PubMed Health⌕ Search

Biomedical subjects

P F Lopez

Publications and source records attributed to P F Lopez.

At least 37 records · Page 2Linked to original sources
PubMed1994

Encircling panretinal laser photocoagulation may prevent macular detachment after vitrectomy for proliferative diabetic retinopathy.

Macular detachment due to peripheral retinal tears that occur after pars plana vitrectomy for proliferative diabetic retinopathy can result in severe visual loss despite successful retinal reattachment. The authors reviewed the records of three patients who developed peripheral sclerotomy-related rhegmatogenous retinal detachments one to six months after vitrectomy for proliferative diabetic retinopathy, despite the absence of detectable sclerotomy-related retinal tears by indirect ophthalmoscopy and scleral depression at the conclusion of surgery. All three patients had received standard panretinal laser photocoagulation in a complete encircling pattern either prior to or during the initial vitrectomy. Clinically or echographically, each patient was seen to have a partial or complete annual peripheral sclerotomy-related rhegmatogenous retinal detachment delimited to the equator. In each of these three cases, posterior extension of the peripheral retinal detachment into the macular area was prevented by the most anterior row of the photocoagulation scars. Standard panretinal laser photocoagulation applied in a complete encircling pattern may be useful in the prophylaxis of macular detachment from sclerotomy-related retinal tears that occur after vitrectomy for proliferative diabetic retinopathy.

Aged↗
PubMed1994

Echographic findings in hemorrhagic disciform lesions.

PURPOSE: To examine the potential role of ocular echography in the evaluation of hemorrhagic disciform disease. METHODS: Using standardized ocular echography, the authors examined 85 eyes of 85 patients with hemorrhagic disciform lesions. RESULTS: Hemorrhagic disciform lesions are located in the subretinal pigment epithelial space and appear echographically as solid chorioretinal elevations characterized by a bumpy, lobulated surface with indistinct peripheral margins, irregular internal structure, and medium to high internal reflectivity. These lesions could be reliably differentiated from associated subretinal or suprachoroidal hemorrhage by ocular echography when the maximal height of the lesion was 1 mm or greater. CONCLUSIONS: Hemorrhagic disciform disease is usually complex with distinct components that may not be discernible on biomicroscopic or angiographic examination, in part because of overlying subretinal hemorrhage. Ocular echography provides a readily available clinical tool to define the components of hemorrhagic disciform disease more precisely. Improved characterization of hemorrhagic disciform lesions may improve understanding of the natural history and response to therapy of hemorrhagic age-related macular degeneration.

Aged↗
PubMed1994

En bloc capsulectomy in the diagnosis and treatment of refractory, chronic, recurrent pseudophakic endophthalmitis.

Anterior chamber and vitreous aspiration may fail to isolate a microorganism in chronic pseudophakic endophthalmitis. In some eyes, obtaining a portion of the central posterior lens capsule may assist in determining the infectious etiology of the endophthalmitis. We describe a technique by which the entire lens capsule and its internal contents are removed and cultured. This surgical method facilitated the isolation and eradication of the causative pathogen in a patient with chronic recurrent pseudophakic endophthalmitis that was diagnostically and therapeutically refractory to previous vitrectomy, posterior capsulectomy, and intravitreal antibiotic injection.

Aged↗
PubMed1993

Diode-laser photocoagulation for zone 1 threshold retinopathy of prematurity.

We used the diode-laser indirect ophthalmoscope in the treatment of 17 (30 eyes) infants with zone 1 (a circle centered on the optic disk with a radius of twice the distance from the disk to the fovea) threshold retinopathy of prematurity (at least five continuous or eight cumulative 30-degree sectors [clock hours] of ridge with extraretinal fibrovascular proliferation in the presence of plus disease). Mean follow-up was 31.2 weeks. Two eyes (6.7%) required retreatment of missed areas that had persistent plus disease (enlarged posterior veins and tortuous arterioles). A favorable outcome was attained in 25 eyes (83.3%). Five eyes (16.7%) developed retinal detachments, three of which remained stable at Stage 4A (extrafoveal retinal detachment) and two of which ultimately progressed to Stage 5 (total retinal detachment). Both eyes that went on to Stage 5 had severe posterior pole hemorrhages at the time of treatment. Two eyes that developed retinal detachments (one, stage 4A and one, stage 5) had rhegmatogenous components. Among 14 infants followed up for more than three months, four developed nystagmus, and six developed strabismus. In contrast to cryoablation, diode-laser photoablation of the peripheral retina was found to be an effective treatment for threshold retinopathy of prematurity located in zone 1. Portability and ease of use of the laser system, precision of treatment, and minimal postprocedural adnexal inflammation are further advantages of this therapeutic modality.

Female↗
PubMed1993

Pneumococcal endophthalmitis associated with nasolacrimal obstruction.

