FemtoLASIK After Descemet Membrane Endothelial Keratoplasty.

PURPOSE: To evaluate the efficacy and safety of femtosecond laser-assisted in situ keratomileusis (FemtoLASIK) to correct the residual refractive error after Descemet membrane endothelial keratoplasty (DMEK). METHODS: This case series study included 7 eyes that underwent FemtoLASIK after a DMEK surgery. The refractive error, uncorrected (UDVA) and corrected (CDVA) distance visual acuities, corneal topography (Sirius, CSO, Italy), and anterior segment optical coherence tomography (Visante, Carl Zeiss-Meditec AG, Jena, Germany) were registered at each postoperative follow-up visit. RESULTS: All surgeries were uneventful, with no intraoperative or postoperative complications. The follow-up time after DMEK (before FemtoLASIK surgery) ranged from 18 to 36 months. The post-FemtoLASIK follow-up period ranged from 12 to 60 months. All cases experienced a significant improvement in UDVA after FemtoLASIK, all of them reaching a postoperative UDVA value ≥20/32. None of the eyes lost lines of CDVA, and 1 case showed a gain of lines of CDVA. In all cases, the refractive error, UDVA, and CDVA values remained stable at their respective postoperative follow-up visits. Furthermore, all topographic and pachymetric parameters were stable at the different postoperative follow-up visits. CONCLUSIONS: Our findings suggest that the residual refractive error after DMEK surgery can be safely and effectively treated with FemtoLASIK.

Human Bone Derived Collagen for the Development of an Artificial Corneal Endothelial Graft. In Vivo Results in a Rabbit Model.

Corneal keratoplasty (penetrating or lamellar) using cadaveric human tissue, is nowadays the main treatment for corneal endotelial dysfunctions. However, there is a worldwide shortage of donor corneas available for transplantation and about 53% of the world's population have no access to corneal transplantation. Generating a complete cornea by tissue engineering is still a tough goal, but an endothelial lamellar graft might be an easier task. In this study, we developed a tissue engineered corneal endothelium by culturing human corneal endothelial cells on a human purified type I collagen membrane. Human corneal endothelial cells were cultured from corneal rims after corneal penetrating keratoplasty and type I collagen was isolated from remnant cancellous bone chips. Isolated type I collagen was analyzed by western blot, liquid chromatography -mass spectrometry and quantified using the exponentially modified protein abundance index. Later on, collagen solution was casted at room temperature obtaining an optically transparent and mechanically manageable membrane that supports the growth of human and rabbit corneal endothelial cells which expressed characteristic markers of corneal endothelium: zonula ocluddens-1 and Na+/K+ ATPase. To evaluate the therapeutic efficiency of our artificial endothelial grafts, human purified type I collagen membranes cultured with rabbit corneal endothelial cells were transplanted in New Zealand white rabbits that were kept under a minimal immunosuppression regimen. Transplanted corneas maintained transparency for as long as 6 weeks without obvious edema or immune rejection and maintaining the same endothelial markers that in a healthy cornea. In conclusion, it is possible to develop an artificial human corneal endothelial graft using remnant tissues that are not employed in transplant procedures. This artificial endothelial graft can restore the integrality of corneal endothelium in an experimental model of endothelial dysfunction. This strategy could supply extra endothelial tissue and compensate the deficit of cadaveric grafts for corneal endothelial transplantation.

Posterior chamber collagen copolymer phakic intraocular lens with a central hole to correct myopia: One-year follow-up.

