Ophthalmic Technologies Research Articles

Femtosecond laser in refractive and cataract surgeries.

In the past few years, 9 unique laser platforms have been brought to the market. As femtosecond (FS) laser-assisted ophthalmic surgery potentially improves patient safety and visual outcomes, this new technology indeed provides ophthalmologists a reliable new option. But this new technology also poses a range of new clinical and financial challenges for surgeons. We provide an overview of the evolution of FS laser technology for use in refractive and cataract surgeries. This review describes the available laser platforms and mainly focuses on discussing the development of ophthalmic surgery technologies.

Are nanotechnology and robotics alternatives for therapeutic and theragnostic ophthalmic applications technologies for eye care services

Objective: To identify new technological advances in biotechnology, nanotechnology and robotics and their application in diagnosis and therapeutics for visual health. Methodology: The systematic review was made in Journal of Engineering, Journal of Biomedical Nanotechnology, NIH Public Access, Investigative Ophthalmology & Visual Science, Intechweb open access journal and books, among others for a total review of 43 articles and 6 books. The databases used were: NLM Catalogue, (NCBI), Scirus, CiteSeer and open access (Intechopen, Hindawi) with the advances in nanotechnology, artificial vision and robotics applied to visual health. Results: Retina implants, ocular memristors, ocular electrodes and chips, digital cameras and smart phone applications for low vision patients are some of the new alternatives in technology for the diagnosis based on biotechnology and nanotechnology and on the several years of job of interdisciplinary and multidisciplinary researchers of different fields to make innovation useful for visual impairment, ocular microbiology and molecular immunodiagnostics. The FDA recently approved the retina implants and this opened a new field to allow converting light signals into electrical signals. On the other hand, in the field of pharmacology, ocular nano-carrier molecules for sustained release of drugs and other devices to vitrectomies are some of the significant health advance studies for the future in visual health. Additionally, in the field of contact lenses and artificial corneas: biopolymers for biosensors have been developed for early detection of keratoconus and systemic diseases. Conclusions: Nanotechnology, biotechnology, robotics and bio-molecular biology are emerging and convergent sciences that when applied to visual sciences will be helpful for the patients, and are an increase in papers on innovation of this field, involving a multidisciplinary team requiring new divulgation in the role and performance of the visual health professionals of the future. To know and divulgate these new technologies is important for continued joint efforts around global education, and to create a database with new keywords, in order to know who and where these innovations are improving around the world, to planning researcher mobility and to include these new valuable technologies in the curriculum of visual health and get the patient safe.

Integrated Photoacoustic Ophthalmoscopy and Spectral-domain Optical Coherence Tomography

Both the clinical diagnosis and fundamental investigation of major ocular diseases greatly benefit from various non-invasive ophthalmic imaging technologies. Existing retinal imaging modalities, such as fundus photography1, confocal scanning laser ophthalmoscopy (cSLO)2, and optical coherence tomography (OCT)3, have significant contributions in monitoring disease onsets and progressions, and developing new therapeutic strategies. However, they predominantly rely on the back-reflected photons from the retina. As a consequence, the optical absorption properties of the retina, which are usually strongly associated with retinal pathophysiology status, are inaccessible by the traditional imaging technologies. Photoacoustic ophthalmoscopy (PAOM) is an emerging retinal imaging modality that permits the detection of the optical absorption contrasts in the eye with a high sensitivity4-7 . In PAOM nanosecond laser pulses are delivered through the pupil and scanned across the posterior eye to induce photoacoustic (PA) signals, which are detected by an unfocused ultrasonic transducer attached to the eyelid. Because of the strong optical absorption of hemoglobin and melanin, PAOM is capable of non-invasively imaging the retinal and choroidal vasculatures, and the retinal pigment epithelium (RPE) melanin at high contrasts 6,7. More importantly, based on the well-developed spectroscopic photoacoustic imaging5,8 , PAOM has the potential to map the hemoglobin oxygen saturation in retinal vessels, which can be critical in studying the physiology and pathology of several blinding diseases 9 such as diabetic retinopathy and neovascular age-related macular degeneration. Moreover, being the only existing optical-absorption-based ophthalmic imaging modality, PAOM can be integrated with well-established clinical ophthalmic imaging techniques to achieve more comprehensive anatomic and functional evaluations of the eye based on multiple optical contrasts6,10 . In this work, we integrate PAOM and spectral-domain OCT (SD-OCT) for simultaneously in vivo retinal imaging of rat, where both optical absorption and scattering properties of the retina are revealed. The system configuration, system alignment and imaging acquisition are presented.

