Clinical Outcomes of Posterior Chamber Phakic IOL Sized Using Ultrasound Biomicroscopy and Anterior Segment Optical Coherence Tomography
Narrative Responses:
Purpose
To study position of the posterior chamber phakic intraocular lens (PIOL) with total size selected using ultrasound biomicroscopy (UBM) and new algorithm based on anterior segment optical coherence tomography (AS-OCT) in patients with high myopia.
Methods
Retrospective analysis of data from 31 patients (58 eyes) who underwent surgical correction of high myopia with posterior chamber PIOL ICM V4 (STAAR Surgical). Ciliary sulcus diameter was used to select the PIOL size and was assessed with either UBM (straight measurement on 3 scans) or AS-OCT (using the new algorithm to discover and measure the distance between peripheral iris pigment endings). Two study groups were formed: UBM group (15 patients, 29 eyes) and AS-OCT group (16 patients, 29 eyes). In each case preoperative and postoperative spherical equivalents (SE) were measured with autorefractometry; PIOL vault was analyzed using AS-OCT.
Results
Preoperative spherical equivalent (SE) values in UBM and AS-OCT groups were -12.05±4.22D and -16.55±3.65D respectively (P<0.02), while postoperative SE measurements were -1.20±0.97D and -0.95±1.21D respectively (P>0.05).
Mean PIOL vault in the UBM group 0.36±0.28mm in comparison with 0.53±0.18mm in AS-OCT group (p<0.05). Optimal PIOL vault (0.35 to 0.7mm) was found in 8 and 16 eyes in UBM and AS-OCT groups respectively. Excessive PIOL vault (over 0.7mm) — in 5 and 7 eyes respectively. Poor vault (under 0.35mm) — in 16 and 6 eyes respectively (P<0.01). We observed the PIOL-lens contact in 8 cases in UBM group only.
Conclusion
New algorithm of ciliary sulcus diameter assessment based on AS-OCT allows selecting PIOL size precisely, which was demonstrated by clinical results.