Ocular vascular occlusive disorders: natural history of visual outcome

Cilioretinal Arteries in Highly Myopic Eyes: A Photographic Classification System and Its Association With Myopic Macular Degeneration

Purpose: To develop a photographic classification for cilioretinal arteries and to investigate its association with myopic macular degeneration (MMD). Methods: One thousand six hundred ninety-two highly myopic eyes of 1,692 patients were included. The presence of a cilioretinal artery was determined by fundus photographs, and a photographic classification was proposed. MMD was classified according to the International META-PM Classification. Associations of the cilioretinal artery and its classifications with MMD and visual acuity were analyzed. Results: Of the eyes tested, 245 (14.5%) had a cilioretinal artery. The cilioretinal arteries were classified into four categories (temporal "cake-fork," 35.92%; temporal "ribbon," 53.47%; "multiple," 6.53%; "nasal," 4.08%) and 3 distributions based on whether its visible branches reached the central foveal area. Eyes with cilioretinal arteries had significantly less MMD of grade ≥3 and better visual acuity than those without (P < 0.01). Multiple linear regression analysis showed that younger age, male sex, shorter axial length, and the presence of a cilioretinal artery were associated with better visual acuity in highly myopic eyes (all P < 0.05). The "nasal" category presented more MMD with grade ≥3 and worse visual acuity than the other categories (P < 0.05), whereas the "multiple" category contained no eyes with MMD grade ≥3. The cilioretinal arteries reaching the central foveal area showed less MMD of grade ≥3 and better visual acuity than those not (P < 0.05). Conclusions: We propose a photographic classification for cilioretinal arteries that has good clinical relevance to visual functions. The cilioretinal artery may potentially afford protection against MMD.

Effects of Switching from Anti-VEGF Treatment to Triamcinolone Acetonide in Eyes with Refractory Macular Edema Associated with Diabetic Retinopathy or Retinal Vein Occlusion

Purpose

To evaluate the efficacy of switching from intravitreal antivascular endothelial growth factor (VEGF) agents to triamcinolone acetonide (TA) in eyes with diabetic macular edema (DME) or with retinal vein occlusion-associated macular edema (RVO-ME) on the resolution of the macular edema (ME).

Methods

The medical records of 11 eyes of 11 patients with DME and 9 eyes of 9 patients with RVO-ME whose MEs were refractory to anti-VEGF treatment were reviewed. The central retinal thickness (CRT), best-corrected visual acuity (BCVA), intraocular pressure (IOP), and the mean interval of the recurrences were measured during the anti-VEGF treatment and after switching to the TA injections.

Results

Switching to TA injections significantly increased the mean interval for recurrences from 9.2 ± 2.7 weeks to 22.3 ± 12.9 weeks in eyes with DME (P = 0.006). In eyes with RVO-ME, the mean period of recurrence was 12.3 ± 5.6 weeks before and 11.6 ± 4.4 weeks after the switch (P = 0.44). The mean interval for recurrence was extended to more than 8 weeks in 7 of 11 eyes with DME, but none of the eyes with RVO-ME had a prolongation of more than 4 weeks. An elevation of the IOP was observed in 3 of the 20 eyes after the TA injection.

Conclusions

These findings indicate that switching to TA injections can be a good option for DME eyes refractory to anti-VEGF injections but not for the RVO-ME eyes.

Carotid artery intima-media thickness, HDL cholesterol levels, and gender associated with poor visual acuity in patients with branch retinal artery occlusion

PURPOSE

To investigate factors associated with poor visual acuity (VA) in branch retinal artery occlusion (BRAO).

METHODS

This was a retrospective cross-sectional study of 72 eyes with BRAO of 72 patients. For statistical comparison, we divided the patients into worse-VA (decimal VA < 0.5) and better-VA (decimal VA > = 0.5) groups. We examined the association of clinical findings, including blood biochemical test data and carotid artery ultrasound parameters, with poor VA.

RESULTS

Median age, hematocrit, hemoglobin and high-density lipoprotein (HDL) differed significantly between the groups (P = 0.018, P < 0.01, P < 0.01, and P = 0.025). There was a tendency towards higher median IMT-Bmax in the worse-VA group (worse-VA vs. better-VA: 2.70 mm vs. 1.60 mm, P = 0.152). Spearman's rank correlation test revealed that logMAR VA was significantly correlated to IMT-Bmax (rs = 0.31, P < 0.01) and IMT-Cmax (rs = 0.24, P = 0.035). Furthermore, logMAR VA was significantly correlated to HDL level (rs = -0.33, P < 0.01). Multivariate logistic regression analysis revealed that IMT-Bmax (odds ratio [OR] = 2.70, P = 0.049), HDL level (OR = 0.91, P = 0.032), and female gender (OR = 15.63, P = 0.032) were independently associated with worse VA in BRAO.

CONCLUSIONS

We found that increased IMT-Bmax, decreased HDL, and female sex were associated with poor VA in BRAO patients. Our findings might suggest novel risk factors for visual dysfunction in BRAO and may provide new insights into the pathomechanisms underlying BRAO.

Relationship between Recurrence of Macular Edema Due to Branch Retinal Vein Occlusion and Changes in Choroidal Thickness

INTRODUCTION

The role of vascular endothelial growth factor in macular edema (ME) due to branch retinal vein occlusion (BRVO) by enhancing vascular permeability has been well studied. ME due to BRVO often recurs; however, there has been no report on the relationship between this recurrence and choroidal thickness (CT), considering the high vascularity of the choroid. This study was designed to investigate this relationship.

METHODS

In this retrospective consecutive case series, patients with recurrence of ME within 6 months of receiving intravitreal aflibercept injection treatment for naive ME due to BRVO at Juntendo University Urayasu Hospital were included. Retinal thickness (RT) and CT were measured in the fovea and on the occlusion, non-occlusion, nasal, and temporal sides at baseline, after the first intravitreal aflibercept administration, and before and after recurrence. We also examined the change for each side before and after reinjection.

RESULTS

This study included 11 patients and 11 eyes. The subfoveal CT and RT at baseline were 261.9 ± 93.4 μm and 691.5 ± 254.4 μm, respectively, which significantly decreased to 208.5 ± 70.3 μm and 188.6 ± 33.8 μm, respectively, at 1 month after the first injection (p = 0.001 and p < 0.01, respectively). These values also significantly decreased at all the other sites after treatment. There were 14 recurrences within the 6 months following intravitreal aflibercept injection; RT significantly changed at all sites before and after recurrence and reinjection. CT significantly changed at the subfovea and on the occlusion and non-occlusion sides; however, there was no significant change on the nasal and temporal sides.

CONCLUSION

In patients with BRVO, the CT around the macula after initial treatment was significantly reduced; however, at the time of ME recurrence and reinjection, there were site-dependent differences in the changes observed in the CT. These findings suggest that the pathologies of ME at initial occurrence and at the time of recurrence are different.

Association of ocular diseases with schizophrenia, bipolar disorder, and major depressive disorder: a retrospective case-control, population-based study

BACKGROUND

Psychiatric disorders and ocular neurovascular diseases may share a similar pathophysiological route of vascular structures or neurological changes. The aim of this study is to investigate the association between ocular neurovascular diseases and the risk of major psychiatric disorders.

METHODS

This was a retrospective case-control, population-based study including patients aged ≥20 and were diagnosed between 1997 and 2013. Ocular neurovascular diseases diagnosed between 1997 and 2006 and newly diagnosed psychiatric disorders including bipolar disorder (BD), major depressive disorder (MDD), and schizophrenia between 2007 and 2013 were registered. Patients were propensity-score matched with control groups without psychiatric disorders in each cohort based on selected covariates.

RESULTS

A total of one million sampled patients in the database were categorized based on their diagnoses; 2243 (37.4% men) were categorized into the BD group, 10,110 (35.2% men) into the MDD group, and 1623 (43.1% men) into the schizophrenia group. In the BD group, all glaucoma (OR 1.49, [1.18-1.89]), open-angle glaucoma (OR 2.08, [1.34-3.24]), and closed-angle glaucoma (OR 2.12, [1.36-3.33]) showed statistical significance of risk. In the MDD group, age-related macular degeneration (OR 1.33, [1.13-1.57]), all glaucoma (OR 1.24, [1.11-1.37]), open-angle glaucoma (OR 1.47, [1.21-1.80]), and dry eye syndrome (OR 1.22, [1.13-1.31]) were associated with a significantly higher risk. In the schizophrenia group, only all glaucoma (OR 1.47, [1.02-2.11]), glaucoma suspect (OR 1.88, [1.01-3.49]), and open-angle glaucoma (OR 2.19, [1.13-4.26]) showed statistical significance.

CONCLUSIONS

In this population-based study, ocular neurovascular diseases, especially glaucoma, were associated with increased risks of BD, MDD, and schizophrenia.

