OBJECTIVE: To present a new method of dynamic Purkinje-metry and to verify it by comparison with a commercially available anterior segment optical coherence tomography CASIA2.
METHODS: A dynamic Purkinje-meter with a movable fixation target was assembled. A coaxial circular pattern formed by infrared LEDs was projected onto the eye and evoked Purkinje images (1st, 3rd, 4th = P1, P3, P4). The measurement was performed on 29 eyes with an implanted toric IOL (intraocular lens), under mydriatic conditions, with reference to the visual axis. The IOL tilt was calculated from the position of a fixation target at the moment of P3 and P4 superposition. The IOL decentration was determined based on the relative position of P1 during on-axis fixation and of P3 and P4 superposition during off-axis fixation. A custom-developed software was used for distance measurements. Using CASIA2, the IOL position was fully calculated by the device.
RESULTS: The mean absolute difference between CASIA2 and Purkinje-meter values was 0.6° ± 0.4° for the tilt magnitude and 10° ± 10° for the tilt direction, and 0.11 mm ± 0.08 mm for the decentration magnitude and 16° ± 14° for the decentration direction. There was no statistically significant difference between the values determined by the two methods for the tilt and decentration direction. The differences were statistically significant for the tilt and decentration magnitude.
CONCLUSIONS: The values of IOL tilt and decentration direction are similar for both devices. The values of IOL tilt and decentration magnitude measured by Purkinje-meter are higher than those from CASIA2, but overall, they correspond to the values presented in other published studies.

OBJECTIVE: Predict intraocular lens position after cataract surgery using the IOL Master 700 and explore the associated ocular parameters compared with the results obtained from the anterior segment analysis system (Sirius, CSO Inc, Florence, Italy).
METHODS: A total of 98 patients (106 eyes) were included in the retrospective study. The postoperative intraocular lens position was obtained using the IOL Master 700 and measured using Adobe Illustrator software. Correlation analysis and linear regression analysis were applied to study the correlation between the actual position of the postoperative intraocular lens (ALP) and the ocular parameters. In addition, Bland-Altman consistency analysis was used to compare the consistency between any two among the predicted intraocular lens position (ALPi) obtained using IOL Master 700 biometry, the predicted artificial lens position (ALPs) calculated using the anterior segment analysis system, or the ALP.
RESULTS: Ocular parameters, including preoperative anterior chamber depth, lens thickness, axial length, white-to-white, and postoperative refractive error were all correlated with ALP after cataract surgery (P < 0.05) using univariate analysis. However, in multivariate linear regression, only the first three variables were correlated with ALP. Compared with the equation obtained by the anterior segment analysis, the equation from IOL Master 700 biometry provided a better fit. The results of the consistency analysis showed that ALP, ALPi, and ALPs were in good agreement.
CONCLUSIONS: IOL Master 700 biometry can help predict intraocular lens position after surgery, and its accuracy is better than that provided by the anterior segment analysis system.

OBJECTIVE: To analyze changes in surgically induced corneal astigmatism and articial intraocular lens (IOL) stability over time following cataract surgery. To compare the interchangeability of measurements between an automatic keratorefractometer (AKRM) and a biometer.
METHODS: In this prospective observational study, the above-mentioned parameters were collected from 25 eyes (25 subjects) on the first day, first week, first and third month after uncomplicated cataract surgery. We used IOL-induced astigmatism (difference between refractometry and keratometry) as an indirect indicator of IOL stability change. We used the Blant-Altman method to analyze consistency between devices.
RESULTS: At the above time points, surgically induced astigmatism (SIA) decreased as follows: 0.65 D; 0.62 D; 0.60 D and 0.41 D (in the first day, week, month and third month respectively). Astigmatism induced by changes of the position of the IOL varied as follows: 0.88 D; 0.59 D; 0.44 D and 0.49 D. Changes in both parameters were statistically significant (p0.05).
CONCLUSIONS: Both surgically induced astigmatism and astigmatism induced by IOL decreased over time, in which both changes were statistically significant. The decrease in SIA was most pronounced between the first and third month after surgery. For IOL-induced astigmatism, the greatest decrease was within the first month after surgery. The differences in measurement between the biometer and AKRM were statistically insignificant, but the clinical interchangeability between the given methods is questionable, especially with regard to measurement of the astigmatism angle.

OBJECTIVE: This study aims to quantify and identify risk factors for intraocular lens (IOL) tilt and decentration early after surgery using Scheimpflug imaging.
METHODS: We prospectively included 268 eyes of 253 patients who underwent uneventful cataract surgery and one-piece IOL implantation using a superior or temporal approach. Scheimpflug imaging was used to evaluate the tilt and decentration of IOLs at 1 week, 1 month, and 3 months postoperatively. Differences in IOL tilt and decentration between the approaches were examined. Correlations of age and axial length with the magnitudes of IOL decentration and tilt were also examined.
RESULTS: In total, 139 right and 129 left eyes were included. IOL displacement averaged 150 μm upward and 150 μm to the nasal side of the pupil. Over 50% of the eyes were tilted upward and approximately 90% to the temporal side. The surgical approach was significantly associated with horizontal decentration in both eyes, but significantly associated with only vertical decentration in the right eye 1 week postoperatively. In the left eyes, IOLs were shifted to the nasal side in 57.1% and 36.8% of the eyes that received the temporal and the superior approach, respectively, compared with 75.8% and 50% in the right eyes. The differences were significant only at 1-week follow-up (p = 0.035 and p = 0.003, respectively). Age or axial length was not associated with IOL tilt or decentration in either eye.
CONCLUSIONS: Scheimpflug imaging can be used as a quantitative tool to evaluate IOL position. The incision site affected the IOL position, this finding was significant at 1 week postoperatively only.