Eyeworld

159 EW RESIDENTS April 2016 measurements affect postoperative lens positioning; however, many other factors do as well, such as lens selection, surgeon technique, Overall, the authors concluded that the effective lens position was difficult to predict due to many fac- tors, including zonular fiber location and insertion, fibrosis of the cap- sular bag, and the innate elasticity properties of the zonules in individ- ual eyes. The strengths of this study include a prospective study design with consecutive patients. The study's follow-up of 4–6 weeks is adequate given the fact that the IOL position is likely stable by this time postoperatively. Another strength is the fact that all patients were examined by a single examiner both pre- and postoperatively, which reduces variability of measurements that may be caused by differences in machine operation and place- ment of calipers when measuring depth and angles on the Visante machine. The use of a single sur- geon could be viewed as either a strength or a weakness; however, it seems appropriate to eliminate the additional variability caused by surgeon techniques when trying to establish relationships. Ultimately, a surgeon factor should be used in IOL formulas to correct for individual variation. The greatest limitation of the study is the lack of data regarding lens density and/or type of cataracts. The density of the cataract is known to change the ACD and angle depth, as denser cataracts have greater lens thickness. This causes greater narrowing of the angle and ACD compared to a less dense cataract. Therefore, removal of a dense cata- ract alone will lead to a significant change in the ACD and angle depth, regardless of axial length. Further- more, increased lens thickness can lead to more anterior bowing of the iris, affecting the degree to which it moves posteriorly after IOL place- ment. It would be ideal to know the lens thickness and take this factor into account when interpreting the relative changes in position. Similarly, even though the authors presented demographic data, they did not comment on the fact that eyes with longer axial length had a lower median age and much larger age range. Presumably, younger patients have thinner lenses than older patients, and this alone may account for differences of the mea- sured variables between the group with long eyes and the groups with normal and short eyes. Therefore, it would be helpful for the authors to present additional data regarding the cataracts, including lens thick- ness and density. The topic presented is com- plex due to the multiple variables involved in predicting postopera- tive lens position, iris position, and ACD. Axial length and preoperative and lens position before and after and long axial length" Tel. 1 888-519-5375 ads@oculususa.com www.oculususa.com The gold standard, now with axial length measurement – versatile, profitable, indispensable! Once again, the Pentacam® defines the "measure of all things." The AXL version, featuring integrated optical biometry, makes it a comprehensive, indispensable instrument for cataract surgery. As a full-scale system, the Pentacam® AXL also provides for safe and swift IOL calculation – even in difficult cases. Visit www.pentacamaxl.com to learn more. Now Available! The OCULUS Pentacam ® AXL Always an Axial Length Ahead facebook.com/OCULUSusa continued on page 160

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