Standard Diffusion-weighted MRI for the Diagnosis of Central Retinal Artery Occlusion

Purpose

To evaluate diffusion abnormalities of the retina and optic nerve in patients with central retinal artery occlusion (CRAO) using standard stroke diffusion-weighted magnetic resonance imaging (DWI).

Methods

In this case-control study, DWI scans of patients with nonarteritic CRAO were retrospectively assessed for acute ischemia of the retina and optic nerve. Two neuroradiologists, blinded for patient diagnosis, randomly evaluated DWI of CRAO patients and controls (a collective of stroke and transient ischemic attack [TIA] patients) for restrictions of the retina and optic nerve. We calculated statistical quality criteria and analyzed inter-rater reliability using unweighted Kappa statistics.

Results

20 CRAO patients (60,6 ± 17 years) and 20 controls (60,7 ± 17 years) were included in the study. Sensitivity, specificity, positive and negative predictive values for retinal DWI restrictions were 75%/80%/79%/76% (reader 1) and 75%/100%/100%/80% (reader 2), respectively. Unweighted Kappa was κ = 0,70 (95% CI 0,48‑0,92), indicating “substantial” interrater reliability. In comparison, sensitivity, specificity, PPV and NPV (positive and negative predictive values) for restrictions of the optic nerve in CRAO were 55%/70%/65%/61% (reader 1) and 25%/100%/100%/57% (reader 2). Inter-rater reliability was “fair” with unweighted Kappa κ = 0,32 (95% CI 0,09‑0,56).

Conclusions

Retinal diffusion restrictions were present in a majority of CRAO patients and detectable with reasonable sensitivity, high specificity and substantial inter-rater reliability. Further studies are necessary to study time dependency of retinal diffusion restrictions, improve image quality and investigate the reliability of retinal DWI to discern CRAO from other causes of acute loss of vision.

Electronic supplementary material

The online version of this article (10.1007/s00062-020-00955-6) contains supplementary material, which is available to authorized users.

Diagnosis of ischemic optic neuropathy caused by dissection of the internal carotid artery: A case report

RATIONALE

Ischemic optic neuropathy (ION), due to diseases of the arteries supplying the optic nerve, is an ischemic damage of the optic nerve. This report highlights a case with monocular decreasing visual acuity caused by dissection of the internal carotid artery (ICA), which is a relatively rare cause for ION.

PATIENT CONCERNS

A 44-year-old woman presented with a decreasing visual acuity and defected visual field in the right eye for 1 week. The best corrected visual acuity (BCVA) was 20/400 in the right eye, and 20/20 in the left eye. In the right eye, the pupil showed little reaction to light with a relative afferent pupillary defect. The visual field test disclosed a defect in the inferior field connecting to the blind spot. Electroretinogram recording showed no obviously declined retinal function. No recognizable waveforms were presented in pattern visual-evoked potential (PVEP) examination, whereas the flash visual-evoked potential result revealed a delayed peak time and a reduced amplitude of P2-wave.

DIAGNOSIS

The patient was diagnosed as ION with the aid of computed tomographic angiography of the brain and neck, which revealed a stenosis in the right ICA and an occlusion in the right cerebral middle artery. The stenosis was verified as dissection of the ICA by digital subtraction angiography.

INTERVENTIONS

Based on the clinical findings, stent implantation inside the right ICA was performed.

OUTCOMES

The ICA was recanalized soon and the BCVA of the right eye was improved to be 20/25 five months later. A second PVEP examination revealed a recognizable waveform in the right eye, although the peak time and amplitude of the P100-wave was a bit abnormal compared to that of the left eye.

LESSONS

ION with the sign of decreasing monocular visual acuity could occur due to dissection of the ICA, with no obvious neurologic symptom at the beginning. The present case emphasizes the importance of suspicion of ICA problems as the underlying cause for ION, which could help to take in-time measure to save the vision and avoid further complications.

Efficacy of Modified Treat-and-Extend Aflibercept Regimen for Macular Edema Due to Branch Retinal Vein Occlusion: 1-Year Prospective Study

PURPOSE

To assess the efficacy and safety of a modified treat-and-extend (mTAE) regimen of aflibercept for macular edema (ME) due to branch retinal vein occlusion (BRVO).

METHODS

This prospective multicentre intervention study evaluated 50 eyes of 50 patients enrolled from October 2016 to September 2017. The patients received intravitreal aflibercept (IVA) injections on an mTAE regimen for a total of 12 months. The main outcome measures were best-corrected visual acuity (BCVA) and central subfield thickness (CST) at 12 months.

RESULTS

The baseline BCVA and CST were 0.33 (0.27) and 488 (171) µm (mean (standard deviation)), respectively. The BCVA and CST were significantly improved at month 12 (0.067 (0.19) LogMAR and 295 (110) µm; both p < 0.0001, paired t-test). The mean number of clinic visits and IVA injections was 6.71 (1.41) and 4.26 (0.71), respectively. The time to first recurrence from the first injection was most frequently 3 months.

CONCLUSION

The mTAE regimen of IVA injections for ME due to BRVO effectively improved BCVA and reduced CST, and thus might be an effective therapy to reduce the number of injections and visits.

Clinical characteristics of branch retinal vein occlusion with increased retinal haemorrhage during treatment for macular oedema

This study was performed to evaluate clinical characteristics of branch retinal vein occlusion (BRVO) patients with increased retinal haemorrhage during macular oedema (MO) treatment. Patients were divided into increased and non-increased retinal haemorrhage groups. The former group was sub-divided based on the degree of increase: < 50% or ≥ 50%. Baseline characteristics, clinical data, and best vision achieved before and after increased retinal haemorrhage were assessed. Sixty-eight eyes of 68 patients were included. Forty-six eyes were non-increased, 11 eyes experienced < 50% increase in retinal haemorrhage, and 11 eyes had ≥ 50% increase. Ischaemic BRVO was related to increased haemorrhage based on the multivariate analysis. The ≥ 50% increase group exhibited higher baseline central subfield macular thickness (CSMT), poorer baseline best corrected visual acuity (BCVA), and longer mean periods between the final intravitreal injections and the time increased retinal haemorrhages were observed, compared to the < 50% group. The best vision achieved before and after increased haemorrhage was significantly worse in the ≥ 50% group. In conclusion, the ischaemic type of BRVO is related to increased retinal haemorrhage during MO treatment, and a ≥ 50% increase in haemorrhages is associated with higher CSMT and poorer BCVA at baseline, with poor visual gain.

Topical Triamcinolone Acetonide-Loaded Liposomes as Primary Therapy for Macular Edema Secondary to Branch Retinal Vein Occlusion: A Pilot Study

Purpose: To explore safety and therapeutic efficacy of a topical ophthalmic triamcinolone acetonide-loaded liposome formulation (TA-LF) as primary therapy in patients with macular edema (ME) secondary to branch retinal vein occlusion (BRVO). Methods: Twelve eyes of 12 patients with ME secondary to BRVO were exposed to a topical instillation of 1 drop of TA-LF (TA 0.2%) 6 times a day for 12 weeks to evaluate safety and efficacy. Best corrected visual acuity (BCVA) intraocular pressure (IOP), slit lamp examination, and central foveal thickness (CFT) were analyzed at every visit. In addition, the morphology of TA-LF was analyzed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Results: Patients presented a significant improvement of BCVA and CFT without significant IOP modification (P = 0.94). Treated eyes showed BCVA improvement from 40 ± 12.05 to 64.83 ± 15.97 letters and CFT reduction from 682.91 ± 278.60 to 271.58 ± 57.66 μm after 12 weeks of TA-LF therapy (P < 0.001). No adverse events, including IOP rising, were registered. SEM analysis of liposomal formulations showed that liposome (LP) size depends on its concentration. As the concentration of TA increased, the average size of LPs and the number of larger particles increased as well. TEM study displayed that LP formulation efficiently solubilizes TA crystals in nanoparticles and encapsulates them. Conclusion: LPs can function as nanocarriers of TA and they could be used as topical ophthalmic primary therapy instead of intravitreal drugs in patients with ME secondary to BRVO.

Spectrum of peripheral retinal ischemia in Wyburn-Mason syndrome

Purpose

We report two cases of Wyburn-Mason syndrome that illustrate the spectrum of peripheral retinal ischemia seen in this condition.

Observations

A 12-year-old female presented with a retinal arteriovenous malformation and sclerotic vessels associated with retinal ischemia on fluorescein angiography, as well as an ipsilateral ophthalmic arteriovenous malformation on magnetic resonance imaging. An 11-year-old male presented with retinal vascular engorgement and tortuosity along with a central retinal vein occlusion and secondary neovascularization.

Conclusions and Importance

Retinal ischemia in Wyburn-Mason syndrome is heterogeneous and may be progressive, with secondary complications that result in neovascularization. Furthermore, it is necessary to recognize that this is a systemic condition that requires neurological evaluation.

