Comparative analysis of the visual performance after implantation of the toric implantable collamer lens in stable keratoconus: a 4-year follow-up after sequential procedure (CXL+TICL implantation)

Abstract

AimsTo report on 4-year postoperative visual performance with the toric implantable collamer lens (TICL) for stable keratoconus after sequential procedure (corneal collagen crosslinking plus TICL implantation).MethodsForty eyes of 24 patients with stable keratoconus with myopia between 0.00 and −18.00 dioptres (D) and astigmatism between 1.25 and 8.00 D were evaluated in this prospective interventional study (https://clinicaltrials.gov/ct2/show/NCT02833649). We evaluated refraction, visual outcomes, astigmatic changes analysed by Alpins vector, contrast sensitivity, aberrometry, modulation transfer functions (MTFs), defocus curve, and operative and postoperative complications.ResultsAt 4-year follow-up, 45% had 20/20 vision or better and 100% had 20/40 or better uncorrected visual acuity (UCVA). Vector analysis of refractive astigmatism shows that the surgically induced astigmatism (SIA) (3.20±1.46 D) was not significantly different from the target induced astigmatism (TIA) (3.14±1.42 D) (p=0.620). At 4 years postoperatively, none of the eyes showed a decrease in UCVA, in contrast to 24 eyes in which UCVA was increased by ≥1 lines, with contrast sensitivity and improvement in total aberrations and MTF value at 5 per degree (*p=0.004) after TICL implantation. The cumulative 4-year corneal endothelial cell loss was ≤5%. No patients reported dissatisfaction. At the end of follow-up, the vault was 658±54.33m (range, 500–711) and the intraocular pressure was 11.7±2.08 mm Hg. Occurrences of glare and night-driving troubles diminished after TICL surgery.ConclusionThe results from this standardised clinical investigation support TICL implantation from clinical and optical viewpoints in patients with stable keratoconus.Trial registration numberNCT02833649, Pre-results

Outcomes of two different treatment modalities in mild to moderate keratoconus

“…In this study, efficacy index was 1.08 and safety index was 1.19 and so, our results are comparable to the published studies on the outcomes of ICL implantation in keratoconus [ 15 – 19 ]…”

Outcomes of two different treatment modalities in mild to moderate keratoconus

“…On the other side this study regarding ICL implantation variability in the subjective refraction (on which the TICL power and axis of insertion is based on) in keratoconic eyes makes the accuracy in such patients is less and refractive surprises are more than in normal non-keratoconic eyes. [14] In this study, e cacy index was 1.08 and safety index was 1.19 and so, our results are comparable to the published studies on the outcomes of ICL implantation in keratoconus [15,16,17,18,19] Hashemian et al [20] showed better e cacy and safety indices of 1.345 and 1.56 respectively at 1 year postoperative. These differences could be explained by the different preoperative data reported by Hashemian et ) and as usual keratoconic eyes data are unexpected specially preoperative due to presence of another factors that is not totally related to the refraction which are the aberrations.…”

Keratoconus: exploring fundamentals and future perspectives – a comprehensive systematic review

“… 132 , 133 The main causes of this are keratoconus’s irregular astigmatism profile and the other, which is connected to the first, because it might be challenging to get refraction in keratoconus patients, particularly in those with severe ametropia. 134 …”

“…To attain the targeted optimum vault and ideal size, different modalities have been proposed, and some of them take advantages of AI, such as the manual mode of WTW computation from the Eyemetrics toolbox, the Orbscan IIz slit scanning approach, 135 summation methods with Pentacam HR, 136 ultrasound biomicroscopy (UBM) for STS measurement, 134 , 137 AS-OCT for ATA diameter, 138 crystalline lens rise (CLR), and lens vault. 137 Even though, ideal size has still the main significant repercussion during phakic IOL (intra-ocular lens) implantation.…”