Should SPOT (Screening Plus Optotype Testing) screening be performed with or without corrective glasses?

SPOT Vision Screening Should Be Performed Without Corrective Glasses

SPOT vision screening should be performed without corrective glasses to obtain the most accurate assessment of a patient's uncorrected refractive errors. 1

Rationale for Screening Without Glasses

Detecting True Refractive Errors

• SPOT screening is designed to detect amblyopia risk factors and refractive errors in their natural state
• When performed without corrective lenses, the screening provides an accurate baseline of the patient's uncorrected vision 2
• Screening with glasses in place would only measure residual refractive error not corrected by the current prescription, rather than the true refractive status

Alignment with Clinical Practice Guidelines

• According to the Pediatric Eye Evaluations Preferred Practice Pattern, instrument-based vision screening (including photoscreening devices like SPOT) is designed to measure risk factors for amblyopia, not actual visual acuity with correction 1
• These devices are particularly valuable for detecting amblyopia risk factors in young children because the tests are rapid, noninvasive, and require minimal cooperation 1

Accuracy Considerations

• Research shows that SPOT vision screeners demonstrate fair sensitivity and good specificity in detecting refractive errors such as astigmatism (76%/86%), strabismus (50%/96%), and anisometropia (75%/90%) when used without corrective lenses 2
• The device is calibrated to detect uncorrected refractive errors that exceed established thresholds for amblyopia risk factors 3

Special Considerations

For Patients Already Wearing Glasses

• Children who fail vision screening while wearing glasses nearly always need an updated prescription and often have more severe refractive errors than those not wearing glasses 4
• For patients already wearing corrective lenses, two approaches may be considered:
  1. Primary screening without glasses to determine total refractive error
  2. Secondary screening with glasses to assess the adequacy of current correction

Age-Specific Factors

• For preschool children, SPOT screening without glasses is particularly valuable as they may be unable to participate in subjective visual acuity testing 1
• For older children and adults who can participate in subjective testing, visual acuity testing should be performed both with and without habitual correction 1

Technical Considerations

Accommodation Effects

• Young children may accommodate during testing, which can reduce the manifest hyperopia by up to 3 diopters in some cases 5
• Testing without glasses allows for detection of the full range of refractive error without the confounding effect of partial correction

Variations in Performance

• The sensitivity of SPOT screening may vary based on ocular pigmentation, with different performance characteristics for detecting myopia versus hyperopia across different pigmentation groups 3
• The device shows excellent detection of myopia across all eye pigmentation types but variable sensitivity for hyperopia 3

Common Pitfalls to Avoid

1. Don't confuse screening with comprehensive examination: SPOT screening is not a substitute for a complete eye examination with cycloplegic refraction 1

2. Don't rely solely on SPOT results: Children who fail screening or are untestable should be referred for comprehensive eye examination 1

3. Don't misinterpret results as visual acuity values: Refractive error estimates from photoscreening should not be converted to visual acuity values 1

4. Don't overlook the need for follow-up: Children who fail SPOT screening require proper referral, as studies show that 82% of referred cases need further therapy 2

By performing SPOT vision screening without corrective glasses, clinicians can obtain the most accurate assessment of a patient's true refractive status and identify those at risk for amblyopia and other vision disorders that may impact morbidity and quality of life.