Cilioretinal Arteries and Macular Vasculature in Highly Myopic Eyes: An OCT Angiography-Based Study

PURPOSE

To determine the association between the presence of cilioretinal arteries and the macular vasculature in highly myopic eyes using OCT angiography (OCTA).

DESIGN

Retrospective, observational case series.

PARTICIPANTS

Four hundred eighty-one highly myopic eyes of 481 patients.

METHODS

Fundus photographs were reviewed to determine the presence of a cilioretinal artery and its distribution, based on whether its path or visible branches reached the region within 500 μm of the foveal center. The macular vasculature was analyzed in OCTA images, including the vessel density (VD), fractal dimension (FD), and foveal avascular zone (FAZ). The associations between the presence of a cilioretinal artery and its distribution and between the macular vasculature and visual acuity were evaluated.

MAIN OUTCOME MEASURES

Cilioretinal arteries, macular vasculature, and their associations.

RESULTS

Of the eyes included, 17.05% (82/481) had a cilioretinal artery. Based on the OCTA analysis, the eyes with cilioretinal arteries showed significantly higher VD and FD in both superficial and deep capillary plexuses and smaller FAZ than those without (all P < 0.001). However, these differences were not found in the subgroup of eyes with an axial length of more than 30 mm. Eyes with cilioretinal arteries that reached the central foveal area showed significantly higher VD and FD in both capillary plexuses and smaller FAZ than those that did not (all P < 0.05). Better best-corrected visual acuity was identified in the eyes with cilioretinal arteries than in those without (0.09 ± 0.14 logarithm of the minimum angle of resolution [logMAR] vs. 0.21 ± 0.27 logMAR, respectively; P < 0.001). In particular, eyes with cilioretinal arteries that reached the central foveal area had better visual acuity than those without (0.05 ± 0.06 logMAR vs. 0.16 ± 0.20logMAR, respectively; P = 0.005).

CONCLUSIONS

This OCTA-based study suggested that cilioretinal arteries in highly myopic eyes potentially may improve the macular vasculature and influence visual function.

Training in and comfort with diagnosis and management of ophthalmic emergencies among emergency medicine physicians in the United States

Background/objectives

Patients with ophthalmic emergencies often present to emergency rooms. Emergency medicine (EM) physicians should feel comfortable encountering these conditions. We assessed EM physicians’ comfort working up, diagnosing, and managing ophthalmic emergencies.

Subjects/methods

329 EM physicians participated in this cross-sectional multicentre survey. Questions inquired about the amount, type, and self-perceived adequacy of ophthalmic training. Likert scales were used to assess confidence and comfort working up, diagnosing, and managing ophthalmic emergencies.

Results

Participants recall receiving a median of 5 and 10 h of ophthalmic training in medical school and residency, respectively. Few feel this prepared them for residency (16.5%) or practice (52.0%). Only 50.6% feel confident with their ophthalmic exam. Most (75.0%) feel confident in their ability to identify an ophthalmic emergency, but 58.8% feel well prepared to work them up. Responders feel more comfortable diagnosing acute retrobulbar hematoma (72.5%), retinal detachment (69.8%), and acute angle closure glaucoma (78.0%) than central retinal artery occlusion (28.9%) or giant cell arteritis (53.2%). Only 60.2% feel comfortable determining if canthotomy and cantholysis is necessary in the setting of acute retrobulbar hematoma, and 40.3% feel comfortable performing the procedure. There was a trend towards attending physicians and providers in urban and academic settings feeling more comfortable diagnosing and managing ophthalmic emergencies compared to trainees, non-urban, and non-academic physicians.

Conclusions

Many participants do not feel comfortable using ophthalmic equipment, performing an eye exam, making vision or potentially life-saving diagnoses, or performing vision-saving procedures, suggesting the need to increase ophthalmic training in EM curricula.

Angiographic Risk Features of Branch Retinal Vein Occlusion Onset as Determined by Optical Coherence Tomography Angiography

Purpose

Examine associations between the vasculature at arteriovenous (AV) crossings and the onset of branch retinal vein occlusion (BRVO).

Methods

We included 78 patients with major BRVO, 35 patients with macular BRVO, and 110 controls without BRVO and determined the vessel positions at AV crossings, where the first- or second-order branches of the retinal veins associate, using a viewing angle of 12 × 12 mm² in optical coherence tomography angiography (OCTA).

Results

We reviewed 1349 and 1276 AV crossings in BRVO patients and control subjects, respectively. The proportions of venous overcrossing were 26.5%, 28.6%, and 26.8% at non-causative crossings in BRVO eyes, non-BRVO fellow eyes, and unaffected control eyes, respectively; however, the rate of venous overcrossings at the causative crossings was 45.1%. In OCTA analyses, we divided the branches into macular- or non-macular veins. The rate of venous overcrossing was 52.5% at causative crossings in major BRVO but was 28.6% in macular BRVO. Odds ratios for whether venous overcrossing was a risk factor for BRVO were 3.09 (95% confidence interval [CI], 1.96–4.88) and 0.94 (95% CI, 0.44–2.00) for non-macular veins and macular veins, respectively. The patients with major BRVO caused by venous overcrossing were younger than patients for whom the cause was arterial overcrossing (P < 0.001). The onset of macular BRVO did not differ between crossing patterns at causative crossings (P = 0.60).

Conclusions

In eyes with BRVO, venous overcrossing was a common angiographic feature at causative crossings and might be a risk factor for major BRVO onset.

Optical quality assessment in branch retinal vein occlusion after monthly intravitreal ranibizumab injection: a prospective, case-control study

PURPOSE

To evaluate optical quality and intraocular scattering using the Optical Quality Analysis System (OQAS) II in branch retinal vein occlusion (BRVO) and to investigate the influences of retinal changes on optical quality.

MATERIALS AND METHODS

Sixty-two patients with diagnosis of BRVO were enrolled in this prospective, case-control study. The control group consisted of the patients' fellow eyes. Initial logMAR visual acuity, central macular thickness, and optical quality parameters including modulation transfer function cutoff frequency (MTF cut off), Strehl ratio (SR), objective scatter index (OSI) and OQAS values (OVs) at 100%, 20%, and 9% contrast levels were measured. Every BRVO-affected eye was treated with monthly intravitreal ranibizumab injection. We investigated the differences between clinical parameters of the BRVO-affected eye and those of the control eye and changes in those parameters on the basis of the clinical course of BRVO over 3 months.

RESULTS

All the OQAS parameters measured except objective refraction error differed statistically significantly between the two groups. As macular thickness decreased and visual acuity improved, all the optical quality parameters except for objective refraction error and OV at 100% contrast gradually recovered with time after treatment but did not return to normal compared with the control eye. Only visual acuity was found to be significantly related to central macular thickness change (p = .027).

CONCLUSIONS

BRVO resulted in declined visual acuity and optical quality. It is suggested that the optical quality parameters are affected by the inner layers of the retina in BRVO.

Development of visual acuity under hyperbaric oxygen treatment (HBO) in non arteritic retinal branch artery occlusion

PURPOSE

Nonperfusion of retinal tissue due to arterial occlusion leads inevitably to mostly irreversible retinal damage. Until today no evidence-based treatment exists. Inhalation of 100% oxygen at high atmospheric pressure causes an increased solubility of oxygen in the blood that helps the retinal tissue to survive through diffusion in case of an artery occlusion till vascular recanalization occurs. Hence the purpose of this study is to compare the visual outcome in patients with retinal branch artery obstruction treated with hyperbaric oxygen versus patients treated with hemodilution only.

METHODS

Non-randomized, monocentric, retrospective study. Patients with diagnosis of non-arteritic retinal branch artery occlusion (BRAO) treated with hyperbaric oxygen therapy between 1997 and 2017. Exclusion criteria were central retinal artery occlusion, presence of a cilioretinal artery and arteritic cases. The control group was matched based on visual acuity (VA) at admission, age, and delay between symptoms and beginning of clinical care.

RESULTS

The control group and the matching oxygen group contained 14 patients each. Initial VA in the matched HBO group was 0.18 ± 0.19 and 0.23 ± 0.19 in the control group (p = 0.57). Final VA at discharge was 0.69 ± 0.29 in the matched oxygen group and 0.32 ± 0.23 in the control group (p = 0.0009). HBO-treated patients had a significant visual increase compared with the control group. The most common comorbidities were arterial hypertension and vascular sclerosis.

CONCLUSION

HBO treatment appears to have a beneficial effect on visual outcome in patients with retinal branch artery occlusion. HBO treatment could be a rescue therapy at an early stage of BRAO, especially to bridge the time of a potential reperfusion. However, further, prospective, randomized clinical trials are required to verify this assumption.

