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NCT Number: NCT07452042

Postoperative Outcomes of a Toric AddOn 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.

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Key information

Conditions

Cataract and IOL Surgery Cataract Eye Diseases Keratoplasty Lens Diseases Toric Intraocular Lens Stability

Age range

45 year–95 year

Sex eligibility

All sexes

Study type

Observational

Primary location

Medical University of Vienna, Department of Ophthalmology and Optometry

Vienna, State of Vienna, 1090, Austria

Location status: Recruiting

Location contact

Nikolaus Mahnert, M.D.

CONTACT

[email protected]

0043 140400 79450

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Gender: female, male, or diverse
  • Ophthalmological diagnosis: pseudophakic patients after keratoplasty
  • Age: 45 to 90 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

Treatment and study plan

AddOn toric IOL implantation

Procedure

Implantation of a toric AddOn IOL in the ciliary sulcus of patients after cataract surgery and keratoplasty with a high postoperative refractive cylinder.

Primary outcomes

  1. 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.

Secondary outcomes

  1. 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.

  2. 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.

  3. 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. 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.

Sponsors and collaborators

Lead sponsor

Medical University of Vienna

Other

Registry information

Official study title

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

Acronym: AddOn

Important dates

Study start
2026
Primary completion
2029
Study completion
2029
First posted
Mar 5, 2026
Registry last updated
Mar 5, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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