Marco Ciancaglini

Reliability of nerve fiber layer thickness measurements using optical coherence tomography in normal and glaucomatous eyes

OBJECTIVE To evaluate the reliability of nerve fiber layer (NFL) thickness measurements by optical coherence tomography (OCT) in normal and glaucomatous eyes. DESIGN Prospective, comparative, observational case series and instrument validation study. PARTICIPANTS Twenty-four glaucomatous patients were compared with 24 gender- and age-matched normal subjects. METHODS Each individual underwent OCT measurements of NFL thickness. Five repetitions of a series of scans on five separate occasions within a 0.5-month period were performed. Each eye was scanned at three different nerve head programs (1.5 radius [R], R = 1.73 mm, 2.0 R). For each option (1.5 R, R = 1.73 mm, and 2.0R) and region (superior, inferior, temporal, nasal, and overall mean), variance components and intraclass correlation coefficients were determined using repeated measures regression. In these models, NFL thickness, as measured by OCT, was assumed to have three variance components: intersubject, intervisit (within-subject between-dates), and intravisit (within-subject within-date). The intraclass correlation coefficient (intersubject variance/total variance) was used as a measure of reliability. MAIN OUTCOME MEASURES Measurements of NFL thickness using OCT were performed. RESULTS Reliability values, as measured by intraclass correlation coefficients, resulted as follows: 1.5 R, 0.54/0.52 (normal/glaucoma); R = 1.73 mm, 0.50/0.50; 2.0 R, 0.49/0.50. CONCLUSIONS Our results indicate that the recent commercially available OCT provides reliable NFL thickness measurements in both healthy and glaucomatous eyes with each circle radius tested. The greatest amount of variability can be attributed to intersubject differences.

Femtosecond Laser Arcuate Keratotomy for the Correction of High Astigmatism after Keratoplasty

PURPOSE To determine the feasibility and initial outcomes of using a femtosecond laser to perform arcuate keratotomies to correct high post-keratoplasty astigmatism. DESIGN Prospective noncomparative interventional case series. PARTICIPANTS Twelve eyes of 12 consecutive patients (mean age 44.9+/-9.5 years) who presented with a high degree of astigmatism, noncorrectable with spectacles or contact lenses (10 post-penetrating keratoplasty, 2 post-deep lamellar keratoplasty), and were candidates for relaxing incisional corneal surgery. METHODS The Femtec (20/10 Perfect Vision, GmbH, Heidelberg, Germany) femtosecond laser performed paired 90-degree angled arcuate incisions on the graft button. The incision sites and depths were programmed at 1.00 mm inside the graft edge and at 90% of the corresponding local graft thickness, whereas the angular lengths of the cuts were determined by analyzing the locations and extents of the steepest meridians in the topographic map. MAIN OUTCOME MEASURES Changes in uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), mean subjective and topographically determined astigmatism; imaging of incisions by anterior segment optical coherence tomography (AS-OCT); and wound healing by in vivo confocal microscopy (IVCM). RESULTS Postoperative follow-up extended to 6 months. Mean uncorrected logarithm of the minimum angle of resolution (logMAR) BSCVA and UCVA improved from preoperative values of 0.25+/-0.16 and 1.05+/-0.18 to 6-month values of 0.11+/-0.12 (standard deviation) and 0.55+/-0.34, respectively (P<0.05). Mean subjective astigmatism was 7.16+/-3.07 diopters (D) preoperatively and 2.23+/-1.55 D at 1 month after surgery (P = 0.002) and remained stable to the end of follow-up. Anterior segment optical coherence tomography image analysis showed that the depth and location of the incisions were consistent with the preoperative surgical plan. In vivo confocal microscopy showed mild edema and keratocyte activation along the incision edges, together with initial epithelial ingrowth inside the wound, followed by subsequent moderate fibrotic scarring. CONCLUSIONS Arcuate keratotomies performed with the femtosecond laser were effective in reducing post-keratoplasty astigmatism. Laser-generated incisions within the graft button presented precise geometry and reliable depth of incision, with a wound healing pattern characterized by epithelial ingrowth and mild fibrosis. FINANCIAL DISCLOSURE(S) The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Filtering Bleb Functionality: A Clinical, Anterior Segment Optical Coherence Tomography and In Vivo Confocal Microscopy Study

