Crystalline retinopathy: Unifying pathogenic pathways of disease

DESCRIBING THE LOCATION AND MORPHOLOGY OF THE DOTS IN WHITE DOT FOVEA USING ADAPTIVE OPTICS

PURPOSE

To characterize the white dots in white dot fovea, an entity chiefly described in Japan, using adaptive optics imaging and propose a hypothesis regarding their origin.

METHOD

The patient underwent comprehensive ophthalmic examination, including color and green monochromatic fundus photography, fluorescein angiography, spectral-domain optical coherence tomography, and adaptive optics imaging.

RESULTS

An asymptomatic 66-year-old Korean woman presented with bilateral white, glistening deposits in a ring pattern around the fovea of both eyes. The dots were highly reflective on green monochromatic images, were not visible on fluorescein angiography, and appeared hyperreflective in the inner retina using spectral-domain optical coherence tomography. Adaptive optics showed polygonal granules ranging from 1 to 10 μ m in size. The patient denied any systemic disorder or the use of any medications related to crystalline retinopathy. The patient had lived in Japan for 35 years before just moving to the United States.

CONCLUSION

The location, small size, and polygonal shape of the dots in white dot fovea are suggestive of intraretinal deposition of crystals, and not cells on the surface of the fovea as has been previously proposed. Carotenoid deposition related to dietary habits is a plausible cause because of the similarity to other retinopathies associated to these compounds.

Nationwide Screening Practices for Tamoxifen Retinal Toxicity in South Korea: A Population-Based Cohort Study

(1) Background/Objectives: To investigate the nationwide screening practices and trends in tamoxifen retinal toxicity (tamoxifen retinopathy) in South Korea using national health insurance claims data. (2) Methods: A total of 43,848 patients who started tamoxifen therapy between 2015 and 2020 and had no prior ophthalmic diseases or other conditions requiring screening for retinopathy were included. The annual numbers of tamoxifen users and new initiators of tamoxifen therapy were assessed. The screening examinations were separated into baseline (first ophthalmic examination after tamoxifen administration) and subsequent monitoring examinations. The timing and modalities for the baseline and subsequent monitoring examinations performed between 2015 and 2021 were assessed in tamoxifen users. (3) Results: The annual number of tamoxifen users increased over the study period from 54,056 in 2015 to 81,720 in 2021. The number of patients who underwent ophthalmic examination after tamoxifen administration was 8961 (20.4%). Baseline screening was performed in 6.5% of patients within 1 year of use, and subsequent monitoring was performed in 27.8% of patients who underwent baseline screening. Funduscopy or fundus photography was performed most commonly for baseline screening and subsequent monitoring (99.0% and 98.6%, respectively), while optical coherence tomography was performed only in 21.9% and 29.6% of baseline and monitoring examinations, respectively. The average number of monitoring examinations per year was 0.68 ± 0.45. Although the annual percentage of patients receiving a baseline examination within 1 year gradually increased over time, the percentage of those with subsequent monitoring performed within 1 year was similar over the study period. (4) Conclusions: Our finding, appropriate screening in a small proportion of patients receiving tamoxifen, suggests the need to promote awareness among healthcare professionals and develop a standardized approach for screening for tamoxifen retinopathy.

En face OCT analysis of Bietti's crystalline dystrophy

Objective

To describe the multimodal imaging features, including en face optical coherence tomography (OCT), of Bietti's crystalline dystrophy (BCD).

Methods

Wide field fundus photography, autofluorescence (FAF) imaging, and cross sectional and en face OCT were performed in a case of BCD. The level of the crystals in the retina were analyzed.

Results

A 42-year-old patient was referred for retinal evaluation with nyctalopia, photophobia and metamorphopsia. Retinal examination and wide field color fundus photography were remarkable for bilateral crystalline deposits in the posterior pole and midperipheral retina. Wide field FAF showed extensive nummular atrophy of the retinal pigment epithelium (RPE) in the macula and periphery. Spectral-domain (SD) OCT illustrated bilateral chorioretinal atrophy in the macula. En face SD OCT captured the hyperreflective crystals in various retinal layers, depending on the selected segmentation. The patient was diagnosed with BCD and genetic testing confirmed the diagnosis (CYP4V positive for two variants).

Conclusion

In this case report, we describe the multimodal imaging features of Bietti's Crystalline Dystrophy. Wide field FAF illustrated diffuse nummular RPE atrophy in the posterior pole and periphery and en face OCT captured the hyperreflective crystals in different layers of the retina.

