Q&A: Peripheral vision IOL's influence on driving performance

As cataract surgery continues to deliver excellent restoration of central visual acuity, a growing body of evidence suggests that the story doesn't end at the fovea. Pseudophakic eyes are known to exhibit increased peripheral refractive errors compared with phakic eyes—errors that can degrade contrast sensitivity, motion perception, and hazard detection at the eccentricities most relevant to real-world activities like driving. A new driving simulator study provides direct functional evidence that reducing those peripheral optical errors translates into measurably faster pedestrian detection and shorter stopping distances, positioning peripheral vision as an emerging frontier in IOL design and patient counseling.

To explore these questions, Modern Retina spoke with the research team behind a prospective simulator study comparing a standard monofocal IOL with a novel peripheral vision IOL designed to reduce peripheral refractive errors. The study's authors include Sara El Aissati, PhD, Roy Reints, PhD, Antonio DelAguila-Carrasco, PhD, Carmen Canovas Vidal, PhD, Christopher Reeves, Johan Le Brun, and Julien Adrian, PhD.

Editor’s note: This interview was conducted via email and was lightly edited for style and clarity.

Why does peripheral vision matter for driving safety, and why hasn't it been a primary focus of IOL design?

Authors: Peripheral vision is critical for driving because many hazards are first detected outside the central line of sight. While driving, the driver typically fixates on the road ahead, the lane, or the tangent point of a curve, while pedestrians, cyclists, or vehicles may initially appear in the peripheral field. Peripheral vision therefore supports early hazard detection, motion awareness, spatial orientation, and timely responses before an object reaches central vision.^1–4

Peripheral vision has not traditionally been a primary focus of intraocular lens (IOL) design for several reasons. First, cataract surgery outcomes have historically been evaluated primarily based on the restoration of central visual acuity. Central acuity is easy to measure clinically, strongly associated with everyday tasks such as reading and object recognition, and remains the main endpoint in routine clinical practice. However, as highlighted in the literature, visual acuity alone is only weakly associated with crash involvement, whereas peripheral vision appears to play a more critical role.⁵ However, pseudophakic eyes exhibit increased peripheral refractive errors compared with phakic eyes.^6,7 These peripheral optical errors have been shown to affect key visual functions, including detection, contrast sensitivity, and motion perception^8–13—abilities that are essential for daily activities such as driving.^14,15 Despite this, peripheral optical quality has been less explored, and its relationship with real-world functional outcomes has not been well established. As a result, there has been limited evidence to guide IOL design toward optimizing peripheral vision.

Our study addresses this gap by demonstrating that reducing peripheral optical errors leads to measurable functional benefits in a driving-relevant task. These findings support that IOL design should not only preserve excellent central vision but also include peripheral optical errors as an important contributor to functional performance, particularly for activities such as driving where early hazard detection is critical.

How did you design the driving simulator to isolate peripheral vision’s contribution, and what steps were taken to minimize confounding variables?

Authors: The simulator task was designed so that the pedestrian hazard initially appeared in the peripheral visual field rather than directly in central vision. Participants drove through curved rural-road scenarios under mesopic/dusk conditions at a constant speed of 70 km/h, and pedestrians were presented at approximately 40 degrees eccentricity at curve entry. As the vehicle followed the curve, the pedestrian moved gradually toward central vision, allowing us to measure when the participant first detected the target. To reduce confounding from central fixation or visual search behavior, participants performed a secondary central letter-reading task at the tangent point of the road. This encouraged them to keep their gaze directed toward the driving path rather than actively scanning for the pedestrian. The response was recorded using steering-wheel paddles, and the main endpoints were reaction time and angles to pedestrian detection.

PV IOL patients detected pedestrians 0.56 seconds earlier than those with standard IOLs—what does that half-second difference actually mean on the road?

