Optical coherence tomography of cystoid macular edema associated with retinitis pigmentosa

Applications of artificial intelligence in diagnosis of uncommon cystoid macular edema using optical coherence tomography imaging: A systematic review

Cystoid macular edema (CME) is a sight-threatening condition often associated with inflammatory and diabetic diseases. Early detection is crucial to prevent irreversible vision loss. Artificial intelligence (AI) has shown promise in automating CME diagnosis through optical coherence tomography (OCT) imaging, but its utility needs critical evaluation. This systematic review assesses the application of AI to diagnosis CME, specifically focusing on disorders like postoperative CME (Irvine Gass syndrome) and retinitis pigmentosa without obvious vasculopathy, using OCT imaging. A comprehensive search was conducted across 6 databases (PubMed, Scopus, Web of Science, Wiley, ScienceDirect, and IEEE) from 2018 to November, 2023. Twenty-three articles met the inclusion criteria and were selected for in-depth analysis. We evaluate AI's role in CME diagnosis and its performance in "detection", "classification" and "segmentation" of OCT retinal images. We found that convolutional neural network (CNN)-based methods consistently outperformed other machine learning techniques, achieving an average accuracy of over 96% in detecting and identifying CME from OCT images. Despite certain limitations such as dataset size and ethical concerns, the synergy between AI and OCT, particularly through CNNs, holds promise for significantly advancing CME diagnostics.

New insights in the multimodal imaging of retinitis pigmentosa

Retinitis pigmentosa (RP) is a group of inherited rod-cone dystrophies, noted for a high genotypical and phenotypical heterogeneity.Traditionally, VA, visual field, and electroretinography have been used to assess RP progression. However, visual acuity and visual field tests are essentially subjective and, especially in the late stages of the disease, are unable to confidently reveal minor progression. Therefore, there is a need for novel examination modalities that rely on quantitative, structural measurements. In this regard, several non-invasive imaging techniques have been studied, including spectral-domain optical coherence tomography, optical coherence tomography angiography, and fundus autofluorescence. By correlating surrogate biomarkers with functional measurements of the disease, these techniques may be able to develop reliable outcome meters that can be used to gain a deeper understanding of the underlying causes of the disease and to assess the effectiveness of therapy even before an actual loss of vision occurs.In this review, we will summarize the recent imaging findings and biomarkers that have been identified in RP patients. Our goal is to provide information that can promptly aid in selecting patients for clinical trials and new gene therapies, monitoring the disease progression, and evaluating treatment outcomes.

Usher Syndrome on the Island of Ireland: A Genotype-Phenotype Review

Purpose

Usher syndrome (USH) is a genetically heterogeneous group of autosomal recessive (AR) syndromic inherited retinal degenerations (IRDs) representing 50% of deaf-blindness. All subtypes include retinitis pigmentosa, sensorineural hearing loss, and vestibular abnormalities. Thorough phenotyping may facilitate genetic diagnosis and intervention. Here we report the clinical/genetic features of an Irish USH cohort.

Methods

USH patients were selected from the Irish IRD registry (Target 5000). Patients were examined clinically (deep-phenotyping) and genetically using a 254 IRD-associated gene target capture sequencing panel, USH2A exon, and whole genome sequencing.

Results

The study identified 145 patients (24.1% USH1 [n = 35], 73.8% USH2 [n = 107], 1.4% USH3 [n = 2], and 0.7% USH4 [n = 1]). A genetic diagnosis was reached in 82.1%, the majority (80.7%) being MYO7A or USH2A genotypes. Mean visual acuity and visual field (VF) were 0.47 ± 0.58 LogMAR and 31.3° ± 32.8°, respectively, at a mean age of 43 years. Legal blindness criteria were met in 40.7%. Cataract was present in 77.4%. ADGRV1 genotypes had the most VF loss, whereas USH2A patients had greater myopia and CDH23 had the most astigmatism. Variants absent from gnomAD non-Finnish Europeans and ClinVar represented more than 20% of the variants identified and were detected in ADGRV1, ARSG, CDH23, MYO7A, and USH2A.

Conclusions

USH is a genetically diverse group of AR IRDs that have a profound impact on affected individuals and their families. The prevalence and phenotype/genotype characteristics of USH in Ireland have, as yet, gone unreported. Understanding the genotype of Irish USH patients may guide clinical and genetic characterization facilitating access to existing/novel therapeutics.

Retinitis Pigmentosa: Current Clinical Management and Emerging Therapies

Retinitis pigmentosa (RP) comprises a group of inherited retinal dystrophies characterized by the degeneration of rod photoreceptors, followed by the degeneration of cone photoreceptors. As a result of photoreceptor degeneration, affected individuals experience gradual loss of visual function, with primary symptoms of progressive nyctalopia, constricted visual fields and, ultimately, central vision loss. The onset, severity and clinical course of RP shows great variability and unpredictability, with most patients already experiencing some degree of visual disability in childhood. While RP is currently untreatable for the majority of patients, significant efforts have been made in the development of genetic therapies, which offer new hope for treatment for patients affected by inherited retinal dystrophies. In this exciting era of emerging gene therapies, it remains imperative to continue supporting patients with RP using all available options to manage their condition. Patients with RP experience a wide variety of physical, mental and social-emotional difficulties during their lifetime, of which some require timely intervention. This review aims to familiarize readers with clinical management options that are currently available for patients with RP.

