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Biomedical subjects

A Azuara-Blanco

Publications and source records attributed to A Azuara-Blanco.

At least 37 records · Page 2Linked to original sources
PubMed2000

Protection of corneal endothelium from irrigation damage: a comparison of sodium hyaluronate and hydroxypropylmethylcellulose.

PURPOSE: To compare the endothelial protection of sodium hyaluronate and hydroxypropylmethylcellulose against endothelial damage induced by irrigation. METHODS: An in vitro assay with freshly excised porcine eyes was developed using the Janus green photometry technique. Irrigation and aspiration technique was standardised. Forty pairs of porcine eyes were used. One randomly chosen eye was filled with sodium hyaluronate (SH) and the other with hydroxypropylmethylcellulose (HPMC). Irrigation and aspiration was carried out with balanced salt solution for 5 min. Twenty additional pairs of porcine eyes served as controls. Student's t-test was used for statistical analysis. RESULTS: Both viscoelastic agents protected the endothelium as compared with controls. The endothelial protection, determined with the Janus green photometric technique, was significantly greater with HPMC than with SH. CONCLUSIONS: Viscoelastic agents are effective in protecting the endothelium from irrigation damage in porcine eyes in vitro. HPMC provided greater protection than SH in this particular model.

Animals↗
PubMed2000

Evaluation of corneal endothelium and keratic precipitates by specular microscopy in anterior uveitis.

BACKGROUND: The study of corneal endothelium, by specular microscopy, in patients with anterior uveitis has largely been restricted to observations on the endothelial cells. In this prospective study "keratic precipitates" (KP) in different types of uveitis were examined in different stages of the disease process and the endothelial changes occurring in the vicinity of the KP were evaluated in comparison with the endothelium of the uninvolved eye. METHODS: 13 patients with active unilateral uveitis were recruited. The mean age was 42.9 years (range 20-76 years). A Tomey-1100 contact wide field specular (x10) microscope was used to capture endothelial images and KP until the resolution of uveitis. Data regarding type of uveitis, number, size, and nature of KP were recorded. Automated morphometric analysis was done for cell size, cell density and coefficient of variation, and statistical comparisons of cell size and cell density were made (Student's t test) between the endothelium in the vicinity of fresh and resolving KP, fresh KP and normal endothelium, and resolving KP and normal endothelium. RESULTS: On specular microscopy, fresh KP were seen as dense, white glistening deposits occupying 5-10 endothelial cells in diameter and fine KP were widely distributed and were one or two endothelial cells in diameter. The KP in Posner-Schlossman syndrome had a distinct and different morphology. With clinical remission of uveitis, the KP were observed to undergo characteristic morphological changes and old KP demonstrated a large, dark halo surrounding a central white deposit and occasionally a dark shadow or a "lacuna" replaced the site of the original KP. Endothelial blebs were noted as dark shadows or defects in the endothelial mosaic in patients with recurrent uveitis. There was significant statistical difference in the mean cell size and cell density of endothelial cells in the vicinity of fresh KP compared with normal endothelium of the opposite eye. CONCLUSION: This study elucidated the different specular microscopic features of KP in anterior uveitis. Distinct morphological features of large and fine KP were noted. These features underwent dramatic changes on resolution of uveitis. The endothelium was abnormal in the vicinity of KP, which returned to near normal values on resolution of uveitis.

Adult↗
PubMed2000

Autologous limbal transplantation in patients with unilateral corneal stem cell deficiency.