Resolution of Crystalline Retinopathy After Kidney Transplant for Hyperoxaluria

This case report discusses the evolution of crystalline retinopathy secondary to systemic hyperoxalosis after kidney transplant for hyperoxaluria was performed.

Tamoxifen retinopathy: A comprehensive review

Tamoxifen is a selective estrogen receptor modulator used mainly for the treatment of breast cancer. Based on the case reports and studies performed to date on the retinal toxicity of tamoxifen, retinopathy appears to occur in as many as 12% of patients taking 20 mg tamoxifen a day for over 2 years. Of this 12%, as many as half develop symptomatic changes in visual acuity. Retinal changes consist primarily of crystalline deposits, cystoid macular edema, hyperreflective deposits in the inner retinal layers, and telangiectasia. Tamoxifen retinopathy is currently managed by discontinuing tamoxifen therapy as the cancer prognosis permits; however, discontinuing therapy demonstrates little to no improvement in visual acuity once visual changes have taken place. Intravitreal injections of steroids or antivascular endothelial growth factor therapy have been performed, but require further studying before conclusions can be made. Until then, optical coherence tomography screening for retinal changes should be performed every 6 months for patients who have been on tamoxifen therapy for 2 years or more. This way, patients can become aware of retinal changes, and their physicians can consider adjusting tamoxifen therapy before they risk developing changes in visual acuity.

Foveal cone loss in tamoxifen maculopathy: a case report

BACKGROUND

Tamoxifen is used in low dose concentrations (20-40 mg per day) as a therapy for breast cancer but is known to have ocular side effects. In this case report, the foveal cone integrity in a tamoxifen-treated patient who complained of a small central scotoma in the left eye while reading was examined using high resolution adaptive optics imaging.

CASE PRESENTATION

Both eyes of a 54-year-old Caucasian, non-hispanic female who had been treated with tamoxifen for 1.5 years were examined using various imaging modalities including fundus photography, fundus autofluorescence, fluorescein angiography, spectral-domain optical coherence tomography, and adaptive optics scanning laser ophthalmoscopy. Clinical spectral-domain optical coherence tomography showed a very small disruption to the photoreceptor layer at the fovea in the left eye only. However, adaptive optics scanning laser ophthalmoscopy imaging revealed foveal cone loss in both eyes, but to a lesser extent in the right eye. Inner retinal changes were not observed in either eye.

CONCLUSION

The area of cone loss was similar in size to a single newsprint letter when projected onto the retina, matching the patient's description of a scotoma in the left eye. Given the isolated loss of foveal cone photoreceptors with the absence of previously reported inner retinal and vascular changes, our results may indicate the earliest retinal changes associated with tamoxifen retinopathy.

Novel ophthalmic findings and deep phenotyping in Williams-Beuren syndrome

BACKGROUND/AIMS

To characterise the ocular manifestations of Williams-Beuren syndrome (WBS) and compare these to patients with isolated elastin mediated supravalvular aortic stenosis (SVAS).

METHODS

Fifty-seven patients with a diagnosis of WBS and five with SVAS underwent comprehensive ophthalmic evaluation at the National Institutes of Health from 2017 to 2020, including best-corrected visual acuity, slit-lamp biomicroscopy, optical biometry, dilated fundus examination, optical coherence tomography and colour fundus imaging.

RESULTS

Mean age of the 57 WBS patients was 20.3 years (range 3-60 years). Best-corrected visual acuity ranged from 20/20 to 20/400 with mean spherical equivalent near plano OU. Twenty-four eyes (21.8%) had an axial length (AL) less than 20.5 mm and 38 eyes (34.5%) had an AL measuring 20.5-22.0 mm. Stellate iris and retinal arteriolar tortuosity were noted in 30 (52.6%) and 51 (89.5%) WBS patients, respectively. Novel retinal findings in WBS included small hypopigmented retinal deposits (OD 29/57, OS 27/57) and broad foveal pit contour (OD 44/55, OS 42/51). Of the five patients with SVAS, none had stellate iris or broad foveal pit contour while 2/5 had retinal arteriolar tortuosity.

CONCLUSION

WBS is a complex multisystem genetic disorder with diverse ophthalmic findings that differ from those seen in isolated elastin mediated SVAS. These results suggest other genes within the WBS critical region, aside from ELN, may be involved in observed ocular phenotypes and perhaps broader ocular development. Furthermore, retinal arteriolar tortuosity may provide future insight into systemic vascular findings in WBS.

