Revealing Intraocular Lens Unfolding Dynamics In Porcine Eyes At Body Temperature: A Visual Exploration

 Observing the unfolding of the intraocular lens (IOL) within the capsule is important to penetrate the mechanisms underlying postoperative toric IOL rotation. To address this, we developed an experimental setup to visualize IOL unfolding in extracted porcine eyes, meticulously maintaining body temperature conditions. Through analysis of recorded videos, differences of IOL behavior from insertion into the lens capsule to its fixation was observed using three IOL models.

Department of Ophthalmology, Tokyo Dental College Suidobashi Hospital

 Porcine eyes were securely affixed in an aluminum holder on a heated breadboard, maintaining a temperature of 36 degrees centigrade to mimic physiological conditions. Complete removal of the iris facilitated entire observation of the capsule. Following anterior capsulotomy, phacoemulsification and aspiration, IOL was inserted into the capsule. Three IOL models (PODFGF from BVI Medical, XY1-SP from HOYA, and CNL0T0 from Alcon) were inserted in each porcine eye. IOL unfolding dynamics were scrutinized under a surgical microscope, both from a frontal perspective and at a 45-degree angle. The imaged of microscopy were recorded.

 Frontal microscopic observation revealed dynamic unfolding of the entire IOL within the capsule. In eyes implanted with PODFGF, rapid unfolding of the optic and double C-loop haptics was observed upon release from the injector. Conversely, in eyes receiving XY1-SP and CNL0T0, gradual unfolding of the optic and leading haptic were noted, with the trading haptics exhibiting delayed stretching compared to the leading haptic. Manipulation with a hook was necessary in XY1-SP eyes to expedite stretching of the trading haptic. From a 45-degree angle, meticulous observation elucidated the process of leading haptic stretching to reach the lens equator. The haptic loop made contact with the lens equator, showcasing distinct fixation patterns.

 The experimental system successfully facilitated observation of IOL unfolding, closely mirroring the clinical setting of cataract surgery. Removal of the iris enabled comprehensive visualization of the entire IOL from a frontal perspective. Additionally, observing from a 45-degree angle allowed precise assessment of the leading haptic's interaction with the lens equator. Notably, variations in IOL unfolding and fixation patterns were evident across different IOL models, highlighting the system's versatility. This experimental setup would support the evaluation of IOL stability, particularly in assessing toric IOL rotation.