What are the possible reasons for poor unfolding of an implantable collamer lens (ICL) when the first pair of haptics are sticking together despite apparently correct loading?

Poor Unfolding of ICL with Haptics Sticking Together

The most common reason for poor ICL unfolding with haptics sticking together is improper loading technique, specifically inadequate separation of the haptics during cartridge loading or insufficient viscoelastic between the lens surfaces.

Primary Technical Causes

Loading-Related Issues

• Inadequate viscoelastic coating during the loading process can cause haptic surfaces to adhere to each other, preventing proper separation during injection 1
• Improper cartridge loading technique where haptics are not properly separated before folding can result in haptics remaining adherent throughout the injection process 1
• Excessive compression during loading may cause the collamer material to temporarily bond, particularly if the lens surfaces contact each other without adequate lubrication 2

Lens-Related Factors

• Lens material properties of the collamer can become tacky if exposed to air for prolonged periods before loading, increasing surface adhesion 1
• Incorrect lens size selection may contribute to difficult unfolding mechanics, though this typically manifests as vault problems rather than haptic adhesion 3
• Manufacturing variations in lens surface properties, though rare with modern ICLs, can occasionally affect unfolding characteristics 2

Intraoperative Contributing Factors

Surgical Technique Issues

• Insufficient anterior chamber depth or inadequate viscoelastic fill at the time of injection can prevent proper lens expansion 1
• Rapid injection speed may not allow adequate time for viscoelastic to separate the haptic surfaces as the lens enters the eye 1
• Inadequate pupil dilation (for posterior chamber ICL placement) can restrict the space available for lens manipulation and unfolding 4

Environmental Factors

• Temperature variations in the operating room or lens storage can affect the collamer material's flexibility and surface properties 1
• Prolonged time between lens removal from packaging and implantation allows the lens to dry, increasing surface tackiness 1

Prevention Strategies

Pre-Loading Preparation

• Ensure generous viscoelastic coating of all lens surfaces, particularly between haptics, before cartridge loading 1
• Verify proper lens hydration by keeping the lens in balanced salt solution until immediately before loading 1
• Inspect the lens carefully for any manufacturing defects or surface irregularities before loading 2

Loading Technique Optimization

• Deliberately separate haptics during the folding process to ensure viscoelastic is present between all surfaces 1
• Use slow, controlled folding to prevent excessive compression that could cause surface adhesion 1
• Maintain adequate viscoelastic in the cartridge throughout the loading process 1

Intraoperative Management

• Ensure complete anterior chamber fill with cohesive viscoelastic before injection 1
• Use controlled, moderate injection speed to allow proper lens expansion 1
• Have manipulation instruments ready to gently separate haptics if initial unfolding is incomplete 1

Common Pitfalls

• Rushing the loading process is a frequent cause of inadequate haptic separation 1
• Using insufficient viscoelastic to economize can lead to surface adhesion problems 1
• Failing to recognize incomplete unfolding early can lead to improper lens positioning and subsequent complications including lens dislocation/decentration, which accounts for 7% of ICL explantations 4
• Attempting forceful manipulation of stuck haptics can cause endothelial damage or iris trauma 4

Clinical Significance

While haptic adhesion during unfolding is primarily a technical challenge rather than a direct threat to vision, improper lens positioning resulting from incomplete unfolding can lead to serious complications including abnormal vault (contributing to cataract formation in 1-2.3% of cases), lens decentration requiring repositioning or exchange, and endothelial cell loss 4, 1. The incidence of cataract formation with posterior chamber phakic IOLs has been directly linked to surgeon experience, emphasizing the importance of proper surgical technique including lens loading and deployment 4.