Use of the Three-dimensional Viewing System and Microscope Tilting to Extend the Peripheral Retinal View.

PURPOSE: To describe and evaluate the effectiveness of the microscope and lens tilting technique associated with the three-dimensional viewing system for improving the peripheral retinal view in noncontact lens vitreoretinal surgeries. METHODS: Prospective, single-center, single-surgeon, consecutive case series of 25 patients undergoing vitrectomy for macular surgeries with three-dimensional visualization system. At the end of each surgery, the microscope and the noncontact lens were rotated by 20° in a direction opposite to the rotation of the eye to extend the peripheral visual field. RESULTS: Microscope and lens tilting technique extended the edge of the peripheral viewing field relative to its position with the microscope untilted, by 1.72 mm (±0.37) for the superior retina and 1.93 mm (±0.42) for the inferior retina (P < 0.0001). The ora serrata was visualized in 33% and 0% of cases for the superior retina and 91% and 36% of cases for the inferior retina, in tilted and nontilted microscope positions, respectively (P < 0.01). CONCLUSION: Microscope and lens tilting could be useful to extend the peripheral visual field of view in retinal surgery. The three-dimensional system allowed to maintain surgeon comfort and posture during surgery.

Use of Digital Methods to Optimize Visualization during Surgical Gonioscopy.

Purpose: The aim of this study was to evaluate the efficacy of digital visualization for enhancing the visualization of iridocorneal structures during surgical gonioscopy. Methods: This was a prospective, single-center study on a series of 26 cases of trabecular stent implantation performed by the same surgeon. Images were recorded during surgical gonioscopy, and before stent implantation, with standard colors and with the optimization of various settings, principally color saturation and temperature and the use of the cyan color filter. Subjective analyses were performed by two glaucoma surgeons, and objective contrast measurements were made on iridocorneal structure images. Results: The surgeons evaluating the images considered the optimized digital settings to produce enhanced tissue visibility for both trabecular meshwork pigmentation and Schlemm's canal in more than 65% of cases. The mean difference in the standard deviation of the pixel intensity values was 37.87 (±4.61) for the optimized filter images and 32.37 (±3.51) for the standard-color images (p < 0.001). The use of a cyan filter provided a good level of contrast for the visualization of trabecular meshwork pigmentation. Increasing the color temperature highlighted the red appearance of Schlemm's canal. Conclusions: We report here the utility of optimized digital settings including the cyan filter and a warmer color for enhancing the visualization of iridocorneal structures during surgical gonioscopy. These settings could be used in surgical practice to enhance the visualization of the trabecular meshwork and Schlemm's canal during minimally invasive glaucoma surgery.

Nestin contributes to laser choroidal and retinal neovascularization.

Purpose: Choroidal and retinal neovascularization plays an essential role in various ocular diseases. In this study, we examined the role of nestin in this process. Nestin is an intermediate filament protein known to play several roles, including as a marker of neural progenitor and proliferating endothelial cells. Methods: We used Brown Norway rats, in which choroidal and retinal neovascularization was induced using intraocular laser impacts. The role of nestin was examined using angiography, western blot from the second to the 14th day after laser impacts, and intraocular injection of nestin siRNA. The localization of the protein was specified by co-immunoreactivity with glial fibrillary protein (GFAP), glutamine synthetase (GS), and von Willebrand factor (vWF). Results: In the control retina, nestin was found principally in glial structures in the ganglion cell layer, as confirmed by nestin/GFAP immunolabeling. Two days after the laser impacts, the nestin expression extended to numerous radial processes at the site of the impacts. With Bruch's membrane ruptured, these processes penetrated into the choroid. Nestin immunolabeling remained high from the third to the seventh day but appeared reduced on the 14th day. The nature of these processes was not clearly defined, but co-immunolabeling with GFAP suggested that they were principally in activated Müller cells from the third day after the laser impacts. However, the co-immunoreactivity of nestin and GS, a marker of mature functional Müller cells, could be observable only from the seventh day. Nestin was also observed in some vascular cells, as demonstrated by the co-immunoreactivity of the protein with vWF in the choroid and retina. As observed on angiography, the numbers of choroidal and retinal blood vessels were significantly increased (principally on the seventh day) after the laser impacts. An intraocular injection of nestin siRNAs led to a significant decrease in the number of blood vessels. Conclusions: Our results confirmed the presence of nestin in glial (e.g., astrocytes), reactive Müller, and endothelial cells. They demonstrated their critical involvement in a rat model of retinal and choroidal neovascularization experimentally induced using ocular laser impacts.

