Intraindividual Correlation Of Crystalline Lens Decentration And Tilt With Postoperative Intraocular Lens Decentration And Tilt With A Monofocal Hydrophobic Acrylic Intraocular Lens

To assess the development of postoperative decentration and tilt of a new hydrophobic acrylic intraocular lens (IOL) in relation to preoperative crystalline lens characteristics.

One-hundred-twenty-two eyes of 65 patients received  an aspheric, monofocal, hydrophobic acrylic IOL Nanex NC1-SP (Hoya Surgical Optics, Chromos, Singapore) with a total diameter of 13.0 mm. Decentration and tilt of the crystalline lens was assessed 1 to 2 weeks prior to surgery. Decentration and tilt of the pseudophakic lens was assessed one week (1w) and 6 months (6m) after surgery by anterior segment OCT Casia 2 (Tomey, Nagoya, Japan). Factors influencing postoperative decentration and tilt, such as preoperative anterior chamber depth or axial length, were assessed.

Absolute decentration and tilt were 0.21±0.11mm and 5.7±1.6° preoperatively, 0.21±0.13mm and 5.5±1.4° after 1w, and 0.24±0.14mm and 5.6±1.5° after 6m. Mean difference in decentration and tilt of the crystalline lens to the IOL after 6m was 0.21±0.12mm and 1.39±0.98°. Mean difference in decentration from preoperative to 1w was 0.16±0.09mm and from 1w to 6m 0.12±0.09mm. Mean difference in tilt from preoperative to 1w was 1.17±0.69°and from 1w to 6m 1.14±0.87°. Preoperative anterior chamber depth was negatively correlated with tilt from preoperative to postoperative after 6 months (r=-0.23;p=0.02). Preoperative tilt of the crystalline lens was positively correlated with IOL tilt after 1w (r=0.88;p<0.01) and after 6m (r=0.79;p<0.01).

Postoperative tilt and decentration values of the Nanex IOL proved to be very low. The postoperative tilt of the IOL was strongly dependent on the preoperative tilt. IOLs implanted in eyes with shallow preoperative anterior chambers tended to tilt more than those with deep anterior chambers. This might be due to the narrower anatomical conditions.