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S D Baumgartner

Publications and source records attributed to S D Baumgartner.

11 recordsLinked to original sources
PubMed1986

Combined morphologic effects of cryolathing and lyophilization on epikeratoplasty lenticules.

A correlative microscopic analysis of factory-prepared epikeratoplasty lenticules, corneas stored in McCarey-Kaufman medium for two to four days, and fresh human corneas disclosed ultrastructural abnormalities in Bowman's membrane and in the corneal stroma of the lyophilized lenticules that were not present in the control corneas. These features included mottling of Bowman's membrane, with large interfibrillar spaces; a roughness to its surface; and wide interlamellar lacunae within the corneal stroma, with significant changes in interfibrillar collagen distance and fibril diameter. The morphologic features of a clinical specimen excised three months following myopic epikeratoplasty were similar to those found with the factory-prepared lenticules. Our patient's corneal curvature steepened almost 3 diopters following lenticule removal. Our results suggest that additional studies of lyophilized epikeratoplasty lenticules should be performed.

Cornea↗
PubMed1985

Histopathology of a case of epikeratophakia (aphakic epikeratoplasty).

An epikeratoplasty button was removed by penetrating keratoplasty 31 months following an aphakic epikeratoplasty. The epithelium over the donor cap was thickened with numerous surface abnormalities. Bends and fractures in the donor Bowman's membrane were found throughout the length of the specimen. A significantly decreased number of keratocytes were found in the anterior half of the donor lenticule; the posterior half of the lenticule was acellular. The interfibrillar collagen distance of the donor lenticule was significantly increased compared with that of the recipient host cornea. The central thickness of the lenticule increased the total corneal thickness by 56%. Abnormal keratocytes were found in the underlying recipient corneal stroma. Based on this study, the histopathologic features of epikeratoplasty appear to be similar to those documented in the other lamellar refractive surgical procedures of keratophakia and keratomileusis.

Adult↗
PubMed1985

Refractive keratoplasty. Histopathology of clinical specimens.

Two keratophakia (KF), one epikeratophakia (EKP), three myopic keratomileusis (MKM), and three hypermetropic keratomileusis (HKM) specimens obtained 3.5 to 31 months following refractive keratoplasty were evaluated. The corneas were removed at keratoplasty due to postoperative complications, such as corneal edema, irregular astigmatism, delayed reepithelialization, stromal ulceration, epithelial interface ingrowth, and loss of visual acuity. The KF specimens demonstrated viable epithelium in the recipient-donor lenticule interface, disruption of the normal collagen lamellar pattern in the lenticule, and absence of keratocytes. All of the keratomileusis lenticules and the one epikeratophakia lenticule had variable keratocyte repopulation. All specimens showed irregular epithelial maturation. In one case of myopic keratomileusis, ferritin-like particles were found in the epithelial intercellular spaces. Folds in Bowman's membrane were seen in several keratomileusis lenticules; in one case, breaks in Bowman's membrane (BM) were seen.

Adult↗
PubMed1984

Alloplastic implants for the correction of refractive errors.

Convex-shaped, hydrophilic lenticles of various water content were implanted into microkeratome-dissected corneal pockets in a baboon model. Freshly trephined, cryolathed, and factory-lathed hydrogels were evaluated for periods exceeding 15 months, documenting clinical response, corneal curvature shifts, and morphologic features. Previously implanted hydrogels were subsequently removed, documenting the reversibility of the procedure while allowing the corneas to return to their preoperative condition. Various alloplastic materials were then reimplanted into the same intrastromal pockets. Medium and high water content lenses produced good results without affecting the recipient cornea, whereas thick or low water content materials extruded or produced severe anterior segment inflammation. The use of medium and high water content, convex-shaped lenticles for the correction of aphakia is possible using current techniques.

Animals↗
PubMed1984

Refractive keratoplasty: myopic keratomileusis in baboons.

We performed 8 myopic keratomileusis procedures in a baboon (Papio cynocephalus) model using the same instruments and techniques which are presently clinically employed. We requested 10 diopters of refractive correction and were able to achieve a mean keratometric correction of 5.5 diopters (range 2.4-8.4) in 6 eyes. Keratometric data in the two remaining eyes was not obtained, because of distortion of corneascope photographs. We did not encounter any technical problems at surgery or during the 2-1/2 to 6 month postoperative period of followup. Morphologic analysis demonstrated subclinical, focal breaks in Bowman's membrane in all specimens and keratocyte repopulation in 7 of 8 eyes. We did find a wide range in the central thickness of the excised corneas which can account for the undercorrections achieved. We consider the baboon model to be excellent for the evaluation of myopic keratomileusis.

Animals↗
PubMed1984

Morphology of hydrogel implants used for refractive keratoplasty.

The pathology of 14 keratophakia procedures in nine nonhuman primates using various hydrogel lenses as donor lenticles is presented. The lenses were treated as if they were human donor corneas using currently practiced keratophakia procedures. This included microkeratome resection of the recipient cornea, staining of the lenses before cryolathing and, in most instances, lathing according to a modified computer program after which the lenses were inserted into the previously dissected recipient lamellar bed. There was no histologic evidence of an inflammatory reaction to the hydrogels. The major pathologic feature was the presence of activated keratocytes lining the dissected intrastromal pockets.

Animals↗
PubMed1984

Epikeratophakia: clinical evaluation and histopathology of a non-human primate model.

We performed four aphakic and two myopic epikeratophakia procedures in a non-human primate model using two fresh and three prefrozen corneas and one glycerin-preserved cornea. The experiments were terminated 4 to 5 months postoperatively, and the eyes examined with correlative microscopy. The glycerin-preserved cornea sloughed and was not available for analysis. All but one prefrozen specimen demonstrated donor keratocyte repopulation. Active keratocytes were noted lining the optical interface. Focal areas of missing Bowman's layer were present in three recipient corneas. Epithelial interface ingrowth occurred in two specimens. The recipient corneas were otherwise normal.

Animals↗
PubMedDate not supplied

Infectious crystalline keratopathy: an electron microscope analysis.

A 73-year-old man developed a crystalline stromal keratopathy in one eye following his second corneal transplant. Despite aggressive treatment with antibiotics and antifungal agents, the lesion increased in size. A corneal transplant was performed and histopathologic studies were performed using both light and transmission electron microscopy. The characteristic trilamellar structure of a bacterial cell wall was found. The organisms were present only anteriorly. Small electron-dense bodies with needle-like projections were found. These bodies may be responsible for the crystalline appearance of this keratopathy. The appearance of a crystalline keratopathy should alert clinicians to the possibility of a low-grade bacterial infection. After appropriate cultures, we advise early and aggressive therapy with appropriate antibiotics.

Aged↗