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A longitudinal case series investigating cellular changes to the transplanted cornea using confocal microscopy.

PURPOSE: To perform a longitudinal evaluation of subjects who had undergone penetrating keratoplasty, using slit scanning confocal microscopy. METHODS: In vivo confocal microscopy was used to evaluate the central cornea of four subjects who had recently undergone penetrating keratoplasty. Subjects were examined on four occasions over a 12-month period after surgery. Quantitative and qualitative aspects of corneal morphology were compared against data from normal control subjects. RESULTS: The epithelium varied in appearance between subjects and took at least 12 months to return to a similar arrangement to that seen in normal eyes. Bowman's layer was viewed as an acellular layer immediately after surgery with no evidence of nerve fibres, although nerve components were apparent 12 months after surgery. Stromal nerves were not visible immediately after surgery. One year following penetrating keratoplasty there was evidence of thin nerves running a straight course through the central stroma. Keratocyte density in the anterior and posterior stroma was lower in the transplanted cornea but appeared to remain constant over a period of 1 year. Activated keratocytes were seen in the anterior stroma of all subjects; they appeared to be responsible for significant levels of corneal haze. The time period within which this keratocyte activation occurred varied between individuals. Endothelial cell density decreased at an accelerated rate over the 12-month period. CONCLUSIONS: Confocal microscopy allows cellular changes to be monitored in vivo following penetrating keratoplasty and may assist clinicians in understanding postoperative recovery.

Adult↗

Confocal microscopy: principles and applications to the field of reproductive biology.

Confocal microscopy allows analysis of fluorescent labeled thick specimens without physical sectioning. Optical sections are generated by eliminating out-of-focus fluorescence and displayed as digitalized images. It allows 3-dimensional reconstruction (XYZ) and time-analysis (XYT), thus providing unique chance to link morphology with cell function. Since images are obtained by scanning, excess illumination of the specimen and quick decrease of the fluorescent signal are avoided. Resolution obtained with a Laser Scanning Confocal Microscopy (LSCM) is theoretically better than that of a conventional microscope. The preparation of the specimen may be based on standard techniques, such as immunocytochemistry applied to fixed cells, or on staining of living cells, following the use of different fluorescent probes at the same time (colocalization). In our laboratory, we use the LSCM system Fluoview version 2.1 (Olympus) to study reproductive biology of animals and humans. We work on stainings of oocytes and blastocysts (mouse, bovine, human), and human ovarian tissues. We study mitochondrial distribution, cortical granule migration, calcium oscillations and spindle quality to link culture conditions and oocyte quality. Staining of F-actin is used to check transzonal projections (in zona pellucida) or to detect abnormalities following experimental treatment. Blastocyst quality is analyzed in sequential optical sections for microfilament organization and counting of total cell number (staining with phalloidin (actin) and picogreen (DNA). Trophectoderm and inner cell mass distribution (differential staining), apoptotic cells (TUNEL method) and viable cells (live/dead test) are also evaluated. Confocal imaging can be helpful for rapid determination of follicle density (staining with AM Calcein) and follicle morphology (picogreen) in ovarian cortical biopsies. The current review describes the principles of confocal microscopy and illustrates its applications to the field of reproductive biology by a large collection of pictures.

Animals↗

Evaluation of intrastromal lipid deposits after intacs implantation using in vivo confocal microscopy.

PURPOSE: To assess the structure and location of intrastromal lipid deposits after implantation of Intacs by using in vivo confocal microscopy. METHODS: Seven eyes of six patients were examined by in vivo confocal microscopy 5 years (n = 6) or 2 months (n = 1) after uncomplicated implantation of Intacs for the correction of mild myopia. Selected images from all corneal layers were qualitatively evaluated for structural changes, with special attention paid to areas surrounding the Intacs implants. RESULTS: In the peripheral cornea of eyes examined 5 years after surgery, epithelial and endothelial cell layers appeared normal. Tandem scanning confocal microscopy showed stromal haze surrounding the implants in all eyes examined, but no keratocyte activation was seen. Reflective amorphous or crystalline structures consistent with lipid deposition were detected in all eyes with long-term implantation of Intacs. Deposits were localized to the inner and outer edges of Intacs segments and to the region anterior to the implant. Confocal microscopy did not show any deposits in the eye examined 2 months after surgery, although the region anterior to the implant appeared hazy and edematous. Areas central to the implant appeared normal in all eyes. CONCLUSIONS: The mechanical and physiologic stresses introduced by the implantation of Intacs lead to the accumulation of lipid deposits in the extracellular matrix. By using in vivo confocal microscopy, the location and structure of these deposits can be determined.