Pneumococcal endophthalmitis can be a devastating postoperative infection after cataract extraction or penetrating keratoplasty. Streptococcus pneumoniae was isolated as the causative agent in three of the 124 patients (2%) who were treated for endophthalmitis at our institution between 1984 and 1990. Two of the three patients lost light perception in the affected eye. All three patients had previously unrecognized or untreated chronic nasolacrimal obstruction of varying causes. We studied the role of pneumococcal lacrimal conjunctivitis in the pathogenesis of the postoperative pneumococcal endophthalmitis in these patients.

Aged↗
PubMed1993

Ultrastructural features of surgically excised subretinal neovascular membranes in the ocular histoplasmosis syndrome.

We evaluated the ultrastructural features of seven surgically excised submacular neovascular membranes from seven patients with the ocular histoplasmosis syndrome. Excised neovascular membranes were composed of fibrovascular tissue interposed between Bruch's membrane and the retinal pigment epithelium. Cellular components present in the membranes included, in decreasing order of frequency, retinal pigment epithelium, vascular endothelium, photoreceptor cells, macrophages, erythrocytes, ghost erythrocytes, fibrocytes, myofibroblasts, glial cells, smooth-muscle cells, and lymphocytes. Extracellular constituents of the neovascular membranes included 20 to 25-nm collagen fibrils, fibrin, 10-nm collagen fibrils, and fragments of Bruch's membrane and choroid. Our findings are consistent with the concept that subretinal neovascular membranes in the ocular histoplasmosis syndrome represent a nonspecific healing response to a local stimulus or injury.

Adolescent↗
PubMed1993

Well-defined subfoveal choroidal neovascular membranes in age-related macular degeneration.

PURPOSE: The purpose of this study is to correlate the clinical, angiographic and ultrastructural features of well-defined subfoveal neovascular membranes. METHODS: Fundus photographs and fluorescein angiograms of five well-defined subfoveal neovascular membranes associated with age-related macular degeneration and exudative retinal detachment were obtained. The subfoveal membranes were surgically excised via the pars plana. The center and peripheral portions of each membrane were evaluated by transmission electron microscopy for cellular and extracellular constituents. RESULTS: Each subretinal neovascular membrane was composed of two distinct regions demonstrated by fluorescein angiography. The first component, the core, contained a brighter central area of hyperfluorescent leakage surrounded by a partial or complete cuff of elevated blocked choroidal fluorescence. Results of ultrastructural examination showed that the core was composed of a fibrovascular membrane characterized by endothelium-lined vascular channels with associated retinal pigment epithelium. The second region of the membrane, the rim, is previously unreported and is described in detail. It appeared as a minimally elevated, smooth, subretinal annular rim of hyperfluorescent staining that surrounded the core and was composed of fibrin, photoreceptor outer segments, and macrophages. CONCLUSIONS: Well-defined subfoveal neovascular membranes can be appreciated with fluorescein angiography and are composed of a central core of subfoveal choroidal neovascularization surrounded by a peripheral rim composed of fibrin, photoreceptor outer segments, and macrophages.

Aged↗
PubMed1993

Surgical excision of subfoveal choroidal neovascular membranes.

The possibility for visual improvement after the treatment of subfoveal choroidal neovascular membranes with laser photocoagulation is poor. The surgical excision of these membranes in age-related macular degeneration, the presumed ocular histoplasmosis syndrome, idiopathic neovascularization, and myopia is the focus of current study. This review covers the rationale for considering a surgical approach, the techniques currently used to perform these procedures, and the clinical pathological correlation of the surgically excised specimens. Initial results of this surgery warrant a national randomized clinical trial of its efficacy.

Choroid↗
PubMed1992

Vogt-Koyanagi-Harada syndrome in patients with Cherokee Indian ancestry.

Eight patients with Vogt-Koyanagi-Harada syndrome who have Cherokee Indian ancestry ranged from 17 to 49 years of age. Five of the patients were black, three were white. Visual acuity at the time of initial examination ranged from 20/20 to counting fingers. Clinical findings included granulomatous iridocyclitis in six patients, vitreitis in seven patients, disk edema in five patients, exudative retinal detachment in six patients, and multifocal choroidal lesions in all eight patients. All of the patients were treated with systemic corticosteroids, and they recovered visual acuity of 20/40 or better. The seven patients assayed had the HLA-DRw52 haplotype, including five who were homozygous for this allele. This finding may add to the increasing evidence that a class II HLA antigen at a D-related locus may predispose carriers to the development of Vogt-Koyanagi-Harada syndrome.

Adolescent↗
PubMed1992

Immunohistochemical and histochemical properties of surgically excised subretinal neovascular membranes in age-related macular degeneration.

