Paraxial analysis of the depth of field of a pseudophakic eye with accommodating intraocular lens.

PURPOSE: To investigate the depth of field of pseudophakic eye implanted with translating optics accommodating intraocular lenses (AIOLs).

METHODS

Theoretical analyses using paraxial optics equations were used. The crystalline lens in the Navarro eye model was replaced with an AIOL modeled as a thin-lens system with either a single lens element (1E-AIOL) or two element (2E-AIOL). To quantify the depth of field, a reference limit for retinal blur circle diameter was adopted from typical values of depth of field of the normal eye. Effect of various factors including AIOL type, lens element power, implant position, and pseudophakic accommodation on depth of field were analyzed.

RESULTS

Depth of field increased with more posterior positioning of the AIOL and decreased with pseudophakic accommodation by translation of optics. However, the changes did not exceed 0.02 D over the range of factors tested. Effective depth of field, defined as the magnification adjusted depth of field, is relatively independent of the implant position and power combination of AIOL. Effects of varying design factors on the depth of field of AIOL are too small to be clinically observable.

CONCLUSIONS

Although depth of field extends the range of near vision with AIOL, varying design and surgical factors such as depth of implantation and optical power of lens element(s) within clinically practical limits modifies depth of field by an insignificant amount. In the practical sense, attempting to enhance the depth of field of AIOL by varying design factors such as the position of implantation would be unrewarding.