Biomedical subjects

Enrique Garcia-Valenzuela

Publications and source records attributed to Enrique Garcia-Valenzuela.

9 recordsLinked to original sources

PubMed2005

Multilayered retinal microglial response to optic nerve transection in rats.

PURPOSE: Microglia normally exist in several layers across the retinal thickness. When retinal ganglion cells undergo apoptosis after lesion to their axons, microglial cells proliferate and promptly clear the debris. We have previously reported on the phagocytic response following optic nerve axotomy. Here, we present how microglial cells of deeper retinal layers are affected by transection of the optic nerve. METHODS: Normal and reactive microglia in the retina of adult rats whose optic nerves had been lesioned were labeled by using antibodies OX42 and ED1. Analysis of the time course (between 1 and 180 days post-axotomy) of appearance and distribution of microglial cells in the retinal layers was performed. RESULTS: In normal retinas, microglia were found in the ganglion cell layer (GCL), the superficial inner nuclear layer (INL) and the outer plexiform layer (OPL). Increases in numbers of microglia occurred maximally in the GCL at day 12 post-axotomy. Increases were also detected in the superficial INL. The proliferation of these phagocytic cells led to their highest numbers in the more central eccentricities in the two most superficial layers. Microglia in the OPL remained undisturbed. Microglial normal histology is restored over a period of 6 months as dying ganglion cells disappear. CONCLUSIONS: Histological characteristics of normal rat retinal microglia are uniform across different retinal eccentricities for each of the three laminae where they exist. Retinal microglia of various layers respond to optic nerve damage. Their increase in numbers and morphological transformation follow retinal ganglion cell death. Their morphology, density, and layered distribution slowly return to normal, confirming that retinal ganglion cells, or their densities, do not play any role in dictating microglial distribution within the different retinal layers.

Animals↗

PubMed2005

Intracorneal injection of amphothericin B for recurrent fungal keratitis and endophthalmitis.

Penetrating keratoplasty carries an infectious risk. Its requirement for topical corticosteroid therapy facilitates fungal growth with resulting keratitis. Although progression of fungal keratitis to intraocular infection is uncommon, endophthalmitis resulting from keratitis usually has a poor visual prognosis. Fungal infection under these circumstances remains a diagnostic and therapeutic challenge. We report a complicated case of recurrent fungal keratitis with endophthalmitis following a contaminated penetrating keratoplasty that ultimately was controlled with a new treatment modality. Intrastromal corneal injections combined with intravitreal injection of amphotericin B led to the eradication of the corneal fungal plaques and the intraocular infection. Intrastromal corneal injections of amphotericin B may offer a less invasive, in-office alternative to repeat penetrating keratoplasty.

Aged, 80 and over↗

PubMed2005

High myopia associated with retinopathy of prematurity is primarily lenticular.

PURPOSE: To determine which of the eye's refractive components are responsible for the high myopia in retinopathy of prematurity (ROP), as compared with highly myopic eyes in full-term patients. METHODS: The study included 53 highly myopic eyes in 34 patients with a history of ROP, and 66 highly myopic eyes in 37 full-term patients. Measurements included refraction, keratometry, and A-scan values for axial length, lens thickness, lens position, anterior chamber depth, anterior segment depth, and lens power calculations. Comparisons were also made with published age-matched, full-term normal controls. RESULTS: Refractions ranged from a spherical-equivalent of -5.0 to -20.75, and from -5.0 to -22.0 diopters in ROP and full-term eyes, respectively. For ROP eyes, increasing myopia was most associated with lens thickness and lens power ( P < 0.001), with lesser contributions from corneal steepness, axial length, and a more forward position of the lens's center. For the eyes with myopia in full-term patients, increasing myopia was highly associated with axial length ( P < 0.001), with smaller contributions from increased lens thickness and lens power. ROP eyes had a lens-thickness/anterior-chamber-depth ratio almost 50% higher than FT and normative eyes. Anterior segment depth was remarkably similar in all eyes studied. CONCLUSIONS: High myopia associated with ROP appears pathophysiologically distinct from high myopia in full-term patients. The increased lens thickness seen in ROP eyes was accompanied by shallower anterior chamber depth and maintenance of the anterior segment depth, similar to the normal neonatal eye, suggesting a mechanism of altered anterior segment development in ROP leading to high myopia.

Adolescent↗

PubMed2005

Redefining the limit of the outer retina in optical coherence tomography scans.

