EN FACE OPTICAL COHERENCE TOMOGRAPHY AND OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY OF INNER RETINAL DIMPLES AFTER INTERNAL LIMITING MEMBRANE PEELING FOR FULL-THICKNESS MACULAR HOLES.

PURPOSE: To quantitatively and qualitatively evaluate the microvascular and structural abnormalities associated with inner retinal dimpling after internal limiting membrane peeling for full-thickness macular holes using sequential en face optical coherence tomography (OCT) and OCT angiography. METHODS: Thirteen eyes of 13 patients with idiopathic full-thickness macular holes were enrolled in the study. Patients were treated with pars plana vitrectomy, internal limiting membrane peeling, and gas tamponade. Subjects were evaluated preoperatively and at postoperative Months 1, 3, and 6. At each visit, patients underwent a comprehensive ophthalmologic examination, en face OCT and OCT angiography. The morphology and number and proportionate area of inner retinal dimples were analyzed. Vessel density of the superficial vascular complex at all visits was also measured. RESULTS: Inner retinal dimples were identified 1 month after surgery in all cases. The number and proportionate area of inner retinal dimples significantly increased over the follow-up period (P = 0.05). Preoperative vessel density of the superficial vascular complex was 17.9 ± 1.9 and did not change significantly over the follow-up period (P = 0.15). CONCLUSION: Inner retinal dimples are identified with en face OCT as early as the first month after internal limiting membrane peeling for idiopathic full-thickness macular holes and progressively increase in number and proportionate area in the subsequent 3 to 6 months after surgery. This may be the result of progressive deturgescence of the nerve fiber layer in the postoperative period.

Clinical results of ab interno trabeculotomy using the trabectome in patients with uveitic glaucoma.

IMPORTANCE: To evaluate the safety and efficacy of ab interno trabeculotomy (AIT) (trabecular ablation) with the trabectome in patients with uveitic glaucoma. BACKGROUND: Traditional glaucoma filtration surgeries in the uveitic patient population come with a higher risk of complications such as failure and hypotony. DESIGN: Retrospective observational cohort study. PARTICIPANTS: All patients diagnosed with uveitic glaucoma were included in this study. Patients were excluded if they have less than 12 months of follow-up. METHODS: All patients who received AIT alone or combined with phacoemulsification. MAIN OUTCOME MEASURES: Major outcomes include intraocular pressure (IOP), number of glaucoma medications and secondary glaucoma surgery, if any. Kaplan-Meier method was used for survival analysis and success was defined as IOP ≤21 mmHg, at least 20% IOP reduction from baseline for any two consecutive visits after 3 months, no additional glaucoma medications, and no secondary glaucoma surgery. RESULTS: A total of 45 eyes, 45 patients, with an average age of 52 years were included in the study. The majority were Japanese (40%) and underwent AIT alone (71%). IOP was reduced from 29.2 ± 8.0 to 16.7 ± 4.6 mmHg at 12 months (P < .01*), while the number of glaucoma medications was reduced from 4.0 ± 1.0 to 2.5 ± 1.6 (P < .01*). Survival rate at 12 months was 91%. Six cases required secondary glaucoma surgery and no other serious complication were reported. CONCLUSIONS AND RELEVANCE: The trabectome AIT procedure appears to be effective in reducing IOP in uveitic glaucoma patients. Although no statistically significant difference was found in the number of glaucoma medications, a decreasing trend was found.

Implantation of a second glaucoma drainage device.

