Simple Questionnaires Can Effectively Screen for Low Vision and Legal Blindness

A single yes-or-no question can efficiently screen for low vision or legal blindness when a comprehensive eye exam is not feasible, according to a study published in Investigative Ophthalmology & Visual Science. This finding could significantly improve access to vision care, particularly in remote areas or large-scale public health studies.

The Challenge of Traditional Vision Assessments

Comprehensive clinical visual acuity (VA) assessments are often impractical in remote studies or large-scale public health initiatives due to cost and logistical constraints. While self-reporting is a cost-effective alternative, its accuracy compared to standard clinical measurements has been questioned.

Developing a Targeted Vision Screening Survey

Researchers at The Ohio State University, led by Yueh-Hsun Wu, PhD, addressed this challenge by developing a 100-item visual acuity survey. Unlike general self-report questionnaires, this survey consisted of items specifically designed to assess everyday tasks requiring different levels of VA. The survey’s development and validation utilized item response theory to establish a strong correlation between performance on these tasks and measured VA. Investigative Ophthalmology & Visual Science

Study Design and Participants

The study involved 385 adults recruited from four U.S. Centers. Each participant underwent visual acuity measurement and completed the researchers’ survey.

Key Findings: Identifying Effective Screening Questions

The researchers analyzed each question’s sensitivity, specificity, and area under the curve (AUC) for identifying low vision and legal blindness. The top 10 questions for low vision screening had an average AUC of 0.81. The question with the highest AUC (0.85) was: “In a fast-food restaurant, can you usually read the posted menus?”

For legal blindness screening, the top 10 questions had an average AUC of 0.77, with the highest AUC (0.8) for the question: “When seated in front of a computer, are you able to read the letters on the keyboard keys?”

Combining Questions for Improved Accuracy

Pairing the 20 highest-ranking questions significantly increased the AUC for both low vision and legal blindness. Adding a third question yielded a little but significant improvement for legal blindness, but not for low vision.

Implications for Vision Care

“Our study demonstrated that a targeted set of functional vision screening items can effectively identify low vision and acuity-defined legal blindness, outperforming past self-report questions,” Wu and colleagues wrote. “The survey provides a variety of items that can be employed in different research or clinical settings for efficient screening.”

This research suggests that simple questionnaires can serve as a valuable tool for identifying individuals who may require further vision assessment, ultimately improving access to care and potentially preventing vision loss.