Repeatability of Foveal Measurements Using Spectralis Optical Coherence Tomography Segmentation Software

PURPOSE: To investigate repeatability and reproducibility of thickness of eight individual retinal layers at axial and lateral foveal locations, as well as foveal width, measured from Spectralis spectral domain optical coherence tomography (SD-OCT) scans using newly available retinal layer segmentation software. METHODS: High-resolution SD-OCT scans were acquired for 40 eyes of 40 young healthy volunteers. Two scans were obtained in a single visit for each participant. Using new Spectralis segmentation software, two investigators independently obtained thickness of each of eight individual retinal layers at 0°, 2° and 5° eccentricities nasal and temporal to foveal centre, as well as foveal width measurements. Bland-Altman Coefficient of Repeatability (CoR) was calculated for inter-investigator and inter-scan agreement of all retinal measurements. Spearman's ρ indicated correlation of manually located central retinal thickness (RT0) with automated minimum foveal thickness (MFT) measurements. In addition, we investigated nasal-temporal symmetry of individual retinal layer thickness within the foveal pit. RESULTS: Inter-scan CoR values ranged from 3.1μm for axial retinal nerve fibre layer thickness to 15.0μm for the ganglion cell layer at 5° eccentricity. Mean foveal width was 2550μm ± 322μm with a CoR of 13μm for inter-investigator and 40μm for inter-scan agreement. Correlation of RT0 and MFT was very good (ρ = 0.97, P 0.05); however this symmetry could not be found at 5° eccentricity. CONCLUSIONS: We demonstrate excellent repeatability and reproducibility of each of eight individual retinal layer thickness measurements within the fovea as well as foveal width using Spectralis SD-OCT segmentation software in a young, healthy cohort. Thickness of all individual retinal layers were symmetrical at 2°, but not at 5° eccentricity away from the fovea

Argus II retinal prosthesis system: a review of patient selection criteria, surgical considerations, and post-operative outcomes

Avni P Finn, Dilraj S Grewal, Lejla Vajzovic Department of Ophthalmology, Duke University Eye Center, Durham, NC, USA Abstract: Retinitis pigmentosa (RP) is a group of heterogeneous inherited retinal degenerative disorders characterized by progressive rod and cone dysfunction and ensuing photoreceptor loss. Many patients suffer from legal blindness by their 40s or 50s. Artificial vision is considered once patients have lost all vision to the point of bare light perception or no light perception. The Argus II retinal prosthesis system is one such artificial vision device approved for patients with RP. This review focuses on the factors important for patient selection. Careful pre-operative screening, counseling, and management of patient expectations are critical for the successful implantation and visual rehabilitation of patients with the Argus II device. Keywords: retinal prosthesis, vision rehabilitation, artificial vision, patient selection, retinitis pigmentosa, retinal degeneration, low visio

Acute retinal pigment epithelium detachments after photocoagulation

To characterize the morphology of patterned scanning laser (PASCAL) panretinal photocoagulation. In this prospective cohort study, patients with proliferative diabetic retinopathy or severe nonproliferative diabetic retinopathy with high-risk characteristics, who were treated with PASCAL panretinal photocoagulation as part of their indicated clinical course, were serially imaged with spectral domain optical coherence tomography. Thirty eyes of 25 patients were studied from 1 hour to 21 weeks after laser treatment. Over a quarter (26.1%) of all treatment spots were imaged by spectral domain optical coherence tomography 1 hour after PASCAL panretinal photocoagulation. At 1 hour (±30 minutes) after PASCAL treatment, spectral domain optical coherence tomography demonstrated retinal pigment epithelium detachment in 23 of 27 eyes (85.2%) and in 36.1% of all imaged laser spots. Detachments occurred preferentially at the photocoagulation edges in 48.4% of pigment epithelium detachments (PEDs). Linear regression analysis revealed that average laser power (Pearson's r = 0.671, P 1,200 mW. By a 1-week follow-up, no PEDs were observed, and the retinal pigment epithelium appeared morphologically similar to its preoperative structure by 3 weeks. Patient characteristics (study eye, sex, race, diagnosis, age, preoperative blood glucose, hemoglobin A1C, duration of diabetes, and body mass index) and other PASCAL parameters (number of laser applications, spot size, pulse duration, and average laser fluence) were not significantly associated with PEDs. Retinal pigment epithelium detachment occurs 1 hour after PASCAL treatment over a wide range of laser settings. Laser power and energy are positively correlated with the occurrence of PEDs, which are no longer observed by 1-week follow-up. Future studies might examine various acute posttreatment time points and directly compare the morphology of PASCAL burns with that of longer pulse-duration laser modalities