The immunohistochemical and histochemical properties of 16 surgically excised subretinal neovascular membranes from 16 patients with age-related macular degeneration were studied. Primary antisera to c-retinaldehyde-binding protein; leukocyte common antigen; factor VIII-related antigen; S-100 protein; glial fibrillary acid protein; muscle-specific actin; neuron-specific enolase; collagen types I, II, III, IV, and V; laminin; and fibronectin were used for immunohistochemical characterization of the membranes. Histochemical staining for lipid and mucopolysaccharide was performed. The results of the staining in conjunction with histologic examination showed the cellular components of the membranes to be composed of retinal pigment epithelium, inflammatory cells, vascular endothelium, glial cells, myofibroblasts, photoreceptor cells, and fibrocytes. The extracellular matrix of the membranes contained collagen types I, III, IV, and V; fibronectin; laminin; mucopolysaccharide; and lipid. These findings are consistent with the concept that subretinal neovascular membranes in age-related macular degeneration are composed of localized intra-Bruch's membrane granulation tissue proliferation associated with diffuse drusen.

Aged↗
PubMed1992

Pathogenetic mechanisms in anterior proliferative vitreoretinopathy.

A clinicopathologic study of ten consecutive patients (ten eyes) undergoing surgery for rhegmatogenous retinal detachment with anterior proliferative vitreoretinopathy and a subsequent histopathologic, immunohistochemical, and ultrastructural study of ten enucleated eyes with anterior proliferative vitreoretinopathy were performed in order to elucidate relevant pathogenetic mechanisms. Our findings suggest that the pathogenetic evolution of anterior proliferative vitreoretinopathy occurs in three consecutive stages: (1) traction on the ciliary body and peripheral retina induced by fibrocellular contraction of the vitreous base; (2) incorporation of tractionally denuded components of the ciliary body and peripheral retina into the fibrocellular membranes overlying the vitreous base; and (3) proliferation of the incorporated components and fibrovascular ingrowth from the uvea, the retina, or both, into the fibrocellular membranes. Tractional disruption of the epithelium of the ciliary body pars plicata and breakdown of the ciliary blood-aqueous barrier are the principal pathogenetic mechanisms of chronic intractable hypotony and the post-vitrectomy fibrin syndrome in anterior proliferative vitreoretinopathy.

Adult↗
PubMed1992

Examination of macular vitreoretinal interface disorders with monochromatic photography.

Monochromatic light accentuates details of different retinal layers because of its variable absorption and reflectance by structures both within and above these layers. Monochromatic photography was used to examine macular vitreoretinal interface abnormalities in 19 patients. Short wavelength photographs (490 nm) provided the best detail of inner retinal abnormalities, including epiretinal membranes, vitreoretinal traction, and the internal surface of confluent macular edema (pseudocyst). Although 540-nm red-free photography provided acceptable photographs, it did not provide optimal detail of inner or deep retinal abnormalities. Longer wavelengths, 585 and 610 nm, best disclosed the extent of deep retinal abnormalities, including the extent of confluent macular edema (pseudocysts) and retinal detachment that surrounded macular holes. The addition of short- and long-wave-length photography to traditional red-free photography may provide better localization, understanding, and documentation of the three-dimensional relationships in macular vitreoretinal interface disorders.

Eye Diseases↗
PubMed1992

Surgical excision of subfoveal neovascular membranes in age-related macular degeneration.

We studied the results of surgical excision of ten consecutive subfoveal choroidal neovascular membranes in ten patients with age-related macular degeneration. The criteria for surgical eligibility included the following: (1) a clearly identifiable subfoveal membrane occupying the entire foveal avascular zone, (2) a visual acuity of 20/200 or worse, (3) minimal subretinal hemorrhage, and (4) an associated exudative macular detachment. Six of the ten patients showed visual improvement at one-month and three-month follow-up visits and seven showed visual improvement by the six-month examination. All ten maculae remained attached without recurrence of subfoveal neovascular membranes throughout the follow-up period. These results suggested that surgical excision is a viable alternative to laser photocoagulation in patients with subfoveal neovascularization in age-related macular degeneration.

Aged↗
PubMed1992

Management of threshold retinopathy of prematurity.

The Cryotherapy for Retinopathy of Prematurity Study demonstrated the benefit of intervention for threshold disease. The authors reviewed their experience with cryotherapy, investigating the questions of treatment for bilateral disease. Between 1985 and 1990, 71 eyes from 41 infants with threshold retinopathy of prematurity were treated. Of the 65 eyes with a minimum of 3 months follow-up, only 7 eyes (11%) progressed to stage 4, although an additional 8 eyes (13%) developed a posterior retinal fold. Although the overall results are comparable to those repeated by the Cryotherapy for Retinopathy of Prematurity Study, the authors recommend treating both eyes if they reach threshold, and treating the two eyes at the same sitting.

Cryosurgery↗