PURPOSE: To evaluate success rates in controlling intraocular pressure (IOP) after implantation of a second glaucoma drainage device (GDD) with a Baerveldt glaucoma implant in patients with refractory glaucoma, with a secondary aim of reducing the need for postoperative glaucoma medications. MATERIAL AND METHODS: This retrospective, noncomparative, interventional study included patients undergoing a second GDD for uncontrolled glaucoma from a tertiary care glaucoma service. Data were obtained from the medical records for the preoperative period and after the 1st, 15th, and 30th day, 3, 6, and 12 months, and then yearly until the last postoperative visit. Visual acuity, IOP, and number of glaucoma medications (NGM) from the follow-up visits were compared to baseline. Success and failure criteria were analyzed based on IOP level or need of glaucoma medications. RESULTS: Forty-nine patients were studied, with a mean follow-up time of 25 ± 21 months. The mean preoperative IOP was 23.7 ± 8.2 mmHg, and decreased to 14.8 ± 4.0 mmHg after 1 year, 14.4 ± 3.9 mmHg after 2 years, and 16.6 ± 8.5 mmHg after 3 years. The mean preoperative NGM was 3.4 ± 1.3, and decreased to 2.0 ± 1.8 after 1 year, 2.5 ± 1.6 after 2 years, and 2.8 ± 2.0 after 3 years. Absolute success was 9% after 1 year for a postoperative IOP between 5 and 18 mmHg, and 76% for a postoperative IOP between 5 and 21 mmHg. The qualified success was 88% at the first and second years and 83% at the third year. CONCLUSION: With up to 3 years of follow-up, a second glaucoma drainage device was successful in reducing IOP to below 21 mmHg, but not as successful below 18 mmHg. The success rate is improved with the use of glaucoma medications with up to 3 years of follow-up.

Effects of diurnal, lighting, and angle-of-incidence variation on anterior segment optical coherence tomography (AS-OCT) angle metrics.

BACKGROUND: First reported study to assess the effect of diurnal variation on anterior chamber angle measurements, as well as, to re-test the effects of lighting and angle-of-incidence variation on anterior chamber angle (ACA) measurements acquired by time-domain anterior segment optical coherence tomography (AS-OCT). METHODS: A total of 30 eyes from 15 healthy, normal subjects underwent anterior chamber imaging using a Visante time-domain AS-OCT according to an IRB-approved protocol. For each eye, the inferior angle was imaged twice in the morning (8 am - 10 am) and then again in the afternoon (3 pm - 5 pm), under light meter-controlled conditions with ambient room lighting 'ON' and lights 'OFF', and at 5° angle of incidence increments. The ACA metrics measured for each eye were: angle opening distance (AOD, measured 500 and 750 µm anterior from scleral spur), the trabecular-iris-space area (TISA, measured 500 and 750 µm anterior from scleral spur), and scleral spur angle. Measurements were performed by masked, certified Reading Center graders using the Visante's Internal Measurement Tool. Differences in measurements between morning and afternoon, lighting variations, and angle of incidence were compared. RESULTS: Mean age of the participants was 31.2 years (range 23-58). Anterior chamber angle metrics did not differ significantly from morning to afternoon imaging, or when the angle of incidence was offset by 5° in either direction away from the inferior angle 6 o'clock position. (p-value 0.13-0.93). Angle metrics at the inferior corneal limbus, 6 o'clock position (IC270), with room lighting 'OFF', showed a significant decrease (p < 0.05) compared to room lighting 'ON'. CONCLUSIONS: There does not appear to be significant diurnal variation in AS-OCT parameters in normal individuals, but lighting conditions need to be strictly controlled since variation in lighting led to significant variability in AS-OCT parameters. No changes in ACA parameters were noted by varying the angle-of-incidence, which gives confidence in being able to perform longitudinal studies in approximately the same area (plus/minus 5° of original scan location).

Endoscopic cyclophotocoagulation versus second glaucoma drainage device after prior aqueous tube shunt surgery.

BACKGROUND: To evaluate the efficacy in controlling intraocular pressure (IOP) with endoscopic cyclophotocoagulation (ECP) versus implantation of a second glaucoma drainage device (GDD-2) in the treatment of uncontrolled glaucoma with a prior aqueous tube shunt. DESIGN: A nonrandomized retrospective chart review. PARTICIPANTS: Patients with refractory glaucoma following a failed initial tube shunt (Baerveldt Glaucoma Implant 350), who underwent ECP or GDD-2 with Baerveldt Glaucoma Implant as a second surgery. Twenty-five eyes underwent ECP, and 48 eyes received a GDD-2. METHODS: ECP or second tube-shunt surgery. MAIN OUTCOME MEASURES: Reduction in IOP and antiglaucoma medications, and Kaplan-Meier survival with success defined as lOP ≥ 5 mmHg and ≤ 21 mmHg and ≥ 20% reduction from preoperative IOP. Secondary outcome measures were visual acuity and the presence of any postoperative complications. RESULTS: Both ECP and GDD-2 significantly lowered IOP (Student's t test) and number of antiglaucoma medications (Wilcoxon paired signed rank test). There were no significant differences in postoperative IOP (Student's t test) or antiglaucoma medications (Mann Whitney test) between ECP and GDD-2 at 6 and 12 months. There was also no difference in the Kaplan-Meier survival outcomes between the two groups. CONCLUSION: Both ECP and GDD-2 are both effective as second surgeries for refractory glaucoma that has failed a prior aqueous shunt.

