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Threshold visual acuity testing of preschool children using the crowded HOTV and Lea Symbols acuity tests
Lynn Cyert1, Paulette Schmidt, Maureen Maguire
1Northeastern State University, College of Optometry, Tahlequah, OK, USA.
Insights
Visual acuity testing in young children showed crowded HOTV charts yielded better results than Lea Symbols charts. Both methods proved highly testable for assessing visual acuity in preschoolers.
Area of Science:
- Ophthalmology
- Pediatric Optometry
- Vision Science
Background:
- Accurate visual acuity assessment in preschool-aged children is crucial for early detection of vision impairments.
- Standardized tests are needed to compare different optotype presentations and their effectiveness in young populations.
Purpose of the Study:
- To compare the testability and threshold visual acuity levels of the crowded HOTV logMAR (linearity of the logarithm of the minimum angle of resolution) distance visual acuity test presented on the Binocular Vision Assessment Tool (BVAT) apparatus versus the Lea Symbols logMAR distance visual acuity chart.
- Evaluate the efficacy of two distinct visual acuity tests in very young children.
Main Methods:
- 87 Head Start children aged 3 to 3.5 years participated.
- Testing involved binocular pretraining at near and 3 meters, followed by threshold testing for each eye using a modified Amblyopia Treatment Study protocol.
- Optotypes were presented until a specific failure criterion was met; threshold acuity was the smallest size correctly identified for at least three optotypes.
Main Results:
- Testability was high and similar for both HOTV (71%) and Lea Symbols (75%) charts.
- The distribution of threshold acuities differed significantly between the two tests (P <.001).
- Crowded HOTV acuity results were, on average, 0.25 logMAR (2.5 lines) better than Lea Symbols acuity results for the 53 children tested with both.
Conclusions:
- Monocular visual acuity assessment was feasible in a high proportion of children aged 3 to 3.5 years using both HOTV and Lea Symbols charts.
- Crowded HOTV acuity testing yielded significantly better results compared to Lea Symbols testing.
- Differences in optotype format and presentation likely account for the observed variations in threshold acuity measurements.
Purpose:
To compare the testability and threshold acuity levels for very young children on the crowded HOTV logMAR distance visual acuity test presented on the BVAT apparatus and the Lea Symbols logMAR distance visual acuity chart.
Methods:
Subjects were 87 Head Start children from age 3 to 3.5 years. Testing consisted of binocular pretraining at near using a lap card as needed, binocular pretraining at 3 m, and threshold testing for each eye. The testing procedure, adapted from the Amblyopia Treatment Study, presented optotypes until the child was unable to correctly name or match three of three or three of four optotypes of a given size. Threshold acuity was the smallest size for which at least three optotypes were correctly identified.
Results:
Both near and distance pretraining were completed by 71% of children for HOTV and by 75% for Lea Symbols (P =.39). The distribution of threshold acuities differed between the two tests. For the 69 eyes of 53 children who were successfully tested with both optotypes, results from the crowded HOTV acuity test were on average 0.25 logMar (2.5 lines) better than those from the Lea Symbols acuity test (P <.001).
Conclusions:
The proportion of children between 3 and 3.5 years of age whose monocular visual acuity could be assessed was high and was similar for the two charts tested. Crowded HOTV acuity results were better on average than results using Lea symbols. The different formats of the two tests may explain the observed differences in threshold acuity level.
