In-vitro evaluation of straylight from intraocular lenses with laboratory-induced glistenings

Session Details

Session Title: Pseudophakic IOLs: Monofocal/Accommodative

Session Date/Time: Tuesday 13/09/2016 | 16:30-18:00

Paper Time: 17:00

Venue: Hall C2

First Author: : G.Łabuz THE NETHERLANDS

Co Author(s): :    N. Reus   T. Van Den Berg                 

Abstract Details

Purpose:

Although it is widely realized that glistenings must have the disadvantageous effect of light scattering, functional effects have not unequivocally been established. Clinical reports have not shown a clear association between glistenings and visual acuity nor contrast sensitivity. However, it may not be logical to study these visual function parameters. Instead one would expect that an increased amount of scattered light from microvacuoles may result in increased straylight and thus disability glare in pseudophakic patients. The current study evaluates the impact of glistenings on disability glare by means of the straylight parameter.

Setting:

Laboratory setting, Rotterdam Ophthalmic Institute, Rotterdam, the Netherlands

Methods:

Six SN60WF and 2 SN60AT IOLs (both from Alcon Inc.) were subjected to the temperature fluctuation test. The IOLs were put in bottles filled with balanced salt solution and placed in a laboratory stove. They were heated multiple times at different temperatures to gradually increase the number of glistenings. The samples were analyzed upon cooling at room temperature. Microscopic images of the IOLs were obtained and analyzed to quantify the area and number of microvacuoles. Straylight was measured using a commercial straylight meter (C-Quant, Oculus) adapted for in-vitro analysis of scattering from IOLs. The outcome was compared with Mie theory.

Results:

The logarithm of the straylight parameter (log[s]) measured at 7 and 2.5 degrees was 1.19 ±0.45 log(s) (from 0.23 to 1.78 log[s]) and 1.26 ±0.48 log(s) (from 0.17 to 1.89 log[s]) respectively. The mean frontal surface per glistening ±SD (range) was 32.48 ±14.63 μm2 (21.80 to 78.90 μm2). A proportional relation (R2=0.95) was established between straylight and the portion of the IOL surface covered by glistenings. At higher straylight values proportionality is lost.

Conclusions:

The effect of glistenings on straylight has a precise association with the size and number of the microvacuoles present in the IOL bulk. A good correspondence with Mie theory was found. A large number of microvacuoles is needed to result in significant straylight elevation. The results of the current study may advance knowledge on the potential for straylight elevation and its clinical significance due to glistenings formation in IOLs.

Financial Disclosure:

NONE