OBJECTIVE: A highly reflective layer seen in retinal optical coherence tomography (OCT) has been believed to correspond to the choriocapillaris (CHC) and retinal pigment epithelium (RPE). On gray-scale scans of OCT-2000, and on Stratus OCT, this layer by the outer retinal limit can be resolved into 2 distinct laminae. We analyzed these 2 laminae in normal and abnormal maculae to infer their anatomic correlate. DESIGN: Retrospective study. METHODS: Analysis of macular OCT scans was performed in 44 patients using OCT-2000, and in 39 patients using Stratus OCT. Thirty of these patients had no ocular disease, and their OCT was normal. The other 53 patients had several macular diseases of different etiologies. Both color and gray-scale images were analyzed. RESULTS: Macular OCT scans showed a double laminae at the level where the retina interfaces the RPE in normal subjects using both OCT-2000 and Stratus OCT. In 2-dimensional scans, this laminar structure appears as a double line. It is best distinguished on the Stratus OCT and gray-scale images of OCT-2000. This double line consisted of a thin inner line and a thicker outer line. Similar analysis in patients with macular pathology showed a discernible double line at the retina/RPE interface in at least part of the scan. However, in patients with macular hole, the area corresponding to the absent retina showed only a single line. The inner line component appeared to follow the contour of the retina. This phenomenon was also seen in eyes with neurosensory detachment secondary to central serous chorioretinopathy and other etiologies. In contrast, in macular pathologies where the outer retina did not lose contiguity with the RPE, such as in lamellar macular hole and in cystoid macular edema, the double line persisted. Software for retinal thickness measurements regularly place the outer limit of the retina at the internal aspect of the inner line, probably underestimating the retinal thickness by about 24 to 34 mum. CONCLUSIONS: A double laminar structure at the outer retina/RPE/CHC interface can be consistently distinguished on commercially available OCT of normal eyes. In eyes with macular pathology, OCT analysis of the inner lamina leads us to conclude it is most likely part of the neurosensory retina and not part of the RPE/CHC complex as previously thought.

Adult↗

PubMed2004

Hypopyon uveitis and relapsing polychondritis: a report of 2 patients and review of autoimmune hypopyon uveitis.

OBJECTIVE: To report hypopyon uveitis as an ophthalmic finding associated with relapsing polychondritis. DESIGN: Interventional case reports. PARTICIPANTS: Two patients with hypopyon uveitis as a manifestation of relapsing polychondritis. METHODS: Complete ocular and systemic examinations as well as chart reviews were performed for 2 patients with hypopyon uveitis as a manifestation of relapsing polychondritis at presentation. MAIN OUTCOME MEASUREMENTS: Clinical observation and response to treatment in 2 patients with hypopyon uveitis secondary to relapsing polychondritis. RESULTS: A 70-year-old white male had unilateral hypopyon uveitis accompanied by a migratory polyarthralgia at presentation. Fifteen months later, he sought treatment for chondritis of the right auricle and was diagnosed with relapsing polychondritis. A 42-year-old white female with known relapsing polychondritis had bilateral hypopyon uveitis at presentation during a systemic relapse. Both patients had resolution of the hypopyon with topical and systemic steroids. CONCLUSIONS: Relapsing polychondritis should be considered in the differential diagnosis of sterile hypopyon uveitis. Steroids and systemic immunosuppression can be used to treat the uveitis.

Adult↗

PubMed2004

Risk factors for retention of subretinal perfluorocarbon liquid in vitreoretinal surgery.

PURPOSE: To analyze factors that may lead to inadvertent subretinal retention of perfluorocarbon liquid (PFCL) after vitreoretinal surgery and compare surgical outcomes and complications associated with these events. DESIGN: Consecutive retrospective study. METHODS: The authors retrospectively reviewed the charts of 72 vitreoretinal surgeries using intraoperative PFCL and its removal through fluid-air exchange and subsequent tamponade. Indications for surgery included trauma, retinal detachment, giant retinal tear, and submacular hemorrhage. Most interventions studied had significant amounts of proliferative vitreoretinopathy and were required after failed or complicated previous vitreoretinal surgery. MAIN OUTCOME MEASURES: Analysis was focused on the occurrence of subretinal retention of PFCL during different surgical procedures and techniques, indications, anatomic and visual results, and complications. RESULTS: At the last follow-up, the retina was completely attached in 97% of eyes treated with PFCL after 1 or 2 vitrectomies. Subretinal PFCL was found in 8 (11.1%) eyes. There was no statistical difference in the retention rate for perfluorodecalin and perfluoro-n-octane. The factor most significantly associated with subretinal retention of PFCL was the presence and large size of a peripheral retinotomy. All cases of subretinal PFCL had a retinotomy of 120 degrees or larger. The average retinotomy size in these cases was 259 degrees . Subretinal PFCL was found in 40% of eyes with a 360 degrees retinotomy. Small and medium-sized retinal breaks were not associated with PFCL retention. Another surgical procedure that correlated significantly with subretinal PFCL was lack of saline rinse during fluid-air exchange. Only 1 of the 23 eyes that were rinsed had subretinal PFCL, although many had large retinotomies. CONCLUSION: Subretinal PFCL retention is most likely to occur in eyes with large peripheral retinotomies, especially if 360 degrees . Saline rinse seems to be useful in the prevention of subretinal PFCL. The presence of subretinal PFCL does not seem to affect visual and anatomic success when located outside the macula, at least during an intermediate period of follow-up.

