Fondazione G.B. Bietti IRCCS

Rome, Italy

Fondazione G.B. Bietti IRCCS

Rome, Italy
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Carroll J.,Medical College of Wisconsin | Kay D.B.,Medical College of Wisconsin | Scoles D.,University of Rochester | Dubra A.,Medical College of Wisconsin | Lombardo M.,Fondazione G.B. Bietti IRCCS
Current Eye Research | Year: 2013

The array of therapeutic options available to clinicians for treating retinal disease is expanding. With these advances comes the need for better understanding of the etiology of these diseases on a cellular level as well as improved non-invasive tools for identifying the best candidates for given therapies and monitoring the efficacy of those therapies. While spectral domain optical coherence tomography offers a widely available tool for clinicians to assay the living retina, it suffers from poor lateral resolution due to the eye's monochromatic aberrations. Ophthalmic adaptive optics (AO) is a technique to compensate for the eye's aberrations and provide nearly diffraction-limited resolution. The result is the ability to visualize the living retina with cellular resolution. While AO is unquestionably a powerful research tool, many clinicians remain undecided on the clinical potential of AO imaging-putting many at a crossroads with respect to adoption of this technology. This review will briefly summarize the current state of AO retinal imaging, discuss current as well as future clinical applications of AO retinal imaging, and finally provide some discussion of research needs to facilitate more widespread clinical use. © Informa Healthcare USA, Inc.


Savini G.,Fondazione GB Bietti IRCCS | Naeser K.,Regions Hospital Randers
Investigative Ophthalmology and Visual Science | Year: 2015

PURPOSE. To investigate the influence of posterior corneal astigmatism, surgically-induced corneal astigmatism (SICA), intraocular lens (IOL) orientation, and effective lens position on the refractive outcome of toric IOLs. METHODS. Five models were prospectively investigated. Keratometric astigmatism and an intended SICA of 0.2 diopters (D) were entered into model 1. Total corneal astigmatism, measured by a rotating Scheimpflug camera, was used instead of keratometric astigmatism in model 2. The mean postoperative SICA, the actual postoperative IOL orientation, and the influence of the effective lens position were added, respectively, into models 3, 4, and 5. Astigmatic data were vectorially described by meridional and torsional powers. A set of equations was developed to describe the error in refractive astigmatism (ERA) as the difference between the postoperative refractive astigmatism and the target refractive astigmatism. RESULTS. We enrolled 40 consecutive eyes. In model 1, ERA calculations revealed significant cylinder overcorrection in with-the-rule (WTR) eyes (meridional power =-0.59 ± 0.34 D, P < 0.0001) and undercorrection in against-the-rule (ATR) eyes (0.32 ± 0.42 D, P = 0.01). When total corneal astigmatism was used instead of keratometric astigmatism (model 2), the ERA meridional power decreased in WTR (-0.13 ± 0.42 D) and ATR (0.07 ± 0.59 D) eyes, both values being not statistically significant. Models 3 to 5 did not lead to significant improvement. CONCLUSIONS. Posterior corneal astigmatism exerts the highest influence on the ERA after toric IOL implantation. Basing calculations on total corneal astigmatism rather than keratometric astigmatism improves the prediction of the residual refractive astigmatism. © 2015 The Association for Research in Vision and Ophthalmology, Inc.


Lombardo M.,Fondazione G.B. Bietti IRCCS | Serrao S.,Fondazione G.B. Bietti IRCCS | Ducoli P.,Fondazione G.B. Bietti IRCCS | Lombardo G.,CNR Institute for Chemical and Physical Processes
Ophthalmic and Physiological Optics | Year: 2013