Integrated Photoacoustic Ophthalmoscopy and Spectral-domain Optical Coherence Tomography

Both the clinical diagnosis and fundamental investigation of major ocular diseases greatly benefit from various non-invasive ophthalmic imaging technologies. Existing retinal imaging modalities, such as fundus photography, confocal scanning laser ophthalmoscopy (cSLO), and optical coherence tomography (OCT), have significant contributions in monitoring disease onsets and progressions, and developing new therapeutic strategies. However, they predominantly rely on the back-reflected photons from the retina. As a consequence, the optical absorption properties of the retina, which are usually strongly associated with retinal pathophysiology status, are inaccessible by the traditional imaging technologies. Photoacoustic ophthalmoscopy (PAOM) is an emerging retinal imaging modality that permits the detection of the optical absorption contrasts in the eye with a high sensitivity. In PAOM nanosecond laser pulses are delivered through the pupil and scanned across the posterior eye to induce photoacoustic (PA) signals, which are detected by an unfocused ultrasonic transducer attached to the eyelid. Because of the strong optical absorption of hemoglobin and melanin, PAOM is capable of non-invasively imaging the retinal and choroidal vasculatures, and the retinal pigment epithelium (RPE) melanin at high contrasts. More importantly, based on the well-developed spectroscopic photoacoustic imaging, PAOM has the potential to map the hemoglobin oxygen saturation in retinal vessels, which can be critical in studying the physiology and pathology of several blinding diseases such as diabetic retinopathy and neovascular age-related macular degeneration. Moreover, being the only existing optical-absorption-based ophthalmic imaging modality, PAOM can be integrated with well-established clinical ophthalmic imaging techniques to achieve more comprehensive anatomic and functional evaluations of the eye based on multiple optical contrasts. In this work, we integrate PAOM and spectral-domain OCT (SD-OCT) for simultaneously in vivo retinal imaging of rat, where both optical absorption and scattering properties of the retina are revealed. The system configuration, system alignment and imaging acquisition are presented.

Current and Potential Therapies for Ocular Neovascular Diseases

therapy approved to treat neovascular AMD. It is a two step procedure involving the intravenous administration of the drug, and subsequent activation by a non-thermal laser beam. This “cool” laser treatment produces a chemical reaction that selectively destroys abnormal blood vessels. However it is only for those patients who have new blood vessel growth under the retina in a well defined, distinctive pattern known as “predominantly classic.” Visudyne was developed by Novartis. Laser photocoagulation is another classic treatment for choroidal NV. The procedure uses laser light to destroy or seal off new blood vessels to prevent leakage. A major drawback of PDT and laser photocoagulation is that recurrent NV post-treatment is extremely common, since that these therapies don’t eliminate the angiogenic stumili. Laser photocoagulation produces many small retinal scars, which cause blind spots in the patient’s visual field. Multiple treatments are always needed. FDA approved the Implantable Miniature Telescope (IMT) in 2010, developed by VisionCare Ophthalmic Technologies. The intraocular implant magnifies images onto the retina to improve central vision damaged by advanced AMD or Stargardt’s maculat dystrophy. This device is only for patients at least 75 years old with severe to profound vision impairment. Among these treatments, VEGF antagonisms have provided major benefits to patients. Recent progress unveiling the molecular pathogenesis of the diseases has lead to potential new drug therapy. Other key angiogenesis mediators, such as Platelet Derived Growth Factor B (PDGF-B) and NF-κB-responsive mediator Vascular Cell Adhesion Molecule-1 (VCAM-1) [9], can provide potential therapy to combat worsening of NV diseases. Nonetheless, monthly injections of VEGF inhibitors into the eyes can cause harmful side effects, and some patients didn’t have an optimal response. A promising potential new treatment is gene-transfer of antiangiogenic factors through viral vectors, which has the potential to provide long-term suppression of NV and excessive vascular leakage [10].

