Lamellar Corneal Research Articles

OCT and IVCM in corneal imaging

SummaryOptical coherence tomography (OCT) and In vivo confocal microscopy (IVCM) are two very useful imaging modalities in examination of the cornea. OCT provides non‐contact, cross sectional images with a wide angle of view, under high magnification, simulating histology but in fact are dependent on the reflectivity of tissues. Imaging through scars is poor. Clinically is it very useful in examining interfaces created by refractive surgery and lamellar corneal surgery.IVCM provides en‐face images with a restricted field of view but with a resolution range of 1.5–4 μm allowing examination at a cellular level. The different layers of the epithelium, sub‐basal plexus, Bowman's zone, stroma with keratocytes and nerves, the Descemet's membrane and endothelial cells can be clearly visualised in health and disease. Besides providing detailed morphology of the above structures it also enable visualisation of invading organisms such as acanthamoeba and fungi.Software associated with both OCT and IVCM allow measurement of dimensions of objects/area (s) of interest. OCT is more accurate in measurement of depth while IVCM enables quantification of cell size, shape and numbers. Interpretation skills require experience for both.

New histopathologic and ultrastructural findings in Reis-Bücklers corneal dystrophy caused by the Arg124Leu mutation of TGFBI gene.

BackgroundReis-Bücklers corneal dystrophy (RBCD) was consistently reported as a corneal dystrophy only affected Bowman’s layer and superficial corneal stroma, and superficial keratectomy was a recommendation surgery for treatment in literatures. The study reported new histopathological and ultrastructural findings in RBCD caused by the Arg124Leu mutation of transforming growth factor induced (TGFBI) gene in a four-generation Chinese pedigree.MethodsSubjects including eight patients and seven unaffected family members received slit-lamp biomicroscopy and photography. DNA was obtained from all subjects, and exons 4 and 11 to 14 of TGFBI gene were analyzed by polymerase chain reaction and the products were sequenced. Anterior segment optical coherence tomography (AS OCT) and in vivo confocal microscopy were conducted for ten eyes of five patients. Based on the results of AS OCT and in vivo confocal microscopy, deep anterior lamellar keratoplasty (DLKP) using cryopreserved donor cornea was applied for four eyes of four patients. Four lamellar dystrophic corneal buttons were studied by light and transmission electron microscopy, and TGFBI immunohistochemistry.ResultsEight patients had typical clinical manifestations of RBCD presenting recurrent painful corneal erosion starting in their early first decades, along with age-dependent progressive geographic corneal opacities. TGFBI sequencing revealed a heterozygous mutation, Arg124Leu in all eight patients. Anterior segment optical coherence tomography and in vivo confocal microscopy showed the dystrophic deposits involved not only in subepithelial and superficial stroma, but also in mid- or posterior stroma in four examined advanced eyes. Light microscopy showed Bowman’s layer was absent, replaced by abnormal deposits stain bright red with Masson’s trichrome. In superficial cornea, the deposits stacked and produced three to five continuous bands parallel to the corneal collagen lamellae. In mid- to posterior stroma, numerous granular or dot- like aggregates were heavily scattered, and most of them presented around the nuclei of stromal keratocytes. Transmission electron microscopy revealed the multiple electron-dense rod-shaped deposits aggregated and formed a characteristic pattern of three to five continuous bands in superficial cornea, which were similar to those seen under light microscopy. In mid- to posterior stroma, clusters of rod-shaped bodies were scattered extracellular or intracellular of the stromal keratocytes between the stromal lamellae suggesting the close relationship between mutated proteins and keratocyte.ConclusionsThe study offer evidences indicating DLKP is a viable treatment option for advanced RBCD to avoid recurrence, and the mutated TGFBIp in dystrophic corneas are of keratocytes origin.