Cholesterol crystal formation is a unifying pathogenic mechanism in the development of diabetic retinopathy

AIMS/HYPOTHESIS

Hyper-reflective crystalline deposits found in retinal lesions have been suggested to predict the progression of diabetic retinopathy, but the nature of these structures remains unknown.

METHODS

Scanning electron microscopy and immunohistochemistry were used to identify cholesterol crystals (CCs) in human donor, pig and mouse tissue. The effects of CCs were analysed in bovine retinal endothelial cells in vitro and in db/db mice in vivo using quantitative RT-PCR, bulk RNA sequencing, and cell death and permeability assays. Cholesterol homeostasis was determined using 2H2O and 2H7-cholesterol.

RESULTS

We identified hyper-reflective crystalline deposits in human diabetic retina as CCs. Similarly, CCs were found in the retina of a diabetic mouse model and a high-cholesterol diet-fed pig model. Cell culture studies demonstrated that treatment of retinal cells with CCs can recapitulate all major pathogenic mechanisms leading to diabetic retinopathy, including inflammation, cell death and breakdown of the blood-retinal barrier. Fibrates, statins and α-cyclodextrin effectively dissolved CCs present in in vitro models of diabetic retinopathy, and prevented CC-induced endothelial pathology. Treatment of a diabetic mouse model with α-cyclodextrin reduced cholesterol levels and CC formation in the retina, and prevented diabetic retinopathy.

CONCLUSIONS/INTERPRETATION

We established that cholesterol accumulation and CC formation are a unifying pathogenic mechanism in the development of diabetic retinopathy.

An In-Depth Single-Gene Worldwide Carrier Frequency and Genetic Prevalence Analysis of CYP4V2 as the Cause of Bietti Crystalline Dystrophy

Conclusions

Our analysis estimates BCD prevalence and revealed large differences among various populations. Moreover, it highlights advantages and limitations of the gnomAD database.

Methods

CYP4V2 gnomAD data and reported mutations were used to calculate carrier frequency of each variant. An evolutionary-based sliding window analysis was used to detect conserved protein regions. Potential exonic splicing enhancers (ESEs) were identified using ESEfinder.

Purpose

Bietti crystalline dystrophy (BCD) is a rare monogenic autosomal recessive (AR) chorioretinal degenerative disease caused by biallelic mutations in CYP4V2. The aim of the current study was to perform an in-depth calculation of worldwide carrier frequency and genetic prevalence of BCD using gnomAD data and comprehensive literature CYP4V2 analysis.

Results

We identified 1171 CYP4V2 variants, 156 of which were considered pathogenic, including 108 reported in patients with BCD. Carrier frequency and genetic prevalence calculations confirmed that BCD is more common in the East Asian population, with ∼19 million healthy carriers and 52,000 individuals who carry biallelic CYP4V2 mutations and are expected to be affected. Additionally, we generated BCD prevalence estimates of other populations, including African, European, Finnish, Latino, and South Asian. Worldwide, the estimated overall carrier frequency of CYP4V2 mutation is 1:210, and therefore, ∼37 million individuals are expected to be healthy carriers of a CYP4V2 mutation. The estimated genetic prevalence of BCD is about 1:116,000, and we predict that ∼67,000 individuals are affected with BCD worldwide.

Translational Relevance

This analysis is likely to have important implications for genetic counseling in each studied population and for developing clinical trials for potential BCD treatments.

A patient advocating for transparent science in rare disease research

300 million people live with at least one of 6,000 rare diseases worldwide. However, rare disease research is not always reviewed with scrutiny, making it susceptible to what the author refers to as nontransparent science. Nontransparent science can obscure animal model flaws, misguide medicine regulators and drug developers, delay or frustrate orphan drug development, or waste limited resources for rare disease research. Flawed animal models not only lack pharmacologic relevance, but also give rise to issue of clinical translatability. Sadly, these consequences and risks are grossly overlooked. Nontransparency in science can take many forms, such as premature publication of animal models without clinically significant data, not providing corrections when flaws to the model are discovered, lack of warning of critical study limitations, missing critical control data, questionable data quality, surprising results without a sound explanation, failure to rule out potential factors which may affect study conclusions, lack of sufficient detail for others to replicate the study, dubious authorship and study accountability. Science has no boarders, neither does nontransparent science. Nontransparent science can happen irrespective of the researcher's senority, institutional affiliation or country. As a patient-turned researcher suffering from Bietti crystalline dystrophy (BCD), I use BCD as an example to analyze various forms of nontransparent science in rare disease research. This article analyzes three papers published by different research groups on Cyp4v3^-/-, high-fat diet (HFD)-Cyp4v3^-/-, and Exon1-Cyp4v3^-/- mouse models of BCD. As the discussion probes various forms of nontransparent science, the flaws of these knockout mouse models are uncovered. These mouse models do not mimic BCD in humans nor do they address the lack of Cyp4v3 (murine ortholog of human CYP4V2) expression in wild type (WT) mouse retina which is markedly different from CYP4V2 expression in human retina. Further, this article discusses the impact of nontransparent science on drug development which can lead to significant delays ultimately affecting the patients. Lessons from BCD research can be helpful to all those suffering from rare diseases. As a patient, I call for transparent science in rare disease research.