AIM: To describe a surgical technique for autologous limbal stem cell transplantation and the outcome of a series of patients with unilateral stem cell deficiency. METHODS: A report of six consecutive patients who underwent autologous limbal stem cell transplantation is presented. The primary diagnosis included alkali burn (n=3), conjunctival intraepithelial neoplasia (CIN) (n=1), recurrent pterygium (n=1), and contact lens induced keratopathy (n=1). The autologous transplanted tissue consisted of peripheral cornea, limbus, and conjunctiva obtained from the contralateral eye. Three of the above patients underwent penetrating keratoplasty in association with auto-limbal transplantation. A significant modification to established techniques was the close monitoring of conjunctival epithelial migration in the immediate postoperative period. If conjunctival epithelium threatened to migrate on to the corneal surface, it was mechanically removed at the slit lamp and prevented from crossing the limbus. This was required in three patients. RESULTS: The mean follow up was 18.8 months. The outcome was satisfactory in all cases: a stable corneal surface was restored and there was a substantial improvement in vision and symptoms. One patient had a primary failure of the corneal allograft associated with glaucoma, and 6 months later developed a retinal detachment. No complications were noted in the donor eye with the exception of one patient who developed filamentary keratitis along the edge of the donor site. CONCLUSION: Autologous limbal transplantation with corneal, limbal, and conjunctival carriers was found to be useful for ocular surface reconstruction, over a mid-term follow up, in patients with unilateral stem cell deficiency. Close monitoring of the migration of conjunctival epithelium in the immediate postoperative period, and preventing it from crossing the limbus, ensured that the corneal surface was re-epithelialised exclusively from epithelial cells derived from the transplanted limbal tissue. This approach should improve the success of this procedure.

Adult↗
PubMed2000

Limbal stem cell deficiency: concept, aetiology, clinical presentation, diagnosis and management.

Defects in renewal and repair of ocular surface as a result of limbal stem cell deficiency are now known to cause varying ocular surface morbidity including persistent photophobia, repeated and persistent surface breakdown and overt conjunctivalisation of the cornea. Ocular conditions with abnormalities of ocular surface repair include pterygium, limbal tumours, aniridia, severe scarring following burns, cicatricial pemphigoid and Stevens-Johnson Syndrome, sequelae of mustard gas exposure and Herpes simplex epithelial disease, radiation keratopathy, contact lens induced keratopathy, neuroparalytic keratitis and drug toxicity. Restoring ocular health in these eyes has traditionally been frustrating. An understanding of these intricate cell renewal and maintenance processes has spurred the evolution in recent years of new treatment methods for several blinding diseases of the anterior segment; many more exciting modalities are in the offing. However, there is inadequate awareness among ophthalmologists about the current principles of management of ocular surface disorders. The purpose of this article is to help elucidate the important principles and current treatment methods relevant to ocular surface disorders.

Cell Transplantation↗
PubMed1999

Pseudocapsulorrhexis in a patient with iridocorneal endothelial syndrome.

We describe a patient with Chandler's syndrome variant of the iridocorneal endothelial syndrome in whom ectopic Descemet's membrane was found intraoperatively on the anterior surface of the lens. Initially, the membrane was confused with the anterior lens capsule during extracapsular cataract extraction, leading to the performance of a pseudocapsulorrhexis. Electron microscopy disclosed that the epilenticular membrane was composed of multiple layers of abnormal basement membrane consistent with the iridocorneal endothelial syndrome.

Aged↗
PubMed1999

Malignant glaucoma after diode laser cyclophotocoagulation.

PURPOSE: To report a case of malignant glaucoma after diode laser cyclophotocoagulation. METHOD: Case report. RESULTS: A 45-year-old man with uncontrolled secondary glaucoma in his right eye after corneoscleral graft and cataract extraction underwent diode laser cyclophotocoagulation. The right eye was aphakic, with an intact posterior capsule. Two weeks later, the patient presented with blurred vision, edematous cornea, and flat anterior chamber. The posterior capsule was touching the endothelium. Intraocular pressure was 20 mm Hg. Repeated Nd:YAG laser capsulotomy was effective in reversing the malignant glaucoma attack, and the anterior chamber deepened. CONCLUSION: Malignant glaucoma can occur after diode laser cyclophotocoagulation.

Anterior Chamber↗
PubMed1999

Reversal of optic disc cupping after glaucoma surgery analyzed with a scanning laser tomograph.