Adult↗

Imaging the microstructural abnormalities of meesmann corneal dystrophy by in vivo confocal microscopy.

PURPOSE: To delineate the microstructural features of Meesmann corneal dystrophy using in vivo confocal microscopy. METHOD: Three subjects with clinically diagnosed Meesmann corneal dystrophy were examined by slit-lamp biomicroscopy and slit-scanning in vivo confocal microscopy. RESULTS: On slit-lamp biomicroscopy, all subjects demonstrated large bilateral multiple epithelial cystic lesions extending to the midperiphery. On in vivo confocal microscopy, these lesions appeared as hyporeflective areas in the basal epithelial layer. The majority were circular, oval or teardrop shaped and ranged between 48 mum and 145 mum in diameter. Large elongated intraepithelial clefts were also seen. Reflective spots were visible within most of the lesions and these may represent the fibrillogranular material (termed peculiar substance) and tonofilament bundles observed in electron microscopy studies. An additional finding was the fragmented appearance of the subbasal nerve plexus. CONCLUSION: We present the first case series of Meesmann corneal dystrophy imaged by in vivo confocal microscopy and describe the associated microstructural features. Delineation of these features facilitates the use of the confocal microscope to aid diagnosis and management of corneal dystrophies.

Corneal Dystrophies, Hereditary↗

In vivo confocal microscopy of the ocular surface.

Over the past two decades, the applications of in vivo confocal microscopy to the investigation of ocular surface diseases in the living eye have been greatly extended. Confocal microscopy enables detailed investigation of tarsal and palpebral conjunctiva, central and peripheral cornea, tear film, and lids, and it allows evaluation of the ocular surface at the cellular level. High-quality imaging in both contact and noncontact modes has allowed new understanding of the functions of the ocular surface system, and in the coming years, such knowledge will become increasingly comprehensive and specific. Confocal microscopy may provide a link between well-established ex vivo histology and in vivo study of ocular pathology, not only in clinical science but also in clinical practice. The purpose of this review is to summarize the current knowledge about in vivo confocal microscopy of the ocular surface.

Conjunctiva↗

In vivo confocal microscopy after herpes keratitis.

PURPOSE: To describe the confocal microscopic findings, with special reference to corneal subbasal nerves, after herpes simplex virus (HSV) keratitis. METHODS: In this study, 16 HSV eyes and 14 contralateral eyes of 16 patients, diagnosed with unilateral HSV keratitis 1-12 months earlier by the presence of dendritic corneal ulceration or microbiologic confirmation, were examined by in vivo confocal microscopy for evaluation of corneal morphology. RESULTS: Herpes simplex virus eyes: In 2 eyes the surface epithelial cells appeared large, and no abnormalities were observed in the basal epithelial cells. In 2 eyes subbasal nerve fiber bundles were completely absent, in 3 eyes there was a reduced number of long nerve fiber bundles, and in 11 eyes the subbasal nerve plexus appeared normal. In 10 corneas, highly reflective dendritic structures were found at the level of the basal epithelial cells. Frequently these structures were found in the vicinity of stromal fibrosis. Areas with increased abnormal extracellular matrix were found in 11 eyes. Stromal nerves were not visualized in all corneas, but appeared normal when observed. Contralateral eyes: No abnormalities were observed in the epithelium. All corneas presented with a normal subbasal nerve plexus, but in 2 eyes dendritic particles were observed. Three corneas presented with activated keratocytes and increased amounts of abnormal extracellular matrix. CONCLUSIONS: When visualized by confocal microscopy, the subbasal nerve plexus appears relatively unaffected in cases with resolved HSV keratitis. Unidentified dendritic structures, presumably Langerhans cells, are frequently seen at the level of the basal epithelium in corneas with a history of herpetic disease.

Adolescent↗

Two-photon confocal microscopy: a nondestructive method for studying wound healing.