Spectral domain OCT versus time domain OCT in the evaluation of macular features related to wet age-related macular degeneration

BackgroundThe aim of this study was to compare the agreement between spectral domain optical coherence tomography (SD OCT) and time domain stratus OCT (TD OCT) in evaluating macular morphology alterations in wet age-related macular degeneration (AMD).MethodsThis retrospective study was performed on 77 eyes of 77 patients with primary or recurring subfoveal choroidal neovascularization secondary to AMD. All patients underwent OCT examination using Zeiss Stratus OCT 3 (Carl Zeiss Meditec Inc, Dublin, CA) and Opko OTI Spectral SLO/OCT (Ophthalmic Technologies Inc, Toronto, Canada). In all radial line scans, the presence of intraretinal edema (IRE), serous pigment epithelium detachment (sPED), neurosensory serous retinal detachment (NSRD), epiretinal membrane (EM), inner limiting membrane thickening (ILMT), and hard exudates (HE) were evaluated. The degree of matching was quantified by Kappa measure of agreement.ResultsThe percentage distribution of TD OCT findings versus SD OCT findings was: IRE 36.3% versus 77.9%, sPED 57.1% versus 85.7%, NSRD 38.9% versus 53.2%, EM 10.5% versus 26.3%, ILMT 3.8% versus 32.4%, and HE 6.4% versus 54.5%. The agreement was as follows: sPED: kappa value 0.15; NSRD: kappa value 0.61; IRE: kappa value 0.18; EM: kappa value 0.41; ILMT: kappa value 0.02; HE: kappa value 0.06.ConclusionThe agreement in the evaluation of macular lesions between the two techniques is poor and depends on the lesion considered. SD OCT allows better detection of the alterations typically related to choroidal neovascularization such as IRE, PED, ILM thickening, and HE. Consequently its use should be strongly considered in patients with wet AMD.

Improving quality of life in patients with end-stage age-related macular degeneration: focus on miniature ocular implants

Low vision devices in the past have been mainly extraocular. There are now four new devices in different stages of development and implementation that are currently available. Three of them, the Implantable Miniature Telescope (IMT, VisionCare Ophthalmic Technologies, Saratoga, CA), Intraocular Lens for Visually Impaired People (IOL-VIP, IOL-VIP System, Soleko, Pontecorvo, Italy), and Lipschitz Mirror Implant (LMI, Optolight Vision Technology, Herzlia, Israel) are implanted into the anterior segment while the Argus II (Second Sight Medical Products, Sylmar, CA) is implanted into the posterior segment. The goal of these devices is to increase the patient quality of life which has been measured by Visual Functioning Questionnaire (VFQ) scales. The IMT is the only device that has been shown to increase the VFQ score by seven points at 6 months compared to baseline. It is the only FDA-approved device in the US while the Argus has been approved in Europe. Each of these prosthetics has potential benefits for patients.

Adaptive optics for studying visual function: a comprehensive review.