Retinal artery occlusion does not portend an increased risk of stroke

OBJECTIVE

The aim of this study was to determine the subsequent risk of stroke after a diagnosis of retinal artery occlusion (RAO). We hypothesized that the risk would be low and comparable to that of the general population. RAO is relatively rare and often incorrectly diagnosed. We believe our institution is in a unique position to investigate this relationship with both a high-volume eye center and vascular laboratory.

METHODS

This was a retrospective, single-institution review of 221 patients diagnosed with RAO from 2004 to 2018, confirmed with fluorescein angiography. Demographics, comorbidities, imaging of the carotid arteries, and prospective events, such as stroke, myocardial infarction (MI), and death, were recorded. Time to first stroke, first MI, and death was estimated using Kaplan-Meier estimation separately and as a composite end point.

RESULTS

There were 221 patients identified with a confirmed diagnosis of RAO. The mean age in the cohort was 66.1 years; 53% of patients were male, and 29% were diabetic. Median length of follow-up was 2.2 years. Five patients (2.3%) had a documented stroke; four of the five strokes occurred at the time of RAO, with one that was contralateral occurring at 1.2 years. There were eight MIs (3.6%) in the cohort, two of which resulted in death. Twenty-two patients (10%) experienced a stroke, MI, or death. There were 141 (63.8%) patients who had carotid imaging performed, of whom 20 (14.2%) were found to have >50% stenosis.

CONCLUSIONS

The rate of stroke in patients with confirmed RAO was 2.3%; however, excluding concurrent ischemic events, the risk was <1%. The incidence of carotid artery stenosis >50% was 14.2%. The authors conclude that the risk of stroke after confirmed RAO is lower than previously reported and comparable to prior population-based studies of all at-risk adults.

Thrombophilic risk factors for retinal vein occlusion

The aim is to study risk factors for retinal vein occlusion (RVO), such as thrombophilic and cardiovascular risk factors (CRF). A retrospective consecutive case series of 60 patients with RVO was made, tested for CRF, hyperhomocysteinemia, lupic anticoagulant, antiphospholipid antibody and 5 gene variants: factor V (FV) Leiden (G1691A), factor II (PT G20210A), 5,1-methylenetetra-hydrofolate reductase (MTHFR; 677 C > T and 1298 A > C), plasminogen activator inhibitor 1 (PAI-1; 4 G/5 G). More than 1 CRF were present in 36 patients (60%), which had a significantly higher mean age at diagnosis (66.7 ± 12.9 versus 59.5 ± 13.7 with ≤1 CRF, [t(57) = −2.05, p = 0.045, d = 0.54). Patients with thermolabile MTHFR forms with decreased enzyme activity (T677T or C677T/A1298C) had a significant lower mean age [57.6 ± 15.1; t (58) = 3.32; p = 0.002; d = 0.846] than patients with normal MTHFR enzyme activity (68.5 ± 10.2). Regarding CRF and thermolabile forms of MTHFR, the mean age at diagnosis could be significantly predicted [F(2,56) = 7.18; p = 0.002] by the equation: 64.8 − 10.3 × (thermolabile MTHFR) − 5.31 × ( ≤ 1CRF). Screening of MTHFR polymorphisms may be useful in younger RVO patients, particularly when multiple CRF are absent.

Retina phantom for the evaluation of optical coherence tomography angiography based on microfluidic channels

Optical coherence tomography (OCT) angiography (OCTA) has been actively studied as a noninvasive imaging technology to generate retinal blood vessel network maps for the diagnoses of retinal diseases. Given that the uses of OCT and OCTA have increased in the field of ophthalmology, it is necessary to develop retinal phantoms for clinical OCT for product development, performance evaluation, calibration, certification, medical device licensing, and production processes. We developed a retinal layer-mimicking phantom with microfluidic channels based on microfluidic fabrication technology using polydimethylsiloxane (PDMS) and titanium dioxide (TiO₂) powder. We implemented superficial and deep retinal vessels using microfluidic channels. In addition, multilayered thin films were synthesized with multiple spin-coating processes that comprised layers that corresponded to the retinal layers, including the ganglion cell layer (GCL), inner plexiform layer (IPL), and inner nuclear layer (INL). The phantom was formed by merging the multilayered thin film, and microfluidic channels were assembled with an optical lens, water chamber, and an aluminum tube case. Finally, we obtained cross-sectional OCT images and en-face OCTA images of the retinal phantom using lab-made ophthalmic OCT. From the cross-sectional OCT image, we could compare each of the layer thicknesses of the phantom with the corresponding layer thicknesses of the human retina. In addition, we obtained en-face OCTA images with injections of intralipid solutions. It is shown that this phantom will be able to be potentially used as a convenient tool to evaluate and standardize the quality and accuracy of OCT and OCTA images.

Aldosterone as a mediator of severity in retinal vascular disease: Evidence and potential mechanisms

Diabetic retinopathy (DR) and retinal vein occlusion (RVO) are the two most common retinal vascular diseases and are major causes of vision loss and blindness worldwide. Recent and ongoing development of medical therapies including anti-vascular endothelial growth factor and corticosteroid drugs for treatment of these diseases have greatly improved the care of afflicted patients. However, severe manifestations of retinal vascular disease result in persistent macular edema, progressive retinal ischemia and incomplete visual recovery. Additionally, choroidal vascular diseases including neovascular age-related macular degeneration (NVAMD) and central serous chorioretinopathy (CSCR) cause vision loss for which current treatments are incompletely effective in some cases and highly burdensome in others. In recent years, aldosterone has gained attention as a contributor to the various deleterious effects of retinal and choroidal vascular diseases via a variety of mechanisms in several retinal cell types. The following is a review of the role of aldosterone in retinal and choroidal vascular diseases as well as our current understanding of the mechanisms by which aldosterone mediates these effects.

Multimodal Imaging of Acute Central Retinal Artery Occlusion

The aim of this study was to describe fluorescein angiography (FA), ocular coherence tomography (OCT) and ocular coherence tomography angiography (OCTA) in the diagnosis of acute central retinal artery occlusion (CRAO). This is an observational case series study performed at Sohag Ophthalmic Investigation Center. Fifteen patients presented by a sudden marked unilateral diminution of vision were included. Corrected Distance Visual acuity (CDVA), color fundus photos, FA, OCT and OCTA, imaging obtained in the first week of presentation and imaging of the other normal eye as a control were assessed. Central macular thickness (CMT), parafoveal inner retinal layers thickness and parafoveal outer retinal thickness in diseased and contralateral normal eyes were compared. Fifteen patients (mean age 52.67 years, 11-74 years old) including 66.7% male entered the study. CDVA ranged from no perception of light to 0.05 (20/400). Fundus examination showed a cherry red spot in 10 cases (66.7 %) and retinal whitening in 9 cases (60%), arteriolar narrowing in 7 (46.67%), optic disc edema in 4 (26.67%), optic disc pallor in 5 (33.3%) and cattle trucking in 5 (33.3%). Fluorescein angiography showed delayed arteriovenous transit time > 23 seconds in 8 cases (53.33 %) and normal FA in 4 cases (26.67 %). OCT revealed increased hyperreflective of the inner retinal layers in comparison to hyporeflective inner retinal layers in all cases (100%) and significant increase in CMT in 10 cases (66.67%). The mean ± standard deviation (SD) of CMT (CRAO) was 306.5 ± 27.9 (P < 0.001), the parafoveal inner retinal thickness (CRAO) 345 ± 51.8 µm (P < 0.001) and the parafoveal outer retinal thickness (CRAO) 120.9 ± 13.6 µm (P < 0.001). OCTA was performed and clear images obtained in 11 cases (73.33%). Disruption of superficial and deep capillary plexus was found in all cases. We concluded that the OCT is the most confirmative imaging method in the diagnosis of acute CRAO even in the absence of fundus signs. OCTA confirms the diagnosis, but it cannot be performed in some cases.

Emerging therapies in the management of macular edema: a review

Macular edema (ME) is a major complication of several vascular and inflammatory retinal diseases. Multiple mechanisms are implicated in its development and lead to visual impairment that could be reversible (the acute stages) or not reversible (long-standing ME). For this reason, an effective approach to the treatment of ME is of paramount importance in order to prevent irreversible damage of visual function. In this review, we discuss the management of ME and, in particular, current data of studies and clinical trials about drugs that have already been evaluated or are under investigation in the management of ME. Although several diseases could lead to the development of ME, we focus on the three main causes: diabetic retinopathy (DR), retinal vein occlusion (RVO), and uveitis. The introduction into clinical practice of anti-vascular endothelial growth factor injections (ranibizumab and aflibercept) and dexamethasone implants has revolutionized the treatment of ME secondary to DR and RVO. However, new drugs are needed in the treatment of resistant forms of ME secondary to DR and RVO. A fluocinolone acetonide implant has been approved by the US Food and Drug Administration for the treatment of diabetic ME but not for RVO. Furthermore, brolucizumab and abicipar pegol have been shown to be effective in preliminary studies and have the chance to be approved soon for diabetic ME treatment. In ME secondary to uveitis, a crucial role is played by corticosteroids and non-biologic immunomodulatory drugs. However, several new biologic agents are under investigation in different clinical trials and could be important new therapeutic options in cases with a low response to first-line therapy. However, only a few of these drugs will enter the market after proving their safety and efficacy. Only after that will we be able to offer a new therapeutic option to patients affected by uveitic ME.