Two-photon confocal microscopy is a new technology useful in nondestructive analysis of tissue. The pattern generated from laser-excited autofluorescence and second harmonic signals can be analyzed to construct a three-dimensional, microanatomical, structural image. The healing of full-thickness guinea pig skin wounds was studied over a period of 28 days using two-photon confocal microscopy. Three-dimensional data were rendered from two-dimensional images and compared with conventional, en face, histologic sections. Two-photon confocal microscopy images show resolution of muscle, fascia fibers, collagen fibers, inflammatory cells, blood vessels, and hair. Although these images do not currently have the resolution of standard histology, the ability to noninvasively acquire three-dimensional images of skin promises to be an important tool in wound-healing studies.

Animals↗

In vivo and ex vivo virtual biopsy of the liver with near-infrared, reflectance confocal microscopy.

The assessment of liver architecture is an essential part of the understanding of its physiology and pathology. Current fluorescence confocal microscopy methods face numerous drawbacks, such as cytotoxicity, quenching effect, potential negative ino- and chrono-tropic effects and leaking of fluorescent agents through the sinusoid fenestrations. The recently developed, near-infrared reflectance confocal microscopy allows high-resolution optical sectioning through intact tissues, without employing fluorescent stains, while contrast between structures is provided by the natural refractivity of the tissue. The aim of this study is to assess the utility of near-infrared reflectance confocal microscopy in the evaluation of the hepatic microscopic architecture in vivo and ex vivo. Rat livers were noninvasively examined in vivo and ex vivo with near-infrared reflectance confocal microscopy. Two experimental contrast agents were subsequently used to enhance particular structures. Parenchymal and vascular structures are readily identified, as well as some intracellular details. Differences between in vivo and ex vivo states were also observed. The use of contrast agents also highlights certain morphologic structures. In conclusion, near-infrared reflectance confocal microscopy stands as a useful adjunct technique to the study of hepatic parenchyma offering details equivalent to, if not surpassing traditional light microscopy.

Animals↗

Confocal microscopy in cornea guttata and Fuchs' endothelial dystrophy.

AIMS: To report the appearances of cornea guttata and Fuchs' endothelial dystrophy from white light confocal microscopy. METHODS: Seven eyes of four consecutive patients with cornea guttata were prospectively examined. Of the seven eyes, three also had corneal oedema (Fuchs' dystrophy). In vivo white light tandem scanning confocal microscopy was performed in all eyes. Results were compared with non-contact specular microscopy. RESULTS: Specular microscopy was precluded by corneal oedema in one eye. In the remaining six eyes, it demonstrated typical changes including pleomorphism, polymegathism, and the presence of guttae appearing as dark bodies, some with a central bright reflex. In all seven eyes, confocal microscopy revealed the presence of round hyporeflective images with an occasional central highlight at the level of the endothelium. Changes in cell morphology and size were readily appreciated. CONCLUSION: By comparison with specular microscopy, the hyporeflective images with an occasional central highlight seen on confocal microscopy are consistent with the presence of guttae. Confocal microscopy may confirm the diagnosis of cornea guttata and Fuchs' endothelial dystrophy by demonstrating the presence of guttae. This technique is especially valuable in cases of corneal oedema, where specular microscopy may fail to visualise the endothelium. However, specular microscopy should remain the method of choice to evaluate the endothelium, principally because it is easier to use.

Adult↗

Microstructural analysis of Salzmann's nodular degeneration by in vivo confocal microscopy.

A 44-year-old man with symptoms of ocular irritation and corneal changes characteristic of Salzmann's nodular degeneration in the left eye was examined using in vivo confocal microscopy. In vivo confocal microscopy highlighted an irregularly shaped basal epithelium with foci of prominent nuclei, and disrupted anterior stromal architecture with increased reflectivity of extracellular matrix within the nodules. These observations were consistent with prior histopathological descriptions of Salzmann's nodular degeneration. In vivo confocal microscopy enhances the clinicopathological assessment of degenerative corneal diseases, such as Salzmann's nodular degeneration, without the need for biopsy.

Adult↗

Differential diagnosis of linear corneal images on confocal microscopy.

