B-scan biometry improves accuracy in clear lens extraction

BIRMINGHAM, England — B-scan biometry can help locate the macula in highly myopic patients scheduled for clear lens extraction, according to clinicians here. The method can provide a better means of calculating IOL power than A-scan measurement in these patients.

“Because the eyes of these patients are not spherical and have staphyloma, it can be very difficult to locate the macula. What you're using the B-scan for is to accurately locate the macula,” said Peter Good, PhD, of the Birmingham and Midland Eye Center.

A-scan biometry used on these types of eyes tended to result in inaccurate measurements, Dr. Good said. In his study, Dr. Good compared measurements from A- and B-scan biometry. The B-scan was highly effective in measuring the axial length in long myopic eyes, Dr. Good said.

“With the B-scan, we are up to a 98% success rate in getting patients within 1 D of their desired postoperative refraction,” Dr. Good said.

Their success with this technique over the past 2 years has led them to use B-scan routinely in evaluation of patients with long eyes. The device can also be used to assess IOL power in preoperative evaluation for cataracts in myopic eyes.

For more information about Dr. Good’s study, read the October 15 issue of Ocular Surgery News.