Tritan colour contrast sensitivity function in refractive multifocal intraocular lenses

Aims-To compare tritan colour contrast sensitivity (CCS), without and with glare, in patients with refractive multifocal intraocular lenses (IOLs) and with monofocal intraocular lenses. Methods-Tritan CCS was determined (Moorfields Vision System, CH Electronics ) in 15 eyes (14 patients, 75.7 (+/-6.6) years) with a refractive multifoca l IOL (Allergan SA 40N) and in 11 eyes (10 patients, 73.7 (+/-6.4) years) w ith a monofocal IOL (Allergan SI 40 NE). Measurements were made monocularly under mesopic conditions at a distance of 2 metres from the monitor with b est distance refraction plus 0.5 D at 0.5, 1, 3, 6, 11.4, and 22.8 cycles p er degree (cpd). The test was then repeated for the multifocal IOLs, adding minus 2.5 D to the best distance refraction to force the patient to use th e near focus. Both lenses were also investigated under glare conditions wit h the same set-up and using the brightness acuity tester (BAT). Results-The tritan CCS function without glare in multifocal lenses through the distance focus was nearly identical to that through the near focus. The following statistically significant differences were measured: the CCS fun ction without glare for the multifocal lens was worse at 0.5 cpd and 1.0 cp d than that of the monofocal lens. In CCS testing of the multifocal group w ith glare at 6 cpd, the results through the distance focus were better than the results through the near focus. For the CCS function with glare, the v alues for the distance focus in the multifocal lens were worse than the val ues for the monofocal lens at 0.5 cpd and 1 cpd. In CCS testing with glare through the near focus and CCS testing through the monofocal lens, the mono focal lens performed better at 0.5 cpd, 1 cpd, 3 cpd, and 6 cpd. Conclusion-Refractive multifocal intraocular lenses influence tritan CCS fu nction compared to monofocal lenses.