Quantitative In Vivo Assessment Of Intraocular Lens Calcification: Correlation Between Optical Coherence Tomography Opacity And Straylight Measurement

To quantitatively assess intraocular lens (IOL) calcification in vivo using anterior segment optical coherence tomography (AS-OCT) and correlate these findings with straylight measurements. The goal is to evaluate AS-OCT's potential as a diagnostic tool to aid surgical decision-making in patients with visual impairment due to IOL opacification.

Department of Ophthalmology, Heidelberg University Hospital, Heidelberg, Germany.

This prospective observational clinical study included 35 eyes from 35 patients (mean age 72.9 ± 7.8 years) with homogenous IOL calcification. Calcified IOLs were imaged using AS-OCT, and their opacity was quantified automatically with a custom MATLAB script. Straylight was measured with the C-Quant straylight meter. Correlation between AS-OCT opacity and straylight was assessed using Spearman’s rho coefficient. Additionally, a linear regression model was established to predict straylight values based on OCT opacity measurements to assess its utility as a surgical decision tool.

The mean IOL opacity was 69.15 ± 13.55 Pixel Intensity Unit (PIU), and mean straylight was 2.24 ± 0.38 log(s). A statistically significant correlation was observed between lens opacity and straylight values (rho = 0.494, p = 0.003). Patients opting for IOL exchange had a higher IOL opacity (75.69 ± 7.58 PIU) and straylight value (2.33 ± 0.30 log(s)). Linear regression established a model linking opacity to straylight: straylight = 29.77 + 17.57 × IOL opacity [log(s)] with R² = 0.244.

AS-OCT effectively quantifies IOL calcification and correlates significantly with functional impairment. It provides a fast, non-invasive, objective and robust diagnostic tool, potentially aiding decision-making in borderline surgical cases. A cutoff value of 57.18 PIU for IOL opacity could serve as a guiding criterion for determining the need for IOL exchange surgery.