Higher-Order Aberrations And Light Scattering In Primary Intraocular-Lens Calcification

Intraocular lens (IOL) calcification can only be treated by removing the clouded lens. Since explantation bears the risk of complications, it is often deferred until the patient finds the symptoms intolerable. Visual acuity may be only minimally affected, though. In this study, we assessed the impact of primary opacification on optical quality

David J. Apple Center for Vision Research, Department of Ophthalmology, University of Heidelberg, Germany.

We analyzed ten IOLs (Oculentis GmbH) that hat had been sent to the David J. Apple Laboratory by explanting surgeons. In all cases, primary opacification was reported as the only reason for explantation. Photographs of the IOL explants were taken using a light microscope. Wavefront aberrations were obtained with a SHSOphthalmic device (Optocraft GmbH), which features a Hartmann-Shack sensor. We detected light scattering with a C-Quant instrument (Oculus GmbH) and expressed it as a logarithm of the straylight parameter (logs). The Root-Mean-Square (RMS) of higher-order aberrations was compared. The effect of calcification on image quality was assessed through the Strehl ratio (SR).

At 2 mm, 3 mm, and 4 mm, the mean RMS (±standard deviation) was 0.033 μm (±0.026 μm), 0.044 μm (±0.027 μm), and 0.087μm (±0.049 μm), respectively. The mean SR value was 0.81 (±0.15) at 3 mm, with four IOLs showing a nearly diffraction-limited performance. By contrast, increased straylight was found in all opacified IOLs with a mean value of 2.11 ±0.32 logs at 3 mm.

We demonstrated that primary opacification induces higher-order aberrations. However, the RMS remained low, which resulted only in a slight reduction of the optical quality. On the other hand, we found a severe straylight elevation, which may result in photic phenomena, such as glare and subjective complaints, despite good visual acuity.