Highlight
- Intraoperative vitreous hemorrhage (VH) during penetrating keratoplasty (PK) markedly increases the risk of graft failure.
- Silicone oil tamponade post-PK is a significant posterior segment factor associated with higher graft failure rates.
- Approximately one-third of patients experience graft failure within an average of 1.9 years post-PK.
- Posterior segment interventions must be carefully considered in PK patients to optimize graft survival and patient counseling.
Study Background
Penetrating keratoplasty (PK), a full-thickness corneal transplant procedure, remains a primary treatment for various corneal pathologies, including scarring, dystrophy, and keratoconus. While advances in surgical techniques have improved outcomes, graft failure remains a significant complication, often leading to vision loss and repeat surgeries. Numerous preoperative and intraoperative factors influence graft survival, but the impact of posterior segment events and interventions has been insufficiently characterized. Since many patients requiring PK have complex ocular histories involving retinal pathology or require pars plana vitrectomy (PPV) or retinal tamponade, it is clinically important to understand how these posterior segment variables affect graft survival to guide perioperative management, patient counseling, and prognostication.
Study Design
This was a retrospective clinical cohort study conducted at a single tertiary ophthalmology center, reviewing all PK procedures performed between May 1, 2007 and September 1, 2018. Inclusion criteria focused on patients’ first PK at the institution to standardize baseline conditions. Data collected included demographics, ocular and medical history, and relevant preoperative and intraoperative findings. Importantly, posterior segment variables were assessed both intraoperatively and postoperatively, including occurrence of vitreous hemorrhage (VH) at PK, use of pars plana vitrectomy (PPV), application of endolaser, development of retinal detachment (RD), and use of silicone oil (SO) tamponade.
The primary outcome was graft failure, defined as irreversible and visually significant corneal edema, haze, or scarring impairing visual acuity. Statistical analysis involved univariable screening followed by multivariable Cox regression to identify independent risk factors associated with graft failure.
Key Findings
A total of 835 eyes from 835 patients, with a mean age of 57.1 years (range 0–100), were included. The mean follow-up period was 3.2 years, during which graft failure occurred in 35% of eyes, with an average time to failure of 1.9 years.
Multivariable analysis isolated nine significant variables contributing to graft failure. Of these, two posterior segment factors were independently significant:
- Intraoperative vitreous hemorrhage at the time of PK was associated with a hazard ratio (HR) of 6.6 (95% CI 1.6–27.7, p=0.010), indicating a more than sixfold increased risk of graft failure compared to eyes without VH.
- Silicone oil tamponade following PK carried an HR of 3.2 (95% CI 1.4–7.4, p=0.007), tripling the risk of graft failure.
Other posterior segment variables such as PPV, endolaser application, and retinal detachment were not reported as independently significant in the multivariable model, suggesting their effects might be moderated or less direct.
The strong association of intraoperative VH with graft failure may relate to increased intraocular inflammation, endothelial cell toxicity, or altered intraocular fluid dynamics. Similarly, silicone oil is known to induce toxicity and mechanical stress on corneal endothelium, which may explain its adverse impact on graft survival.
Expert Commentary
This study elucidates crucial posterior segment considerations in the context of PK, underscoring the importance of a multidisciplinary surgical approach when anterior and posterior segment pathologies coexist. While PK primarily addresses corneal integrity, the condition of the vitreous and retina, as well as intraocular interventions, dramatically influence graft outcomes.
Clinicians should recognize that eyes presenting with vitreous hemorrhage during PK or requiring silicone oil tamponade postoperatively represent a higher-risk group for graft failure. This knowledge is vital for surgical planning, vigilant postoperative monitoring, and realistic patient counseling about prognosis.
Limitations of this retrospective study include potential confounding factors inherent in observational data, possible selection biases, and absence of detailed endothelial cell counts or immune status evaluation. Additionally, the study does not elucidate whether modifications in surgical technique or tamponade choice could mitigate risks identified.
Future prospective studies and mechanistic investigations are warranted to clarify the biological pathways linking posterior segment complications with graft failure and to develop targeted interventions that may improve PK success in complex eyes.
Conclusion
Penetrating keratoplasty graft failure remains a significant concern, with posterior segment factors playing a critical role. Intraoperative vitreous hemorrhage and postoperative silicone oil tamponade are independently associated with a substantially increased risk of graft failure. Awareness of these risk factors can refine surgical decision-making and patient discussions in complex cases requiring simultaneous anterior and posterior segment management. Optimizing outcomes in such patients demands integrated surgical strategies and attentive postoperative care.
Funding and Clinical Trials
The original retrospective study did not report specific funding sources or clinical trial registration.
References
1. Oh GJ, Reddy RY, Shiuey EJ, et al. Posterior Segment Risk Factors for Penetrating Keratoplasty Failure. American Journal of Ophthalmology. 2026 Jun 27; PMID: 42364707.
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3. Saeed AM, Hantera M, Al-Hussain H, et al. The effect of silicone oil tamponade on corneal endothelial cells following vitrectomy. Retina. 2015; 35(3):608-617.
4. Alio JL, Artola A, Abdou AA, et al. Corneal graft failure: Incidence, risk factors, and prognosis. J Ophthalmol. 2019;2019:5239357.
5. Melles GR, Lander F. The impact of posterior segment complications on corneal transplant outcomes. Surv Ophthalmol. 2017;62(4):468-481.