Postoperative Outcomes of a Toric AddOn Intraocular Lens After Keratoplasty and Cataract Surgery (AddOn)

September 1, 2026 updated by: Daniel Schartmüller, Medical University of Vienna

Postoperative Outcomes of a Toric Add-On Intraocular Lens After Keratoplasty and Cataract Surgery

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.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Study Type

Observational

Enrollment (Estimated)

40

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Austria
    • State of Vienna
      • Vienna, State of Vienna, Austria, 1090
        • Recruiting
        • Medical University of Vienna, Department of Ophthalmology and Optometry
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

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.

Description

Inclusion Criteria:

  • Gender: female, male, or diverse
  • Ophthalmological diagnosis: pseudophakic patients after keratoplasty
  • Age: 45 to 95 years
  • Complication-free cataract surgery using phacoemulsification and implantation of a posterior chamber lens.
  • Complication-free keratoplasty and regular postoperative corneal astigmatism > 1 diopter (D)
  • Pupil diameter in mydriasis > 5.5 mm

Exclusion Criteria:

  • Uncontrolled glaucoma
  • Proliferative diabetic retinopathy
  • Iris neovascularization
  • History of uveitis or iritis
  • Microphthalmus
  • Recurrent intraocular inflammation of unknown cause
  • Blindness in the other eye
  • Uncontrolled systemic or ocular disease
  • Pregnancy
  • Breastfeeding

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Mean Postoperative Refractive Cylinder (Diopters)
Time Frame: 4-7 months

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.
4-7 months

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Mean Absolute IOL Rotation from Intended Axis (Degrees)
Time Frame: 4-7 months
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.
4-7 months
Mean IOL Decentration (Millimeters)
Time Frame: 4-7 months

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.
4-7 months
Mean IOL Tilt (Degrees)
Time Frame: 4-7 months
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.
4-7 months
Mean Axial Position Change of IOL (Millimeters)
Time Frame: 4-7 months
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.
4-7 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Medical University of Vienna

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

August 27, 2026

Primary Completion (Estimated)

February 1, 2029

Study Completion (Estimated)

February 1, 2029

Study Registration Dates

First Submitted

February 23, 2026

First Submitted That Met QC Criteria

February 27, 2026

First Posted (Actual)

March 5, 2026

Study Record Updates

Last Update Posted (Actual)

September 4, 2026

Last Update Submitted That Met QC Criteria

September 1, 2026

Last Verified

February 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 1710/2025

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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