Intraindividual comparison between femtosecond laser-assisted and conventional cataract surgery.

PURPOSE: To compare the safety and efficacy between femtosecond laser-assisted cataract surgery using the Victus laser system and conventional cataract surgery. SETTING: Department of Ophthalmology, Kepler University Hospital, Linz, Austria. DESIGN: Prospective randomized case series. METHODS: Both eyes of patients with age-related cataract were randomized to conventional cataract surgery or femtosecond laser-assisted cataract surgery, both with intraocular lens (IOL) implantation. Postoperative follow-up was at 1 day, 1 week, 1 month, 3 months, and 6 months and comprised corrected distance visual acuity, endothelial cell density (ECD), central corneal thickness (CCT), and central retinal thickness. The main outcomes were intraoperative and postoperative complications and the effective phacoemulsification time (EPT). Intraocular lens and capsulotomy centration were evaluated using retroillumination slitlamp photography. RESULTS: The study enrolled 50 patients. No intraoperative complications occurred in either group. The ECD, CCT, and central retinal thickness were similar between the groups at all follow-up examinations (P > .05). The EPT was not statistically significantly different between the groups (P = .22). The IOL centration was similar between the groups (P = .93). CONCLUSION: Femtosecond laser-assisted and conventional cataract surgery using the mentioned system were equally safe and effective.

Computer-assisted diagnosis of monocular elevation deficiency.

Our aim is to demonstrate the benefits of using a computer model to support the clinical diagnosis of complex eye motility disorders. For diagnosis and differential diagnosis we compared the clinical data of a patient with suspected monocular elevation deficiency (MED) and the corresponding computer simulation with the simulations of rectus superior palsy, vertical Duane miswiring syndrome and two simulations of asymmetric gaze palsy. We used our biomechanical eye model SEE-KID for the computer simulations, which is partly based on ideas and concepts of the software system Orbit™ by Joel Miller. A young patient with the clinical characteristics of congenital MED, unilateral limitation of up-gaze above midline, with accompanying ptosis on the affected right side, mild head posture, chin-up position, partial binocular functions and Bell's phenomenon was examined. Pupillary situation, cover test, version and duction movements, saccadic test, Parks-Bielschowsky phenomenon and head tilt test, stereopsis test, Bagolini striated lens test and forced duction test were assessed. Up to the age of 5 years we used the prism cover test in the nine main gaze positions; later we switched to the Hess-Lancaster test for analyzing deviations. We also used our computer model for evaluating the diagnosis and for differential diagnosis of our patient. The simulation results from the SEE-KID model support the diagnosis of supranuclear MED, which can be achieved in the model by varying central innervations, contrary to the modification of muscle forces in the simulation of a rectus superior palsy. It is necessary to distinguish between supranuclear, nuclear, interstitial or peripheral lesions with regard to monocular elevation deficit. Simulations of patients with similar pathologies in a way that the simulations correspond to the patient-measured values support (beside the clinical signs) the diagnosis of supranuclear or infranuclear lesions.

Ultrastructure and retinal imaging of epiretinal membrane: a clinicopathologic correlation of trypan blue staining in epiretinal membrane surgery.

PURPOSE: The purpose of this study was to correlate the ultrastructural morphology of epiretinal tissue with optical coherence tomography and to investigate the effects of trypan blue staining on epiretinal membrane (ERM) ultrastructure and clinical outcome. METHODS: A prospective, case-comparative study. Consecutive patients were recruited and underwent vitrectomy and ERM peeling with 0.15% trypan blue; these patients were compared with a control group peeled without stain. Optical coherence tomography was performed preoperatively and at 10 days and 3 months postoperatively. Data were collected prospectively to include Snellen visual acuity and surgical ERM characteristics. Epiretinal tissue was examined using transmission electron microscopy. RESULTS: Thirty-seven patients underwent ERM surgery, and 34 had complete data, of which 18 had peeling of unstained and 16 had peeling of stained ERM. Staining resulted in a significantly greater postoperative reduction in macular thickness compared with the unstained group. There was no significant difference in the visual outcome and no ultrastructural evidence of alteration of the cleavage plane in cases in which trypan blue was used. CONCLUSION: There was no clinical or ultrastructural evidence of toxicity in peeling with trypan blue.

Ultrastructure and retinal imaging of internal limiting membrane: a clinicopathologic correlation of trypan blue stain in macular hole surgery.

