Intérêt du microscope confocal cornéen in vivo HRT2 pour l’étude de l’épithélium cornéo-conjonctival

Conjunctival flap covering combined with antiviral and steroid therapy for severe herpes simplex virus necrotizing stromal keratitis

Herpes simplex virus (HSV) necrotizing stromal keratitis is a common type of herpetic stromal keratitis (HSK). Antiviral medication alone cannot control the disease, and corticosteroid eye drops may aggravate the ulcer and result in corneal perforation. Amniotic membrane transplantation effectively treats superficial corneal ulcer resulting from necrotizing stromal HSK. However, the efficacy of this approach seems to be limited for more serious cases. This study presented the clinical treatment of severe HSV necrotizing stromal keratitis (ulcer depth greater than half of the corneal stroma) by conjunctival flap covering surgery in 25 patients (25 eyes) combined with antivirus and corticosteroid treatment at Shandong Eye Hospital from January 2007 to December 2013. Clinical results showed that the mean best spectacle-corrected visual acuity improved from preoperative 20/333 to postoperative 20/40 (P < 0.05). All patients recovered ocular surface stabilization. There was recurrence in two eyes, which was cured with antiviral medication. Conjunctival flap covering combined with antivirus and corticosteroid treatment is effective in treating severe HSV necrotizing stromal keratitis.

Assessment of keratocyte density in patients with keratoconus not using contact lenses

PURPOSE

To assess the keratocyte density (KD) in the cornea of patients with keratoconus not using contact lenses.

METHOD

In this pilot study, the eyes (n = 68) of 35 patients with the diagnosis of keratoconus, who did not use contact lenses and the eyes(n = 70) of 35 healthy controls were prospectively examined using the Heidelberg Retinal Tomography Rostock cornea module (HRT3/RCM). The cases with keratoconus and controls were compared with regard to KD in the anteroposterior stromal layers.

RESULTS

Of the cases with keratoconus, 15 (42.9%) were men and 20 (57.1%) were women. The mean age was 21.1 ± 11.1 (range =14-41) years. Of the controls, 26 (73.9%) were men and 9 (26.1%)were women. The mean age was 23.9 ± 12.9 (range = 14-35) years.Of the 68 eyes with keratoconus, 22 (28.2%) had mild keratoconus, 23 (35.9%) had moderate keratoconus, and 23 (35.9%) had severe keratoconus. The mean anterior stromal KD was 651.4 ± 89 cells per square millimeter in cases with keratoconus and 879.4 ± 75 cells per square millimeter in controls (P < 0.05). The mean anterior stromal KD decreased by 25.9% in corneas with keratoconus. The mean posterior stromal KD was found to be 363.6 ± 74 cells per square millimeter in cases with keratoconus and 469.7 ± 56 cells per square millimeter in controls (P< 0.01). The mean posterior stromal KD decreased by 22.6% in corneas with keratoconus. The anterior stromal KD was higher than the posterior stromal KD (P < 0.001). No significant relationships were found between the stromal KD data and central corneal thickness or steepest keratometric.

CONCLUSIONS

The KD in the anterior and posterior corneal stroma was decreased in patients with keratoconus, but without the use of contact lens, compared with healthy controls. This density difference was independent from the central corneal thickness and the stage of keratoconus.

Archipelago Keratitis

OBJECTIVE

To describe archipelago keratitis, a presumed clinical variant of herpetic epithelial keratitis.

DESIGN

Case series.

PARTICIPANTS

A series of 6 patients with an unusual form of superficial keratitis.

METHODS

History, including age, gender, clinical evolution, and treatment; slit-lamp biomicroscopy findings; in vivo confocal microscopy findings; and corneal epithelial scrapings were analyzed.

MAIN OUTCOME MEASURES

Clinical ocular examination, a diagnostic workup including corneal scraping for herpesvirus polymerase chain reaction, in vivo confocal microscopy, and therapeutic outcome.

RESULTS

The authors describe a series of 6 patients with keratitis consisting of foci of epithelial erosions associated with subepithelial nummular inflammatory infiltrates and disposed in a radial, centripetal, archipelagolike pattern originating from the limbus. All the patients had a past history of herpetic epithelial keratitis, herpetic vesicles on the ipsilateral lid, or both. Polymerase chain reaction-based screening for herpes simplex virus 1 and 2 in corneal scrapings demonstrated positive results in 2 patients. In vivo corneal confocal microscopy revealed focal areas of hyperreflective epithelial cells and hyperreflective subepithelial dendritic structures overlying activated keratocytes. All the patients improved with oral valacyclovir treatment followed by topical steroid therapy.

