Étude en microscopie confocale in vivo des bulles de filtration après chirurgie du glaucome

In vivo laser scanning confocal microscopy of the ocular surface in glaucoma

Over the past decade, knowledge about the ocular surface in glaucoma has significantly increased through the use of in vivo laser scanning confocal microscopy (LSCM). This in vivo imaging method can show modifications at the cellular level induced by anti-glaucoma drugs on ocular surface structures and adnexa in the eye. High-quality images of the conjunctiva, cornea, limbus, meibomian glands, and lymphoid structures during therapy can be obtained. In addition, LSCM opened new fields of research on the patho-physiology of aqueous humor (AH) hydrodynamics in untreated, and in medically or surgically treated glaucomatous patients. In these conditions, an enhancement of the trans-scleral AH outflow contributed to clarification of the mechanism of action of different anti-glaucoma medications and surgical approaches. Finally, the use of LSCM represented a huge advance in evaluation of bleb functionality after filtration surgery, defining the hallmarks of AH filtration through the bleb-wall and distinguishing functional from nonfunctional blebs. Thus, signs seen with LSCM may anticipate clinical failure, guiding the clinician in planning the appropriate timing of the various steps in bleb management. In this review we summarize the current knowledge about in vivo LSCM of the ocular surface in glaucoma.

Evaluation of filtering blebs using the 'Wuerzburg bleb classification score' compared to clinical findings

BACKGROUND

To determine the agreement between intraocular pressure and the 'Wuerzburg bleb classification score', as well as between single items of the score and intraocular pressure. Interobserver variability was analyzed.

METHODS

57 post-trabeculectomy eyes were included. Colour photographs were used to score the filtering bleb in accordance to the Wuerzburg bleb classification score by two different examiners. At the same visit, clinical data such as intraocular pressure, best corrected visual acuity, slit lamp biomicroscopy and medical history were obtained by another examiner.

RESULTS

After trabeculectomy, 42 out of 57 eyes (73.7%) reached the target pressure (≤ 21mmHg, and intraocular pressure reduction of at least 20%, without antiglaucoma medication, and without any additional intervention). Fair agreement was found between intraocular pressure and Wuerzburg bleb classification score ≥ 8 points and ≥ 7 points (kappa 0.24 and 0.27, respectively). Analyzing the subgroups of the morphological criteria, best agreement was found between occurrence of microcysts and target intraocular pressure (к 0.22-0.34).

CONCLUSIONS

Evaluating filtering blebs after trabeculectomy by using the Wuerzburg bleb classification score is a good technique for predicting intraocular pressure control in eyes attaining a minimum score of seven points. The presence of microcysts on the filtering bleb predicts that the eye is likely to attain target pressure.

Apport de la microscopie confocale in vivo à l’étude des ptérygions

PURPOSE

To describe the pterygium structure with a high-resolution in vivo confocal microscope and to show the typical components of active pterygium.

METHODS

In this study, 15 patients with 20 pterygia were examined. None of them had had prior pterygium surgery. Slit lamp examination and in vivo confocal microscopy imaging (Heidelberg Retina Tomograph II Rostock Cornea Module) were performed.

RESULTS

The images obtained consisted of two-dimensional high-resolution optical sections. We could identify the pterygial epithelium and its border, pterygial stroma and its vascularization, the pterygium corneal limits, and numerous inflammatory cells in active pterygia.

DISCUSSION

Many reports have been written about pterygium structure. In vivo confocal microscopy imaging is a new approach to this pathology and provides a precise evaluation of active pterygium.

[Contribution of confocal microscopy and anterior chamber OCT to the study of corneal endothelial pathologies]

PURPOSE

To describe the appearance of various endothelial diseases with in vivo confocal microscopy and anterior chamber optical coherence tomography (AC OCT).

METHODS

In this study, ten patients with five different corneal endothelial pathologies were evaluated. Three patients had cornea guttata, three had corneal endothelial precipitates, two had irido-corneo-endothelial (ICE) syndrome, one had endothelial folds, and one had breaks in the Descemet membrane. All patients had bilateral ophthalmologic examinations, in vivo confocal microscopy, and AC OCT analysis.

RESULTS

In cases of cornea guttata, AC OCT showed a finely embossed line corresponding to the empty intercellular cavities found with in vivo confocal microscopy. Corneal endothelium precipitates had the aspect of round formations suspended with the endothelium. Iris atrophy and irido-corneal synechiae resulting from ICE syndrome were precisely visualized with the AC OCT.

CONCLUSION

High-resolution images of the anterior segment could be obtained using the AC OCT. Associated with in vivo confocal microscopy, these two new imaging techniques provide a precise evaluation of endothelial pathologies.

[Utility of the Visante OCT in the follow-up of glaucoma surgery]

PURPOSE

To evaluate the utility of the Visante OCT in the follow-up of filtering surgery.

MATERIAL

and methods: In this study, we evaluated 38 filtering blebs in 31 patients following trabeculectomy (4) and nonpenetrating deep sclerectomy (NPDS). In 11 cases, mitomycin C was used during surgery. In patients who underwent NPDS, a collagen implant was placed within the scleral site in eight eyes and seven eyes had goniopuncture during follow-up. All patients had complete ophthalmologic examination with morphological evaluation of the bleb and intraocular pressure measurement as well as Visante OCT evaluation.