Use of Black-and-White Digital Filters to Optimize Visualization in Cataract Surgery.

PURPOSE: To evaluate the effect of a black-and-white (BW) filter on the optimization of visualization at each stage of cataract surgery. METHODS: Prospective, single-center, single-surgeon, consecutive case series of 40 patients undergoing cataract surgery with BW filter. Surgical images and videos were recorded with and without the BW filter at each stage of cataract surgery. Contrast measurements of surgical images and subjective analysis of video sequences were performed. RESULTS: The surgeons assessed the BW filter to optimize the tissue visibility of capsulorhexis contours, hydrodissection fluid wave perception, the contrast of instruments through a nucleus during phaco-chop, and subincisional cortex contrast through the corneal edema. Despite the higher contrasts' value obtained with BW filter images during nucleus removal, posterior capsular polishing and viscous removal, the surgeons subjectively reported no significant advantage of using a BW filter. Standard color images were found to be better for localizing the limbal area during incision and for nucleus sculpture to assess groove depth. CONCLUSIONS: In conclusion, we describe here the potential indications for BW filter use at particular stages in cataract surgery. A BW filter could be used, with caution, in cases of poor visualization.

Facilitating Role of the 3D Viewing System in Tilted Microscope Positions for Cataract Surgery in Patients Unable to Lie Flat.

PURPOSE: To assess the utility of the 3D viewing system in tilted microscope positions for the performance of cataract surgery in challenging positions, for patients with difficulty remaining supine. METHODS: Prospective, single-center, single-surgeon, consecutive case series of patients undergoing surgery in an inclined position. RESULTS: 21 eyes of 15 patients who had undergone surgery at inclined positions at angles of 20° to 80°, with a mean angle of 47.62°. Surgeon comfort was considered to be globally good. The surgeon rated red reflex perception and the impression of depth as good and stable in all cases. The operating time was slightly longer for patients inclined at angles of more than 50°. On the first day after surgery, BSCVA was 20/25 or better in all cases. No ocular complications occurred in any of the interventions. CONCLUSIONS: Due to the ocular-free design of the 3D system, the surgical procedure and the positioning of the surgeon remained almost identical to that for patients undergoing surgery in a supine position, maintaining the safety of the standard surgical approach.

Early corneal pachymetry maps after cataract surgery and influence of 3D digital visualization system in minimizing corneal oedema.

PURPOSE: To describe the early topography of corneal swelling occurring after cataract surgery and to evaluate the impact of the three-dimensional (3D) digital visualization system in minimizing corneal oedema. METHODS: Prospective observational, single-centre, consecutive case series of 134 patients undergoing cataract surgery performed by the same surgeon, with either 3D or conventional visualization systems. Eyes were assigned to two groups based on their anterior chamber depth (group ACD ≤3 mm and group ACD >3 mm). Optical coherence tomography was performed to evaluate postoperative corneal swelling. RESULTS: Three corneal swelling profiles were identified on the first postoperative day type 1, limited corneal oedema near peripheral corneal incisions; type 2, dome-shaped corneal swelling spreading from the principal corneal incision and reaching the paracentral cornea; type 3, continuous oedema spreading from the principal incision to central cornea, with a generalized oedema predominating in the upper part of the cornea. On the first day after surgery, in group ACD ≤3 mm, visual acuity was significantly better in patients undergoing surgery with 3D visualization (0.023 vs 0.072 logMar, p = 0.014) with reduced central corneal thickening 17.3 µm (±3.2) in comparison with conventional visualization 44.0 µm (±9.3) (p = 0.0082). In group ACD >3 mm, no significant association was found between the use of the 3D system and pachymetry changes and early visual rehabilitation. On day 21 after surgery, no significant differences in corneal pachymetry values were observed between the two surgical approaches in both groups. CONCLUSIONS: We describe early postoperative corneal map profiles providing insight into the pathogenesis of postoperative corneal swelling and possible prevention strategies. By improving visualization of the narrow surgical space in patients with shallow anterior chambers, the 3D system could help to minimize postoperative corneal oedema.

