The Utility of Fundus Fluorescein Angiography in Neuro-Ophthalmology

Managing idiopathic intracranial hypertension in the eye clinic

Idiopathic intracranial hypertension (IIH) is a neuro-ophthalmological condition characterised by a raised intracranial pressure and papilloedema that causes disabling headaches. The main risk factors of female sex and living with obesity have been known for some time, however the knowledge of the underlying pathophysiology is evolving. Papilloedema can impact the visual function, and the majority of people are offered acetazolamide. Those with sight threatening disease need urgent management, though there is little high quality evidence to recommend any particular surgical intervention. Headache treatment is an unmet clinical need and simple medication overuse advice has the potential to reduce the chronification of migraine-like headaches. IIH is emerging as a systemic metabolic disease distinct from people living with obesity alone. While weight loss is the main stay of disease modifying therapy this is challenging to access and many healthcare professionals that manage the condition have no formal training or accessible pathways for weight management. The aim of this "how to do it" article is to present the latest advances in knowledge of IIH that we pragmatically included in routine clinical care for people living with the condition.

Trends in application of fundus fluorescein angiography in fundus diseases during a recent ten-year period

PURPOSE

To analyze the trends in the application of fundus fluorescein angiography (FFA) in fundus diseases over ten years.

METHOD

It was a retrospective study. Patients who underwent FFA examinations between Jan 2012 and Dec 2021 in Eye Hospital of Wenzhou Medical University were included, excluding infants. Data included the fundus disease and examination time of FFA.

RESULTS

A total of 37,038 cases underwent FFA examinations in our hospital in the past decade, and the number of each year was 3,628, 2,232, 2,230, 2,351, 3,546, 3,924, 5,325, 4,202, 4,432 and 5,168 from 2012 to 2021, respectively. The top three diseases were central serous chorioretinopathy (CSC), diabetic retinopathy (DR) and retinal vein occlusion (RVO) over the years from 2012 to 2021. The fourth to eighth ranked diseases were uveitis, age-related macular degeneration (AMD), choroidal neovascularization (CNV), optic neuropathy (ON) and polypoid choroidal vasculopathy (PCV) 9 years from 2012 to 2020; while retinal artery occlusion (RAO) ranked eighth and PCV fell out of the first eight in 2021. Tumor, Eale's disease, macular hemorrhage (MH), epiretinal retinal membrane (ERM) and Coat's disease had consistent proportions over the years. There was a significant statistical difference in the proportion of disease components over the years from 2012 to 2021(p = 0.000).

CONCLUSION

Despite changes in annual distribution, CSC, DR, and RVO consistently ranked as the top three diseases requiring FFA examination. Changes might be related to the development of non-invasive fundus examination instruments and technologies. Indicated that FFA still hold its irreplaceable nature in diagnosing and understanding fundus diseases.

Susac syndrome: neurological update (clinical features, long-term observational follow-up and management of sixteen patients)

Susac syndrome is a likely autoimmune microangiopathy affecting the brain, retina and inner ear. Due to the rarity of this condition, diagnosis and treatment can be challenging. Diagnosis is based on the presence of the clinical triad of central nervous system dysfunction, branch retinal artery occlusions and sensorineural hearing loss. Typical MRI findings of callosal and peri-callosal lesions may assist in diagnosis. Clinical course can be monophasic, polycyclic or chronic continuous. It is important to look out for red flags to attain an accurate diagnosis and follow a therapeutic algorithm based on severity of the disease and response to treatment. Patients are treated with steroids and immunosuppressive agents with a variable response. Early aggressive treatment especially in severe cases, may help in preventing relapses and morbidity/disability. This study highlights important diagnostic features and proposes a treatment algorithm based on clinical experience from management of 16 patients from 2 neuroscience centres in the UK since 2007, who were followed up over a long period of 3-15 years.

