Intraoperative Aberrometry Versus Preoperative Biometry for IOL Power Selection After Radial Keratotomy: A Prospective Study.

PURPOSE: To compare the accuracy of Optiwave Refractive Analysis (ORA) intraoperative aberrometry (Alcon Laboratories, Inc., Fort Worth, TX) with preoperative biometry in predicting residual refractive error after cataract surgery in eyes that underwent radial keratotomy. METHODS: This was a prospective consecutive case series of patients with cataract and prior radial keratotomy. Each patient underwent a preoperative intraocular lens (IOL) power calculation using partial coherence interferometry (IOLMaster version 5; Carl Zeiss Meditec, Jena, Germany). For each eye, the Barrett True-K formula was used to select an IOL targeting emmetropia. Residual refractive error was predicted preoperatively using the SRK/T, Hoffer Q, Haigis, and Holladay formulas 1 and 2, and the ORA intraoperatively. Between 8 and 12 weeks after cataract extraction with IOL implantation, the postoperative refraction was compared with the preoperative and intraoperative predictions. RESULTS: The study comprised 52 eyes of 34 patients. The median absolute errors associated with each method were as follows: Barrett True-K formula (0.34), ORA aberrometer (0.53), and SRK/T (0.54), Hoffer Q (0.51), Haigis (0.54), SRK/T (0.57), and Holladay formulas 1 and 2 (0.44) (P = .08). The proportion of patients within ±0.50 diopters of the predicted error was 63.5%, 48.1%, 44.2%, 48.1%, 53.8%, 36.5%, and 57.7%, respectively (P = .03). No statistically significant difference was observed in the number of eyes with hyperopic outcomes (P = .68). CONCLUSIONS: In eyes with prior radial keratotomy surgery, the ORA aberrometer performance was similar to the Barrett True-K formula and all of the other established formulas, with no significant difference between median absolute error and mean absolute error. The Barrett True-K formula produced significantly more eyes within ±0.50 diopters than the SRK/T, Hoffer Q, and Holladay 1 formulas. [J Refract Surg. 2019;35(10):656-661.].

Architecture evaluation of the main clear corneal incisions in femtosecond laser-assisted cataract surgery by optical coherence tomography imaging.

PURPOSE: To assess the stability and reliability of femtosecond laser-assisted cataract surgery (FLACS) incisions design and dimensions using anterior segment optical coherence tomography (AS-OCT) imaging. SETTING: Renato Ambrósio Ophthalmologic Study Center from Hospital Oftalmológico de Brasília, Brasília, Brazil. DESIGN: Prospective nonrandomized controlled case series. METHODS: Eyes undergoing FLACS with triplanar main temporal clear corneal incision (CCI) were evaluated at the end of the case. Eyes that required any incision hydration, surgical complications or lacked follow-up were excluded. The AS-OCT was performed after femtosecond delivery; at the end of the case; at 1 day and at 30 days after surgery. Data of pachymetry, endothelial and epithelial gaps, Descemet detachment and CCI architecture were compared. RESULTS: Eleven eyes from 11 patients completed follow-up. Corneal thickness was statistically different between after femtosecond delivery and the end of the case (P-value <0.05), but without difference compared to 30 days evaluation. There was an increase of Descemet detachments (P-value <0.05) and endothelial gaps (P-value =0.0133) at the end of the case compared to post-femtosecond delivery. As for the architecture of the CCI, significant difference was found between the parameters of entry angle and exit angle measured with AS-OCT and the programmed. CONCLUSION: The AS-OCT was capable of visualizing changes in the cornea at the CCI. Despite the stress caused by manipulation, results indicated good stability of incision and reproducibility of tunnel length. SYNOPSIS: Difference of corneal thickness at the CCI between after femtosecond and after phacoemulsification measurements (P-value <0.05), with increase of endothelial gaps (P-value =0.0133) and Descemet detachments (P-value <0.05).