Optical Coherence Tomography and Wide-Field Fluorescein Angiography in Retinopathy of Prematurity

The advent and adaptation of many imaging modalities promise to revolutionize our understanding of retinopathy of prematurity (ROP) by improving the detection, diagnosis, and monitoring of response to treatment of this disease. Diagnosis and classification of ROP traditionally relies on an eye exam by an ophthalmologist expert in this area who characterizes extent and character of retinal vascularization via indirect ophthalmoscopy. Many tools now exist that allow for data acquisition by nurses, technicians, and other trained staff with the images analyzed in a more centralized location. We will focus on two rapidly evolving technologies, optical coherence tomography (OCT), and wide field fluorescein angiography (FA), to better understand how these tools may change our current understanding and management of ROP

Delay in Retinal Photoreceptor Development in Very Preterm Compared to Term Infants

PURPOSE. We compared photoreceptor development from spectral domain optical coherence tomography (SD-OCT) imaging in very preterm infants (VPT, <32 weeks gestational age) with those of term infants. METHODS. The microanatomy of foveal SD-OCT images obtained at the bedside at 37 to 42 weeks term equivalent postmenstrual age (TEA) was reviewed with qualitative and quantitative analysis of retinal and especially photoreceptor layers in the macula. Measures of maturity included presence of the cone outer segment tips (COST) or the ellipsoid zone (EZ) at foveal center, distance from Bruch's membrane (BM) to the EZ at the foveal center, and radial distance from foveal center to first appearance of the EZ. RESULTS. The incidence of the EZ developed at the foveal center was lower in VPT infants (9/64, 14%) versus term infants (22/47, 47%, P < 0.001) and lower in VPT infants with macular edema (3/46) versus VPT without edema (6/18, P = 0.01). Mean ± SD distance from the foveal center to the visible EZ was 783 ± 440 μm in VPT, and 492 ± 501 μm in term infants, P = 0.002. The height of the BM-to-EZ at the foveal center did not differ in VPT versus term infants. The COST band was not visible in any infant. CONCLUSIONS. Photoreceptor inner and outer segment development in VPT infants appears delayed when compared to term infants, and the photoreceptor RPE junction remains immature in all infants at TEA. Delayed maturation of photoreceptors could contribute to differences in visual function in some VPT infants

Ultra High-Resolution Anterior Segment Optical Coherence Tomography in the Evaluation of Anterior Corneal Dystrophies and Degenerations

To evaluate the clinical usefulness of a spectral-domain ultra high-resolution anterior segment optical coherence tomography (UHR OCT) in examination, diagnosis, and management of various anterior corneal dystrophies and degenerations. Noncomparative case series. Fifty-nine eyes of 38 consecutive patients were enrolled in the study and included 28 eyes of 14 patients with anterior corneal dystrophies, 21 eyes of 19 patients with anterior corneal degenerations or neoplasia, and 10 eyes of 5 patients with normal corneas. Subjects were imaged using a novel custom-built UHR OCT. Images were used to evaluate and describe the characteristics of anterior corneal dystrophies and degenerations. Nineteen patients underwent surgical management, and those histopathologic specimens were analyzed and correlated with the UHR OCT images. Comparison of clinical findings, UHR OCT images, and corresponding histopathologic specimens. The UHR OCT provided clear delineation of corneal anatomic features and pathologic corneal deposits in most cases. The characteristics and depth of these deposits are illustrated and can be localized to specific layers of the cornea. When available, there was significant correlation between UHR OCT images and histopathologic features, providing a noninvasive confirmation of the clinical diagnosis. Ultra high-resolution OCT is an innovative technique to perform in vivo optical biopsies and a promising research and clinical tool for the evaluation of corneal pathologic features in a noninvasive manner. The future use of this novel technology will evolve and increasingly is becoming a vital tool in the clinical and surgical management of corneal diseases. The author(s) have no proprietary or commercial interest in any materials discussed in this article