PURPOSE: To assess the predictability, stability, efficacy, and safety of a newly developed posterior chamber phakic intraocular lens (pIOL) (model V4c Visian Implantable Collamer Lens) to correct moderate to high myopia. SETTING: Fernández-Vega Ophthalmological Institute, Oviedo, Spain. DESIGN: Prospective case series. METHODS: This study evaluated eyes that had implantation of the new pIOL model with a central hole for myopia correction. Uncorrected (UDVA) and corrected (CDVA) distance visual acuities, refraction, intraocular pressure (IOP), endothelial cell density, pIOL vault, and adverse events were evaluated over 12 months. RESULTS: The study comprised 147 eyes of 80 patients. Preoperatively, the mean spherical equivalent (SE) was -8.80 diopters (D) ± 2.60 (SD). At 12 months, the mean SE was -0.14 ± 0.26 D, with 93.9% of eyes within ±0.50 D of the target and 100% of eyes within ±1.00 D. The mean UDVA and CDVA were 0.028 ± 0.055 logMAR and 0.003 ± 0.013 logMAR, respectively. The efficacy and safety indices were 1.00 and 1.04, respectively. All eyes had unchanged CDVA or gained 1 or more lines during the follow-up. The IOP remained stable over time; no eye developed anterior subcapsular cataract. Twelve months postoperatively, the mean vault was 405.5 ± 184.7 µm (range 100 to 980 µm), and the mean endothelial cell loss was 1.7%. CONCLUSION: The good refractive and visual acuity outcomes and the highly stable IOP values obtained over 12 months support the use of the new pIOL model with a central hole for the correction of moderate to high myopia. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.

Keratin-chitosan membranes as scaffold for tissue engineering of human cornea.

PURPOSE: To study the attachment and growth of human corneal cells on keratin-chitosan membranes. The end goal is to develop a bioengineered cornea based on this material. METHODS: Keratin-chitosan membranes were prepared as previously described by Tanabe et al., 2002. Briefly, 7.15 mg/cm2 of keratin dialysate was mixed with 10 wt% chitosan solution and 20 wt% glycerol. The solution was cast into a silicone mold and dried at 50ºC for 36 hours. Eyes were attained from a local eye bank after penetrant-keratoplastic surgery. Human epithelial, stromal and endothelial cells were obtained of the limbal, stromal and endothelial regions. Cells were cultured on keratin-chitosan membranes, as well as on plastic dishes as controls. When cultured cells reached confluence, they were fixed, incubated with primary antibodies (E-cadherin, cytokeratin high molecular weight (CK), vimentin and Na+/K+ ATPase) and visualized by indirect immunocytochemistry. RESULTS: Epithelial, stromal and endothelial cells were able to attach and grow on keratin-chitosan membranes. All the cells maintained their morphology and cellular markers, both in the membrane and on the culture plate. Epithelial cells stained positively for CK and E-cadherin. A positive vimentin stain was observed in all stromal cells, while endothelial cells were positive for vimentin and Na+/K+ ATPase, but negative for E-cadherin. CONCLUSIONS: Keratin-chitosan membranes have been shown to be a good scaffold for culturing epithelial, stromal and endothelial corneal cells; therefore, future applications of keratin-chitosan membranes may be developed for reconstruction of the cornea.

Multicenter study of descemet membrane endothelial keratoplasty: first case series of 18 surgeons.

IMPORTANCE: Surgeons starting to perform Descemet membrane endothelial keratoplasty (DMEK) should be informed about the learning curve and experience of others. OBJECTIVE: To document the clinical outcome of standardized "no-touch" DMEK and its complications during the learning curves of experienced surgeons. DESIGN, SETTING, AND PARTICIPANTS: Retrospective multicenter study. A total of 431 eyes from 401 patients with Fuchs endothelial dystrophy (68.2%) and bullous keratopathy (31.8%) underwent DMEK performed by 18 surgeons in 11 countries. EXPOSURES: Descemet membrane endothelial keratoplasty. MAIN OUTCOMES AND MEASURES: Best-corrected visual acuity (BCVA), endothelial cell density, and intraoperative and postoperative complications. RESULTS: Of 275 eyes available for BCVA pooled analysis, BCVA improved in 258 eyes (93.8%), remained unchanged in 12 (4.4%), and deteriorated in 5 (1.8%). Two hundred seventeen eyes (78.9%) reached a BCVA of at least 20/40 (≥0.5), 117 (42.5%) at least 20/25 (≥0.8), and 61 (22.2%) at least 20/20 (≥1.0). Eyes with at least 6 months of follow-up (n = 176) reached similar BCVA outcomes. Mean (SD) decrease in endothelial cell density at 6 months was 47% (20%) (n = 133 [P = .02]). Intraoperative complications were rare, including difficulties in inserting, unfolding, or positioning of the graft (1.2%) and intraoperative hemorrhage (0.5%). The main postoperative complication was graft detachment (34.6%); 20.4% underwent a single rebubbling procedure, occasionally requiring a second (2.6%) and a third rebubbling (0.7%), and 17.6% underwent a second keratoplasty. CONCLUSIONS AND RELEVANCE: Our multicenter study showed that the standardized no-touch DMEK technique was feasible in most hands. The main challenges for surgeons starting to perform the procedure may be (1) to decide whether graft preparation is outsourced or performed during surgery, (2) to limit the number of graft detachments and secondary procedures, and (3) to obtain organ cultured donor corneal tissue.