PURPOSE: The purpose of this study was to correlate the ultrastructural morphology of epiretinal and retinal tissue with optical coherence tomography assessment and to investigate the effects of trypan blue staining on internal limiting membrane (ILM) tissue. METHODS: This was a prospective case-comparative study. Consecutive patients were recruited and underwent ILM peel with 0.5 mL of 0.15% trypan blue, and these were compared with a nonrandomized control group (unstained ILM). Patients underwent optical coherence tomography scanning preoperatively and postoperatively at 1.5 and 3 months. Data were collected prospectively to include Snellen visual acuity, macular hole, and operative characteristics. Internal limiting membrane was examined by transmission electron microscopy. RESULTS: Sixty-four patients underwent macular hole surgery, and complete data were available on 49 patients (17 control subjects and 32 patients who had peeling of stained ILM). Trypan blue staining significantly improved ease and completeness of ILM removal. There was no significant difference in vision, optical coherence tomography characteristics, or macular hole closure rate at 3 months between stained and unstained groups. There was no ultrastructural evidence of alteration of the plane of ILM separation in cases in which trypan blue was used. CONCLUSION: Trypan blue stain from these data seems to improve the ease and completeness of the ILM peeling (assessed clinically) and does not show any signs of toxicity.

Idiopathic macular holes: ultrastructural aspects of surgical failure.

PURPOSE: To investigate the ultrastructure of the internal limiting membrane (ILM) and epiretinal tissue in eyes with idiopathic macular holes that were not successfully closed by one operation. METHODS: A second vitrectomy with en bloc removal of the ILM and epimacular tissue was performed in 16 eyes with full-thickness macular holes after surgical failure. The specimens were processed for transmission electron microscopy. In 5 of 16 eyes, specimens of first macular hole surgery were also analyzed. RESULTS: Fibrocellular proliferation at the vitreal side of the ILM was found in all specimens from second vitrectomy. Myofibroblasts and fibroblasts were predominant. Cells were frequently observed as irregular accumulations rather than regular multilayers at the ILM. Masses of newly formed collagen were found distributed between cells and ILM. All specimens from first macular hole surgery were characterized by regular cellular layers and the presence of native vitreous collagen. CONCLUSIONS: Eyes with idiopathic macular holes that were found not to be closed early after the first vitrectomy show massive proliferation of cells and newly formed collagen irregularly distributed at the remaining ILM. After surgical intervention, ILM remnants and collagen may represent a stimulus for the early formation of tangential traction preventing successful macular hole closure.

Ultrastructure of the vitreomacular interface in full-thickness idiopathic macular holes: a consecutive analysis of 100 cases.

PURPOSE: To evaluate the ultrastructure of the vitreoretinal interface in stage III and stage IV idiopathic macular holes. DESIGN: A consecutive observational case series, laboratory investigation. METHODS: Pars plana vitrectomy with en-bloc removal of the internal limiting membrane (ILM) and epimacular tissue was performed by one surgeon in 80 eyes with stage III macular holes and in 20 eyes with stage IV macular holes. In total, 218 specimens were processed for light and transmission electron microscopy. RESULTS: Fibrocellular proliferation at the vitreal side of the ILM was found in 57 cases. Native vitreous collagen (NVC) was attached to the ILM in 36 eyes. The presence of NVC was considerably more frequent in eyes with stage IV (70%) than in eyes with stage III macular holes (26%). Mono- and multilayered cellular membranes were seen more frequently in stage IV macular holes. NVC, if present, was always associated with fibrocellular proliferation. In 39 eyes with stage III and in four eyes with stage IV macular holes, the ILM was devoid of any cells and collagen. CONCLUSIONS: Fibrocellular proliferation appears to be a secondary event instead of a primary feature in macular hole development. The severity of fibrocellular proliferation is associated with the presence of NVC. Incomplete vitreoretinal separation may contribute to the development of epimacular membranes in eyes with idiopathic macular holes. Remnants of the vitreous cortex remain more often attached to the ILM in eyes with spontaneous posterior vitreous detachment (PVD) than in eyes with surgical PVD induction.

Evaluation of the internal limiting membrane after conventional peeling during macular hole surgery.

We evaluated the histologic features of the internal limiting membrane (ILM) of the retina removed during macular hole surgery without indocyanine green staining. Our investigation focused on the presence or absence of retinal structures adherent to the retinal surface of the ILM. Because only tiny retinal cellular fragments were observed especially in ILM folds, we conclude that conventional ILM peeling can be performed safely with a cleavage plane between the retinal surface of the ILM and Müller cell endfeet.

Staining and peeling of the internal limiting membrane in the cat eye.

