Eyeworld

73 EW RESIDENTS June 2015 In the greater than 25 micron glistening group, contrast VA was found to improve with a larger per- cent area to size ratio. Additionally, both BCVA and contrast VA with glare were found to improve with an increased number of glistenings per unit area. The authors felt the findings in the >25 micron group were likely false positives. We agree that this may result from a threshold for statistical significance that might be expected to provide some false positive correlations with multiple comparisons or could be due to either a study inadequately powered to elucidate the true relationship among these factors or a relation- ship among the measured parame- ters that is incompletely understood. In order to avoid confounding effects on visual outcomes, the au- thors applied strict exclusion criteria for subject selection, including a BCVA of 20/20-1 or better, no visual complaints, and the absence of ocu- lar comorbidities. This led to a clear Long-term observation of surface light scattering in foldable acrylic intraocular lens Kazunori Miyata, MD, PhD, Masato Honbou, COT, Ryohei Nejima, MD, Keiichiro Minami, PhD, Shiro Amano, MD, PhD J Cataract Refract Surg (June) 2015;41:Article in press Purpose: To observe time-course changes in surface light scattering of the AcrySof intraocular lenses (IOLs) over 6 years postoperatively and the influence on visual function. Setting: Miyata Eye Hospital, Miyakonojo, Miyazaki, Japan Design: Retrospective comparative case series Methods: Clinical records of 24 eyes that received AcrySof IOLs (14 eyes) or other IOLs (10 eyes) were examined. Postoperative examinations including light scattering on the anterior surface of IOL, best corrected distance visual acuity (DCVA), and contrast sensitivity had been performed at 1 month and 3 years postoperatively. In the present study, the same examinations were performed for extended postoperative period. Time-course changes in surface light scattering and visual function were thus analyzed. Results: The mean postoperative periods at the last examinations were 8.4±1.0 years (range; 6.5–10 years). Surface light scattering of the AcrySof IOL group increased even after 3 years at the rate of 12.02 computer compatible tapes per year, whereas it did not increase in the other IOL group. Change in DCVA remained unchanged at 3 and over 6 years postop in both groups. There was no difference in contrast sensitivity between the two groups over 6 years postop. Conclusions: Surface light scattering increased even after 3 years postoperatively in the AcrySof IOLs, however, this did not affect the visual function. The impact of intraocular lens glistening size on visual quality Bradley S. Henriksen, BS, Krista Kinard, MD, Randall J. Olson, MD J Cataract Refract Surg (June) 2015;41:Article in press Purpose: To determine if intraocular glistenings impact light scatter and visual function. Setting: John A. Moran Eye Center Laboratories, University of Utah, Salt Lake City, Utah Design: Retrospective cohort study Methods: 79 pseudophakic patients with visual acuity no worse than logMAR 0.02 and no ocular pathology were enrolled. All had received a single-piece high-refractive index acrylic intraocular lens (IOL). All IOLs were photographed, and glistenings were analyzed for size and density. Outcome measures included logMAR corrected distance visual acuity (CDVA), mesopic 10% contrast logMAR CDVA with and without glare, and straylight determination (C-Quant log). Results: All patients had glistenings within two diameter groups: 6–25 microns (μ) and >25 μ. Linear regression for the non-stratified group was significant for IOL vs. glistening size, and contrast VA with glare. Linear regression for the 6–25 μ group was significant for a measure of severity index (% area) vs. C-Quant, % area/size vs. C-Quant, IOL age vs. BCVA, IOL age vs. contrast visual acuity (VA), and IOL age vs. contrast VA with glare. Linear regression for the >25 μ group was significant for IOL age vs. glistening size and % area/size vs. contrast VA, and density vs. BCVA and contrast VA with glare. Conclusions: Glistening % area, at a key size, correlates with random light scatter. IOL age likely has impact on glistening size and visual parameters. continued on page 74 finding that the 2 AcrySof lenses exhibit increasing surface light scatter with IOL age and concluded that this trend continued through the additional follow-up period. In- creasing surface light scatter was not seen in the Abbott Medical Optics lens group. The authors evaluated the visual effects of surface light scatter by looking at the change in DCVA and contrast acuity in the same patients over time and found no correlation with light scatter or either visual outcome. This longitu- dinal approach to evaluating change in vision with change in light scatter over time is a more pow- erful comparison than evaluating patients with IOLs of different ages, as has been done in other studies. Publication of a power calculation with this information could bol- ster this conclusion in spite of the limited sample size. An additional factor that the authors may consider investigating is the effect of glare on CDVA, as this may enhance the visual consequence of surface light scatter. Finally, as the authors note, this extended period of follow-up still represents only a fraction of the lifetime of an IOL in the human eye, and the trend toward increased sur- face light scatter showed no signs of stabilization at the last time point; thus, the possibility remains that visual function may ultimately be affected by continued progression of surface light scatter. A retrospective cohort study by Henriksen, Kinard, and Olsen 6 evaluated 79 eyes to elucidate the effect of glistening size and density in hydrophobic acrylic IOLs on light scatter and visual function. Based on the prior work of DeHoog and Doraiswamy, 7 they hypothesized that smaller glistenings would lead to increased light scatter and therefore greater visual effects. In accordance with their hypothesis, they concluded that for lenses with glistenings ranging between 6–25 microns in size, the ratio of percent area occupied by glistenings to glis- tening size was positively correlated with greater light scatter. This correlation was of borderline sta- tistical significance (P=0.047) and was not detected in the group with glistenings greater than 25 microns. While this could represent a subtle but true difference between the 2 size groups, it seems likely it is due to either a false positive in the former or inadequate sample size to detect a correlation in the latter. Other notable results include positive correlations between IOL age and glistening size as well as IOL age and worsening contrast VA with glare for the entire group (not stratified by glistening size). Based on the initial result that smaller glis- tenings cause more surface scatter, one might expect that VA would improve as glistenings grow larger with age. As noted by the authors, both the percent area occupied by glistenings and glistening size may play a role in light scatter and visual effects. The rate of change and the relative impact of each of these factors may explain why VA worsens with IOL age in spite of increased glistening size.

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