Purpose: To investigate the distribution of cone density and spacing as well as the preferred packing arrangement of the cone mosaic as a function of retinal eccentricity. Methods: An adaptive optics retinal camera (rtx1, www.imagine-eyes.com) was used to obtain images of the parafoveal cone mosaic in nineteen healthy volunteers. Cone density and spacing were estimated for each subject (both eyes) using a sampling window of 80 × 80 pixels, at 250-, 450-, 650- and 1100-μm eccentricities from the fovea along the nasal and temporal retina of both eyes. The inter-subject and intra-subject variation of cone density and spacing were calculated via Coefficient of Variation (CoV). Cone packing arrangement was assessed using Voronoi analysis; calculations were done over 1024 × 128 pixels image sections of the cone mosaic across the horizontal meridian from 200- to 1050-μm eccentricities. Results: The inter-subject variation of parafoveal cone density ranged between 10% and 15% (p < 0.001) and the intra-subject variation of cone density was lower than 8% in all subjects, except for two. The cone spacing values showed a moderate inter-subject (CoV<7%; p < 0.001) and a low intra-subject variation (CoV<4% in all subjects, except for two cases). In the parafoveal region, 40-50% of cones were hexagonally arranged; the percentage of non-hexagonal Voronoi tiles increased at greater eccentricities. Conclusion: The use of multiple and complementary metric descriptors allows for a more detailed description of packing distribution and preferred arrangement of cone photoreceptors across the parafoveal retina. © 2013 The Authors Ophthalmic & Physiological Optics © 2013 The College of Optometrists.


Lombardo M.,Fondazione G.B. Bietti IRCCS | Lombardo G.,CNR Institute for Chemical and Physical Processes | Lomoriello D.S.,Fondazione G.B. Bietti IRCCS | Ducoli P.,Fondazione G.B. Bietti IRCCS | And 2 more authors.
Retina | Year: 2013

PURPOSE:: To investigate the variation and symmetry of cone density distribution along the nasal and temporal retina of fellow eyes. METHODS:: An adaptive optics retinal camera (rtx1; Imagine Eyes) was used to obtain images of the parafoveal cone mosaic in 20 healthy subjects. Cone density was estimated at 250, 420, 760, and 1,300 μm eccentricity from the fovea along the nasal and temporal retina of both eyes in each subject. The coefficient of variation and the intraclass correlation coefficient were used to calculate the variation and absolute agreement of cone density between the same retinal eccentricity locations of fellow eyes, respectively. RESULTS:: A considerable variation of cone density between subjects was found at all eccentricities along the nasal and temporal retina (intersubject coefficient of variation ≥ 11%, P < 0.001). The intrasubject variation of cone density was, however, moderate (coefficient of variation ≤ 13% in 95% of the subjects); a high agreement was, on average, found between the cone density estimates at the same eccentricity along the nasal and temporal retina of fellow eyes (intraclass correlation coefficient ≥ 0.86, P < 0.001). CONCLUSION:: Cone density follows a symmetrical distribution between fellow eyes. A systematic distribution of parafoveal cones between fellow eyes may provide an anatomical basis for the involvement of the photoreceptor layer in the first step of binocular spatial sampling. © by Ophthalmic Communications Society, Inc.


Lombardo M.,Fondazione G.B. Bietti IRCCS | Serrao S.,Fondazione G.B. Bietti IRCCS | Ducoli P.,Fondazione G.B. Bietti IRCCS | Lombardo G.,Vision Engineering | Lombardo G.,CNR Institute for Chemical and Physical Processes
Journal of Cataract and Refractive Surgery | Year: 2012

Purpose: To evaluate the variation in higher-order ocular wavefront aberrations and the Nyquist limit of resolution of the cone mosaic (N c) in a population of young healthy subjects and the relation to axial length (AL). Setting: Fondazione G.B. Bietti IRCCS, Rome, Italy. Design: Case series. Methods: An adaptive optics retinal camera prototype (rtx1) was used to image the cone mosaic. Cone density and N c were calculated at fixed eccentricity between 260 μm and 600 μm from the foveal center. Ocular higher-order wavefront aberrations were measured using the OPD Scan II device. The coefficient of variation (CoV) was used to analyze the variation in optical and retinal parameters. The correlation of optical and retinal parameters with AL was performed using Pearson analysis. Results: Twelve subjects (age 24 to 38 years; AL 22.61 to 26.63 mm) were evaluated. A high interindividual variation in the higher-order wavefront aberrations was found, ranging from 26% for corneal higher-order aberrations (HOAs) to 41% for intraocular HOAs. The CoV of cone density and N c were 16% and 5%, respectively. The decline in cone density and N c with AL was statistically significant at all retinal eccentricities (R 2 > 0.44, P<.001). Conclusions: Although there appeared to be random variation in the eye's optical wavefront aberration from subject to subject, the cone-packing density and N c were highly correlated with AL. Although the eye's overall image optical quality in the emmetropic group and the myopic group was comparable, the spatial sampling of the cone mosaic decreased with increasing AL. © 2012 ASCRS and ESCRS.