Retro-Mode in NIDEK Mirante: A Comparative Analysis with Other Imaging Modalities for AMD and CSR

BACKGROUND

Retro-mode is a novel technique capable of creating pseudo-3D images of the retina. However, its clinical utility remains unknown. This study aimed to evaluate the Nidek Mirante multimodal imaging platform for ocular assessment in patients with various retinal conditions.

METHODS

A total of 115 participants with central serous chorioretinopathy (CSR) and age-related macular degeneration (AMD) were included. Two experienced graders independently evaluated the images, and statistical analysis was performed to assess interclass correlation coefficients (ICC) between graders and modalities; Results: For CSR detection, retro-mode demonstrated exceptionally high ICC rates (ICC = 1; 100%), while color and autofluorescence (FAF) showed moderate coefficients (0.69 and 0.78, respectively). The detection of pigment epithelial detachment was high across all methods, with only retro-mode deviated right (DR) allowing detection in 69% of cases, while retro-mode DR and deviated left (DL) achieved 100% detection. FAF-green achieved a 95% detection rate. In detecting retinal atrophy, most modalities demonstrated high detection rates, with the lowest detection rates offered by retro-mode DL (ICC = 0.85) and DR (ICC = 0.89), while retro-mode ring aperture offered 0.97. Infra-red and fluorescein angiography imaging offered the highest detection rates among the tested modalities, with 97% and 100%, respectively.

CONCLUSION

Retro-mode showed promise for comprehensive ocular evaluation and diagnosis, with certain imaging modalities demonstrating higher accuracy in detecting specific retinal features.

Diagnosis of Optic Disc Oedema: Fundus Features, Ocular Imaging Findings, and Artificial Intelligence

Optic disc swelling is a manifestation of a broad range of processes affecting the optic nerve head and/or the anterior segment of the optic nerve. Accurately diagnosing optic disc oedema, grading its severity, and recognising its cause, is crucial in order to treat patients in a timely manner and limit vision loss. Some ocular fundus features, in light of a patient's history and visual symptoms, may suggest a specific mechanism or aetiology of the visible disc oedema, but current criteria can at most enable an educated guess as to the most likely cause. In many cases only the clinical evolution and ancillary testing can inform the exact diagnosis. The development of ocular fundus imaging, including colour fundus photography, fluorescein angiography, optical coherence tomography, and multimodal imaging, has provided assistance in quantifying swelling, distinguishing true optic disc oedema from pseudo-optic disc oedema, and differentiating among the numerous causes of acute optic disc oedema. However, the diagnosis of disc oedema is often delayed or not made in busy emergency departments and outpatient neurology clinics. Indeed, most non-eye care providers are not able to accurately perform ocular fundus examination, increasing the risk of diagnostic errors in acute neurological settings. The implementation of non-mydriatic fundus photography and artificial intelligence technology in the diagnostic process addresses these important gaps in clinical practice.

Values of optical coherence tomography angiography for diagnosing diabetic retinopathy and evaluating treatment outcomes

PURPOSE

To compare the consistency between fundus fluorescein angiography (FFA) and optical coherence tomography angiography (OCTA) for the diagnosis of diabetic retinopathy (DR).

MATERIALS AND METHODS

Ninety-six diabetic patients (185 eyes) treated from January 2019 to December 2019 underwent OCTA and FFA. The image characteristics of fundus lesions were recorded. Sixty-nine patients (137 eyes) who were diagnosed with DR by both examinations and needed to receive panretinal photocoagulation (PRP) were selected. The retinal nerve fiber layer (RNFL) thickness, macular superficial vascular complex (SVC) and deep vascular complex (DVC) blood flow density, 300μm area surrounding foveal avascular zone (FAZ) (FD300) blood flow density and FAZ parameters were compared.