Photoreceptor function and structure in retinal degenerations caused by biallelic BEST1 mutations

The only approved retinal gene therapy is for biallelic RPE65 mutations which cause a recessive retinopathy with a primary molecular defect located at the retinal pigment epithelium (RPE). For a distinct recessive RPE disease caused by biallelic BEST1 mutations, a pre-clinical proof-of-concept for gene therapy has been demonstrated in canine eyes. The current study was undertaken to consider potential outcome measures for a BEST1 clinical trial in patients demonstrating a classic autosomal recessive bestrophinopathy (ARB) phenotype. Spatial distribution of retinal structure showed a wide expanse of abnormalities including large intraretinal cysts, shallow serous retinal detachments, abnormalities of inner and outer segments, and an unusual prominence of the external limiting membrane. Surrounding the central macula extending from 7 to 30 deg eccentricity, outer nuclear layer was thicker than expected from a cone only retina and implied survival of many rod photoreceptors. Co-localized however, were large losses of rod sensitivity despite preserved cone sensitivities. The dissociation of rod function from rod structure observed, supports a large treatment potential in the paramacular region for biallelic bestrophinopathies.

Fundus Photography Methodologies to Assess RP Patients

The development of fundus photography and imaging has improved our ability to diagnose and monitor inherited retinal degenerations. Nowadays, color fundus photography has become a staple in evaluating patients with retinitis pigmentosa (RP). Other important multimodal forms of fundus photography used today include red-free fundus photography, short-wavelength autofluorescence, and near-infrared autofluorescence. These photography methodologies provide valuable information on the natural history of disease progression, which in turn can lead to the identification of viable outcome measurements for current and future therapeutic trials. Further advances and developments in the field of fundus imaging will help in our understanding of RP and allied disorders.

Prevalence and associated factors of cystoid macular edema in children with early onset inherited retinal dystrophies

PURPOSE

To assess the prevalence of Cystoid macular edema (CME) in children with early onset retinal dystrophies (EORD) and to evaluate if there are associated factors and/or response to early treatment.

METHODS

Consecutive, retrospective case series. Medical records of patients, 18 years or younger, diagnosed with EORD were included in the study. Optic coherence tomography (OCT) scans, clinical and genetic characteristics as well as other associated factors were analyzed. Main outcome was the presence of CME on OCT scans.

RESULTS

One hundred and two children with EORD (aged 1-18 years, mean 9.7 ± 4.2) were recruited. OCT was performed in 60/102 and among them, 19/60 had CME (31.7%). The disease-causing gene was identified in 13 children with CME; autosomal-recessive inheritance was found in 88.3% of those with an identified genotype. Children with Usher syndrome had CME in 44.4% of the cases. Early treatment of CME resulted in variable response.

CONCLUSIONS

Our results show that 31.7% of children with EORD who underwent OCT have macular edema. CME prevalence was found to be relatively higher in children with Usher syndrome. Autosomal recessive was the most prevalent inheritance identified in the EORD group as well as in the CME group. Additional prospective research is needed to assess the efficacy of early CME treatment in pediatric EORD patients.

RPE65 c.353G>A, p.(Arg118Lys): A Novel Point Mutation Associated with Retinitis Pigmentosa and Macular Atrophy

Precise genetic diagnosis in RPE65-mediated retinitis pigmentosa (RP) is necessary to establish eligibility for genetic treatment with voretigene neparvovec: a recombinant adeno-associated viral vector providing a functional RPE65 gene. This case report aims to report a novel RP-related point mutation RPE65 c.353G>A, p.(Arg118Lys), a variant of uncertain significance associated with a severe clinical presentation and the striking phenotypic feature of complete macular atrophy. We report the case of a 40-year-old male with inherited retinal dystrophy, all features typical for the RPE65-associated RP, and marked macular atrophy. Genetic testing identified that the patient was a compound heterozygote in trans form with two heterozygous variants: RPE65 c.499G>T, p.(Asp167Tyr) and RPE65 c.353G>A, p.(Arg118Lys). Furthermore, short-wavelength and near-infrared autofluorescence patterns exhibited deficiencies specific to mutations in the visual cycle genes. To the best of our knowledge, RPE65 c.353G>A, p.(Arg118Lys) is the first described point mutation on this locus, among all other reported insertional mutations, currently classified as likely benign and of uncertain significance. We concluded that this variant contributed to the pathological phenotype, demonstrating its significance clearly to be reclassified as likely pathogenic. This being the case, patients with this specific variant in homozygous or compound heterozygous form would be likely candidates for genetic treatment with voretigene neparvovec.

Non-vasogenic cystoid maculopathies

Besides cystoid macular edema due to a blood-retinal barrier breakdown, another type of macular cystoid spaces referred to as non-vasogenic cystoid maculopathies (NVCM) may be detected on optical coherence tomography but not on fluorescein angiography. Various causes may disrupt retinal cell cohesion or impair retinal pigment epithelium (RPE) and Müller cell functions in the maintenance of retinal dehydration, resulting in cystoid spaces formation. Tractional causes include vitreomacular traction, epiretinal membranes and myopic foveoschisis. Surgical treatment does not always allow cystoid space resorption. In inherited retinal dystrophies, cystoid spaces may be part of the disease as in X-linked retinoschisis or enhanced S-cone syndrome, or occur occasionally as in bestrophinopathies, retinitis pigmentosa and allied diseases, congenital microphthalmia, choroideremia, gyrate atrophy and Bietti crystalline dystrophy. In macular telangiectasia type 2, cystoid spaces and cavitations do not depend on the fluid leakage from telangiectasia. Various causes affecting RPE function may result in NVCM such as chronic central serous chorioretinopathy and paraneoplastic syndromes. Non-exudative age macular degeneration may also be complicated by intraretinal cystoid spaces in the absence of fluorescein leakage. In these diseases, cystoid spaces occur in a context of retinal cell loss. Various causes of optic atrophy, including open-angle glaucoma, result in microcystoid spaces in the inner nuclear layer due to a retrograde transsynaptic degeneration. Lastly, drug toxicity may also induce cystoid maculopathy. Identifying NVCM on multimodal imaging, including fluorescein angiography if needed, allows guiding the diagnosis of the causative disease and choosing adequate treatment when available.