PURPOSE: This study aimed to detect corneal conditions presenting with linear images on white light confocal microscopy and to analyze their distinguishing characteristics. METHODS: In 1996 and 1997, 153 eyes of 110 patients with various corneal conditions were examined. In vivo examination of the cornea was performed by using a white-light tandem scanning confocal microscope. Images were captured by using a video camera and stored on S-VHS video tapes. In this retrospective study, patient charts and confocal microscopic video records were reviewed. Conditions with linear images were looked for, and the images were analyzed and compared. RESULTS: The only structures presenting as linear images on confocal microscopy in normal subjects consisted of corneal nerves. The following pathologic conditions also had linear images on confocal microscopy: corneal vascularization, mycotic keratitis, lattice corneal dystrophy, and posterior polymorphous dystrophy. Each condition could be identified based on its reflectivity, delineation, size, branching pattern, and location in the cornea. CONCLUSION: Different corneal conditions present with linear images on confocal microscopy. Correct identification is critical to avoid misdiagnosis.

Cornea↗

In vivo confocal microscopy of posterior polymorphous dystrophy.

PURPOSE: This study was designed to delineate the morphologic features of posterior polymorphous dystrophy (PPD) using in vivo confocal microscopy. METHODS: Six patients with clinically diagnosed PPD were examined by slit-lamp biomicroscopy, Orbscan II slit-scanning elevation topography, and in vivo confocal microscopy. RESULTS: Endothelial cell densities ranged from 613 to 3,405 cells/mm and endothelial polymegathism was noted in all cases, whereas endothelial pleomorphism was not a prominent feature. Three cases exhibited bright endothelial nuclei. A variety of abnormal curvilinear and vesicular abnormalities were imaged by in vivo confocal microscopy, with lesions ranging between 6 and 159 microm in diameter. Abnormal endothelial cells were visible within some of these lesions. Six cases showed hyperreflectivity at the level of Descemet's membrane around the lesions. Deep stromal keratocytes appeared to aggregate around, or were compressed by, the endothelial lesions in one case. CONCLUSIONS: We report the largest case series of PPD imaged by in vivo confocal microscopy. The ability of in vivo confocal microscopy to assess the living cornea over time enables monitoring of disease progression and thus the potential to identify and correlate development of, or changes in, microstructural features. As more data become available, these analyses may enable the formulation of prognostic and diagnostic criteria.

Adult↗

In vivo confocal microscopy of fleck dystrophy.

PURPOSE: To use in vivo confocal microscopy to evaluate corneas with fleck dystrophy. METHODS: Both eyes of three patients with corneal fleck dystrophy were examined with a scanning slit confocal microscope. Corneal epithelium, stroma, and endothelium were evaluated, as well as the basal epithelial and stromal nerves. RESULTS: The epithelium did not show any anomalies, but the basal nerves showed hyperreflective inclusions. Throughout the entire stroma, hyperreflective dots of various shapes were seen. These consisted mostly of spherical matter with a diameter of 3-5 microm and were sometimes enclosed in cyst-like structures. The majority of the stromal cells and stromal nerves appeared normal. The endothelial cell layer was unaffected. CONCLUSION: In vivo confocal microscopy demonstrates previously unreported inclusions in the basal nerves of fleck dystrophy corneas. In addition to this new finding, the study confirms earlier histopathologic reports, demonstrating accumulation of pathologic material in the stromal cells.

Adult↗

Reflectance-mode confocal microscopy of pigmented skin lesions--improvement in melanoma diagnostic specificity.

BACKGROUND: In vivo confocal microscopy enables skin visualization with a quasihistopathologic resolution. OBJECTIVE: We sought to describe confocal features in melanocytic lesions and to evaluate their diagnostic significance for melanoma (MM) identification. METHODS: Thirty seven MMs, 49 acquired nevi, and 16 Spitz/Reed nevi, presenting equivocal clinicodermoscopic aspects were investigated by confocal microscopy. RESULTS: MMs and nevi significantly differed for some aspects. In multivariate analysis, the presence of nonedged dermal papillae, atypical cells, and isolated nucleated cells within dermal papilla, pagetoid cells, widespread pagetoid infiltration, and cerebriform clusters were strongly correlated with MM diagnosis. A receiver operating characteristic curve value of 0.952 was obtained. LIMITATIONS: Spitz/Reed nevi represented a pitfall in confocal diagnosis, owing to the frequent observation of pagetoid infiltration, architectural disarray, and cytologic atypia, and to the impossibility of evaluating cell maturation with depth. CONCLUSION: Characterization of confocal microscopy features of MMs and nevi seems to improve diagnostic accuracy for melanocytic lesions that are difficult to diagnose.