Identification of anterior chamber angle parameters with a portable SD-OCT device compared to a non-portable SD-OCT.

The aim of this study is to compare a portable spectral domain optical coherence tomography (SD-OCT) device with a non-portable SD-OCT for the identification of anterior chamber angle parameters based on location of Schwalbe's line (SL) and to measure their reproducibility. 99 eyes from 46 normal, healthy participants underwent imaging of the inferior iridocorneal angle with the iVue and Cirrus SD-OCT under well-controlled low-light conditions. SL-angle opening distance (SL-AOD) and SL-trabecular iris space area (SL-TISA) were measured by masked, certified graders at the Doheny Image Reading Center using customized Image J grading software. Inter- and intrainstrument, as well as inter- and intraobserver reproducibility of SL-AOD and SL-TISA measurements were evaluated with intraclass correlation coefficients (ICCs) and Bland-Altman plots with limits of agreement. The mean SL-AOD was 0.814 ± 0.315 mm with the iVue and 0.797 ± 0.294 mm with the Cirrus. The mean SL-TISA was 0.247 ± 0.112 mm2 with iVue and 0.259 ± 0.113 mm2 with Cirrus. Interinstrument correlation coefficients (r) were 0.93 (P < 0.0001), 0.92 (P < 0.0001), and 0.92 (P < 0.0001) for SL_AOD and SL_TISA, respectively. Intraclass correlation coefficient showing the degree of agreement among SL-AOD and SL-TISA was 0.923 (95 % confidence interval 0.885-0.948) and 0.921 (95 % confidence interval 0.883-0.947) for both devices. The agreement for intrainstrument (ICCs > 0.95), intragrader (ICCs > 0.93), and intergrader (ICCs > 0.96) was excellent. Excellent agreement between the two devices was also documented with Bland-Altman analysis. Both instruments provide consistent and reproducible measurements of anterior chamber angle metrics.

SWEPT-SOURCE OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY OF THE OPTIC DISK IN OPTIC NEUROPATHY.

PURPOSE: To evaluate the optic nerve head microvasculature in eyes with acute and chronic optic neuropathies using swept-source optical coherence tomography angiography. METHODS: In this cross-sectional, observational study, optical coherence tomography angiography images were obtained from the optic nerve heads of 21 eyes of 12 patients with optic disk edema, pseudoedema and atrophy, and 12 eyes of 6 healthy subjects using a 1,050-nm optical coherence tomography angiography (Topcon DRI OCT; Triton). Peripapillary vasculature was assessed within five horizontal slabs consisting of the nerve fiber layer (NFL), ganglion cell layer, inner nuclear layer, choroidal layer, and full-thickness retinal layer. In addition, prelaminar and laminar slabs were evaluated. Vessel density was measured within a 3.4-mm diameter circle centered on the optic disk. RESULTS: The abnormalities of the peripapillary capillary network were most apparent in the NFL and total retinal slabs. In eyes with disk edema, an increase or decrease in the visibility of the peripapillary capillary network was observed. Eyes with optic atrophy had decreased visibility of peripapillary capillary network corresponding to the region or sector of NFL thinning. Prelaminar capillary network was dilated and tortuous in eyes with disk edema. The mean vessel density was statistically significantly lower and the mean NFL thickness was statistically significantly thinner in eyes with optic atrophy compared with normal eyes (both P < 0.001). Vessel density was significantly correlated with the peripapillary NFL thickness (P < 0.001). CONCLUSION: Optical coherence tomography angiography provides high-resolution, noninvasive visualization of the microvasculature of the optic nerve head and peripapillary region. Changes in the microvasculature in this region may prove useful in better characterization of optic neuropathies.