EFFECT OF ORAL CARBONIC ANHYDRASE INHIBITOR ON CYSTOID MACULAR EDEMA ASSOCIATED WITH RETINITIS PIGMENTOSA: an OCT and OCT angiography study

PURPOSE

To investigate the factors associated with visual improvement in response to oral carbonic anhydrase inhibitors (CAIs) and the occurrence of microvascular changes in patients with retinitis pigmentosa-associated cystoid macular edema (RP-CME).

METHODS

This retrospective cohort study included 59 eyes from 39 patients with RP-CME who underwent at least 3 month of oral CAI treatment. The eyes were divided into responding and non-responding groups based on optical coherence tomography (OCT) criteria (resolution of cyst and reduction of foveal or parafoveal volume). All eyes were assessed before and after treatment using OCT and OCT angiography.

RESULTS

Thirty-three eyes (55.9%) demonstrated a positive response to treatment, and 26 eyes (44.1%) did not. Compared with non-responding eyes, responding eyes had a significantly higher frequency of multilayer CME than CME limited to the inner nuclear layer (P = 0.016). Subgroup analysis within the responding group revealed that improvements in visual acuity were more likely in eyes with fovea-involving CME and a higher baseline external limiting membrane and ellipsoid zone width. Microvascular parameters showed no significant changes after treatment.

CONCLUSION

Eyes with CME extending to the ONL or central fovea, and higher initial photoreceptor integrity may be prognostic factors associated with structural and functional improvements after CAI treatment. Early treatment of multilayer CME with foveal involvement seems to be crucial in preventing irreversible photoreceptor damage.

Prevalence and associated relating factors in patients with hereditary retinal dystrophy: a nationwide population-based study in Taiwan

OBJECTIVE

To investigate the prevalence, incidence and relating factors that are associated with hereditary retinal dystrophy (HRD) in Taiwan from 2000 to 2013.

DESIGN, SETTING AND PARTICIPANTS

This is a nationwide, population-based, retrospective case-control study using National Health Insurance Database. Study groups are patients with HRD as case group; age-matched patients without any diagnosis of HRD as control group. We enrolled 2418 study subjects, of which 403 were HRD patients. Important relating factors such as hypertension, diabetes, coronary artery disease, autoimmune disease, cancer, liver cirrhosis, chronic kidney disease, stroke, hyperlipidaemia, asthma, depression and dementia are also included.

EXPOSURE

Patients diagnosed with HRD were retrieved from National Health Insurance Database.

MAIN OUTCOMES AND MEASURES

OR calculated between the relating factors and HRD for objects and stratified by age and sex group between 2000 and 2013.

RESULTS

Four hundred and three patients were included in the study group and 2015 in the control group. The incidence of HRD was 3.29/100 000, and the prevalence of HRD was 40.5/100 000 persons. The tendency of study group to have more cataract, cystoid macula oedema (CME) as compared with the control group. Among the subgroup with comorbidities, the relating factors such as hypertension, diabetes and chronic kidney disease was significantly higher among HRD patients with age 55 and above.

CONCLUSIONS

74% of the diagnosed HRD are retinitis pigmentosa. Population-based data suggested an increased incidence of cataract in younger patients, whereas older HRD patients are more susceptible to develop CME. Further work is needed to elucidate the mechanism between these ophthalmological disorders and HRD.

Frequency of cystoid macular edema and vitreomacular interface disorders in genetically solved syndromic and non-syndromic retinitis pigmentosa

PURPOSE

Retinitis pigmentosa (RP) corresponds to a group of inherited retinal disorders where progressive rod-cone degeneration is observed. Cystoid macular edema (CME) and vitreomacular interface disorders (VMID) are known to complicate the RP phenotype, challenging an age-old concept of retained central visual acuity. The reported prevalence of these changes varies greatly among different studies. We aim to describe the frequency of CME and VMID and identify predictors of these changes in a cohort of Caucasian patients with genetically solved syndromic (sRP) and non-syndromic RP (nsRP).

METHODS

Cross-sectional study of patients with genetically solved sRP or nsRP. Genetic testing was clinically oriented in all probands and coordinated by a medical geneticist. The presence/absence of CME and VMIDs such as epiretinal membrane (ERM), vitreomacular traction (VMT), lamellar hole (LH), macular hole (MH), and macular pseudohole (MPH), and the integrity of the neurosensory retina and retinal pigment epithelium were evaluated in individual macular SD-OCT b-scans. Mixed-effects regression analysis models were used to identify significant predictors of BCVA, CME, and VMID. Significance was considered at α < 0.05.

RESULTS

We included 250 eyes from 125 patients. Mean age was 44.9 ± 15.7 years and 55.2% were male. Eighty-eight patients had nsRP and 37 had sRP. Median BCVA was 0.5 (0.2-1.3) logMAR. CME was found in 17.1% of eyes, while ERM was found in 54.3% of eyes. The frequency of CME (p = 0.45) and ERM (p = 0.07) did not differ between sRP and nsRP patients, nor across different inheritance patterns. Mixed-effects univariate linear regression identified age (p = 0.04), cataract surgery (p < 0.01), and loss of integrity of outer retinal layers (p < 0.01) as significant predictors of lower visual acuity, while increased foveal thickness (p < 0.01) and the presence of CME (p = 0.04) were predictors of higher visual acuity. On mixed-effects multivariable analysis, only increased foveal thickness was significantly associated with better visual acuity (p < 0.01).

CONCLUSION

We found that the burden of ERM and CME in RP patients is high, highlighting the importance of screening for these potentially treatable conditions to improve the quality of life of RP patients.

