Surgically induced astigmatism in the scleral fixated 'Carlevale' IOL technique

Purpose: To evaluate the surgically induced astigmatism over a 6-month follow-up period in patients who underwent scleral IOL fixation using an acrylic single-piece IOL with special haptics designed for sutureless scleral fixation. Methods: We conducted a prospective longitudinal study at a single site with a single surgeon. We included patients who received transscleral IOL implantation following the Carlevale technique and were followed up post-operatively for 24 weeks. We measured the patient's refraction at baseline, week 12 and week 24 using the best corrected visual acuity at 4 m (EDTRS chart). We performed corneal tomography at every visit using an anterior segment optical coherence tomography (AS-OCT). We evaluated surgically induced astigmatism (SIA) and refraction during each follow-up visit and compared them to baseline. We then assessed changes in SIA over time. Results: In total, 27 eyes of 27 patients consisting of 16 female and 11 male individuals were evaluated. The mean patient age was 71 +/- 11.7 years, mean axial length was 24.30 +/- 1.47 mm (range: 21.4-27.23) and mean white-to-white distance was 12.07 +/- 0.40 mm (range: 11.4-12.7). The mean SIA decreased from 1.78 +/- 0.96D at week 1 significantly to 0.80 +/- 0.55D at week 12 (p < 0.001) and then stayed unchanged around 0.82 +/- 0.72D at week 24 (p = 1.0). Conclusions: The scleral fixated Carlevale IOL and its implantation procedure were found to result in a predictable SIA of <1D after 24 weeks. However, the axis orientation of the SIA appeared to be random, making it unsuitable for implementation in toric IOL calculations.