Clinical Ophthalmology (Aug 2023)
Intraocular Lens Unfurling Time Exponentially Decays with Increased Solution Temperature
Abstract
Erick E Rocher,1 Rishima Mukherjee,1 James Pitingolo,1 Eli Levenshus,1 Gwyneth Alexander,1 Minyoung Park,1 Rupsa Acharya,1 Sarah Khan,1 Jordan Shuff,1 Andres Aguirre,1 Shababa Matin,2 Keith Walter,3 Allen O Eghrari4 1Center for Bioengineering Innovation and Design, Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA; 2Rice 360 Institute for Global Health Technologies, Rice University, Houston, TX, USA; 3Department of Ophthalmology, Wake Forest Baptist Health, Winston-Salem, NC, USA; 4Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USACorrespondence: Allen O Eghrari, Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins University School of Medicine, 400 N Broadway, Smith 5013, Baltimore, MD, 21231, USA, Email [email protected]: Intraocular lens (IOL) unfurling can be a rate-limiting step in cataract surgery, limiting operative efficiency. Furthermore, inefficient unfurling has important implications for clinical outcomes. We examine the effects of solution temperature on IOL unfurling time using three in vitro models of the ocular environment.Methods: IOLs were injected into a 6-well plate filled with balanced salt solution (BSS), dispersive ophthalmic viscoelastic device (OVD), or cohesive OVD. Experiments were also performed in a plastic eye filled with dispersive or cohesive OVD. IOL unfurling time was recorded against the temperature of the respective solution.Results: IOL unfurling time decayed exponentially as solution temperature increased in all experiments, including the BSS-filled 6-well plate, the OVD-filled 6-well plate, and the OVD-filled plastic eye. IOLs failed to unfurl within 10 min at 10°C, below the glass transition temperature of the tested IOLs. Increasing solution temperature from 20°C to 30°C decreases IOL unfurling by greater than 2 min. Further heating to 40°C did not significantly decrease IOL unfurling time.Conclusion: Increased solution temperature rapidly decreases IOL unfurling time in vitro. IOLs do not unfurl within a clinically acceptable timeframe at or below their glass transition temperature. Increased BSS and/or OVD temperature may be a potential method to decrease IOL unfurling time in cataract surgery. However, future research is needed to elucidate potential consequences of warmed BSS and/or OVD on post-operative outcomes. This study demonstrates the potential for temperature regulation to decrease cataract surgery operative time and provides preliminary evidence to justify future clinical validation of this relationship.Plain Language Summary: During cataract surgery, a prosthetic intraocular lens (IOL) is inserted into the eye once the clouded lens is removed. The IOL must then unfurl before the procedure can proceed. When IOLs fail to unfurl or unfurl slowly, this can delay the operation and may even cause post-operative complications. Thus, we studied the effect temperature may have on IOL unfurling time to optimize this segment of the operation.We injected IOLs into solutions of saline (balanced salt solution) or ophthalmic viscoelastic device (OVD), two fluids injected into the eye during surgery. In both a well plate and a plastic eye, we found that increasing the temperature of the solution significantly affected IOL unfurling time. Specifically, heating the solution from refrigeration to room temperature decreased unfurling time from over 10 min to less than four. Heating to physiological temperature further decreased unfurling time to less than a minute.Our results show promise for potentially utilizing heated BSS and/or OVD to accelerate IOL unfurling and decrease cataract surgery operative time.Keywords: cataract surgery, balanced salt solution, ophthalmic viscoelastic device