SD-OCT analysis in syndromic and non-syndromic forms of retinitis pigmentosa due to USH2A gene mutations

INTRODUCTION

This study aims to analyze macular structure by using SD-OCT in a cohort of patients affected by autosomal recessive retinitis pigmentosa and Usher syndrome, due to genetic variants in USH2A gene, and to correlate OCT parameters with functional and genetic data.

METHODS

The subjects of this study were 92 patients, 46 syndromic (Ush2) and 46 non-syndromic (arRP), with clinical and genetic diagnosis of USH2A-related retinal dystrophy, who underwent a complete ophthalmic examination and spectral domain OCT analysis. The study focused on evaluating the differences between the two groups in the following parameters: best corrected visual acuity (BCVA), ellipsoid zone width (EZ), presence of epiretinal membrane (ERM) and cystic macular lesions (CML). Variants in USH2A gene were divided in 3 categories, according to the expected impact (low/high) at protein level of the different variants on each allele.

RESULTS

BCVA and EZ width were significantly lower in Ush2 than in arRP patients (p < 0.0001 and p = 0.001). ERM was detected in 34.8% (16/46) of arRP patients and in 65.2% (30/46) of Ush2 patients (p = 0.003). CML was detected in 17.4% (8/46) of arRP patients and 30.4% (14/46) of Ush2 patients (p = 0.14). The allelic distribution was statistically different (p = 0.0003) by dividing the two diseases: for Ush2 patients it was 45.7% (high/high), 39.1% (low/high) and 15.2% (low/low); for arRP patients it was 8.7% (high/high), 56.5% (low/high) and 34.8% (low/low). The severity class of the variants significantly affected VA and EZ width parameters (p = 0.004 and p = 0.002, respectively).

CONCLUSION

Retinal disease, as evaluated by means of SD-OCT, shows more advanced degeneration signs in the syndromic than the non-syndromic form of retinal dystrophy related to USH2A gene. Variant types and allelic profiles are determining factors for the onset of syndromic features. However, since the three allelic profiles can be found in both Usher and RP patients, other factors must necessarily play a determining role.

Flap technique-assisted surgeries for advanced retinitis pigmentosa complicated with macular hole: a case report and literature review

Background

Full-thickness macular hole (FTMH) is a rare complication in retinitis pigmentosa (RP) patients and may increase intraoperative challenges. Furthermore, lens capsular flap transplantation and inverted internal limiting membrane (ILM) flap were reported to close complicated FTMH successfully. Here, we present a case of bilateral advanced RP complicated by a FTMH treated with a novel lens capsular flap transplantation and inverted internal limiting membrane flap.

Case presentation

A 46-year-old presented to our hospital with a complaint of progressively blurred vision and metamorphopsia in both eyes. Spectral-domain optical coherence tomography revealed a FTMH with retinoschisis in the right eye and another FTMH in the left eye. ILM peeling with inverted ILM flap technique was performed on the right eye and ILM peeling with anterior lens capsular flap technique was performed on the left eye. Post-operative follow-up showed successful closure of the FTMH and improved vision in both eyes.

Conclusions

In our present case, flap-assisted techniques for retinitis pigmentosa with macular hole result in excellent visual and anatomic outcomes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12886-021-02082-3.

Descriptive Study of a Cohort of 488 Patients with Inherited Retinal Dystrophies

Purpose

To analyze the distribution of inherited retinal diseases (IRDs), describe the clinical characteristics of patients, and determine the percentages of patients with genetic diagnosis in the Castilla y Leon region of Spain.

Methods

All patients with an IRD seen in the two major referral units of Castilla y Leon during a 20-year period were included. The ages at symptom onset, diagnosis, and the last visit; sex; family history; history of consanguinity; type of inheritance; status of the fundus and electroretinogram findings; lens and macular status, visual acuity; and visual field data were recorded. Patients were divided into those with retinitis pigmentosa (RP) and all others. Gene mutations were gathered when available.

Results

Four hundred eighty-eight patients with IRDs were studied: 216 (44.26%) with RP of which 34 (15.74%) had syndromic diseases, and 272 had other conditions being 161 (59,19%) macular dystrophies. The mean delay in diagnosis was 6–16.2 years respectively. For the RP group the mean age at the last visit was 47.96±17,26; mean age of cataract surgery was 48.30 ± 12.01 years; and the foveal area was preserved in 74 (35.07%) patients, atrophic in 101 (47.87%), and edematous in 36 (17.06%). A genetic study had been performed in 58 (26.85%) of patients with RP and 71 (26,1%) of the rest, being indeterminate in 17 (29.31%) out of RP group and 20 (28.16%) out of the others.

Conclusion

Clinical characteristics are comparable to other published series. There is a significant delay in diagnosis. The number of patients with IRDs and available genetic diagnosis, thus being possible candidates for undergoing personalized treatments including gene therapy in our region is low and must be improved.

Choroidal Vascularity Features in Patients with Choroideremia and Cystoid Spaces

Cystoid spaces (CSs) are a common retinal finding in choroideremia (CHM) patients. The aim of this study was to analyze the vascular features of the choroid associated with the presence of CSs in patients with confirmed genetic diagnosis of CHM. A total of 33 patients (33 eyes) were enrolled in this retrospective cross-sectional study and divided into two groups based on the presence (17 eyes) or absence (16 eyes) of CSs. Choroidal features were evaluated on spectral-domain optical coherence tomography including subfoveal choroidal thickness (CT), total choroidal area (TCA), luminal choroidal area (LCA), and stromal choroidal area (SCA). The choroidal vascularity index (CVI) was then calculated in all study eyes. All structural choroidal parameters were calculated both on the entire length of the B-scan and in the central subfoveal 1500 μm. The average age was 37.3 ± 11.6 and 31.4 ± 16.7 years (p = 0.25) and mean logMAR best-corrected visual acuity was 0.11 ± 0.20 and 0.20 ± 0.57 (p = 0.54) in the CHM groups with and without CSs, respectively. There were no significant differences in subfoveal CT, and TCA, LCA, SCA, and CVI evaluated on either the entire scan or in the central 1500 μm (all p > 0.05). All choroidal vasculature parameters exhibited no significant differences between CHM eyes with and without CSs. Our results suggest that the choroid may not be involved in the development of CSs in patients with CHM.

