Paul M. Phillips

Precut Tissue for Descemet's Stripping Automated Endothelial Keratoplasty: Vision, Astigmatism, and Endothelial Survival

PURPOSE To report 6 and 12 month results using precut tissue for Descemets stripping automated endothelial keratoplasty (DSAEK) and correlate donor characteristics with clinical outcomes. DESIGN Prospective, noncomparative, interventional case series. PARTICIPANTS We reviewed 100 donor corneas precut for 100 eyes of 90 DSAEK patients. METHODS Our first 100 consecutive cases of DSAEK with precut tissue were entered into a prospective protocol. Donor characteristics and the visual, refractive, topographic, and specular microscopy results at 6 and 12 months were analyzed. Correlation analysis comparing donor characteristics with clinical outcomes was performed. MAIN OUTCOME MEASURES Six- and 12-month postoperative best spectacle-corrected visual acuity (BSCVA), refractive astigmatism, topographic keratometry (K), and specular endothelial cell densities (ECD) were measured prospectively and then compared with preoperative values. Donor characteristics analyzed included death to preservation time, death to surgery time, precutting resection to surgery time, and graft thickness. RESULTS Six months after DSAEK surgery, BSCVA improved from 20/83 to 20/38. (P<0.01). In eyes with no known comorbidity (n = 60), 92% had a vision of >/=20/40 at 6 months and 20% obtained > or =20/20. Astigmatism changed an average of 0.09 diopters (D) and K changed by +0.09 D, both of which were not significant and were stable to 12 months. The postoperative mean ECD (n = 65) was 1918 cells/mm(2) at 6 months, and represented a 31% cell loss from preoperatively (P<0.001). The mean ECD (n = 61) was 1990 cells/mm(2) at 12 months, and represented a 29% cell loss from preoperatively (P<0.001) with no significant change from 6 to 12 months (P = 0.172). Improvement of visual acuity from preoperative to postoperative in eyes without comorbidity was not correlated with any donor characteristic. Greater endothelial cell loss correlated with higher preoperative ECD levels (P<0.001) and with a trend toward longer precut resection to surgery times at both 6 months (P = 0.049) and 12 months (P = 0.051). CONCLUSIONS Precut tissue by Eye Banks for use in DSAEK surgery provides an improvement in vision with no significant change in astigmatism. Donor endothelial cell loss from 6 to 12 months is stable and is comparable with reports involving tissue that is cut intraoperatively. FINANCIAL DISCLOSURE(S) Proprietary or commercial disclosures may be found after the references.

Endothelial keratoplasty: the influence of insertion techniques and incision size on donor endothelial survival.

Purpose: To determine the acute endothelial cell damage from trephination and tissue insertion in endothelial keratoplasty (EK) surgery. The influence of insertion technique (forceps insertion vs “pull-through” insertion) of donor tissue and incision size (3 vs 5 mm length) was assessed. Methods: Forty precut 8.-mm-diameter donor posterior buttons were used in this study. Thirty-five buttons were inserted through a limbal incision of either 3 or 5 mm length into the anterior chamber of cadaver eyes and then removed through an open sky technique without further trauma. Five buttons that were trephined but not inserted served as a control group. Vital dye staining and computer digitized planimetry were used to analyze the tissue and quantify the total damaged area over the entire endothelial surface. Five buttons for each of 7 insertion techniques were used. The 8 tissue groups evaluated were as follows: group 1: control group of trephination only, with no insertion; group 2: forceps with folded tissue through 5-mm incision; group 3: suture pull through of nonfolded tissue through a 5-mm incision; group 4: forceps pull through of Busin glide folded tissue through a 5-mm incision; group 5: forceps with folded tissue through a 3-mm incision; group 6: suture pull through with folded tissue through a 3-mm incision; group 7: suture pull through with nonfolded tissue through a 3-mm incision; and group 8: forceps pull through of Busin glide folded tissue through a 3-mm incision. Results: The control group demonstrated 9% ± 2% peripheral cell damage from simple trephination of the tissue but without insertion. In the 5-mm incision surgeries, forceps insertion (group 2) caused 18% ± 3% loss, suture pull-through insertion (group 3) caused 18% ± 2% loss, and Busin glide pull through (group 4) caused 20% ± 5% loss. There were no significant differences in damage between any of the 5-mm incision group techniques (P > 0.99). In the 3-mm incision surgeries, forceps insertion (group 5) caused a 30% ± 3% loss, pull through with folded tissue (group 6) caused 30% ± 5% loss, pull through with nonfolded tissue (group 7) caused 56% ± 4% loss, and Busin glide pull through (group 8) caused a 28%± 5% loss. There was no difference in damage among the 3-mm groups (P > 0.96), with the exception of group 7 where pulling the unfolded tissue through a 3-mm incision was significantly worse than all other techniques (P < 0.001). There was significantly greater cell area damage in the 3-mm groups (36%) than in the 5-mm groups (19%) (P <0.001). Large patterns of striae with cell loss were seen in the 3-mm groups emanating from the peripheral traction site, regardless of whether the traction to pull the tissue through the incision and into the chamber was generated by a suture or cross-chamber forceps. Direct forceps insertion caused circular patterns of injury at the tip compression site regardless of incision size, but this damage was multiplied and exacerbated by insertion through a smaller incision. Conclusions: Smaller size (3 mm) incisions for EK surgery result in greater acute endothelial area damage than larger size (5 mm) incisions. Pull-through insertion techniques through a 5-mm incision seem equivalent in the amount of induced area damage to that of forceps insertion. Compressive injury from the incision appeared less when the tissue was folded than when not folded. Insertion with any technique through a 3-mm incision resulted in larger areas of endothelial damage. All these iatrogenic death zones outside the central endothelial area would be missed clinically by standard early specular microscopy after EK surgery.