Lombardo M.,Fondazione G.B. Bietti IRCCS | Parravano M.,Fondazione G.B. Bietti IRCCS | Serrao S.,Fondazione G.B. Bietti IRCCS | Ducoli P.,Fondazione G.B. Bietti IRCCS | And 2 more authors.
Retina | Year: 2013

PURPOSE:: To illustrate a noninvasive method to analyze the retinal capillary lumen caliber in patients with Type 1 diabetes. METHODS:: Adaptive optics imaging of the retinal capillaries were acquired in two parafoveal regions of interest in eyes with nonproliferative diabetic retinopathy and unaffected controls. Measures of the retinal capillary lumen caliber were quantified using an algorithm written in Matlab by an independent observer in a masked manner. Comparison of the adaptive optics images with red-free and color wide fundus retinography images was also assessed. RESULTS:: Eight eyes with nonproliferative diabetic retinopathy (eight patients, study group), no macular edema, and preserved visual acuity and eight control eyes (eight healthy volunteers; control group) were analyzed. The repeatability of capillary lumen caliber measurements was 0.22 μm (3.5%) with the 95% confidence interval between 0.12 and 0.31 μm in the study group. It was 0.30 μm (4.1%) with the 95% confidence interval between 0.16 and 0.43 μm in the control group. The average capillary lumen caliber was significantly narrower in eyes with nonproliferative diabetic retinopathy (6.27 ± 1.63 μm) than in the control eyes (7.31 ± 1.59 μm, P = 0.002). CONCLUSION:: The authors demonstrated a noninvasive method to analyze, with micrometric scale of resolution, the lumen of retinal capillaries. The parafoveal capillaries were narrower in patients with Type 1 diabetes and nonproliferative diabetic retinopathy than in healthy subjects, showing the potential capability of adaptive optics imaging to detect pathologic variations of the retinal microvascular structures in vaso-occlusive diseases. © by Ophthalmic Communications Society, Inc.


Serrao S.,Fondazione G.B. Bietti IRCCS | Lombardo G.,CNR Institute for Chemical and Physical Processes | Ducoli P.,Fondazione G.B. Bietti IRCCS | Rosati M.,Fondazione G.B. Bietti IRCCS | Lombardo M.,Fondazione G.B. Bietti IRCCS
Journal of Refractive Surgery | Year: 2013

PURPOSE: To evaluate the changes of corneal topography following femtosecond laser and manual clear corneal incision (CCI). METHODS: Inflation testing was performed in 14 human eye globes to evaluate the topographic response of the cornea to CCIs. In seven samples (femtosecond laser group), a 2.75-mm three-plane CCI was created using the iFS femtosecond laser (Abbott Medical Optics, Inc., Santa Ana, CA); the remaining seven samples (control group) received a 2.75-mm manual CCI using disposable angled knives. Topographic maps of the anterior and posterior cornea were acquired using a Scheimpflug topographer Pentacam HR (Oculus Optikgeräte GmbH, Wetzlar, Germany). Keratometric data were used to analyze the curvature changes of the cornea. The changes of corneal astigmatism were analyzed by vector analysis. RESULTS: After CCI, the mean change of the anterior keratometric power was 0.04 ± 0.39 and 0.05 ± 0.51 diopters (D) (analysis of variance, P > .05) in the femtosecond laser and control groups, respectively. The mean change (P > .05) of the posterior corneal keratometric power was 0.16 ± 0.19 and 0.15 ± 0.18 D, respectively. The average change of the anterior and posterior corneal astigmatism vector magnitude was 0.17 D or less in both groups (P > .05). A slight against-the-rule astigmatic change of the anterior and posterior corneal interfaces was found after both CCI techniques. CONCLUSION: The 2.75-mm three-plane CCI created with femtosecond laser showed minimal changes of the anterior and posterior corneal topography, comparable with those of single-plane angled manual incision. Copyright © SLACK Incorporated.


