Plain English Summary
Background and study aims
Intraocular lenses (IOLs) are implanted inside the eye to replace the eye's natural lens when it is removed during cataract surgery. Trifocal diffractive IOLs have been demonstrated to restore intermediate vision without damaging distance or near vision. This new concept of IOL has confirmed good performance for visual outcomes, patient satisfaction and spectacle independence. However, patients’ corneal astigmatism (imperfection in the curvature of the cornea) is critical to the choice of trifocal diffractive IOL, which is a key factor influencing the visual acuity and refractive outcomes after the operation. Many studies have shown that the location of the corneal incision (cut) has an impact on postoperative corneal astigmatism and higher-order aberrations (HOAs), such as degradation of vision at night, halos and glare. However, there is no research on the effect of incisions on visual outcomes after implantation of trifocal diffractive IOLs. This study aims to evaluate visual acuity, corneal astigmatism and corneal HOAs after implantation of a trifocal diffractive IOL operated with either a corneal steep-axis incision or a 135° incision.
Who can participate?
Patients with cataract or presbyopia suitable for refractive lens exchange, who have pre-existing corneal astigmatism of less than 1.00 D, and who are seeking spectacle independence
What does the study involve?
Participants are randomly allocated to one of two groups: group A are treated with a 2.8 mm clear corneal incision at the steep-axis and group B are treated with a 2.8 mm clear corneal incision at 135°. According to their preoperative corneal astigmatism, groups A and B are separated into two subgroups: A1 (0 ~ 0.50 D), A2 (0.51 ~ 1.00 D), B1 (0 ~ 0.50 D), and B2 (0.51 ~ 1.00 D). Visual acuity, corneal astigmatism and corneal HOAs are followed up for 3 months. Visual outcomes are assessed between group A1 and group B1 and between group A2 and group B2 to evaluate the usability of the intervention.
What are the possible benefits and risks of participating?
After the end of the study the participants are expected to gain high-quality refractive outcomes and spectacle independence. There are no risks associated with the intervention.
Where is the study run from?
The Affiliated Hospital of Qingdao University (China)
When is the study starting and how long is it expected to run for?
December 2015 to March 2018
Who is funding the study?
1. National Natural Science Foundation of China
2. National Natural Science Foundation of Shandong
Who is the main contact?
Dr Shasha Xue
xueshasha1104@126.com
Trial website
Contact information
Type
Public
Primary contact
Dr Shasha Xue
ORCID ID
Contact details
The Affiliated Hospital of Qingdao University
No.16 Jiangsu Road
Shinan District
Qingdao
266000
China
+86 (0)17863961151
xueshasha1104@126.com
Additional identifiers
EudraCT number
ClinicalTrials.gov number
Protocol/serial number
N/A
Study information
Scientific title
Effect of incision on visual outcomes after implantation of a trifocal diffractive intraocular lens
Acronym
Study hypothesis
Visual outcomes with corneal steep-axis incision are better than 135° incision after implantation of trifocal diffractive intraocular lens (IOL).
Ethics approval
Ethics committee of the Affiliated Hospital of Qingdao University, 30/12/2015, ref: qddxfsyy2614
Study design
interventional randomised controlled study
Primary study design
Interventional
Secondary study design
Randomised controlled trial
Trial setting
Hospitals
Trial type
Treatment
Patient information sheet
Not available in web format, please use the contact details to request a patient information sheet
Condition
Patients undergoing cataract surgery with implantation of a trifocal diffractive IOL
Intervention
This prospective study enrolled patients randomly assigned to different groups. According to preoperative corneal astigmatism, patients were assigned into group A1 (0 ~ 0.50 D) or A2 (0.51 ~ 1.00 D) with a corneal steep-axis incision or group B1 (0 ~ 0.50 D) or B2 (0.51 ~ 1.00 D) with a 135° incision. Visual acuity, corneal astigmatism and corneal higher-order aberrations (HOAs) were followed up for 3 months.
