Contrast sensitivities through spectacles and soft contact lenses

Area of Science:

• Ophthalmology
• Optometry
• Vision Science

Background:

• Soft contact lenses are widely used for vision correction.
• Previous studies suggested potential visual impairment with soft contact lens wear.
• The role of astigmatism in soft contact lens-related visual changes requires further investigation.

Purpose of the Study:

• To compare the effects of soft contact lenses versus spectacle lenses on contrast sensitivity function (CSF).
• To investigate potential visual decrements associated with 18-hour continuous wear of soft contact lenses.
• To determine if pre-existing astigmatism influences visual performance with soft contact lenses.

Main Methods:

• Contrast sensitivity function (CSF) measurements were conducted on nine subjects.
• Each subject wore a spectacle lens on one eye and a soft contact lens on the other for 18 hours continuously.
• Subjects had minimal astigmatism (≤0.12 D).

Main Results:

• CSF measurements were identical between the soft contact lens and spectacle lens eyes.
• No decline in visual function was observed over the 18-hour wear period.
• No evidence of visual decrement was found, contrary to earlier reports involving astigmatic subjects.

Conclusions:

• Prolonged wear of soft contact lenses does not immediately affect visual acuity as measured by contrast thresholds.
• Visual impairments previously associated with soft contact lenses may be specific to individuals with significant astigmatism.
• Soft contact lenses are a viable and effective option for vision correction without compromising visual function in non-astigmatic or minimally astigmatic individuals.