Dynamic imaging of accommodation by swept-source anterior segment optical coherence tomography.

PURPOSE: To study the accommodation process in normal eyes using a commercially available clinical system based on swept-source anterior segment optical coherence tomography (AS-OCT). SETTING: Ophthalmology Department, University of Parma, Italy. DESIGN: Evaluation of diagnostic technology. METHODS: Right eyes were analyzed using swept-source AS-OCT (Casia SS-1000). The optical vergence of the internal coaxial fixation target was adjusted during imaging to obtain monocular accommodation stimuli with different amplitudes (0, 3.0, 6.0, and 9.0 diopters [D]). Overlapping of real and conjugate OCT images enabled imaging of all the anterior segment optical surfaces in a single frame. Central corneal thickness (CCT), anterior chamber depth (ACD), and lens thickness were extracted from the OCT scans acquired at different static accommodation stimulus amplitudes. The crystalline lens was analyzed dynamically during accommodation and disaccommodation by acquiring sequential OCT images of the anterior segment at a rate of 8 frames per second. The lens thickness was extracted from the temporal sequence of OCT images and plotted as a function of time. RESULTS: The study analyzed 14 eyes of 14 subjects aged 18 to 46 years. During accommodation, the decrease in the ACD was statistically significant (P < .05), as were the increase in the lens thickness (P < .001) and the slight movement forward of the lens central point (P < .01). The CCT and anterior chamber width measurements did not change statistically significantly during accommodation. The lens thickness at 0 D was positively correlated with age (P < .01). CONCLUSION: High-resolution real-time imaging and biometry of the accommodating anterior segment can be effectively performed using a commercially available swept-source AS-OCT clinical device. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.

Swept-source anterior segment optical coherence tomography in late-onset capsular block syndrome: high-resolution imaging and morphometric modifications after posterior capsulotomy.

PURPOSE: To study the characteristics of late-onset capsular block syndrome (CBS) using swept-source anterior segment optical coherence tomography (AS-OCT) and assess morphometric variations after treatment with neodymium:YAG (Nd:YAG) laser posterior capsulotomy. SETTING: Ophthalmology, University of Parma, Parma, Italy. DESIGN: Case series. METHODS: Patients with late-onset CBS had an ophthalmology evaluation, including slitlamp photography and AS-OCT, before and 1 month after ND:YAG laser posterior capsulotomy. The diameter of the anterior capsulorhexis, the posterior displacement of the posterior capsule, and the anterior chamber depth (ACD) were measured using AS-OCT. Measurements before and after Nd:YAG laser posterior capsulotomy were compared using the paired t test. RESULTS: The study evaluated 6 patients. Slitlamp examination showed accumulation between the intraocular lens (IOL) and the posterior capsule of milky-white or particulate liquefied material that appeared hyperreflective on AS-OCT and caused posterior displacement of the posterior capsule (mean 1.38 mm). The diameter of the anterior capsulorhexis (mean 4.5 mm) was smaller than the IOL optic in all cases. After uneventful Nd:YAG laser posterior capsulotomy, the corrected distance visual acuity improved in all patients (P<.01). The ACD (IOL position) and refraction did not change significantly after the capsulotomy (P=.15 and P=.36, respectively). CONCLUSIONS: Anterior segment OCT allowed accurate imaging and measurement of anterior segment parameters in late-onset CBS. No displacement of the IOL was found after treatment with Nd:YAG laser posterior capsulotomy. Neodymium:YAG laser posterior capsulotomy was an effective and safe therapy in the 6 late-onset CBS cases.

Membrane frizzled-related protein gene-related ophthalmological syndrome: 30-month follow-up of a sporadic case and review of genotype-phenotype correlation in the literature.

