Refractive Outcomes Utilizing Two SS-OCT Biometers for IOL Power Calculations

Cataract surgery is one of the most performed surgical procedures globally. The goal of the cataract surgeon is to implant an intraocular lens (IOL) with an appropriate IOL power to compensate for the refractive error and leave the patient emmetropic. The accurate measurement of ocular parameters is therefore critical for the effective calculation of IOL power, which directly impacts postoperative visual outcomes. However, accurate IOL power determination is influenced by several factors, including the measurement techniques employed and the specific biometers used in the process.

Optical biometry has become the gold standard for ocular measurements since the introduction of the IOLMaster (Carl Zeiss Meditec AG, Jena, Germany) in 2001. The IOLMaster 700 utilizes SWEPT Source OCT (SS-OCT) with a wavelength of about 1055 nm to generate a 2D OCT cornea-to-retina cross-section scan of the eye. This allows for the computation of all axial biometry measurements, including axial lengths (AL), central corneal thickness (CCT), anterior chamber depths (ACD), and lens thickness (LT).

A relatively newer biometer, Argos 1.5 is also non-invasive and based on SS-OCT technology for IOL power determination with a similar wavelength of 1060 nm ±10nm. However, the IOLMaster 700 uses a traditional axial length computation approach that relies on a single refractive index whiles Argos 1.5 uses a segmented axial length approach based on multiple refractive indices attributed to each ocular component often referred as True AL.

This study aims to evaluate and compare the potential refractive outcomes and biometric measurements of patients undergoing cataract surgery when using Argos 1.5 versus the IOLMaster 700 with the available formulas on each device. By analyzing these biometric measurements, we aim to uncover insights that could enhance our understanding of how different measurement techniques influence postoperative visual outcomes, ultimately contributing to improved patient care.

Inclusion criteria

• 21 years or older (Adult age)
• Assessed to have Cataract Grade 1 and above per LOCS III or Wisconsin Grading scale in at least one eye.
• Able to comprehend and sign the informed consent form.
• Potential postoperative best corrected distance visual acuity (BCDVA) of 0.3 logMAR or better and targeted post-op refraction to be emmetropia, based on the investigator expert medical opinion.

Exclusion criteria

• No active ocular infection or inflammation
• Unable to fixate due to nystagmus or other eye movement abnormality (e.g., significant strabismus)
• Contraindicated for pupil dilation (e.g., narrow angles, allergies) per medical judgement of the investigator.
• Any ocular disease and/or condition that, in the investigator's clinical judgment, may put the subject at significant risk, may compromise study result or may interfere significantly with the subject's participation in the study.