Prognosis of clinical treatment for fungal keratitis and its influence factors

Background Fungal keratitis has poor prognosis and high blinding rate, so it is vital to identify the risk factors that affect the treating outcome and prognosis of fungal keratitis. Objective This study was to evaluate the clinical outcome of fungal keratitis and identify the affecting factors. Methods This was a series cases-observational study.A total of 267 eyes of 267 patients with fungal keratitis were included in Henan Eye Institute during January 2013 to January 2014.Eye examinations were performed including slit-lamp microscope examination, corneal smears, confocal microscopy, fungal culture and identification.Combined anti-fungal drugs were topically used in all eyes for the initial treatment then the treating regimen were selected based on the susceptibility testing.corneal lesion resection combined with conjunctival flap transplantation, lamellar corneal transplantation or penetrating corneal transplantation was performed respectively on the patients with poor curative effect after drug treatment.The clinical prognosis of the patients was graded and the affecting factors for clinical outcome were evaluated.This study protocol complied with Helsinki Declaration and was approved by Ethic Committee of Henan Eye Hospital.Written informed consent was obtained from patients or guardians. Results One hundred and eighty-five eyes were cured by anti-fungal eye drops with the effective rate of 69.29%, and the inflammation was controlled in 60 eyes who received combination procedure of anti-fungal drugs with different surgeries, while 22 eyes lost visual function because of refractory glaucoma and final evisceration.The total clinical effective rate was 91.76%.Aspergillus and Fusarium spp. appeared to be the most common pathogenic fungi by drug sensitivity test.The keratitis caused by Aspergillus had lowest cure rate among different fungi (χ2=11.350, P=0.002) and the most poor clinical prognosis (H=31.285, P=0.013). The medication curative rate was 71.8% in the patients with positive culture outcome, which was higher than 62.5% in the patients with negative culture outcome (χ2=8.75, P<0.01). A significant difference was found in the medication curative rate and prognosis between the patients with ≥2 kinds of sensitive anti-fungal drugs and the patients with <2 kinds of sensitive anti-fungal drugs (77.5% versus 52.3%, χ2=9.63, P<0.01; H=24.281, P=0.021). Size of infiltration area, with or without hypopyon, number of sensitive drugs, and pathogenic fungi were significantly correlated with clinical outcome(all at P<0.05). Conclusions In vitro susceptibility testing can guide clinical drug treatment of fungal keratitis.Infiltration area >16 mm2, hypopyon >2 mm, resistance to those drugs in vitro and infection of Fusarium.spp or Aspergillus.spp are predictors of a poor outcome. Key words: Eye infections, fungal/therapy; Keratitis, fungal, Treatment outcome; Risk factors; Human

Optical coherence tomography characteristics of different types of big bubbles seen in deep anterior lamellar keratoplasty by the big bubble technique.

PurposeTo define optical coherence tomography (OCT) characteristics of type-1, type-2, and mixed big bubbles (BB) seen in deep anterior lamellar keratoplasty.MethodsHuman sclero-corneal discs were obtained from UK (30) and Canada (16) eye banks. Air was injected into corneal stroma until a BB formed. UK samples were fixed in formalin before scanning with Fourier-domain (FD-OCT). One pair of each type of BB was scanned fresh. All BB obtained from Canada were scanned fresh with time-domain (TD-OCT). For each OCT machine used, type-1 BB from which Descemets membrane (DM) was partially peeled, were also scanned. The morphological characteristics of the scans were studied.ResultsFD-OCT of the posterior wall of type-1 (Dua's layer (DL) with DM) and type-2 BB (DM alone) both revealed a double-contour hyper-reflective curvilinear image with a hypo-reflective zone in between. The anterior line of type-2 BB was thinner than that seen with type-1 BB. In mixed BB, FD-OCT showed two separate curvilinear images. The anterior image was a single hyper-reflective line (DL), whereas the posterior image, representing the posterior wall of type-2 BB (DM) was made of two hyper-reflective lines with a dark space in between. TD-OCT images were similar with less defined component lines, but the entire extent of the BB could be visualised.ConclusionOn OCT examination the DM and DL present distinct features, which can help identify type-1, type-2, and mixed BB. These characteristics will help corneal surgeons interpret intraoperative OCT during lamellar corneal surgery.

Three-dimensional mapping of the orientation of collagen corneal lamellae in healthy and keratoconic human corneas using SHG microscopy.