CFH exerts anti-oxidant effects on retinal pigment epithelial cells independently from protecting against membrane attack complex.

Age Related Macular Degeneration (AMD) is the first cause of social blindness in people aged over 65 leading to atrophy of retinal pigment epithelial cells (RPE), photoreceptors and choroids, eventually associated with choroidal neovascularization. Accumulation of undigested cellular debris within RPE cells or under the RPE (Drusen), oxidative stress and inflammatory mediators contribute to the RPE cell death. The major risk to develop AMD is the Y402H polymorphism of complement factor H (CFH). CFH interacting with oxidized phospholipids on the RPE membrane modulates the functions of these cells, but the exact role of CFH in RPE cell death and survival remain poorly understood. The aim of this study was to analyze the potential protective mechanism of CFH on RPE cells submitted to oxidative stress. Upon exposure to oxidized lipids 4-HNE (4-hydroxy-2-nonenal) derived from photoreceptors, both the human RPE cell line ARPE-19 and RPE cells derived from human induced pluripotent stem cells were protected from death only in the presence of the full length human recombinant CFH in the culture medium. This protective effect was independent from the membrane attack complex (MAC) formation. CFH maintained RPE cells tight junctions' structure and regulated the caspase dependent apoptosis process. These results demonstrated the CFH anti-oxidative stress functions independently of its capacity to inhibit MAC formation.

In vivo imaging of palisades of Vogt in dry eye versus normal subjects using en-face spectral-domain optical coherence tomography.

PURPOSE: To evaluate a possible clinical application of spectral-domain optical coherence tomography (SD-OCT) using en-face module for the imaging of the corneoscleral limbus in normal subjects and dry eye patients. PATIENTS AND METHODS: Seventy-six subjects were included in this study. Seventy eyes of 35 consecutive patients with dry eye disease and 82 eyes of 41 healthy control subjects were investigated. All subjects were examined with the Avanti RTVue® anterior segment OCT. En-face OCT images of the corneoscleral limbus were acquired in four quadrants (inferior, superior, nasal and temporal) and then were analyzed semi-quantitatively according to whether or not palisades of Vogt (POV) were visible. En-face OCT images were then compared to in vivo confocal microscopy (IVCM) in eleven eyes of 7 healthy and dry eye patients. RESULTS: En-face SD-OCT showed POV as a radially oriented network, located in superficial corneoscleral limbus, with a good correlation with IVCM features. It provided an easy and reproducible identification of POV without any special preparation or any direct contact, with a grading scale from 0 (no visualization) to 3 (high visualization). The POV were found predominantly in superior (P<0.001) and inferior (P<0.001) quadrants when compared to the nasal and temporal quadrants for all subjects examined. The visibility score decreased with age (P<0.001) and was lower in dry eye patients (P<0.01). In addition, the score decreased in accordance with the severity of dry eye disease (P<0.001). CONCLUSION: En-face SD-OCT is a non-contact imaging technique that can be used to evaluate the POV, thus providing valuable information about differences in the limbal anatomy of dry eye patients as compared to healthy patients.

Amyloid Precursor-Like Protein 2 deletion-induced retinal synaptopathy related to congenital stationary night blindness: structural, functional and molecular characteristics.

