Predicting Intraocular Lens Tilt Using OCT Measurements and Partial Least Squares Regression Modelling (Tilt)

Predicting Post-operative Intraocular Lens Tilt Using Optical Coherence Tomography Measurements and Partial Least Squares Regression Modelling

During cataract surgery an artificial intraocular lens (IOL) is implanted in the eye to replace the lens and to correct the refraction for distance vision. Misalignment of IOLs can cause severe loss of visual quality. Different types of misalignment are known. Tilt, one type of IOL misalignment is thought to play a negative role for the optical performance in eyes with IOL designs, especially, if they have aspheric, toric, or multifocal optics.

Various methods to measure IOL misalignments have been described. Studies assessing the IOL position have used subjective grading methods at the slit lamp examination or a Scheimpflug camera to assess IOL decentration and tilt. The subjective grading at the slitlamp may display considerable variability between examiners. This method is more qualitative than quantitative and does not allow fine resolution when reporting IOL tilt. The fact that the patient has no standardized target to focus on makes the method even less reliable. Scanning methods such as Scheimpflug photos require a very well dilated pupil exceeding 6mm to assess the IOL position. Additionally, it can be difficult to identify the anatomical structures of the eye that need to be used as points of reference. Scheimpflug camera images have been used for assessing IOL tilt previously, but erroneous results, often due to corneal magnification, have diminished their widespread use. Another possibility to assess tilt is the use of Purkinje reflexes. The light reflections of Purkinje images at ocular surfaces to evaluate ocular alignment have recently been utilized. Since light is reflected at all interfaces of media with a difference in refractive index, these reflections, called Purkinje images, can be used to assess tilt and decentration of IOLs. Two different clinically applicable Purkinjemeter system provide the measurement of IOL decentration and tilt. The main problem with Purkinje meters is accessibility, as there are only a few prototypes available worldwide.

The most recently developed method for tilt quantification is the use of optical coherence tomography. This method has several advantages compared to the previous methods: OCT based devices are available in most clinics, the resolution of modern OCT devices is high, and the measurements are reproducible.

Aim of this study is to measure tilt with two modern OCT based devices and one Scheimpflug camera and to predict the post-operative tilt using partial least squares regression. This method was developed by Wold and introduced to ophthalmology previously.

Study Overview

• Status: Completed
• Conditions: Cataract; Intraocular Lens
• Intervention / Treatment: Other: Optical Coherence Tomography

Detailed Description

During cataract surgery an artificial intraocular lens (IOL) is implanted in the eye to replace the lens and to correct the refraction for distance vision. Misalignment of IOLs can cause severe loss of visual quality. Different types of misalignment are known. Tilt, one type of IOL misalignment is thought to play a negative role for the optical performance in eyes with IOL designs, especially, if they have aspheric, toric, or multifocal optics. For example, in the case of aspheric IOLs, it appears that even slight amount of tilt may result not only in the loss of the effect of reducing spherical aberrations but in more severe cases even a worsening of the optical quality compared to spherical IOLs. In the case of toric IOLs, tilt introduces higher order aberrations potentially mimicking astigmatism. In the case of multifocal IOLs, tilt increases higher order aberrations, which leads to decreased visual quality.

Various methods to measure IOL misalignments have been described. Studies assessing the IOL position have used subjective grading methods at the slit lamp examination or a Scheimpflug camera to assess IOL decentration and tilt. The subjective grading at the slitlamp may display considerable variability between examiners. This method is more qualitative than quantitative and does not allow fine resolution when reporting IOL tilt. The fact that the patient has no standardized target to focus on makes the method even less reliable. Scanning methods such as Scheimpflug photos require a very well dilated pupil exceeding 6mm to assess the IOL position. Additionally, it can be difficult to identify the anatomical structures of the eye that need to be used as points of reference. Scheimpflug camera images have been used for assessing IOL tilt previously, but erroneous results, often due to corneal magnification, have diminished their widespread use. Another possibility to assess tilt is the use of Purkinje reflexes. The light reflections of Purkinje images at ocular surfaces to evaluate ocular alignment have recently been utilized. Since light is reflected at all interfaces of media with a difference in refractive index, these reflections, called Purkinje images, can be used to assess tilt and decentration of IOLs. Two different clinically applicable Purkinjemeter system provide the measurement of IOL decentration and tilt. The main problem with Purkinje meters is accessibility, as there are only a few prototypes available worldwide.

The most recently developed method for tilt quantification is the use of optical coherence tomography. This method has several advantages compared to the previous methods: OCT based devices are available in most clinics, the resolution of modern OCT devices is high, and the measurements are reproducible.

Due to the fact that tilt has an influence on visual quality, the prediction of the post-operative tilt could improve IOL power calculation significantly, especially for toric IOLs. In the literature, the prediction of tilt was shown to be acceptable for the orientation of tilt, but not for the amount of tilt. Furthermore, there is disagreement concerning the fact, if the amount of tilt increases or decreases after cataract surgery.

Aim of this study is to measure tilt with two modern OCT based devices and one Scheimpflug camera and to predict the post-operative tilt using partial least squares regression. This method was developed by Wold and introduced to ophthalmology previously.

• Study Type: Observational
• Enrollment (Actual): 110

Contacts and Locations

Study Locations

• Austria
  • Oberösterreich
    • Linz, Oberösterreich, Austria, 4020
      • Matthias Bolz

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

patients who undergo planned cataract surgeries above 21 years

Description

Inclusion Criteria:

• Planned cataract surgery in one or both eyes
• Above 21 years of age

Exclusion Criteria:

• Combined surgery (cataract plus glaucoma/vitreoretinal/corneal surgery)
• Best corrected distance visual acuity below 0.05 Snellen
• Pathologies that could have an influence on the post-operative tilt, such as pseudoexfoliation syndrome or previous ophthalmic trauma, or other reasons for phakodonesis.
• Previous ophthalmic surgery that could have an influence on post-operative tilt, such as pars plana vitrectomy
• In case of pregnancy (pregnancy test will be taken preoperatively in women of reproductive age)

Study Plan

How is the study designed?

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
post operative IOL tilt	Predicting the post-operative tilt using PLS regression	8 weeks post cataract surgery

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Comparison of tilt prediction	Bilateral comparison of tilt prediction	8 weeks post cataract surgery
comparion of three measurement methods	Comparison between the three measurement methods concerning amount of tilt, orientation of tilt and tilt prediction	8 weeks post cataract surgery
Comparison of tilt pre- versus post operative	Change of tilt from pre-operatively to post-operatively	pre operative at screening and 8 weeks post cataract operation

Collaborators and Investigators

• Sponsor: Johannes Kepler University of Linz
• Investigators: Principal Investigator: Nino Hirnschall, MD, JKU Linz

Study record dates

Study Major Dates

• Study Start (Actual): April 12, 2022
• Primary Completion (Actual): April 1, 2023
• Study Completion (Actual): April 26, 2023

Study Registration Dates

• First Submitted: March 9, 2023
• First Submitted That Met QC Criteria: March 5, 2024
• First Posted (Actual): March 12, 2024

Study Record Updates

• Last Update Posted (Actual): March 12, 2024
• Last Update Submitted That Met QC Criteria: March 5, 2024
• Last Verified: March 1, 2024

More Information

Terms related to this study

• Keywords: Tilt
• Additional Relevant MeSH Terms: Eye Diseases; Lens Diseases; Cataract
• Other Study ID Numbers: KUK-Ophthalmology-009

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No