Contrast Sensitivity in Patients With Emmetropic Presbyopia Before and After Small-Aperture Inlay Implantation

Area of Science:

• Ophthalmology
• Vision Science
• Biomedical Engineering

Background:

• Presbyopia significantly impacts visual function, necessitating effective correction methods.
• Contrast sensitivity is a crucial measure of visual performance, affected by aging and ocular conditions.
• Intracorneal inlays offer a potential solution for presbyopia correction.

Purpose of the Study:

• To establish normative contrast sensitivity (CS) function for a presbyopic population.
• To evaluate postoperative CS outcomes in emmetropic presbyopic patients implanted with the KAMRA intracorneal inlay in their non-dominant eyes.

Main Methods:

• A prospective, non-randomized, multicenter clinical trial involving 507 patients (45-60 years) monocularly implanted with the KAMRA inlay.
• Contrast sensitivity was measured pre- and postoperatively using the Functional Acuity Contrast Test (FACT) under various lighting and glare conditions.
• Normative ranges were derived from preoperative data using 1.96 standard deviations from the mean logCS.

Main Results:

• Preoperative measurements were used to develop normative contrast sensitivity curves.
• Postoperative contrast sensitivity remained stable monocularly and binocularly, generally within normative ranges.
• A mild monocular reduction in CS was observed, but binocular CS was unaffected; area under the logCS function ratio exceeded 90% compared to preoperative values.

Conclusions:

• Established normative contrast sensitivity curves for presbyopic individuals.
• These curves serve as a benchmark for assessing visual impact of presbyopia-correcting procedures.
• KAMRA inlay implantation demonstrated stable and acceptable postoperative contrast sensitivity outcomes.