Pseudophakic anterior chamber depth measurement in second eye refinement cataract surgery
Purpose: To study the effective lens position concept in second eye refinement (SER) cataract surgery, by relating inter-ocular symmetry of pseudophakic anterior chamber depth (pACD) and SER refractive outcomes.
Methods: One hundred and twelve patients were identified as having performed bilateral consecutive cataract surgery. Prediction errors for the first and second eyes were calculated for 3 formulae (HofferQ, SRK/T and Holladay1). A 50% adjustment of the first eye prediction error was used in the intra-ocular lens (IOL) power selection of the second eye. Refractive outcomes were compared using the mean absolute error (MAE). Pentacam HR was used to measured pACD, and consecutive 50µm increments in inter-ocular asymmetry were used to assess refractive outcomes.
Results: The resulting MAE after the 50% SER was significantly lower in all formulas compared with no adjustment: 0.30D compared with 0.36D (p=0.009) for HofferQ, 0.26D compared with 0.31D (p=0.022) for SRK/T and 0.27D compared with 0.33D (p=0.012) for Holladay1. The pACD was significantly correlated between the first and second eyes (r=0.714; p<0.001). In all formulas, when the inter-ocular difference in pACD was higher than 350µm (11.36% of patients), the MAE resulting from SER was significantly higher and not different when comparing with the no adjustment group.
Conclusions: To our knowledge this is the first study to relate SER outcomes with the measured effective lens position. SER is a valid and promising strategy to improve cataract surgery refractive outcomes in cases of pACD inter-ocular asymmetry up to 350µm.