ABSTRACT
AIM: To provide guidance for more accurate measurement of axial length(AL)of difficult measuring eyes by comparing the differences in the AL of the patient's difficult measuring eye with three methods of the sitting position, supine position A-scan and Lenstar 900(Lenstar, LS900). METHODS: Clinical case-control study. We selected 102 cases(102 eyes)including cataract patients with combined silicone oil filled, vitreous hemorrhage or retinal detachment and patients with dislocation of the lens or IOL in Zhengzhou Second Hospital from May 2019 to September 2020. AL were measured using LS900 and A-scan on sitting position and supine position respectively, and the results of the three methods were statistically analyzed.RESULTS: The detection rates of LS900 and A-scan axial measurement were 83% and 100% respectively. Three methods of A scan in sitting position, supine position and LS900 to measure the overall AL, silicone oil group, lens dislocation group and vitreous hemorrhage group, the differences were statistically significant(P<0.001), The mean values of AL measured by overall A-scan, supine positions of silicone oil group, supine position of lens dislocation group and vitreous hemorrhage group were statistically significant differences with LS900 measurement(all P<0.05), while there was no statistical difference between the results of the overall sitting position and the difficult measuring eye groups' sitting position compared with the LS900 measurement of AL. The three measurements showed good consistency within the 95% consistency range, but the result of A-scan on sitting position was closer to LS900.CONCLUSION: Changing the conventional decubitus position to the sitting position can improve the accuracy of the measurement results and provide clinicians with more reliable guidance for the treatment of patients with difficult measuring eyes of A-scan axial measurement, especially in diseases with altered ocular structure.
ABSTRACT
PURPOSE: The axial length measurement is an important variable in calculating the intraocular lens (IOL) power in cataract surgery. In this study, the effects of the implantable collamer lens (ICL) on the axial length measurement were investigated. METHODS: The axial lengths of 141 eyes of 76 highly myopic patients were measured before ICL implantation and 1 month postoperatively using applanation A-scan ultrasound. RESULTS: The measured axial lengths before ICL implantation and 1 month after the surgery were 28.03 +/- 1.91 mm and 28.08 +/- 1.86 mm respectively, with a statistically significant difference of 0.05 mm (p = 0.036). These 2 values showed a high correlation (R2 = 0.9829, p < 0.0001). CONCLUSIONS: Even though the axial length after ICL implantation significantly increased, the 0.05 mm change was too small to influence the determination of the IOL diopters in cataract surgery. Therefore, ICL implantation history may be reflected when measuring the axial length for the IOL power calculation in cataract surgery, but the axial length measured immediately before the cataract surgery may be used to calculate the IOL power regardless of the ICL implantation history.
Subject(s)
Humans , Cataract , General Surgery , History , Lenses, IntraocularABSTRACT
PURPOSE: To evaluate the clinical efficacy and complications of intraocular lens (IOL) exchange. METHODS: A review of medical records was performed for 52 eyes that had undergone an IOL exchange due to IOL opacification. Surgical complications and their incidences were analyzed. The mean best corrected visual acuity (BCVA) after the IOL exchange was compared with the mean pre-exchange BCVA and with the mean BCVA after the initial IOL implantation. Prediction error of refraction and biometric data obtained for the IOL exchange were, if available, compared with those obtained for the initial IOL implantation. The prediction error for the IOL exchange, calculated from the biometric data obtained before the IOL exchange, was compared with that calculated from the measurements obtained before the initial IOL implantation. RESULTS: The overall complication rates were low and no serious complications were found. The mean BCVA improved significantly after the IOL exchange and was not significantly different from that obtained after the initial IOL implantation. However, the refractive prediction for the IOL exchange was not as good as it was for the initial IOL implantation, which was thought to be related with difficulties in axial length (AL) measurements. Biometric data taken before the initial IOL implantation was associated with a significantly better refractive prediction than those taken before the IOL exchange. CONCLUSIONS: IOL exchange was both efficacious and safe for visual recovery. However, IOL exchange was related with increased difficulty of predicting postoperative refraction; difficulties in AL measurements are the suggested cause.