Unilateral intraindividual comparison and bilateral performance of a monofocal spherical and diffractive extended depth of field intraocular lens mix-and-match approach.

BACKGROUND: To evaluate the intraindividual visual performance of a spherical and extended depth of field (EDOF) IOL used in a mix-and-match approach. METHODS: Single centre (tertiary care centre), retrospective consecutive case series. Included patients had uneventful cataract surgery with implantation of a spherical monofocal IOL (CT Spheris 204) in the dominant eye and a diffractive EDOF IOL (AT LARA 829) in the non-dominant eye. Monocular and binocular defocus curves and visual acuity at various distances were assessed. In addition, binocular reading speed, contrast sensitivity, and patient satisfaction using QOV, Catquest 9SF, and glare/halo questionnaires are reported. RESULTS: A total of 29 patients (58 eyes) were included. We observed significant intra-individual differences for monocular DCIVA, DCNVA, UIVA, and UNVA. There were no differences in monocular BCDVA or UDVA. The monocular defocus curves for the two IOLs significantly differed at defocus steps between -1.0 and -3.5 D. 93.10% of patients reported they would opt for the same combination of IOLs. CONCLUSION: Excellent uncorrected and corrected distance visual acuity was demonstrated in both groups. The mix-and-match approach described in this study yielded good intermediate vision and improved near vision with high-patient satisfaction.

Analysis of Biomechanical Response After Corneal Crosslinking with Different Fluence Levels in Porcine Corneas.

PURPOSE: To evaluate corneal stiffening of porcine corneas induced by corneal crosslinking (CXL) with constant irradiance as a function of total fluence. METHODS: Ninety corneas from freshly enucleated porcine eyes were divided into five groups of 18 eyes. Groups 1-4 underwent epi-off CXL using a dextran-based riboflavin solution and an irradiance of 18 mW/cm2, group 5 served as the control group. Groups 1 to 4 were treated with a total fluence of 20, 15, 10.8, and 5.4 J/cm2, respectively. Thereafter, biomechanical measurements were performed on 5 mm wide and 6 mm long strips using an uniaxial material tester. Pachymetry measurements were performed on each cornea. RESULTS: At 10% strain, the stress was 76, 56, 52, and 31% higher in groups 1-4, respectively compared to the control group. The Young's modulus was 2.85 MPa for group 1, 2.53 MPa for group 2, 2.46 MPa for group 3, 2.12 MPa for group 4, and 1.62 MPa for the control group. The difference between groups 1 to 4 and the control group 5 were statistically significant (p = <0.001; p = <0.001; p = <0.001; p = 0.021). In addition, group 1 showed significantly more stiffening than group 4 (p = <0.001), no other significant differences were found. Pachymetry measurements revealed no statistically significant differences among the five groups. CONCLUSION: Additional mechanical stiffening can be achieved by increasing the fluence of the CXL. There was no threshold detected up to 20 J/cm2. A higher fluence could compensate the weaker effect of accelerated or epi-on CXL procedures.

The 10,000 Eyes Study: Analysis of Keratometry, Abulafia-Koch regression transformation, and Biometric Eye Parameters Obtained With Swept-Source Optical Coherence Tomography.

PURPOSE: To analyze Abulafia-Koch regression (AKRT), anterior and posterior astigmatism (K and TK), and evaluate biometry data in a large population. DESIGN: Retrospective cross-sectional study. METHODS: This multicenter (2 tertiary care centers) study analyzed datasets acquired between 2017 and 2020. Axial length (AL), corneal front and back radii (including meridians for K and TK conversion), horizontal corneal diameter, anterior chamber depth, lens thickness, and central corneal thickness were measured using telecentric keratometry and swept-source optical coherence tomography-based biometry (IOLMaster 700; Carl Zeiss Meditec AG). Cooke-modified axial length (CMAL) and AKRT were calculated. Difference vectors between K and TK astigmatism and between AKRT and TK astigmatism were compared. RESULTS: A total of 10,300 eyes from 6388 patients were assessed. Difference vectors for K and TK were significantly smaller than for AKRT and TK. K measurement showed a configuration of 51.49% of with-the-rule astigmatism and 30.51% against-the-rule astigmatism, TK measurement showed a configuration of 41.60% of with-the-rule astigmatism and 40.21% against-the-rule astigmatism. Mean total astigmatism was -0.94 ± 0.74 dpt. Mean values for AL and CMAL were 23.70 ± 1.39 mm and 23.70 ± 1.34 mm, respectively. Anterior chamber depth, lens thickness, horizontal corneal diameter, AL, and age were all correlated with each other. CONCLUSION: Astigmatism analysis showed less difference between K and TK than between AKRT and TK. There were significantly fewer eyes with with-the-rule astigmatism and more eyes with against-the-rule astigmatism configuration in TK-derived than in K-derived keratometry. The study provides data on gender and generational differences in biometry. Significant intersexual differences in AL and CMAL were observed, with CMAL providing lower standard deviation compared with AL.

Project Hyperopic Power Prediction II: The Effects of Second Eye Refinement Methods on Prediction Error in Hyperopic Eyes.

PURPOSE: The purpose of the study was to evaluate the potential accuracy of different second eye refinement methods in a patient cohort with short axial eye length to assess the performance of intraocular lens (IOL) power calculation schemes in high hyperopes. METHODS: The study design was a single-center, single-surgeon retrospective consecutive case series. The setting of the study was in Augen- und Laserklinik, Castrop-Rauxel, Germany. Patients were assessed after uneventful bilateral cataract surgery implanting either spherical (SA60AT) or aspheric (ZCB00) IOLs. Inclusion criteria were an axial eye length of ≤21.5 mm and/or emmetropizing IOL power of >28.5 dpt. Outcome measures were the mean absolute prediction error (MAE), median absolute prediction error, mean prediction error with standard deviation, median prediction error, and the percentage of eyes with an absolute prediction error (absPE) within 0.25 dpt, 0.5 dpt, 0.75 dpt, or 1.0 dpt. Second eye refinement was performed using the first eye prediction error, either with a correction coefficient of 0.50 (SER1), or an individual coefficient optimized for MAE. RESULTS: A total of 55 patients were assessed. A statistically significant reduction in the absPE after the application of SER1 was observed in 9 of 13 formulae. The SER1 refined Hoffer Q, refined Holladay I, refined Holladay II, refined Kane, refined Okulix, and refined PEARL-DGS provided a smaller absPE than other methods. CONCLUSION: In this patient cohort with a short axial eye length, the second eye refinement led to a lower MAE in almost all formulae. The use of refinement in Kane, Okulix, PEARL-DGS, and Castrop formulae exhibited the lowest MAE.