Nicolas Cesário Pereira

Endothelial keratoplasty: evolution and horizons

Endothelial keratoplasty has been adopted by corneal surgeons worldwide as an alternative to penetrating keratoplasty (PK) in the treatment of corneal endothelial disorders. Since the first surgeries in 1998, different surgical techniques have been used to replace the diseased endothelium. Compared with penetrating keratoplasty, all these techniques may provide faster and better visual rehabilitation with minimal change in refractive power of the transplanted cornea, minimal induced astigmatism, elimination of suture-induced complications and late wound dehiscence, and a reduced demand for postoperative care. Translational research involving cell-based therapy is the next step in work on endothelial keratoplasty. The present review updates information on comparisons among different techniques and predicts the direction of future treatment.

Limbal transplantation at a tertiary hospital in Brazil: a retrospective study.

PURPOSE Epidemiological analysis of limbal transplantation surgeries performed in the Ophthalmologic Hospital of Sorocaba. METHODS Retrospective medical records review of 30 patients who underwent limbal stem cell transplants between January 2003 and March 2008. Cases involving conjunctival limbal autograft were classified as group I, and those involving conjunctival limbal allograft as group II. RESULTS Two patients were excluded due to incomplete data during postoperative follow-up. Of the total sample of 28 patients, 53.6% constituted group I, whereas 46.4% were included in group II. Males were predominant (67.9%), and right eyes were the most prevalent (67.9%). The mean age was 40.3 years. Unilateral cases accounted for 60.7%. The most frequent pathology causing limbal system failure was chemical burns (53%). The mean length of time from diagnosis to surgery was 11.18 years. The limbal graft and amniotic membrane were associated in 75% of all cases, and tarsorrhaphy in 57.1%. The average follow-up period was 24.84 months. The uncorrected visual acuity improved in 38% of the cases, was unchanged in 28.5%, and deteriorated in 33.3%. There was no persistent epithelial defect in 75% of the patients. The conjunctivalization rate was similar between the groups (53.3% and 58.3%, respectively). The transparency improved in only 38.4% of the cases, and 28.5% of the surgeries performed were successful. The most prevalent complication was persistent epithelial defect, which occurred in 25% of the patients, followed by corneal melting in 14.2%. Other complications observed included infectious ulcers, limbal graft necrosis or ischemia, perforation, and descemetocele. CONCLUSION Chemical burns remain the main cause of limbal stem cell deficiency. In these cases, limbal transplantation is the standard procedure to restore the ocular surface even though the success rate is low.

Principais patógenos e susceptibilidade in vitro antimicrobiana em ceratites bacterianas: Revisão de cinco anos, 2005 a 2009

PURPOSE To determine the most common pathogens involved in the etiology of bacterial keratitis at the Sorocaba Ophthalmological Hospital and the in vitro susceptibility of main antimicrobial used in the treatment of this pathology. METHODS Retrospective study of all patients suspected of infectious keratitis that underwent microbiological exam at the Sorocaba Ophthalmological Hospital, between 2005 and 2009. To test susceptibility of antimicrobial drugs, antibiograms were made through the standard method of discs diffusion and interpretation following the National Committee on Clinical Laboratory Standards (NCCLS, Villanova, PA, USA). RESULTS 963 samples were obtained in this period and 278 (28.86%) were positive for some pathogen. Among the positive for bacteria, the most common were Staphylococcus aureus (30.56%), Staphylococcus epidermidis (30.56%), Streptococcus sp (9.43%) and Pseudomonas sp (9.43%). Dividing in Grams method, 191 (72.08%) were Gram-positive and 74 (27.92%) were Gram-negative. Analyzing in vitro antimicrobial effectiveness, the majority presented good susceptibility rates, beyond 85%, except cephalotin which presented 53.13%. At the same analysis, higher resistance rates with cephalotin (33.47%) and ciprofloxacin (11.36%) were noted. CONCLUSION Gram-positive bacteria were the most common pathogen isolated at microbiologic exams, especially staphylococci. despite the increasing number of isolated Gram-negative bacteria, meanly represented by Pseudomonas, related with the widespread use of contact lenses. Laboratorial exam revealed high sensibility values for most of antibiotics (more than 85%), except for cephalotin (53.13%). Higher resistance values were observed with cephalotin (33.47%) and ciprofloxacin (11.36%). With all these important variability of antibiotic susceptibility and pathogens involved in bacterial keratitis etiology, it is very important to know the specific characteristics of each infection for a better patient care.

Descemet's membrane endothelial keratoplasty with a simplified technique and low complication rate: the samba technique