Descemet stripping automated endothelial keratoplasty in eyes with previous trabeculectomy and tube shunt procedures: intraoperative and early postoperative complications.

Purpose: To evaluate the intraoperative and early postoperative outcomes of Descemet stripping automated endothelial keratoplasty (DSAEK) in patients with previous glaucoma filtering surgeries. Methods: A retrospective review of all DSAEK surgeries performed at one center comparing complications of DSAEK in eyes with previous glaucoma filtering procedures (study eyes) with a time-matched group of all other DSAEK cases (control eyes). Results: There were 28 study eyes, 19 with previous trabeculectomies and 9 with previous glaucoma drainage devices (GDDs) and 431 control eyes. Study group intraoperative complications included 1 compromised bleb and 1 loss of donor tissue because of traumatic manipulation. One intraoperative complication, a perforation of the donor tissue, occurred in the control group. Venting stab incisions were used more often in study eyes (n = 5; 18%) than in control eyes (n = 12; 4.4%) (P = 0.002). GDD tubes were trimmed in 2 eyes (22%). No intraoperative manipulations were used to occlude the glaucoma filters or tubes. Postoperative complications in the study group included 1 dislocation (3.6%) and 1 decentered graft (3.6%) and 1 eye with loss of pressure control (3.6%), whereas in the control group, there were 10 dislocations (2.3%) and 1 decentered graft (0.2%) (P = 0.267 for dislocations and P = 0.118 for decentered grafts). One episode of pupillary block (0.2%) occurred in the control group, and none occurred in the study group. No primary graft failures occurred in either group. Conclusions: DSAEK surgeries in eyes with previous glaucoma filtering procedures were performed without primary graft failure and with reasonably low dislocation (3.6%) and graft decentration (3.6%) rates. Although the intraoperative complication rate for the study group (7.1%) was higher than the rate for the control group (0.23%), excellent early postoperative outcomes can be achieved when DSAEK is performed in eyes with previous trabeculectomies and GDDs.

Endothelial Keratoplasty: Vision, Endothelial Survival, and Complications in a Comparative Case Series of Fellows vs Attending Surgeons

PURPOSE To compare a 6-month postoperative vision, endothelial cell loss, and immediate postoperative complications in Descemet stripping automated endothelial keratoplasty (DSAEK) cases performed by an experienced corneal surgeon and his inexperienced fellows using an established technique. DESIGN Retrospective analysis of prospectively gathered data in 327 consecutive DSAEK cases. METHODS DSAEK cases performed by fellows vs attending surgeons during a concurrent period were compared for 6-month postoperative best spectacle-corrected visual acuity (BSCVA), endothelial cell loss, and immediate postoperative complications. This series represents the initial consecutive cases performed by 3 cornea fellows using a technique identical to that used by the attending. RESULTS After DSAEK, average BSCVA improved from 20/80 to 20/37 in the attending cases and 20/74 to 20/36 in the fellow cases. There was no statistical difference in endothelial cell loss between groups (32% vs 35%). The dislocation rate was 2% in the attending group and 1% in the fellow group. There were no primary graft failures or cases of pupillary block in either group. CONCLUSIONS This study demonstrates no difference in vision or endothelial cell loss after DSAEK when performed by an experienced corneal surgeon or inexperienced fellows. Postoperative complications also were similar. Results and complications of DSAEK performed by supervised novice fellows can equal those of an experienced DSAEK surgeon.

Descemet stripping endothelial keratoplasty: six-month results of the first 100 consecutive surgeries performed solo by a surgeon using 1 technique with 100% follow-up.

