PurposeThe purpose of this study was to determine an arcuate incision (AI) nomogram to treat astigmatism during femtosecond laser-assisted cataract surgery.MethodsThis is a retrospective, cohort study. Femtosecond laser (FSL)-assisted transepithelial AIs were created at a 9.0 mm optical zone, 80% depth, centered on the limbus. We modified the manual Donnenfeld limbal relaxing incision nomogram to 70% for with-the-rule (WTR), 80% for oblique (OBL), and 100% for against-the-rule (ATR) astigmatism. The correction index (CI) equaled AI-induced astigmatism/target-induced astigmatism. Measures included preoperative keratometric corneal cylinder (Pre Kcyl), postoperative Kcyl (Post Kcyl), and postoperative residual refractive astigmatism (Post RRA).ResultsMean Pre Kcyl and 1–2 months Post RRA in 161 eyes of 116 patients were 0.626±0.417 diopters (D) (range 0.5–2 D), and 0.495±0.400 D (range 0–1.5 D), respectively. Mean absolute astigmatic changes (Pre Kcyl–Post Kcyl) without accounting for axis change in the WTR, ATR, and OBL groups were 0.165±0.383 D (P<0.001), 0.374±0.536 D (P<0.001), and 0.253±0.416 D (P=0.02), respectively. Mean absolute astigmatic changes using RRA as the postoperative measurement (Pre Kcyl–Post RRA) without accounting for axis change were 0.440±0.461 D (P<0.001), 0.238±0.571 D (P<0.05), 0.154±0.450 (P=0.111) in WTR, ATR, and OBL groups, respectively. CIs for WTR, ATR, and OBL were 0.53, 1.01, and 0.95, respectively. There were no intraoperative or postoperative complications related to the AIs.ConclusionTransepithelial FSL-AIs using the modified Donnenfeld nomogram show potential for management of mild to moderate corneal astigmatism. An increase in the magnitude or reduction of the optical zone size for the treatment of WTR and ATR astigmatism for this nomogram may further improve refractive accuracy.

PurposeTo evaluate the collective user experience with an image-guided femtosecond laser (FSL) for cataract surgery in a high-volume, multi-surgeon, ambulatory surgical center.Subjects and methodsA detailed online survey was distributed to all surgeons in a single ambulatory surgical center who had performed cataract surgery using a FSL since its acquisition in December 2012. Information collected included the number of cases performed, typical surgical techniques and parameters, satisfaction with individual features of the laser (rated on a scale from 1=completely unsatisfied to 10=extremely satisfied) and commentary on ease of use and suggested improvements.ResultsSeventeen of 30 surgeons (56.7%) completed the survey, representing a case volume of 1,967 eyes. Fourteen surgeons (82.4%) felt they required ≤10 cases with the FSL to operate with the same safety and control as in standard phacoemulsification surgery. Satisfaction was highest for capsulotomies, lens fragmentation, lens softening, arcuate incisions and the graphic user interface (mean scores 9.4, 8.7, 8.7, 7.2 and 8.9, respectively). Preferred capsulotomy diameter was 4.8–5.2 mm (64.7% of respondents). About half (52.9%) of respondents centered the capsulotomy on the pupil and the other 47.1% centered the capsulotomy using optical coherence tomography. Most respondents (81.3%) preferred transepithelial arcuate incisions compared to intrastromal incisions. Satisfaction was lowest with FSL-created, main, clear corneal incisions and paracenteses (mean scores 4.4 and 4.2, respectively).ConclusionLaser-assisted cataract surgery has a short learning curve and a high rate of user satisfaction. Further software and hardware development is warranted to improve user satisfaction with peripheral and clear corneal incisions.

FLACS had a rate of unplanned vitrectomy comparable to conventional phacoemulsification. There was no statistically significant difference in unplanned vitrectomy rates between early and late FLACS cases suggesting a short learning curve. [J Refract Surg. 2018;34(9):610-614.].

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Our recent electrophysiological analysis of mouse retinal pigment epithelial (RPE) cells revealed that in the presence of 10 mM external thiocyanate (SCN−), voltage steps generated large transient currents whose time-dependent decay most likely results from the accumulation or depletion of SCN− intracellularly. In the present study, we investigated the effects of more physiologically relevant concentrations of this biologically active anion. In whole cell recordings of C57BL/6J mouse RPE cells, we found that, over the range of 50 to 500 µM SCN−, the amplitude of transient currents evoked by voltage steps was proportional to the extracellular SCN− concentration. Transient currents were also produced in RPE cells when the membrane potential was held constant and the external SCN− concentration was rapidly increased by pressure-ejecting 500 µM SCN− from a second pipette. Other results indicate that the time dependence of currents produced by both approaches results from a change in driving force due to intracellular SCN− accumulation or depletion. Finally, by applying fluorescence imaging and voltage-clamping techniques to BALB/c mouse RPE cells loaded with the anion-sensitive dye MQAE, we demonstrated that in the presence of 200 or 500 µM extracellular SCN−, depolarizing voltage steps increased the cytoplasmic SCN− concentration to an elevated steady state within several seconds. Collectively, these results indicate that, in the presence of physiological concentrations of SCN− outside the RPE, the conductance and permeability of the RPE cell membranes for SCN− are sufficiently large that SCN− rapidly approaches electrochemical equilibrium within the cytoplasm when the membrane voltage or external SCN− concentration is perturbed.