Effects of Anterior Chamber Depth and Axial Length on Refractive Error after Intraocular Lens Implantation

ABSTRACT

PURPOSE: To investigate the error tendency between preoperative expected refraction and postoperative manifest refraction based on anterior chamber depth (ACD) and axial length (AXL) in cataract surgery cases and to report how ACD and AXL affect determination of intraocular lens (IOL) power. METHODS: We retrospectively studied 82 eyes of 62 patients who underwent cataract surgery in our hospital between August 2008 and January 2009. Anterior chamber depth and AXL were measured using IOL Master(R), and IOL power was calculated using the SRK II and SRK/T formulae. Patients were divided into three groups based on ACD and into another three based on AXL. Refractive error (RE) was analyzed one month after surgery. RESULTS: Though the RE of each group showed a tendency for hyperopic shifts, only those obtained with the SRK/T formula showed statistically significant differences between groups (p<0.05). Using the SRK/T formula, we found that an increasing AXL was associated with an increased hyperopic shift. This was more pronounced in those with shallow ACD (<2.5 mm), though the difference was not statistically significant. Similarly, an increase in ACD was associated with an increased hyperopic shift, and this difference was more pronounced in those with short AXL (<22.5 mm), and this time the difference was statistically significant. CONCLUSIONS: As ACD and AXL significantly affect RE, both should be considered when investigating postoperative RE tendency and when determining IOL power. Postoperative RE will be greatly affected by a short AXL or a shallow ACD, and therefore these factors should be considered in IOL power determination.