PurposeTo provide a microscopic and macroscopic analysis by a clinical, in vivo confocal microscopy (IVCM) and anterior segment optical coherence tomography (AS-OCT) assessment of filtering blebs after glaucoma surgery. Material and MethodsWe retrospectively analyzed 60 eyes of 48 glaucomatous patients by slit-lamp, IVCM, and AS-OCT examinations. Patients were divided into 2 groups: successful blebs (group 1, 16 patients, 27 eyes) were defined as a one-third reduction in preoperative intraocular pressure without antiglaucoma medications and failed blebs (group 2, 32 patients, 33 eyes) as a less than one-third reduction in preoperative intraocular pressure without therapy. The examinations were performed from 1 to 96 months postoperatively. ResultsDiffuse or cystic clinical patterns were indicative for good functionality whereas flat or encapsulation was indicative for poor functionality. When comparing successful with failed blebs, the IVCM analysis showed a greater number (P=0.014), density (P=0.009), and total area of epithelial microcysts (P=0.017) and a lower density of connective tissue (P=0.006). The AS-OCT analysis showed a lower degree of bleb wall reflectivity (P<0.001). A significant correlation was found between the clinical and AS-OCT parameters, particularly for the cystic (100%) and diffuse (74%) patterns. ConclusionsAll IVCM parameters did correlate well with the bleb functionality whereas, among the AS-OCT parameters, only the bleb wall reflectivity was significantly related to the filtering capability. Clinical and AS-OCT bleb classification showed a significant degree of concordance. As a consequence, simultaneous approach by clinical, microscopic, and tomographic assessment improves the clinicians ability in the postsurgery understanding and management of blebs.

Fundus microperimetry patterns of fixation in type 2 diabetic patients with diffuse macular edema.

Background: Recently developed fundus microperimetry (MP-1; Nidek Technologies, Srl. Vigonza PD, Italy) was used to evaluate fixation patterns and retinal sensitivity in patients who had clinically significant macular edema with a diffuse pattern and type 2 diabetes mellitus. Methods: In a prospective, observational case series study, 84 consecutive patients with type 2 diabetes (84 eyes) who had clinically significant macular edema with a diffuse pattern were studied by means of MP-1. Main outcome measures were fixation stability and position and mean retinal sensitivities within the central 2° and 8° areas. Logarithm of the minimum angle of resolution (logMAR) best-corrected visual acuity (BCVA) was evaluated by means of an Early Treatment of Diabetic Retinopathy Study chart. Foveal thickness was measured by Stratus optical coherence tomography (OCT; Carl Zeiss Meditec, Inc., Dublin, CA). Age, duration of diabetes, hemoglobin A1c (HbA1c) levels, duration of symptoms, history of panretinal photocoagulation, vitreomacular adhesion, and cystoid macular changes were documented. Patients were grouped according to both position of fixation (central or eccentric) and stability of fixation (stable or unstable). Statistical analyses included independent samples t-test, binomial test, Bonferroni correction for multiple comparisons, and generalized linear model univariate analysis. Results: Of 84 eyes, 44 (52.4%) had central fixation, and 40 (47.6%) had eccentric fixation. Of 84 eyes, 34 (40.5%) had stable fixation, and 50 (59.5%) had unstable fixation. In the whole sample, mean central 2° retinal sensitivity ± SD was 6.26 ± 3.19 dB (range, 0–14.80 dB), and mean central 8° retinal sensitivity ± SD was 7.62 ± 2.55 (range, 3.85–14.90 dB); logMAR BCVA ranged from 0.1 to 1.3 (mean ± SD, 0.6 ± 0.29). Mean OCT foveal thickness ± SD was 300.77 ± 66.93 m (range, 220–525 m). Both comparisons between groups (stable vs. unstable and central vs. eccentric) showed statistically significant differences in mean logMAR BCVA, mean central 2° and 8° retinal sensitivities, and mean OCT foveal thickness. Duration of symptoms was significantly longer and HbA1c levels were higher in the groups with deterioration of stability or centrality of fixation. The prevalence of cystoid macular changes was significantly higher in the groups with eccentric or unstable fixation (P < 0.001). Generalized linear model statistical analysis showed that logMAR BCVA was significantly associated with stability of fixation (P = 0.020), mean central 8° retinal sensitivity (P < 0.001), and mean OCT foveal thickness (P < 0.001). The interaction between stability of fixation and mean OCT foveal thickness showed a statistically significant association with logMAR BCVA (P = 0.003). Some eyes with eccentric fixation presented with stable fixation, especially in the presence of long-lasting symptoms, and had better visual acuity than eyes with central, but unstable fixation. Conclusion: Visual acuity, central retinal sensitivity, foveal thickness, duration of symptoms, HbA1c levels, and presence of cystoid macular changes were strongly associated with fixation impairment in type 2 diabetic patients who had clinically significant macular edema with a diffuse pattern. Stability of fixation and foveal thickness play a major role in conditioning BCVA.

