were comprised of newborns and infants ranging in age from 5 days to I 7 months. The assessment of infant visual acuity was performed using the Lea Grating Paddles and the Teller Acuity Cards. Procedural manuals for both techniques were used as reference guidelines. Testing was performed in a standard examination room with normal room illumination. One tester presented the gratings to the infant and determined which direction the infant was looking, while another tester documented acuity levels based on the first tester's observations. Binocular testing followed by monocular testing was conducted. Testing took approximately 15 minutes to complete per child.
Results: T-testing showed no significant difference between the Lea Paddles and TAC binocular means for each four-month interval age group. ANOVA binocular testing for the Lea Paddles and TAC indicated an asymptotic increase in acuity with age, leveling-off starting at four months and older. ANOVA monocular results for both procedures suggested a sigmoidal increase in acuity with age, leveling-off between 4- I 2 months of age. According to the scatter plot, a strong correlation was found for both procedures when means were calculated for the four interval age groups. Correlation coefficient between the Lea Paddles and TAC for binocular and monocular findings were 0.9930 and 0.9910 respectively.
Conclusion: In summary, it was found that any benefit of the Lea Grating Paddles over the TAC is primarily for the clinician. It was easier to obtain the attention of the infants with the Lea Grating Paddles. In addition, the lower cost and increased portability of the Lea Grating Paddles are desirable features for the clinician. While values in this study corresponded with the norms set by the Lea manual, future studies may be useful to establish a larger base of normative data.
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