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Biomedical subjects

F M Polack

Publications and source records attributed to F M Polack.

At least 19 recordsLinked to original sources
PubMed1989

Ultrastructural changes in the posterior layers of the cornea in Schnyder's crystalline dystrophy.

A case of central crystalline dystrophy of Schnyder is presented in which ultrastructural studies were performed on the corneal specimen after penetrating keratoplasty. Electron microscopic changes were documented not only in the anterior but in the posterior stroma and in the corneal endothelium. In the posterior stroma and at the interface between the stroma and Descemet's membrane, numerous ovoid, electron-lucent spaces were present that most likely represented foci of lipid deposition. In addition, rare, focal areas of endothelial cell degeneration were observed that produced minute discontinuities in the endothelial cell covering of Descemet's membrane. Changes in the posterior layers of the cornea in Schnyder's crystalline dystrophy may contribute to the comparatively poorer surgical results obtained with lamellar rather than full-thickness grafts in these cases.

Cornea↗
PubMed1989

Pseudophakic corneal edema. An 11-year study of its development, incidence, and treatment.

This paper studies the appearance and development of pseudophakic corneal edema (PCE) in a series of 840 patients referred for keratoplasty for corneal edema. There were no cases of PCE in 100 eyes with corneal edema studied between 1960 and 1970. In 200 cases of corneal edema studied between 1978 and 1980, there were 30 eyes with PCE (15%). The disease has gradually increased to 56% of all cases of corneal edema seen in 1986. A tendency of PCE to decrease has been noted in the last 2 years. The high incidence of PCE in recent years, which is the main reason for keratoplasty today, seems to be related to the use of closed loop anterior chamber lenses. Fuchs' dystrophy, which formed the bulk of cases of corneal edema, may be present in many cases of PCE. results of keratoplasty with intraocular lens (IOL) removal or exchange provided better than 80% good results in a group of 230 cases followed from 1 to 7 years with visual improvement better than 20/100 in over 50% of cases. The removal of an intraocular lens causing progressive visual symptoms is advised even at the risk of causing corneal edema.

Anterior Chamber↗
PubMed1988

Results of keratoplasty for aphakic or pseudophakic corneal edema with intraocular lens implantation or exchange.

This paper reports the results of 99 penetrating keratoplasties for aphakic and pseudophakic corneal edema using a single-piece, semielastic anterior chamber lens. There were 24 patients with aphakic corneal edema and 75 with pseudophakic corneal edema. Most cases had history compatible with macular disease. A Cilco-Kelman multiflex anterior chamber lens was used in all cases. All intraocular lenses were removed from pseudophakic eyes (38 iris supported lenses and 37 anterior chamber lenses). Preoperative glaucoma was present in over 20% of all cases. Grafted eyes were followed from 1 to 5 years. There were 24 clear grafts in aphakic eyes (87%) and 72 in pseudophakic eyes (96%). Visual improvement occurred in 30% of aphakic eyes and in 10% of pseudophakic eyes. In 50% of both groups, vision improved to better than 20/100. The study shows that the use of this type of anterior chamber lens did not affect the outcome of corneal grafts, and that there were no differences in graft results between the two groups. Visual acuity results were related to retinal changes.

Aged↗
PubMed1988

Aspergillus panophthalmitis complicating treatment of pterygium.

A 58-year-old woman lost her left eye due to Aspergillus panophthalmitis four months after excision of a pterygium. The patient had received postoperative beta radiation and developed a scleral ulcer in the area of treatment from which no organisms could be cultured on two occasions. Because of the difficulty of diagnosing superficial mycotic infections of the eye, and because the treatment of so-called radiation scleritis may worsen fungal infections, ophthalmologists need to be aware of the potential infectious complications associated with the treatment of pterygia.

Aspergillosis↗
PubMed1988

Glaucoma in keratoplasty.

This paper reports intraocular pressure findings in 676 eyes that received penetrating keratoplasties. There were four groups: 1. keratoconus without preoperative glaucoma (75 cases); 2. Fuchs' dystrophy and cataract (triple procedure) without glaucoma (260 cases); 3. aphakic eyes with or without intraocular lenses (204 cases); and 4. pseudophakic eyes with or without intraocular lens removal (137 cases). The last two groups had a significant number of glaucoma cases. All were controlled before surgery. There were no early or late glaucoma cases in the first group. A few cases with triple procedures had mild early intraocular pressure elevation. Thirty percent of aphakic eyes and 52% of pseudophakic eyes had early glaucoma. Twenty percent and 25% of these two groups had persistent glaucoma. Preoperative glaucoma eyes were included in these long-standing glaucoma cases.

