Laboratory evaluation of higher-order aberrations and light scattering in explanted opacified intraocular lenses

Background Intraocular lens (IOL) calcification is a serious condition that 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. Usually, as the IOL opacifies, visual acuity is minimally affected early on. In this study, we assessed the impact of IOL opacification on optical quality. Methods We analyzed ten opacified explanted IOLs (Oculentis GmbH). Wavefront aberrations were obtained with a SHSOphthalmic device (Optocraft GmbH), which features a Hartmann-Shack sensor. The root mean square (RMS) of higher-order aberrations (HOAs) was compared. The effect of calcification on image quality was assessed through the Strehl ratio (SR). We detected light scattering with a C-Quant (Oculus GmbH) and expressed it as a straylight parameter. Results At 2 mm, 3 mm and 4 mm, the mean RMS (+/- standard deviation) was 0.033 mu m (+/- 0.026 mu m), 0.044 mu m (+/- 0.027), and 0.087 mu m (+/- 0.049), respectively. The mean SR value was 0.81 +/- 0.15 at 3 mm, with four IOLs showing a nearly diffraction-limited performance, but in two explants, opacification precluded reliable measurements. Increased straylight was found in all opacified IOLs with a mean value of 150.2 +/- 56.3 deg(2)/sr at 3 mm. Conclusions We demonstrated that IOL opacification induces HOAs. However, the RMS remained low, which resulted only in a slight reduction of the SR-derived optical quality. On the other hand, we found a severe straylight elevation in the opacified lenses, which may result in dysphotopsia, such as glare, and subjective complaints, despite good visual acuity.

Automated summary

The study found that IOL calcification can induce higher-order aberrations, but the RMS value remains low, resulting in only a slight decrease in optical quality derived from SR. However, a significant increase in straylight was observed in opacified lenses, which may lead to subjective complaints such as glare, despite good visual acuity.