Thomas Kohnen
Published: Wednesday, February 1, 2017
TRANSEPI-PRK OR FEMTO-LASIK FOR MYOPIA?
Transepithelial photorefractive keratectomy (PRK) treats refractive errors by superimposing a defined epithelial thickness profile with a corneal aspheric ablation profile. Femtosecond-assisted LASIK procedures involve laser-assisted stromal flap creation and subsequent stromal ablation to compensate for the refractive error. Researchers compared one-year outcomes with the two procedures in a retrospective analysis of 196 patients. Visual outcomes were equivalent for both treatment approaches at one year. However, patients treated with transepithelial PRK had longer recovery times with more variation in outcomes than in the femto-LASIK patient group.
M Luger et al, JCRS, “Myopia correction with transepithelial photorefractive keratectomy versus femtosecond−assisted laser in situ keratomileusis: One-year case-matched analysis”, Volume 42, Issue 11, 1579-1587.
TORIC IOL IMPLANTATION, RESIDUAL ASTIGMATISM
Residual astigmatism after toric intraocular lens (IOL) implantation reportedly ranges from 0.00 to 2.25D depending on the preoperative astigmatism. This could be because either the IOL is not in the appropriate orientation to correct the astigmatism, or the IOL has too much or too little cylinder power, or both could occur. In an effort to gain a better understanding of suboptimum outcomes with toric IOLs, investigators used an online toric back-calculator to analyse 12,812 cases with a mean postoperative refractive astigmatism of 1.89 dioptres. They found that refractive astigmatism was significantly higher with higher IOL cylinder power (P<.01), but was not different by IOL manufacturer. Some 90% of IOLs were not at the ideal orientation, despite 30% being at the preoperative calculated orientation. Misalignment showed a directional bias for some IOLs but not for others.
BA Kramer et al, JCRS, “Residual astigmatism after toric intraocular lens implantation: Analysis of data from an online toric intraocular lens back-calculator”, Volume 42, Issue 11, 1595-1601.
MEASURING NEGATIVE DYSPHOTOPSIA
Negative dysphotopsia continues to be a concern following cataract surgery with IOL implantation. A two-part study compared the extension of peripheral visual fields in phakic and pseudophakic patients and evaluated whether Goldmann kinetic perimetry can be used as an objective measure of negative dysphotopsia. The study confirmed that modern cataract surgery was not associated with a reduction in the visual field in pseudophakic patients. Moreover, kinetic perimetry proved to be an effective measurement tool, showing constriction of the visual field or relative scotoma in patients with negative dysphotopsia.
NY Makhotkina et al, JCRS, "Objective evaluation of negative dysphotopsia with Goldmann kinetic perimetry", Volume 42, Issue 11, 1626–1633.
Tags: Journal of Cataract and Refractive Surgery
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