Clinical results of ab interno trabeculotomy using the Trabectome in patients with pigmentary glaucoma compared to primary open angle glaucoma.

BACKGROUND: To evaluate outcomes of Trabectome on pigmentary glaucoma (PG) patients compared to matched controls with primary open angle glaucoma (POAG). DESIGN: Prospective comparison study PARTICIPANTS: A total of 101 POAG cases were matched with 101 PG cases. METHODS: Data of the patients diagnosed with PG or POAG was obtained from Trabectome Study Group Database. A one-to-one exact matching was performed between POAG and pigmentary cases based on type of surgery, baseline IOP and baseline number of glaucoma medications. IOP and number of glaucoma medications were compared between groups by Wilcoxon test. Success was defined as IOP ≤ 21 mmHg, at least 20% IOP reduction from baseline for two consecutive visits after 3 months and no secondary surgery. MAIN OUTCOME MEASURES: Success rate after Trabectome surgery in PG patients. RESULTS: Baseline IOP for PG is 24.4 ± 7.7 mmHg and 24.2 ± 7.5 mmHg for POAG (P = 1.0), while baseline number of glaucoma medications was 2.8 ± 1.2 mmHg for PG and 2.8 ± 1.2 mmHg for POAG (P = 1.0). Postoperative IOP values at 12 months were 17.1 ± 5.0 for PG cases and 15.9 ± 4.2 mmHg for POAG cases. Postoperative number of glaucoma medications at 12 month was 2.1 ± 1.4 in PG cases and 2.4 ± 1.3 in POAG cases. There was no statistically significant difference between groups in IOP or number of medications at any time point. Survival rate at 12 months was 92% and 86% in PG and POAG, respectively (P = 0.47). Six PG cases and nine POAG cases required secondary surgery. CONCLUSION: Trabectome provides similar outcomes to PG patients and POAG patients.

Early Worsening of Retinopathy in Type 1 and Type 2 Diabetes After Rapid Improvement in Glycaemic Control: A Systematic Review.

To systematically review the epidemiology of early worsening of diabetic retinopathy (EWDR) after substantial improvements in glycaemic control and evaluate characteristics including risk factors. This systematic review was registered with PROSPERO (CRD42020158252). An electronic literature search was performed according to PRISMA guidelines using MEDLINE, EMBASE, PubMed, Web of Science, Scopus and Cochrane databases and manual reference for the articles published until 2020. Published full-text English language articles that report data on diabetic retinopathy in people with diabetes experiencing a rapid, substantial decrease in HbA1c after going through intensive therapy were included. All articles were screened, data were extracted and methodological quality was evaluated by two independent reviewers using a priori criteria. A total of 346 articles were identified after the removal of duplicates. Data were extracted from 19 full-text articles with a total of 15,588 participants. Included studies varied considerably in terms of patient selection, timing and method of assessing the eye and retinopathy classification. EWDR was reported to occur in a wide range of prevalences; 3.3-47% of participants within 3-84 months after intensification of glycaemic control. Risk factors for EWDR included long duration of diabetes, long-term uncontrolled hyperglycemia, amplitude of and baseline retinopathy severity in both type 1 and type 2 diabetes. The occurrence of EWDR and progression of retinopathy were found to have an association with the amplitude of HbA1c reduction. EWDR has been described in a proportion of people with intensification of glycaemic control. However, the prevalence remains unclear because of methodological differences in the identified studies. Future interventional studies should report retinopathy and visual outcomes using standardized protocols.

CONVERSION OF FOCAL CHOROIDAL EXCAVATION WITH THE ONSET OF CENTRAL SEROUS CHORIORETINOPATHY: REPORT OF 2 CASES AND REVIEW OF THE LITERATURE.