CONCLUSIONS

Archipelago keratitis may be a new clinical variant of herpetic keratitis, reflecting herpetic dissemination from the limbus to the center of the cornea.

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.

In Vivo Corneal Confocal Microscopy in Marfan Syndrome

PURPOSE

To examine the cornea of patients with Marfan syndrome in comparison with a control group by using the in vivo confocal microscope.

METHODS

Twenty-four eyes of 12 patients with Marfan syndrome had their corneas examined using the in vivo confocal microscope Heidelberg Retina Tomograph (HRT) II/Rostock Cornea Module. The control group included 24 eyes of 12 subjects who had their corneas examined by the same in vivo confocal microscope.

RESULTS

Epithelium and neural plexus examination did not show any difference between the 2 groups. Examination of the stroma showed no significant differences concerning the morphology and density of keratocytes. The extracellular matrix of 16 of the 24 eyes of the Marfan group was clearly visible and showed thin highly reflective interconnected lines between keratocytes. In the healthy eye group, reflective lines were observed in only 5 of the 24 eyes. The endothelium of 14 corneas of the Marfan group showed brightly reflective particles. In no cornea of the control group were such particles observed.

CONCLUSIONS

Highly reflective extracellular matrix of the stroma and brightly reflective particles among the endothelial cells were the 2 main corneal findings observed by using in vivo corneal confocal microscopy in patients with Marfan syndrome compared with a control group. Further studies need to be made to confirm these findings and eventually find new criteria for Marfan syndrome from the examination of in vivo corneal confocal microscopy.

Contact lens-induced changes in the anterior eye as observed in vivo with the confocal microscope

The availability of the confocal microscope over the past decade has allowed clinicians and researchers to refine their understanding of the physiological and pathological basis of the ocular response to contact lens wear, and to discover previously unknown phenomena. Mucin balls, which form in the tear layer in patients wearing silicone hydrogel lenses, can penetrate the full thickness of the epithelium, leading to activation of keratocytes in the underlying anterior stroma. Epithelial cell size increases in response to all forms of lens wear, with lenses of higher oxygen transmissibility (Dk/t) interfering least with the normal process of epithelial desquamation. A higher density of Langerhans' cells is observed in the layer of the sub-basal nerve plexus among contact lens wearers, suggesting that contact lens wear may be altering the immune status of the cornea. Dark lines and folds are observed in the oedematous cornea in response to contact lens wear. Mechanical stimulation of the corneal surface, due to the physical presence of a contact lens, and the consequent release of inflammatory mediators, is the likely cause of reduced keratocyte density associated with lens wear. Highly reflective stromal 'microdot deposits' are observed throughout the entire stroma in higher numbers in lens wearers. 'Blebs' in the endothelium have a bright centre surrounded by a dark annular shadow; this appearance is explained with the aid of an optical model. The confocal microscope has considerable clinical utility in diagnosing Acanthamoeba and fungal keratitis. At the limbus, contact lenses can induce structural changes such as increases in basal epithelial cell size. An increased number of rolling leucocytes is observed in limbal vessels in response to low Dk/t lenses. It is concluded that the confocal microscope has considerable utility in contact lens research and practice.

[Lacrimal film and the ocular surface]

Abnormalities of the ocular surface affect a large proportion of the general population. Symptoms depend on whether the lids, the corneoconjunctival surface, or the lacrimal layer are involved. The latter results from the balance of a fragile mixture of water, lipids, and mucus. Different circumstances can lead to the disruption of the lacrimal layer associated with dry-eye symptoms, eventually leading to inflammation. Alterations observed during dry-eye disease, meibomian dysfunction, allergic conjunctivitis, contact lens wear infectious conjunctivitis, or after refractive surgery are reviewed. Patient relief depends on a reliable analysis of the mechanism involved in the ocular surface disease.