Diagnostic and Management Strategies of Bietti Crystalline Dystrophy: Current Perspectives

Bietti crystalline dystrophy (BCD) is a rare, genetically determined chorioretinal dystrophy presenting with intraretinal crystalline deposits and varying degrees of progressive chorioretinal atrophy commencing at the posterior pole. In some cases, there can be concomitant corneal crystals noted first in the superior or inferior limbus. CYP4V2 gene, a member of the cytochrome P450 family is responsible for the disease and more than 100 mutations have been defined thus far. However, a genotype-phenotype correlation has not been established yet. Visual impairment commonly occurs between the second and third decades of life. By the fifth or sixth decade of life, vision loss can become so severe that the patient may potentially become legally blind. Multitudes of multimodal imaging modalities can be utilized to demonstrate the clinical features, course, and complications of the disease. This present review aims to reiterate the clinical features of BCD, update the clinical perspectives with the help of multimodal imaging techniques, and overview its genetic background with future therapeutic approaches.

Fleck-like lesions in CEP290-associated leber congenital amaurosis: a case series

PURPOSE

To provide a detailed ophthalmic phenotype of a small cohort of patients with Leber Congenital Amaurosis (LCA) caused by mutations in CEP290 (CEP290-LCA) with a focus on elucidating the origin of yellow-white lesions observed in 30% of patients with this condition.

METHODS

This is a retrospective review of records of five patients with CEP290-LCA. Patients had comprehensive ophthalmic evaluations. Visual function was assessed with full-field electroretinograms (ffERGs) and full-field sensitivity testing (FST). Multimodal imaging was performed with spectral domain optical coherence tomography (SD-OCT), fundus autofluorescence (FAF) with short- (SW) and near-infrared (NIR) excitation wavelengths.

RESULTS

All patients showed relative structural preservation of the foveal and near midperipheral retina separated by a pericentral area of photoreceptor loss. Yellow-white, fleck-like lesions in an annular distribution around the near midperiphery co-localized with hyperreflective lesions on SD-OCT. The lesions located between the inner segment ellipsoid signal and the apical retinal pigment epithelium (RPE). The inner retina was normal. Longitudinal observations in one of the patients indicates the abnormalities may represent an intermediate stage in the degenerative process between the near normal appearing retina previously documented in young CEP290-LCA patients and the pigmentary retinopathy observed along the same region in older individuals.

CONCLUSIONS

We speculate that fleck-like lesions in CEP290-LCA correspond to malformed, rudimentary or degenerated, including shed, photoreceptor outer segments. The topography and possible origin of the abnormalities may inform the planning of evolving genetic therapies for this disease.

Presumed Bietti crystalline dystrophy with optic nerve head drusen: a case report

Background

Bietti crystalline dystrophy is primarily a retinal dystrophy caused by a CYP4V2 mutation and typically presents with crystalline retinal deposits in the posterior fundus.

Case presentation

We present the case of an otherwise healthy 39-year-old Iranian woman with no family history of ocular disease who suffered with progressive vision loss that had started 2 years prior to presentation. Ocular examination revealed blurry optic nerve head margin and diffuse retinal crystalline deposit in both eyes. Spectral domain optical coherence tomography images showed retinal crystals, located mostly in outer retinal layers, with some areas of outer retinal tubulation and attenuation of outer retinal layers. Crystalline deposits were better visualized on near-infrared images as hyperreflective spots. Fundus autofluorescence images showed hyperautofluorescence areas on optic nerve head consistent with optic nerve head drusen and large hypoautofluorescence areas in posterior retina consistent with retinal pigment epithelium atrophy. Cystinosis was ruled out by blood testing.

Conclusion

Bietti crystalline dystrophy may be associated with optic nerve head drusen.