PURPOSE: To describe two cases of focal choroidal excavation (FCE) conversion in patients with central serous chorioretinopathy. METHODS: Case report and literature review of cases of FCE conversion. RESULTS: A 35-year-old asymptomatic pregnant patient was found to have conforming FCE on spectral domain optical coherence tomography of the right eye during hydroxychloroquine screening. Three months later, she presented with decreased vision in the right eye and subretinal fluid in both eyes secondary to central serous chorioretinopathy. Spectral domain optical coherence tomography revealed that her FCE had changed to nonconforming type. A 40-year-old male patient was found to have nonconforming FCE and subretinal fluid in his right eye on spectral domain optical coherence tomography. On follow-up, spectral domain optical coherence tomography demonstrated resolution of subretinal fluid and conversion of nonconforming FCE to conforming type. Literature review showed that most cases of FCE remain stable over time. Conversion from nonconforming FCE to conforming type has been described after photodynamic therapy or anti-vascular endothelial growth factor therapy. Conversion from conforming to nonconforming type has been described in 2 cases that developed subretinal fluid in the setting of acute central serous chorioretinopathy. CONCLUSION: Our cases and literature review suggest that nonconforming FCE is the result of persistent subretinal fluid. Further studies are necessary to determine whether symptomatic nonconforming SRF needs treatment to reduce subretinal fluid.

Application of optical coherence tomography angiography in diabetic retinopathy: a comprehensive review.

Optical coherence tomography angiography (OCTA) is a noninvasive method that enables visualization of blood flow within retinal vessels down to the size of capillaries by detecting motion contrast from moving blood cells. OCTA provides a fast and safe procedure to assess retinal microvasculature with higher contrast and resolution than conventional fluorescence angiography. The different capillary plexuses are displayed separately and their perfusion density can be quantified. Imaging capabilities such as these have led to an emerging field of clinical application for OCTA in vascular diseases such as diabetic retinopathy (DR). Evaluation of parameters such as parafoveal capillary perfusion density could be a biomarker for disease diagnosis and progression. Typical microvascular changes in DR such as capillary nonperfusion, microaneurysms, intraretinal microvascular abnormalities, and neovascularization can be reliably detected in optical coherence tomography angiograms, characterized in detail and attributed to the different capillary plexuses. Monitoring of these lesions in vivo gives potential novel insight into the pathophysiology in DR. The aim of this article is to summarize the potential applications/utility of OCTA in DR reported in the literature.

Intravitreal bevacizumab as rescue therapy following treatment failure with laser photocoagulation in retinopathy of prematurity.

PURPOSE: To evaluate the efficacy of intravitreal bevacizumab (IVB) in case of treatment failure with laser photocoagulation in retinopathy of prematurity (ROP). METHODS: A retrospective review of infants treated with IVB injection due to treatment failure with laser photocoagulation was performed. The anatomical results and complications were evaluated after treatment. RESULTS: 9 eyes of 6 premature infants with a mean gestational age of 26.8 ± 3.0 weeks (range, 23-32 w) and mean birth weight of 958 ± 319 g (range, 600-1400 g) were identified. Six of the eyes had zone 1 disease, and all of these eyes were classified as aggressive posterior ROP (APROP). Three of the eyes had zone 2 disease, and one of these eyes was classified as APROP, and the other two eyes were classified as high-risk pre-threshold disease. All of the eyes showed regression of the disease except one patient, both eyes of whom progressed to stage 4A. None of the patients developed ocular and systemic complications at the end of the six-month follow-up period. CONCLUSION: IVB could be an option in patients with ROP in whom laser photocoagulation failed.

Trabeculectomy Outcomes After Glaucoma Drainage Device Surgery.