Authors: A reduction of 0.56 seconds in reaction time is meaningful in a driving context. Driver reaction time—defined as the interval between the presentation of a hazard and the participant’s response—is one of the most widely used performance metrics in driving safety research.¹⁶ It is a well-established indicator of a driver’s ability to perceive and respond to unexpected events on the road.^17,18 Importantly, reaction time directly influences the distance a vehicle travels before breaking. At a speed of 70 km/h, an improvement of 0.56 seconds corresponds to approximately 11 meters of reduced stopping distance, which can be critical for avoiding a collision. Therefore, the TECNIS monofocal peripheral vision (PV) IOL group (JJVision) would react approximately 11 meters earlier than the TECNIS monofocal IOL group (JJVision).

Aspheric IOL technology also made use of driving simulation to demonstrate the functional benefit of correcting corneal spherical aberration. In fact, a similar reduction of reaction time of 0.5 seconds was obtained with the TECNIS IOLs compared with spherical IOLs. According to a study by the Potomac Institute for Policy Studies, located in Arlington, Virginia, the enhanced vision of patients who receive aspheric IOLs will result in a decrease of 10% in the rate of automobile accidents. Anticipated savings could exceed $1 billion per year, with a prevention of more than 70,000 personal injuries annually.¹⁹

This is why reaction time is a relevant functional endpoint for driving: even sub-second improvements can correspond to several meters of travel distance, especially at typical road speeds, which has a major impact on improving driving performance and safety on the road.

Detection events clustered most frequently between 18–26 degrees of eccentricity. Why is that range significant for driving, and does it point to an optimal “sweet spot” for IOL designers to target?

Authors: When we reviewed published driving studies¹ that reported peripheral target angles and detection eccentricities, the highest concentration of reported was observed between 19° and 24° eccentricities. This closely aligns with the range identified in the present study, where pedestrian detection occurred most frequently within an interval of 18° to 26° eccentricity. In our driving simulator data, this primary detection range indicates that participants typically became aware of the hazard before it reached central vision, when it entered a functionally useful peripheral zone—approximately 20° to 30° of eccentricity, and not beyond that eccentricity. This agreement between our experimental findings and the literature strengthens the interpretation that this range of eccentricities represents a functionally relevant peripheral zone for driving.

In the same study, del Aguila et al²⁰ reported a reduction of peripheral astigmatism with the TECNIS monofocal PV IOL as compared to the non-PV version of 0.85D and 2.49D at 20 and 30 degrees, respectively. That reduction led to the improvement in reaction time in the same range of functionally relevant eccentricities, supporting the concept that this reduction of peripheral astigmatism, especially in this range, has meaningful real-world implications.

Cataract patients vary widely in age, comorbidities, and driving habits—how generalizable are these simulator findings to the broader pseudophakic population?

Authors: Driving simulators are widely used to study driving behavior in standardized and safe environments without exposing participants to real-world risks.^21–23 In ophthalmic research, their use is well established. As mentioned earlier, driving simulation was used to compare the aspheric TECNIS IOL with a spherical acrylic control lens.

In addition, driving simulators are incorporated into established testing standards, such as the ANSI Z80.12-2007 (R2017)²⁴ for multifocal IOLs (MIOLs). The purpose of these functional performance tests is to determine whether optical effects associated with MIOLs lead to clinically meaningful deficits in functional vision under challenging conditions, including night driving and headlight glare.

Together, the current study and previous evidence highlight the value of driving simulation as a tool to link optical design features—such as correction of spherical aberration, multifocality, and reduction of peripheral refractive errors—to real-world functional outcomes relevant to patient safety.

Why did you anchor your conclusions in NHTSA regulatory precedent, and what does that mean for how ophthalmologists should counsel patients about driving fitness after cataract surgery?