RESULTS

The Kappa coefficient of FFA and OCTA for diagnosing DR was 0.537 (P=0.000). FFA and OCTA had substantial consistency for detecting retinal microaneurysms and macular edema (Kappa coefficient=0.643/0.616, P=0.000), perfect consistency for detecting retinal neovascularization and retinal non-perfusion area (Kappa coefficient=0.809/0.832, P=0.000), and moderate consistency for detecting structural changes in the macular ring (Kappa coefficient=0.423, P=0.000). The RNFL thickness in the peripapillary and the superior temporal, temporal inferior, inferior nasal and superior nasal regions rose 1 week after PRP but declined 1 year after treatment (P<0.05). The macular SVC, DVC and FD300 blood flow density declined 1 week after PRP but rose 1 year after treatment (P<0.05).

CONCLUSIONS

OCTA shows consistency with FFA for diagnosing DR, which remedies the deficiency of FFA. The reduction in fundus lesions after PRP can be quantified by OCTA.

Long-acting formulation strategies for protein and peptide delivery in the treatment of PSED

The invigoration of protein and peptides in serious eye disease includes age-related macular degeneration, choroidal neovascularization, retinal neovascularization, and diabetic retinopathy. The transportation of macromolecules like aptamers, recombinant proteins, and monoclonal antibodies to the posterior segment of the eye is challenging due to their high molecular weight, rapid degradation, and low solubility. Moreover, it requires frequent administration for prolonged therapy. The long-acting novel formulation strategies are helpful to overcome these issues and provide superior therapy. It avoids frequent administration, improves stability, high retention time, and avoids burst release. This review briefly enlightens posterior segments of eye diseases with their diagnosis techniques and treatments. This article mainly focuses on recent advanced approaches like intravitreal implants and injectables, electrospun injectables, 3D printed drug-loaded implants, nanostructure thin-film polymer devices encapsulated cell technology-based intravitreal implants, injectable and depots, microneedles, PDS with ranibizumab, polymer nanoparticles, inorganic nanoparticles, hydrogels and microparticles for delivering macromolecules in the eye for intended therapy. Furthermore, novel techniques like aptamer, small Interference RNA, and stem cell therapy were also discussed. It is predicted that these systems will make revolutionary changes in treating posterior segment eye diseases in future.

Optic Disc Edema and Elevated Intracranial Pressure (ICP): A Comprehensive Review of Papilledema

Papilledema is a swelling of the optic disc secondary to elevated intracranial pressure (ICP). We analyzed 79 peer-review journal articles and provided a concise summary of the etiology, epidemiology, pathophysiology, clinical presentation, evaluation, natural history, differential diagnosis, treatment, and prognosis of papilledema. Only studies written in English with the full text available were included. Although many etiologies of papilledema exist, idiopathic intracranial hypertension is the most common and, thus, a large focus of this review.

Quantification of retinal blood leakage in fundus fluorescein angiography in a retinal angiogenesis model

Blood leakage from the vessels in the eye is the hallmark of many vascular eye diseases. One of the preclinical mouse models of retinal blood leakage, the very-low-density-lipoprotein receptor deficient mouse (Vldlr-/-), is used for drug screening and mechanistic studies. Vessel leakage is usually examined using Fundus fluorescein angiography (FFA). However, interpreting FFA images of the Vldlr-/- model is challenging as no automated and objective techniques exist for this model. A pipeline has been developed for quantifying leakage intensity and area including three tasks: (i) blood leakage identification, (ii) blood vessel segmentation, and (iii) image registration. Morphological operations followed by log-Gabor quadrature filters were used to identify leakage regions. In addition, a novel optic disk detection algorithm based on graph analysis was developed for registering the images at different timepoints. Blood leakage intensity and area measured by the methodology were compared to ground truth quantifications produced by two annotators. The relative difference between the quantifications from the method and those obtained from ground truth images was around 10% ± 6% for leakage intensity and 17% ± 8% for leakage region. The Pearson correlation coefficient between the method results and the ground truth was around 0.98 for leakage intensity and 0.94 for leakage region. Therefore, we presented a computational method for quantifying retinal vascular leakage and vessels using FFA in a preclinical angiogenesis model, the Vldlr-/- model.

