Loss of optical media transperency reduces accuracy in clinical practice
Wavefront aberrometry (WA) offers promising applications in ophthalmology and can provide valuable information in previously underresearched conditions including hyperopia and cataract-related reduced visual acuity (VA). In clinical settings, WA is frequently used to assess patients presenting for refractive surgery, and previous studies have demonstrated a high level of accuracy of WA measurements in comparison to those of manifest refraction (MR) and autorefraction. However, the subjects of these studies have primarily been young, myopic and well-sighted patients, while in clinical practice the majority of patients presenting for cataract surgery are of advanced age, with ametropia and reduced VA.
As a patient's VA can be affected when WA is used as a basis for surgical treatment of pathological conditions (particularly if the measurements are less accurate in specific patient populations), Dr Stephan Linke, Dr Jan Hülle (University Medical Center HamburgEppendorf, Germany) and colleagues decided to conduct a study to evaluate the accuracy of WA in comparison to MR in an older population awaiting cataract surgery.1 The trial was intended to help the team determine if previous study results can be replicated in clinical practice and to establish which factors, if any, affect the accuracy of the refractive values as measured by WA.
Assessing the eyes
"We had anticipated that WA would measure the same refractive values as MR, but that potential measurement differences between the devices would be explained either by the refractive state - hyperopia versus myopia - or by age. We also thought that the only impact of cataract on the results would be that more progressed forms of cataract would lead to more exaggerated differences between measurements taken on the separate devices," explained Dr Hülle. "However, some of the results we actually achieved were surprising, and were in fact contrary to previously published conclusions."