Arteriovenous crossing associated with branch retinal vein occlusion

Branch retinal vein occlusion (BRVO) is defined as the focal occlusion of a first or second-order branch of retinal vein, which occurs most frequently at an arteriovenous (AV) crossing. Direct ophthalmoscopy, color fundus photography, and fluorescein angiography facilitate observation of AV crossings parallel to the retinal plane. Optical coherence tomography (OCT), with its high-depth resolution, enables observation of retinal lesions perpendicular to the retinal plane. OCT angiography (OCTA) provides depth-resolved images of the retinal vasculature by segmenting three-dimensional data. In this review, we discuss novel findings related to affected AV crossings associated with BRVO obtained via OCT and OCTA. The high-depth resolution of OCT or OCTA is useful for observation of the narrowed vein and determination of the vessel position of the affected AV crossing. Studies using OCT and OCTA have shown that BRVO caused by a venous overcrossing is more prevalent than previously reported, and that venous narrowing was significantly greater in instances caused by a venous overcrossing than in those caused by an arterial overcrossing. Moreover, OCTA also revealed that the retinal nonperfusion area size was larger in eyes with BRVO caused by a venous overcrossing than in those with BRVO caused by an arterial overcrossing. This contrasts with earlier findings obtained by conventional imaging modalities predating OCT, which showed that an arterial overcrossing was more common than a venous overcrossing at the causative venous occlusion site in eyes with BRVO. This review discusses these findings and their significance in the study of AV crossing associated with BRVO.

Comparison of systemic conditions at diagnosis between central retinal vein occlusion and branch retinal vein occlusion

Objective

To compare systemic conditions at the time of diagnosis between patients with central retinal vein occlusion (CRVO) and branch retinal vein occlusion (BRVO).

Design

This study included patients diagnosed with CRVO or BRVO between February 2009 and August 2017 at three branch hospitals of Hallym University Medical Center. Demographic and anthropometric variables, systemic comorbidity profiles, and laboratory findings at diagnosis were collected from a clinical data warehouse system, and were compared between the CRVO and BRVO groups.

Result

Four hundred and seventeen patients with CRVO and 1,511 patients with BRVO were included. The mean age was 61.8 ± 13.9 years, which was comparable between two groups (P = .332). Female proportion was higher in the BRVO group (55.0%) than in the CRVO group (48.0%; P = .013). Diabetes mellitus (P = .017) and chronic kidney disease (P = .004) were more prevalent in the CRVO group. Serum homocysteine level was abnormally high in 23.5% of CRVO patients and in 8.4% of BRVO patients (P < .001). Blood urea nitrogen and serum creatinine levels were abnormally elevated in more subjects with CRVO (P = .002).

Conclusion

CRVO is associated with higher prevalence of diabetes mellitus and chronic kidney disease, as well as with elevated serum homocysteine level. These results might suggest a difference between the pathophysiologies of CRVO and BRVO.

High-resolution multimodal photoacoustic microscopy and optical coherence tomography image-guided laser induced branch retinal vein occlusion in living rabbits

Joint high-resolution multimodal photoacoustic microscopy (PAM) and optical coherence tomography (OCT) was developed to improve the efficiency for visualizing newly developed retinal neovascularization (RNV) and to monitor the dynamic changes of retinal vein occlusion (RVO) in living rabbits. The RNV and RVO models were created in New Zealand rabbits by Rose Bengal laser-induced RVO. Dual modalities imaging equipment, including color fundus photography, fluorescein angiography (FA), OCT, and PAM, was used to image and assess the changes of retinal vasculature. In vivo experimental results exhibited that not only the treatment boundaries and the position of the occluded vasculature but also the structure of individual RNV were markedly observed using PAM platform with great resolution and high image contrast. The laser light energy of 80 nJ was used to induce photoacoustic signal, which is approximately half the energy of the American National Standards Institute safety limit. A cross-sectional structure of RNV was identified with the OCT modality. Furthermore, vibrant transformations in the RNV and the retinal morphology were examined at different times after laser occlusion: days 4, 28, 35, 49, and 90. PAM revealed high contrast and high resolution vascular imaging of the retina and choroid with amplified penetration depth. Through the present custom-built imaging system, both RNV and RVO can be reconstructed and observed in two and three dimensions. A unique dual modality A unique dual modality PAM and OCT can help precisely visualize and distinguish individual microvessels, microvessel depth, and the surrounding anatomy. Thus, the proposed multimodal ocular imaging platform may offer a potential equipment to enhance classification of microvasculature in a reliable and proficient manner in larger rabbit eyes.

Intravitreal Medications for Retinal Vein Occlusion: Systematic Review and Meta-analysis

Purpose

To evaluate the outcomes of different intravitreal injections for the treatment of retinal vein occlusion including central retinal vein occlusion (CRVO) and branch retinal vein occlusion (BRVO).

Methods

PubMed, Cochrane, the metaRegister of ControlledTrials, and ClinicalTrials were searched for intravitreal anti-Vascular Endothelial Growth Factor (VEGF) and steroids with relevant keywords and date limitation of 2009-2018. Meta-analysis was performed on studies that met the defined inclusion criteria. Main outcomes were visual acuity (VA) and central macular thickness (CMT).

Results

Out of 681 studies, 36 articles (including 21 reporting CRVO and 15 dealing with BRVO) were selected for systematic review. All five intravitreal drugs including triamcinolone, dexamethasone, ranibizumab, bevacizumab, and aflibercept showed improvement of CMT and VA as compared to placebo or laser treatment. Six randomized controlled trials were selected for meta-analysis in RVO patients. The pooled mean difference of visual improvement between sham and ranibizumab was 12.7 Early Treatment for Diabetic Retinopathy Study (ETDRS) letters (95%CI: 11.00 to 13.2), and the pooled mean difference in CMT reduction was 221μm (95%CI: 153 to 284); both changes were significantly in favor of ranibizumab. The pooled mean difference of visual improvement between bevacizumab and triamcinolone was 5.3 ETDRS letters in favor of bevacizumab (95%CI: 16 μm to 17.5 μm). Triamcinolone led to 68.1 μm greater CMT reduction than bevacizumab (95%CI: 58 μm to 76 μm). However, none of these differences were statistically significant.

Conclusion

Treatment with anti-VEGF agents in RVO is superior to observation. No significant difference was seen between the eyes treated with bevacizumab or triamcinolone based on these results.

Intravenous Prostaglandin E1 Infusion for Acute Central Retinal Artery Occlusion

BACKGROUND AND OBJECTIVE

To evaluate the efficacy of systemic prostaglandin E1 (PGE1) infusion within the first 24 hours of acute central retinal artery occlusion (CRAO).

PATIENTS AND METHODS

Best corrected visual acuity (BCVA) was analyzed in a case series of six eyes from six patients (mean age: 69.33 years) with acute CRAO who were treated with twice-daily intravenous infusion of 40 μg PGE1. Therapy continued until the patient no longer experienced visual acuity improvements for 24 hours.

RESULTS

Average time to presentation was 8.33 hours (range: 2 to 12 hours). The logMAR BCVA at presentation was 2.73. BCVA at the final visit 1 month after initial presentation was 1.48 (P = .025). All patients experienced vision improvement. No systemic adverse events were experienced.

CONCLUSION

Intravenous PGE1 infusion resulted in significant visual improvement in patients presenting with acute CRAO and is well tolerated with few adverse effects. [Ophthalmic Surg Lasers Imaging Retina. 2019;50:S5-S8.].

Branch Retinal Vein Occlusion: Treatment Outcomes According to the Retinal Nonperfusion Area, Clinical Subtype, and Crossing Pattern

This prospective study examined 58 eyes with branch retinal vein occlusion (BRVO) to investigate the effects of the nonperfusion area (NPA), clinical subtype, and crossing pattern on the 2-year outcomes of ranibizumab therapy for the macular edema (ME). All eyes received three initial monthly injections, followed by additional pro re nata (PRN) injections. The final best corrected visual acuity (BCVA) and ranibizumab injection number were not associated with the macular NPA or total NPA at baseline or month 12, and they showed no significant differences between the clinical subtypes. However, the incidence of neovascular changes was higher in the major BRVO group than in the macular BRVO group (P = 0.030). Twelve and 19 of the 34 eyes with major BRVO exhibited arterial overcrossing and venous overcrossing, respectively. At baseline, the total NPA did not differ according to the crossing pattern, however, the total NPA was significantly larger in the venous overcrossing group at month 12 (P = 0.047). At month 24, the incidence of neovascular changes was higher in the venous overcrossing group (P = 0.030). Following ranibizumab therapy for BRVO-associated ME, the clinical subtype and the arteriovenous crossing pattern may be associated with neovascular changes.