Keratoconus is an eye disorder that causes the cornea to take an abnormal conical shape, thus impairing its refractive functions and causing blindness. The late diagnosis of keratoconus is among the principal reasons for corneal surgical transplantation. This pathology is characterized by a reduced corneal stiffness in the region immediately below Bowman's membrane, probably due to a different lamellar organization, as suggested by previous studies. Here, the lamellar organization in this corneal region is characterized in three dimensions by means of second-harmonic generation (SHG) microscopy. In particular, a method based on a three-dimensional correlation analysis allows to probe the orientation of sutural lamellae close to the Bowman's membrane, finding statistical differences between healthy and keratoconic samples. This method is demonstrated also in combination with an epi-detection scheme, paving the way for a potential clinical ophthalmic application of SHG microscopy for the early diagnosis of keratoconus. SHG image acquired with sagittal optical sectioning (A) of a healthy cornea and (B) of a keratoconic cornea. Scale bars: 30μm.

Clinical observation on the corneal endothelium transplantation for the treatment of corneal decompensation

Objective To investigate the clinical effect of corneal endothelium transplantation for corneal decompensation. Methods Six eyes of 6 patients of secondary corneal decompensation after cataract surgery were enrolled. They had undergone corneal endothelium transplantation. The 13~14 mm diameter of deep lamellar corneal endothelial implant was separated with cornea knife, and it was transplanted into receptor anterior chamber. Results The six eyes were followed up for over 6 months. The cornea was transparent in all cases, and the endothelial implant attached well. The visual acuity was improved from preoperative FC-0.05 to 0.12-0.3 six months after surgery. The average corneal endothelial cell density increased significantly from ≤656/mm2 preoperatively to 1889-2456/mm2 postopevatively. Conclusion The corneal endothelium transplantation is an effective method for the treatment of corneal decompensation. Key words: Corneal endothelium transplantation; Corneal decompensation

Immunosuppression after corneal transplantation : Clinical standards and novel approaches

Corticosteroid eye drops are the mainstay of immunosuppressive therapy after routine lamellar and perforating corneal transplantation. Commonly occurring side effects are cataract formation and increased intraocular pressure. Alternative immunosuppressive agents could allow the dosage of glucocorticoids to be reduced. The antibiotic azithromycin is a candidate drug that showed anti-inflammatory properties in cell cultures and animal models and has positive effects on transplant rejection.

Polarimetric Interferometry for Assessment of Corneal Stromal Lamellae Orientation.

To analyze corneal stromal lamellae orientation in normal subjects and patients with various corneal conditions using a polarimetric interferometer. Thirty-two healthy control subjects (59 eyes) and 16 patients (22 eyes) with corneal conditions or postkeratoplasty were included in the study. All patients were imaged using the interferometer and slit lamp photography. The interferometer produces an orthogonal cross-like image of stromal lamellae by illuminating the cornea in phase-light polarization angle. Corneal haze was graded on a scale from 0 to 4. Interferometer cross-like images were graded on a scale from 0 to 5 by a masked observer. Keratometry, corneal central pachymetry, and optical densitometry were obtained with Scheimpflug corneal tomography. The cross-like image was observed in 31 of 32 healthy control subjects (58 of 59 eyes) and in 13 of 16 patients (19 of 22 eyes). The image was not detectable in 3 patients, 1 with total corneal neovascularization and scarring, 1 with central leukoma, and 1 with failed deep lamellar keratoplasty. Corneal haze was the main factor obscuring the cross-like image (P < 0.05). Clarity of the images was influenced by older age, steeper keratometry, higher pachymetry, and optical density (P < 0.05). There was no correlation between the orientation of the keratometric axes and the orientation of the 2 arms of the cross-like image (P > 0.05). Corneal stromal lamellae orientation can be efficiently assessed and displayed as a cross-like image by the polarimetric interferometer. Stromal lamellae orientation imaging may have potential implications in corneal diagnostics and surgery.

