Lauro Augusto de Oliveira

Silk fibroin as a biomaterial substrate for corneal epithelial cell sheet generation.

PURPOSE To evaluate a silk fibroin (SF) biomaterial as a substrate for corneal epithelial cell proliferation, differentiation, and stratification in vitro compared with denuded human amniotic membrane (AM). METHODS Primary human and rabbit corneal epithelial cells and immortalized human corneal limbal epithelial cells were cultured on the SF and denuded AM, respectively. The biological cell behavior, including the morphology, proliferation, differentiation, and stratification, on the two substrates was compared and analyzed. RESULTS Corneal epithelial cells can adhere and proliferate on the SF and denuded AM with a cobblestone appearance, abundant microvilli on the surface, and wide connection with the adjacent cells. MTT assay showed that cell proliferation on denuded AM was statistically higher than that on SF at 24 and 72 hours after plating (P = 0.001 and 0.0005, respectively). Expression of ΔNp63a and keratin 3/12 was detected in primary cell cultures on the two substrates with no statistical difference. When cultured at the air-liquid interface for 7 days, cells on SF could form a comparable stratified graft with a 2- to 3-cell layering, which compared similarly to AM cultures. CONCLUSIONS SF, a novel biomaterial, could support corneal epithelial cells to proliferate, differentiate, and stratify, retaining the normal characteristic epithelium phenotype. Compared with AM, its unique features, including the transparency, ease of handling, and transfer, and inherent freedom from disease transmission, make it a promising substrate for corneal wound repair and tissue-engineering purposes.

Microbiota evaluation of patients with a Boston type I keratoprosthesis treated with topical 0.5% moxifloxacin and 5% povidone-iodine.

Purpose: To evaluate the efficacy of a prophylactic regimen of daily topical 0.5% moxifloxacin and 5% povidone–iodine (PI) in patients with Boston type I keratoprosthesis (KPro) and to assess the applicability of a novel molecular diagnostic technique to analyze the ocular surface microbiota in these patients. Methods: Ten patients had their inferior conjunctival fornix sampled for standard culture methods before the addition of topical 5% PI to the prophylactic regimen and were considered the control group (group 1). The inferior conjunctival fornix and the KPro–donor cornea interface of 10 patients treated with the mentioned prophylactic regimen were sampled and analyzed by standard culture methods and using a polymerase chain reaction/electrospray ionization mass spectrometry assay (group 2). Results: Samples from the inferior conjunctival fornix were positive for coagulase-negative staphylococcus in 3 patients and for Aerobasidium pullulans in 1 patient in group 1. The inferior conjunctival fornix and the KPro–donor cornea interface scrapings were positive for coagulase-negative staphylococcus in 2 patients and 1 patient, respectively, in group 2. No bacteria and fungi growth were detected in any patient from group 2 with the molecular diagnostic approach. None of the patients with culture-positive results developed keratitis or endophthalmitis during the study. Conclusions: Topical 0.5% moxifloxacin associated with topical 5% PI is an effective prophylactic regimen in patients with Boston type I KPro. The molecular diagnostic approach using serial polymerase chain reaction and mass spectrometry was comparable with standard microbiologic techniques as a surveillance tool in these patients.

Boston type 1 keratoprosthesis outcomes in ocular burns.

Purpose:  To report the outcomes of Boston type I keratoprosthesis (BKPro) in the management of ocular burn injuries.

Boston type I keratoprosthesis: Review

Regardless of significant progress in the field of corneal transplantation to treat corneal opacification, some cases of corneal blindness still present a poor prognosis for conventional penetrating keratoplasty. In patients with repeated graft failure and/or with severe ocular surface disease, the Boston type I keratoprosthesis (type I BKPro) has become a viable option. Modifications in its design and postoperative management have improved the long-term outcomes of visual acuity, retention, and postoperative infection rates. These advances made the type I BKPro be considered a safe alternative for visual rehabilitation in many patients with corneal pathologies. However, postoperative handle of chronic comorbidities, such as glaucoma, is still critical for preserving the visual gains achieved with BKPro.