Longitudinal Changes of Macular Curvature in Patients with Retinitis Pigmentosa

Purpose

To investigate the longitudinal changes of the macular curvature in eyes with retinitis pigmentosa (RP) and to determine the factors associated with the changes.

Methods

We reviewed the medical charts of 107 RP patients, for whom the axial length of their right eyes ranged from 21.5 to 26.0 mm and who had had been followed by spectral-domain optical coherence tomography (OCT). The OCT images at the initial and the most recent examinations were compared. The mean curvature of Bruch's membrane within 6 mm of the central macula obtained from the OCT images was evaluated as the mean macular curvature index (MMCI). Changes in the MMCI and their relationships with other clinical factors, including the ellipsoid zone (EZ) width, were assessed.

Results

The MMCI decreased significantly in the vertical OCT images, from –15.47 × 10⁻⁵ µm⁻¹ to –16.36 × 10⁻⁵ µm⁻¹ (P = 0.008) during the mean observation period of 3.4 ± 1.4 years (mean ± SD). This indicated that the macular shape became more concave. The change to a steeper shape was more prominent in eyes with less photoreceptor degeneration and for which the EZ width was preserved at >2000 µm. In three eyes, the MMCI increased markedly by >5 × 10⁻⁵ µm⁻¹, and this was accompanied by absorption of the macular edema.

Conclusions

The macular curvature in RP eyes becomes more concave in eyes with preserved EZ width.

Translational Relevance

Longitudinal changes of the macular curvature in RP should be considered in future therapies, such as the implantation of the retinal prosthesis.

Optical coherence tomography in the evaluation of retinitis pigmentosa

BACKGROUND

Optical coherence tomography (OCT) is a non-invasive imaging test that provides easily obtainable and highly reproducible cross-sectional images of the retina. Improved modalities of the OCT that are capable of providing high quality images of not only the retina, but also the deeper structures and vasculature have been developed, including swept-source OCTs and OCT angiography.

MATERIALS AND METHODS

Review.

RESULTS

The use of OCT in the monitoring of retinitis pigmentosa has been well described and numerous signs of disease progression have been studied. Notably among them are the detection of changes to retinal thickness, the ellipsoid zone, the vasculature on OCT angiography, and cystoid macular edema.

CONCLUSION

In this review, we discuss the multiple applications of OCT as a tool in the monitoring of retinitis pigmentosa and its potential use as an outcome measurement in current and future therapeutic endeavors.

Anti-VEGF and Retinal Dystrophies

The therapeutic approach based on anti-vascular endothelial growth factor (anti-VEGF) molecules can be used to treat two important complications of retinal dystrophies: choroidal neovascularization and macular edema. The macular involvement in retinal dystrophies can lead to further visual deterioration in patients at a young age and already affected by functional limitations. The study reports the effect of anti-VEGF treatment in several subforms of retinal dystrophies, critically discussing advantages and limitations.

Wide-field Ophthalmic Space-Division Multiplexing Optical Coherence Tomography

High-speed ophthalmic optical coherence tomography systems are of interest because they allow rapid, motion-free, and wide-field retinal imaging. Space-division multiplexing optical coherence tomography (SDM-OCT) is a high-speed imaging technology which takes advantage of the long coherence length of microelectromechanical vertical cavity surface emitting laser (MEMs VCSEL) sources to multiplex multiple images along a single imaging depth. We demonstrate wide-field retinal OCT imaging, acquired at an effective A-scan rate of 800,000 A-scans/sec with volumetric images covering up to 12.5 mm × 7.4 mm on the retina acquired in less than 1 second. A clinical feasibility study was conducted to compare the ophthalmic SDM-OCT with commercial OCT systems, illustrating the high-speed capability of SDM-OCT in a clinical setting.

Vitreo-macular interface disorders in retinitis pigmentosa

PURPOSE

To investigate the prevalence and progression of vitreo-macular interface disorders (VMID) phenotypes and their natural history in retinitis pigmentosa (RP).

METHODS

A total of 257 eyes of 145 RP patients with VMID were retrospectively evaluated. Patients were divided according to the VMID subtypes into epiretinal membranes (ERMs), vitreo-macular traction (VMT) group, and macular hole (MH). Serial eye-tracked spectral-domain optical coherence tomography (SD-OCT) and best-corrected visual acuity (BCVA) changes were analyzed for a mean follow-up of 36.95 months. The status of posterior vitreous cortex was also considered. A control group of 65 eyes belonging to 65 RP patients with no macular changes was also recruited.

RESULTS

VMID and control groups had the same baseline BCVA (0.50 vs 0.44 LogMAR) and did not differ in terms of phakic status. Different VMID groups had similar BCVA at baseline (p = 0.98). ERM represented the most prevalent disorder (207/257 eyes, 80.5%), followed by 35/257 (13.6%) VMT, and 15/257 Lamellar MH (LMH) eyes (5.8%). There were no cases of full thickness MH. Throughout the 36.9 months of follow-up, BCVA decreased an average 0.09 LogMAR from 0.31 to 0.4 in VMID patients and 0.01 in controls. VMID subgroup analysis showed a significant BCVA decrease in ERM patients (- 20.29%, p < 0.001), while VMT and LMH did not change significantly. Foveal thickness also remained stable over time. Complete PVD was present in 11 eyes in ERM, VMT, and LMH.