BACKGROUND: Amyloid precursor protein knockout mice (APP-KO) have impaired differentiation of amacrine and horizontal cells. APP is part of a gene family and its paralogue amyloid precursor-like protein 2 (APLP2) has both shared as well as distinct expression patterns to APP, including in the retina. Given the impact of APP in the retina we investigated how APLP2 expression affected the retina using APLP2 knockout mice (APLP2-KO). RESULTS: Using histology, morphometric analysis with noninvasive imaging technique and electron microscopy, we showed that APLP2-KO retina displayed abnormal formation of the outer synaptic layer, accompanied with greatly impaired photoreceptor ribbon synapses in adults. Moreover, APLP2-KO displayed a significant decease in ON-bipolar, rod bipolar and type 2 OFF-cone bipolar cells (36, 21 and 63 %, respectively). Reduction of the number of bipolar cells was accompanied with disrupted dendrites, reduced expression of metabotropic glutamate receptor 6 at the dendritic tips and alteration of axon terminals in the OFF laminae of the inner plexiform layer. In contrast, the APP-KO photoreceptor ribbon synapses and bipolar cells were intact. The APLP2-KO retina displayed numerous phenotypic similarities with the congenital stationary night blindness, a non-progressive retinal degeneration disease characterized by the loss of night vision. The pathological phenotypes in the APLP2-KO mouse correlated to altered transcription of genes involved in pre- and postsynatic structure/function, including CACNA1F, GRM6, TRMP1 and Gα0, and a normal scotopic a-wave electroretinogram amplitude, markedly reduced scotopic electroretinogram b-wave and modestly reduced photopic cone response. This confirmed the impaired function of the photoreceptor ribbon synapses and retinal bipolar cells, as is also observed in congenital stationary night blindness. Since congenital stationary night blindness present at birth, we extended our analysis to retinal differentiation and showed impaired differentiation of different bipolar cell subtypes and an altered temporal sequence of development from OFF to ON laminae in the inner plexiform layer. This was associated with the altered expression patterns of bipolar cell generation and differentiation factors, including MATH3, CHX10, VSX1 and OTX2. CONCLUSIONS: These findings demonstrate that APLP2 couples retina development and synaptic genes and present the first evidence that APLP2 expression may be linked to synaptic disease.

Evaluation of Blebs After Filtering Surgery With En-Face Anterior-Segment Optical Coherence Tomography: A Pilot Study.

PURPOSE: To compare characteristics of functioning blebs (FBs) and nonfunctioning blebs (NFBs) with en-face spectral-domain optical coherence tomography (OCT). METHODS: We evaluated 41 blebs of 38 patients after a first-time trabeculectomy. Eyes were classified into 2 groups: FBs (22 eyes) and NFBs (19 eyes). En-face OCT images were analyzed semiquantitatively for the density of intraepithelial microcysts (0 to 3), internal fluid-filled cavity (0 to 3), and bleb vascularization (0 to 2). Presence of conjunctival fibrosis and visualization of the scleral flap were also analyzed. RESULTS: FBs showed significantly more intraepithelial microcysts than did NFBs: the mean grading of microcyst density was 1.86 for FBs and 0.11 for NFBs (P<0.0001). None of the FBs were rated 0 and none of the NFBs were rated 2 or 3 for the density of intraepithelial microcysts. NFBs presented more conjunctival fibrosis than FBs (63% vs. 32%, P<0.05). There was no significant difference between FBs and NFBs for bleb vascularization, visualization of the scleral flap, and presence of subepithelial fluid-filled cavities. There was a direct correlation between postoperative intraocular pressure and intraepithelial microcyst density (r=-0.7655, P<0.0001). The long-term administration of preserved eyedrops before surgery was associated with fewer intraepithelial microcysts (r=-0.5436; P=0.0006). CONCLUSIONS: FBs were associated with a higher number of intraepithelial microcysts evaluated with en-face OCT. A higher density of microcysts was associated with a lower intraocular pressure and a shorter duration of preserved topical treatment before surgery. En-face OCT provides a simple, noninvasive, and reproducible method to analyze blebs after filtering surgery.

