Objective and subjective measurement of tonic accommodation

Area of Science:

• Ophthalmology
• Optometry
• Vision Science

Background:

• Tonic accommodation (TA) is crucial for visual comfort and performance.
• Understanding TA is vital for managing visual disorders like anomalous myopias.
• Digital screen use is associated with asthenopia and accommodative dysfunction.

Purpose of the Study:

• To compare the efficacy of three distinct optometric techniques for measuring tonic accommodation.
• To assess the reliability and correlation between He-Ne laser optometry (HNL), infra-red optometry (IR), and near retinoscopy (NR) for TA assessment.
• To determine the clinical utility of these TA measurement methods for managing vision problems.

Main Methods:

• Tonic accommodation was measured in 25 subjects under darkroom conditions.
• He-Ne laser optometry (HNL), infra-red optometry (IR), and near retinoscopy (NR) were employed.
• Control studies under cycloplegia were conducted to validate the measurements.

Main Results:

• All three techniques yielded comparable mean estimates of tonic accommodation (HNL: 1.10 D; IR: 1.15 D; NR: 1.07 D).
• Strong significant correlations were observed between HNL and IR (r = 0.88, p < 0.001) and HNL and NR (r = 0.81, p < 0.001).
• Measurements were not significantly affected by accommodative fluctuations, as confirmed by cycloplegia studies.

Conclusions:

• He-Ne laser optometry, infra-red optometry, and near retinoscopy are reliable methods for assessing tonic accommodation.
• These validated techniques provide ophthalmic practitioners with crucial refractive data.
• The findings support the clinical management of anomalous myopias and asthenopia related to VDU work.