Evaluation of intraoperative aphakic eye axial length measurements using swept-source OCT.

PURPOSE: To evaluate intraoperative aphakic eye axial length (AL) measurements using swept-source optical coherence tomography (SS-OCT). SETTING: Hanusch Hospital, Vienna, Austria. DESIGN: Prospective single-center study. METHODS: Patients scheduled for cataract surgery were measured using SS-OCT (IOLMaster 700, Carl Zeiss Meditec AG) to assess the AL. Intraoperatively (intra-OP), SS-OCT measurements were performed with a prototype device (IOLMaster 700 connected to an OPMI Lumera 700 microscope, CZM) at the beginning of cataract surgery furthermore of the aphakic eye and 2 months after surgery. RESULTS: 106 patients were included. Of the 59 eyes of 59 patients, the phakic median AL preoperatively and intra-OP was 23.61 mm ± 0.96 (standard deviation [SD]) and 23.51 mm ± 0.96 (SD), respectively. The absolute median difference was 0.028 ± 0.02 (SD) (P = .049). Median phakic AL intra-OP vs 2 months postoperatively (post-OP) was 23.51 mm ± 0.97 (SD) vs 23.49 mm ± 0.95 (SD). The absolute median difference was 0.049 ± 0.04 (SD) (P = .000). Median AL intra-OP aphakic vs 2 months post-OP pseudophakic was 23.42 mm ± 0.97 (SD) vs 23.42 mm ± 0.97 (SD), respectively. Absolute median difference was 0.038 ± 0.04 (SD) (P = .379). CONCLUSIONS: Intra-OP, SS-OCT technology of the phakic and aphakic eye shows excellent comparability to preoperative and postoperative measurements. This technique allows AL measurements with high precision in cases in which preoperative biometric measurements are not possible.

Intraoperative optical coherence tomography measurements of aphakic eyes to predict postoperative position of 2 intraocular lens designs.

PURPOSE: To evaluate intraoperative anterior chamber depth (ACD) measurements of the aphakic eye to predict the postoperative ACD and compare 2 intraocular lens (IOL) designs. SETTING: Hanusch Hospital, Vienna, Austria. DESIGN: Prospective study. METHODS: In this prospective study, patients scheduled for cataract surgery received a plate-haptic IOL (Asphina, Carl Zeiss Meditec AG) or an open-loop haptic IOL (ZCB00, Johnson & Johnson). Preoperatively, optical biometry (IOLMaster 700, CZM, or Lenstar, Haag-Streit) was performed. Intraoperatively, a prototype setup was used to perform time-domain OCT scans of the anterior eye segment (Visante connected to OPMI Lumera 200, both CZM). The intraoperative ACD was measured and used to predict the postoperative IOL position. Optical biometry and subjective refraction and autorefraction (RM 8800, Topcon) were performed 2 months postoperatively. RESULTS: The study comprised 203 eyes of 203 patients. A partial least-square regression model for ACD generated 2 months postoperatively showed that the predictive power of the intraoperative ACD (0.48) was highest followed by the axial eye length (0.45) and then the preoperatively measured ACD (0.30). These findings were confirmed in a bootstrapping model. Regression models combining the preoperative ACD and intraoperative ACD resulted in further significant improvement. CONCLUSIONS: Intraoperative ACD measurements predicted the postoperative position of open-loop IOLs and plate-haptic IOLs better than preoperative ACD measurements. Combining preoperative and intraoperative ACD measurements further improved the prediction.

Using continuous intraoperative optical coherence tomography to classify swirling lens fragments during cataract surgery and to predict their impact on corneal endothelial cell damage.

