Causes of high astigmatism after penetrating keratoplasty

Abstract

We retrospectively evaluated the factors which might have caused excessive corneal astigmatism after penetrating keratoplasty (PKP) in 29 eyes, in which surgical correction of astigmatism was indicated. In 18 eyes high astigmatism (5 diopters or more) existed before suture removal probably due to graft elevation (3x), wound dehiscence (3x), wound configuration abnormalities such as ovality/overcut (8x), and a thin recipient cornea (2x). The cause was unknown in 2 eyes. In 19 eyes the astigmatism considerably increased after all sutures were removed; astigmatism increased an average of 8.8 diopters (range, 5 to 16.5 D). Ten of these 19 patients showed graft elevation, despite the fact that the sutures were only removed after an average 22.9 months. In 3 other patients the astigmatism gradually increased over the years, long after suture removal; two of these showed graft elevation. The study demonstrates the possible instability of keratoplasty wounds, the change in astigmatism after suture removal, and the late apparently spontaneous changes in astigmatism after PKP in some eyes.

Evaluation of different types of lamellar keratoplasty for treatment of peripheral corneal perforation

“…According to recent study results comparing LK and PK, they demonstrated that the amount of postoperative astigmatism was less after LK [19,26]. The lower astigmatism in LK is ascribed to the fact that the residual corneal lamellar bed provides support to maintain the normal corneal curvature during and after surgery, which guarantees that the above corneal graft can be placed and heal in an ideal position without corneal torsion, and suturerelated astigmatism can be avoided to the largest extent as well [27,28]. Compared with the average astigmatism of 5.5 diopters after eccentric PK [11], the astigmatism in our patients was less in semilunar, crescentic, annular and total LK (3.3 to 4 diopters).…”

Experimental Transplantation of Corneal Epithelium-like Cells Induced by Pax6 Gene Transfection of Mouse Embryonic Stem Cells

“…Although allogeneic corneal transplantation has a useful strategy for these diseases, it may be complicated by high irregular astigmatism and corneal graft rejection. 38 It is desirable to establish an alternative method for supplying sufficient cells for reconstruction of the damaged cornea. Recently, autologous limbal stem cell transplantation and tissue-engineered epithelial cell sheets have been developed and have already entered into the clinical realm.…”

Dezentrierung der Spenderhornhaut bei mechanischer und Excimerlaser Trepanation für die perforierende Keratoplastik12

“…Die Ursachen dafür sind vielfältig und ihr Zusammenwirken ist komplex. Während die Nahttechnik vor allem für den Astigmatismus vor Fadenentfernung verantwortlich ist, scheint der persistierende Restastigmatismus nach Fadenentfernung vor allem von der Qualität der Spender-und Empfängertrepanation abzuhängen [2,8,12,13,25,26,27,28,38]. Das Ziel bei der Trepanation ist die Schaffung einer exakt zylinderförmigen Schnittgeometrie bei Spender und Empfänger.…”