CONCLUSIONS

Our study confirms the high prevalence of VMID in RP patients; however, only ERMs determined a significant loss of vision over 24 months. The high prevalence of VMID in RP patients suggests that macular alteration other than edema represents part of disease spectrum.

Comparison of 5-year progression of retinitis pigmentosa involving the posterior pole among siblings by means of SD-OCT: a retrospective study

Background

The aim of this study is to analyze and compare the progression of photoreceptor atrophy among siblings affected by retinitis pigmentosa by means of spectral SD-OCT.

Methods

Fifty three eyes of 27 patients belonging to 12 family clusters were analyzed. To assess the annual progression rate of photoreceptor atrophy, the ellipsoid zone (EZ) line was measured in OCT sections through the fovea. We used multivariate generalized mixed effects to model the rate of progression and its relation to the initial ellipsoid zone line width.

Results

During our 4.84 years (± 1.44) mean follow up time (range 3–7) 53 eyes were examined. The ellipsoid zone line width declined with a yearly average rate of 76.4 μm (4.16% / year) (p-value < 0.0001). Progression rates were poorly correlated within family clusters (p-value = 0.23) and showed statistical difference between affected siblings (p-value = 0.007). There was no correlation between inter-familiar progression rate and mode of inheritance (p-value = 0.98) as well as between age and ellipsoid zone line width among siblings (p-value = 0.91).

Conclusion

RP could be extremely heterogeneous even among siblings: an accurate and sensitive method to follow the progression of the disease is fundamental for future development of clinical trials and therapy strategies.

INTRAVENOUS IMMUNOGLOBULIN IN THE TREATMENT OF JUVENILE RETINITIS PIGMENTOSA-ASSOCIATED CYSTOID MACULAR EDEMA AND UVEITIS

PURPOSE

To evaluate the efficacy of intravenous immunoglobulin in the treatment of cystoid macular edema and uveitis caused by juvenile retinitis pigmentosa in a woman interested in planning a pregnancy.

METHODS

Descriptive case report. A 25-year-old woman with retinitis pigmentosa presented with decreased visual acuity, interested in a second opinion.

RESULTS

Intravenous immunoglobulin therapy was begun at 2-week intervals. Visual acuity improved from 20/100 to 20/70 by 6 weeks, where it stabilized for the remaining year. Serial optical coherence tomography imaging revealed marked improvement in cystoid macular edema after 2 treatments of intravenous immunoglobulin at 2 weeks of follow-up, with complete resolution noted at 4 months, a finding that persisted at 1 year of follow-up.

CONCLUSION

Our findings support the use of intravenous immunoglobulin as a therapeutic option for the resolution of cystoid macular edema and management of uveitis secondary to juvenile retinitis pigmentosa.

Assessment of Central Visual Function in Patients with Retinitis Pigmentosa

In order to clarify the disease progression in retinitis pigmentosa (RP) and its related factors, reliable data on the changes in central visual function in RP are needed. In this longitudinal study, we examined 118 patients who were diagnosed with typical RP. Visual acuity (VA), visual field using a Humphrey Field Analyzer with the central 10-2 SITA-Standard program, and optical coherence tomography measurements were obtained. The slopes, which were derived from serial values of mean deviation (MD), macular sensitivity (MS), or foveal sensitivity (FS) obtained for each eye by a linear mixed model, were used for analysis. MS and FS were calculated as the average retinal sensitivity of 12 and 4 central points respectively. There were statistically significant interactions of times with levels of the central subfield thickness (CST) on the slopes of MS and FS. Compared to the eyes without macular complications, the eyes with macular complications had steeper MD, MS and FS slopes, and this interaction was no significant, but marginal trend for the MS or FS slope (P = 0.10, 0.05, respectively). The central retinal sensitivity (i.e., MS and FS) slopes calculated were effective indices of the progression of central visual function in RP.

Efficacy of additional topical betamethasone in persistent cystoid macular oedema after carbonic anhydrase inhibitor treatments in retinitis pigmentosa

Objective

We investigated the efficacy of additional topical betamethasone in persistent cystoid macular oedema (CMO) after carbonic anhydrase inhibitors (CAIs) therapy.

Methods and analysis

This retrospective cohort study included 16 eyes of 10 patients with retinitis pigmentosa (RP). All patients were previously administered CAI for at least 3 months to treat CMO secondary to RP and lacking an effective reduction (≥11%) of central foveal thickness (CFT). We administered topical 0.1% betamethasone daily in each affected eye following a preceding course of the CAI medication as a first treatment. CMO was diagnosed using spectral-domain optical coherence tomography. CFT was regarded as the average of vertical and horizontal foveal thickness. Best-corrected visual acuity (BCVA) and intraocular pressure (IOP) were obtained from patient medical records. We compared the CFT and BCVA between baseline and the average of 1-3, 5-7, 10-14 and 16-20 months period.

Results

In treatments with brinzolamide in 14 eyes, dorzolamide in 2 eyes and bromfenac in 2 eyes, CFT effectively decreased in 12 of 16 eyes (81%). CFT decreased significantly in 1-3 months (326±102 µm; n=16; P=0.029) and 5-7 months (297±102 µm; n=12; P=0.022) compared with baseline but not within 10-14 months (271±96 µm; n=9; P=0.485) or 16-20 months (281±134 µm; n=9; P=0.289). There were no significant intergroup differences in BCVA throughout the study. Betamethasone treatment was stopped in three patients because of IOP elevation.

Conclusion

Our data suggested that additional betamethasone might improve treatments for persistent CMO. Topical steroids could be an alternative option for managing persistent CMO in RP.

