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Biomedical subjects

M A Lemp

Publications and source records attributed to M A Lemp.

At least 37 records · Page 2Linked to original sources
PubMed1991

Tight lens syndrome associated with a 24-hour disposable collagen lens: a case report.

Tight lens syndrome occurred 8 hours after a 24-hour Bio-Cor bandage collagen lens (Bausch & Lomb, Inc.) was placed on the eye of a 19 year old female patient with a history of Stevens-Johnson syndrome and recurrent corneal abrasions. Because collagen bandage contact lenses share some physical and fitting properties with hydrophilic lenses, they should be used with caution in patients at high risk for a tight lens.

Adult↗
PubMed1990

Estrogen and progesterone receptors and human conjunctiva.

Freshly frozen conjunctival tissue from premenopausal and postmenopausal women and male subjects were processed for estrogen and progesterone receptors by using monoclonal antibodies and a peroxidase-antiperoxidase technique. No immunocytochemical staining was localized in the nuclei of the cells treated with the monoclonal antibodies to human estrogen receptor or human progesterone receptor in any of the conjunctival specimens, in contrast to the strongly positive staining in breast adenocarcinoma controls. Immunocytochemical staining disclosed no evidence for estrogen or progesterone receptors on cells of the ocular surface.

Adenocarcinoma↗
PubMed1990

[Tear film diagnosis in contact lens wearers].

Contact lenses have an intimate relationship with the precorneal tear film and it is important to attempt to prognosticate the likelihood of successful contact lens wear by evaluating, both quantitative and qualitative aspects of the precorneal tear film. Aspects of history diagnostic methods and general aspects which are necessary to notice prior to contact lens fitting are described in this review.

Contact Lenses↗
PubMed1990

Is the dry eye contact lens wearer at risk? Yes.

Numerous studies have demonstrated that patients with dry eyes have a compromised ocular surface. Furthermore, these patients suffer deficiencies of various surface defense mechanisms, such as tear volume, tear components (lysozyme, lactoferrin, and beta-lysin), the mucin network, cellular exfoliation, and subsurface immune secretions. When such individuals wear contact lenses (CLs), a special set of circumstances arises that increases the risk of ocular infection. The risk is greatest if the lenses are soft and, therefore, provide for little tear exchange beneath their surface. Under such circumstances, limited tear flow allows for a greater buildup of lens deposits and metabolic wastes, while permitting increased tear evaporation from the lens surface. The pathogenesis of infection is attributed to various mechanisms, including decreased tear flow beneath the lens, decreased tear components, stagnation of the mucin network, changes in surface cell exfoliation, and putative changes in the subsurface immune secretory system. Dry eye patients who wear soft CLs also run a greater risk of bacterial conjunctivitis, blepharitis, and sterile corneal infiltrates.

Contact Lenses↗
PubMed1990

The effect of relaxing incisions with multiple compression sutures on post-keratoplasty astigmatism.

We describe a surgical technique for correction of astigmatism following penetrating keratoplasty performed after all keratoplasty sutures have been removed. Two relaxing incisions of 3 clock hours, at 3/4 depth, 0.5 mm inside the keratoplasty wound are used in combination with two sets of three compression sutures placed 90 degrees from the incisions. Selective removal of the compression sutures allows for a graded reduction in overcorrection. With this technique, a mean preoperative astigmatism in 10 patients of 14.25 diopters was reduced to 6.33 D 3 months postoperatively (P less than .002). There were no intraoperative or postoperative complications such as inadvertent perforation, wound dehiscence, or graft rejection.

Adult↗
PubMed1989

Corneal epithelial cell movement in humans.

Evidence is presented which supports the centripetal movement of epithelial cells in the normal corneal epithelium. This movement is not, however, uniform and is influenced by various factors including corneal topography, surface disease states and lid shearing forces. We have studied epithelial morphology with corneal specular microscopy and have demonstrated altered morphology in keratoconjunctivitis sicca, neurotrophic keratitis, and contact lens wearing. Following penetrating keratoplasty, we found a vortex keratopathy in 70 per cent of patients up to two years after surgery. We also found pallisading of epithelial cells around sutures which indicated centripetal movement of epithelial cells around islands of stability created by obstructions. The eyelid also alters epithelial migration and turnover by increasing exfoliation from shearing forces. We advance a new hypothesis that the driving force in the central epithelial cell movement is the preferential loss of surface cells by exfoliation from the central apex secondary to the shearing forces of the upper lid.

Cell Movement↗
PubMed1989

Surface cell morphology of the anesthetic human cornea: a color specular microscopic study.

The technique of color specular microscopy has been utilized to study the surface cell morphology of the human cornea in 6 subjects with profound corneal anesthesia from diverse causes. In an analysis of cell area, perimeter, and shape, anesthetic corneas showed a statistically significant increase in cell size and perimeter. In addition, there was a loss of cellular outlines and overall increase in rose bengal staining of cells. We believe that these cellular microscopic changes reflect profound changes in epithelial cell turnover related to a decrease in neurohumoral transmitters known to be necessary for maintenance of normal corneal morphology and function.

