An observational study in Cataract and IOL Surgery, Keratoplasty and Toric Intraocular Lens Stability, sponsored by Medical University of Vienna. Recruiting at 1 site in Austria. Open to participants aged 45 Years to 95 Years. Per ClinicalTrials.gov, last updated 2026-09-04.
Sponsored by Medical University of Vienna · Observational
The aim of this clinical study is to evaluate a toric add-on intraocular lens (IOL) for the correction of high astigmatism in patients who have undergone keratoplasty and cataract surgery. As this patient group often suffers from significant preoperative residual astigmatism, there is a relevant clinical need for effective and safe refractive treatment options. The implantation of a toric add-on IOL in the ciliary sulcus is intended to significantly reduce postoperative astigmatism and improve visual rehabilitation.
The study is designed as a prospective, monocentric clinical trial with a limited number of cases, as this is a rare condition with limited availability of suitable patients. It is being conducted in accordance with Section 3 of the Austrian Medical Devices Act (MPG 2021) and is investigating a CE-marked add-on intraocular lens implant used within its intended purpose. The postoperative refractive cylinder serves as the primary endpoint, as it reflects the actual effectiveness of astigmatism correction. The rotational stability of the add-on IOL, which significantly influences refractive precision, is recorded as a secondary endpoint.
All study participants will be examined pre- and postoperatively in accordance with applicable medical standards. The results should contribute to the optimization of refractive care after keratoplasty and assess the clinical applicability of toric AddOn IOLs in this specific indication.
1,629 studies on the registry are indexed under Cataract; 235 are open to participants now.
This study's planned enrollment of 40 is below the median of 89 across 475 observational studies indexed under Cataract.
Browse Cataract studies →Medical University of Vienna is the lead sponsor of 1,109 studies on the registry; 184 are open to participants now.
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Patients scheduled for add-on toric intraocular lens (IOL) implantation due to high postoperative refractive cylinder after keratoplasty and cataract surgery at the University Department of Ophthalmology and Optometry are screened during the preoperative examination. Interested patients are informed about the study's objectives and procedures and, upon consent, are enrolled.
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Exclusion Criteria:
Implantation of a toric AddOn IOL in the ciliary sulcus of patients after cataract surgery and keratoplasty with a high postoperative refractive cylinder.
Mean Postoperative Refractive Cylinder (Diopters)
The primary endpoint is the proportion of eyes achieving a ≥50% reduction in refractive cylinder postoperatively at the last visit (4 - 7 months). The postoperative refractive cylinder will be assessed by subjective refraction using a Snellen chart at 6 m. A one-sided exact binomial test (α = 0.05) will be used to determine if this proportion is greater than 70%. The 90% two-sided Clopper-Pearson confidence interval will also be reported.
Time frame: 4-7 months
Mean Absolute IOL Rotation from Intended Axis (Degrees)
The rotation of the IOLs over the first 4-7 postoperative months will be assessed with retroillumination photography (intraoperatively, 1 hour postoperatively, 1 week postoperatively, 1 month postoperatively, 6 months postoperatively). These images will be imported into the semi-automated evaluation software Rotix (labVIEW, National Instruments, Austin, Texas, USA). Two lines will be drawn to determine the IOL axis: one between two non-movable vessels serving as the reference axis, and a second one between the axis markings of the IOL. The Rotix software will then automatically calculate the axis difference between follow-up visits.
Time frame: 4-7 months
Mean IOL Decentration (Millimeters)
Assessment of IOL decentration will be performed under mydriatic conditions using the AS-OCT Casia 2 (Tomey Corporation, Nagoya, Japan) preoperatively, as well as at 1 week, 1 month and 6 months postoperatively. Decentration will be calculated using the cataract module with semi-automatic correction. IOL decentration will be defined as the horizontal and vertical distance from the center of the lens to the corneal vertex.
Time frame: 4-7 months
Mean IOL Tilt (Degrees)
Assessment of tiltwill be performed under mydriatic conditions using the AS-OCT Casia 2 (Tomey Corporation, Nagoya, Japan) preoperatively, as well as at 1 week, 1 month and 6 months postoperatively. Tilt will be calculated using the cataract module with semi-automatic correction. IOL tilt will be defined as the horizontal and vertical angle of the lens relative to the corneal vertex.
Time frame: 4-7 months
Mean Axial Position Change of IOL (Millimeters)
The aqueous depth (AQD) will be measured preoperatively and at 1 week and 6 months postoperatively using the AS-OCT Casia 2, all under maximum pupil dilation. Postoperative axial stability of the toric AddOn IOL will be calculated by subtracting the 1-week AQD from the 6-month AQD. Accordingly, a positive value will indicate a hyperopic shift and a negative value will indicate a myopic shift.
Time frame: 4-7 months
Started Aug 2026 (actual). Primary completion is estimated for Feb 2029, 30 months after the start.
Of 167 non-industry observational studies under Cataract, half reached primary completion within 19 months of starting (the median), counting those still running; a quarter within 9 and three quarters within 30. This study's planned 30 months is above that.
Counting every sponsor, half of 234 studies reached it within 16 months; a quarter within 9 and three quarters within 30.
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