The curative effect of injecting human umbilical cord mesenchymal stem cells into corneal stroma for lamellar corneal laceration

Objective To investigate the effect of injecting the umbilical cord mesenchymal stem cells into corneal stroma after lamellar corneal laceration. Methods Twenty healthy New Zealand white rabbits were selected and the left eyes were taken for experimental eyes. The corneal tunnel knife was used to make horizontal tunnel incision at 12 and 6 o'clock respectively 2 mm away from corneal limbus but didn't penetrate the cornea. And at 12 o'clock the umbilical cord mesenchymal stem cells were injected into corneal stroma and at 6 o'clock the saline solution was injected. The corneal incision scar and the corresponding degree of corneal opacity were observed at 1, 3, 7, 14, 21 and 28 days respectively after the treatment. Results At 1, 3 and 7 days after the treatment, there were not statistically significant differences between the two groups, but at 14, 21 and 28 days at 6 o'clock the corneal opacity were more obvious than that at 12 o'clock between the two groups and the P values were 0.001, 0.002 and 0.011 (P<0.05). At 21 days after the treatment, the scar was the most obvious at 6 o'clock. Conclusion Injection of umbilical cord mesenchymal stem cells into corneal stroma after corneal laceration can reduce the scar formation. Key words: Cornea; Lamellar corneal laceration; Human umbilical cord mesenchymal stem cells; Corneal stroma injection; Scar

An experimental study of mesenchymal stem cells in tissue engineering scaffolds implanted in rabbit corneal lamellae to increase keratoprosthesis biointegration

To complete a preliminary evaluation of the feasibility of implanting the complex of mouse bone marrow mesenchymal stem cells (BMSC) and a tissue engineering scaffold into rabbit corneal lamellae, based on which a solution may be proposed to consolidate the keratoprosthesis and the recipient surface, and to reduce the risk of complications. This experimental study was composed of two parts. (1) In vitro: some mouse BMSC were marked with red fluorescent proteins (RFP) and integrated with a decellularized pig articular cartilage extracellular matrix (ECM) scaffold. The cell survival was observed under a fluorescence microscope at 4 and 8 weeks. The cell distribution was examined by toluidine blue staining. The pore structure and the cell adhesion were observed under a scanning electron microscope. (2) in vivo: the complex of mouse BMSC and a decellularized scaffold was implanted into the lamellar cornea of 8 rabbit eyes with the fellow eyes as the controls. The eyes were sampled for observation using HE staining under a light microscope at 2, 4 and 8 weeks, respectively. The cell survival was examined under a fluorescence microscope, and the intracorneal cell survival at 8 weeks was observed using in vivo imaging. The conditions of ocular anterior segment of all the experimental animals were recorded. (1) Under the scanning electron microscope, the ECM scaffolds showed satisfactory porosity required for the adhesion and growth of cells and tissues, and the cell distribution over the cell-scaffold complex can be observed by toluidine blue staining. (2) Under the immunofluorescence microscope, cell proliferation was observed in vitro and in the interlamellar space (the maximum observation time was 8 weeks) after the RFP-marked mouse BMSC were integrated in vitro with ECM scaffolds. (3) Under the light microscope (HE staining), the stromal cells were detected to increase at each timepoint. A small number of monocytes and some mouse BMSC were observed in the superficial layer of corneal stroma, with sparsely and orderly arranged collagenous fibers and no neovascularization. All the epithelial cells appeared as mononuclear, columnar and undamaged, and the shape of ECM scaffolds, which were fused with the collagens, became unclear. (4) By in vivo imaging, it was found that the mouse BMSC survived for 8 weeks after being integrated with scaffolds and implanted into the interlamellar space of rabbit cornea. (5) After the implantation of cell-scaffold complex, severe postoperative inflammatory reactions, obvious conjunctival congestion and neovascularization were not observed. The corneal tissues surrounding the recipient area were transparent. One week later, mild inflammatory reactions were barely observed, and the cornea was transparent enough to observe the scaffold in the stromal layers. Four weeks later, the scaffolds became thinner. Eight weeks later, the scaffolds became extremely thin with normal vascular system in the corneal limbus. The ECM scaffold is a solid and biocompatible carrier for the growth and proliferation of BMSC. The mouse BMSC can grow and proliferate in the microenvironment of the interlamellar space of cornea.