RESULTS

The trabeculectomy site as well as the trabeculodescemetic membrane (in NPDS), the scleral flap, the conjunctival flap, the iris, and the relationship between these structures were analyzed. Functioning blebs had a hyporeflective and irregular conjunctival tissue associated with a route for aqueous humor under the scleral flap from the anterior chamber toward the subconjunctival space. This filtration route was also observed within nonfunctioning encapsulated blebs. Flat and encapsulated nonfunctioning blebs had dense and hyperreflective conjunctival tissue. In the particular case of nonfunctioning flat blebs, there was no route for aqueous humor filtration under the scleral flap.

CONCLUSION

The Visante OCT is a simple and noninvasive imaging technique with good resolution, allowing the analysis of morphologic changes occurring in eyes after filtering surgery.

[In vivo confocal microscopy and ocular surface diseases: anatomical-clinical correlations]

PURPOSE

To describe corneal and conjunctival epithelial changes in various ocular surface disorders with a new in vivo confocal microscope (Corneal HRT II module) and to compare these results with those obtained by immunohistology on impression cytology specimens.

METHODS

In this study, we investigated 36 eyes of 18 patients with ocular surface diseases such as corneal epitheliopathy induced by ocular rosacea (five patients), keratoconjunctivitis sicca related to tear evaporative condition in Meibomian gland dysfunction (eight patients), or tear-deficient dry eye in Sjögren's syndrome (five patients). In vivo confocal microscopy imaging (Heidelberg Retina Tomograph II Rostock Cornea Module) and impression cytology of the cornea and/or conjunctiva were performed. The images were analyzed for epithelial cell morphology at nuclear and cytoplasmic levels, in the cornea and the conjunctiva, number of goblet cells and their possible presence within the corneal epithelium, corneoconjunctival junction at the limbus, and density and presence of inflammatory cells within both epithelia.

RESULTS

Images obtained consisted of two-dimensional 400x400 microm optical sections oriented parallel to the surface of the eye and compared with impression cytology. Conjunctival and corneal epithelia showed dramatic changes in ocular surface disease. In keratoconjunctivitis sicca, we found squamous metaplasia, inflammatory cell infiltration, goblet cell depletion, as well as a nuclear snake-like chromatin pattern. In rosacea associated with corneal epitheliopathy, a corneal conjunctivalization (goblet cells together with conjunctival epithelial cells within the corneal epithelium layer) was found. The images provided by this technique are in excellent correlation with the findings using impression cytology.

CONCLUSION

The HRT II in vivo confocal microscope facilitates the study of both central and peripheral ocular surface epithelia compared to first-generation confocal microscopy devices. In vivo confocal microscopy, showing corneal and conjunctival epithelial structures in the live eye at the cellular level, is likely to open up a new promising way to investigate ocular surface involvement in complex diseases, providing a new insight on corneal and conjunctival disorders in the future.

In Vivo Confocal Microscopy of Failing and Functioning Filtering Blebs

PURPOSE

To correlate clinical filtering bleb function with characteristics as detected by in vivo confocal microscopy.

METHODS

In a case-matched cross-sectional study, 52 eyes of 48 patients were examined 1 day to 12.8 years after primary trabeculectomy (mean 375 d). The patients were examined clinically and by in vivo confocal microscopy (Rostock Cornea Module/Heidelberg Retina Tomograph II, Heidelberg Engineering, Inc, Heidelberg, Germany). Nine early and 17 late functioning blebs were pair-matched with malfunctioning blebs. Stromal fiber patterns, the number of intraepithelial and stromal cystic spaces, and the amount of cellular infiltrates were evaluated.

RESULTS

Four stromal patterns (trabecular, reticular, corrugated, compacted) invisible to slit-lamp biomicroscopy could be distinguished by in vivo confocal microscopy. The trabecular pattern occurred only in functioning blebs, particularly early postoperatively. Intraepithelial cystic spaces were associated with functioning late blebs, whereas they were equally distributed in early blebs. In contrast, stromal cystic spaces indicate function in early blebs, whereas in late blebs the number of these cavities was similar in both groups. The density of intraepithelial and stromal round cells was higher in functioning late blebs compared with malfunctioning late blebs.

CONCLUSIONS

In vivo confocal microscopy allows to assess filtering bleb structures that are invisible biomicroscopically. Some morphologic features detected by this technique seem to indicate filtering bleb function and time after surgery. The predictive value of these features deserves further clarification in a prospective longitudinal study.

Clinical corneal confocal microscopy

Confocal microscopy allows non-invasive in vivo imaging of the ocular surface. Its unique physical properties enable microscopic examination of all layers of the cornea and have been used to investigate numerous corneal diseases: epithelial changes, numerous stromal degenerative or dystrophic diseases, endothelial pathologies, corneal deposits, infections, and traumatic lesions. It offers a new approach to study the physiological reactions of the cornea to different stimuli and the pathophysiologic events leading to corneal dysfunction in certain diseases. Confocal microscopy proves to be a powerful diagnostic tool and is especially of value in certain corneal diseases by allowing straightforward and non-invasive recognition of the pathologic conditions.