Purpose: To determine the outcomes and complication rates achieved by a novice cornea surgeon when performing Descemet stripping automated endothelial keratoplasty (DSAEK) while precisely following a previously described forceps insertion technique. Methods: Prospective, noncomparative interventional case series including 100 eyes of 74 patients with endothelial decompensation. An institutional review board approved, prospective, DSAEK series was initiated. Cases included all initial patients with endothelial failure operated on by a single surgeon after his cornea fellowship training. The surgeon strictly adhered to a previously published 5-mm incision, folded forceps graft insertion technique. Patients were followed at 1 day, 1 week, and 1, 3, and 6 months. Postoperative complications (including graft dislocation, primary graft failure, and pupillary block), best spectacle-corrected visual acuity (BSCVA) and specular microscopy of central endothelial cell density at 6 months postoperatively were the main outcome measures. Results: One hundred consecutive eyes were enrolled in the study, and 100% follow-up at 6 months was achieved. Postoperative complications included 2 graft dislocations (2%), and both grafts were attached successfully and cleared; 2 episodes of cystoid macular edema (2%) occurred, and 1 eye (1%) developed areas of anterior iris synechiae to the graft. There were no pupillary block episodes or primary graft failures. In eyes without comorbidity (n = 57), the mean BSCVA improved from 20/48 preoperation to 20/29 at 6 months after operation (P < 0.001). No eyes lost vision. Mean central endothelial cell density decreased from 2769 cells per square millimeter preoperatively to 2308 cells per square millimeter postoperatively at 6 months. This represented a mean cell loss of 16%. Conclusions: This study demonstrates that with meticulous attention to a standardized forceps insertion technique, excellent outcomes with low rates of complications, improved BSCVA, and low endothelial cell loss can be achieved with DSAEK surgery.

Complications and Clinical Outcomes of Descemet Stripping Automated Endothelial Keratoplasty With Intraocular Lens Exchange

PURPOSE To evaluate complications and clinical outcomes of Descemet stripping automated endothelial keratoplasty (DSAEK) with intraocular lens (IOL) exchange compared with DSAEK alone. DESIGN Retrospective, interventional case series. METHODS DSAEK was performed in 19 eyes in which the anterior chamber IOL was exchanged for a posterior chamber IOL (study group) and in 188 eyes in which the posterior chamber IOL was left in place (comparison group). The complications of graft dislocations, primary graft failure episodes, and pupillary block were recorded for all eyes. Six-month best spectacle-corrected visual acuity and mean central endothelial cell density were measured prospectively and then compared with preoperative values for all eyes. RESULTS Dislocations occurred in 0 (0%) of 19 eyes in the study group and in 5 (3%) of 188 eyes in the comparison group (P = .47), with 0 primary graft failures and 0 pupillary block episodes in either group. Preoperative mean best spectacle-corrected visual acuity for those eyes without any underlying ocular comorbidities was 20/205 and 20/100 in the study and comparison groups, respectively (P = .18). Mean best spectacle-corrected visual acuity at 6 months improved to 20/48 in the study group and to 20/34 in the comparison group, a statistically significant difference (P = .01). Mean donor cell loss at 6 months was 33% in the study group and 26% in the comparison group (P = .18). CONCLUSIONS Concurrent IOL exchange with DSAEK surgery does not increase the dislocation, primary graft failure, or pupillary block rates in the immediate postoperative period. Donor endothelial cell loss in DSAEK was not increased significantly by IOL exchange. Visual acuity was slightly worse after combined surgery than after DSAEK alone.

Descemet's stripping automated endothelial keratoplasty (DSAEK) using corneal donor tissue not acceptable for use in penetrating keratoplasty as a result of anterior stromal scars, pterygia, and previous corneal refractive surgical procedures.

Purpose: The purpose of this study was to evaluate outcomes of Descemets stripping automated endothelial keratoplasty (DSAEK) using anterior stromal flawed (ASF) donor corneas that were unsuitable for use in full-thickness penetrating keratoplasty as a result of stromal scars, pterygia, or previous corneal refractive surgery and to compare results with DSAEK using standard tissue. Methods: We conducted a review of our initial 42 (19 with 6-month follow up) consecutive DSAEK surgeries using ASF tissue compared with 357 (199 with 6-month follow up) time-matched controls using standard tissue. Intraoperative and perioperative complications, including dislocations and primary graft failures, were compared. Six-month best spectacle-corrected vision, incidence of rejection episodes, postoperative refractive astigmatism, keratometric values, pre- and postoperative topography-derived surface asymmetry index, and surface regularity index were compared. Results: One surgeon-cut ASF tissue was perforated before surgery and was discarded. No surgeon-cut standard tissue was perforated. No intraoperative complications and no episodes of primary graft failure or pupillary block glaucoma occurred in either group. One (2.4%) postoperative graft dislocation and one (5.2%) graft rejection episode occurred in the study group. There were 10 (2.8%) dislocations and 8 (2.2%) graft rejection in the controls. A statistically similar significant improvement in best spectacle-corrected vision occurred in both groups. Corneal topography, pachymetry, and manifest astigmatism were not significantly different between groups. Conclusion: Postoperative results of DSAEK using donor tissue excluded from use in penetrating keratoplasty as a result of stromal flaws are equivalent to results using standard donor tissue. Central corneal thickness measurements should be performed before cutting to avoid tissue perforation. The use of ASF tissue for DSAEK will expand the cornea donor pool.