Symmetry in early response to intravitreal ranibizumab in bilateral diabetic macular oedema.

PURPOSE: To study the symmetry in response to bilateral diabetic macular oedema (DME) treated with bilateral intravitreal injections of ranibizumab (IVR). METHODS: The charts of 36 eyes of 18 patients treated with a loading dose of three monthly IVR in both eyes were retrospectively reviewed. Favourable anatomical response was defined as a decrease by more than 10% in baseline central macular thickness (CMT), and favourable functional response was defined as an increase in visual acuity (VA) ≥5 letters. A symmetric response was defined as a similar anatomical and/or functional response in the first (FE) and second (SE) treated eyes. RESULTS: The VA improved significantly after ranibizumab treatment in both eyes (p < 0.01). A statistically significant positive correlation was found for the functional response to ranibizumab between the FE and the SE (R(2)  = 0.26, p = 0.03). The mean CMT decreased significantly in both eyes (p < 0.01). A strong positive correlation was observed between the anatomical response to ranibizumab in the FE and the SE (R(2)  = 0.37, p = 0.01). Symmetric favourable anatomical and functional responses were observed in 13 patients (72%). In two additional patients, an asymmetric functional response was observed despite a decrease in retinal thickness in both eyes. CONCLUSION: Symmetric anatomical and functional responses were observed in 72% of patients with DME after three initial IVR in each eye. This finding could be of clinical interest in the decision to treat the fellow eye, in a disease where a bilateral involvement is frequent.

Targeting iron-mediated retinal degeneration by local delivery of transferrin.

Iron is essential for retinal function but contributes to oxidative stress-mediated degeneration. Iron retinal homeostasis is highly regulated and transferrin (Tf), a potent iron chelator, is endogenously secreted by retinal cells. In this study, therapeutic potential of a local Tf delivery was evaluated in animal models of retinal degeneration. After intravitreal injection, Tf spread rapidly within the retina and accumulated in photoreceptors and retinal pigment epithelium, before reaching the blood circulation. Tf injected in the vitreous prior and, to a lesser extent, after light-induced retinal degeneration, efficiently protected the retina histology and function. We found an association between Tf treatment and the modulation of iron homeostasis resulting in a decrease of iron content and oxidative stress marker. The immunomodulation function of Tf could be seen through a reduction in macrophage/microglial activation as well as modulated inflammation responses. In a mouse model of hemochromatosis, Tf had the capacity to clear abnormal iron accumulation from retinas. And in the slow P23H rat model of retinal degeneration, a sustained release of Tf in the vitreous via non-viral gene therapy efficently slowed-down the photoreceptors death and preserved their function. These results clearly demonstrate the synergistic neuroprotective roles of Tf against retinal degeneration and allow identify Tf as an innovative and not toxic therapy for retinal diseases associated with oxidative stress.

Anatomic Predictive Factors of Acute Corneal Hydrops in Keratoconus: An Optical Coherence Tomography Study.

PURPOSE: To define the optical coherence tomography (OCT) corneal changes predisposing to acute corneal hydrops among patients with advanced keratoconus. DESIGN: Retrospective cohort study. PARTICIPANTS: A total of 191 advanced keratoconic eyes from 191 patients with advanced keratoconus cases were studied. METHODS: Data collected from patients with advanced keratoconus cases were studied during a minimum period of 24 months of follow-up. High-resolution Fourier-domain corneal OCT (5 µm of axial resolution) and corneal topography were performed every 4 months during the follow-up. Several anatomic features at the keratoconus cone were analyzed with OCT, including epithelial and stromal thicknesses, the aspect of Bowman's layer, the presence of Vogt's striae, and stromal opacities. A comparative analysis between anatomic corneal features in eyes that developed corneal hydrops and those that did not develop this complication during the follow-up was performed. MAIN OUTCOME MEASURES: Evaluation of anatomic corneal changes at risk of developing a corneal hydrops on the basis of OCT findings. RESULTS: Eleven cases of corneal hydrops (5.8%) occurred in our series during a mean follow-up of 30 months (24-36 months). All of these patients were male and younger (23.7±5.9 years) than patients with no acute keratoconus (32.7±11.3 years). Increased epithelial thickening with stromal thinning at the conus and the presence of anterior hyperreflectives at the Bowman's layer level were significantly associated with corneal hydrops, whereas the presence of corneal scarring was a preventive factor. At the healing stage, a pan-stromal scar occurs, with a significant stromal thickening and cornea flattening. CONCLUSIONS: Increased epithelial thickening, stromal thinning at the keratoconus cone, anterior hyperreflectives at the Bowman's layer level, and the absence of stromal scarring are associated with a high risk of developing corneal hydrops. These aspects should be taken into account by the clinician in the evaluation of keratoconus eyes and in the planning of corneal keratoplasty.