PURPOSE We report a simplified Descemets membrane endothelial keratoplasty (DMEK) technique that involves safe and effective preparation and introduction, correct orientation, and easy unfolding of the donor graft inside the recipient anterior chamber. METHODS In this retrospective study, we assessed the surgical outcomes of 26 eyes of 23 consecutive patients (mean age, 61.2 ± 11.4 yr; range, 39-82 yr) with Fuchs endothelial corneal dystrophy (n=19) or bullous keratopathy (n=7) who underwent the Samba technique, a simplified DMEK method, at the Sorocaba Ophthalmology Hospital, Sorocaba Eye Bank, Sorocaba, Brazil, between August 2011 and July 2012. RESULTS Of the 26 operated eyes, only two (7.7%) experienced partial graft detachment requiring rebubbling, and in those eyes, the graft was reattached successfully with one air bubble. There were no cases of primary graft failure, tissue loss, or pupillary block. All patients with good visual potential achieved a best-corrected visual acuity of 20/30 or better at 6 months, and 82.6% achieved a best-corrected visual acuity of 20/30 or better 1 month postoperatively. CONCLUSION In this retrospective study, the Samba technique, a simplified DMEK procedure, was safe and effective, with an acceptably low rebubbling rate and no incidence of primary graft failure or pupillary block. Moreover, rapid and nearly complete visual recovery was achieved. This simplified DMEK technique can be adopted by corneal surgeons worldwide as a primary treatment for endothelial dysfunction with a less steep learning curve and low rate of postoperative complications.

Descemet membrane endothelial keratoplasty in multifocal pseudophakic eyes

PURPOSE This report describes the use of Descemet membrane endothelial keratoplasty for the management of endothelial decompensation after multifocal intraocular lens implantation. METHODS In this retrospective study, we reviewed and assessed the surgical outcomes of 9 patients (9 eyes) who underwent Descemet membrane endothelial keratoplasty after multifocal intraocular lens implantation. RESULTS Corneal edema occurred due to Fuchs endothelial corneal dystrophy (n=3), pseudophakic bullous keratopathy (n=3), Descemets membrane detachment (n=2), and toxic anterior segment syndrome (n=1). The Descemet membrane endothelial keratoplasty surgeries were uneventful in all eyes, but rebubbling procedures were necessary in 2 eyes. One month after the surgery, all the corneas were clear. After 6 months, excluding 1 eye with amblyopia, the mean distance corrected visual acuity was 0.10 logMAR, with all eyes achieving 0.18 logMAR or better. CONCLUSIONS This is the first report of Descemet membrane endothelial keratoplasty after multifocal intraocular lens implantation, and it suggests that good results can be achieved without multifocal intraocular lens exchange.

Thickness and immunohistochemistry of LASIK flaps created by different femtosecond lasers in eye-bank corneas

PURPOSE The aim of this study was to compare the corneal cell viability and thickness of LASIK flaps created by 3 femtosecond lasers in eye-bank human corneas. METHODS Forty-five eye-bank human sclerocorneal buttons (15 corneas in each group) were examined after the creation of 120 mm-thick laser-assisted keratomileusis (LASIK) flaps with 150kHz iFS In-traLase™ (IL), Z6 Femto LDV™ (LDV), or 200kHz Wavelight™ FS200 (FS200). The thickness of the flaps was measured using anterior segment optical coherence tomography (AS-OCT; Visante™). Cell viability was blindly evaluated with immunohistochemistry for keratocyte apoptosis using anti-caspase 3 antibodies. RESULTS The standard deviation from the intended flap thickness was less than 10 mm in all the groups. There was a statistically significant difference in corneas treated with LDV and IL with regard to the flap thickness horizontally at +3.00 mm (p=0.0124), -0.5 mm (p=0.0082), and -1.00 mm (p=0.0425) from the corneal vertex and +0.5 mm from the flap edge (p=0.0240), and those treated with LDV and FS200 with regard to the flap thickness horizontally at -0.5 mm from the corneal vertex (p=0.0082). The mean keratocyte apoptosis numbers were 13.09 ± 1.10, 15.59 ± 3.28, and 17.72 ± 1.49 in corneas treated with IL, FS200, and LDV, respectively (p<0.001). CONCLUSION All 3 assessed femtosecond lasers provided predictable LASIK flap thickness. The mean stromal keratocyte apoptosis number was low in all groups.

Endothelial assessment of donated tectonic corneas: a viable option for posterior lamellar transplantation

PURPOSE Donated corneas are classified as tectonic if there are defects within any layers of the cornea which would prevent a satisfactory visual outcome after transplantation. This study aimed to evaluate whether some tectonic corneas have sufficient endothelial characteristics to allow their use in posterior lamellar keratoplasty, and explored their reclassification for use in this sight-improving procedure. METHODS A retrospective review of all corneal tissues preserved by the Sorocaba Eye Bank from January to April of 2014 was performed. All donated corneas classified as tectonic were included. Endothelial tissue was defined as healthy and viable for posterior lamellar keratoplasty if endothelial cell density was ≥2000 cells/mm2. Additional parameters analyzed included Descemet folds and stretch marks, loss of endothelial cells, corneal endothelial polymegathism/ pleomorphism, pseudo-guttata, and reflectivity. RESULTS During the study period, 2,847 corneas were preserved, of which 423 (14.85%) were classified as tectonic. Of these, 87 (20.56%) were reported as having endothelial viability and were included in the posterior lamellar keratoplasty group. Average corneal endothelial cell density of this group was 2,471 SD ± 256 cells/mm2 (range 2012-2967 cells/mm2). CONCLUSION A significant number of corneas classified as tectonic showed endothelial viability and were included in the posterior lamellar keratoplasty group (20.56%). Despite stromal and/or epithelial alterations, these corneas could have been potentially distributed for posterior lamellar transplantation to improve vision, thus reducing the corneal transplantation waiting period. This study highlights how corneal tissue reclassification could increase the potential amount of corneal tissue available for optical transplantation.