Abstract
Purpose:
Feasibility study on IOL power calculation based on ocular parameters measured by means of a novel Purkinje imaging technique combined with an optical coherence method.
Methods:
Thirty eyes scheduled for cataract surgery were enrolled into this prospective feasibility study. The study was approved by the local ethic committee and the Irish Medicine Board. Patients were consented in writing before enrolled into the clinical investigation. All eyes underwent pupil dilation to at least 5 mm pupil diameter before the eyes were measured with a standard of care (SOC) corneal tomography (Oculyzer, WaveLight, Erlangen, Germany) and ocular biometry (Biograph, WaveLight, Erlangen, Germany). After that the eyes were measured by means of a prototype ocular biometry device that consists of a Purkinje imaging technique combined with an optical coherence method (ClearSight Innovation Ltd, Dublin, Ireland). The Purkinje imaging technique allows measurements of the corneal anterior and posterior surfaces as well as the lens anterior and poster surfaces. The optical coherence method provides measurements of corneal thickness, anterior chamber depth, lens thickness and axial length. The obtained ocular parameters from each were statistically compared by means of regression analysis, bland altman plots and paired descriptive statistics, where applicable.
Results:
All correlation coefficients (r) for the ocular parameter: anterior radius of curvatures, posterior radius of curvatures, anterior chamber depth, lens thickness, axial length were found to be r > 0.9 compared with the SOC devices. No significant differences for all mean values were found between the new device and the SOC devices. The SOC ocular biometry device did not provide any measurements of the posterior corneal surface, and anterior and posterior lens. The SOC ocular tomography device provided only anterior and posterior corneal surface measurements and corneal thickness.
Conclusions:
The results of this initial prospective study demonstrate the feasibility of the new ocular biometry system to provide comparable ocular parameters with SOC devices. However, SOC devices do not provide information about the lens geometry. In contrast, the combined measurements of the new device allow a complete reconstruction of the eye parameter suitable for optical ray tracing to calculate intraocular lens power.