Adolescent↗

PubMed2003

Reduced need for corneal epithelial debridement during vitreo-retinal surgery using two different viscous surface lubricants.

PURPOSE: Corneal clarity is frequently reduced during vitrectomy and scleral buckling surgery secondary to epithelial edema, requiring epithelial debridement to improve visibility. The presence of toxic preservatives in the corneal lubricant solutions is hypothesized to be a contributing factor to epithelial edema during vitreo-retinal surgery. DESIGN: Interventional study. METHODS: We compared prospectively the corneal clarity and epithelial debridement frequency in 71 patients within a single institution in whom either Goniosol (2.5% methylcellulose, boric acid, edetate disodium, sodium borate, potassium chloride, water, and 0.01% benzalkonium chloride) or GenTeal gel (0.3% hydoxypropyl-methylcellulose, carbopol 980, phosphonic acid, sorbitol, water, and 0.028% sodium perborate) was used as a corneal lubricant during the course of vitrectomy surgery using sutured contact lenses. Corneal clarity was subjectively graded in a scale of I to IV during surgery. Statistical analysis was made between these two groups for parametric and categorical data. RESULTS: All eyes started with a corneal clarity grade of I (best possible). Corneal clarity decreased significantly faster in eyes where Goniosol was used to a median grade of III at 1 hour of surgical time. In eyes where GenTeal gel was used, corneal clarity decreased much slower, to a median grade of I at 1 hour of surgical time. The difference in frequency of epithelial debridement was also statistically significant: 54% and 14% for Goniosol and GenTeal eyes, respectively. Other factors that may cause corneal epithelial edema and affect corneal clarity were not statistically different between the Goniosol and the GenTeal groups, including median operative time, estimated intraocular pressure, pre- and intraoperative topical solutions and medications, and number of prior ocular procedures. CONCLUSIONS: The use of GenTeal gel as a corneal lubricant maintains corneal clarity longer than Goniosol during the course of vitrectomy surgery using a contact lens viewing system, limiting the need for epithelial debridement.

Adolescent↗

PubMed2002

Vitreous hemorrhage as the initial presentation of postoperative endophthalmitis.

PURPOSE: To describe a patient with postoperative endophthalmitis whose only abnormal finding at presentation was a vitreous hemorrhage. DESIGN: Interventional case report. METHODS: A 68-year-old diabetic woman underwent cataract extraction with intraocular lens implantation in the left eye. Three days after surgery, she had painless loss of vision, minimal anterior chamber inflammation, and dense vitreous hemorrhage in the left eye. RESULTS: On the fourth postoperative day, significant anterior chamber inflammation developed with fibrin and a hypopyon. During vitrectomy with intravitreal antibiotic injection, an area of retinitis surrounding an eroded retinal blood vessel was found. Cultures of undiluted vitreous fluid grew coagulase-negative Staphylococcus organisms. The endophthalmitis resolved and 20 months later, her best-corrected visual acuity had improved to 20/40. CONCLUSION: Postoperative endophthalmitis may present as a vitreous hemorrhage, secondary to retinitis and erosion of a retinal blood vessel.

Aged↗

PubMed2002

Bilateral panuveitis in a child with hypohidrotic ectodermal dysplasia.

PURPOSE: To report a case of bilateral panuveitis in a patient with hypohidrotic ectodermal dysplasia. DESIGN: Interventional case report. METHODS: A 6-year-old African-American boy with hypohidrotic ectodermal dysplasia presented with pain, photophobia, and decreased vision in both eyes. RESULTS: Findings included severe bilateral panuveitis with optic disk edema, macular epiretinal membrane, peripheral retinal vasculitis, and retinitis. All other known causes of panuveitis were explored and ruled out. CONCLUSIONS: The abnormal development of tissues of ectodermal origin evident in hypohidrotic ectodermal dysplasia may include a predisposition to panuveitis.

Child↗