Intervention type
Procedure/Surgery
Phase
Drug names
Primary outcome measure
1. Corneal astigmatism measured with a Galilei device (Galilei G2, Ziemer ophthalmic systems AG, Port, Switzerland) at 1 day, 2 weeks, 1 month, or 3 months postoperatively
2. Uncorrected distance visual acuity (UDVA), uncorrected intermediate visual acuity (UIVA) and uncorrected near visual acuity (UNVA) obtained by the standard logarithmic chart at 1 day, 2 weeks, 1 month, or 3 months postoperatively
3. Total corneal wavefront aberration, root mean square value of corneal higher-order aberrations (RMS HOAs), spherical aberration (SA), coma, or trefoil measured with a Galilei device (Galilei G2, Ziemer ophthalmic systems AG, Port, Switzerland) at 1 day, 2 weeks, 1 month, or 3 months postoperatively
Secondary outcome measures
1. The proportion of astigmatic axial length with the rule (WTR) (90°± 30°), against the rule (ATR) (0°to 30°or 150°to 180°), and oblique (30°to 60°or 120°to 150°) at pre operation and 3 months post operation
2. Surgically induced astigmatism (SIA) calculated using Jaffe/Clayman vector analysis at 3 months post operation
3. UDVA and CDVA between the subgroups obtained by the standard logarithmic chart pre operation
Overall trial start date
01/12/2015
Overall trial end date
31/03/2018
Reason abandoned (if study stopped)
Eligibility
Participant inclusion criteria
Patients with cataract or presbyopia suitable for refractive lens exchange seeking spectacle independence who had preexisting corneal astigmatism of less than 1.00 D
Participant type
Patient
Age group
Senior
Gender
Both
Target number of participants
101 eyes of 77 patients undergoing cataract surgery with implantation of a trifocal diffractive IOL (AT LISA tri 839MP, Carl Zeiss Meditec, Germany) were divided into two groups: group A including 49 eyes of 37 patients with a 2.8 mm clear corneal incision at the steep-axis and group B including 52 eyes of 40 patients with a 2.8mm clear corneal incision at 135°. According to the preoperative corneal astigmatism, groups A and B were separated into two subgroups: A1 (0 ~ 0.50 D with 22 eyes), A2 (0.51 ~ 1.00 D with 27 eyes), B1 (0 ~ 0.50 D with 23 eyes), and B2 (0.51 ~ 1.00 D with 29 eyes).
Participant exclusion criteria
Patients with a history of glaucoma, retinal detachment, corneal disease, irregular corneal astigmatism, abnormal iris, macular degeneration or retinopathy, neuro-ophthalmic disease, ocular inflammation, or previous ocular surgery
Recruitment start date
01/01/2016
Recruitment end date
31/12/2017
Locations
Countries of recruitment
China
Trial participating centre
The Affiliated Hospital of Qingdao University
No.16 Jiangsu Road
Shinan District
Qingdao
266000
China
Funders
Funder type
Government
Funder name
National Natural Science Foundation of China (81470609, 81300730)
Alternative name(s)
National Science Foundation of China, Natural Science Foundation of China, NSFC
Funding Body Type
government organisation
Funding Body Subtype
Federal/National Government
Location
China
Funder name
National Natural Science Foundation of Shandong (ZR2017BH025)
Alternative name(s)
Funding Body Type
Funding Body Subtype
Location
Results and Publications
Publication and dissemination plan
Planned publication in a high impact peer-reviewed journal.
IPD sharing statement
Data will be available indefinitely at the Data Repository of the Affiliated Hospital of Qingdao University. All of the individual participant data collected during the trial will be shared after deidentification. Participant Information sheet, Study Protocol, Statistical Analysis Plan, Informed Consent Form, and Clinical Study Report will also be available. Data will be available immediately following publication with no end date for anyone who wishes to access the data for any purpose. Anyone who intends to access the datasets could contact Dr Shasha Xue (xueshasha1104@126.com).
Intention to publish date
15/07/2018
Participant level data
Stored in repository
Basic results (scientific)
Publication list
2018 results in: https://www.ncbi.nlm.nih.gov/pubmed/30005634