A new CRB1 rat mutation links Müller glial cells to retinal telangiectasia.

We have identified and characterized a spontaneous Brown Norway from Janvier rat strain (BN-J) presenting a progressive retinal degeneration associated with early retinal telangiectasia, neuronal alterations, and loss of retinal Müller glial cells resembling human macular telangiectasia type 2 (MacTel 2), which is a retinal disease of unknown cause. Genetic analyses showed that the BN-J phenotype results from an autosomal recessive indel novel mutation in the Crb1 gene, causing dislocalization of the protein from the retinal Müller glia (RMG)/photoreceptor cell junction. The transcriptomic analyses of primary RMG cultures allowed identification of the dysregulated pathways in BN-J rats compared with wild-type BN rats. Among those pathways, TGF-ß and Kit Receptor Signaling, MAPK Cascade, Growth Factors and Inflammatory Pathways, G-Protein Signaling Pathways, Regulation of Actin Cytoskeleton, and Cardiovascular Signaling were found. Potential molecular targets linking RMG/photoreceptor interaction with the development of retinal telangiectasia are identified. This model can help us to better understand the physiopathologic mechanisms of MacTel 2 and other retinal diseases associated with telangiectasia.

Corneal epithelial thickness mapping using Fourier-domain optical coherence tomography for detection of form fruste keratoconus.

PURPOSE: To determine whether optical coherence tomography (OCT) epithelial mapping can improve the detection of form fruste keratoconus. SETTING: French National Eye Hospital, Paris 6 Pierre & Marie Curie University, Paris, France. DESIGN: Retrospective comparative study. METHODS: Eyes with normal corneas, form fruste keratoconus, moderate keratoconus, or severe keratoconus were assessed using Fourier-domain OCT (RTVue 5.5), scanning-slit corneal topography (Orbscan IIz), and rotating Scheimpflug camera (Pentacam Comprehensive Eye Scanner). Several parameters provided by the software or derived from elevation maps, OCT pachymetric maps, and OCT epithelium parameters were evaluated and compared between the 4 groups. RESULTS: The study involved 145 eyes. There were no significant differences in the keratometry (K) value, inferior-superior value, keratoconus index, central K index, and topographic keratoconus classification indices between the form fruste keratoconus group and the control group (P > .05). Form fruste keratoconic corneas had less epithelial thickness in the thinnest corneal zone than normal corneas, and greater epithelial thickness in the thinnest corneal zone than keratoconic corneas (P < .005). The epithelial thickness in the thinnest corneal zone in form fruste corneas was located inferiorly (P < .005) and corresponded with the zone of minimum epithelial thickness and maximum posterior elevation (P < .005). The receiver operating characteristic curve analysis showed good overall predictive accuracy of the epithelial thickness in the thinnest corneal zone, with a 52 µm threshold value for discriminating form fruste keratoconic corneas from normal corneas. CONCLUSIONS: The epithelial thickness in the thinnest corneal zone and its location provided by the OCT epithelial mapping might be useful for the early diagnosis of form fruste keratoconus. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.