A new OCT sign of invasive squamous cell carcinoma of the cornea

Case reportA case is reported of an unusual progressive corneal opacification and neovascularization caused by a squamous cell carcinoma (SCC) of the cornea. A patient with a white stromal infiltrate, consistent with herpetic stromal keratitis, showed a very particular image in optical coherence tomography (OCT), resembling a “tongue of lava” sliding between corneal lamellae. Histopathological analysis confirmed the diagnosis of SCC. DiscussionTo our knowledge this is the first report in the literature of this peculiar image with OCT. Squamous cell carcinoma is an extremely rare cause of progressive corneal opacification and neovascularization, and a delayed diagnosis may lead to unsuccessful treatment and loss of the eyeball.

Role of real-time intraoperative optical coherence tomography in lamellar corneal surgeries

Real-time intraoperative optical coherence tomography (iOCT) integrated into the operating microscope can be used for optimizing the outcome of lamellar corneal surgeries. Surgical technique can be modified intraoperatively by its use, and surgical endpoint can be achieved in the operating room itself. We have successfully utilized the use of iOCT for refining the endpoint of surgical procedures such as deep anterior lamellar keratoplasty, descemet stripping automated endothelial keratoplasty, descemet membrane endothelial keratoplasty, and superficial anterior lamellar keratoplasty. Continuous iOCT imaging is a new technique that allows an accurate estimation of the depth of dissection, aiding in the modification of surgical planning.

Role of real-time intraoperative optical coherence tomography in lamellar corneal surgeries

Role of real-time intraoperative optical coherence tomography in lamellar corneal surgeries

LASIK interface primary complications

Laser in situ Keratomileusis (LASIK) is one of the most accepted techniques in refractive surgery today. Its predictability, reproducibility, safety and low incidence of side effects justify the wide diffusion of this technique. This is a laser surgical procedure which purpose consists in the modification of corneal structure, allowing a shift of the focal point of the eye. Thus, it is possible to correct refractive errors such as myopia, astigmatism and small degrees of hyperopia. The LASIK technique creates a corneal flap interface with the use of a microkeratome or femtosecond laser. Then, excimer laser is applied on the stroma bed followed by repositioning of the flap, creating an interface between the anterior and posterior corneal lamella. Despite the numerous advantages there are patologies that originate from primary complications of the interface which can caused confusion during diagnosis because they have similarities in their clinical presentation. The aim of this work is to define, characterize and compare those entities with the intention of making the diagnosis easier so that there is appropriate conduct. As result, this study presents recommendations for the management of each kind of interface disease through investigation by medical history and physical examination, in order to allow differential diagnosis between the main primary entities of the LASIK procedure interface.

Carcinoma de células escamosas en la córnea: un nuevo signo de invasión corneal en la tomografía de coherencia óptica

Case reportA case is reported of an unusual progressive corneal opacification and neovascularization caused by a squamous cell carcinoma (SCC) of the cornea. A patient with a white stromal infiltrate, consistent with herpetic stromal keratitis, showed a very particular image in optical coherence tomography (OCT), resembling a «tongue of lava» sliding between corneal lamellae. Histopathological analysis confirmed the diagnosis of SCC. DiscussionTo our knowledge this is the first report in the literature of this peculiar image with OCT. Squamous Cell Carcinoma is an extremely rare cause of progressive corneal opacification and neovascularization, and a delayed diagnosis may lead to unsuccessful treatment and loss of the eyeball.

How Much Progress Has Been Made in Corneal Transplantation?