Identifying causes for poor visual outcome after DSEK/DSAEK following secondary DMEK in the same eye.

PURPOSE: To identify causes of reduced visual acuity after Descemet stripping (automated) endothelial keratoplasty (DSEK/DSAEK) and to determine whether such eyes can be successfully 'repaired' with a secondary Descemet membrane endothelial keratoplasty (DMEK). METHODS: Twelve eyes of 12 patients, who underwent secondary DMEK to manage poor visual outcome after initial DSEK/DSAEK, were evaluated with biomicroscopy, Pentacam imaging, and specular and confocal microscopy, before and at 1, 3 and 6 months after DMEK. RESULTS: Four causes of reduced optical quality of the transplanted host cornea could be identified in DSEK/DSAEK: five eyes (42%) showed large host-Descemet remnants within the visual axis during surgery; six eyes (50%) irregular graft thickness; six eyes subtle 'stromal waves'; and nine eyes (75%) high reflectivity at the donor-to-host interface. After DMEK graft replacement, all corneas cleared and achieved a best corrected visual acuity of ≥20/25 (≥0.8), except for one with a partial Descemet graft detachment. Pachymetry values decreased from 670 (±112) µm before to 517 (±57) µm after secondary DMEK. Higher-order aberrations (Coma and Trefoil) at the posterior surface tended to be lower (p = 0.07) in DMEK grafts than in DSEK/DSAEK grafts. CONCLUSION: Host-Descemet remnants at the donor-to-host interface, interface reflectivity, graft thickness irregularity and donor stromal contraction may contribute to poor visual outcome after DSEK/DSAEK, without causing permanent host corneal damage, as in most cases, complete visual recovery could be achieved by performing a secondary DMEK.

Outcomes of Descemet membrane endothelial keratoplasty in phakic eyes.

PURPOSE: To determine the clinical outcomes of isolated Descemet membrane transplantation (ie, Descemet membrane endothelial keratoplasty [DMEK]) in phakic eyes. SETTING: Tertiary referral center. DESIGN: Cohort study. METHODS: Phakic eyes from a larger group of consecutive eyes that had DMEK for Fuchs endothelial dystrophy were examined. The examination included corrected distance visual acuity (CDVA), subjective and objective refractions, endothelial cell density (ECD), and intraoperative and postoperative complications at 1, 3, and 6 months. RESULTS: The study enrolled 52 phakic eyes from a group of 260 DMEK eyes. Of the phakic eyes, 69% reached a CDVA equal to or better than 20/40 (≥0.5) within 1 week and 85% reached equal to or better than 20/25 (≥0.8) at 6 months. Compared with an age-matched control group of pseudophakic eyes, phakic eyes had a similar visual rehabilitation rate, final visual outcome, mean ECD at 6 months (1660 cells/mm(2) ± 470 [SD]), minor hyperopic shift (+0.74 diopter), and graft detachment rate (4%). Visual acuity equal to or better than 20/13 (≥1.5) was limited to phakic eyes, suggesting better optical quality with the crystalline lens in situ. Temporary mechanical angle-closure glaucoma due to air-bubble dislocation behind the iris was the main complication (11.5%). Two eyes (4%) required phacoemulsification after DMEK. CONCLUSIONS: In phakic eyes, DMEK may give excellent visual outcomes without an increased risk for complications. Visual acuities equal to or better than 20/13 (≥1.5) may indicate that the almost anatomic repair after DMEK is associated with near perfect optical quality of the transplanted cornea. FINANCIAL DISCLOSURE: Dr. Melles is a consultant to D.O.R.C. International/Dutch Ophthalmic USA. No author has a financial or proprietary interest in any material or method mentioned.

