Deep Anterior Lamellar Keratoplasty Using Dehydrated versus Standard Organ Culture-Stored Donor Corneas: Prospective Randomized Trial.

PURPOSE: To compare the outcomes of deep anterior lamellar keratoplasty (DALK) using dehydrated versus standard organ culture-stored donor corneas for eyes with keratoconus. DESIGN: Prospective, randomized, single-center trial conducted in Italy. PARTICIPANTS: Adult patients (age ≥ 18 years) with keratoconus scheduled for elective DALK. METHODS: Patients undergoing successful type 1 bubble pneumatic dissection using a standard DALK technique were randomized during surgery to receive either dehydrated (n = 30) or standard organ culture-stored (n = 30) donor corneas. MAIN OUTCOME MEASURES: The primary study outcome was best spectacle-corrected visual acuity (BSCVA) 12 months after surgery. Secondary outcomes were refractive astigmatism (RA), endothelial cell density (ECD), and complication rates. RESULTS: Postoperative BSCVA did not significantly differ between groups at both time points: mean difference at 6 months was 0.030 logarithm of the minimum angle of resolution (logMAR; 95% confidence interval [CI], -0.53 to 0.10 logMAR; P = 0.471) and at 12 months was -0.013 logMAR (95% CI, -0.10 to 0.08 logMAR; P = 0.764). No significant differences between groups were observed in terms of postoperative RA and ECD at all time points. In the first 3 days after DALK, an epithelial defect was present in 10 patients (33%) in the organ culture cornea group and in 29 patients (97%) in the dehydrated cornea group. Complete re-epithelialization was achieved by day 7 in all patients (100%) in both groups. CONCLUSIONS: The study provides evidence that the use of dehydrated corneas is noninferior to the use of standard organ culture donor corneas for DALK. Corneal tissue dehydration represents a viable solution that can allow long-term cornea preservation and avoid wastage of unused corneas. FINANCIAL DISCLOSURE(S): The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Accuracy of intraocular lens power calculation for cataract surgery after deep anterior lamellar keratoplasty.

BACKGROUND: The purpose of this study was to assess the accuracy of intraocular lens power (IOL) formulas for cataract surgery after deep anterior lamellar keratoplasty (DALK). METHODS: This retrospective study included eyes which had previously undergone DALK and underwent standard phacoemulsification with monofocal IOL implantation between January 2012 and January 2021 at Ospedali Privati Forlì "Villa Igea" (Forlì, Italy). The predicted spherical equivalent (SE) was calculated using the Barrett Universal II, Emmetropia Verifying Optical (EVO), Haigis, Hoffer Q, Hoffer QST, Holladay 1, Holladay II, Kane and SRK/T formulas. Prediction error (PE) was calculated as the actual postoperative SE refraction minus the SE predicted refraction. RESULTS: Eighty-two eyes of 82 patients were included. The mean PE was negative using all formulas. Friedman test revealed a statistically significant difference of the median absolute PE (MedAE) among the different IOL formulas (P = 0.005). On the basis of the MedAE, the formulas were ranked as follows: SRK/T (0.805 D), Kane (0.810 D), EVO (0.845 D), Hoffer QST (0.847 D), Barrett (0.895 D), Holladay 1 (0.915 D), Haigis (1.010 D) and Hoffer Q (1.070 D) formulas. CONCLUSIONS: All formulas had a tendency towards a myopic refractive shift in post-DALK eyes. Although the SRK/T, Kane, EVO and Hoffer QST formulas were more accurate, predictability of refractive outcomes was lower than in virgin eyes.

Culture of corneal endothelial cells obtained by descemetorhexis of corneas with Fuchs endothelial corneal dystrophy.

Currently, endothelial keratoplasty is the gold standard for the surgical treatment of Fuchs endothelial corneal dystrophy (FECD). Despite the remarkable success in terms of surgical outcomes, a shortage of corneal donor tissue poses a limitation to performing endothelial keratoplasty in many parts of the world. Cell therapy is a potential alternative strategy to keratoplasty and is currently under investigation. Considering that corneas with FECD may contain relatively healthy endothelial cells, samples obtained by descemetorhexis of eyes undergoing EK for FECD can be used for ex vivo expansion of endothelial cells as an autologous cell culture. In this study, we established corneal endothelial cell cultures derived from 40 patients that underwent endothelial keratoplasty for advanced FECD. Several parameters were evaluated including patient characteristics such as age, gender, and endothelial cell density as well as various processing and cell culture protocols based on different combinations of shipping temperatures, stabilization periods and treatment methods for corneal endothelial cell dissociation. FECD cultures were classified into three groups as: (i) no cells, (ii) cell cultures with endothelial-like morphology or (iii) cell cultures with fibroblast-like features. Our data seem to suggest that some factors can influence FECD cell culture characteristics including young age, high paracentral endothelial cell density, low shipping temperature and short stabilization period prior to cell isolation. Treatment with type 1 collagenase for cell isolation can delay endothelial-to-mesenchymal transition, but does not increase proliferative capacity. Although heterologous corneal endothelial cultures from healthy donors have shown encouraging outcomes, the feasibility of autologous cell therapy as a potential treatment for FECD remains challenging. Low initial cell concentration as well as endothelial to mesenchymal transition are the main obstacles to the application of FECD cultures in the clinical setting.