Aerosolised fluorescein can quantify FFP mask faceseal leakage: a cost-effective adaptation to the existing point of care fit test

BACKGROUND

A qualitative fit test using bitter-tasting aerosols is the commonest way to determine filtering face-piece (FFP) mask leakage. This taste test is subjective and biased by placebo. We propose a cheap, quantitative modification of the taste test by measuring the amount of fluorescein stained filter paper behind the mask using image analysis.

METHODS

A bitter-tasting fluorescein solution was aerosolised during mask fit tests, with filter paper placed on masks' inner surfaces. Participants reported whether they could taste bitterness to determine taste test 'pass' or 'fail' results. Filter paper photographs were digitally analysed to quantify total fluorescence (TF).

RESULTS

Fifty-six healthcare professionals were fit tested; 32 (57%) 'passed' the taste test. TF between the taste test 'pass' and 'fail' groups was significantly different (p<0.001). A cut-off (TF = 5.0 × 10⁶ units) was determined at precision (78%) and recall (84%), resulting in 5/56 participants (9%) reclassified from 'pass' to 'fail' by the fluorescein test. Seven out of 56 (12%) reclassified from 'fail' to 'pass'.

CONCLUSION

Fluorescein is detectable and sensitive at identifying FFP mask leaks. These low-cost adaptations can enhance exiting fit testing to determine 'pass' and 'fail' groups, protecting those who 'passed' the taste test but have high fluorescein leak, and reassuring those who 'failed' the taste test despite having little fluorescein leak.

Susac's Syndrome: An Updated Review

Susac's syndrome is a rare immune-mediated endotheliopathy that mainly affects young women. It is characterised by the presence of encephalopathy, retinal vaso-occlusive disease and hearing loss. Diagnosis is based on the clinical presentation, brain magnetic resonance imaging, retinal fluorescein angiography, and audiometry. Treatment consists of immunosuppressive therapy. This review focuses on recent developments in the diagnosis and management of the condition.

Acute monocular oligemia in a patient with migraine with aura demonstrated using OCT-angiography: A case report

Introduction:

Migraine is one of the most common causes of transient visual loss. Optical coherence tomography angiography (OCTA) provides fast and non-invasive imaging of the retinal vessels. We report one case of monocular retinal oligemia demonstrated using OCTA during a migraine attack with aura.

Case description:

A 27-year-old man with a previous history of migraine with visual aura was seen in the emergency room due to acute left hemicranial pain with positive visual symptoms in his right eye. The patient reported a blue stain in his right eye. Optical coherence tomography angiography (OCT-A) showed an extensive area of hypoperfusion in the macular region of his right eye. Forty-eight hours later visual symptoms had improved and the OCT-A showed a significant reduction in the area of hypoperfusion. Seven days later the patient was asymptomatic and retinal perfusion had returned to normal values.

Conclusion:

Monocular involvement suggests that these retinal vascular changes are independent from cerebral vascular changes, supporting the hypothesis of selective retinal ganglion cell layer spreading depression as the possible cause of some cases of retinal migraine.

Optical Coherence Tomography Angiography (OCTA) in Multiple Sclerosis and Neuromyelitis Optica Spectrum Disorder

