Paraxial Analysis of the Depth of Field of a Pseudophakic Eye with Accommodating Intraocular Lens

Abstract

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 modelled 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 analysed. 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 While 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.

Refractive surgery beyond 2020

“…They may be placed either in the sulcus or inside the capsular bag [172]. Single-optic AIOL have flexible supporting elements to transmit ciliary muscle contraction into an anterior displacement of the lens optic, resulting in increased dioptric power of the eye to improve near vision [173]. Experimental evidence suggests that beyond 6 months, the emptied capsular bag is unable to provide any significant dynamic force to an intracapsular located device [174], suggesting that sulcus placement of AIOLs may be needed [175][176][177].…”