Jan Willem van der Linden

Straylight measurements in laser in situ keratomileusis and laser-assisted subepithelial keratectomy for myopia

PURPOSE: To compare straylight values before and 3 months after laser in situ keratomileusis (LASIK) and laser‐assisted subepithelial keratectomy (LASEK) and to analyze the causes of any change. SETTING: Private refractive surgery clinic, Driebergen, The Netherlands. METHODS: Straylight was measured before and after LASIK or LASEK with a C‐Quant straylight meter; values were recorded as the straylight parameter log(s). Main outcome measures were the difference between postoperative and preoperative straylight values and factors causing a difference between the values. RESULTS: The study evaluated 102 eyes having LASIK and 137 eyes having LASEK. On average, there was significant improvement in straylight values postoperatively in both groups. The mean decrease was −0.016 log(s) in the LASIK group and −0.026 log(s) in the LASEK group. Nonparametric testing (sign test) showed that the improvement in straylight was statistically significant in more than 50% of eyes in both groups. Straylight improved in 62 eyes in the LASIK group (P<.001) and 78 eyes in the LASEK group (P<.02) and deteriorated in 35 eyes and 58 eyes, respectively. There was an increase in straylight in 17 eyes (7.1%). Clinical correlations were found in some eyes that had increased postoperative straylight values. CONCLUSION: On average, straylight values 3 months after LASIK and LASEK were slightly decreased from baseline values. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned. Additional disclosures are found in the footnotes.

Effect of Nd:YAG laser capsulotomy on refraction in multifocal apodized diffractive pseudophakia.

PURPOSE To evaluate the effect on refraction of neodymium:YAG (Nd:YAG) laser posterior capsulotomy for posterior capsule opacification (PCO), and to evaluate the correlation between automated and subjective refraction in multifocal apodized diffractive pseudophakia. METHODS A retrospective study of 75 pseudophakic eyes (50 patients) with multifocal apodized diffractive pseudophakia, treated for PCO with Nd:YAG laser posterior capsulotomy, was performed. Pre- and postintervention values of refractive and visual parameters were compared. The outcomes of autorefraction and subjective refraction were also compared. RESULTS Uncorrected and corrected distance visual acuity improved significantly after Nd:YAG capsulotomy (P<.001). No significant changes were noted in defocus equivalent, astigmatic power vectors J(0) and J(45), and overall blurring strength in subjective refraction and autorefraction. Spherical equivalent changed significantly in autorefraction (P=.008), but not in subjective refraction. Autorefraction and subjective refraction were highly correlated in spherical equivalent, defocus equivalent, and blurring strength (r(2)>0.59). In approximately 7% of eyes, a change of more than 0.50 diopters in spherical equivalent in subjective refraction occurred. CONCLUSIONS In most cases, Nd:YAG laser capsulotomy in patients with multifocal pseudophakia did not result in a change in refraction. However, 7% of eyes experienced a significant change in subjective refraction. Autorefraction correlated well with subjective refraction in apodized diffractive multifocal IOLs.

Straylight measurements before and after removal of epithelial ingrowth

In 3 eyes with epithelial ingrowth after laser in situ keratomileusis, straylight was measured before and after the ingrowth was removed. In 2 eyes of 1 patient, epithelial ingrowth reached the pupillary axis. Straylight decreased (improved) significantly after ingrowth removal: a 3.6-fold decrease in the right eye and a 10-fold decrease in the left eye. The uncorrected distance visual acuity (UDVA) improved from 0.25 (20/80) in both eyes to 1.0 (20/20) and 0.8 (20/25), respectively. In 1 eye of another patient, from which epithelial ingrowth was removed to prevent flap melting and distortion, the pupillary opening was not obscured and no significant change in straylight was found. The UDVA improved from 0.32 (20/60) to 1.0 (20/20) after the ingrowth was removed. An increase in straylight can be a significant complication of epithelial ingrowth. After the interlamellar space is cleared, the improvement in straylight is several factors larger than the gain in UDVA.

Autorefraction versus subjective refraction in a radially asymmetric multifocal intraocular lens

To evaluate whether the automated refraction (AR) correlates with subjective manifest (MR) refraction in eyes implanted with radially asymmetric multifocal intraocular lens (IOLs).

Straylight Measurements in Two Different Apodized Diffractive Multifocal Intraocular Lenses

PURPOSE To evaluate differences in straylight between eyes implanted with a hydrophilic multifocal IOL (Seelens MF; Hanita Lenses, Hanita, Israel) and a hydrophobic multifocal IOL (SN6AD1; Alcon Laboratories, Inc., Fort Worth, TX). METHODS In a prospective cohort study, routinely obtained straylight measurements (C-Quant; Oculus Optikgeräte, Wetzlar, Germany) 3 months after standard phacoemulsification for either cataract or refractive lens procedures were compared. Patients were implanted with either the SeeLens MF IOL or the SN6AD1 IOL. Postoperative straylight values, visual acuity, and refractive outcomes were compared. RESULTS The SeeLens MF IOL was implanted in 84 eyes and the SN6AD1 IOL in 79 eyes. The difference in straylight was 0.08 (P = .01), with the SeeLens MF IOL having less straylight. Postoperative CDVA was logMAR -0.03 ± 0.06 in the SeeLens MF group, and logMAR -0.02 ± 0.08 in the SN6AD1 group. Mean postoperative refraction was +0.01 ± 0.43 and +0.06 ± 0.35 D, respectively. CONCLUSIONS The Seelens MF IOL showed a stray-light of log(s) 0.08 lower than the SN6AD1 IOL. In terms of spherical equivalent and visual acuity the lenses performed equally. More study will aid in understanding the causes and clinical impact of this difference.