Intravitreal dexamethasone implant for central retinal vein occlusion without macular edema

Background

To evaluate the efficacy of an intravitreal dexamethasone (IVD) implant (Ozurdex®) for the treatment of central retinal vein occlusion (CRVO) without macular edema (ME).

Methods

A retrospective cohort study was designed, and 20 eyes of 20 patients diagnosed with non-ischemic CRVO without ME were included. A total of 10 CRVO eyes were observed without treatment, and another 10 CRVO eyes received a single IVD injection at baseline. Mean changes in pathomorphologic parameters of fundus and optical coherence tomography parameters were measured at baseline and at 1, 3, 6, and 12 months.

Results

The decreases in venous tortuosity (p = 0.014 for superior; 0.036 for inferior arcades) and width (p = 0.024 for superior; 0.003 for inferior arcades) from baseline to 12 months after injection were significantly greater in the treated group than the observed group. The improvements in RNFL swelling (p = 0.010) and retinal hemorrhage (p = 0.006) were also significantly greater in the treated group. Visual symptom improvement was significantly faster in the treated group (p = 0.001). In two cases, IVD injection resulted in complete resolution of cilioretinal artery occlusion associated with the CRVO, leading to complete visual recovery in 1 week. None of the treated eyes showed signs of ME development, ischemia progression, or neovascularization.

Conclusions

IVD implant was significantly effective in improving venous engorgement, retinal hemorrhage, RNFL swelling, and visual symptoms by presumed alleviation of disc swelling and venous outflow. This treatment may be a considerable treatment option in CRVO patients with no ME.

Five-year outcomes of retinal vein occlusion treated with vascular endothelial growth factor inhibitors

Purpose

Report 5-year outcomes of patients receiving anti-vascular endothelial growth factor (VEGF) for the treatment of macular oedema secondary to retinal vein occlusion (RVO.

Methods

Retrospective review of eyes with RVO which initiated anti-VEGF treatment. Data including age, gender, visual acuity (VA) and injection numbers were obtained from medical records. Optical coherence tomography scans were graded for presence or absence of macular oedema and central foveal thickness (CFT). Macular perfusion was assessed on fundus fluorescein angiography by masked graders.

Results

68 eyes (31 branch RVO, BRVO; 35 central RVO, CRVO and 2 hemi-RVO) with 5 years of follow-up after initiation of anti-VEGF treatment. Mean change in VA at 5 years was + 9.6 ± 21.6 letters among CRVO eyes and + 14.2 ± 15.6 letters among eyes with BRVO (p=0.001). Vision of 20/40 or better was achieved in 65 % of treated eyes. The proportion of eyes with a three-line improvement of vision (15 letters) at 5 years was 22 %. Mean CFT decreased by 257.6 ± 249.8 µm in eyes with CRVO and 145.6 ± 143.3 µm in eyes with BRVO.

Conclusion

The results confirm good long-term outcomes can be achieved with anti-VEGF therapy for RVO.

Delayed Vision Recovery after Carotid Vascular Surgery for Branch Retinal Artery Occlusion

Branch retinal artery occlusion (BRAO) is typically associated with irreversible vision and peripheral visual field loss. We report a case of a 62-year-old woman with a BRAO related to several cardiovascular risk factors. Our patient encountered gradual but significant vision recovery months following carotid artery endarterectomy for carotid stenosis.

Aspirin use in central retinal arterial occlusion to prevent ischaemic stroke: a retrospective cohort study in Taiwan

OBJECTIVE

To understand the efficacy of aspirin use for preventing ischaemic stroke after central retinal artery occlusion (CRAO).

DESIGN

The retrospective cohort study was conducted using the National Health Insurance Research Database from 1998 to 2013.

SETTING

A population-based study.

PARTICIPANTS

A total of 9437 participants with newly diagnosed CRAO were identified. Participants who had a previous stroke and/or retinal vascular occlusion, were aged <20 years and used aspirin 3 months before the event were excluded. There were 3778 eligible participants matched by propensity score, and they were divided into aspirin (n=434) and aspirin-naive (n=1736) groups after the matching.

METHODS

Cox proportional hazard models and cumulative survival curves were used to assess ischaemic stroke in the study groups, along with log-rank tests to compare group differences.

MAIN OUTCOME MEASURES

Incidence of ischaemic stroke in the aspirin and aspirin-naive groups 1 year after CRAO.

RESULTS

Of the 3778 patients with newly diagnosed CRAO, 151 (4%) had a subsequent ischaemic stroke within 1 year. The risk was especially high during the first week of the CRAO. No difference between the aspirin and aspirin-naive groups was found in risk of ischaemic stroke, haemorrhagic stroke, gastrointestinal bleeding, major bleeding, acute coronary syndrome, retinal vein occlusion, new-onset glaucoma, undergoing panretinal photocoagulation or all-cause mortality. Risk factors for ischaemic stroke within 1 year of CRAO included male gender (p=0.031; HR=1.46) and age (p=0.032; HR=1.14).

CONCLUSIONS

Aspirin use after a CRAO showed no benefit on attenuating the risk of ischaemic stroke. The risk of ischaemic stroke was increased after CRAO especially during the first week. Male gender and age were risk factors for ischaemic stroke after CRAO.

Complement Factor H Mutation W1206R Causes Retinal Thrombosis and Ischemic Retinopathy in Mice

Single-nucleotide polymorphisms and rare mutations in factor H (FH; official name, CFH) are associated with age-related macular degeneration and atypical hemolytic uremic syndrome, a form of thrombotic microangiopathy. Mice with the FH W1206R mutation (FH^R/R) share features with human atypical hemolytic uremic syndrome. Herein, we report that FH^R/R mice exhibited retinal vascular occlusion and ischemia. Retinal fluorescein angiography demonstrated delayed perfusion and vascular leakage in FH^R/R mice. Optical coherence tomography imaging of FH^R/R mice showed retinal degeneration, edema, and detachment. Histologic analysis of FH^R/R mice revealed retinal thinning, vessel occlusion, as well as degeneration of photoreceptors and retinal pigment epithelium. Immunofluorescence showed albumin leakage from blood vessels into the neural retina, and electron microscopy demonstrated vascular endothelial cell irregularity with narrowing of retinal and choroidal vessels. Knockout of C6, a component of the membrane attack complex, prevented the aforementioned retinal phenotype in FH^R/R mice, consistent with membrane attack complex-mediated pathogenesis. Pharmacologic blockade of C5 also rescued retinas of FH^R/R mice. This FH^R/R mouse strain represents a model for retinal vascular occlusive disorders and ischemic retinopathy. The results suggest complement dysregulation can contribute to retinal vascular occlusion and that an anti-C5 antibody might be helpful for C5-mediated thrombotic retinal diseases.

In Vivo 3D Imaging of Retinal Neovascularization Using Multimodal Photoacoustic Microscopy and Optical Coherence Tomography Imaging

The pathological process of neovascularization of the retina plays a critical role in causing vision loss in several diseases, including diabetes, retinal vein occlusion, and sickle cell disease. Retinal neovascularization can lead to vitreous hemorrhage and retinal detachment, yet the pathological process of neovascularization is a complex phenomenon under active investigation. Understanding and monitoring retinal neovascularization is critically important in clinical ophthalmology. This study describes a novel multimodal ocular imaging system which combines photoacoustic microscopy (PAM) and a spectral domain optical coherence tomography (SD-OCT) to improve the visualization of retinal neovascularization (RNV), their depth, and the surrounding anatomy in living rabbits. RNV was induced in New Zealand rabbits by intravitreal injection of vascular endothelial growth factor (VEGF). The retinal vasculature before and after injection at various times was monitored and evaluated using multimodal imaging including color fundus photography, fluorescein angiography (FA), OCT, and PAM. In vivo experiments demonstrate that PAM imaging distinctly characterized the location as well as the morphology of individual RNV with high contrast at a safe laser energy of 80 nJ. SD-OCT was used to identify a cross-sectional structure of RNV. In addition, dynamic changes in the retinal morphology and retinal neovascularization were observed at day 4, 5, 6, 7, 9, 11, 14, 28, and day 35 after VEGF injection. PAM demonstrated high-resolution optical absorption of hemoglobin and vascular imaging of the retina and choroid with increased depth of penetration. With the current multimodal imaging system, RNV can be easily visualized in both 2D and 3D angiography. This multimodal ocular imaging system provides improved characterization of the microvasculature in a safe manner in larger rabbit eyes.