Characterization of West African Crystalline Macular Dystrophy in the Ghanaian Population

OBJECTIVE/PURPOSE

West African Crystalline Maculopathy (WACM) is characterized by the presence of macular hyper-refractile crystal-like deposits. Although the underlying pathophysiology has not been elucidated, a few biological drivers have been proposed. We analysed a large WACM case series to gain a more robust understanding of its features and etiology.

DESIGN

Prospective, Cross-sectional cohort study.

SUBJECTS/PARTICIPANTS

Participants with WACM were selected from the large cohort recruited into the Ghana Age-Related Macular Degeneration Study (Ghana AMD Study).

METHODS

Demographic and detailed medical histories, full ophthalmic examinations, digital colour fundus photographs and optical coherence tomography (OCT) images were obtained. All WACM cases were evaluated by three retina experts. Crystal numbers, location, and distribution were determined. Associations between WACM and Caucasian AMD risk variants were assessed using Firth's bias-reduced logistic regression, including age and gender as covariates.

MAIN OUTCOME MEASURES

Phenotypic features of, and genetic associations with, WACM.

RESULTS

WACM was identified in 106 eyes of 53 participants: 22 were bilateral and 24 unilateral. Grading for AMD was not possible in one eye of seven WACM participants; therefore, laterality was not assessed in these subjects. Thirty-eight participants were female, and 14 male; gender was unrecorded for one participant. Mean age was 68.4 years (range 45-101). OCT demonstrated typical WACM crystals, which were more easily identified at high contrast and predominantly located at the inner limiting membrane (ILM). In eyes with co-pathology, crystals localised deeper in the inner retina with wider retinal distribution over co-pathology lesions. There was no age or gender association. A significant association was observed between the complement factor H (CFH) 402H risk variant and WACM.

CONCLUSION

This study confirms localization of crystals adjacent to the ILM, and distribution over lesions in eyes with co-pathology. Evaluation of OCT images under high contrast allows improved identification. WACM may be associated with the CFH-CFHR5 AMD-risk locus identified amongst Caucasians; however, it is also possible that combination of crystals and the CFH 402H allele increases the risk for developing late AMD. Further analyses using larger sample sizes are warranted to identify causalities between genotype and WACM phenotype.

Case Series: West African Crystalline Maculopathy

SIGNIFICANCE

West African crystalline maculopathy is a rare crystalline maculopathy without a clear etiology. Although the crystals do not appear to be visually significant, there may be a role in the breakdown of the blood-retina barrier within the pathogenesis of this disorder.

PURPOSE

The purpose of this case series is to describe two cases of West African crystalline maculopathy. These crystals do not affect vision, nor visual function. Because there are only 39 other documented cases in the literature, it is imperative to understand the differences and similarities in this rare maculopathy.

CASE SERIES

Case 1 was a 65-year-old Black woman with a history of proliferative diabetic retinopathy after panretinal photocoagulation was seen for routine examination. She recently emigrated from Tema, Ghana. Examination revealed asymmetric macular crystals consistent with West African crystalline maculopathy and quiescent proliferative diabetic retinopathy. Case 2 was a 60-year-old Black woman that presented for routine examination. She recently emigrated from Nigeria. Examination revealed macular crystals consistent with West African crystalline maculopathy with evidence of stage 1 hypertensive retinopathy and extramacular drusen.

CONCLUSIONS

West African crystalline maculopathy is a rare disorder that should be considered in patients who present with asymptomatic foveal crystalline deposits who are immigrants from West African countries.

A systematic review of cases of West African crystalline maculopathy

AIM

West African crystalline maculopathy (WACM) is, reportedly, a rare condition whose aetiology remains unclear. This study aims to describe the epidemiology, summarizing the identified risk factors and clinical characteristics of cases of WACM, with the goal of highlighting presentation patterns and the clinical course of the condition.

METHODS

A comprehensive PubMed, Medline, EMBASE, Web of Science, OMIM and Google scholar search of all articles written in English, and non-English language articles with abstract translated to English on WACM was carried out. Only full case reports and series were included. Data reviewed included epidemiology, risk factors, clinical presentations, imaging characteristics, management and prognosis of WACM. Information on the location of the study was also extracted.