Compared to most ophthalmic technologies, adaptive optics, or AO, is relatively young. The first working systems were presented in 1997 and, owing in part to its complexity, the development of AO systems has been relatively slow. Nevertheless, AO for vision science is coming of age and the scope of applications continues to increase. Applications of AO can be broadly split along two lines; for retinal imaging and for testing visual function. This review will focus on the applications of adaptive optics for testing visual function. Since this represents only a subset of the field of AO for ophthalmoscopy, it is possible to cite virtually every paper that has been published in the field to date. As such, this is a comprehensive review whose intent is to get all readers up to speed on the state of the art. More importantly, perhaps, this review will focus on the types of science that can be accomplished with AO with a view to future applications. The reference list alone is informative, since the reader will quickly discover that the community that is using AO for vision science is rather small. Looking at the dates for the cited papers, the reader will also discover that the field is rapidly expanding.

Spectral Domain Optical Coherence Tomography Findings of Retinal Macroaneurysm.

A 47-year-old healthy male presented to the ophthalmology clinic with complaint of dry eyes. Examination revealed visual acuity 20/20 in both eyes (OU). Anterior segment examination was normal. Fundus examination and fluorescein angiogram findings were consistent with a non-ruptured macroaneurysm. Spectral domain (SD) optical coherence tomography (OCT) (Ophthalmic Technologies, Ontario, Canada) demonstrated a large 215 mu lumen with inferior hyperreflectivity at the area of hemorrhage. There was focal thickening of the retina to encompass the macroaneurysm but no associated retinal edema. The higher resolution afforded by SD OCT may allow more accurate measurement of the size of the aneurysm, making it possible to evaluate prognostically relevant characteristics of the aneurysm such as hemorrhage in the vessel wall or thrombus in the lumen. This may also allow us to possibly intervene earlier in high-risk cases. SD OCT may be of value in management of retinal macroaneurysm.

Spectral domain optical coherence tomography findings of acute branch retinal artery occlusion from calcific embolus

An 82-year-old female presented with sudden painless decrease in vision in the right eye after awakening. She could see the “superior half” of her vision from the right eye only. On examination, best-corrected vision was 20/300 in the right eye and 20/30 in the left eye. The fundus in the right eye revealed recent superotemporal branch retinal artery occlusion (BRAO) with calcified plaque at the disc. Spectral domain optical coherence tomography (OCT) (OTI Ophthalmic Technologies, Inc.), revealed hyperreflectivity and increased thickness of the inner retinal layers of the superior compared to the inferior retina. Imaging at the optic disc revealed the blocked artery containing a highly reflective material. The high reflectivity of the material and underlying optical shadowing could be characterized as calcific emboli.

201 Validité de l’analyse de l’épaisseur de la couche des fibres optiques dans le glaucome

Objective The purpose of this retrospective study is to check on the added value that the OCT can bring to the patients who have or are suspected to have open angle glaucoma. Methods Chart of patients who had a retinal nerve fiber analysis (RNFL) study using the OCT of the Ophthalmic Technologies Inc. (OTI, Toronto, Canada) were reviewed. The Eyes included in the study were those who had available on their chart beside the RNFL analysis a full history et eye examination, intraocular pressure measurement (by non contact et by applanation), a central pachymetry (CCT), a gonioscopy, a cup/disc evaluation (90 D et red free Photos) and a visual field. Correlation between RNFL analysis, CCT, C/D evaluation, et visual fields was done. Results A total of around 250 eye files (∼120 patients) had complete data. More than 20% of the eyes had repeated examinations spaced by a year. There was a moderate correlation between the visual field defects et the RNFL analysis. The evaluation of the C/D done by the 90 D lens et the measured area on the OCT image also showed a moderate correlation. The correlation between the IOP, the CCT et the RNFL seems to be mild to moderate (N.B. all the statistical analysis is still underway). RNFL analysis was a useful ancillary test in the eyes where it was initially difficult to decide whether to treat the patients or not. Many patients showed abnormal thin RNFL inferotemporal quadrant despite normal visual field examination. Only a minority of patients could not be studied by OCT because of pathologic myopia or media aberrations. Conclusion OCT in glaucoma showed good repeatability in the eyes that had more than one analysis. It was also useful in the follow up of patients. RNFL is affected earlier in the disease than the visual field et could be helpful for early glaucoma suspects. Larger series are needed to confirm that. Further study is needed to confirm whether the OCT image can be counted upon for the C/D evaluation. RNFL analysis seems to be a good ancillary test that helps in deciding when to treat patients suspected to have COAG.