Optical Coherence Tomography Angiography in Retinal Vascular Diseases and Choroidal Neovascularization

Purpose. To assess the ability of optical coherence tomography-angiography (OCT-A) to show and analyze retinal vascular patterns and the choroidal neovascularization (CNV) in retinal vascular diseases. Methods. Seven eyes of seven consecutive patients with retinal vascular diseases were examined. Two healthy subjects served as controls. All eyes were scanned with the SD-OCT XR Avanti (Optovue Inc, Fremont CA, USA). Split spectrum amplitude decorrelation angiography algorithm was used to identify the blood flow within the tissue. Fluorescein angiography (FA) and indocyanine green angiography (ICGA) with Spectralis HRA + OCT (Heidelberg Engineering GmbH) were performed. Results. In healthy subjects OCT-A visualized major macular vessels and detailed capillary networks around the foveal avascular zone. Patients were affected with myopic CNV (2 eyes), age-related macular degeneration related (2), branch retinal vein occlusion (BRVO) (2), and branch retinal artery occlusion (BRAO) (1). OCT-A images provided distinct vascular patterns, distinguishing perfused and nonperfused areas in BRVO and BRAO and recognizing the presence, location, and size of CNV. Conclusions. OCT-A provides detailed images of retinal vascular plexuses and quantitative data of pathologic structures. Further studies are warranted to define the role of OCT-A in the assessment of retinovascular diseases, with respect to conventional FA and ICG-A.

Prospective randomized comparison of wavefront-guided and conventional photorefractive keratectomy for myopia with the meditec MEL 70 laser

PURPOSE To study refractive results and aberrometric changes in myopic patients treated with wavefront-guided photorefractive keratectomy (PRK) in comparison with standard PRK. METHODS Sixty eyes of 60 patients with myopic astigmatism were randomly divided into two groups. Group 1 included 30 eyes (mean spherical equivalent refraction -4.39 +/- 1.31 D; range -2.50 to -6.50 D) treated with wavefront-guided PRK using the WASCA workstation and the Asclepion Meditec flying spot MEL 70 excimer laser. Group 2 had 30 eyes (mean spherical equivalent refraction -4.33 +/- 1.22 D; range -2.50 to -6.50 D) that underwent conventional PRK using the same laser, and served as the control group. Wavefront analysis of high order aberrations was performed before and 6 months after surgery. RESULTS Postoperatively, wavefront error increased in both groups (5.0-mm wavefront aperture diameter). Six months after surgery, the eyes that received the WASCA ablation had a smaller increase in root-mean-square (RMS; 70% of increment) compared to the conventional PRK group (139% of increment) (P<.001). In the standard PRK group, all aberrations notably increased; in the wavefront-guided PRK group there was a smaller increase of trefoil and spherical aberrations (P<.001) and a decrease of coma aberrations (P<.001). The smaller increase of wavefront error in the wavefront-guided PRK group compared to the standard PRK group was more evident when preoperative RMS values were higher than 0.4 microm (P<.01). The visual parameters (spherical equivalent refraction, uncorrected and best spectacle-corrected visual acuity) did not show significant differences between the two groups. CONCLUSION Wavefront-guided PRK induced a smaller increase of postoperative wavefront-error compared to conventional PRK, particularly in patients with higher preoperative higher order aberrations.

In vivo confocal microscopy of patients with amiodarone-induced keratopathy.

