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Random word recognition chart helps scotoma assessment in low vision.
Manfred MacKeben1, Unni K W Nair, Laura L Walker
1*PhD †MD The Smith-Kettlewell Eye Research Institute, San Francisco, California (MM, LLW, DCF); Frank Stein and Paul S. May Center for Low Vision Rehabilitation, Pacific Medical Center, San Francisco, California (UKWN, DCF); and Envision Inc, Wichita, Kansas (LLW, DCF).
SKread, a new vision test using random words, accurately measures reading ability based on eyesight, not reading skill. It helps identify scotoma location by analyzing reading errors, aiding patient education.
Area of Science:
- Ophthalmology
- Visual Science
- Clinical Research
Background:
- Reading performance is influenced by both visual acuity and linguistic processing.
- Existing reading tests may not fully differentiate between visual impairment and reading skill.
- Assessing reading speed and errors is crucial for understanding visual function in patients with eye conditions.
Purpose of the Study:
- To evaluate SKread, a novel vision test utilizing random word sequences.
- To determine if SKread can reliably measure reading performance independent of linguistic prediction.
- To assess the clinical utility of SKread for scoring in a healthcare setting.
Main Methods:
- SKread was developed by combining MNread's format with random word/letter sequences (similar to Pepper Visual Skills for Reading test).
- 231 subjects (136 with maculopathy, 65 with normal vision) and 30 healthy controls participated.
- Monocular visual acuity and reading performance (speed, errors) on continuous text and random words were measured.
Main Results:
- Reading speed was significantly slower for SKread (random words) compared to MNread (continuous text) in both normal and maculopathic subjects.
- Error types (left/right errors) correlated with the location of scotomas relative to fixation.
- SKread demonstrated good test-retest repeatability and minimal dependence on age or visual acuity for error patterns.
Conclusions:
- The use of unpredictable random word sequences in SKread makes reading performance more sensitive to visual acuity than reading skill.
- Specific error patterns in SKread can non-invasively indicate the presence and location of scotomas.
- SKread provides valuable insights for patient education on how scotomas impact vision.