Multi-wavelength, en-face photoacoustic microscopy and optical coherence tomography imaging for early and selective detection of laser induced retinal vein occlusion

Multi-wavelength en face photoacoustic microscopy (PAM) was integrated with a spectral domain optical coherence tomography (SD-OCT) to evaluate optical properties of retinal vein occlusion (RVO) and retinal neovascularization (RNV) in living rabbits. The multi-wavelength PAM of the RVO and RNV were performed at several wavelengths ranging from 510 to 600 nm. Rose Bengal-induced RVO and RNV were performed and evaluated on eight rabbits using color fundus photography, fluorescein angiography, OCT, and spectroscopic en face PAM. In vivo experiment demonstrates that the spectral variation of photoacoustic response was achieved. The location and the treatment margins of the occluded vasculature as well as the morphology of individual RNV were obtained with high contrast at a laser energy of 80 nJ, which was only half of the American National Standards Institute safety limit. In addition, dynamic changes in the retinal morphology and retinal neovascularization were administered using PA spectroscopy at numerous time points: 0, 3, 7, 14, 21, 28, and 35 days after photocoagulation. The proposed multi-wavelength spectroscopic PAM imaging may provide a potential imaging platform to differentiate occluded retinal vasculature and to improve characterization of microvasculature in a safe and efficient manner.

Retinal oximetry and systemic arterial oxygen levels

PURPOSE

Continuous peripheral pulse oximetry for monitoring adequacy of oxygenation is probably the most important technological advance for patients' monitoring and safety in the last decades. Pulse oximetry has the disadvantage of measuring the peripheral circulation, and the only mean to measure oxygen content of the central circulation is by invasive technology. Determination of blood oxyhaemoglobin saturation in the retinal vessels of the eye can be achieved noninvasively through spectrophotometric retinal oximetry which provides access to the central nervous system circulation. The aim of the thesis was to determine whether retinal oximetry technique can be applied for estimation of the central nervous system circulation which until now has only been possible invasively. This was achieved by measuring oxyhaemoglobin saturation in three adult subject study groups: in people with central retinal vein occlusion (CRVO) to observe local tissue hypoxia, in patients with severe chronic obstructive pulmonary disease (COPD) on long-term oxygen therapy to observe systemic hypoxaemia and in healthy subjects during hyperoxic breathing to observe systemic hyperoxemia. In addition, the fourth study that is mentioned was performed to test whether retinal oximetry is feasible for neonates.

METHODS

Retinal oximetry in central retinal vein occlusion: Sixteen subjects with central retinal vein occlusion participated in the study. The oxyhaemoglobin saturation of the central retinal vein occlusion affected eye was compared with the fellow unaffected eye. Retinal oximetry in healthy people under hyperoxia: Thirty healthy subjects participated in the study, and the oxyhaemoglobin saturation of retinal arterioles and venules was compared between normoxic and hyperoxic breathing. Retinal oximetry in severe chronic obstructive pulmonary disease: Eleven patients with severe chronic obstructive pulmonary disease participated in the study. Retinal oximetry measurements were made with and without their daily supplemental oxygen therapy. Retinal arteriolar oxyhaemoglobin saturation when inspiring ambient air was compared with blood samples from the radial artery and finger pulse oximetry and healthy controls. The healthy control group was assembled from our database for comparison of oxyhaemoglobin saturation of retinal arterioles and venules during the ambient air breathing. The retinal oximeter is based on a conventional fundus camera and a specialized software. A beam splitter coupled with two high-resolution digital cameras allows for simultaneous acquisition of retinal images at separative wavelengths for calculation of oxyhaemoglobin saturation. In addition, retinal images of 28 full-term healthy neonates were obtained with scanning laser ophthalmoscope combined with modified Oxymap analysis software for calculation of the optical density ratio and vessel diameter RESULTS: Retinal oximetry in central retinal vein occlusion: Mean retinal venous oxyhaemoglobin saturation was 31 ± 12% in CRVO eyes and 52 ± 11% in unaffected fellow eyes (mean ± SD, n = 14, p < 0.0001). The arteriovenous oxygen difference (AV-difference) was 63 ± 11% in CRVO eyes and 43 ± 7% in fellow eyes (p < 0.0001). The variability of retinal venous oxyhaemoglobin saturation was considerable within and between eyes affected by CRVO. There was no difference in oxyhaemoglobin saturation of retinal arterioles between the CRVO eyes and the unaffected eyes (p = 0.49). Retinal oximetry in healthy people under hyperoxia: During hyperoxic breathing, the oxyhaemoglobin saturation in retinal arterioles increased to 94.5 ± 3.8% as compared with 92.0 ± 3.7% at baseline (n = 30, p < 0.0001). In venules, the mean oxyhaemoglobin saturation increased to 76.2 ± 8.0% from 51.3 ± 5.6% (p < 0.0001) at baseline. The AV-difference was markedly lower during hyperoxic breathing as compared with the normoxic breathing (18.3 ± 9.0% versus 40.7 ± 5.7%, p < 0.0001). Retinal oximetry in severe chronic obstructive pulmonary disease: During ambient air breathing, chronic obstructive pulmonary disease subjects had significantly lower oxyhaemoglobin saturation than healthy controls in both retinal arterioles (87.2 ± 4.9% versus 93.4 ± 4.3%, p = 0.02, n = 11) and venules (45.0 ± 10.3% versus 55.2 ± 5.5%, p = 0.01) but the AV-difference was not markedly different (p = 0.17). Administration of their prescribed oxygen therapy significantly increased the oxyhaemoglobin saturation in retinal arterioles (87.2 ± 4.9% to 89.5 ± 6.0%, p = 0.02) but not in venules (45.0 ± 10.3% to 46.7 ± 12.8%, p = 0.3). Retinal oximetry values were slightly lower than finger pulse oximetry (mean percentage points difference = -3.1 ± 5.5) and radial artery blood values (-5.0 ± 5.4). Retinal oximetry study in neonates: The modified version of the retinal oximetry instrument estimated the optical density ratio in retinal arterioles to be 0.256 ± 0.041 that was significantly different from the 0.421 ± 0.089 in venules (n = 28, p < 0.001, paired t-test). The vascular diameter of retinal arterioles was markedly narrower than of venules (14.1 ± 2.7 and 19.7 ± 3.7 pixels, p < 0.001).

CONCLUSION

The results of this thesis indicate that spectrophotometric retinal oximetry is sensitive to both local and systemic changes in oxyhaemoglobin saturation. Retinal oxyhaemoglobin saturation values are slightly lower than radial artery blood sample and finger pulse oximetry values. The discrepancies between the different modalities are expected to derive from countercurrent exchange between central retinal artery and vein within the optic nerve but calibration issues cannot be excluded as contributing to this difference. Despite these differences, the findings indicate the potential of retinal oximetry for noninvasive real-time measurements of oxyhaemoglobin saturation in central nervous system vessels. Following calibration upgrade and technological improvement, verification retinal oximetry may potentially be applied to critically ill and anaesthesia care patients. The study on combined scanning laser ophthalmoscope and retinal oximetry supports the feasibility of the technique for oximetry analysis in newly born babies.

IL-18 and S100A12 Are Upregulated in Experimental Central Retinal Vein Occlusion

Retinal vein occlusion (RVO) is a common retinal vascular disease. RVO may be complicated by pronounced ischemia that often leads to severe loss of visual function. The present work aimed at studying the retinal proteome of RVO complicated by ischemia. In six Danish Landrace pigs RVO was induced with argon laser in the right eye of each animal. As four retinal veins were occluded, the RVO best corresponded to a central retinal vein occlusion (CRVO). Left control eyes received a similar laser treatment without inducing occlusion. RVO and retinal ischemia were verified by angiography. The retinas were collected 15 days after RVO for proteomic analysis. RVO resulted in a downregulation of proteins involved in visual perception, including rhodopsin, transducin alpha chain, and peripherin-2. RVO also caused a downregulation of proteins involved in neurotransmitter transport, including glutamate decarboxylase 1 (GAD1), glutamate decarboxylase 2 (GAD2), and complexins 2⁻4. RVO lead to increased contents of proteins involved in inflammation, including interleukin-18 (IL-18), S100A12, and annexin A1 (ANXA1). Immunohistochemistry revealed a general retinal upregulation of IL-18 and ANXA1 while S100A12 was highly abundant in retinal ganglion cells in RVO. IL-18 and S100A12 are likely to be driving forces in the inflammatory response of RVO complicated by ischemia. Our findings also suggest that RVO results in compromised neurotransmission and a downregulation of proteins involved in visual perception.

Cilioretinal artery hypoperfusion and its association with paracentral acute middle maculopathy

BACKGROUND/AIMS

To study the multimodal imaging findings of a large series of eyes with cilioretinal artery obstruction (CILRAO) and describe the systemic associations.

METHODS

Multicentre, retrospective chart review from 12 different retina clinics worldwide of eyes with CILRAO, defined as acute retinal whitening in the distribution of the cilioretinal artery, were identified. The clinical, systemic information and multimodal retinal imaging findings were collected and analysed.