Adult↗
PubMed1989

The surface of the corneal graft: in vivo color specular microscopic study in the human.

An in vivo microscopic study of the cellular morphology of the corneal graft surface, employing CSM, has been presented. The following epithelial cellular abnormalities have been noted on the graft surface: a high prevalence (70%) of central vortex keratopathy in the postoperative graft; a redirection of cells in a palisading pattern around sutures; a piling up of cells at the wound junction, with redirection parallel to the wound; cellular evidence of filaments and coarse mucus plaques near the suture line. Vortex keratopathy was not seen in grafts after sutures had been removed, and palisading of cells around sutures disappeared after suture removal. Central epithelial cell morphology in grafts 2 years or more after surgery resembled that of normal patients. A discussion of possible causative factors in the induction of epithelial abnormalities included sutures, corneal denervation, topographical changes, lid pressure, and tension effects on epithelial mitosis. Based on the observations of this CSM study, and based on other laboratory and clinical reports, a new hypothesis concerning epithelial cell movement in the cornea has been presented. It is proposed that there is a differential sliding of epithelium from the periphery to the center, and that epithelium is drawn centripetally by preferential loss of surface cells at the corneal center. Shearing forces of the upper lid cause maximal surface cell loss at the corneal center; shearing forces of the lid are lesser inferiorly and at the limbus. In areas of less lid force, as with depressions near graft sutures, areas of epithelial cell stability are created. Vortex patterns represent an exaggeration of normal cellular pathways of movement, occurring when differential sliding of cells is pronounced, as in corneal grafts.

Corneal Diseases↗
PubMed1988

Toxic endothelial degeneration in ocular surface disease treated with topical medications containing benzalkonium chloride.

We examined a 56-year-old man with keratoconjunctivitis sicca and marked ocular surface disease in whom the prolonged frequent use of topical medications containing the preservative benzalkonium chloride was associated with corneal endothelial damage requiring corneal transplantation in one eye. The histopathologic findings on examination of the excised button were consistent with toxic endothelial disease. Postoperatively, the patient's symptoms continued until the preservative-containing medications were substituted with nonpreserved saline eyedrops.

Benzalkonium Compounds↗
PubMed1988

Return of human corneal sensitivity after penetrating keratoplasty.

To evaluate the reinnervation of corneal grafts, we studied 91 eyes of 79 patients for the return of sensitivity one month to ten years following penetrating keratoplasty for various corneal disorders including keratoconus, Fuchs' dystrophy, herpes simplex keratitis, aphakic and pseudophakic bullous keratopathy, glaucoma, trauma, and interstitial keratitis. Using the Cochet-Bonnet esthesiometer, a sensation was recorded in the center of the graft no earlier than 18 months. We found a progressive return of sensitivity from the periphery toward the center of the graft. Regression analysis indicated a rate of return of sensitivity that averaged 0.029 mm/mo for each diagnostic category except herpes simplex keratitis. The slope of the return of sensitivity in the group with herpes simplex keratitis was essentially flat, showing no central progression. None of the eight patients with herpes simplex keratitis had a sensation recorded further than 0.5 mm from the wound margin.

Cornea↗
PubMed1987

Immunopathology and electron microscopy of Acanthamoeba keratitis.

In order to evaluate the local cellular immune response to Acanthamoeba infection we performed immunohistochemical examinations of the corneal buttons of two patients with Acanthamoeba keratitis. We found that the corneal stroma was infiltrated with polymorphonuclear leukocytes and HLA-DR positive macrophages that appeared to be stromal keratocytes by light microscopy. Despite the presence of chronic inflammation in both patients, no stromal lymphocytes were seen in one patient and a sparse lymphocytic infiltrate was seen in the other patient. Electron microscopy confirmed the presence of macrophages, neutrophils, and Acanthamoeba organisms in these two patients.

Adult↗
PubMed1987

Recent developments in dry eye management.

A concise review of current knowledge in the stimulation and regulation of tear production and its relationship to the ocular surface is presented. A discussion of treatment modalities, their benefits and drawbacks, follows. An approach to developing a rational treatment plan in the management of dry eyes is suggested with specific strategies. The application of these principles and the use of specific treatment modalities to manage the discreet manifestations of dry eye syndrome can lead to successful management in the majority of cases, with the preservation of useful vision and the relief of symptoms.

Combined Modality Therapy↗
PubMed1987

Corneal rim cultures.

We performed a retrospective analysis of 291 consecutive scleral rim cultures, taken at the time of corneal transplantation, from 1981 to 1986. There were 82 positive cultures (39%), and the most common pathogen was Staphylococcus epidermidis, with 24 positive cultures (30%). Ten of these (42%) were resistant to gentamycin. There were no cases of endophthalmitis or other infections in the immediate postoperative period. We also found 15 positive cultures of Streptococcus viridans. Of these, 13 (87%) were resistant to gentamycin but sensitive to most other antibiotics. Even though endophthalmitis is rare following penetrating keratoplasty, the emergence of resistant strains of Streptococcus viridans and Staphylococcus epidermidis suggests that eyebanks need to consider the addition of a second antibiotic to their MK medium.

Cornea↗