Authors: Reaction time is a well-established human-factors metric in driving safety research, widely used by organizations such as the National Highway Traffic Safety Administration (NHTSA) and in the automotive safety literature. In this field, even relatively small reductions in reaction time are considered meaningful because they can translate directly into increased stopping distance or collision risk. For example, safety technologies implemented in the automotive field have demonstrated measurable benefits with reaction time reductions that are comparable in magnitude to those observed in this study. Center high-mounted stop lamps have been associated with improvements of approximately 0.09–0.11 seconds²⁵, while LED signal enhancements have produced reductions of approximately 0.25–0.35 seconds.^26,27 More advanced driver-assistance systems show even larger effects, with forward collision warning systems improving response times by up to 0.50 seconds^28,29 and lane departure warning systems by approximately 0.38 seconds.^30–33 In this context, the observed 0.56-second reduction in pedestrian-detection reaction time exceeds or is comparable to the improvements achieved by several established automotive safety interventions. This comparison highlights the practical and clinical relevance of the findings, as such gains fall within a range known to produce meaningful improvements in real-world driving safety outcomes.

However, the study does not suggest that ophthalmologists should use IOL type alone to determine driving fitness. Driving fitness after cataract surgery should still be assessed using established clinical factors, such as visual acuity, contrast sensitivity, visual field status, glare symptoms, ocular comorbidities, and patient-reported functional difficulties.

The implication is more complex: restoring central vision is essential, but it may not fully capture the visual demands of driving. Peripheral visual quality may be an additional factor to consider when discussing functional outcomes after cataract surgery, especially for patients who drive frequently or in visually challenging conditions such as dusk, rural roads, or low-contrast environments.

What are the next research priorities—refining peripheral IOL design, developing clinical tools to assess peripheral refractive error, or establishing driving-relevant benchmarks for regulators?

Authors: All three are important and complementary research priorities. Del Aguila et al study²⁰ directly links optical improvements to both visual outcomes and functional performance, demonstrating how reduced peripheral refractive errors can translate into measurable benefits.²⁰ At the same time, our current work is taking the lead on the third priority: establishing driving-relevant functional benchmarks. Rather than relying on arbitrary optical thresholds, there is a need to connect optical performance to meaningful real-world endpoints. Metrics such as hazard detection, reaction time, and stopping-distance interpretation provide a more functionally relevant framework. These outcomes are particularly valuable for regulators, clinicians, and patients because they directly reflect performance in everyday visual tasks, such as driving.

What are the next steps in this research?

Authors: A substantial body of evidence shows that peripheral vision plays a critical role in daily activities such as driving,^1,4 as well as walking and climbing stairs. Furthermore, a reduction of peripheral vision has been associated with reduced driving performance ^[34]and an increased risk of falls.³⁵

In line with this, the next steps in this research should focus on expanding the evaluation of peripheral vision into broader functional assessments that more closely reflect additional real-world daily activities. This includes developing and validating additional testing paradigms—beyond driving simulation—that can capture the impact of peripheral optical errors on mobility, locomotion, and safety in everyday life.

Ultimately, the goal is to build a stronger evidence chain linking IOL optical design to meaningful improvements in real-world functional outcomes and daily activities.

Is there anything else you’d like to add or highlight from the study?

Authors: Del Aguila et al²⁰ has demonstrated that a novel lens design (TECNIS monofocal PV IOL, JJ Vision) reduces peripheral optical errors to reduce reaction time and increase stopping distance as compared to the corresponding non-PV IOL. This work establishes the functional relevance of these outcomes while putting in perspective the results of that study with the existing scientific body of evidence.

It is important to remark that the reduction of peripheral optical errors in the PV IOL design maintains central visual performance. In fact, best-corrected distance visual acuity (BCDVA) and mesopic contrast sensitivity were at the level of the standard aspheric monofocal control IOL (TECNIS monofocal IOL, JJ Vision). Together, these findings suggest that the new lens, which reduces peripheral optical errors, enhances functional driving performance, complementing the well-established benefits of central vision correction provided by current IOLs and building on the functional benefits demonstrated by aspheric IOL technology.

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