AC-IOLs: To Remove or Not to Remove? A Critical Look at Endothelial Keratoplasty Outcomes
"Navigating the complexities of managing anterior chamber intraocular lenses (AC-IOLs) during endothelial keratoplasty for optimal patient outcomes."
Endothelial keratoplasty (EK) has revolutionized the treatment of corneal endothelial dysfunction, offering improved visual rehabilitation compared to penetrating keratoplasty. However, the presence of an anterior chamber intraocular lens (AC-IOL) introduces a layer of complexity. The question of whether to remove or retain the AC-IOL during EK remains a topic of considerable debate among surgeons.
A recent letter to the editor sparked renewed discussion on this contentious issue, specifically addressing an article on endothelial keratoplasty in eyes with retained angle-supported intraocular lenses. The core of the debate centers on balancing the potential benefits of AC-IOL removal, such as restoring more natural anterior segment anatomy, against the risks associated with additional surgical manipulation.
This article delves into the arguments surrounding AC-IOL management during EK, examining factors that influence surgical decisions and exploring the impact of AC-IOL retention or removal on graft survival and overall visual outcomes. Understanding these nuances is crucial for surgeons seeking to optimize results and minimize complications in this challenging patient population.
Clinical Importance
Endothelial keratoplasty is an important surgical approach for corneal endothelial disease, but outcomes can depend on the eye’s prior surgery and intraocular lens configuration. In eyes with an anterior chamber intraocular lens, clinicians must weigh potential visual benefits against technical and endothelial risks. The decision to remove or retain the lens therefore requires individualized assessment rather than a uniform rule.
Techniques and Limitations
Published reports describe both Descemet membrane endothelial keratoplasty (DMEK) and Descemet stripping automated endothelial keratoplasty (DSAEK) in eyes with retained angle-supported anterior chamber intraocular lenses. One retrospective case series identified 7 DMEK and 11 DSAEK procedures among 263 consecutive endothelial keratoplasty procedures. Reported concerns include difficult donor insertion and unfolding, problems achieving or maintaining an effective air tamponade, and long-term endothelial cell damage. Another review notes that endothelial cell loss can also occur during IOL removal and that graft detachment, rejection, and failure must be considered when counseling patients.
Evolution of Endothelial Surgery
The development of endothelial keratoplasty reflects a shift toward selectively replacing diseased corneal endothelial tissue rather than routinely replacing the full cornea. DMEK and DSAEK represent established forms of this tissue-selective approach. The historical record also shows that retained anterior chamber lenses created specific technical and biological questions as these procedures evolved.
AC-IOL Removal: Weighing the Pros and Cons
The decision to remove or retain an AC-IOL during EK is not a one-size-fits-all approach. Several factors must be considered, including the AC-IOL's stability, its impact on anterior chamber anatomy, and the patient's overall ocular health. Proponents of AC-IOL removal argue that it restores a more natural anterior segment, potentially leading to improved long-term graft survival.
- Potential Benefits of AC-IOL Removal:
- Restoration of normal anterior segment anatomy
- Reduced risk of endothelial cell damage from AC-IOL contact
- Potential for improved long-term graft survival
- Potential Benefits of AC-IOL Retention:
- Reduced surgical time and invasiveness
- Lower risk of complications associated with IOL exchange
- Faster visual recovery in selected cases
Current Evidence
Recent research continues to examine endothelial keratoplasty outcomes across different indications, lens configurations, and levels of surgical complexity. Current reviews emphasize that results should be interpreted in light of patient and procedure characteristics rather than treated as universally applicable. The evidence base remains dependent on retrospective series and comparative studies in several clinically important settings.
Failure and Alternatives
Comparative research has evaluated endothelial keratoplasty against repeat penetrating keratoplasty after a failed penetrating graft, focusing on graft survival, graft rejection, and visual acuity. A systematic literature review identified randomized clinical trials and comparative cohort studies for this comparison, while a separate publication describes the same clinical question as an area of study. Graft rejection is identified as a major cause of secondary failure, particularly after full-thickness keratoplasty. A 10-year retrospective DMEK case series of 105 patients further examined how surgical indication and procedural complexity relate to long-term outcomes and early signs of graft failure.
Choosing Between Procedures
Comparisons between endothelial keratoplasty and repeat penetrating keratoplasty generally center on graft survival, rejection, and visual acuity. The available evidence suggests that procedure choice is shaped by the condition of the existing graft, the complexity of the eye, and the risks associated with each surgical approach. These comparisons support a case-specific decision rather than assuming that one technique is optimal for every failed corneal graft.
Making the Informed Surgical Decision
The management of AC-IOLs during endothelial keratoplasty requires a nuanced and individualized approach. While the debate regarding removal versus retention continues, a thorough understanding of the potential benefits and risks associated with each strategy is paramount. By carefully evaluating patient-specific factors and employing meticulous surgical technique, surgeons can optimize outcomes and improve the lives of patients undergoing this complex procedure. Further research, particularly long-term studies, will undoubtedly shed more light on this topic and refine surgical decision-making in the future.
Balancing Risks and Benefits
The central clinical question is not simply whether an anterior chamber intraocular lens is present, but how its presence affects surgical access, graft behavior, and endothelial health. Retaining the lens may avoid the endothelial trauma associated with removal, while removal may be considered when lens-related anatomy compromises the procedure. Because the available evidence includes retrospective studies and technically complex cases, individualized counseling remains essential.
Emerging Directions
Endothelial keratoplasty is defined as an umbrella term for selective replacement of the corneal endothelium and adjacent tissue while preserving healthy portions of the patient’s cornea. A bibliometric analysis of research published from 2004 through 2023 identified 2,676 publications and reported a significant increase over time, indicating expanding scientific activity. Artificial intelligence is now being examined in corneal endothelial disease and endothelial keratoplasty, with current work focused on clinical evidence, readiness for practice, and future directions.
System-Level Considerations
Endothelial keratoplasty outcomes are influenced by more than the chosen surgical technique. Patient selection, prior ocular surgery, graft availability, postoperative monitoring, and access to experienced corneal surgeons can all affect real-world care. These broader factors make it difficult to apply findings from specialized studies uniformly across healthcare settings.
Patient-Centered Decisions
For patients with an anterior chamber intraocular lens and corneal endothelial disease, the choice to remove or retain the lens involves balancing surgical complexity against the possibility of future graft problems. Counseling should address the potential need for additional corneal surgery and the uncertainty surrounding outcomes in complex eyes. Shared decision-making is therefore an important part of planning endothelial keratoplasty.