PURPOSE: To quantify and classify swirling lens fragments during cataract surgery and record their impact on the corneal endothelium using continuous intraoperative optical coherence tomography (OCT). SETTING: Vienna Institute for Ocular Surgery, Hanusch Hospital, Vienna, Austria. DESIGN: Prospective case series. METHODS: Patients scheduled for cataract surgery without other ophthalmologic comorbidities were included. During surgery, continuous OCT recordings were performed to measure and score swirling lens fragments that came into contact with the corneal endothelium. Endothelial cell density (ECD) was measured preoperatively and 1 month postoperatively. In addition, the central corneal thickness and aqueous flare were measured preoperatively and 1 hour, 1 day, and 1 month postoperatively. RESULTS: Continuous intraoperative OCT video recordings showed 104 swirling lens fragments in 40 eyes that came into contact with the corneal endothelium. A mean of 2.6 lens fragments (range 0 to 6) that came into contact were observed per eye. Small fragments and fragments touching the center of the endothelium had a significantly greater effect on postoperative ECD than other fragment parameters. The predictive power of the fragment score on ECD was found to be moderate (r(2) = 0.6). CONCLUSIONS: Small swirling lens fragments touching the center of the corneal endothelium had a significant influence on ECD. With the newly developed fragment score, it was possible to predict the operative endothelial cell loss. FINANCIAL DISCLOSURE: None of the authors has a financial or proprietary interest in any material or method mentioned.

Using continuous intraoperative optical coherence tomography measurements of the aphakic eye for intraocular lens power calculation.

BACKGROUND/AIMS: To include intraoperative measurements of the anterior lens capsule of the aphakic eye into the intraocular lens power calculation (IPC) process and to compare the refractive outcome with conventional IPC formulae. METHODS: In this prospective study, a prototype operating microscope with an integrated continuous optical coherence tomography (OCT) device (Visante attached to OPMI VISU 200, Carl Zeiss Meditec AG, Germany) was used to measure the anterior lens capsule position after implanting a capsular tension ring (CTR). Optical biometry (intraocular lens (IOL) Master 500) and ACMaster measurements (Carl Zeiss Meditec AG, Germany) were performed before surgery. Autorefraction and subjective refraction were performed 3 months after surgery. Conventional IPC formulae were compared with a new intraoperatively measured anterior chamber depth (ACD) (ACDIntraOP) partial least squares regression (PLSR) model for prediction of the postoperative refractive outcome. RESULTS: In total, 70 eyes of 70 patients were included. Mean axial eye length (AL) was 23.3 mm (range: 20.6-29.5 mm). Predictive power of the intraoperative measurements was found to be slightly better compared to conventional IOL power calculations. Refractive error dependency on AL for Holladay I, HofferQ, SRK/T, Haigis and ACDintraOP PLSR was r(2)=-0.42 (p<0.0001), r(2)=-0.5 (p<0.0001), r(2)=-0.34 (p=0.010), r(2)=-0.28 (p=0.049) and r(2)<0.001 (p=0.866), respectively, CONCLUSIONS: ACDIntraOP measurements help to better predict the refractive outcome and could be useful, if implemented in fourth-generation IPC formulae.

Predicting the postoperative intraocular lens position using continuous intraoperative optical coherence tomography measurements.

PURPOSE: The aim of this study was to assess, if measuring the position of the lens capsule intraoperatively with a continuous intraoperative optical coherence tomography (OCT) device could be useful to improve the prediction of the intraocular lens (IOL) position. METHODS: This prospective study included patients who were scheduled for cataract surgery. A prototype operating microscope with an integrated continuous OCT device was used to measure the anterior and posterior lens capsule position at different time points during cataract surgery. In all cases, a capsular tension ring (CTR) was used to tauten the lens capsule. Partial coherence interferometry was used to measure anterior chamber depth (ACD) immediately before, and 1 hour and 3 months postoperatively. Partial least squares regression (PLSR) was used to assess the influence of different pre- and intraoperatively measured parameters. RESULTS: In total, 70 eyes of 70 patients were included. Mean axial eye length was 23.6 mm (range, 20.6 mm-30.8 mm), mean used IOL power was 22.2 diopters (D; range, 6.0 D-31.5 D). PLSR showed that the anterior lens capsule measured after removing the crystalline lens and after implanting a CTR was a significantly better predictor for the postoperative ACD compared with preoperative ACD measurements. CONCLUSIONS: The main problem of IOL power calculation, the prediction of the IOL position after surgery, could possibly be reduced by using intraoperative lens capsule measurements instead of preoperative ACD measurements. (ClinicalTrials.gov number, NCT01867541.).