Lens Thickness Measurements in Eyes With Myopia Vary With Different Devices

Lens thickness measurements may demonstrate variability when measured with biometry and intraoperative optical coherence tomography (iOCT) in eyes with myopia, according to research published in Eye. These differences are clinically significant and may have implications for calculating intraocular lens (IOL) power in individuals undergoing cataract surgery, the report suggests. 

Researchers enrolled 173 patients (eyes, 251;  47.4% women, mean age, 63.7 years) who were set to undergo cataract surgery and recorded anterior chamber depth (ACD) and lens thickness measurements that were obtained using both biometry and iOCT. The team included eyes with hyperopia (n=44), myopia (n=60), and emmetropia (n=147) and performed general and subgroup analyses to examine agreement between the 2 devices.

The ACT measurements obtained with biometry were shorter than those obtained with iOCT when considering all refractive errors (mean difference, −0.026 mm; P =.001), but these differences failed to demonstrate clinical relevance. A subgroup analysis according to refractive error revealed statistically significant differences in ACD measurements only in eyes with emmetropia (P =.003). 

Lens thickness measurements, however, showed statistically significant variability among all eyes included in the investigation (P <.001) and in subgroup analyses for all refractive errors (P <.001 for all). These lens thickness measurements were only clinically significant in eyes with myopia, evidenced by a mean difference of −0.0903 mm (95% CI, −0.1118 to −0.0689; P <.001) between biometry and iOCT devices.

“The expectations on the quality and refractive results of cataract surgeries are rising steadily. This leads to the continuous development and improvement of more precise measuring techniques of the anterior eye parameters…,” the researchers explain. “In consideration of the fact that in clinical practice, mostly ‘only’ one device will be used, it is useful to be aware of possible measurement differences.”

Study limitations include a retrospective nature, the use of different patient positioning for obtaining ACD and lens thickness measurements, and an inability to determine the reproducibility of measurements.