PURPOSE: To evaluate outcomes of trabeculectomy with adjunctive mitomycin C in patients with uncontrolled intraocular pressure (IOP) after glaucoma drainage device implantation. MATERIALS AND METHODS: Consecutive patients who had undergone a trabeculectomy after GDD were reviewed. The primary outcome was surgical success with stratified IOP targets based on the following criteria: (A) IOP<18 mm Hg and IOP reduction of 20%; (B) IOP<15 mm Hg and IOP reduction of 25%; (C) IOP<12 mm Hg and IOP reduction of 30%. Secondary outcomes were number of glaucoma medications, complications, and need for additional glaucoma surgery. RESULTS: Twenty eyes (19 patients) were included for analysis. Median follow-up and age were 3.7 years (range, 1.1 to 10.2 y) and 64.2 years (range, 25.2 to 85.6 y), respectively. Mean IOP (±SD) has dropped from 19.3±4.2 mm Hg preoperatively to 9.8±2.2 mm Hg at 1 year, 8.8±3.2 mm Hg at 3 years and 8.4±1.5 mm Hg at 5 years (P<0.001 for all). Hypotony maculopathy was the only serious complication (2/19 patients; 10%) that needed surgical revision. The cumulative success rate (±SD) for criterion A and B were 73.2% (±10.0%) and 68.2% (±9.5%), respectively, between the first and fifth year of follow-up, for criterion C it was 49.1% (±10.8%) at the first year and 32.7% (±12%) between the second and fifth year of follow-up. CONCLUSIONS: Trabeculectomy is a viable surgical option to treat IOP that is uncontrolled after GDD implantation.

Ab interno Schlemm's Canal Surgery.

In primary open-angle glaucoma, the site of greatest resistance to aqueous outflow is thought to be the trabecular meshwork (TM) and inner wall of Schlemm's canal. Augmentation of the conventional (trabecular) outflow pathway can facilitate physiologic outflow and subsequently lower intraocular pressure. The most recent approach to enhancing the conventional outflow pathway is via an internal approach to the TM and Schlemm's canal. Ab interno Schlemm's canal surgery includes 4 novel surgical approaches: (1) removal of the TM and inner wall of Schlemm's canal by an internal approach (ab interno trabeculectomy), (2) implantation of a microstent to bypass the TM, (3) disruption of the TM and inner wall of Schlemm's canal via an internal approach (ab interno trabeculotomy), and (4) dilation of Schlemm's canal via an internal approach (ab interno canaloplasty). The first category includes the Trabectome (Neomedix, Tustin, CA, USA), and Kahook Dual Blade (New World Medical, Rancho Cucamonga, CA, USA). The second category includes the iStent (Glaukos, Laguna Hills, CA, USA), as well as the investigational Hydrus Microstent implant (Ivantis, Irvine, CA, USA). The third category includes gonioscopic-assisted transluminal trabeculotomy (iSciences catheter; Ellex, Adelaide, Australia), and 360° suture trabeculotomy (TRAB360, Sight Sciences, Menlo Park, CA, USA). The fourth category includes ab interno canaloplasty or AbiC (Ellex), and Visco360 (Sight Sciences). In contrast to external filtration surgeries, such as trabeculectomy and aqueous tube shunt, these procedures are categorized as internal filtration surgeries and are performed from an internal approach via gonioscopic guidance. Published results suggest that these surgical procedures are both safe and efficacious for the treatment of open-angle glaucoma.

Optical Coherence Tomography Angiography of the Optic Disc; an Overview.

Different diseases of the optic disc may be caused by or lead to abnormal vasculature at the optic nerve head. Optical coherence tomography angiography (OCTA) is a novel technology that provides high resolution mapping of the retinal and optic disc vessels. Recent studies have shown the ability of OCTA to visualize vascular abnormalities in different optic neuropathies. In addition, quantified OCTA measurements were found promising for differentiating optic neuropathies from healthy eyes.

Short-Term Clinical Results of Ab Interno Trabeculotomy Using the Trabectome with or without Cataract Surgery for Open-Angle Glaucoma Patients of High Intraocular Pressure.