OBJECTIVE: To detect and quantitate changes in optic nerve morphology after glaucoma surgery using the Heidelberg Retina Tomograph (HRT, Heidelberg Instruments, Heidelberg, Germany). DESIGN: Nonconsecutive observational case series. PARTICIPANTS AND INTERVENTION: The authors prospectively enrolled 21 adult patients undergoing incisional glaucoma surgery for progressive glaucoma damage. Quantitative analysis of the optic nerve head by scanning laser tomography and automated perimetry were performed before and after glaucoma surgery. MAIN OUTCOME MEASURES: Changes in optic nerve parameters were subjected to linear regression analysis with respect to percent of postoperative reduction of intraocular pressure (IOP), as well as with respect to age, refraction, preoperative cup:disc ratio, and change in visual field parameters. RESULTS: Seventeen patients had pre- and postoperative images suitable for analysis. Mean IOP at the time of image acquisition before surgery was 30.5+/-12 mm Hg, and after surgery 11.8+/-5.2 mm Hg (mean follow-up, 26+/-7 weeks). Eleven of 13 (85%) patients having IOP reduction of greater than 40% showed improvement in optic disc parameters. All four patients with less than 25% reduction in IOP showed worsening of most parameters. Changes in optic disc parameters were highly correlated with percent IOP reduction and with age. The parameters in which change most strongly correlated with percent change of IOP were cup area, rim area, cup:disc ratio, and mean cup depth (each, P<0.005). The age of the patient correlated highly with change in maximum cup depth (P<0.005). Refraction and clinically determined cup:disc ratio correlated poorly with changes in measured optic disc parameters. Clinical improvement in visual fields was correlated with the degree of improvement of cup:disc ratio (P = 0.025). CONCLUSION: Most patients showing a 40% lowering of IOP after glaucoma surgery show improved optic nerve morphology as measured by the HRT. The amount of improvement correlated highly with the percent reduction of IOP.

Adult↗
PubMed1999

Cataract extraction and intraocular lens implantation in anterior megalophthalmos.

This report describes the implantation of a standard posterior chamber intraocular lens (IOL) in a patient with bilateral cataract and anterior megalophthalmos. After extracapsular cataract extraction, the IOL was sutured to the posterior surface of the iris and anterior capsule. Different types of IOLs were used in each eye, and the surgical technique was adapted to the characteristics of the IOL. No complications were noted. Visual rehabilitation was successful. Extracapsular cataract extraction with a posterior chamber IOL sutured to the posterior surface of the iris and anterior capsule is a useful option in patients with anterior megalophthalmos and cataract.

Adult↗
PubMed1999

Pseudo-endothelial dystrophy associated with emulsified silicone oil.

PURPOSE: To describe endothelial changes associated with emulsified silicone oil. METHODS: Report of a case. RESULTS: A 77-year-old man had multiple and diffuse clear vesicles on the endothelium of his left eye (LE). The cornea was clear and thin. He had undergone pars plana vitrectomy and intraocular silicone oil injection 5 years before presentation. Specular microscopy revealed numerous small bubbles of emulsified silicone oil and a mild degree of endothelial damage. CONCLUSION: Emulsified silicone oil can adhere to the endothelium and induce an apparent droplet-like endotheliopathy.

Aged↗
PubMed1999

Filtration procedures supplemented with mitomycin C in the management of childhood glaucoma.

AIMS: To evaluate the outcome of filtering procedures supplemented with mitomycin C in children with glaucoma. METHODS: All patients aged 17 or younger with glaucoma who underwent filtering surgery supplemented with mitomycin C at a tertiary care centre (n = 21) during a 5 year interval (1992 and 1996) were included. One eye for each patient was entered into the analysis. The postoperative intraocular pressure (IOP), use of antiglaucoma medications, clinical stability of glaucoma, complications, and visual acuity were retrospectively evaluated. Kaplan-Meier survival curves were used to estimate the probability of success. RESULTS: At the time of surgery mean age was 5.7 (SD 5.0) years. The most common diagnoses were trabeculodysgenesis (n = 6) and aphakic glaucoma (n = 8). Mean IOP before surgery was 35.7 (10.5) mm Hg. Average length of follow up was 18.6 (14.7) months. The probability of having IOP less than 21 mm Hg with no antiglaucoma medications and with clinically stable glaucoma 1 year after surgery was 76.9% in phakic eyes (n = 13) and 0% in aphakic eyes (n = 8). A phakic patient with Sturge-Weber's syndrome had choroidal effusion after surgery that resolved spontaneously. In the aphakic group one patient had retinal detachment and another developed an encapsulated bleb. Visual acuity deteriorated in one patient. CONCLUSION: A guarded filtration procedure with mitomycin C is relatively successful in phakic children with glaucoma, but unsuccessful in aphakic ones.