[In vivo imaging of the conjunctival epithelium using confocal laser scanning microscopy]

BACKGROUND

In various ocular diseases, cytomorphological findings of the ocular surface are an essential component of clinical diagnostics. When evaluating the conjunctival epithelium, minimally invasive acquisition of biomaterial is necessary for lab and technical processing and in vitro histological examination. To examine corneal structures in vivo, confocal laser scanning microscopy is a successful standard method. Our aim was to employ in vivo confocal laser scanning microscopy also for examining the conjunctival epithelium.

MATERIAL AND METHOD

Results were analyzed and compared with cytomorphological findings of impression cytology. Accordingly, the basic features of conjunctival in vivo examination using RLSM were described and defined. In vivo images were analyzed and compared with impression cytological slide preparations (n=110) of 23 healthy test persons. Examination was standardized. Finally, the confocal laser scan images were compared to the impression cytological patterns.

RESULTS

Due to the distribution of reflectors (pixel brightness), diagnostic analysis of important morphological structures (cell nucleus, cytoplasm, nucleus/plasma relation) of the conjunctiva is possible. Secretory cells of the epithelium (goblet cells) can be easily recognized by their size. Highly reflective pixels depict cell walls or wide intercellular spaces with high contrast.

CONCLUSIONS

The in vivo investigation of important anatomical and morphological structures of the conjunctival epithelium is possible using RLSM. The distribution pattern of goblet cell pixel brightness may correlate with various secretion contents or suggest distinct, recognizable, functional conditions (hypo- or hypersecretion).

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.

Epithelial Basement Membrane Dystrophy

PURPOSE

To describe corneal changes in patients with epithelial basement membrane dystrophy (EBMD) using a new in vivo confocal microscope.

DESIGN

Observational case series.

METHODS

A retrospective chart review of 22 consecutive patients with EBMD at the Quinze-Vingts National Ophthalmology Hospital from April 2004 to March 2005 was conducted. Gender, age, history of painful episodes suggestive of recurrent erosions, best-corrected visual acuity, slit lamp findings, and in vivo confocal microscopy images were analyzed.

RESULTS

There were 8 male (36.4%) and 14 female (63.6%) subjects. Eighteen patients (81.2%) had a history of recurrent erosions in 1 or in both eyes. In 37 eyes of 19 patients (86.4%), map and/or dot and/or fingerprint changes were observed biomicroscopically. In 3 patients (13.6%) with recurrent erosions, the cornea had a normal structure on slit lamp examination and the diagnosis of EBMD was made after in vivo confocal microscopy examination. Four patients (18%), despite basement membrane abnormalities, reported no corneal symptoms suggesting recurrent erosions. In vivo confocal microscopy images showed that all patients had an abnormal epithelial basement membrane protruding into the corneal epithelium, epithelial cell abnormalities, and microcysts. No abnormalities were observed in superficial epithelial cells or the stroma.

CONCLUSION

Epithelial basement membrane dystrophy is characterized by an abnormal basement membrane protruding toward the epithelium and epithelial microcysts. In vivo confocal microscopy using the HRT II Rostock Cornea Module provides better resolution and therefore outlines distinctively in vivo microstructural characteristics of EBMD. It assists in the diagnosis of EBMD in patients suffering from recurrent erosion syndrome, particularly in patients with no corneal change visible biomicroscopically.

In vivo confocal laser scanning microscopy of the cornea in dry eye

BACKGROUND

We carried out an investigation into the morphological and quantitative corneal properties in dry eye with various underlying pathologies.

METHODS

Ten patients with aqueous tear deficiency, 8 with dysthyroid ophthalmopathy, 8 with chronic lagophthalmos and 10 normal participants were examined. Confocal microscope images were taken at the centre and at the lower and upper periphery of the cornea. Quantitative and morphological assessments of the epithelium, of the sub-basal nerves, of the stroma and the endothelium were made. The epithelial and corneal thicknesses were measured.

RESULTS

The mean superficial and intermediate epithelial cell densities in the central cornea in the patient groups were significantly lower than in normal participants (p<0.01). The peripheral epithelial thickness was smaller (p<0.01); it was smallest in the lagophthalmos group. The cornea was thinner in the patient groups (p<0.01). For sub-basal nerves, the density had decreased (p<0.05), and in lagophthalmos the number of beadlike formations had increased (p<0.001); in some patients we found irregular branching patterns.

CONCLUSIONS

Dry eye patients showed significant alterations in the cornea, presumably due to increased desquamation of the superficial cell layer. This was most pronounced at the lower periphery of the cornea in patients with exposure keratopathy.