Experience with Boston keratoprosthesis type 1 in the developing world

OBJECTIVE To report the experience of the Federal University of São Paulo, Brazil, in performing Boston keratoprosthesis type 1 implantation in the developing world. METHODS We analyzed 30 eyes of 30 patients who underwent Boston type 1 keratoprosthesis surgery between 2008 and 2012 in a prospective interventional study. Preoperative, perioperative, and postoperative parameters were analyzed, including visual acuity (VA), keratoprosthesis stability, and postoperative complications. RESULTS Preoperative diagnoses were failed grafts in 16 eyes (53.33%), chemical injury in 10 eyes (33.33%) and Stevens-Johnson syndrome in 4 eyes (13.33%). Also, 16 eyes (53.33%) had preoperative glaucoma. Preoperative best corrected VA ranged from 20/400 to light perception. With an average follow-up of 32 months (range 1-55 months), postoperative vision improved to >20/200 in 24 eyes (80%). Postoperative VA was statistically improved compared with the preoperative measurement during all postoperative follow-ups (up to 36 months). During the follow-up period (32 months), retention of the initial keratoprosthesis was 93.3%. The incidence of retroprosthetic membrane was 26.66%. Progression of glaucoma occurred in 7 of 16 eyes (43%). Three patients experienced development of glaucoma after keratoprosthesis implantation. One eye experienced development of infectious keratitis, and 2 eyes had retinal detachment. CONCLUSIONS Performing Boston type 1 keratoprosthesis in a developing country is a viable option after multiple keratoplasty failures and conditions with a poor prognosis for keratoplasty. Our experience appears similar to major reports in the field from investigators in developed countries. Adjustments to postoperative management must be considered according to the particular location.

Infectious keratitis in patients undergoing Boston Type 1 keratoprosthesis (Boston KPro) procedure: case series

Description of two cases of infectious keratitis in patients after Boston Type 1 keratoprosthesis (Boston KPro) implantation. The first case refers to a patient that had the device indicated due to limbal deficiency secondary to severe dry eye who presented a fungal infection by Aerobasidium pullulans that was successfully treated with amphotericin B eye drops. The second case reports a patient with Boston KPro implantation due to previous corneal transplant rejection showing bacterial keratitis in the fourth postoperative month. The etiologic agent was identified as Streptococcus sp and topical treatment with vancomycin was effective. The importance of postoperative surveillance in Boston KPro eyes is discussed.

Distrofia corneana amorfa posterior: relato de caso

The purpose of this paper is to warn the ophthalmologist about the possibility of facing rare cases of corneal dystrophies. Clinical findings of a case of posterior amorphous dystrophy were correlated with refraction, topography, and ultrasound biomicroscopy.

Keratoprosthesis in the fight against corneal blindness in developing countries

hy should we attempt to develop keratoprostheses (KPros) for corneal blindness when standardcorneal transplantation is so well established and relatively safe? It is true that penetrating kera-toplasty, or variations thereof such as endothelial keratoplasty or deep anterior lamellar keratoplasty,are often effective measures in the surgical management of corneal opacification from various causes.However, there are at least two reasons why we need a viable alternative beyond such standard measures.One is due to widespread shortage of donor material and health resources in general, and the other - moreimportant - is the failure rate of keratoplasty in severe cases. Thus we need a back up procedure that can succeedwhen keratoplasty has failed - and particularly so in the Developing World with its high incidence of cornealdisease.According to recent studies, the World Health Organization (WHO) estimates that the global number ofpeople who are considered blind is 39 million

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.

Are cutaneous hypersensitivity tests to inhalant allergens a severity marker for vernal keratoconjunctivitis

PURPOSE The purpose of this study was to analyze the cutaneous sensitivity to a variety of allergens in patients with vernal keratoconjunctivitis (VKC) and to demonstrate the relation between skin response and clinical aspects of the disease. METHODS Twenty patients with vernal keratoconjunctivitis were randomly chosen from the External Disease and Cornea Sector. They were clinically evaluated, and a score ranging from 0 to 20 was applied based on signs and symptoms on ophthalmic examination. All subjects underwent a skin prick test against standardized allergens, such as house dust mites D. pteronyssinus, D. farinae, and Blomia tropicalis, as well as allergens from cat, dog, fungi and feather. RESULTS Seventy-five per cent of patients were positive for at least one of the allergens tested. House dust mites were responsible for the majority of the cases (75%). There was a poor correlation between the clinical score and sensitivity to allergens (r= - 0.119 for fungi; r= - 0.174 for dog; r= - 0.243 for house dust mites; r= - 0.090 for feather). A significant correlation was found only for cat allergen extract (r = - 0.510; p=0.024). CONCLUSIONS Our study demonstrated poor correlation between cutaneous hypersensitivity tests and clinical findings in patients with vernal keratoconjuntivitis. We concluded that skin response to inhalant allergens is not a useful test to identify clinical severity and chronicity of inflammatory process in this disease.