Adolescent↗
PubMed1999

Comparison between laser scanning tomography and computerised image analysis of the optic disc.

AIMS: To study the interchangeability of the measurements of the optic disc topography obtained by one computerised image analyser and one confocal laser tomographic scanner. METHODS: One eye of 28 patients with glaucoma or glaucoma suspects was studied. All cases had simultaneous stereoscopic disc photographs taken with the fundus camera Topcon TRC-SS and optic disc examination with the Heidelberg retina tomograph (HRT) during the same visit. The optic disc photographs were digitised and analysed with the Topcon ImageNet (TI) system. Three variables of the optic disc topography provided by the TI and the HRT were compared--cup volume (CV), rim area (RA), and cup area to disc area ratio (CA/DA). RESULTS: The mean values of CV and RA provided by the TI (0.52 (SD 0.32) mm3 and 1.58 (0.39) mm2, respectively) were greater (p < 0.01) than the mean values of CV and RA determined by the HRT (0.32 (0.25) mm3, and 1.33 (0.47) mm2, respectively). The mean value of CA/DA provided by the TI (0.42 (0.14)) and the HRT (0.42 (0.18)) was similar (p = 0.93). Correlation coefficients between measurements obtained by the two methods ranged from 0.53 to 0.73. CONCLUSION: There was a significant discrepancy in the measurements of rim area and cup volume of the optic disc obtained by a computerised image analyser and a laser scanning tomograph.

Adult↗
PubMed1999

Amniotic membrane transplantation for ocular surface reconstruction.

AIMS: To evaluate the efficacy of amniotic membrane transplantation (AMT) for ocular surface reconstruction. METHODS: 10 consecutive patients who underwent AMT were included. The indications were: group A, cases with persistent epithelial defect after corneal abscess (n = 1), radiation (n = 1), or chemical burn (n = 3); group B, cases with epithelial defect and severe stromal thinning and impending or recent perforation, due to chemical burn (two patients, three eyes) or corneal abscess (n = 2); group C, to promote corneal epithelium healing and prevent scarring after symblepharon surgery with extensive corneo-conjunctival adhesion (n = 1). Under sterile conditions amniotic membrane was prepared from a fresh placenta of a seronegative pregnant woman and stored at -70 degrees C. This technique involved the use of amniotic membrane to cover the entire cornea and perilimbal area in groups A and B, and the epithelial defect only in group C. RESULTS: The cornea healed satisfactorily in four of five patients in group A, but the epithelial defect recurred in one of these patients. After AMT three patients underwent limbal transplantation and one penetrating keratoplasty and cataract extraction. In group B amniotic membrane transplantation was not helpful, and all cases underwent an urgent tectonic corneal graft. Surgery successfully released the symblepharon, promoted epithelialisation and prevented adhesions in the case of group C. CONCLUSION: AMT was effective to promote corneal healing in patients with persistent epithelial defect, and appeared to be helpful after surgery to release corneo-conjunctival adhesion. Most cases required further surgery for visual and ocular surface rehabilitation. Amniotic membrane used as a patch was not effective to prevent tectonic corneal graft in cases with severe stromal thinning and impending or recent perforation.

Adult↗
PubMed1999

Allo-limbal transplantation in patients with limbal stem cell deficiency.