Ganglion cell-inner plexiform layer and retinal nerve fibre layer changes within the macula in retinitis pigmentosa: a spectral domain optical coherence tomography study

PURPOSE

To investigate how macular ganglion cell-inner plexiform layer (GCIPL) and retinal nerve fibre layer (RNFL) thicknesses within the macula change with retinitis pigmentosa (RP) severity.

METHODS

Spectral domain optical coherence tomography (SD-OCT) was used to examine 177 patients with RP and 177 normal controls. An optical coherence tomography (OCT) line scan was used to grade RP severity. Retinitis pigmentosa (RP) was categorized as more advanced if there was no identifiable inner segment ellipsoid (ISe) band (NISE) and as less advanced if an ISe band could be identified and peripheral loss of ISe was apparent (IISE). Ganglion cell-inner plexiform layer (GCIPL) and RNFL thicknesses were manually measured on OCT images and analysed. Pearson's correlation analyses were used to examine correlations between GCIPL thickness, RNFL thickness, visual acuity (VA) and visual field extent in patients and controls.

RESULTS

Ganglion cell-inner plexiform layer (GCIPL) was significantly thicker in IISE than in control eyes (p < 0.001), but significantly thinner in NISE than in IISE eyes (p < 0.001) in both horizontal and vertical OCT scans. Retinal nerve fibre layer (RNFL) was significantly thicker in eyes with IISE and NISE than in control eyes in both horizontal and vertical meridians (all p < 0.001). Ganglion cell-inner plexiform layer (GCIPL) thickness showed a weak positive correlation with vision, and RNFL thickness showed a weak negative correlation with vision and visual field extent.

CONCLUSION

Based on these results, the inner retina, including the GCIPL and RNFL, maintains its gross integrity longer than the photoreceptor layer in RP. Additionally, thickening of the inner retina may have some functional implications in patients with RP.

Intravitreal Triamcinolone Acetonide in Refractory Pseudophakic Cystoid Macular Edema: Functional and Anatomic Results

PURPOSE

To evaluate safety and efficacy of intravitreal triamcinolone acetonide (TAAC) injections in the treatment of refractory pseudophakic cystoid macular edema (CME).

METHODS

Seven eyes of six patients (age range: 50-74) with pseudophakic CME resistant to standard treatment received intravitreal injections of 4 mg of TAAC with all vehicle. Mean preinjection duration of CME was 18.3 months. A mean of 2.1+/-1.2 (range 1 to 4) treatments were performed in four eyes (57.1 %) when visual acuity deteriorated towards baseline levels. Visual acuity assessment, optical coherence tomography (OCT), and fluorescein angiography (FFA) were performed pre- and postoperatively to evaluate results of TAAC injections. Intraocular pressure (IOP) and complications related to treatment were assessed.

RESULTS

After 11.1+/-3.9 months, mean best-corrected visual acuity (BCVA) increased (p =0.019) from 20/132 to a best value of 20/38. Mean macular thickness decreased from 517.29+/-146.98 mm to a best value of 263.71+/-83.13 mm (p=0.0018). Area of fluorescein leakage decreased (p<0.0001) from 11.84+/-0.93 mm2 at baseline to a minimal value of 3.86+/-0.98 mm2. The anatomic and functional improvement appeared after 1 month from the intravitreal injection and persisted through at least 3 months of follow-up. At the end of follow-up BCVA, macular thickness, and area of fluorescein leakage did not differ from baseline. Four eyes (57.1 %) developed IOP values higher than 21 mmHg, controlled by topical treatment. Two patients developed an endophthalmitis-like reaction.

CONCLUSIONS

Intravitreal TAAC was relatively safe and effective in resistant cases of pseudophakic CME with a temporary beneficial effect on visual acuity and macular edema.

Spectral domain optical coherence tomography changes following intravitreal dexamethasone implant, Ozurdex® in patients with uveitic cystoid macular edema

Purpose:

To correlate the structural and functional changes following intravitreal injection of dexamethasone 0.7 mg (Ozurdex^®) implant in patients with recalcitrant uveitic cystoid macular edema (CME).

Materials and Methods:

In a prospective, interventional, nonrandomized study, 30 eyes (27 patients) with uveitic CME received Ozurdex^® implant and were followed-up for 24 weeks at periodic intervals to monitor structural alterations seen on spectral domain optical coherence tomography (SD-OCT). The outcome measures included change in central macular thickness (CMT) and best-corrected visual acuity (BCVA) as well as structural alterations seen on OCT such as change in the height of cystoid spaces (CSs) and sub-foveal serous retinal detachment (SSRD). The integrity of external limiting membrane and inner-outer segment junction was assessed at baseline and follow-up visits.

Results:

Mean age of the patients was 46.09 ± 15.66 years. The mean CMT decreased by 96 μm at 1-day, 231.64 μm at 1-week, 254.21 μm at 4 weeks and 249.14 μm at 12 weeks (P < 0.001) compared with baseline. BCVA improved from a baseline mean of 0.62 LogMAR units to 0.49 on day 1 to 0.31 at 24 weeks (P < 0.001). A decrease in the mean height of CS, that is, 133.28 μm from a baseline of 317.71 μm was noted on the 1^st day (P < 0.001). 4 eyes demonstrated the presence of CS at 4 weeks, 1 eye at 6 weeks and 3 eyes at 12 weeks. At baseline, 16 eyes (53.33%) demonstrated the presence of SSRD. Among these, 11 eyes showed resolution of SSRD on day 1. SSRD resolved in all patients at 4 weeks and was maintained up to 24 weeks.

Conclusions:

Ozurdex^® implant improves the visual outcome of patients with recalcitrant uveitic CME. Reversibility of retinal changes may be possible following treatment with dexamethasone implant. Thus final visual outcome may be independent of pretreatment CMT, the height of CS or SSRD.