Exploring Ocular Aberrations with a Schematic Human Eye Model

Advances in ophthalmic technologies now offer both the measurement and reduction of ocular aberrations by surgically or otherwise honing refraction in the anterior eye. Ocular aberrations, however, are known to change with a multitude of factors, including field position, accommodation level, and age. Thus, although static correction of aberrations provides some vision improvement, this may be less than expected. In this article, we use an aspheric, variable-focus, age-dependent, gradient index schematic eye to investigate where ocular aberrations arise in the eye and how these change with field position, accommodation, and age. Optical ray tracing was carried out using optical design software ZEMAX, and Seidel aberration analysis was performed with custom written software in MATLAB. Our modeling is consistent with clinical findings that certain corneal aberrations almost balance those arising from the lens. Our calculations also support the general notion that, by optical sculpting, corneal aberrations can be adjusted to completely balance out those of the lens. This can effectively eliminate the eye's total monochromatic aberrations, but for only one retinal image point at a time. Centered on this point of minimal aberration is a region (the isoplanatic patch) within which the aberrations produce a point spread smaller than some tolerable limit. Also, using available evidence in the literature concerning changes in critical ocular parameters with age and accommodation, our modeling results parallel established clinical findings, and additionally indicate that the major source of aberration change can be attributed to the gradient index distribution in the lens.

Optic nerve sheath diameter, intracranial pressure and acute mountain sickness on Mount Everest: a longitudinal cohort study

Objective:To investigate the association of optic nerve sheath diameter (ONSD), as a correlate of intracranial pressure (ICP), with acute mountain sickness (AMS).Design:Longitudinal cohort study of mountaineers from sea level to...

Anterior Segment Imaging: Optical Coherence Tomography Versus Ultrasound Biomicroscopy

To determine the clinical indications of anterior segment optical coherence tomography (AS-OCT) and ultrasound biomicroscopy in anterior segment imaging. Eighty patients were evaluated using AS-OCT and ultrasound biomicroscopy. AS-OCT was ideal for detailed imaging of structures from the surface of the eye to the iris plane. Ultrasound biomicroscopy was ideal for imaging structures from the surface of the eye to the anterior vitreous. AS-OCT is indicated for imaging the conjunctiva, sclera, cornea, and iris, screening the angle, and visualizing subconjunctival, corneal, and anterior chamber implants. Coronal imaging, unique to AC Cornea OCT (Ophthalmic Technologies Inc., Toronto, Ontario, Canada), graphically defines structures viewed on cross-sectional OCT. Ultrasound biomicroscopy is indicated for imaging the conjunctiva, sclera, iris, lens, and ciliary body, for tumor measurements, for light-and-dark tests in glaucoma, and for viewing subconjunctival, anterior chamber, posterior chamber, and pars plana implants.

Posterior Iris Fixation of the Iris-Claw Intraocular Lens Implantation through a Scleral Tunnel Incision