Diagnosis, Differential↗

Confocal microscopy as a tool for the investigation of the anterior part of the eye.

In recent years, confocal microscopy has become a powerful tool for examining microscopic structures in the living eye. The decisive advantage of this technique is that it permits the investigation of optical sections of relatively thick (> 10 microns) specimens. Because confocal microscopy suppresses the out-of-focus blur, sharp three-dimensional images with excellent resolution can be obtained. Confocal microscopy is therefore able to provide more information than the classic methods--i.e., specular microscopy and slit-lamp biomicroscopy. This paper reviews recent applications of confocal microscopy in three fields of ophthalmology: the observation of the anatomy of the anterior parts of the eye, the investigation of these structures after local administration of drugs and, finally, the use of this technique for the diagnosis of infectious ocular diseases.

Animals↗

Confocal microscopy of Aspergillus fumigatus keratitis.

AIM: To use a confocal microscope to characterise the treated and untreated courses of fungal keratitis. METHODS: In the first experiment, Aspergillus fumigatus stromal keratitis was produced in both eyes of seven New Zealand white rabbits. In the second experiment, keratitis was induced in right eyes of 20 rabbits. Group 1 rabbits were treated with topical fluconazole, group 2 rabbits received oral fluconazole, and group 3 rabbits were used as controls. The rabbits were examined with a slit lamp and confocal microscope 2, 6, 10, 14, and 20 days after inoculation. The corneal cultures were taken on days 2, 14, and 20 and biopsies were taken on days 2 and 22. RESULTS: On days 14 and 22 confocal microscopy was more sensitive than culture technique in both treated and untreated animals, since not all cases of fungal keratitis can be cultured. CONCLUSION: This study indicates that confocal microscopy is a rapid and sensitive diagnostic tool for both the early diagnosis and non-invasive follow up of fungal keratitis

Administration, Oral↗

Visualization of silver-enhanced reaction products from protein-and immuno-colloidal gold probes by laser scanning confocal microscopy in reflection mode.

We have employed a laser scanning confocal microscope in reflection mode to directly and indirectly visualize sites of deposition of silver-enhanced reaction products from colloidal gold probes. A direct approach was used for the localization of alpha-fetoprotein receptors in human myoblasts by incubating primary cultures with an alpha-fetoprotein-gold conjugate. For an indirect approach, cultured CEM cells, derived from a human T-lymphoma cell line, were incubated with a mouse monoclonal antibody to mature T-cells, followed by a gold-labelled antibody to mouse immunoglobulins. Multiple optical sections of each sample were collected by reflection laser scanning confocal microscopy and combined into three-dimensional renderings. A (non-confocal) transmission image was generated of each field for comparative purposes. The increasing use of reflection laser scanning confocal microscopy combined with colloidal gold conjugates as biological markers will probably be of considerable advantage in cytochemical analysis.

Antigens, CD↗

Localisation of connective tissue and inhibition of autofluorescence in the human optic nerve and nerve head using a modified picrosirius red technique and confocal microscopy.

The use of picrosirius red to localise connective tissue in thin tissue sections viewed by bright-field microscopy is well documented. Its use on thin tissue sections imaged by fluorescence confocal microscopy has also been reported. Here we describe modifications to published procedures that allow picrosirius red staining of thick 60-microm sections and their subsequent analysis by confocal microscopy. The use of phosphomolybdic acid pre-treatment was found to be essential for confocal analysis; in addition to preventing non-specific staining, it also quenched tissue autofluorescence. By incubating sections free-floating, pre-treating them with phosphomolybdic acid for 30 min and imaging them using an argon ion laser we were able to use confocal microscopy to image the entire depth of 60-microm human optic nerve and nerve head sections stained with picrosirius red. The application of this modified picrosirius red and confocal microscopy technique should be useful for analysing the three-dimensional structure of the optic nerve and other tissues with a similarly complex arrangement of connective tissue.

Adult↗