Assessing the Astigmatism Reducing Effect With Toric IOLs in Eyeswith Low Astigmatism

Not Applicable

• Conditions: Cataract; Astigmatism
• Interventions: Procedure: toric intraocular lens; Procedure: non toric intraocular lens

• Registration Number: NCT03538964
• Lead Sponsor: Prim. Prof. Dr. Oliver Findl, MBA

Brief Summary

Comparison of the astigmatism reducing effect of a toric IOL with a non toric IOL in eyes with low corneal astigmatism.

Detailed Description

With increasing demands of patients concerning refractive outcome after cataract surgery, toric intraocular lenses (IOLs) that correct corneal astigmatism have been introduced more widely to cataract surgery. Originally, toric IOLs were used mainly for patients with high degrees of astigmatism. Since a couple of years, toric IOLs are available from numerous manufacturers to correct moderate amounts of astigmatism which are much more prevalent with about 8% having a corneal astigmatism of 2.0D or more in the cataract population. 5Using toric IOLs for these eyes results in less spectacle dependence of patients due to the astigmatic correction. Other astigmatism reducing techniques, such as peripheral corneal relaxing incisions and opposite clear corneal incisions were shown to be less predictable. Although the use of toric IOLs became the gold standard to correct corneal astigmatism during cataract surgery , there is still uncertainty, if low astigmatism should be corrected. Visser et al. showed that moderate astigmatism of than 1.5D should be corrected for monofocal IOLs and Hayashi showed that remaining astigmatism of 1.0D already decreases visual quality in eyes with multifocal IOLs. Although correction of low corneal astigmatism appears to be beneficial, some hurdles have to be taken into account. In eyes with low corneal astigmatism the accuracy of measuring the astigmatism meridian is relatively low. Furthermore, different corneal measurement techniques are not always comparable and it is difficult to know, which device shows the correct amount of astigmatism. Additionally, the correction of the spherical equivalent is of high importance, as a refractive surprise will also attenuate the astigmatism reducing effect of the toric IOL. Aim of this study is to assess, if toric IOLs are useful in patients with low amounts of corneal astigmatism and to quantify the sources of error in toric IOL power calculation.

Study Timeline

• Study First Submitted: 2018-04-30
• Study Start: 2018-05-02
• Study First Submitted QC: 2018-05-15
• Study First Posted: 2018-05-29
• Status Verified: 2019-10
• Last Update Submitted: 2019-10-01
• Last Update Posted: 2019-10-02
• Primary Completion: 2020-05-02
• Study Completion: 2020-08-01

Recruitment & Eligibility

• Status: UNKNOWN
• Sex: All
• Target Recruitment: 25

Inclusion Criteria

• cataract
• Age 21 and older
• Regular corneal astigmatism 0.5D up to 1.5 D and difference between eyes not more than 0.75D
• written informed consent prior to surgery

Exclusion Criteria

• relevant other ophthalmic diseases such as: pseudoexfoliation, glaucoma, traumatic cataract corneal scars, and other co-morbidity that could affect capsule bag stability ( e.g. Marfan syndrome)
• Irregular corneal astigmatism on corneal topography
• In case of pregnancy (pregnancy test will be taken preoperatively in women of reproductive age)

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Toric intraocular lens (IOL)	toric intraocular lens	toric intraocular lens for low astigmatism correction
Non toric intraocular lens (IOL)	non toric intraocular lens	non toric intraocular lens

Primary Outcome Measures

Name	Time	Method
Subjective refraction to detect remaining astigmatism (in Diopters) between both groups	12 months

Secondary Outcome Measures

Name	Time	Method
Wavefront analysis of high order aberrations (root mean square, in microns)	12 months
Purkinjemeter measurement of Tilt (in degrees) and Decentration (in degrees) of the intraocular lens	12 months
Biometrical measurement of axial length (in mm), anterior chamber depth (in mm), corneal astigmatism (radii and axial degrees)	12 months
Questionnaire to asses patients subjective satisfaction with visual outcome	12 months	In the questionnaire the patient has to choose if different tasks (e.g. reading, driving, watching TV) are easier for him/ her with the right eye, the left eye, or if there is no difference between both eyes

Trial Locations

Locations (1)

Vienna Institute for Research in Ocular Surgery (VIROS); 🇦🇹 Vienna, Austria