Bilateral Infectious Ulcers Associated With Atopic Keratoconjunctivitis

PURPOSE

A case of atopic keratoconjunctivitis complicated by bilateral infectious ulcers is described.

METHODS

Both eyes underwent complete ophthalmologic examination and in vivo confocal microscopy imaging by using the Heidelberg Retina Tomograph II Rostock-cornea-module (HRT II-RCM) and were photographed.

RESULTS

Topical antibiotics and corticosteroids associated with oral antibiotics and corticosteroids were given. After 4 weeks of treatment, the corneal lesions healed completely.

CONCLUSION

Bilateral infectious ulcers with perforation are a rare and severe complication of atopic keratoconjunctivitis. HRT II-RCM in vivo confocal microscopy imaging is useful in monitoring the progression of ocular surface diseases.

Évaluation in vivo par échographie à très haute fréquence des modifications épithéliales cornéennes induites par un bêta-bloquant avec 0,01 % de chlorure de benzalkonium

PURPOSE

To assess in vivo the corneal epithelial damage caused by a topical toxic medication using a 60-MHz ultrasound device.

MATERIAL

and methods: A solution of timolol with 0.01% benzalkonium chloride (BAC) was applied twice a day in the test eyes of ten rabbits, and a BAC-free solution of timolol in the control eyes, for 56 days. We used a 60-MHz ultrasound device to evaluate the epithelial damage in BAC-exposed eyes, compared to control eyes. The clinical and ultrasound examinations were performed every week, and the histological analysis at the end of the experiment.

RESULTS

The clinical findings were conjunctival redness, corneal staining and instability of the tear film. In vivo VHF ultrasound revealed a thinning of the epithelium of test eyes (from 40.9+/-1,6 microm at D0 to 31.8+/-3.4 microm at D56; p=0.0006 for D0 vs D56), while the epithelium of control eyes remained unchanged. Ultrasound epithelial thickness was correlated with corneal staining (at D34 and D56; p=0.0025 and 0.0377, respectively) and histological epithelial pachymetry (p=0.0176 for control and 0.0505 for tested epithelium). Moreover, we report qualitative VHF ultrasound imaging of early epithelial damage.

CONCLUSION

This new device could be very useful in ocular toxicity evaluation as a reproducible and reliable tool for multicentric clinical research.

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.

Évaluation en microscopie confocale des modifications morphologiques cornéennes induites après LASIK et découpe du volet stromal par laser femtoseconde IntraLase®

PURPOSE

To assess stromal modifications occurring after IntraLase femtosecond laser for laser in situ keratomileusis (LASIK) using the Heidelberg retina tomograph II/Rostock cornea module.

MATERIAL AND METHODS

Twelve eyes from six patients were examined using the Heidelberg retina tomograph II cornea module after IntraLase femtosecond laser: ten eyes were examined at 1 week and 2 months after laser surgery, including four eyes examined at day 1, and two eyes examined at day 2. Morphological modifications of the corneal stroma, flap interface, and flap margin were evaluated at these different times and compared with the mechanical microkeratome interfaces of five patients (ten eyes), using the same technique at the same periods after the surgical intervention.

RESULTS

Evaluations at days 1 and 7 showed simultaneous depletion and activation of keratocytes on both sides of the interface. We also observed some brightly reflecting particles together with scattered, less bright dots, from day 7 and increasing after 2 months. Some clinically visible deposits at the level of the interface were observed at the periphery of the flap at day 1 and could represent cell-degradation products. With confocal microscopy, they appeared as homogeneous reflective deposits with a larger size than that of particles; they had decreased at month 2. The flap margin appeared microscopically as a very clear-cut edge, including epithelial cells, while those performed with a mechanical microkeratome appeared more like a poorly limited fibrotic scar. We also observed a secondary fibrotic reaction at month 2, adjacent to the still well-defined IntraLase flap edge.

CONCLUSION

This study showed substantial morphological similarity between the interfaces obtained with femtosecond laser and mechanical microkeratome. The discovery of brightly reflecting particles in the IntraLase interface goes against the hypothesis of the metallic origin of these deposits. The flap margin microscopically looked extremely well delimited, but seemed to provoke an adjacent secondary fibrotic reaction, both microscopically and macroscopically, greater at 2 months than after a mechanical microkeratome cut.