To evaluate the technique, efficacy, and safety of posterior iris fixation of iris-claw intraocular lens (IOLs) implantation through a scleral tunnel incision for aphakia correction. Noncomparative, interventional case series. A secondary posterior iris fixation of the Artisan iris-claw IOL (Ophthec BV, Groningen, The Netherlands) was implanted for aphakia correction in the authors' clinical practice. Uncorrected visual acuity, best spectacle-corrected visual acuity (BSCVA), astigmatism, manifest refraction, lens position, pigment dispersion, and intraocular pressure (IOP) were evaluated in 32 consecutive eyes of 32 patients. BSCVA was 20/40 or better in 28 eyes (87.50%) during the mean follow-up time (nine months). Mean postoperative spherical equivalent was -0.70 diopters (D; standard deviation [SD], 0.47 D) at six months after surgery. Mean prediction error was -0.13 D (SD, 0.28 D), and mean absolute prediction error was 0.26 D (SD, 0.15 D). Preoperative mean astigmatism was -1.08 D (SD, 0.55 D; range, 0.0 to -2.0 D). At six months after surgery, mean astigmatism was -2.1 D (SD, 0.81 D; range, -0.75 to -3.75 D). There was no significant postoperative IOP increase. Lens position, evaluated by Oculus Pentacam (Pentacam 70700: Oculus, Wetzlar, Germany) and ultrasound biomicroscopy [UBM] (Ophthalmic Technologies Inc, Toronto, Ontario, Canada), was parallel to the iris plane. Posterior iris fixation of the iris-claw IOL implantation through a scleral tunnel incision is a safe procedure and an effective option for aphakic eyes without capsule support.

Multimodal imaging in macular diagnostics: combined OCT-SLO improves therapeutical monitoring

Digital imaging methods are a centrepiece for diagnosis and management of macular disease. A recently developed imaging device is composed of simultaneous confocal scanning laser ophthalmoscopy (SLO) and optical coherence tomography (OCT). By means of clinical samples the benefit of this technique concerning diagnostic and therapeutic follow-up will be assessed. The combined OCT-SLO-System (Ophthalmic Technologies Inc., Toronto, Canada) allows for confocal en-face fundus imaging and high resolution OCT scanning at the same time. OCT images are obtained from transversal line scans. One light source and the identical scanning rate yield a pixel-to-pixel correspondence of images. Three-dimensional thickness maps are derived from C-scan stacking. We followed-up patients with cystoid macular edema, pigment epithelium detachment, macular hole, venous branch occlusion, and vitreoretinal tractions during their course of therapy. The new imaging method illustrates the reduction of cystoid volume, e.g. after intravitreal injections of either angiostatic drugs or steroids. C-scans are used for appreciation of lesion diameters, visualisation of pathologies involving the vitreoretinal interface, and quantification of retinal thickness change. The combined OCT-SLO system creates both topographic and tomographic images of the retina. New therapeutic options can be followed-up closely by observing changes in lesion thickness and cyst volumes. For clinical use further studies are needed.

Imaging Through Opaque Corneas Using Anterior Segment Optical Coherence Tomography

To investigate the capability of the prototype AC Cornea OCT (Ophthalmic Technologies Inc., Toronto, Ontario, Canada) for imaging eyes with opaque corneas. More than 50 eyes of patients were included in the study. The density of opacification influenced the ability of OCT to reveal anterior segment details. Imaging was limited by shadows cast by abnormal pigmentation or vascularity within the cornea. However, the system's unique coronal perspective capability was helpful in revealing occult spatial relationships. The AC Cornea OCT is valuable for examining eyes with opaque corneas and provides cross-sectional and coronal views helpful in formulating specific management strategies.

Evaluation of peripapillary detachment in pathologic myopia with en face optical coherence tomography

A newly recognized lesion in pathologic myopia is peripapillary detachment of the retinal pigment epithelium (RPE) and retina. Recently introduced en face optical coherence tomography (OCT) provides not only cross-sectional but also coronal scans of the retina, and allows lateral extent visualization and thickness measurement of lesions. Three patients presenting bilateral peripapillary yellow-orange lobulated area in high myopia have been evaluated with fluorescein angiography (FA), indocyanine green angiography (ICGA), en face OCT (OCT/SLO; Ophthalmic Technologies Inc, Toronto, Canada), and Humphrey visual field analyzer. In all eyes, en face OCT has shown the presence of a peripapillary sub-RPE nonreflective area. The lateral extent of this area was clearly detectable and the measurement of its thickness was obtained. We detected a cleft in the RPE at one edge of the cavitation in two eyes, vascular tractions and vitreoretinal tractions in two eyes, a macular hole with posterior retinal detachment, and small areas of RPE detachment nonconnected with the peripapillary detachment in one eye. In the four eyes presenting a proper central fixation, glaucomatous visual field defects were evident. En face OCT has allowed to evaluate the thickness and the lateral extent of the peripapillary detachment. Therefore, its use could be important in determining the size and grading of these lesions at first visit, and to detect minimal changes of width and thickness during follow-up as an alternative to fluorescein angiography.