Optimizing outcomes for keratoplasty in ectatic corneal disease.

PURPOSE OF REVIEW: Advanced keratectasia often requires corneal transplantation for restoration of vision. This review discusses the surgical approach suitable for these cases including significant updates in the current literature. RECENT FINDINGS: With greater understanding of ectatic corneal disease and its associated operative challenges, several modifications in the surgical approach have been developed. Identified predictive factors for successful pneumatic dissection and intraoperative complications have informed surgical planning and decision-making. In the setting of failed pneumatic dissection, sequential use of alternative lamellar dissection techniques is a reasonable surgical strategy. Surgical refinements to optimize visual outcomes and postoperative interventions to correct residual refractive errors have improved visual rehabilitation after keratoplasty. SUMMARY: With evidence of its undisputed advantages, DALK has been widely recognized as the primary surgical option for ectatic corneal disease.

Large (9 mm) Deep Anterior Lamellar Keratoplasty with Clearance of a 6-mm Optical Zone Optimizes Outcomes of Keratoconus Surgery.

PURPOSE: To evaluate the outcomes of a 9-mm deep anterior lamellar keratoplasty (DALK) with removal of the deep stroma limited to the central 6-mm optical zone. DESIGN: Prospective, noncomparative, interventional case series. PARTICIPANTS: A total of 80 consecutive keratoconic eyes without deep stromal scarring, with at least 1 postoperative examination 1 month after complete suture removal. INTERVENTION: A standardized DALK was performed, including (1) deep trephination of the recipient bed 450 to 550 µm in depth and 9 mm in diameter; (2) pneumatic dissection; (3) debulking of approximately 80% of the anterior stroma; (4) removal of the deep stroma (bubble roof) from a central 6-mm optical zone; and (5) transplantation of a 9-mm anterior corneal lamella cut by microkeratome-assisted dissection (400-µm head) and sutured with a double running 10-0 nylon suture. MAIN OUTCOME MEASURES: Success rate and type of pneumatic dissection obtained; best spectacle-corrected visual acuity (BSCVA), refractive astigmatism (RA), and topographic astigmatism (TA), central corneal thickness (CCT) and endothelial cell density 12 months postoperatively; and intraoperative and postoperative complications. RESULTS: Pneumatic dissection created a "big bubble" in 67 of 80 eyes (83.7%), all of them but 1 (1.5%) being of type 1 according to the classification by Dua et al. After complete suture removal, BSCVA averaged 0.09±0.72 logarithm of the minimum angle of resolution (logMAR) and was ≥20/20 in 28 eyes (35%), ≥20/25 in 54 eyes (67.5%), and ≥20/40 in 76 eyes (95%); RA averaged 3.10±1.30 diopters (D), with 73 eyes (91%) within 4.5 D and none above 6 D; regular TA was detected in 72 eyes (90%); mean CCT was 492±62.10 µm; postoperative endothelial cell density averaged 2026±397cells/mm2 with a mean cell loss of 11.2%. Intraoperative complications included loss of suction (n = 1) and perforation (n = 4). No conversion to penetrating keratoplasty was necessary. After surgery, double anterior chamber was observed in 2 cases (2.5%), both managed successfully by air filling of the anterior chamber. Stromal rejection was observed in 6 eyes (7.5%) and was reversed with topical steroids in all cases. CONCLUSIONS: In keratoconic eyes without deep stromal scars, the combination of a graft larger than conventional ones with limited removal of deep stroma can improve visual and refractive outcomes of DALK, while minimizing the rate of complications.

Contact Lens-Assisted Pull-Through Technique for Delivery of Tri-Folded (Endothelium in) DMEK Grafts Minimizes Surgical Time and Cell Loss.

PURPOSE: To evaluate the feasibility and outcomes of contact lens-assisted bimanual pull-through delivery of Descemet membrane endothelial keratoplasty (DMEK) tissue trifolded with the endothelium inward. DESIGN: Prospective, noncomparative, interventional case series. PARTICIPANTS: Forty-two consecutive eyes of 42 patients with Fuchs endothelial dystrophy with or without cataract. INTERVENTION: Standardized DMEK was performed as a single procedure (n = 9) or in combination with phacoemulsification and implantation of a posterior chamber intraocular lens (n = 33) using prestripped donor tissue punched to a diameter of 8.25 mm and then trifolded with the endothelium in. Using a sterile soft contact lens as scaffold, the tissue was loaded in this configuration into a disposable cartridge and delivered into the anterior chamber under continuous irrigation using a bimanual pull-through technique to facilitate spontaneous proper unfolding. MAIN OUTCOME MEASURES: Surgical time, intraoperative and postoperative complications, visual acuity 3 and 6 months after surgery, and endothelial cell loss 6 months after surgery. RESULTS: Surgery was uneventful in all cases and the time required for the DMEK procedure (from Descemet scoring until final air filling) never exceeded 20 minutes (average, 17.1±1.6 minutes). The only complication observed after surgery was graft detachment (10 of 42 eyes [23.8%]), successfully managed in all cases by single rebubbling within 6 days from surgery. In all eyes with a minimum postoperative follow-up of 6 months (n = 20), best spectacle-corrected visual acuity was 20/25 or better and the average endothelial cell density (±standard deviation) was 2363.8±82.7 cells/mm(2) (range, 2258-2490 cells/mm(2)). The cell loss calculated as a percentage of the preoperative value determined at the eye bank (range, 2500-2700 cells/mm(2)) was 9.9±2.1% (range, 4.1%-11.9%). CONCLUSIONS: Delivering DMEK tissue, trifolded with the endothelium inward, reduces surgical trauma to donor cells and facilitates spontaneous unfolding, thus minimizing surgical time.