RESULTS

Ten studies - seven case reports and three case series - comprising of 30 patients were included. The patients were from West, Central and North-east Africa, with all the studies carried out in North America and Europe. The majority of the patients (76.7%) had diabetes mellitus, 80% had a vascular retinopathy (diabetic retinopathy, sickle cell retinopathy, familial exudative vitreoretinopathy and branch retinal vein occlusion) and 50% had macular oedema. There was no report of associated visual impairment or retinal degeneration. Clinical improvement in the number of crystals was documented in two cases with retinal laser photocoagulation for associated vascular retinopathies. Clinical observation was employed by most clinicians.

CONCLUSION

West African crystalline retinopathy is a seemingly innocuous condition affecting black or African people, who were also born in Africa. The majority of the patients have a vascular retinopathy. Longitudinal studies, particularly in Africa, may be required to elucidate the aetiology, as well as the long-term prognosis, of the crystals.

Crystalline Maculopathy Secondary to Retinal Tear Without Detachment

Purpose:

Crystalline maculopathy secondary to chronic retinal detachment (RD) has previously been described. This article proposes a novel mechanism to explain crystalline formation in the absence of RD.

Methods:

Two patients, who were referred for routine examination, were found to have a crystalline maculopathy in the setting of an asymptomatic, chronic-appearing, peripheral retinal tear. Fundoscopy and optical coherence tomography were used to assess the crystals and tear. No specimens were obtained.

Results:

We describe 2 cases of a crystalline maculopathy secondary to an asymptomatic peripheral retinal tear. We hypothesized macrophage ingestion of photoreceptor segments emanating from the tear may have contributed to macular crystalline deposition.

Conclusions:

Because crystalline maculopathy can present in the setting of RD, there may be a shared pathogenesis between the 2 conditions.

Multimodal imaging of an RPGR carrier female

Background: Retinitis pigmentosa GTPase regulator (RPGR) gene mutations are a common cause of X-linked retinitis pigmentosa and X-linked cone-rod dystrophy. There have been no previous reports of association with crystalline retinopathy or pseudo-crystalline retinopathy.Materials and Methods: We describe the history, clinical findings, retinal imaging, and electrodiagnostic studies of a patient with a tapetal-like reflex (TLR) and pseudo-crystalline retinopathy secondary to RPGR mutation.Case Description: Asymptomatic TLR secondary to RPGR mutation was diagnosed in a 14-year-old African American female with a family history of retinal dystrophy and no other past ophthalmic or medical history. Pseudo-crystalline retinopathy was observed on the Optos scanning laser ophthalmoscopy (SLO) imaging system but not on color fundus photography (CFP). Evidence of a TLR secondary to RPGR mutation was confirmed by CFP, autofluorescence, and genetic testing.Conclusion: We present a case of pseudo-crystalline retinopathy seen on Optos imaging in a patient with a TLR secondary to RPGR mutation.

Non-invasive multimodal imaging of Diabetic Retinopathy: A survey on treatment methods and Nanotheranostics

Diabetes Retinopathy (DR) is one of the most prominent microvascular complications of diabetes. It is one of the pre-eminent causes for vision impairment followed by blindness among the working-age population worldwide. The de facto cause for DR remains challenging, despite several efforts made to unveil the mechanism underlying the pathology of DR. There is quite less availability of the low cost pre-emptive theranostic imaging tools in terms of in-depth resolution, due to the multiple factors involved in the etiology of DR. This review work comprehensively explores the various reports and research works on all perspectives of diabetic retinopathy (DR), and its mechanism. It also discusses various advanced non-destructive imaging modalities, current, and future treatment approaches. Further, the application of various nanoparticle-based drug delivery strategies used for the treatment of DR are also discussed. In a nutshell, the present review work bolsters the pursuit of the development of an advanced non-invasive optical imaging modal with a nano-theranostic approach for the future diagnosis and treatment of DR and its associated ocular complications.

Bilateral Macular Hole Related to Tamoxifen Low-Dose Toxicity

Bilateral macular hole is a rare secondary effect of tamoxifen, a condition which is probably underdiagnosed. We describe the case of a 63-year-old woman who had received low-dose treatment with tamoxifen for 10 years. She presented with a best-corrected visual acuity of 20/40 in both eyes and bilateral macular hole with posterior hyaloid attachment. No reflective deposits were observed. A 23-gauge pars plana vitrectomy with internal limiting membrane peeling and gas tamponade was performed in the right eye with no anatomical or functional improvement. The most accepted mechanism of macular hole related to tamoxifen is Müller cell toxicity with retinal tissue loss. Therefore, it seems that the standard procedure used in idiopathic macular hole is not the optimal choice, due to a different pathogenic mechanism.