Purpose. To assess the safety and efficacy of Trabectome procedure in patients with preoperative intraocular pressure (IOP) of 30 mmHg or higher. Methods. All patients who had underwent Trabectome stand-alone or Trabectome combined with phacoemulsification were included. Survival analysis was performed by using Kaplan-Meier, and success was defined as IOP ≤ 21 mmHg, 20% or more IOP reduction from baseline for any two consecutive visits after 3 months, and no secondary glaucoma surgery. Results. A total of 49 cases were included with an average age of 66 (range: 13-91). 28 cases had Trabectome stand-alone and 21 cases had Trabectome combined with phacoemulsification. Mean IOP was reduced from a baseline of 35.6 ± 6.3 mmHg to 16.8 ± 3.8 mmHg at 12 months (p < 0.01∗), while the number of medications was reduced from 3.1 ± 1.3 to 1.8 ± 1.4 (p < 0.01∗). Survival rate at 12 months was 80%. 9 cases required secondary glaucoma surgery, and 1 case was reported with hypotony at day one, but resolved within one week. Conclusion. Trabectome seems to be safe and effective in patients with preoperative IOP of 30 mmHg or greater. Even in this cohort with high preoperative IOP, the end result is a mean IOP in the physiologic range.

Impact of image quality on OCT angiography based quantitative measurements.

BACKGROUND: To study the impact of image quality on quantitative measurements and the frequency of segmentation error with optical coherence tomography angiography (OCTA). METHODS: Seventeen eyes of 10 healthy individuals were included in this study. OCTA was performed using a swept-source device (Triton, Topcon). Each subject underwent three scanning sessions 1-2 min apart; the first two scans were obtained under standard conditions and for the third session, the image quality index was reduced using application of a topical ointment. En face OCTA images of the retinal vasculature were generated using the default segmentation for the superficial and deep retinal layer (SRL, DRL). Intraclass correlation coefficient (ICC) was used as a measure for repeatability. The frequency of segmentation error, motion artifact, banding artifact and projection artifact was also compared among the three sessions. RESULTS: The frequency of segmentation error, and motion artifact was statistically similar between high and low image quality sessions (P = 0.707, and P = 1 respectively). However, the frequency of projection and banding artifact was higher with a lower image quality. The vessel density in the SRL was highly repeatable in the high image quality sessions (ICC = 0.8), however, the repeatability was low, comparing the high and low image quality measurements (ICC = 0.3). In the DRL, the repeatability of the vessel density measurements was fair in the high quality sessions (ICC = 0.6 and ICC = 0.5, with and without automatic artifact removal, respectively) and poor comparing high and low image quality sessions (ICC = 0.3 and ICC = 0.06, with and without automatic artifact removal, respectively). CONCLUSIONS: The frequency of artifacts is higher and the repeatability of the measurements is lower with lower image quality. The impact of image quality index should be always considered in OCTA based quantitative measurements.

Repeatability, reproducibility, agreement characteristics of 2 SD-OCT devices for anterior chamber angle measurements.

OBJECTIVE: To evaluate the agreement, reproducibility, and repeatability of 2 spectral domain optical coherence tomography (SD-OCT) devices in Schwalbe's line (SL)-based anterior chamber angle parameters. METHODS: The inferior anterior chamber angle of 65 eyes from 65 participants (33 right eyes and 32 left eyes) were scanned twice with the Nidek RS 3000 Advanced SD-OCT and Cirrus SD-OCT. SL angle opening distance (SL-AOD) and SL trabecular-iris-space area (SL-TISA) were graded by masked certified graders at the Doheny Image Reading Center. RESULTS: The mean SL-AOD/SL-TISA was 617.3 ± 237.9 µm/0.211 ± 0.086 mm2 for the Cirrus and 633.7 ± 219.3 µm/0.218 ± 0.080 mm2 for the Nidek RS 3000 Advanced SD-OCT. The repeatability (intraclass correlation coefficients [ICCs] >0.936) and intergrader reproducibility (ICCs >0.915) in SL-AOD and SL-TISA with Cirrus OCT were excellent. The repeatability (ICCs >0.948) and intergrader reproducibility (ICCs >0.709) in SL-AOD and SL-TISA with the Nidek RS 3000 Advanced SD-OCT were moderate to good. Moderate agreement between the 2 devices was also documented with a mean difference of -15.3 (limits of agreement [LoA] -246.5 to 277.1) mm for SL-AOD and 0.006 (LoA -0.096 to 0.108) mm in SL-TISA. CONCLUSION: Both devices were able to provide consistent angle measurements, but repeatability and reproducibility were better in Cirrus SD-OCT than in Nidek RS 3000 Advanced SD-OCT.

Image artefacts in swept-source optical coherence tomography angiography.