RESULTS

A total of 53 eyes of 53 patients with CILRAO were included in the study. In 100% of eyes, fundus photography illustrated deep retinal whitening corresponding to the course of the cilioretinal artery. Twenty-eight patients (52.8%) presented with isolated CILRAO (baseline best-corrected visual acuity (BCVA) 20/50, final BCVA 20/25) associated with nocturnal hypotension, 23 patients (43.4%) with CILRAO secondary to central retinal vein occlusion (CRVO) (baseline BCVA 20/40, final BCVA 20/20) and two patients with CILRAO due to biopsy-proven giant cell arteritis (GCA) (baseline BCVA 20/175, final BCVA 20/75). With spectral domain optical coherence tomography (SD-OCT), a hyper-reflective band involving the inner nuclear layer (ie, paracentral acute middle maculopathy or PAMM) was noted in 51 eyes (28/28 eyes with isolated CILRAO and 23/23 eyes with CILRAO+CRVO) corresponding to the retinal whitening. In the two eyes with CILRAO+GCA, SD-OCT illustrated hyper-reflective ischaemia of both the middle and inner retina.

CONCLUSIONS

Isolated CILRAO and CILRAO secondary to CRVO are the result of hypoperfusion or insufficiency, rather than occlusion, of the cilioretinal artery and are associated with PAMM or selective infarction of the the inner nuclear layer. With GCA, there is complete occlusion of the cilioretinal artery producing ischaemia involving both the middle and inner retina associated with worse visual outcomes.

Persistent metamorphopsia associated with branch retinal vein occlusion

Purpose

To investigate longitudinal changes in metamorphopsia associated with branch retinal vein occlusion.

Methods

In this prospective observational case series, we included 32 eyes (32 patients) with branch retinal vein occlusion and acute macular edema. Eyes were treated as needed with intravitreal ranibizumab injections for 12 months. At baseline and 1, 6, and 12 months after initiating treatment, metamorphopsia was quantified using M-CHARTS. Retinal morphology was examined through optical coherence tomography.

Results

Logarithm of the minimum angle of resolution visual acuity progressively improved from 0.342 ± 0.304 (Snellen equivalent: 20/44) at baseline to 0.199 ± 0.259 (20/32) and 0.118 ± 0.195 (20/26) at 1 and 12 months, respectively (both P < 0.001). The M-CHARTS score significantly decreased from 0.63 ± 0.61 at baseline to 0.45 ± 0.50 at 1 month (P = 0.044), but no further improvement was achieved with 1 year of additional treatment (6 months: 0.47 ± 0.53 [P = 0.094] and 12 months: 0.50 ± 0.44 [P = 0.173]). Three (13.6%) of 22 eyes with baseline metamorphopsia had complete metamorphopsia resolution. At 12 months, the M-CHARTS score was correlated with baseline foveal thickness (r = 0.373, P = 0.035) and the baseline M-CHARTS score (r = 0.503, P = 0.003). A multiple regression analysis revealed that only the baseline M-CHARTS score was correlated with the 12-month M-CHARTS score (β = 0.460, P = 0.027).

Conclusions

Eyes with branch retinal vein occlusion often have persistent metamorphopsia, even when visual acuity and retinal morphology improve. Metamorphopsia at 12 months was correlated with metamorphopsia and foveal thickness at baseline.

Comparison of one and three initial monthly intravitreal ranibizumab injection in patients with macular edema secondary to branch retinal vein occlusion

AIM

To compare three initial monthly intravitreal ranibizumab (IVR) injections followed by pro re nata (PRN) dosing with one initial monthly IVR injections followed by PRN dosing for macular edema (ME) secondary to branch retinal vein occlusion (BRVO).

METHODS

Forty-two eyes of 42 patients who had IVR injections for BRVO were retrospectively studied. Eighteen eyes received 1 initial IVR injection (1+PRN group) and 24 eyes received 3 monthly IVR injections (3+PRN). At 1, 3, 6 and 12mo; spectral-domain optical coherence tomography (SD-OCT) was performed. Central macular thickness (CMT), the integrity of the external limiting membrane (ELM), the presence of subretinal fluid, cyst size, the presence of inner segment/outer segment (IS/OS) defect were determined.

RESULTS

At baseline the mean CMT was 521.3±153.2 µm in the 3+PRN group while it was 438.1±162.4 µm in 1+PRN group. At the final visit, mean CMT was 278.3±87.8 µm in the 3+PRN group and 285.2±74.2 µm in the 1+PRN group (P=0.079). The changes in CMT over the entire study period were also comparable in both groups (243±160 µm in the 3+PRN group, and 152.9±175.3 µm in the 1+PRN group; P=0.090). At baseline, best-corrected visual acuity (BCVA) was 0.92±0.60 logarithm of the minimal angle of resolution (logMAR) in the 3+PRN group, while it was 0.72±0.46 logMAR in the 1+PRN group. Final BCVA was 0.42±0.55 logMAR in the 3+PRN group and 0.38±0.50 logMAR in the 1+PRN group (P=0.979). Additionally, the BCVA changes from baseline to final visit were not significantly different (-0.50±0.45 logMAR in the 3+PRN group, and -0.33±0.39 logMAR in the 1+PRN group; P=0.255).

CONCLUSION

No significant differences in the anatomical or functional results are found between 3+PRN and 1+PRN regimens in the patients receiving ranibizumab for ME secondary to BRVO. Intact IS/OS and baseline BCVA are good predictor of the visual gain, while baseline CMT is a good predictor of the anatomical gain.

Review of clinical approaches in fluorescence lifetime imaging ophthalmoscopy

Autofluorescence-based imaging techniques have become very important in the ophthalmological field. Being noninvasive and very sensitive, they are broadly used in clinical routines. Conventional autofluorescence intensity imaging is largely influenced by the strong fluorescence of lipofuscin, a fluorophore that can be found at the level of the retinal pigment epithelium. However, different endogenous retinal fluorophores can be altered in various diseases. Fluorescence lifetime imaging ophthalmoscopy (FLIO) is an imaging modality to investigate the autofluorescence of the human fundus in vivo. It expands the level of information, as an addition to investigating the fluorescence intensity, and autofluorescence lifetimes are captured. The Heidelberg Engineering Spectralis-based fluorescence lifetime imaging ophthalmoscope is used to investigate a 30-deg retinal field centered at the fovea. It detects FAF decays in short [498 to 560 nm, short spectral channel (SSC) and long (560 to 720 nm, long spectral channel (LSC)] spectral channels, the mean fluorescence lifetimes (τm) are calculated using bi- or triexponential approaches. These are meant to be relatively independent of the fluorophore's intensity; therefore, fluorophores with less intense fluorescence can be detected. As an example, FLIO detects the fluorescence of macular pigment, retinal carotenoids that help protect the human fundus from light damages. Furthermore, FLIO is able to detect changes related to various retinal diseases, such as age-related macular degeneration, albinism, Alzheimer's disease, diabetic retinopathy, macular telangiectasia type 2, retinitis pigmentosa, and Stargardt disease. Some of these changes can already be found in healthy eyes and may indicate a risk to developing such diseases. Other changes in already affected eyes seem to indicate disease progression. This review article focuses on providing detailed information on the clinical findings of FLIO. This technique detects not only structural changes at very early stages but also metabolic and disease-related alterations. Therefore, it is a very promising tool that might soon be used for early diagnostics.

Six-month results of intravitreal ranibizumab for macular edema after branch retinal vein occlusion in a single-center prospective study: visual outcomes and microaneurysm formation

Purpose

The aim of this study is to report the 6-month results after one intravitreal ranibizumab (IVR) injection followed by pro re nata dosing for macular edema (ME) after branch retinal vein occlusion.

Patients and methods

The inclusion criteria included a minimal patient age of 18 years, 20 letters or more best-corrected visual acuity (BCVA) (Early Treatment Diabetic Retinopathy Study [ETDRS] score, 77 letters or less), and central retinal thickness (CRT) of 250 microns or more. The primary outcome measure was the mean BCVA change from baseline at month 6; the secondary outcomes were mean changes in CRT, residual ME, and microaneurysm formation.

Results

Twenty patients were enrolled from March 2014 through October 2016 at Nagoya City University Hospital. The baseline mean ETDRS letters and CRT were 63.1 and 500 microns, respectively; mean time from symptom onset to initial therapy was 1.80 months; and mean ETDRS gain and CRT reduction were 15.2 letters and 230 microns, respectively. The percentages of patients with Snellen equivalent BCVAs of 20/40 (70 ETDRS letters) or better and 20/20 (85 ETDRS letters) were 90% and 15%, respectively. Residual ME and microaneurysms were observed in 85% and 35% of patients. Microaneurysm formation was associated with delayed initial therapy.

Conclusion

Prompt initiation of IVR injection provided a better visual prognosis at month 6 and suppressed the microaneurysm formation.