Effectiveness of PKP vs DSAEK in Terms of 2-year Postoperative Visual Acuity in Advanced BPK

Bullous pseudophakic keratopathy (PBK) is the development of irreversible corneal edema after cataract surgery. Since approximately 20 million people worldwide undergo cataract surgery annually, and PBK can occur in 1-2% of cataract operations, PBK remains a major indication for corneal transplantation. Indeed, it accounts for a quarter of the 5,000 corneal transplant operations that are conducted in France each year. Penetrating keratoplasty (PKP) involves transplanting a full-thickness corneal button. It was the only corneal transplant technique available for PBK until 2004-2006, when two posterior lamellar corneal transplantation methods were invented and refined, namely, Descemet stripping automated keratoplasty (DSAEK) and Descemet membrane endothelial keratoplasty (DMEK). Both have transformed the management of PBK and are often preferred over PKP because of faster visual improvement and fewer complications, including astigmatism and graft rejection. This is particularly true for cases where preoperative visual acuity is better than 2/10 (0.7 logMAR). However, PKP is still indicated when visual acuity is below the ability to see hand movements (2 logMAR): in such cases, the severe stromal damage requires full-thickness transplantation. However, for PBK cases with intermediate visual acuity (i.e. between 0.7 and 2 logMAR), there is doubt about the best therapeutic solution. The relatively severe corneal damage in these cases is a contraindication for DMEK, which is a much more technically challenging procedure than DSAEK. Thus, the surgeon must choose either DSAEK or PKP. DSAEK is suitable for older people who mainly complain of eye pain: it is a simple and painless procedure that leads to satisfactory outcomes in 75% of cases. However, in the remaining 25% of patients, ocular pain may persist and/or the recovery of visual acuity is too limited and the patient is dissatisfied. In such cases, the patient is indicated for regraft with PKP. Given the poor visual outcomes of DSAEK for a substantial minority of patients with preoperative visual acuity between 0.7 and 2 logMAR, the present study asks whether PKP should be the primary choice for such patients. To improve decision-making for PBK, the study also asks whether it is possible to define preoperative visual acuity and/or central corneal thickness (CCT) thresholds that signal a high risk of regraft after primary DSAEK and therefore indicate a need for primary PKP.

• Visual acuity [Time frame: at 6, 12, and 24 postoperative months (repeated measures model)]
• Time taken to achieve a postoperative best corrected visual acuity of at least 4/10 (0.4 logMAR). [Time frame: up to 24 postoperative months]
• Percentage of patients achieving at least 4/10 (0.4 logMAR) [Time frame: up to 24 postoperative months]
• Frequency of cases who require a regraft [Time frame: up to 24 postoperative months]
• Change in quality of life at 12 and 24 months relative to preoperative baseline [Time frame: 1 to 6 months before surgery and at 12 and 24 postoperative months]
• Patient satisfaction [Time frame: at 1, 6, 12, and 24 postoperative months relative to preoperative baseline.]
• Pain level [Time frame: at 1, 6, 12, and 24 postoperative months relative to preoperative baseline]
• Complication number and types [Time frame: within 24 postoperative months]
• Corneal endothelial cell density [Time frame: at 6, 12, and 24 postoperative months.]
• Required optical correction [Time frame: at 6, 12 and 24 postoperative months]
• Emerging adverse events and serious adverse events [Time frame: with the 24 postoperative months]
• Change in central corneal thickness [Time frame: at 6, 12 and 24 months relative to preoperative baseline]