Fourier-domain optical coherence tomography imaging in corneal epithelial basement membrane dystrophy: a structural analysis.

PURPOSE: To investigate the features of corneal epithelial basement membrane dystrophy using spectral-domain optical coherence tomography (SD OCT) and to examine the reliability of SD OCT in distinguishing epithelial basement membrane dystrophy from the normal cornea. DESIGN: Diagnostic test study. METHODS: Forty-five individuals with epithelial basement membrane dystrophy and 45 age- and sex-matched controls with normal corneas were examined, and SD OCT scans of their corneas were performed. In vivo confocal microscopy was performed to confirm or rule out the diagnosis of epithelial basement membrane dystrophy. The structural corneal changes occurring in eyes with epithelial basement membrane dystrophy based on SD OCT findings were described. RESULTS: Epithelial abnormalities were observed in 86 of 87 eyes with epithelial basement membrane dystrophy (45 patients) on SD OCT scans. The 2 main features were the presence of an irregular and thickened epithelial basement membrane duplicating or insinuating into the corneal epithelium layer, or both, and the presence of hyperreflective dots. In some cases, we detected hyporeflective spaces between the corneal epithelial layer and the Bowman layer similar to a corneal epithelial detachment. This corneal epithelial detachment sometimes was associated with a cleavage with a stair-step appearance within the corneal epithelial layer. We found a perfect correlation between in vivo confocal microscopy and SD OCT findings in the diagnosis of epithelial basement membrane dystrophy (κ = 0.98). CONCLUSIONS: SD OCT provides an accurate assessment of the structural changes occurring in eyes with epithelial basement membrane dystrophy. These changes, visible on SD OCT scans, are easily detectable and permit an accurate diagnosis, especially in patients with no biomicroscopically visible corneal changes.

VITRECTOMY WITH INTERNAL LIMITING MEMBRANE PEELING FOR TRACTIONAL AND NONTRACTIONAL DIABETIC MACULAR EDEMA: Long-term Results of a Comparative Study.

PURPOSE: To compare the long-term outcomes of vitreomacular surgery in eyes with nontractional diabetic macular edema (DME) with those from eyes with tractional DME. METHODS: Retrospective comparative study from 55 consecutive patients (73 eyes). Twenty eyes were operated on for tractional DME and 53 eyes for nontractional DME unresponsive to laser photocoagulation or triamcinolone intravitreal injections. The best-corrected visual acuity, the central macular thickness, and the surgical complications were analyzed. RESULTS: The mean follow-up duration was 5.3 ± 2.4 years for the group with traction and 4.4 ± 1.7 years for the group without traction (P = 0.13). At 3 years, the mean logarithm of the minimum angle of resolution best-corrected visual acuity had improved significantly from 0.78 to 0.58 for the group without traction and from 0.75 to 0.45 for the group with traction (P < 0.001). At the final visit, there was no significant difference between the 2 groups in regard to visual or central macular thickness improvement (P = 0.447 and P = 0.742, respectively). The incidence of surgical complications was not significant between the two groups. The preoperative best-corrected visual acuity was the only predictive factor for the final best-corrected visual acuity. CONCLUSION: The results of vitrectomy were not different in terms of anatomical and visual outcomes and surgical complications between eyes without tractional DME and eyes with tractional DME.

Optical coherence tomography and confocal microscopy following three different protocols of corneal collagen-crosslinking in keratoconus.

