Comparison Of Tilt And Decentration Of Two Aspheric Intraocular Lenses Implantation After Phacoemulsification

Objective To observe and measure position of two kinds of aspheric intraocular lenses by ultrasonic biomicroscope(UBM), and discuss effect the orientation of IOL in capsule bag may have on tile and decentration.Method Thirty-seven patients45eyes underwent cataract surgery were distributed to two groups randomly. Group A,17patients22eyes, was implanted with four-haptic Akreos AO IOL(Bausch&Lomb) while group B,20patients23eyes, was impended with two-haptic ZCBOO IOL(Abbott Medical Optics). Eyes in group B were distributed to two sub-groups randomly. IOLs was implanted in capsule bag horizontally in group B1(10patients11eyes) and Vertically in group B2(10patients12eyes).All groups underwent standard cataract surgeries, recorded diameter of capsulotomy. One month postoperatively, Best-corrected visual acuity (BCVA) assessment, slit lamp examination, refraction and UBM evaluation were performed. Tilt and decentration were measured horizontally and Vertically, and total tilt and decentration were calculated by geometry method.Results No statistical diference was found in BCVA or diameter of capsuloyomy between two group A and group B. The mean ACD of group A and group B was3.86±0.31mm and4.14±0.31mm, respectively, which showed statistically significant differences (p<0.05). Horizontal decentration,vertical decentration and total decentration of group A was0.15±0.09mm,0.15±0.12mm and0.22± 0.12mm respectively,while it was0.22±0.21mm,0.14±0.15mm and0.29+0.22mm for group B. Horizontal tilt, vertical tilt and total tilt of group A was0.63±0.62°,0.89±0.85°and1.22±0.76°.while it was1.36±1.48°,1.46±1.62°and2.21±1.97°for group B. No statistically significance was found in tilt and decentration between group A and group B, no matter horizontally or Vertically or totally. Horizontal decentration,vertical decentration and total decentration of group B1was0.24±0.28mm,0.15±0.15mm and0.31±0.28mm respectively, while it was0.20±0.13mm,0.13±0.16mm and0.28±0.14mm for group B2. Horizontal tilt, vertical tilt and total tilt of group B1was1.01±1.18°,1.81±1.95°and2.29±2.05°,while it was1.64±1.71°,1.14±1.26°and2.14±1.99°for group B2. No statistically significance was found in tilt and decentration horizontally or vertically between the two group B1and B2.Conclusion Two-haptic IOL shows no difference in tilt and decentration postoperatively with four-haptic IOL. The IOL orientation in capsule bag appeared to have no effect on IOL tilt and decentration. Combine with geometry calculation, UBM can measure IOL tilt and decentration more precisely.