Post-Yag Capsulotomy Pits And Their Impact On Intraocular Lens Function

Posterior capsule opacification (PCO) is the most common complication of cataract surgery. A Nd:YAG laser capsulotomy is a standard treatment for PCO. However, misfocusing the laser can cause laser pits. Since laser pits were first observed, their potential impact on quality of vision has been debated. Thus, this study investigates the effects of laser pits in a series of explanted IOLs that had been removed for unrelated reasons to determine their potential effect on visual quality.

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

Explanted IOLs with laser pits (n=10) and without laser pits (n=8) were included. First, light microscopy evaluation of the included IOLs was performed. The modulation transfer function (MTF), which has a strong correlation with clinical visual acuity, and straylight – a parameter associated with glare phenomena - were used to assess how laser pits affect the optical performance of the IOLs. Straylight was assessed using a clinical C-Quant straylight meter and an optical bench setup to precisely quantify light scattering, and thus, glare effects from the explanted IOLs.

The light microscopy photographs showed that the laser pits of explanted IOLs are mainly distributed in the outer part of the lens area, most of which were located at least 3mm away from the center of the optical zone. The MTF assessment of the two IOL groups demonstrated good and similar optical quality, exhibiting overall high contrast and a low potential to affect visual acuity. Both the C-Quant and the optical-bench straylight setup demonstrated elevated scattering from the laser pits, but the effect was localized and low. A subset of two samples with glistenings showed larger scattering effects of isolated glistenings than laser pits.

Our study demonstrates that laser pits have minimal impact on the imaging quality of IOLs, which may be related to the distribution of the laser pits, their limited number and size. However, those IOLs with glistenings greatly induced straylight, potentially leading to glare phenomena and a reduction in visual quality.