Abstract
Purpose::
To demonstrate a benefit in using partial coherence interferometer (ZEISS IOLMASTER) compared to traditional immersion a-scan in a multisurgeon center with a predominantly African-American patient population.
Methods::
Charts of 162 patients (244 procedures) at an academic center who had undergone uncomplicated phacoemulsion and intracapsular IOL implantation were reviewed. All scans were done by the same technician, who has been certified on both machines by the manufacturers. Software was not changed during the time period of the study. Patients were randomly chosen from a database of procedures from the years 2000 to 2005 from surgeries performed by attending physicians and residents. Records were divided by pre-operative measurement device. More women than men were included (102 to 60). Average age of patients was 71 years (range=33-96, SD=12.5 years) at first surgery, and 71.05 years (35-96, SD=13.0) for the 82 patients that underwent a second procedure. Seventy-one percent of the study patients were African-American, and 29% were Caucasian. Most of the surgeries utilized the same lens (ALCON SA60AT, n=202). Patients who had undergone laser or prior ocular surgery or with ocular pathology expected to limit post-operative best corrected visual acuity were excluded. Reviewer was blinded as to type of scan used. Main outcomes reviewed were improvement in visual acuity and difference between predicted versus postoperative spherical equivalent. Subgroup analysis was completed to identify if there was a training advantage with the IOLmaster from the first year of use to the second year. Use of the SRK/T versus Halliday algorithms was examined to see if outcomes could have been improved by a different protocol.
Results::
Improvement in visual acuity was better in the Partial Coherence Interferometer (PCI) group by 0.108 logMAR (P=0.027). Mean difference from predicted to post-operative spherical equivalent was less in the IOLmaster group by 0.19 D (IOLmaster=0.25D, ultrasound=0.44D, P=0.037). There was no training benefit noted from one year to the next on the IOLmaster for either outcome. No benefit was seen between using Halliday versus SRK/T on either machine.
Conclusions::
Outcomes with the PCI were significantly better than with traditional ultrasound in an academic setting. We attribute this to less of a physician factor being necessary in deciding which lens to use, although the racial background of the patients suggests that corneal thickness may play a role.
Keywords: intraocular lens • refractive surgery: phakic IOL • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)