RECOGNITION VERSUS RESOLUTION CHARTS FOR DEFOCUS CURVE DETERMINATION IN TRIFOCAL INTRAOCULAR LENSES

Purpose: To determine the impact of optotype choice on the determination of defocus curve in cataract patients implanted with presbyopia-correcting intraocular lens (IOL). Setting: Oftalvist Alicante, Alicante, Spain. Design: Observational case-control study Methods: Patients implanted with Asqelio Trifocal IOL (AST Products, Inc., Billerica, MA, USA) participated in this study. Uncorrected and distance corrected visual acuity and subjective refraction were determined. Monocular defocus curves were obtained 6 months after surgery with the CTS system using either ETDRS or Landolt C charts under photopic conditions (85 cd/m 2 ), and range of vergence from +2.00D to -5.00D in 0.50D steps. Results: A total of 49 patients were enrolled in the study, 24 in the EDTRS group (7 male, 17 female) and 25 in the Landolt C group (5 male, 20 female). Non-significant differences were found between patients conforming both groups, except for preoperative intraocular pressure and white-to-white distance. All patients were within ±1.00D from intended refraction after surgery. 75% of patients in the EDTRS group and 84% in the Landolt C group were within ±0.50D. Average difference between the groups across vergences provided by the defocus curve was 0.12±0.05 logMAR units, significant for all vergences (p<0.05). Differences in VA were significant for distance, intermediate and near between both groups, except for uncorrected distance VA. Conclusion: Defocus curves created using Landolt C charts yield significantly lower through-focus outcomes than those created with standard EDTRS charts. This should be taken into account when comparing the performance of presbyopia-correcting systems accross studies where recognition charts might have been used due to patient characteristics.