PURPOSE: To describe optical coherence tomography angiography (OCTA) image artefacts in eyes with and without ocular pathologies. METHODS: The OCTA images of healthy subjects and patients with age-related macular degeneration, diabetic retinopathy and retinal vascular occlusions were retrospectively reviewed. All OCTA images were obtained using a swept-source OCTA instrument (Triton, Topcon). The frequency of various image artefacts including segmentation, banding, motion, projection, masking, unmasking, doubling of the retinal vessels, blink, stretching, out-of-window and crisscross artefacts was assessed. The impact of the artefact on the grading of the images for the foveal avascular zone in deep and superficial retinal layers, capillary non-perfusion and choroidal neovascularisation (CNV) was evaluated. RESULTS: OCTA images of 57 eyes of 48 subjects including 23 eyes (40.3%) with CNV, 13 eyes (22.8%) with dry age-related macular degeneration, 9 eyes (15.7%) with cystoid macular oedema due to diabetic retinopathy or retinal vein occlusion and 12 normal eyes (21.1%) were available for evaluation. At least one type of artefact was present in the images from 51 eyes (89.4%). Banding artefact, segmentation, motion, unmasking, blink, vessel doubling, masking and out-of-window artefacts were found in 51 (89.4%), 35 (61.4%), 28 (49.1%), 9 (15.8%), 5 (8.8%), 1 (1.7%), 1 eye (1.7%) and 1 eye (1.7%), respectively. Projection artefact, stretch artefact or crisscross artefact was not observed. Banding, motion and segmentation artefacts were statistically significantly more frequent in eyes with ocular pathology compared with control eyes (all p<0.001). Eyes with choroidal diseases had significantly higher rate of segmentation error in the choriocapillaris slab compared with eyes with only retinal disease (p=0.02). In nine eyes (17.6%), the artefacts were deemed severe enough by the graders to preclude accurate grading of the image. CONCLUSIONS: Image artefacts occur frequently in OCTA images. The artefacts are more frequent in eyes with pathology.

Choroidal thickness and structural glaucoma parameters in glaucomatous, preperimetric glaucomatous, and healthy eyes using swept-source OCT.

PURPOSE: To evaluate choroidal thickness (CT) and its relationship with retinal nerve fiber layer (RNFL) and ganglion cell-inner plexiform layer thickness (GCIPLT) in glaucomatous, preperimetric glaucomatous, and healthy eyes using swept-source optical coherence tomography (SS-OCT). METHODS: Fifty eyes with primary open-angle glaucoma, 20 eyes with preperimetric glaucoma, and 20 age-matched healthy eyes were enrolled. Three-dimensional wide-field (12 × 9 mm) images were obtained using a SS-OCT instrument. Peripapillary CT and RNFL thickness, as well as macular CT and GCIPLT, were recorded. The correlation of the CT with nerve fiber layer and GCIPLT measurements was assessed. The association between CT and potential confounding variables including age, sex, axial length, intraocular pressure, and central corneal thickness was also examined. RESULTS: Mean peripapillary CTs were 111.7 ± 41.7, 127.7 ± 40.1, and 120.8 ± 35.4 µm in glaucomatous, preperimetric glaucomatous, and normal eyes, respectively. There was statistically significant but weak correlation for the mean RNFL and mean peripapillary CT in glaucomatous subjects (r = 0.341, p = 0.04). There was a significant correlation between RNFL thickness and peripapillary CT in 1, 2, 5, and 6 clock hours of glaucomatous eyes (r = 0.410, p = 0.005; r = 0.316, p = 0.03; r = 0.346, p = 0.02; r = 0.35, p = 0.04, respectively). Mean macular CT was 181.5 ± 70.5, 187.4 ± 65.5, and 185.4 ± 76.4 µm in glaucomatous, preperimetric glaucomatous, and healthy eyes, respectively (p = 0.7). There was no statistically significant correlation between the mean GCIPLT and mean macular CT in all subjects (p>0.05). CONCLUSIONS: Choroidal thinning and its correlation with other parameters in patients with glaucoma should be further investigated with the proprietary software of SS-OCT.