To assess the benefits of component lamellar corneal surgery, we investigated the surgical outcomes of deep anterior lamellar keratoplasty (DALK) for keratoconus and Descemet stripping automated endothelial keratoplasty (DSAEK) for laser iridotomy-induced bullous keratopathy (LI-BK). The results were compared with the surgical outcomes of penetrating keratoplasty (PKP). Seventy-nine eyes with keratoconus treated with DALK and 81 eyes with LI-BK treated with DSAEK were studied, and the graft clarity rate, best spectacle-corrected visual acuity, endothelial cell density (ECD), and surgical complications were compared with 273 eyes with keratoconus and 98 eyes with LI-BK all treated with PKP. Keratoconus eyes showed excellent visual outcomes with DALK and PKP, but graft survival was higher for PKP (100%, 98.9%, and 96.3% vs. 98.6%, 90.6%, and 86.1%, at 1, 3, and 5 years after surgery, respectively; P < 0.0001). There were no significant differences in the ECD up to 1 year after surgery. Greater ECD decline was observed for PKP at 3 and 5 years after surgery. Descemet membrane microperforation was observed in 49 eyes treated with DALK. Postoperative complications in eyes treated with PKP were increased incidence of immunological rejection and secondary glaucoma compared with eyes treated with DALK. LI-BK graft survival rates were excellent in both groups (DSAEK: 89.6% and 86.1%; PKP: 100% and 98.6%, 1- and 2-year rates, respectively; P = 0.17). Best spectacle-corrected visual acuity was better in the DSAEK group, and ECD showed a higher rate of decrease with DSAEK than with PKP. DALK and DSAEK considerably improved surgical outcomes in eyes with keratoconus and those with LI-BK, respectively. However, several key areas require further work, including development of safe surgical methods in DALK and prevention of early postoperative ECD loss in DSAEK.

Utility of peripheral lamelar corneal graft in PUK with corneal perforation treatment

PurposePeripheral ulcerative keratitis (PUK) is a destructive inflammation of the limbal corneal stroma with oval morphology. It is characterized by a sectorial affection with corneal thinning, usually associated with an epithelial defect, cell infiltration and progressive lysis of the stroma, which can progress to corneal perforation.We present a case of a 88 years old woman who came to our hospital with epifora and foreign body sensation in the left eye. It was observed perforated marginal corneal ulceration in inferonasal quadrant with iris incarceration. She was treated with therapeutic contact lens and topical antibiotics and was programmed for surgery. In order to maintain the corneal integrity and due to the dimensions of the perforation, we decided to employ a lamellar corneal grafting because the use of tissue adhesives or amniotic membrane coating would be insufficient. This prevents the elimination of healthy cornea and keep better the anatomy. In the same surgery the graft was covered with amniotic membrane patch securing it with biological glue and coated with therapeutic contact lens.MethodsThe lamellar corneal grafting was obtained by manually cutting one of the corneoscleral edges of a donor cornea, in which the central corneal button was drilled and used for another patient in a penetrating keratoplasty the same day of surgery.ResultsThe postoperative time coursed with no complications and showed good integration of corneal graft, through images of the anterior segment and AS‐OCT.ConclusionsLamellar corneal graft seems to be a good treatment option for maintaining the tectonic integrity in perforated patients due to peripheral ulcerative keratitis.

Contribution of Optical Coherence Tomography (OCT) with real‐time OCT of the Femtosecond laser, and per operative OCT of the microscope in deep anterior lamellar keratoplasty (DALK) for keratoconus: a new technique

PurposeDeep anterior lamellar keratoplasty (DALK) is a treatment of choice for keratoconus. We evaluate the contribution of a new technique associating femtosecond laser with real‐time OCT, and per‐operative OCT on the microscope, in DALK surgeries for keratoconus.MethodsAfter training on artificial anterior chambers of corneal grafts to evaluate the reproducibility of cuts, pre‐cuts of human anterior corneal lamellae during DALK of keratoconus were realized using the femtosecond laser (Victus, Bausch and Lomb) with real‐time OCT and a curved applanation's surface. The depth was caculated around 60% of the thinnest pachymetry. Surgeries were realized using the per‐operative OCT with the Rescan system of the microscope (Lumera 700, Zeiss).ResultsCurved applanation and visualization with real‐time OCT of the cuts’ depth enabled the realization of reproducible lamellar cuts on 200 µ thick corneas, without modifying the laser‐cornea interface neither using masking agents. Femtosecond laser cuts allowed the big‐bubble formation on 10/10 ex‐vivo corneas. In human surgeries, real‐time OCT visualization allowed controlling non‐penetrating cuts, and the curved applanation limited folds formation on the residual stroma. Each surgical step was controlled by per‐operative OCT, with visibility of tissues’ structure and thickness, and instruments in cross section. The Anwar‐air dissection technique permitted the “big‐bubble” formation in 7/7 case, clearly visible on OCT, with only 1 or 2 injections of air. Residual posterior stroma was resected realizing pre‐descemetic lamellar grafts.ConclusionsThis new technique, femtosecond laser associated with per‐operative OCT, appears to be safe, effective, reproducible and time‐saving in DALK surgeries, facilitating the “big‐bubble” formation. It may be proposed for the management of keratoconus and other indications.