PURPOSE: To report a new sporadic case of membrane frizzled-related protein gene (MFRP)-related syndrome with a 30-month follow-up, and to review the literature for genotype-phenotype correlation in MFRP mutations. METHODS: A complete ophthalmological evaluation was performed at presentation and 30 months later, including best-corrected visual acuity test, slit lamp examination, fundoscopy, kinetic perimetry, electroretinography, fundus imaging (color, red-free, and autofluorescence), and morphologic-biometric analysis of the eye structures with an optical biometer, anterior-segment optical coherence tomography, retinal optical coherence tomography, and a confocal scanning laser for optic nerve head study. Polymerase chain reaction amplification of DNA obtained from peripheral blood lymphocytes and nucleotide sequencing of the complete MFRP gene were performed. The literature on cases of posterior microphthalmos and retinitis pigmentosa associated with MFRP mutations was reviewed. RESULTS: A 33-year-old female patient presented with posterior microphthalmos, retinitis pigmentosa with patches of retinal pigmented epithelium atrophy and scarce pigment mobilization, foveoschisis, and optic nerve drusen. After 30 months, progression of rod-cone retinal degeneration was detected. One obligate carrier showed a normal eye phenotype. A homozygote mutation in the MFRP gene (c.492delC), predicting a truncated protein (P166fsX190), was identified with genetic analysis. To our knowledge, 17 cases of MFRP-related syndrome have been reported in the literature, including the patient described herein. The phenotype of the syndrome, expressivity, and age of onset varied among and within the affected families. However, all patients sharing homozygous mutation c.492delC (alternatively named c.498delC) showed a complete phenotype (including foveoschisis and optic nerve head drusen), and similar fundus characteristics. CONCLUSIONS: A new sporadic case of MFRP-related syndrome is reported. Review of the literature showed variability in the phenotype, but initial elements of genotype-phenotype correlation have been identified in patients sharing the mutation of the present case.

Corneal thickness mapping by 3D swept-source anterior segment optical coherence tomography.

PURPOSE: To assess accuracy and repeatability of central corneal thickness (CCT) measurements obtained by swept-source anterior segment optical coherence tomography (AS-OCT), spectral-domain retinal OCT with corneal module and ultrasound pachymetry (USP), and to assess repeatability of pachymetric mapping with AS-OCT. METHODS: 50 healthy volunteers were recruited. A single, experienced operator analysed the right eye of each participant twice in the same session with AS-OCT ('corneal map' routine), retinal OCT and USP. CCT measurements were compared using repeated-measures analysis of variance, Bonferroni test, Pearson correlation and Bland-Altman plots. Repeatability of thickness maps and CCT measurements were assessed using Alpha of Cronbach, intraclass correlation coefficient (ICC) and coefficient of repeatability. RESULTS: Mean CCT±SD was 540±28.9 µm for AS-OCT, 544±29.5 µm for retinal OCT and 549.3±31.7 µm for USP; the differences were statistically significant (p<0.01). CCT measurements obtained with the three instruments were highly correlated: r was 0.965 for AS-OCT/USP, 0.962 for retinal OCT/USP and 0.984 for AS-OCT/retinal OCT comparison. The repeatability of CCT measurements was higher for AS-OCT than for the other devices (p<0.001). Repeatability of pachymetric maps was excellent (ICC=0.999). CONCLUSIONS: Pachymetric maps by swept-source AS-OCT showed excellent repeatability. CCT measurements obtained by AS-OCT, USP and retinal OCT were highly correlated although not identical.

Simultaneous Descemet stripping automated endothelial keratoplasty and aphakic iris-fixated intraocular lens implantation: a case series.

PURPOSE: To report 3 cases of simultaneous Descemet stripping automated endothelial keratoplasty (DSAEK) and aphakic iris-fixated intraocular lens (IOL) implantation in patients with aphakia and bullous keratopathy. METHODS: We retrospectively documented the clinical characteristics of patients before and after simultaneous DSAEK and aphakic iris-fixated IOL implantation undergoing operation between November 2008 and September 2009. RESULTS: None of the cases showed any intraoperative complications. During the postoperative period, the corneal lenticule was clear and well-attached, and the iris-fixated IOL was well-positioned. CONCLUSIONS: Simultaneous DSAEK and aphakic iris-fixated IOL implantation can be used successfully and simultaneously in patients with aphakia and bullous keratopathy.