Implantable Miniature Telescope for the Treatment of Visual Acuity Loss Resulting from End-Stage Age-Related Macular Degeneration: 1-Year Results

To evaluate the safety and efficacy of an implantable visual prosthetic device (IMT; VisionCare Ophthalmic Technologies, Saratoga, CA) in patients with bilateral, end-stage age-related macular degeneration (AMD). Prospective, open-label, multicenter clinical trial with fellow eye controls. A total of 217 patients (mean age, 76 years) with AMD and moderate to profound bilateral central visual acuity loss (20/80-20/800) resulting from bilateral untreatable geographic atrophy, disciform scars, or both were enrolled. A visual prosthetic device (implantable telescope), designed to enlarge retinal images of the central visual field, was implanted monocularly in the capsular bag after lens extraction. Fellow eyes were not implanted to provide peripheral vision and served as controls. Study patients participated in 6 visual rehabilitation visits after surgery. Best-corrected distance visual acuity (BCDVA) and best-corrected near visual acuity (BCNVA), quality-of-life scores from the National Eye Institute 25-item Visual Function Questionnaire (NEI VFQ-25) and the Activities of Daily Life scale, endothelial cell density (ECD), and incidence of complications and adverse events. At 1 year, 67% of implanted eyes achieved a 3-line or more improvement in BCDVA versus 13% of fellow eye controls (P<0.0001). Fifty-three percent of implanted eyes achieved a 3-line or more improvement in both BCDVA and BCNVA versus 10% of fellow eyes (P<0.0001). Mean BCDVA and BCNVA improved 3.5 lines and 3.2 lines, respectively, in implanted eyes versus 0.8 lines and 1.8 lines, respectively, in fellow eyes (P<0.0001). Change in visual acuity was not related to lesion type. Mean NEI VFQ-25 scores improved by more than 7 points from baseline (P<0.01) on 7 of 8 relevant subscales. Eleven eyes did not receive the device because of an aborted procedure. Endothelial cell density was reduced by 20% at 3 months and 25% at 1 year. The decrease in ECD was correlated with postsurgical edema (P<0.0001), and there was no evidence that endothelial cell loss is accelerated by ongoing endothelial trauma after implantation. This implantable visual prosthesis can improve visual acuity and quality of life in patients with moderate to profound visual impairment caused by bilateral, end-stage AMD.

Optic Nerve Measurements by 3D Ultrasound-Based Coronal "C-scan" Imaging

Twenty-three normal eyes were examined with the Intensity Profiling technique of 3D I-Scan and 52 normal eyes with the Automated technique of OTI-Scan 1000 ultrasound systems (Ophthalmic Technologies Inc., Toronto, Ontario, Canada). With the eye looking straight, the probe was applied on the temporal sclera. Scanning generated 3D image files. Coronal optic nerve measurements were obtained 3 mm behind the globe. The mean optic nerve sheath diameter was 4.8 mm (standard deviation = 0.6; range, 3.9 to 5.9 mm) with the Intensity Profiling technique, and 5.4 mm (standard deviation = 0.4; range, 4.4 to 6.0 mm) with the Automated technique. 3D ultrasound imaging can be used to obtain optic nerve measurements in vivo. Both the Intensity Profiling and the Automated techniques yielded measurements similar to current magnetic resonance imaging and computed tomography scan reports. Coronal "C-scan" sectioning can be used as a screening tool to measure optic nerve diameter prior to magnetic resonance imaging or computed tomography.