Acetazolamide↗
PubMed1986

Graft rejection and glaucoma.

Four patients (three women and one man, 30 to 63 years old) developed increased intraocular pressure during graft rejection reactions. The increased intraocular pressure returned to normal in one case after successful treatment of the immune reaction but a second patient required antiglaucoma medication for a short period. Two patients with previous intraocular inflammation or anterior segment changes developed severe glaucoma and required long-term antiglaucoma medication. One patient was a corticosteroid-responder and eventually required filtering surgery.

Adrenal Cortex Hormones↗
PubMed1985

Fluorescein angiography of soft contact lens induced vascularization in penetrating keratoplasty.

Soft contact lenses after penetrating keratoplasty have become more popular as improved materials with high water content and high oxygen permeability have become available. However, aphakic patients who have undergone penetrating keratoplasty seem to be at high risk for development of graft vascularization when extended wear soft lenses are used for optical correction. This report, to our knowledge, is the first to use corneal fluorescein angiography to study contact lens induced vascularization. Corneal fluorescein angiography, in two cases, showed that vascularization was often more extensive than clinically apparent. Further, these "new" vessels, in both cases, were shown to be "leaky." This great degree of leak contributed to graft edema in both and possibly, in one case, to graft rejection. These findings suggest that care in fitting and careful follow-up is necessary in any graft patient fit with an extended wear lens and that delicate or problem patients may be better aided with other forms of optical correction. Further, this report shows the value of corneal fluorescein angiography as a useful tool in the study of vascularization of the cornea from any cause.

Aged↗
PubMed1980

Isolation of the plasma membrane from corneal endothelial cells.

The plasma membtanes of normal rabbit endothelail cells were isolated by the use of an aqueous two-phase polymer system. The membrane fraction was identified by electron microscopy, and a fivefold to eightfold increase in the specific activity of two plasma membrane markers. Na+-K+-ATPase and 5'nucleotidase was found. Recovery of the enzyme markers averaged 45% and 22%, respectively. Analysis of the purified membranes for glucose-6-phosphatase, a marker for endoplasmic reticulum, showed no contamination by this structure. This method for cell membrane characterization is promising in determining the enzymatic alterations of diseased corneas.

Adenosine Triphosphatases↗
PubMed1979

Scanning electron microscopy of congenital corneal leukomas (Peters' anomaly).

Specimens of three corneas in two patients with Peter's anomaly were obtained at the time of penetrating keratoplasty and studied by scanning and transmission electron microscopy. In one patient, the anomaly was monocular, and the endothelial surface showed a central defect in Descemet's layer with isolated rounded defects in the midperiphery. Fine collagenous material covered the posterior surface. The other two specimens were obtained from a patient with rubella syndrome without cataracts. The cornea showed malformation of Descemet's membrane with fibroblastic overgrowth on the endothelial layer. Epithelial-like cells and leukocytes were also found. The congenital central leukoma we believe was caused by adhesion of the pupillary membrane in our first patient, and possibly was inflammatory in our second patient.

Cornea↗
PubMed1979

[Ocular pathology related to intraocular lenses (author's transl)].

This study describes the ultramicroscopic alterations in several types of intraocular lenses removed from eyes with persistent ocular inflammation or elevated intraocular pressure. In some instances the alterations found in the lens material could have caused ocular disease. The corneal edema present in eyes with intraocular lenses sometimes is related to trauma at the trauma at the time of intraocular lens implantation. In most cases the alterations are similar to those found in Fuchs' dystrophy. The presence of warts in Descemet's membrane indicate previous corneal pathology, an obvious contraindication to the use of these devices.

Cornea↗
PubMed1978

Autoradiographic study of retrocorneal membranes.

Fibrous membranes in the posterior cornea occur in failed transplants. The purpose of these studies was to investigate the role of corneal endothelium in the formation of these membranes. The corneal cellular components of rabbit corneas were labeled with tritiated thymidine. Labeled rabbit corneal stroma was replaced with unlabeled tissue (pre-Descemet's lamellar graft), leaving only labeled endothelium. Weeks later small unlabeled penetrating grafts, without endothelium, were placed inside this lamellar graft. The surrounding labeled host endothelial cells were found in a fine retrograft membrane and in the scar of grafts. The experiment demonstrated that host endothelial cells participate in the formation of retrograft membranes, but it does not exclude other origin of fibroblasts.

Animals↗