Deep suturing technique for penetrating keratoplasty

Angiogenesis and lymphangiogenesis in corneal transplantation-A review

Corneal transplantation has been proven effective for returning the gift of sight to those affected by corneal disorders such as opacity, injury, and infections that are a leading cause of blindness. Immune privilege plays an important role in the success of corneal transplantation procedures; however, immune rejection reactions do occur, and they, in conjunction with a shortage of corneal donor tissue, continue to pose major challenges. Corneal immune privilege is important to the success of corneal transplantation and closely related to the avascular nature of the cornea. Corneal avascularity may be disrupted by the processes of angiogenesis and lymphangiogenesis, and for this reason, these phenomena have been a focus of research in recent years. Through this research, therapies addressing certain rejection reactions related to angiogenesis have been developed and implemented. Corneal donor tissue shortages also have been addressed by the development of new materials to replace the human donor cornea. These advancements, along with other improvements in the corneal transplantation procedure, have contributed to an improved success rate for corneal transplantation. We summarize recent developments and improvements in corneal transplantation, including the current understanding of angiogenesis mechanisms, the anti-angiogenic and anti-lymphangiogenic factors identified to date, and the new materials being used. Additionally, we discuss future directions for research in corneal transplantation.

Corneal Topography-Guided Penetrating Keratoplasty and Suture Adjustment

PURPOSE

To describe a new keratoplasty procedure using intraoperative topography to reduce postoperative astigmatism.

METHODS

One hundred sixty-five eyes of 150 consecutive patients were enrolled in this prospective study. The most common diagnosis was keratoconus (78.8%). As many as 5.5% had post-laser in situ keratomileusis ectasia. Keratoplasty was performed with the Hanna Corneal Trephine System. A 24-bite running suture was placed, using a specially developed marker. Suture adjustment was performed with the aid of an intraoperative topographer (Keratron Scout; OPTIKON 2000, Rome, Italy). The aim of the adjustment was to obtain an astigmatism < or =2.0 D on the operating table. In case of >3.0 D of astigmatism at 1 month after surgery, suture adjustment was performed using the same intraoperative topographer.

RESULTS

At 12 months postoperatevely (suture in), data from 108 (64%) eyes were available. The mean refractive astigmatism was 3.53 D, and the mean topographical astigmatism was 4.7 D. At 18 months (suture out), data from 32 eyes (19.4%) were available, and at 24 months, data from 29 eyes (13.3%) were available. The mean refractive astigmatism was 3.39 D at 18 months and 3.47 D at 24 months. The mean topographic astigmatism was 2.30 D at 18 months and 1.76 D at 24 months. Mean best spectacle-corrected visual acuity (BSCVA) was 0.51 at 3 months, 0.63 at 12 months (suture in), 0.67 at 18 months (suture out), and 0.78 at 24 months postoperatively.

CONCLUSIONS

The combination of intraoperative topography and a 24-bite single running suture resulted in a stable astigmatism throughout the follow-up period, even after suture removal. BSCVA reached a 20/40 level as early as 3 months postoperatively and continued to rise after suture removal. The stability of astigmatism and BSCVA shortened the postoperative visual rehabilitation time and provided a high quality of vision early in the postoperative period.

Comparison of the effect of three suturing techniques on postkeratoplasty astigmatism in keratoconus

PURPOSE

To compare the effect of 3 common suturing techniques on postkeratoplasty astigmatism and final best corrected visual acuity (BCVA) in patients with keratoconus.

METHODS

In this randomized clinical trial, 103 eyes of 103 patients with advanced keratoconus, who were contact lens intolerant, or with contact lens-corrected visual acuity less than 20/80, underwent penetrating keratoplasty with 3 suturing techniques: interrupted (IR), single running (SR), and combined interrupted and running (CIR). Postkeratoplasty astigmatism and BCVA were evaluated during regular examinations 1.5, 3, 6, and 12 months postoperatively and 2 months after complete suture removal. Suture adjustment and selective suture removal were performed 2 to 6 weeks and after 3 months in eyes with more than 4 D of corneal astigmatism in the SR and IR/CIR groups, respectively.

RESULTS

Of 87 patients who completed follow-up, 26 eyes underwent PK with interrupted suturing technique (IR), 26 eyes had single running sutures (SR), and in 35 eyes, the suturing technique was combined (interrupted + running sutures; CIR). Mean age was 27.2 +/- 8.4, 28.9 +/- 8.7, and 30.3 +/- 8.7 years, and postoperative astigmatism 1.5 months after surgery was 3.77 +/- 1.68, 5.48 +/- 2.09, and 4.10 +/- 1.79 D in the 3 groups, respectively (P = 0.015). However, 2 months after complete suture removal, final postoperative astigmatism was 3.83 +/- 1.65, 3.37 +/- 1.9, and 3.88 +/- 2.79 D (P = 0.851) and BCVA (log MAR) was 0.08 +/- 0.14, 0.13 +/- 0.23, and 0.09 +/- 0.16, respectively (P = 0.53). Immunologic endothelial rejection reactions were seen in 5 eyes (19.2%) in the IR group, 3 eyes (11.72%) in the SR group, and 6 eyes (17.64%) in the CIR group (P = 0.44). There was no case of graft failure during the follow-up period.

CONCLUSION

Postkeratoplasty astigmatism and BCVA are comparable with the 3 common suturing techniques (IR, SR, and CIR) in patients with keratoconus, provided that regular postoperative examinations and topography-guided suture adjustment and/or removal are performed.