Corneal Epithelial Stem Cells Repopulate the Donor Area within 1 Year from Limbus Removal for Limbal Autograft.

PURPOSE: To determine whether limbal epithelial stem cells (LESCs) repopulate the site harvested for limbal autograft transplantation (LAT), the expression of LESCs markers was evaluated in bioptic specimens obtained from the donor area 12 months or more after surgery. DESIGN: Interventional case series. PARTICIPANTS: Patients who underwent LAT for unilateral acquired limbal stem cell deficiency after chemical burn. METHODS: Corneal limbal explants were obtained from 2 sites, the harvested area and the untouched control area, in the donor eyes of 6 patients who previously underwent LAT for unilateral acquired limbal stem cell deficiency after chemical burn. Limbal epithelial stem cells were isolated, and cellular, immunohistochemistry, and histologic parameters were assessed to compare differences between LESCs isolated from harvested or control sites. MAIN OUTCOME MEASURES: Presence of LESCs 1 year or more after LAT. RESULTS: Specific markers (p63, Ki67, K12), percentage of LESCs, cell doubling, and number of passages in culture did not differ significantly between harvested and control sites. However, the distinctive structure of the palisades of Vogt was found only in 2 of 6 harvested sites. CONCLUSIONS: Limbal epithelial stem cells repopulate the donor site as early as 1 year after limbus removal for LAT. Autologous transplantation of conjunctiva and limbus are safe procedures and can be performed in cases that cannot be treated by simple grafting of LESCs cultured ex vivo.

Descemet stripping automated endothelial keratoplasty in Fuchs' corneal endothelial dystrophy: anterior segment optical coherence tomography and in vivo confocal microscopy analysis.

BACKGROUND: To evaluate the in vivo corneal changes using in vivo confocal microscopy (IVCM) and anterior segment optical coherence tomography (AS-OCT) in patients with Fuchs' dystrophy who underwent Descemet stripping automated endothelial keratoplasty (DSAEK) and the relationship between these changes and the postoperative visual recovery up to 1-year follow-up. METHODS: Before DSAEK and 1 day, 3, 6 and 12 months after surgery 31 patients (39 pseudophakic eyes) underwent a complete ophthalmological evaluation including best corrected visual acuity (BCVA), IVCM (subepithelial haze, interface haze, graft thickness) and AS-OCT (graft thickness). RESULTS: Graft thickness measurements by AS-OCT were strongly correlated to those obtained using IVCM at every follow-up stage (intraclass correlation coefficient = 0.95 to 0.97 between 3 and 12 months, P < 0.001 for all coefficients). No correlation between BCVA and graft thickness measured by AS-OCT at any follow-up stage was found, while at 3 and 6 postoperative months the correlations between BCVA and preoperative subepithelial haze (r = 0.61, P < 0.001 and r = 0.46, P = 0.002), interface haze (r = 0.51, P < 0.001 and r = 0.46, P = 0.003), postoperative subepithelial haze (r = 0.43, P = 0.004 and r = 0.39, P = 0.001) were significant. CONCLUSIONS: The study confirmed corneal subepithelial haze and interface haze as important factors limiting visual acuity after DSAEK, while graft thickness was not related to BCVA.

Does thickness matter: ultrathin Descemet stripping automated endothelial keratoplasty.

PURPOSE OF REVIEW: Descemet stripping automated endothelial keratoplasty (DSAEK) has become worldwide the procedure of choice for the replacement of diseased corneal endothelium. More recently, ultrathin DSAEK (UT-DSAEK) has been introduced to guarantee better visual outcomes preserving good donor graft manipulation. RECENT FINDINGS: As DSAEK may still have major challenges such as suboptimal visual acuity and relatively slow visual rehabilitation, fairly new techniques such as UT-DSAEK and Descemet membrane endothelial keratoplasty (DMEK) have been introduced to allow much quicker and optimal visual rehabilitation. This article goes through the most recent findings and results of these techniques. SUMMARY: UT-DSAEK is a procedure that shares the improved visual outcome and lower immunologic rejection rate of DMEK over DSAEK, while minimizing all types of postoperative complications. In addition, similar to DSAEK and unlike DMEK, UT-DSAEK can be performed in all types of eyes, even in those with complicated anatomy or poor anterior chamber visualization.