PURPOSE: We compared the efficacy and early morphological changes in the cornea following conventional (C-CXL), transepithelial by iontophoresis (I-CXL), and accelerated (A-CXL) collagen cross-linking in keratoconus. METHODS: A total of 45 eyes of 45 patients with progressive keratoconus who underwent corneal collagen crosslinking (CXL) was divided into three groups: C-CXL (n = 15), A-CXL (n = 15), and I-CXL (n = 15). Patients were examined before surgery and at 1-, 3-, and 6-month intervals following surgery. Density of corneal sub-basal nerves, anterior and posterior keratocytes, corneal endothelium, demarcation line depth, and maximal simulated keratometry values (Kmax) were all assessed. RESULTS: Compared to preoperative values, the mean corneal sub-basal nerve and anterior stromal keratocyte densities were significantly lower at 6 months in the C-CXL and A-CXL groups (P < 0.001), whereas they returned to preoperative values in the I-CXL group (P = 0.083 and P = 0.909, respectively). The corneal demarcation line was visible 1 month after surgery in 93% of cases (mean depth, 302.8 ± 74.6 µm) in the C-CXL group, 87.5% (mean depth, 184. 2 ± 38.9 µm) in the A-CXL group, and 47.7% (mean depth, 212 ± 36.5 µm) in the I-CXL group (P = 0.006). There were no significant differences between confocal microscopy and optical coherence tomography measurements of the corneal demarcation line depth (P > 0.05). The Kmax, corneal central thickness, and BSCVA remained stable during the whole study period. CONCLUSIONS: Iontophoresis was associated with weaker damage of corneal sub-basal nerves and anterior keratocytes compared to conventional procedures, but the demarcation line was present in less than 50% of cases and was more superficial than with the traditional procedure.

En-face optical coherence tomography as a novel tool for exploring the ocular surface: a pilot comparative study to conventional B-scans and in vivo confocal microscopy.

PURPOSE: To explore the potential of spectral-domain optical coherence tomography (SD-OCT) using the en-face technology for the imaging of ocular surface diseases and to correlate the findings with in vivo confocal microscopy (IVCM) images. PATIENTS AND METHODS: 113 eyes of 75 subjects with various ocular surface diseases were investigated with the RTVue(®) anterior-segment en face OCT. En face OCT images were compared to B-scan OCT and IVCM images. RESULTS: Patients with corneal dystrophies, corneal deposits, keratitis, pterygium, conjunctivochalasis, or ocular surface squamous neoplasia and patients who underwent lamellar corneal surgeries were included. En-face OCT images showed ocular surface tissue changes that were not discernible using conventional B-scan OCT. Nevertheless, there was a good correlation with IVCM analysis. Compared with IVCM, the major advantages of en-face OCT included easy operation and rapid image acquisition, with minimal operator experience required. In addition, the non-contact method avoided patient discomfort and external pressure on the globe, which was especially useful in patients with corneal dystrophies, ulcers, or corneal abscesses. Although the resolution of en-face OCT was lower than that of IVCM, it allowed useful overall visualization of corneal lesions due to the larger areas analyzed. CONCLUSION: En-face SD-OCT is a novel, valuable tool to assess a wide variety of ocular surface diseases. It can provide additional information and new insight into different ocular surface conditions with no corneal contact.

New combined technique of deep intrastromal arcuate keratotomy overlayed by LASIK flap for treatment of high astigmatism.

PURPOSE: The aim of this study was to describe a novel technique combining deep intrastromal arcuate keratotomy and superficial lamellar keratotomy followed by excimer photoablation for the management of high naturally occurring or postkeratoplasty astigmatism. METHODS: In this retrospective case series, the first step was deep intrastromal arcuate keratotomy and superficial lamellar keratotomy performed at 100-µm depth by femtosecond laser. Manual incisions were made for flap elevation. The second step, after 1 month, consisted of reopening the flap and using an excimer laser to correct residual ametropia. RESULTS: Nine eyes series were studied. The mean preoperative refractive cylinder correction was 6.11 ± 2.54 diopters (D). The mean postoperative refractive cylinder correction was 2.85 ± 1.31 D. The mean correction index was 1.07 ± 0.28 D. The mean best-corrected visual acuity improved from 20/40 to 20/22 after the 2 steps. The median follow-up was 11 (range, 9-17) months. No complications were observed and postoperative outcome was satisfactory. CONCLUSIONS: Permitting correction of a broader range of high astigmatism with good accuracy, this combined approach minimizes excision of corneal stromal tissue and postoperative complications.