Accuracy of 11 intraocular lens calculation formulas in shallow anterior chamber eyes.

PURPOSE: To evaluate the performance of intraocular lens (IOL) calculation formulas and the effect of anterior chamber depth (ACD), axial length (AL) and lens thickness (LT) on the prediction accuracy in shallow ACD eyes. METHODS: This retrospective, consecutive case-series study included 648 eyes of 648 patients with an ACD < 3.0 mm who underwent phacoemulsification and IOL implantation. Eleven formulas were evaluated: Barrett Universal II (BUII), Emmetropia Verifying Optical (EVO) 2.0, Hill-Radial Basis Function (RBF) 3.0, Hoffer QST, Kane, Olsen, Pearl-DGS and traditional formulas (Haigis, Hoffer Q, Holladay 1 and SRK/T). Subgroup analysis was performed based on ACD, AL and LT. RESULTS: Overall, the Hoffer QST and Kane showed no systematic bias. The Kane, EVO 2.0, Hill-RBF 3.0 and Hoffer QST had relatively lower mean absolute error and higher percentages of prediction error within ±0.5 D. For the ACD of 2.5-3.0 mm and AL < 22.0 mm subgroup, the Pearl-DGS exhibited the lowest MAE (0.45 D) and MedAE (0.41 D). Most formulas had a significant myopic bias (-0.43 to -0.18 D, p < 0.05) in the LT < 4.3 mm subgroup and a significant hyperopic bias (0.09-0.29 D, p < 0.05) in the LT ≥ 5.1 mm subgroup. CONCLUSION: The Kane and Hoffer QST were recommended for shallow ACD eyes. In eyes with an ACD between 2.5 and 3.0 mm and a short AL, the Pearl-DGS showed excellent performance. Clinicians need to fine-tune the target refraction according to LT in shallow ACD eyes.

Is Astigmatism Correction Necessary for Patients With Cataract Who Have Corneal Astigmatism of Less Than 0.75 D?

PURPOSE: To investigate the proportion of patients with predicted refractive astigmatism (PRA) of 0.75 diopters (D) or greater and associated risk factors among cataract surgery candidates with low corneal astigmatism. METHODS: A retrospective cross-sectional study was conducted in Zhongshan Ophthalmic Center, Guangzhou, China. Patients with cataract who had preoperative simulated keratometric astigmatism of less than 0.75 D were recruited. The PRA was calculated by Barrett toric calculator using posterior corneal astigmatism (PCA) measured by the IOLMaster 700 (Carl Zeiss Meditec AG) and corneal surgically induced astigmatism (SIA). Two corneal incision locations (temporal [0°/180°], 135° incision) and varying magnitudes (0.10 to 0.60 D) were considered for SIA. Multiple logistic regression analysis was used to explore risk factors associated with PRA of 0.75 D or greater and build predictive model. Sensitivity analysis was performed using PRA threshold of 0.50 D. RESULTS: A total of 1,750 eyes from 1,750 patients were included (mean age: 60.14 ± 13.24 years, 42.91% male, 1,010 right eyes and 740 left eyes). The 135° incision (odds ratio [OR]: 17.86) and against-the-rule (ATR) astigmatism (OR: 37.55) are the major risk factors for PRA of 0.75 D or greater. Higher simulated keratometric astigmatism (OR: 2.03), larger PCA (OR: 1.64), and surgically induced astigmatism (OR: 1.29) also significantly increased the risk of PRA of 0.75 D or greater. Nomogram model were constructed with an area under curve of 0.90. CONCLUSIONS: For patients with corneal astigmatism of less than 0.75 D, temporal incision and measured PCA is preferred. Those patients with ATR astigmatism should be considered for astigmatism correction when using a 135° incision. [J Refract Surg. 2023;39(12):850-855.].

Electrochemical Decarboxylative Silylation of α,ß-Unsaturated Carboxylic Acids.

An electrochemical method for the decarboxylative silylation of α,ß-unsaturated carboxylic acids was developed. A variety of alkenylsilanes could be obtained in satisfactory yields and excellent selectivities under external oxidant- and metal-free conditions. Mechanistic studies showed that the formation of the silyl radical was mediated by NHPI, which produces the hydrogen atom transfer (HAT) reagent phthalimide N-oxyl (PINO) via multiple-site concerted proton-electron transfer (MS-CPET).

Recent advances in hydrothermal synthesis of facet-controlled CeO2-based nanomaterials.

CeO2-based nanomaterials have received tremendous attention due to their variety of applications. This paper is focused on the recent advances in facet-controlled CeO2-based nanomaterials by the hydrothermal method. CeO2-based nanomaterials with controllable size and exposed facets can be prepared by adjusting the reaction parameters. Moreover, doping and loading metals can improve the oxygen storage capacity (OSC) of CeO2 and its catalytic activity. Various research studies on catalytic applications such as CO oxidation, water-gas shift reaction (WGSR), decomposition of hydrocarbons, and photocatalytic reaction have been carried out to exhibit the high potential of facet-controlled CeO2 nanomaterials. This review will provide readers with various ideas for facet-controlled CeO2-based nanomaterials.

A method for isotope exchange kinetics in mineral-water system-an in-situ study on oxygen isotope exchange in Na2CO3-H2O system.

The experiments on the exchange reaction rate of the oxygen isotopes in the mineral-water system with initial conditions of 100 °C and 240 MPa, 100 °C and 924 MPa, 118 °C and 170 MPa are taken. The oxygen isotope 18O exchange reactions between aqueous C16O32- and H218O are mainly traced by measuring the Raman peak intensity of oxygen-containing elements (CO32-) in sodium carbonate solution. The inconsistent trends between the molar fraction and the concentration of C18O216O2- indicate oxygen isotope exchange between sodium carbonate and heavy water accompanied by dissolution and recrystallization between supersaturated sodium carbonate solution and solid sodium carbonate. In the heterogeneous experimental systems the order of oxygen isotope exchange reactions are more than 1 and the dynamics of oxygen isotope exchange conform to JMAK kinetics model with the nucleation and growth processes of sodium carbonate crystal.