Causes of glaucoma after descemet membrane endothelial keratoplasty.

PURPOSE: To describe the incidence and causes of glaucoma after Descemet membrane endothelial keratoplasty (DMEK). DESIGN: Nonrandomized prospective cohort study at a tertiary referral center. METHODS: The incidence of glaucoma was evaluated in the first 275 consecutive eyes that underwent DMEK for Fuchs endothelial dystrophy (260 eyes) or bullous keratopathy (15 eyes). Glaucoma was defined as a postoperative intraocular pressure (IOP) elevation of ≥24 mm Hg, or ≥10 mm Hg from the preoperative baseline. If possible, the cause of glaucoma was identified, and best-corrected visual acuity (BCVA), endothelial cell density (ECD), and postoperative course were documented, with a mean follow-up of 22 (± 13) months. RESULTS: Overall, 18 eyes (6.5%) showed postoperative glaucoma after DMEK. Seven eyes (2.5%) had an exacerbation of a pre-existing glaucoma. Eleven eyes (4%) presented with a de novo IOP elevation, associated with air bubble-induced mechanical angle closure (2%), steroid response (0.7%), or peripheral anterior synechiae (0.4%), or without detectable cause (0.7%). Two eyes (0.7%) required glaucoma surgery after DMEK. At 6 months, all eyes had a BCVA of ≥20/40 (≥0.5), and 81% reached ≥20/25 (≥0.8) (n = 16); mean ECD was 1660 (± 554) cells/mm(2) (n = 15) (P > .1). CONCLUSION: Glaucoma after DMEK may be a relatively frequent complication that could be avoided by reducing the residual postoperative air bubble to 30% in phakic eyes, applying a population-specific steroid regime, and avoiding decentration of the Descemet graft. Eyes with a history of glaucoma may need close IOP monitoring in the first postoperative months, especially in eyes with an angle-supported phakic intraocular lens.

Incidence and causes of ocular surgery cancellations in an ambulatory surgical center.

PURPOSE: To report the incidence and analyze potentially preventable causes of ocular surgery cancellations. SETTING: Ambulatory Care Surgical Center of the Massachusetts Eye and Ear Infirmary, Boston, Massachusetts, USA. METHODS: A retrospective review of the ambulatory surgical center cancellation records and patient medical records from December 2001 to December 2003 was conducted. The primary statistical analysis was conditional logistic regression. RESULTS: Three hundred seventy-nine of 7153 (5.3%) ambulatory ophthalmic surgeries were cancelled within 24 hours of the scheduled start time. Cancellation rates varied by patient age, with the rate among children being highest (8.7%) and that among older patients (age 60+) lowest (4.9%; P = .08). Surgeons who performed at least 4 surgeries per month on average had the lowest cancellation rate (P = .08). Cancellations occurred less frequently in warmer months (June, 3.3%; August, 4.2%) than during the rest of the seasons (P<.001). The highest incidence of cancellations occurred in February (7.8%) and the lowest in June (3.3%). Of the total causes, 41% were considered "preventable," 45% "unpreventable," and 14% "no reason given." Cancellations deemed preventable were lower in general anesthesia cases (1.0%) than in local anesthesia cases (2.0%; P = .02). Preventable cancellation rates also varied by procedure and were statistically significant. CONCLUSIONS: Among ambulatory ophthalmic surgeries, there was a higher incidence of late cancellations in pediatric cases. Late cancellation rates were highest in cases scheduled in the winter, especially in February. Of the reasons documented for cancellations, 41% were considered "preventable" with proper preoperative counseling and instructions. The costs of late cancellations to the particular institution are estimated to be at least $100 000 per year, or nearly 1 month of scheduled surgeries in a 2-year period.