Ultrathin DSAEK Tissue Prepared With a Low-Pulse Energy, High-Frequency Femtosecond Laser

Purpose: To evaluate the endothelial cell survival and stromal bed quality when creating deep stromal cuts with a low–pulse energy, high-frequency femtosecond laser to produce “ultrathin” tissue for Descemet stripping automated endothelial keratoplasty. Methods: Seventeen corneas were used for this study. Five corneas were cut with the laser at a depth of 420 to 500 &mgr;m to produce a tissue thickness of approximately ⩽70 &mgr;m. Five corneas served as an uncut comparison group. Vital dye staining and computer digitized planimetry analysis were performed on these corneas. The 7 remaining corneas were cut for scanning electron microscopy evaluation. Results: The mean central posterior stromal thickness of cut corneas was 60.6 &mgr;m (range, 43–72 &mgr;m). Endothelial cell damage in cut and comparison corneas was 3.92% ± 2.22% (range, 1.71%–6.51%) and 4.15% ± 2.64% (range, 1.21%–7.01%), respectively (P = 0.887). Low-magnification (×12) scanning electron microscopy revealed a somewhat irregular-appearing surface with concentric rings peripherally. Qualitative grading of higher magnification (×50) central images resulted in an average score of 2.56 (between smooth and rough). Conclusions: Ultrathin tissue for Descemet stripping automated endothelial keratoplasty can be safely prepared with minimal endothelial cell damage using a low–pulse energy, high-frequency femtosecond laser; however, the resulting stromal surface quality may not be optimal with this technique.

Endothelial cell damage in descemet stripping automated endothelial keratoplasty with the underfold technique: 6- and 12-month results.

Purpose: To evaluate the endothelial cell loss at 6 and 12 months after Descemet stripping automated endothelial keratoplasty (DSAEK) using a modified 40/60 underfolding technique and to compare this to the literature on other commonly used implantation techniques, such as the conventional 60/40-fold, gliding, and hitch suture techniques. Methods: Endothelial cell density was measured prospectively, and cell loss was calculated at 6 and 12 months after endothelial keratoplasty using a recently described underfolding implantation technique. Results: In this study, 305 eyes undergoing DSAEK were evaluated. Average endothelial cell loss was 26% at 6 months and 27% at 12 months, all statistically significant reductions from preoperative values (P < 0.01). The decrease in cell count from 6 months to 12 months was not statistically significant. Conclusions: This study demonstrates reduction in endothelial cell loss after DSAEK using the underfold technique when compared with previous reports on conventional folding techniques and similarity to previous reports on glide techniques at 6 and 12 months postoperatively (26% vs. 34% vs. 23% at 6 months). This offers an easy modification to a commonly used existing technique and improves endothelial cell survival after DSAEK.

Descemet-stripping automated endothelial keratoplasty: insertion using a novel 40/60 underfold technique for preservation of donor endothelium.

Purpose: To describe a technique for insertion of an asymmetrically folded donor graft to minimize endothelial damage during Descemet-stripping automated endothelial keratoplasty. Methods: The tissue is folded in a 40/60 underfold rather than the commonly used 60/40 overfold. It is then grasped with the insertion forceps by using a prone hand position. The hand is rotated clockwise until it is supine, bringing the 60% side of the fold anteriorly, and then the tissue is inserted into the anterior chamber. Results: In 112 eyes, conventional 60/40 overfold insertion technique resulted in a 36% loss in endothelial cell density at 6 months. In 36 eyes, the new 40/60 underfold technique results in a 26% cell loss. This difference of 10% was statistically significant (P = 0.001). Conclusions: This simple modification to a commonly used folding technique reduces trauma to the exposed peripheral endothelium in a 60/40 overfolded “taco,” which is due to contact with the donor trephine block or other surface. It is a slight modification to a commonly used technique for graft insertion and can be easily implemented to reduce postoperative endothelial cell loss.