A comparative study on calculation of intraocular lens power using different formulas between IOLMaster 700 and IOLMaster 500 in cataract eyes / 中华实验眼科杂志

Objective:To compare the accuracy of IOLMaster 700 and IOLMaster 500 in intraocular lens (IOL) power calculation.Methods:A cross-sectional study was conducted.Two hundred and sixty-two eyes of 262 patients who underwent phacoemulsification combined with IOL implantation at the Eye Hospital of Wenzhou Medical University from November 2018 to November 2019 were enrolled.Preoperative biometry for cataract surgery was performed using IOLMaster 700 and IOLMaster 500.IOL power was calculated through the built-in formulas, Haigis, Holladay Ⅰ, Hoffer Q and SRK/T of the two devices.The difference in IOL power calculation between the two devices was analyzed through the prediction error of IOL power calculation using different formulas across different axial length (AL) ranges.This study complied with the Declaration of Helsinki.The study protocol was approved by the Ethics Committee of the Eye Hospital of Wenzhou Medical University (No.2020-038-K-33). Written informed consent was obtained from each patient before the surgery.Results:There was no significant difference in mean absolute error (MAE) between IOLMaster 700 and IOLMaster 500 using Haigis, Hoffer Q and SRK/T over the entire AL range (all at P >0.05). The MAE of IOLMaster 500 was 0.47 (0.24, 0.90) D, which was significantly lower than 0.50 (0.28, 0.99) D of IOLMaster 700 using Holladay Ⅰ formula ( Z=-3.120, P=0.002). When AL was <22.0 mm and ≥24.5 mm-<26.0 mm, there was no significant difference in MAE between the two devices using the four formulas (all at P >0.05). When AL was ≥22.0 mm-24.5 mm, there was no significant difference in the MAE between the two devices using Haigis, Hoffer Q and SRK/T (all at P >0.05), but 0.42 (0.18, 0.75) D from IOLMaster 500 was smaller than 0.45 (0.25, 0.79) D from IOLMaster 700 using Holladay Ⅰ, showing a statistically significant difference ( Z=-3.487, P <0.001). But the difference was negligible and therefore was of no clinical significance.When AL was ≥26.0 mm, there was no statistically significant difference in the MAE between the two devices using Haigis, Holladay Ⅰ and SRK/T, but 0.66 (0.38, 1.00) D from IOLMaster 500 was significantly smaller than 0.98 (0.62, 1.32) D from IOLMaster 700 using Hoffer Q ( Z=-3.046, P=0.002). Conclusions:The refractive prediction accuracy of IOLMaster 700 and IOLMaster 500 using Haigis, Hoffer Q and SRK/T is similar over the entire AL range.For patient with long AL, the IOL calculation from IOLMaster 700 using Hoffer Q is significantly larger than that from IOLMaster 500, which requires extra caution in clinical practice.The accuracy of IOLMaster 700 and IOLMaster 500 for IOL prediction is very similar.

Relationship of Posterior Capsular Opacification and Capsular Bend Type Investigation Based on Swept-source Optical Coherence Tomography.

Purpose: To investigate the relationship between capsular bend type and posterior capsule opacification (PCO) at a three-dimensional (3D) level using high-speed swept-source optical coherence tomography (SS-OCT).Methods: This was a retrospective study. A total of 99 eyes that underwent standard cataract surgery with phacoemulsification 2 years ago were analyzed. Standard SS-OCT radial scanning was performed in all eyes and the obtained photos were used for morphological observations of the capsular bend-IOL complex, the adhesion of posterior capsule to the IOL optic, and the position of the anterior capsulorhexis. Digital retroillumination photographs were taken of the posterior capsule of each eye to evaluate PCO (scoring and area).Results: In terms of the PCO score and area, there was no statistical difference between eyes with complete and incomplete adhesion of posterior capsule to IOL (both P > .05), whereas the partial overlap group showed a statistical difference greater than the total overlap group (P < .05). There were two types of capsular bends, completed adhesion (CA) and incomplete adhesion (IA). IA was divided into funnel adhesion (IA-F), parallel adhesion (IA-P), and detached adhesion (IA-D). The incomplete adhesion index (IAI) varied between eyes and ranged from 0 to 1. The PCO score and area in the high IAI group (higher than 0.50) were significantly greater than the low IAI group (< 0.50) (P < .05). In addition, the PCO score and area were significantly higher in the cohort with at least one IA-D capsular bend in six districts to the group that did not have IA-D capsular bend (P < .05).Conclusions: Complete or incomplete adhesion of the posterior capsule to the IOL optic may not be necessary for the development of PCO. Our study suggests that capsular bend type may be used as an index to predict PCO.

Three-Dimensional Morphology Study of Capsule in Pseudophakic Eyes with High-Speed Swept-Source Optical Coherence Tomography.

PURPOSE: To study the capsule morphology in pseudophakic eyes on the three-dimensional level using high-speed swept-source optical coherence tomography (SSOCT). METHODS: This study collected patients with age-related cataract and divided them into two groups according to the anterior capsule and intraocular lens (IOL) optic relationship: total anterior capsule overlap (360°, Group-T) and partial anterior capsule overlap (<360°, Group-P). One standard SSOCT radial scanning was performed in all eyes at 1 day, 1 week, 1 month, and 3 months postoperatively. RESULTS: Thirty-two eyes from 25 patients were enrolled in the Group-T and 17 eyes from 13 patients in the Group-P. No eyes achieved complete adhesion between IOL optic and posterior capsule at 1 day after the surgery. However, the rate of complete adhesion was low (15/49, 30.6%) even at 3 months postoperatively and there was no statistically difference between Group-T and Group-P (21.9% vs. 47.1%, P > 0.05). At 1 day, 1 week, 1 month, and 3 months after the surgery, the capsule bend index (CBI) in the Group-T was 0.02 ± 0.09, 1.35 ± 1.48, 3.60 ± 0.54, and 3.88 ± 0.19, respectively. CBI rises linearly during the first month and the rise goes stable relatively with the great reduction of standard deviation in the following 2 months (All P < 0.05). The anterior capsule opening area and diameter were both reduced in the first month, and then they both became stable. CONCLUSIONS: With square-edge IOL, posterior capsule opacification risk is still high in most eyes at 3 months postoperatively for the complete adhesion of posterior capsule and IOL was only achieved in 30.6% eyes. IOL-in-bag may be driven by the significant capsule bag changes especially in the first month postoperatively.

Application of functional visual acuity in ophthalmology / 中华实验眼科杂志

Since functional visual acuity(FVA) was put foward,it is regraded as a kind of functional vision examination which can well reflect an individual' s performance in relation to certain daily activities involving visual tasks,the concept and the measurement is updating with the progress of technology.This examination was first applied in the patients with dry eye,and now it's applicable to detect and evaluate the refractive error,cataract,retinal pathological changes,or the eyedrops' use,and it can provide evidences for the early dignosis or the effects of thraphy of some ocular disease.In this paper,an introduction of the concept,methods and system of FVA,the clinical application of FVA in dry eye,refractive error,cataract,and in patients with fundus diseases and the research progress were reviewed.