PURPOSE: To investigate the cat vitreomacular interface using trypan blue (TB) and indocyanine green (ICG) and to determine the validity of the cat model in terms of staining and peeling of the internal limiting membrane (ILM). METHODS: Lensectomy and vitrectomy were performed in four eyes of two cats. The ILM of two eyes was stained with TB (0.15%). ILM peeling was performed in one eye. Two eyes were stained with ICG (0.5%). One eye was illuminated for 3 min. Light and transmission electron microscopy and confocal microscopy were performed. RESULTS: Clinically, both dyes stained the cat ILM similar to human ILM. TB staining resulted in a normal ultrastructure and antigenity of the retina. ILM peeling was associated with intraretinal bleeding. There were fragments of Müller cells adherent to the retinal side of the ILM, and Müller cell endfeet were ruptured and avulsed. ICG staining of the ILM followed by illumination caused severe inner retinal damage. ICG without illumination resulted in focal ILM detachments associated with tearing of Müller cell endfeet. CONCLUSIONS: The cat can be used as a model to study the effect of TB and ICG on the central area of the cat retina, as previous results from clinical and experimental postmortem settings in human eyes were confirmed in the current study. Peeling of the ILM as a sheet as performed in human macular surgery is not feasible. Differences in the ultrastructure of the ILM and a strong adhesion of the ILM to Müller cell endfeet may account for this observation.

Epiretinal pathology of diffuse diabetic macular edema associated with vitreomacular traction.

PURPOSE: To investigate the ultrastructure of the vitreomacular interface in patients with diffuse diabetic macular edema (DDME) associated with vitreomacular traction. DESIGN: Laboratory investigation. METHODS: Fifty-five consecutive patients with DDME underwent vitrectomy with en-bloc removal of the inner limiting membrane (ILM) and epimacular tissue. Six patients were operated on both eyes. Sixty-one specimens harvested during vitrectomy were analyzed by electron microscopy. RESULTS: Preoperatively, a thickened premacular cortical vitreous was present in 47 eyes. Native vitreous collagen with single cells interspersed within the collagenous layer or a cellular monolayer were the ultrastructural features in these eyes. Twenty-three eyes showed an epimacular membrane. In eyes with obvious signs of tangential vitreomacular traction, multilayered membranes situated on a layer of native vitreous collagen were found. Fibroblasts and fibrous astrocytes were the predominant cell types; myofibroblasts and macrophages were also present. Sixty of 61 specimens showed native vitreous collagen covering the ILM. Macular edema resolved in 58 eyes and persisted in 3 eyes. No recurrent fibrocellular proliferation was observed during the follow-up period of 18 months (mean, 3 to 56 months). CONCLUSIONS: The vitreomacular interface in eyes with DDME is characterized by a layer of native vitreous collagen and a varying cellular component. Tangential vitreomacular traction is associated with multilayered membranes situated on a layer of vitreous collagen. Resolution of macular edema does not depend on the presence and removal of contractile membranes. In eyes without tangential traction, complete removal of epimacular tissue also leads to fluid resorption.

Posterior vitreous detachment induced by microplasmin.

PURPOSE: To demonstrate the efficacy of microplasmin in inducing posterior vitreous detachment (PVD) and to evaluate the human and the feline retina after treatment. METHODS: Thirteen human donor eyes were injected with 62.5, 125, or 188 micro g microplasmin. The 13 fellow eyes received balanced salt solution. Four of the microplasmin-treated eyes received an additional intravitreal gas injection. After incubation at 37 degrees C for 30 minutes, all globes were placed in 4% paraformaldehyde. Retinal specimens were processed for scanning (SEM) and transmission (TEM) electron microscopy. Five feline eyes were injected with 14.5- or 25- micro g microplasmin. Animals were killed after 1 day, 3 days, or 3 weeks, and retinal specimens were evaluated by electron and confocal microscopy. RESULTS: In all control eyes, SEM demonstrated the cortical vitreous covering the inner limiting membrane (ILM). Intravitreal injection of 125 or 188 micro g microplasmin resulted in complete PVD. After treatment with 62.5 micro g microplasmin, SEM revealed collagen fibrils covering the ILM. Additional gas injection did not change the dose necessary for PVD. In vivo in cats, 25 micro g microplasmin resulted in complete PVD after 3 days. After 3 weeks, there was complete PVD with both doses of microplasmin. The retina and the ILM were well preserved in all eyes. CONCLUSIONS: Both after death and in vivo, microplasmin induces a dose-dependent cleavage between the vitreous cortex and the ILM without morphologic alterations of the retina. In the feline eye, there is no cellular response of retinal glial cells or neurons.