Purpose. To describe the corneal findings in patients with amiodarone-induced keratopathy by means of in vivo confocal microscopy. Methods. Twenty-two eyes of 11 patients (eight men and three women) receiving amiodarone therapy and 20 eyes of 10 healthy sex-and age-matched control subjects were selected for confocal microscopic examination. The patients were examined by use of a scanning slit corneal confocal microscope (Confoscan 2.0). Five complete scans of the entire cornea were performed for each eye with a total examination time of less than 5 minutes. Results. All patients receiving amiodarone showed the presence of high reflective, bright intracellular inclusions in the epithelial layers. These findings were more evident within the basal cell layers. In the eyes with advanced keratopathy (stages 2 and 3), bright microdots were detectable within the anterior and posterior stroma and on the endothelial cell layer. In the anterior stroma, the keratocyte density in the treated group was reduced compared with values of the control group (p < 0.001), and a markedly irregular aspect of the stromal nerve fibers was found. The main characteristic of this nerve irregularity was represented by the clew-shaped appearance of the nerve trunks. Conclusion. Detailed examination of corneal structure by confocal microscopy shows that amiodarone keratopathy in long-term treated patients presents some findings that are consistent with higher toxicity than was expected and that involve the deep corneal layers.

Treatment of retinal tears and lattice degenerations in fellow eyes in high risk patients suffering retinal detachment: a prospective study

BACKGROUND/AIMS Fellow eye prophylaxis for retinal detachment (RD) is still a controversial issue since opinions are not unanimous regarding the kind of lesions to be treated or the method of treatment. This prospective clinical study aimed to follow the course of vitreoretinal conditions in 150 high risk fellow eyes. METHODS 150 consecutive patients with unilateral rhegmatogenous RD were included in this study. Inclusion criteria were good explorability of fellow eye retinal periphery and one of the following conditions in the fellow eye—aphakia, pseudophakia with capsulotomy, high myopia (>−6D), contralateral eye to a giant retinal tear. Prophylactic treatment (photocoagulation or scleral buckling) was performed in the presence of retinal tears and lattice degenerations. The state of the vitreous body was determined at the beginning of the study and at the end, when RD occurred. RESULTS Follow up ranged from 36 to 132 months. 95 fellow eyes were subjected to laser treatment; five eyes underwent prophylactic surgical treatment. Initially, in the treated group posterior vitreous detachment (PVD) was present in 100 eyes (100% of cases), but as a complete PVD only in 42 of them (42%). 10 eyes in the treated group developed RD during the follow up period. In five of these cases the partial PVD had progressed and a retinal tear in a previously healthy area was the cause of the retinal detachment. In the other five eyes RD apparently developed from previously treated lesions. Progression of PVD was evident in four out of these five eyes. The untreated eyes had no visible degenerative lesions. During follow up eight eyes developed RD. These eyes had no PVD at the beginning of the study, but showed a partial PVD at the time of the diagnosis of RD. CONCLUSION Fellow eyes with pre-existing retinal tears and PVDs can go on to retinal detachment in spite of laser prophylactic treatment. When PVD is not detectable or a partial PVD is present, the progression of posterior vitreous separation can account for retinal tears and RDs arising in formerly healthy areas.

An in vivo confocal microscopy and impression cytology analysis of preserved and unpreserved levobunolol-induced conjunctival changes.

Purpose To provide an in vivo confocal microscopy (IVCM) and impression cytology analysis of preserved- and unpreserved levobunolol-induced changes of conjunctival epithelium. Methods 27 eyes of 27 patients were consecutively randomized to receive preserved or unpreserved levobunolol; all patients had a recent diagnosis of primary open angle glaucoma (POAG) or ocular hypertension and were not previously treated with topical medications. IVCM and impression cytology were performed before and after six months of therapy. Goblet cells density and a conjunctival epithelium regularity index were considered in the IVCM analysis, whereas impression cytology specimens were graded and scored in accordance with Nelsons method. Results After six months of therapy, IVCM and impression cytology parameters showed significant differences with respect to baseline in both groups (p<0.001); significant differences were also found between the two groups (p<0.001). The IVCM analysis showed a goblet cells density reduction (61% and 17% from baseline, respectively in group 1 and 2) (p<0.001) and an higher index of epithelial regularity (p<0.001) in both groups; the impression cytology analysis showed an higher score in both groups (p<0.001). Conclusions All the IVCM and impression cytology parameters correlated well with the conjunctival modifications induced by the topical therapy, suggesting the less toxicity of unpreserved drugs

Prevalence of myopia in open angle glaucoma.

In this study concerning the prevalence of myopia in patients with open angle glaucoma, its distribution was analyzed within the sample tested in relation to the refraction defect size, compared with a control group of non-glaucomatous myopic subjects. The overall myopic rate was 17.2% of the glaucomatous patients; high myopia was more frequent in the subjects with open angle glaucoma (p<0.001) than in the myopic patients, thus appearing as a possible risk factor for the development of glaucoma.