Comparative anatomy of laboratory animal corneas with a new-generation high-resolution in vivo confocal microscope

PURPOSE

The aim of the current study was to compare the corneas of three commonly used laboratory animals with a new in vivo confocal microscope.

METHODS

Six eyes of three adult male New Zealand albino rabbits, six eyes of three adult male Lewis rats, and six eyes of three adult male Swiss mice were used in this study. Corneas were analyzed in vivo using the Rostock Cornea Module of the Heidelberg Retina Tomograph (HRT)-II. For all eyes, 20 confocal microscopic images of each layer, that is, the superficial and basal corneal epithelia, the Bowman layer, the anterior and posterior stroma, and the endothelium, were recorded. The images were then analyzed qualitatively and compared among animals. Cellular densities of anterior and posterior stroma keratocytes of rabbits and endothelium density of the three different animals were also measured and compared.

RESULTS

The Rostock Cornea Module of the HRT II was successfully used to analyze all corneal layers of these three commonly used laboratory animals. Although the cellular patterns of the corneal layers of these three animals, as observed with in vivo confocal microscopy, were quite similar, some differences were seen in terms of endothelial cell density and stroma appearance. Superficial cells were seen as hyper- and hyporeflective polygonal cells. Basal cells had dark cytoplasm without visible nuclei and were closely organized. A Bowman layer was observed in all three animals as an amorphous tissue containing fine subepithelial nerve plexus. In rabbits, the stroma consisted of an amorphous ground substance with hyper-reflective structures corresponding with keratocyte nuclei. In rats and mice, numerous reflective stellate structures with no clearly visible nuclei were observed within the stroma. Besides endothelial cell density, the endothelium was similar among the three animals and was seen as hyper-reflective cells with dark limits organized in a honeycomb pattern.

CONCLUSIONS

The Rostock Cornea Module of the HRT II can provide high-resolution images of all corneal layers of rabbits, rats, and mice without sacrificing animals or preparing tissue. This new device may be useful for evaluating the cornea during experimental animal studies.

Apport de la microscopie confocale in vivo dans l’exploration de tumeurs limbiques

PURPOSE

To explore tumors of the limbus with a new in vivo confocal microscope and to compare the images to histology results.

METHODS

We evaluated three tumors in three patients with the Heidelberg Retina Tomograph II, Rostock Cornea Module. A diagnostic and therapeutic excision with adjunctive cryotherapy was performed for each individual. Confocal microscopy was compared to histopathologic sections.

RESULTS

Histology identified two dysplasias and one carcinoma in situ. The main pathological features were visible on our images: cytonuclear atypias, epithelial folds into an inflammatory and vascularized conjunctival stroma, fine vessels perpendicular to the surface, a clear limit with normal epithelium, papillomatous organization, and abnormal keratinization.

CONCLUSION

Our preliminary study showed that this type of limbal tumor could be explored using in vivo confocal microscopy. We were not able to determine whether there was a microinvasion. This new method could be a diagnostic aid, especially for atypical lesions and for follow-up because of frequent recurrences. Other studies are necessary to confirm our hypothesis.

In vivo confocal microscopy study of blebs after filtering surgery

OBJECTIVE

To analyze bleb structure after filtering surgery at the cellular level using a new generation in vivo confocal microscope.

DESIGN

Observational case series.

PARTICIPANTS

We retrospectively evaluated 17 filtering blebs of 13 patients after trabeculectomy.

METHODS

Ophthalmologic examinations included slit-lamp examination, applanation tonometry, and in vivo confocal microscopy (Heidelberg Retina Tomograph II, Rostock Cornea Module). Eyes were classified into 3 groups: (1) functioning blebs (6 eyes), (2) nonfunctioning blebs (6 eyes), and (3) functioning blebs after application of mitomycin C (5 eyes). Cellular patterns, morphologic appearance, and functional aspects of functioning and nonfunctioning blebs were compared in a masked manner.

MAIN OUTCOME MEASURES

In vivo confocal microscopy images were analyzed for number of intraepithelial microcysts, density of subepithelial connective tissue, presence of blood vessels, or encapsulation.

RESULTS

All functioning blebs had numerous intraepithelial optically-empty microcysts, whereas all nonfunctioning blebs had none or few. Subepithelial connective tissue was widely spaced in all functioning blebs, whereas the tissue was dense in 83.3% of nonfunctioning blebs. Functioning blebs with mitomycin C had numerous microcysts and loosely arranged subepithelial connective tissue as compared with nonfunctioning blebs.

CONCLUSIONS

In vivo confocal microscopy study of blebs is an original method that agrees well with ex vivo histologic examination. The number of microcysts and the density of the subepithelial connective tissue observed with in vivo confocal microscopy are correlated with bleb function. By providing details of the structures of filtering blebs at the cellular level, in vivo confocal microscopy constitutes a new promising way to understand wound healing mechanisms after filtering surgery.