Calcium oxalate crystals retinopathy following domino liver transplant: A case report

INTRODUCTION

Hyperoxaluria is a rare cause of hereditary crystalline retinopathy. We report the first case of acquired calcium oxalate crystalsretinopathy following domino liver transplantation (DLT).

CLINICAL CASE

A 72-year-old patient was referred for bilateral visual impairment 9 months after DLT. Slit lamp examination was unremarkable. Fundus examination revealed calcium oxalate crystals accumulation within both retina. Owing to multi-organ failure, the patient underwent combined liver-kidney retransplantation. During the following two years, calcium oxalate crystals accumulation within the retina gradually decreased and visual acuity improved. Nevertheless, OCT-angiography revealed abnormalities in the inner and outer retinal vascular plexus (i.e. retinal vessels occlusion and dilatation). Visual field examination revealed bilateral constriction associated with decreased optic nerve fibre layer thickness suggesting optic nerve atrophy.

CONCLUSION

This case highlights the need for ophthalmologists to consider the diagnosis of acquired hyperoxaluria in patients with progressive bilateral visual impairment following DLT, especially if the postoperative course is marked by renal failure. Moreover, even after liver-kidney transplantation with a conventional graft, visual function can remain impaired owing to maculopathy and optic atrophy.

Tamoxifen maculopathy: The importance of screening and long follow-up

We report a case of a patient treated with tamoxifen 20mg daily as hormone therapy for breast cancer. On regular ophthalmological follow-up, tamoxifen maculopathy was detected on SD-OCT (Spectral Domain Optic Coherence Tomography, Carl Zeiss Meditec®), so the medication was discontinued. Despite discontinuation of the medication, the maculopathy progressed over time. We have been following our patient for seven years. Tamoxifen may produce a toxic maculopathy which may progress despite discontinuation of the medication. We consider our case interesting, given the lengthy follow-up of the patient with sequential SD-OCT images. To the best of our knowledge, our case represents the longest follow-up period for a patient with tamoxifen maculopathy. Moreover, we would like to stress the importance of screening in asymptomatic patients on this medication, in order to detect early pathological signs.

Macular crystalline inclusions in Sjögren-Larsson syndrome are dynamic structures that undergo remodeling

BACKGROUND

Sjögren-Larsson syndrome (SLS) is a rare genetic neurocutaneous disease caused by mutations in ALDH3A2 that results in deficiency of fatty aldehyde dehydrogenase and accumulation of fatty aldehydes and alcohols. The disease is associated with ichthyosis, spasticity, and intellectual disability. Patients exhibit a characteristic retinopathy with macular crystalline inclusions that first appear in early childhood and increase with age. Once formed, the inclusions are thought to be inert and irreversible. We sought to document how the crystalline inclusions change over time.

MATERIALS AND METHODS

Serial retinal photographs of 4 SLS subjects (9-23 years old) were taken over a period of 1-3 years. Images were compared by visual inspection and analyzed using ImageJ/Fiji software to observe changes.

RESULTS

Visual inspection of retinal photographs of SLS subjects taken over time demonstrated distinctive changes in crystalline inclusions. New inclusions were formed and some established inclusions regressed. These changes were conveniently demonstrated with software-based photographic image analysis.

CONCLUSIONS

We conclude that macular inclusions in SLS are not simply inert deposits, but are dynamic structures that form over time and are subject to remodeling. This conclusion provides new insight into the interplay between the metabolic defect and retinal pathology in SLS, and raises the potential for new therapeutic approaches to reverse some aspects of the maculopathy.

Role of red free imaging, retinal reflectance and fundus autofluorescence in Bietti crystalline dystrophy: case report

Bietti crystalline dystrophy (BCD), a rare autosomal recessive hereditary disorder, is identified by its clinical features. It is characterised by crystalline deposits and hence called crystalline retinopathy. The retinopathy progresses with age, showing a decrease in the number of crystalline deposits and increase in the area of chorioretinal degeneration, which spreads in a centrifugal pattern. Thus, BCD can be confused with other disorders with crystalline-like deposits and chorioretinal degenerations. The red-free and near-infrared reflectance allows prominent visualisation of crystalline deposits that may be missed. The non-inferiority of red-free imaging and its wider availability could allow its use as a screening tool. The enhanced depth imaging optical coherence tomography shows crystalline deposits throughout the retina and outer retinal tubulation. Thus, multimodality imaging can act as an adjunct in diagnosis, monitoring and follow up in these cases, acting not only as a teaching tool but also giving an insight into the underlying pathophysiology of the disorder.