Lombardo M.,Fondazione G.B. Bietti IRCCS | Serrao S.,Fondazione G.B. Bietti IRCCS | Ducoli P.,Fondazione G.B. Bietti IRCCS | Lombardo G.,CNR Institute for Chemical and Physical Processes
Biomedical Optics Express | Year: 2013

We assessed the agreement between sampling windows of different size and orientation on packing density estimates in images of the parafoveal cone mosaic acquired using a flood-illumination adaptive optics retinal camera. Horizontal and vertical oriented sampling windows of different size (320x160 μm, 160x80 μm and 80x40 μm) were selected in two retinal locations along the horizontal meridian in one eye of ten subjects. At each location, cone density tended to decline with decreasing sampling area. Although the differences in cone density estimates were not statistically significant, Bland-Altman plots showed that the agreement between cone density estimated within the different sampling window conditions was moderate. The percentage of the preferred packing arrangements of cones by Voronoi tiles was slightly affected by window size and orientation. The results illustrated the high importance of specifying the size and orientation of the sampling window used to derive cone metric estimates to facilitate comparison of different studies. © 2013 Optical Society of America.


Lombardo M.,Fondazione G.B. Bietti IRCCS | Pucci G.,University of Calabria | Barberi R.,University of Calabria | Lombardo G.,Vision Engineering Italy S.r.l. | Lombardo G.,CNR Institute for Chemical and Physical Processes
Journal of Cataract and Refractive Surgery | Year: 2015

Understanding ultraviolet (UV) interaction with the human corneal tissue is of interest among corneal specialists given the widespread application of corneal crosslinking. This article reviews the current knowledge of light interaction with the cornea in the UV wavelength range. It also uses a novel experimental study to illustrate the role of 2 important corneal properties that have not yet been clarified: the epithelial contribution to overall UVA corneal absorbance and the regional anisotropy of UVA light transmittance. Finally, it presents the most recent insights into how different methods of UVA light irradiation and corneal soaking with riboflavin influence the outcome of corneal crosslinking. Financial Disclosure No author has a financial or proprietary interest in any material or method mentioned. © 2015 ASCRS and ESCRS.


PURPOSE:: To measure posterior corneal astigmatism (PCA) and investigate its influence on total corneal astigmatism (TCA) in eyes with keratoconus. METHODS:: Keratometric astigmatism (KA), PCA, and TCA were investigated by means of a dual Scheimpflug analyzer in patients with keratoconus. Vector analysis was carried out with the Næser polar value method. RESULTS:: We enrolled 119 eyes. PCA magnitude averaged 0.77 ± 0.43 diopters (D) and exceeded 0.50, 1.00, and 2.00 D in 73.9%, 21.8%, and 16.8% of eyes, respectively. PCA averaged 0.95 ± 0.48, 0.55 ± 0.28, and 0.70 ± 0.35 D in eyes with with-the-rule (WTR), against-the-rule (ATR), and oblique astigmatism. The steepest posterior meridian was oriented vertically (between 61 and 119 degrees) in 55.5% of eyes, thus generating ATR astigmatism. The difference between the location of the steepest meridian of KA and that of TCA was >10 degrees in 8.4% of eyes. On average, KA overestimated TCA in eyes with WTR astigmatism by 0.16 D and underestimated TCA in eyes with ATR astigmatism by 0.22 D. The PCA power oriented along the steeper anterior corneal meridian averaged −0.83 ± 0.40, −0.40 ± 0.37, and −0.53 ± 0.43 D for WTR, ATR, and obliquely astigmatic eyes, respectively. Linear regression disclosed a statistically significant correlation (P < 0.0001, r = 0.16) between the meridional powers of TCA and PCA. CONCLUSIONS:: In eyes with keratoconus, PCA displays large, variable values and is correlated to TCA. The influence of PCA on TCA cannot be disregarded when planning astigmatism correction by toric intraocular lenses. Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved.

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