Improving Visual Quality in Patients With Irregular Corneas Using Asymmetrical Toric Intraocular Lenses
Trial statusRecruiting
Trial phaseNot applicable
Trial typeInterventional
Biological sexAll
Age21+
SponsorJohannes Kepler University of Linz
About this trial
Cataract surgery in patients with irregular corneas presents unique challenges, primarily due to the high variability in keratometry and corneal tomography measurements, which complicates accurate intraocular lens (IOL) calculations. In these patients, therapeutic options are currently limited to either non-toric IOLs and rigid contact lenses postoperatively or conventional toric IOLs for the reduction of total astigmatism within cataract surgery. While conventional toric IOLs may be beneficial in selected cases with a stable astigmatic pattern and clear axis, their effectiveness is largely limited, as significant irregularity and higher order aberrations reduce predictability, accuracy of formulae, and refractive outcomes. Therefore, the development of a reliable method to reduce total astigmatism - including irregular components - would represent a major advancement, potentially improving both visual function and patient quality of life. The aim of this exploratory study is to evaluate the effectiveness of customized toric intraocular lenses (AMILens Individual, AMIPLANT GmbH, Germany) in reducing total corneal astigmatism in patients with a significant irregular astigmatic component. These lenses are designed to address corneal aberrations up to the 6th Zernike order, thereby extending correction beyond the capabilities of conventional toric IOLs. To our knowledge, no clinical study has yet investigated this novel approach.
Eligibility criteria
This trial does not accept healthy volunteersQualifiers
Age 21 years or older
Scheduled cataract surgery
At least 1.75 D of total astigmatism in the CASIA2 measurement
At least 0.75 D of asymmetry or higher order irregularity within the 6mm zone of the real (total) index corneal refractive map of the CASIA2 measurements
Disqualifiers
Relevant central corneal scars
PEX, previous ocular surgery, severe trauma or any pathology that could lead to an unstable capsular bag
Combined surgery (cataract plus glaucoma/vitreoretinal/corneal surgery)
Postoperative best corrected distance visual acuity below 0.3 Snellen decimal
Trial design
Design model
Single group
Treatments tested in this trial
AMILens Individual
DeviceAn acrylic hydrophilic, one piece 4-loop haptic, monofocal, toric IOL (AMILens Individual, AMIPLANT GmbH, Germany) will be implanted into the capsular bag after removal of the of the natural lens. This IOL is CE-certified. Asphericity and dioptric power of the IOL are customized for each individual eye.
Treatment groups
15 Participants
are divided into 1 treatment groupGroup A: AMILens Individual ImplantationActive comparator 1 intervention
Trial outcomes
Primary outcomes
1
Change of Astigmatism
The change of astigmatism is defined by the difference of the postoperative total refractive/ocular astigmatism (assessed via subjective refraction) to the preoperative corneal astigmatism (assessed via the utilized measurement devices). Reduction in total ocular (refractive) astigmatism will be quantified as both absolute reduction (Diopter) and relative reduction (%). Descriptive statistics will include mean, standard deviation, median, interquartile range, and range. Normality will be tested using the Shapiro-Wilk test and Q-Q plots. If normally distributed: comparisons between preoperative and postoperative values will be assessed with a paired t-test. If not normally distributed: the Wilcoxon signed-rank test will be applied. Results will be presented with 95% confidence intervals. As this is an exploratory study, p-values will be reported descriptively, and values below 0.05 will not be interpreted as statistically significant.
Time frame
4-8 weeks post-surgerySecondary outcomes
1
Agreement of measured variables for astigmatism across devices
The agreement of the variables anterior corneal astigmatism, posterior corneal astigmatism, total corneal astigmatism, Zernike Polynomials first to seventh order, lower order aberrations (LOAs), and higher order aberrations (HOAs) are compared across the utilized measurement devices Pentacam, Anterion, ms39, and CASIA2. All mentioned variables are on a ratio scale. Agreement between different devices will be assessed using: Bland-Altman analysis (mean difference and 95% limits of agreement),Intraclass correlation coefficients (ICCs) for reliability, and, where appropriate, repeated-measures ANOVA or Friedman test (non-parametric) across multiple modalities.
Time frame
4-8 weeks post cataract surgery2
Change of higher order optical aberrations (HOAs)
Higher order optical abberation values are measured posoperatively for the whole eye (cornea and lens) with the osiris device, and compared to the preoperative corneal higher order abberations, which are measured with the Casia2 and the ms39 devices. Reduction in higher order aberrations will be quantified as both absolute reduction (D) and relative reduction (%). The same descriptive statistics, normality testing, and comparison testing as described above will be applied. Results will be presented with 95% confidence intervals and p-values will be reported descriptively.
Time frame
4-8 weeks post cataract surgery3
Surgically induced corneal astigmatism (SIA)
Surgically induced corneal astigmatism (SIA) will be evaluated by calculating the vectorial changes of corneal astigmatism (magnitude ind diopter and axis in degree) between preoperative and postoperative corneal astigmatism measurements for each measurement device
Time frame
From enrollment to the end last study visit (4-8 weeks post surgery)4
Postoperative uncorrected and best-corrected distance visual acuity
These values are assessed via standardized subjective refraction using the jackson cross cylinder method, and will be described descriptively in logMAR unit. Postoperative uncorrected and best-corrected visual acuity will be analyzed as both continuous variables and using threshold-based categories. Descriptive statistics will include mean, standard deviation, median, interquartile range, and range.
Time frame
4-8 weeks post cataract surgerySponsors and contacts
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Source ClinicalTrials.gov