Refractive Outcomes and Ocular Biometry of Two Swept-Source Optical Coherence Tomography-Based Biometers With Segmental or Equivalent Refractive Indices (ORION) (ORION)

Refractive Outcomes and Ocular Biometry of Two Swept-Source Optical Coherence Tomography-Based Biometers With Segmental or Equivalent Refractive Indices (ORION): A Non-Inferiority Randomized Clinical Trials

This prospective, single-centre, randomized, parallel-group comparative clinical study evaluated the refractive prediction accuracy of two swept-source optical coherence tomography (SS-OCT) biometers in a Thai cataract surgery cohort. The ARGOS biometer applies segmental refractive indices to individual ocular segments, whereas the IOLMaster 700 applies an equivalent refractive index to the whole eye. Each device is conventionally paired with a different keratometry-formula combination: ARGOS with the standard Barrett Universal II (Barrett UII K), and IOLMaster 700 with the Barrett Universal II using total keratometry (Barrett UII TK). The study compared these two device-formula pairings as they are used in routine clinical practice. Both biometers were performed on every eye on the same day, enabling a within-subject paired comparison of biometric agreement and refractive prediction error at one month after phacoemulsification cataract surgery with implantation of a TECNIS Monofocal one-piece IOL (model GCB00V)

Study Overview

• Status: Completed
• Conditions: Cataract
• Intervention / Treatment: Device: IOLMaster 700 (Carl Zeiss Meditec AG); Device: ARGOS (Movu/Santec; distributed by Alcon)

Detailed Description

One hundred and forty-four eyes of 144 consecutive Thai cataract surgery patients aged 40-90 years presenting with visually significant age-related cataract were enrolled at the Ophthalmology Service, Walailak University Hospital between May 2024 and December 2024. Participants underwent preoperative biometric measurement on the same day with both the ARGOS (software version A2.4; Movu, Inc., a Santec company; distributed by Alcon Laboratories) and the IOLMaster 700 (software version 1.90.10; Carl Zeiss Meditec AG) by a single experienced operator. Participants were randomized 1:1 between two IOL-selection arms using a computer-generated allocation sequence (Research Randomizer, blocks of 12): Group 1 used the IOLMaster 700 with the Barrett Universal II TK formula for IOL power selection, and Group 2 used the ARGOS with the standard Barrett Universal II K formula. Allocation was concealed from the enrolling surgeon until completion of preoperative biometry. Participants were masked to the device-formula arm. All cataract surgeries were performed by four experienced surgeons (in approximately equal numbers) using a standardized phacoemulsification technique with in-the-bag implantation of the TECNIS Monofocal one-piece IOL (model GCB00V; Johnson & Johnson Vision). The primary outcome was mean absolute prediction error (MAE) at one month postoperatively, assessed by a masked refractionist using subjective manifest refraction. Secondary outcomes were median absolute prediction error and the proportion of eyes within ±0.25 D and ±0.50 D of target refraction. One eye per patient was enrolled. The study was registered prospectively as a non-inferiority trial; the implemented analysis is reported as a within-subject paired comparative analysis with descriptive accuracy thresholds rather than as a formal non-inferiority hypothesis test (CONSORT item 3b). The total enrolled sample was 144 patients; within-subject paired analyses included 138 eyes with complete data for both devices.

• Study Type: Interventional
• Enrollment (Actual): 144
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Thailand
  • Changwat Nakhon Si Thammarat
    • Nakhon Si Thammarat, Changwat Nakhon Si Thammarat, Thailand, 80160
      • Walailak University

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Adults aged 40-90 years presenting with visually significant age-related cataract scheduled for elective phacoemulsification with implantation of a TECNIS Monofocal one-piece IOL (model GCB00V).

Exclusion Criteria:

• Corneal astigmatism greater than 1.00 D on either device
• Central corneal thickness outside 490-600 µm
• Severe dry eye precluding reliable keratometry
• Rigid or soft contact lens wear within 2 months prior to evaluation
• Previous corneal refractive surgery or other corneal pathology
• Prior intraocular surgery (other than uneventful cataract surgery in the fellow eye)
• Clinically significant retinal pathology potentially affecting refractive outcome (e.g., epiretinal membrane, diabetic macular edema, advanced age-related macular degeneration)
• Intraoperative complications including posterior capsule rupture, vitreous loss, or zonular dehiscence
• Dense cataract that does not allow measurements with optical biometry
• Inability to attend follow-up

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: IOLMaster 700; Patients allocated to this arm underwent biometric measurement with the IOLMaster 700 swept-source OCT biometer (Carl Zeiss Meditec AG). IOL power for the implanted TECNIS Monofocal one-piece IOL (model GCB00V) was calculated using the Barrett Universal II formula with total keratometry input (Barrett UII TK	Device: IOLMaster 700 (Carl Zeiss Meditec AG); Preoperative biometric measurement using the IOLMaster 700 (software version 1.90.10). IOL power was calculated using the Barrett Universal II TK formula and used for power selection in this arm.
Experimental: ARGOS; Patients allocated to this arm underwent biometric measurement with the ARGOS swept-source OCT biometer, which uses segmental refractive indices for axial length measurement. IOL power for the implanted TECNIS Monofocal one-piece IOL (model GCB00V) was calculated using the standard Barrett Universal II formula with anterior keratometry input (Barrett UII K	Device: ARGOS (Movu/Santec; distributed by Alcon); Preoperative biometric measurement using the ARGOS (software version A2.4). IOL power was calculated using the Barrett Universal II K formula and used for power selection in this arm.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Mean absolute prediction error	Mean absolute prediction error determining by the absolute disparity between the predicted spherical equivalent refraction derived from preoperative planning and the actual measured spherical equivalent refraction (manifest) from both devices (IOLMaster 700 and Argos)	4 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Proportion of eyes with absolute prediction error ≤ 0.25 D	Percentage of eyes in which the absolute prediction error (|measured SE - predicted SE|) was within ±0.25 D of the target refraction at one month postoperatively, for each device-formula pairing.	4 weeks
Median absolute prediction error	Median of the absolute differences between predicted spherical equivalent refraction (derived from preoperative biometry and IOL formula) and the actual measured spherical equivalent (manifest refraction) at one month postoperatively, for both devices (IOLMaster 700 with Barrett UII TK and ARGOS with Barrett UII K)	4 weeks
Proportion of eyes within ±0.50 D of target refraction	Percentage of eyes in which the absolute prediction error was within ±0.50 D of the target refraction at one month postoperatively, for each device-formula pairing.	4 weeks

Collaborators and Investigators

• Sponsor: Walailak University

Study record dates

Study Major Dates

• Study Start (Actual): May 1, 2024
• Primary Completion (Actual): January 31, 2025
• Study Completion (Actual): January 31, 2025

Study Registration Dates

• First Submitted: January 30, 2024
• First Submitted That Met QC Criteria: April 16, 2024
• First Posted (Actual): April 22, 2024

Study Record Updates

• Last Update Posted (Actual): May 15, 2026
• Last Update Submitted That Met QC Criteria: May 12, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: Biometry; SS-OCT; IOLMaster700; Argos
• Additional Relevant MeSH Terms: Eye Diseases; Lens Diseases; Cataract
• Other Study ID Numbers: WU66290 (Other Grant/Funding Number: Walailak individual grant)

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No