Long‐term clinical audit of glistenings in Alcon Acrysof intra‐ocular lenses with and without yellow chromophore

Abstract

Glistenings in intra-ocular lenses have been noted by clinical observation at the slit lamp in over 90% of Alcon Acrysof lenses on follow up 15 to 20 years after insertion in a cohort of 31 cases. A recent audit conducted by RANZCO showed glistenings still occurred in lenses produced after a decade long improvement in manufacturing techniques undertaken by Alcon. A two surgeon clinical audit was conducted to determine the incidence of glistenings in Alcon IOLs of different ages, models and chromophore content. All patients with Alcon IOLs presenting at routine follow up were audited sequentially by surgeon BDS (68 SA60AT lenses) and surgeon PH (all other lenses). Glistenings were graded using the criteria outlined by Werner et al with the addition of a Grade 4 density level for those worse than Grade 3. Implantations occurred between 1998 and 2016. Four IOL models were assessed (17 three-piece MA series, 74 SA60AT, 57 SN60AT, 153 SN60WF—including torics). Among the 284 lenses audited 35% of clear lenses but 66% of yellow lenses showed glistenings. Considering glistenings graded as 2 or greater, which may be more significant clinically, 2% of clear lenses and 35% of yellow lenses were affected (Figure 1). Glistening density was not strongly associated with duration in the Eye (Figure 1). In the subset of chromophore free three-piece lenses (N = 17) with a long mean time in the eye of 17 years, only seven showed grade one glistenings and there were no higher grades. In order to address the question whether differences in glistenings density were IOL model related or chromophore related, a comparison of SA60AT chromophore-free lenses with SN60AT and SN60WF yellow lenses with similar times in situ was undertaken. This analysis was achieved by excluding 79 of the SN60WF lenses with the shortest times in situ. This resulted in three groups of IOLs of similar size and with similar times in situ (Table 1). A pairwise Wilcoxon test showed a statistically significant difference between the IOLs with the chromophore and those without (P < .0001). However, the chromophore lenses SN60AT and SN60WF were not significantly different from each other. This audit suggests lenses containing chromophore were more likely to show glistenings and have higher density of glistenings than chromophore free lenses of the same material. Glistenings did not differ significantly between lens models unless there was a difference in chromophore status. There have been many glistenings related publications over the last 20 years, but our literature search did not find papers with long-term follow up which specifically address the significance of the chromophore. These results suggest that the chromophore is strongly associated with glistening formation. A possible methodologic weakness in this study is that BDS contributed most of the clear lenses (68 of the 74 SA60AT cases) but all other cases came from PH. However, both surgeons had very similar surgical techniques and operated at the same day surgery. They also used a standardized photographic classification (Werner et al) which has been utilized in many publications. Although concordance in grading between BDS and PH has not been specifically tested, given the very large differences found, a genuine influence of the chromophore on glistening formation remains highly likely. Given that two major recent reviews have not found the addition of a blue light blocking chromophore to be clinically helpful, surgeons may find this audit's conclusion pertinent when choosing an IOL for implantation in their patients. Surgeons wishing to look at their own cases in collaboration with colleagues can contact cpd@ranzco.edu for a link