FEB 19, 2015
By Adam J. Gess, MD
Cataract/Anterior Segment
This interesting prospective pilot study found that anterior chamber depth (ACD) measured after capsular tension ring (CTR) implantation using intraoperative OCT was a more accurate way of calculating lens power.
The results suggest that we may someday put a CTR in all patients and use intraoperative OCT ACD measurement to choose a lens in real time.
The authors sought to determine if postoperative refraction could be predicted more accurately using aphakic ACD measured intraoperatively with OCT for IOL power calculation formulas.
They used a prototype operating microscope with an integrated continuous OCT device to measure the anterior lens capsule position after CTR implantation in 70 eyes of 70 patients. Optical biometry (IOLMaster 500) and ACMaster measurements were performed before surgery, and autorefraction and subjective refraction three months after surgery.
They implanted an IOL as previously planned based on the standard IOLMaster formulas. Then they compared prediction of postoperative refractive outcome using conventional IOL power calculation formulas with a new model incorporating intraoperatively measured ACD.
The next steps could be to automate taking intraoperative measurements and use these capsule position measurements in fourth-generation formulas or ray tracing using the real anatomical IOL position instead of a fictitious effective lens position.