AIM: To report the outcome of a series of patients with stem cell deficiency who underwent allo-limbal transplantation and to describe a technique for this procedure. METHODS: Six consecutive patients underwent allo-limbal stem cell transplantation. The primary diagnosis included alkali burn (n = 2), trachoma (n = 1), chronic rosacea blepharitis and kerato-conjunctivitis (n = 1), aniridia (n = 1), and Stevens-Johnson syndrome (n = 1). The limbal rim consisted of peripheral cornea and perilimbal sclera. FK-506 was used postoperatively for immunosuppression. RESULTS: The length of follow up ranged from 3 to 24 months (mean follow up 11.8 (SD 9.3) months). The outcome was considered satisfactory in five of six cases. The corneal surface was completely epithelialised within 2 weeks, and there was a substantial improvement in vision and symptoms. One patient had recurrent epithelial defects related to eyelid abnormalities. No side effects associated with systemic immunosuppression were noted. CONCLUSION: Allo-limbal transplantation, with systemic immunosuppression with FK-506 is useful in reconstruction of the ocular surface with improvement in vision in patients with severe stem cell deficiency.

Adult↗
PubMed1999

Oral prednisone in guarded filtration procedures supplemented with antimetabolites.

BACKGROUND AND OBJECTIVE: To evaluate whether a three-day course of oral prednisone perioperatively improves the surgical outcome of guarded filtering procedures supplemented with antifibrosis agents. DESIGN, MATERIALS AND METHODS: A prospective, randomized, double-masked, placebo-controlled, clinical trial was designed. Adult patients with non-inflammatory glaucoma undergoing a guarded filtration procedure supplemented with antimetabolite were enrolled. Patients received a three-day course of prednisone (50 mg BID) or placebo perioperatively. The main outcome measures were intraocular pressure (IOP) and number of antiglaucoma medications. Surgical success was defined before data collection according to two different criteria: "success-I": IOP level < or = 15 mmHg with no more than one anti-glaucoma medication, and "success-II": IOP reduction of at least 20% of baseline level with no more than one antiglaucoma medication. RESULTS: Thirty-five subjects were enrolled. Seventeen patients were treated with prednisone and eighteen with placebo. Mean follow-up was 9.2 months +/-6.2 months. The probability of success-I at 9 months was 63.0% in the study group and 65.6% in the control groups (p>0.05). The probability of success-II at 9 months was 60.2% in the study group and 55.0% in the control groups, (p>0.05). The difference in frequency of postoperative complications between groups was not statistically significant. The most common complication was choroidal detachment (n=2) in the prednisone-treated group and bleb leak (n=2) in the control group. CONCLUSION: The perioperative use of oral prednisone did not alter the surgical outcome of filtering procedures associated with antifibrosis agents in this population of glaucoma patients.

Administration, Oral↗
PubMed1999

Corneal allograft rejection: risk factors, diagnosis, prevention, and treatment.

Recent advances in corneal graft technology, including donor tissue retrieval, storage and surgical techniques, have greatly improved the clinical outcome of corneal grafts. Despite these advances, immune mediated corneal graft rejection remains the single most important cause of corneal graft failure. Several host factors have been identified as conferring a "high risk" status to the host. These include: more than two quadrant vascularisation, with associated lymphatics, which augment the afferent and efferent arc of the immune response; herpes simplex keratitis; uveitis; silicone oil keratopathy; previous failed (rejected) grafts; "hot eyes"; young recipient age; and multiple surgical procedures at the time of grafting. Large grafts, by virtue of being closer to the host limbus, with its complement of vessels and antigen-presenting Langerhans cells, also are more susceptible to rejection. The diagnosis of graft rejection is entirely clinical and in its early stages the clinical signs could be subtle. Graft rejection is largely mediated by the major histocompatibility antigens, minor antigens and perhaps blood group ABO antigens and some cornea-specific antigens. Just as rejection is mediated by active immune mediated events, the lack of rejection (tolerance) is also sustained by active immune regulatory mechanisms. The anterior chamber associated immune deviation (ACAID) and probably, conjunctiva associated lymphoid tissue (CALT) induced mucosal tolerance, besides others, play an important role. Although graft rejection can lead to graft failure, most rejections can be readily controlled if appropriate management is commenced at the proper time. Topical steroids are the mainstay of graft rejection management. In the high-risk situations however, systemic steroids, and other immunosuppressive drugs such as cyclosporin and tacrolimus (FK506) are of proven benefit, both for treatment and prevention of rejection.

Corneal Transplantation↗