In vivo morphologic characteristics of Salzmann nodular degeneration with ultra-high-resolution optical coherence tomography

To examine the in vivo morphologic properties of Salzmann nodular degeneration with ultra-high-resolution optical coherence tomography (OCT). Interventional case series. Single-center academic practice. Nineteen eyes of 12 patients with Salzmann nodular degeneration were recruited to participate in the study. Subjects were imaged using novel, custom-built ultra-high-resolution OCT. Images were used to describe in vivo characteristics of subepithelial nodules. Morphometric measurements were made with custom-built software. Ultra-high-resolution OCT findings were compared with histopathologic findings in 3 patients. Identifiable in vivo morphologic characteristics of Salzmann nodular degeneration with ultra-high-resolution OCT. Ultra-high-resolution OCT images demonstrate intraepithelial fibrous nodules with epithelial thinning and corneal surface elevation. The Bowman layer could be differentiated in 9 of 12 patients. The difference between the mean thickness of epithelium above the nodule and the thickness of normal epithelium was statistically significant (P < .0001). The correlation between thickness of the epithelium and thickness of the nodule was statistically significant (r = -0.48; P < .0001). The correlation between thickness of the nodule and total surface thickness (thickness of the epithelium + thickness of the nodule) was statistically significant (r = 0.98; P < .0001). Ultra-high-resolution OCT findings were consistent with histopathologic results. Ultra-high-resolution OCT can be used to noninvasively image the cornea in Salzmann nodular degeneration. This new imaging technique helps us to demonstrate different in vivo morphologic characteristics of Salzmann nodular degeneration

Vision loss reduction with avacincaptad pegol for geographic atrophy: a 12-month post hoc analysis of the GATHER1 and GATHER2 trials

To evaluate the impact of reduction in geographic atrophy (GA) lesion growth on visual acuity in the GATHER trials using categorical outcome measures. Randomized, double-masked, sham-controlled phase 3 trials. Aged ≥50 years with non-center point involving GA and best corrected visual acuity (BCVA) of 25-80 Early Treatment Diabetic Retinopathy Study (ETDRS) letters in the study eye. GATHER1 consisted of 2 parts. In Part 1, 77 patients were randomized 1:1:1 to avacincaptad pegol (ACP) 1 mg, ACP 2 mg, and sham. In Part 2, 209 patients were randomized 1:2:2 to ACP 2 mg, ACP 4 mg, and sham. In GATHER2, patients were randomized 1:1 to ACP 2 mg (n=225) and sham (n=223). A post hoc analysis of 12-month data for pooled ACP 2 mg and sham groups is reported. Proportion of study eyes that experienced ≥10-, ≥15-, or ≥20-BCVA ETDRS letter loss from baseline to month 12; time-to-event analysis of persistent vision loss of ≥10-, ≥15-, or ≥20-BCVA letters from baseline at ≥2 consecutive visits over 12 months; proportion of study eyes with BCVA loss to a level below driving eligibility threshold at month 12 among those eligible to drive at baseline. Lower proportions of study eyes experienced ≥10-, ≥15-, or ≥20-BCVA letter loss from baseline over 12 months with ACP 2 mg (11.6%, 4.0%, and 1.6%, respectively) vs sham (14.1%, 7.6%, and 4.5%, respectively). There was a reduction in the risk of persistent loss of ≥15-BCVA ETDRS letters with ACP 2 mg (3.4%) vs sham (7.8%) through 12 months. A lower proportion of study eyes treated with ACP 2 mg reached the threshold for driving ineligibility vs sham by 12 months. Treatment with ACP 2 mg delayed the risk of progression to persistent vision loss (ie, ≥10-, ≥15-, and ≥20-BCVA letter loss or BCVA loss to a level below driving eligibility threshold) vs sham over 12 months