Plain language summary

Use of imaging in diagnosis of Bietti crystalline dystrophy Bietti crystalline dystrophy is a rare familial disorder but is not shown in all family members and may skip generations, as it has an autosomal recessive pattern of inheritance. It shows refractile yellow-white crystalline deposits and degenerative changes in the retina. These crystalline deposits disappear with age while degenerative changes increase and spread from centre to the periphery. This may cause difficulty in early detection, and confusion with similar degenerative diseases of the retina. The use of various imaging modalities can help in diagnosis and follow up of these cases. These modalities also provide understanding of the basic disease process.

OCT Angiography Findings of Tamoxifen Retinopathy: Similarity with Macular Telangiectasia Type 2

PURPOSE

We aimed to describe the vascular changes in eyes associated with tamoxifen retinopathy using OCT angiography (OCTA) and to compare these changes with abnormalities in macular telangiectasia type 2 (MacTel 2) previously reported in the literature.

DESIGN

Retrospective, observational study.

PARTICIPANTS

Seventeen eyes with tamoxifen retinopathy and 17 eyes of age-matched healthy control participants.

METHODS

The medical records of patients who visited the ophthalmology department with a history of taking tamoxifen were reviewed. Tamoxifen retinopathy was diagnosed based on typical spectral-domain (SD) OCT findings, such as intraretinal cavitation, photoreceptor disruption, or both. Multimodal imaging, particularly focused on OCTA, was analyzed. To compare vessel density in OCTA, age-matched normal control participants also were enrolled.

MAIN OUTCOME MEASURES

Descriptive appraisal of the vascular abnormalities and objective quantification of vessel density associated with tamoxifen retinopathy.

RESULTS

Among 292 patients who were screened, 26 were diagnosed with tamoxifen retinopathy. Of these, 17 eyes of 10 patients who were evaluated using OCTA were included. All patients were women, with a median patient age of 65.0 years. They were treated with tamoxifen as adjuvant endocrine therapy for breast cancer. All eyes showed intraretinal cavitation, and 8 eyes showed focal photoreceptor disruption as well, on OCT. On OCTA imaging, 14 eyes (82.4%) showed saccular capillary telangiectasia at the deep capillary plexus and 6 eyes (35.3%) showed right-angled vessels. Foveal vessel density of the superficial plexus was significantly lower in eyes with tamoxifen retinopathy than in control participants (P = 0.003). Crystalline deposits on fundus photographs (12 eyes [70.6%]) and increased autofluorescence on fundus autofluorescence (16 eyes [94.1%]) also were noted as characteristic findings of tamoxifen retinopathy.

CONCLUSIONS

In addition to morphologic changes of tamoxifen retinopathy in SD OCT, its vascular changes on OCTA, such as telangiectatic vascular change at the deep capillary plexus and right-angled vessels, are similar to those observed in the early stages of MacTel 2.

Multimodal imaging of benign yellow dot maculopathy

PURPOSE

To describe the clinical features of 2 unrelated families affected with Benign Yellow Dot Maculopathy and to analyze anatomical and functional findings of this peculiar phenotype Methods: Case series Results: We retrospectively described 5 patients (3 males, 2 females) affected with Benign Yellow Dot Maculopathy. The mean age at referral was 50,8 years (range 34-69 yrs.). All patients were characterized by a good visual acuity (20/20 in both eyes) and by symmetric multiple yellow dots at the posterior pole in both eyes. In 3 patients (P1, P3, P4) the yellow dots were mainly located at the nasal side of the macula. The yellow dots appeared hyper-autofluorescent at the fundus autofluorescence (FAF) imaging. OCT examination revealed in 3 patients (P1, P3, P4) mild irregularities at the level of the retinal pigment epithelium (RPE) and at the interdigitation (IZ) and ellipsoid zone (EZ). OCT angiography (OCT-A), performed in 3 patients (P1, P4,P5), was normal. Adaptive Optics imaging (AO) showed a peculiar pattern of the cone mosaic: the yellow dots were detectable as hyper-reflective lesions at the macular region. In 2 patients (P1, P4) we reported a follow-up of 2 and 18 years respectively. Genetic examination performed on patient P1 did not reveal pathogenic variants for retinal dystrophies.

CONCLUSIONS

Our work confirmed the benign nature of this peculiar macular phenotype showing a normal macular function and a stable clinical picture during a long-term follow-up. Multimodal imaging allows a detailed detection and monitoring of Benign Yellow Dot Maculopathy.