Postoperative Total Wavefront Pattern Between Two Types of Intraocular Lenses Implanted in Cataract Surgery

Difference in Postoperative Total Wavefront Pattern Between Aspheric and Negative Spherical Aberration Intraocular Lenses Implanted in Cataract Surgery

With the advancement of cataract eye surgery and wavefront sensors, the previously unquantifiable refractive measurements have been identified and the high order aberrations have shown their effect on high resolution imaging.

In the human phakic eye, the shape of the normal cornea induces average positive spherical aberration and remains unchanged over time, whereas the crystalline lens has a negative spherical aberration. As a result, overall spherical aberration in the young eye is low.

However, the compensation slowly decreases with the aging lens and is fully lost after cataract extraction and implantation of a standard intraocular lens.

Optical studies showed that conventional biconvex spherical intraocular lenses add their intrinsic positive spherical aberration to the positive spherical aberration of the cornea resulting in image imperfection and blur. As a useful side effect, this also increases the depth of focus -often referred to as pseudo-accommodation.

New Aspheric intraocular lenses designs currently in use impart negative spherical aberration, about 0.17 to 0.20 microns of negative spherical aberration. This added negative spherical aberration partially corrects the average amount of corneal positive spherical aberration & compensate for its effect. Our study will include (FocusForce foldable aspheric intraocular lens, Bausch & Lomb, New Jersey, USA) as an example of this type of negative spherical aberration intraocular lenses.

In order to improve retinal image quality without compromising depth of field, or introducing other aberrations, aberration-free aspheric intraocular lenses were developed with no inherent spherical aberration.

The other intraocular lens targeted in our study (Akreos AO Microincision lens, Bausch & Lomb, New Jersey, USA) is an example of this type of IOLs.

Study Overview

• Status: Unknown
• Conditions: Cataract
• Intervention / Treatment: Procedure: phacoemulsification with intraocular lens implantation; Device: ocular aberrometer assesment

Detailed Description

A customized correction for the individual eye seems to be the most promising solution for tailored correction of spherical aberration.

On the other hand, Wave front analysis of the ocular optical system has increased our knowledge of the aberrations in the eye. The importance of measuring optical aberrations lies not only in the presence of natural aberrations in the human eye, but also in its usefulness for evaluating individual surgical outcomes. By using Zernike polynomials, the aberrations of the ocular system can be characterized. Zernike coefficients of the higher-order aberrations can be derived from corneal topographic data. And for those generated by the whole optical system of the eye can be derived from aberrometry.

With current small-incision cataract surgery, it has been reported that the average postoperative corneal topography does not differ significantly from average preoperative corneal topography, so in our study we will focus on the ocular & internal wave front changes.

With the high resolution pyramid wavefront sensor incorporated in (SCHWIND PERAMIS®, topography and Aberrometry, Kleinostheim, Germany) we will evaluate and compare the total ocular wave front and the corneal wave front in our study to identify and estimate the internal aberrations . This new sensor uses an extended source instead of a point-like source avoiding in this manner the oscillation of the pyramid.

SCHWIND PERAMIS evaluates the ocular wave front aberrations with 45,000 measuring points - without any overlap and with clear assignment of each point & records 33 images per second and automatically selects the image with the best measurement. Together with real-time measurement, this ensures a new level of detail resolution and precision. SCHWIND PERAMIS can also be used to compare a patient's corneal and ocular wave front data. The direct comparison provides information about whether a visual defect is located on the surface of the cornea or within the eye itself, thus allowing us to identify and evaluate internal aberrations.

• Study Type: Interventional
• Enrollment (Anticipated): 40
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Egypt
  • Cairo, Egypt, 12563
    • Recruiting
    • facultyof medicine, Cairo university

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 21 years to 75 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

1-All patients with written informed consent, between the age of 21 -75 years who will undergo phacoemulsification procedure with intraocular lens implantation of one of the targeted lenses in the study

Exclusion Criteria:

1. Previous corneal intervention or refractive surgery.
2. Persistent Corneal edema (epithelial or stromal).
3. Co-existing corneal pathology.
4. Ocular surface disease & Dry eye syndrome.
5. Posterior capsular opacity .
6. Anterior capsular contraction (phimosis).
7. Ocular inflammation.
8. Co-existing Vitreoretinal diseases.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: aberration-free IOL; 20 human eyes with aberration-free intraocular lens Implantation after phacoemulsification cataract surgery	Procedure: phacoemulsification with intraocular lens implantation; treatment of cataract by phacoemulsification procedure and implantation of different types of IOLs.; Device: ocular aberrometer assesment; evaluate total ocular wavefront, corneal wavefront & internal wavefront (High order aberrations ) post operative by corneal tomography and aberrometer
Active Comparator: negative spherical aberration IOL; 20 human eyes with negative spherical aberration intraocular lens Implantation after phacoemulsification cataract surgery	Procedure: phacoemulsification with intraocular lens implantation; treatment of cataract by phacoemulsification procedure and implantation of different types of IOLs.; Device: ocular aberrometer assesment; evaluate total ocular wavefront, corneal wavefront & internal wavefront (High order aberrations ) post operative by corneal tomography and aberrometer

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Corneal, Ocular, and Internal spherical aberrations	assessment of ocular, corneal & internal wavefront by aberrometer & corneal tomography	1 month postoperative

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
corneal wavefront changes	• Compare pre-operative and post-operative corneal spherical aberrations of every patient and evaluate any significant changes.	1 month postoperative
near vision addition	the plus lenses needed to be add to correct near vision which reflect the depth of focus of the IOL implanted	1 month postoperative

Collaborators and Investigators

• Sponsor: Cairo University
• Investigators: Principal Investigator: Aya G Ibrahim, MBBCh, Dar El Oyoun ophthalmology hospital

Study record dates

Study Major Dates

• Study Start (Actual): November 9, 2020
• Primary Completion (Anticipated): June 30, 2021
• Study Completion (Anticipated): June 30, 2021

Study Registration Dates

• First Submitted: January 6, 2021
• First Submitted That Met QC Criteria: January 6, 2021
• First Posted (Actual): January 8, 2021

Study Record Updates

• Last Update Posted (Actual): January 13, 2021
• Last Update Submitted That Met QC Criteria: January 11, 2021
• Last Verified: January 1, 2021

More Information

Terms related to this study

• Keywords: phacoemulsification; intraocular lens; wavefront; aberration-free; negative spherical aberration
• Additional Relevant MeSH Terms: Eye Diseases; Lens Diseases; Cataract
• Other Study ID Numbers: 336-2020

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: Yes
• product manufactured in and exported from the U.S.: Yes