Vascular changes are increasingly recognized as important factors in the pathophysiology of neuroinflammatory disease, especially in multiple sclerosis (MS). The relatively novel technology of optical coherence tomography angiography (OCTA) images the retinal and choroidal vasculature non-invasively and in a depth-resolved manner. OCTA provides an alternative quantitative measure of retinal damage, by measuring vascular density instead of structural atrophy. Preliminary results suggest OCTA is sensitive to retinal damage in early disease stages, while also having less of a "floor-effect" compared with commonly used OCT metrics, meaning it can pick up further damage in a severely atrophied retina in later stages of disease. Furthermore, it may serve as a surrogate marker for vascular pathology in the central nervous system. Data to date consistently reveal lower densities of the retinal microvasculature in both MS and neuromyelitis optica spectrum disorder (NMOSD) compared with healthy controls, even in the absence of prior optic neuritis. Exploring the timing of vascular changes relative to structural atrophy may help answer important questions about the role of hypoperfusion in the pathophysiology of neuroinflammatory disease. Finally, qualitative characteristics of retinal microvasculature may help discriminate between different neuroinflammatory disorders. There are however still issues regarding image quality and development of standardized analysis methods before OCTA can be fully incorporated into clinical practice.

Is a virtual clinic model a safe and effective way for assessing patients referred with suspiciously blurred optic discs? The blurred disc clinic

BACKGROUND

There are increasing numbers of referrals to ophthalmology departments due to blurred optic disc margins. In light of this and the COVID-19 pandemic we aimed to assess whether these patients could be safely assessed without direct contact between the clinician and patient.

METHODS

We retrospectively reviewed the records of consecutive patients seen in our 'blurred disc clinic' between August 2018 and October 2019. We then presented anonymous information from their referral letter, their visual fields and optic nerve images to two consultant neuro-ophthalmologists blinded to the outcome of the face-to-face consultation. In the simulated virtual clinic, the two consultants were asked to choose an outcome for each patient from discharge, investigate or bring in for a face-to-face assessment.

RESULTS

Out of 133 patients seen in the blurred disc clinic, six (4.5%) were found to have papilloedema. All six were identified by both neuro-ophthalmologists as needing a face-to-face clinic consultation from the simulated virtual clinic. One hundred and twenty (90%) patients were discharged from the face-to-face clinic at the first consultation. The two neuro-ophthalmologists chose to discharge 114 (95%) and 99 (83%) of these respectively from the simulated virtual clinic. The virtual clinic would have potentially missed serious pathology in only one patient who had normal optic discs but reported diplopia at the previous face-to-face consultation.

CONCLUSIONS

A virtual clinic model is an effective way of screening for papilloedema in patients referred to the eye clinic with suspicious optic discs. Unrelated or incidental pathology may be missed in a virtual clinic.

Diagnosis of chronic stage of hypertensive retinopathy based on spectral domain optical coherence tomography

Hypertensive retinopathy refers to the retinal vascular changes associated with systemic arterial hypertension. Hypertensive retinopathy can be divided into chronic and acute phases. A cross-sectional study was performed to explore a method of measurement in the diameters of retinal vessels for diagnosis of chronic hypertensive retinopathy based on spectral domain optical coherence tomography (SD-OCT). The central retinal artery diameter (CRAD), the central retinal vein diameter (CRVD), and the artery-to-vein ratio (AVR) were measured. A total of 119 subjects with 119 eyes were included in this study, in which 56 subjects with 56 eyes were included in hypertensive group and 63 subjects with 63 eyes were included in normotensive group. There were significant differences between the two groups in the CRAD (t = -2.14, P = .04) and the AVR (t = -2.59, P = .01). The cutoff point of 0.75 was determined by receiver operating characteristic (ROC) curve (area under the curve, AUC 0.786; 95% confidence interval, 95% CI 0.70-0.87). Multivariate logistic regression analysis showed the probability of AVR below to 0.75 was more in patients with high systolic blood pressure (odds ratio OR 4.39; P = .048), more in male (OR 4.15; P = .004) and more in smokers (OR 5.80; P = .01). Bland-Altman plots showed small mean bias between the measurements of the two technicians in the CRAD, the CRVD, and the AVR. In summary, application of SD-OCT is an accurate, reproducible, convenient method for measuring the diameters of retinal vessels. It is valuable for the diagnosis of chronic stage of hypertensive retinopathy.