Abstract
Purpose::
Identify and examine the chemical structure of intraocular debris found after injection of the AR-40 lens during cataract surgery using scanning electron microscopy (SEM) and x-ray microanalysis (XRM).
Methods::
SEM and XRM were used to evaluate two samples of debris located posterior to a pcIOL and in the capsular bag following injection of AR-40 IOLs (AMO Inc., Santa Ana, CA). SEM and XRM also were used to evaluate crystalline lens from these two patients removed at the time of surgery. SEM and XRM were used to evaluate samples of Viscoat® and Provisc® (Alcon, Inc., Ft. Worth, TX). Samples were placed directly on double sided carbon adhesive tape on aluminum stubs and coated with carbon by high vacuum evaporation, and were examined in a Cambridge S-200 SEM (Carl Zeiss SMT, Inc. Thornwood, NY) at 20kV. The x-ray spectra were made using a Kevex 7000 energy dispersive x-ray spectrometer (Thermo Electron Corp. Waltham, MA). The microscopic structure and chemical composition of the samples were compared.
Results::
SEM showed that the viscoelastic had an irregular surface with multiple peaks and valleys. The crystalline lens material was much smoother with shallow linear surface striations. The debris had an irregular undulating surface that appeared similar to the surface of the viscoelastic. XRM showed that the lens material was composed mainly of sulfur and calcium (2.3 keV and 3.7 keV, respectively), Viscoat® and Provisc® were both composed of silicone (1.8 keV), and the debris was composed mainly of silicone (1.8 keV) with smaller amounts of chlorine, titanium, aluminum, magnesium, iron, zinc, phosphorus, potassium, sulfur and calcium detected in the different samples.
Conclusions::
The intraocular debris is consistent with viscoelastic. The chemical composition of the debris was similar but not identical to viscoelastic. Therefore, the debris may represent chemically or structurally altered viscoelastic that has been rendered insoluble. Although the origin of the altered viscoelastic is unknown, it likely comes from viscoelastic left behind on the lens injector. Following lens injection, the injector is autoclaved. This could result in chemical and structural alteration to the viscoelastic. When the injector is next used, the altered viscoelastic is injected along with the normal viscoelastic into the eye.
Keywords: cataract • intraocular lens • microscopy: electron microscopy