Contribution of Optical Coherence Tomography (OCT) with real‐time OCT of the Femtosecond laser, and per operative OCT of the microscope in deep anterior lamellar keratoplasty (DALK) for keratoconus: a new technique

PurposeDeep anterior lamellar keratoplasty (DALK) is a treatment of choice for keratoconus. We evaluate the contribution of a new technique associating femtosecond laser with real‐time OCT, and per‐operative OCT on the microscope, in DALK surgeries for keratoconus.MethodsAfter training on artificial anterior chambers of corneal grafts to evaluate the reproducibility of cuts, pre‐cuts of human anterior corneal lamellae during DALK of keratoconus were realized using the femtosecond laser (Victus, Bausch and Lomb) with real‐time OCT and a curved applanation's surface. The depth was caculated around 60% of the thinnest pachymetry. Surgeries were realized using the per‐operative OCT with the Rescan system of the microscope (Lumera 700, Zeiss).ResultsCurved applanation and visualization with real‐time OCT of the cuts’ depth enabled the realization of reproducible lamellar cuts on 200 µ thick corneas, without modifying the laser‐cornea interface neither using masking agents. Femtosecond laser cuts allowed the big‐bubble formation on 10/10 ex‐vivo corneas. In human surgeries, real‐time OCT visualization allowed controlling non‐penetrating cuts, and the curved applanation limited folds formation on the residual stroma. Each surgical step was controlled by per‐operative OCT, with visibility of tissues’ structure and thickness, and instruments in cross section. The Anwar‐air dissection technique permitted the “big‐bubble” formation in 7/7 case, clearly visible on OCT, with only 1 or 2 injections of air. Residual posterior stroma was resected realizing pre‐descemetic lamellar grafts.ConclusionsThis new technique, femtosecond laser associated with per‐operative OCT, appears to be safe, effective, reproducible and time‐saving in DALK surgeries, facilitating the “big‐bubble” formation. It may be proposed for the management of keratoconus and other indications.

Comparison of Superior Rectus and Peripheral Lamellar Corneal Traction Suture during Trabeculectomy

Purpose: To compare the efficacy and safety of two different traction suture (superior rectus traction suture and peripheral lamellar corneal traction suture) in patients undergoing trabeculectomy.Methods: This retrospective trial compared outcomes of 385 eyes that underwent trabeculectomy with superior rectus traction suture (SRTS group; 206 eyes; 53.3%) and peripheral lamellar corneal traction suture (CTS group; 179 eyes; 46.7%). Qualified surgical success is defined as an intraocular pressure (IOP) between 6 and 21 mm Hg with or without topical anti-glaucoma medication.Results: After a follow-up of 24 months, the difference of IOP was significant (p = 0.042). The mean number of anti-glaucoma medications was 3.5 ± 0.6 and 3.5 ± 0.5 preoperatively (p = 1.000), whereas 0.18 ± 0.32 and 0.10 ± 0.39 at 24 months (p = 0.028). The 24-month qualified surgical success rates were 88.3% and 94.4% for both groups (p = 0.035; log-rank test). The difference between the two groups in regard to maximal bleb area is statistically significant (p = 0.011), with CTS group exhibiting more diffuse bleb area. The difference between the two groups in regard to the vascularity at the central and peripheral part of bleb is statistically significant (p = 0.019; p = 0.023, respectively). Encysted blebs was seen in 27 (13.1%) eyes in SRTS group and in 12 (6.7%) eyes in CTS group (p = 0.041).Conclusion: The use of superior rectus traction suture is significantly associated with a lower success rate than corneal traction suture, suggesting that surgeons should use a corneal fixation suture if at all possible.