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

Clues from Crouzon: Insights into the potential role of growth factors in the pathogenesis of myelinated retinal nerve fibers.

PurposeWe present a case of bilateral extensive peripapillary myelinated retinal nerve fibers (MRNF) in an individual with Crouzon syndrome, an inherited form of craniosynostosis caused by overactivation of fibroblast growth factor receptor 2. As a secondary aim, we examine the utility of optical coherence tomography (OCT) angiography for visualization of peripapillary vasculature obscured by myelination on other imaging modalities.MethodsA 24-year-old woman with Crouzon syndrome was evaluated for suspected optic neuritis in the right eye.ResultsFunduscopic examination and photography revealed the incidental finding of bilateral extensive peripapillary MRNF. OCT angiography provided excellent visualization of peripapillary retinal vessels, which were partially obscured by myelination on other imaging modalities.ConclusionsThis association of Crouzon syndrome with bilateral peripapillary MRNF may lend insight into the developmental control of optic nerve myelination, the pathogenesis of MRNF, and the potential role of growth factors in these processes. Further, OCT angiography allowed for excellent blood vessel visualization in this case of MRNF

Assessment of Anterior Segment Measurements with Swept Source Optical Coherence Tomography before and after Ab Interno Trabeculotomy (Trabectome) Surgery

Purpose. To compare the changes of anterior segment parameters, assessed by swept source anterior segment optical coherence tomography (AS-OCT) after combined Trabectome-cataract surgery and Trabectome-only surgery in open angle glaucoma patients. Methods. Thirty-eight eyes of 24 patients with open angle glaucoma were scanned with swept source AS-OCT before and 4 weeks after combined Trabectome-cataract or Trabectome-only surgery. Intraocular pressure, number of medications, and AS-OCT parameters, such as angle opening distance at 500 and 750 μm from the scleral spur (AOD500 and AOD750), trabecular-iris space area at 500 and 750 mm2 (TISA500, TISA750), angle recess area at 500 and 750 mm2 (ARA500, ARA750), trabecular iris angle (TIA), anterior chamber depth (ACD), anterior chamber width (ACW), and anterior chamber volume (ACV), were obtained before the surgery. These parameters were compared to evaluate whether the outcome of the surgery differed among the patients after the surgery. The width of the trabecular cleft was also measured for both groups. Results. The reduction of IOP and number of medications was found to be statistically significant in both groups (p<0.001). ACD, ACV, and angle parameters such as AOD 500/750, TISA 500/750, ARA 500/750, and TIA500 showed significantly greater changes from the preoperative values to postoperative 1st month values in combined Trabectome-cataract surgery group (p<0.05), whereas Trabectome-only group did not show statistically significant difference (p>0.05). There was no statistically significant difference between two groups for the width of the trabecular cleft (p=0.7). Conclusion. Anterior chamber angle parameters measured with swept source AS-OCT may be useful for evaluating glaucoma patients before and after Trabectome surgery with or without cataract surgery

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

Impact of image quality on OCT angiography based quantitative measurements

Abstract 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

Utility of anterior segment swept-source optical coherence tomography for imaging eyes with antecedent ocular trauma

Purpose: To evaluate the utility of swept source optical coherence tomography (SS-OCT) for the analysis of anterior segment structures in cases with previous traumatic eye injuries. Observations: We report three eyes of three patients with anterior segment traumatic eye injury and highlight the role of SS-OCT in their evaluation and management. This technology enabled us to visualize the structural details of anterior segment of the eye and augment the clinical examination in our patients. Given that it is non-invasive and that there is no contact involved, it may be an ideal imaging modality for traumatic eye injuries for viewing the details before and after any clinical intervention especially in the sub-acute setting. Conclusions: The anterior segment SS-OCT is a useful device allowing non-invasive, non-contact, real-time, cross-sectional anterior segment images of eyes with previous ocular trauma

Iris atrophy and erosion caused by an anterior-chamber angle-supported phakic intraocular lens

Dhubhghaill, Sorcha S Ni/0000-0002-1115-7834; Tassignon, Marie-Jose/0000-0001-8302-8006WOS: 000347671300034PubMed: 25532647We report a case in which an angle-supported phakic IOL was implanted to correct high myopia. Subsequently, the patient experienced photophobia, glare, halo, and loss of visual acuity and became concerned about the cosmetically deforming aspect of her eye. Findings included endothelial cell loss, cataract, pupil ovalization, and severe iris atrophy. The pIOL was removed and cataract surgery was performed, followed by implantation of a bag-in-the-lens IOL, but successful surgical repair of the iris was not possible because of severe iris atrophy

Swept-source OCT angiography imaging of the foveal avascular zone and macular capillary network density in diabetic retinopathy

PURPOSE We compared the area of the foveal avascular zone (FAZ) and macular capillary network density at different retinal layers using swept-source optical coherence tomography angiography (OCT-A) in normal individuals and patients with diabetic retinopathy (DR). METHODS Images (a 3 × 3 mm cube centered on the fovea) were acquired in 40 eyes of 22 normal individuals and 28 eyes of 18 patients with varying levels of DR using a swept-source OCT-A device (central wavelength 1050 nm; A-scan-rate of 100,000 scans per second). En face images of the retinal vasculature were generated from the superficial and deep retinal layers (SRL/DRL). Quantitative analysis of the vessel density (VD) and FAZ area was performed. Vessel density was assessed as the ratio of the retinal area occupied by vessels. RESULTS Among the DR subjects (mean age, 72 years; 61% male), 35.7% of the eyes had mild, 35.7% moderate, and 7.1% severe nonproliferative DR (NPDR), and 21.4% and proliferative DR (PDR). The mean FAZ area in patients with DR and in normal individuals was 0.518 and 0.339 mm2, respectively, for the SRL (P = 0.003), and 0.615 and 0.358 mm2, respectively, for the DRL (P < 0.001). The mean VD (ratio) at the SRL and DRL was statistically significantly lower in patients with DR (SRL, P < 0.001; DRL, P = 0.028). CONCLUSIONS Swept-source OCT-A of the microcirculation in eyes of patients with DR can be used to quantitatively demonstrate alterations in the FAZ and VD in the SRL/DRL of the macula compared to normal eyes. Future longitudinal studies may use these metrics to evaluate changes over time or in response to treatment