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JCRS highlights chosen by Professor Thomas Kohnen, European Editor JCRS

Vol 43 Issue: 8 Month: August 2017

Thomas Kohnen

Posted: Wednesday, November 1, 2017

GLUED IOL AND ASTIGMATISM
Placement of a glued IOL produces less surgically induced astigmatism than seen after placement of a sutured scleral-fixated IOL, a prospective case study suggests. The study evaluated 16 eyes with aphakia and 15 with subluxated lenses over a mean follow-up of 12 months. There was a significant reduction in mean simulated K after surgery. The maximum K decreased significantly, from 44.85 ± 2.83D preoperatively to 44.47 ± 2.75D at six months. Mean surgically induced astigmatism was 1.0 ± 0.7D, ranging from 0.16 to 3.6D. The postoperative astigmatism analysis by the Alpins method was negative (−1.8), showing relative flattening after surgery. Multiple regression analysis found no association between postoperative vision and preoperative maximum K, postoperative simulated K, incision size and number of sutures. There was no correlation between the postoperative simulated K and incision position, sutures, and scleral flap position. The researchers conclude that glued IOLs can be implanted in eyes with preoperative maximum K ranging from 38.8 to 49.5D without significant loss of CDVA. DA Kumar et al., JCRS, “Corneal topography and keratometry changes after glued intraocular lens implantation”, Vol 43, No 8, p1062–1067.

YELLOW FILTERS AND STRAYLIGHT
How much do yellow filters influence retinal straylight? A prospective study looked at 56 right eyes of healthy volunteers using a colourless lens, followed by four other measurements using different yellow filters of different wavelengths. The use of yellow filters increased retinal straylight by a small but significant amount compared with the use of unfiltered light. This suggests that the visual comfort often experienced while wearing these filters is not associated with reduced straylight.
This would exclude glare reduction as a reason people might prefer them over spectacles with colourless plano lenses. A van Os et al., JCRS, “Influence of yellow filters on straylight measurements”, Vol 43, No 8, p1077–1080.

FEMTO-SCULPTING AN IOL
Investigators at the John A Moran Eye Center in the US evaluated the uveal and capsular biocompatibility of intraocular lens power adjustment by a femtosecond laser obtained through increased hydrophilicity of targeted areas within the optic, creating the ability to build a refractive-index shaping lens within an existing IOL.
Six rabbits had phacoemulsification with bilateral implantation of a commercially available hydrophobic acrylic IOL. The postoperative power adjustment was performed two weeks after implantation in one eye of each rabbit. Follow-up confirmed that consistent and precise power changes could be induced in the optic of commercially available IOLs in vivo by using a femtosecond laser to create a refractive-index shaping lens. The laser treatment of the IOLs was biocompatible. L Werner et al., JCRS, “Biocompatibility of intraocular lens power adjustment using a femtosecond laser in a rabbit model”, Vol 43, No 8, p1100-1106.