Retinitis pigmentosa-associated cystoid macular oedema: pathogenesis and avenues of intervention

Hereditary retinal diseases are now the leading cause of blindness certification in the working age population (age 16–64 years) in England and Wales, of which retinitis pigmentosa (RP) is the most common disorder. RP may be complicated by cystoid macular oedema (CMO), causing a reduction of central vision. The underlying pathogenesis of RP-associated CMO (RP-CMO) remains uncertain, however, several mechanisms have been proposed, including: (1) breakdown of the blood-retinal barrier, (2) failure (or dysfunction) of the pumping mechanism in the retinal pigment epithelial, (3) Müller cell oedema and dysfunction, (4) antiretinal antibodies and (5) vitreous traction. There are limited data on efficacy of treatments for RP-CMO. Treatments attempted to date include oral and topical carbonic anhydrase inhibitors, oral, topical, intravitreal and periocular steroids, topical non-steroidal anti-inflammatory medications, photocoagulation, vitrectomy with internal limiting membrane peel, oral lutein and intravitreal antivascular endothelial growth factor injections. This review summarises the evidence supporting these treatment modalities. Successful management of RP-CMO should aim to improve both quality and quantity of vision in the short term and may also slow central vision loss over time.

Novel grading system for quantification of cystic macular lesions in Usher syndrome

BACKGROUND

To evaluate novel grading system used to quantify optical coherence tomography (OCT) scans for cystic macular lesions (CML) in Usher syndrome (USH) patients, focusing on CML associated alterations in MOY7A and USH2A mutations.

METHODS

Two readers evaluated 76 patients' (mean age 42 ± 14 years) data prospectively uploaded on Eurush database. OCT was used to obtain high quality cross-sectional images through the fovea. The CML was graded as none, mild, moderate or severe, depending on the following features set: subretinal fluid without clearly detectable CML boundaries; central macular thickness; largest diameter of CML; calculated mean of all detectable CML; total number of detectable CML; retinal layers affected by CML. Intra-and inter-grader reproducibility was evaluated.

RESULTS

CML were observed in 37 % of USH eyes, while 45 % were observed in MYO7A and 29 % in USH2A cases. Of those with CML: 52 % had mild, 22 % had moderate and 26 % had severe changes, respectively. CML were found in following retinal layers: 50 % inner nuclear layer, 44 % outer nuclear layer, 6 % retinal ganglion cell layer. For the inter-grader repeatability analysis, agreements rates for CML were 97 % and kappa statistics was 0.91 (95 % CI 0.83-0.99). For the intra-grader analysis, agreement rates for CML were 98 %, while kappa statistics was 0.96 (95 % CI 0.92-0.99).

CONCLUSIONS

The novel grading system is a reproducible tool for grading OCT images in USH complicated by CML, and potentially could be used for objective tracking of macular pathology in clinical therapy trials.

Application of different imaging modalities for diagnosis of Diabetic Macular Edema: A review

Diabetic Macular Edema (DME) is caused by accumulation of extracellular fluid from hyperpermeable capillaries within the macula. DME is one of the leading causes of blindness among Diabetes Mellitus (DM) patients. Early detection followed by laser photocoagulation can save the visual loss. This review discusses various imaging modalities viz. biomicroscopy, Fluorescein Angiography (FA), Optical Coherence Tomography (OCT) and colour fundus photographs used for diagnosis of DME. Various automated DME grading systems using retinal fundus images, associated retinal image processing techniques for fovea, exudate detection and segmentation are presented. We have also compared various imaging modalities and automated screening methods used for DME grading. The reviewed literature indicates that FA and OCT identify DME related changes accurately. FA is an invasive method, which uses fluorescein dye, and OCT is an expensive imaging method compared to fundus photographs. Moreover, using fundus images DME can be identified and automated. DME grading algorithms can be implemented for telescreening. Hence, fundus imaging based DME grading is more suitable and affordable method compared to biomicroscopy, FA, and OCT modalities.

Long-term Surgical Outcomes of Epiretinal Membrane in Patients with Retinitis Pigmentosa

Macular complications such as an epiretinal membrane (ERM), a cystoid macular edema and a macular hole lead to unexpected central vision impairment especially for patients with retinitis pigmentosa (RP). To evaluate the long-term surgical outcomes of pars plana vitrectomy (PPV) for ERM in patients with RP, we retrospectively reviewed the charts of a consecutive series of 10 RP patients who underwent PPV for ERM at Kyushu University Hospital. Visual acuity (VA) testing, a fundus examination, and an optical coherence tomography (OCT) analysis were conducted. The standard PPV using three sclerotomies was performed for ERM. PPV was performed in 12 eyes of 10 patients. One eye was excluded from the outcome assessment due to short period observation (18 months). There was no significantly deleterious change from the baseline to final VA between the operation eyes and the fellow eyes (P = 0.19). Moreover, morphological improvement was obtained in 9 of 11 eyes based on OCT. Our present data suggest that PPV may be tolerable in the management for ERM in RP patients over the long-term. Furthermore, the appearance of the ellipsoid zone was an important factor in the prediction of visual outcome and determination of surgical indication.

Comparison of topical dorzolamide and ketorolac treatment for cystoid macular edema in retinitis pigmentosa and Usher's syndrome

PURPOSE

To investigate the topical effect of dorzolamide versus ketorolac on retinitis pigmentosa (RP) and Usher's syndrome (US) macular edema.

METHODS

Prospective, randomized and interventional study. A total of 28 eyes of 18 patients were included. Five eyes had US, 23 had RP. Fifteen eyes were allocated to ketorolac tromethamine 0.5% (4 drops daily regimen) and 13 eyes to dorzolamide hydrochloride 2% (3 drops daily regimen) treatment groups. Snellen's best-corrected visual acuity (BCVA), foveal thickness (FT) and foveal zone thickness (FZT) measured by Stratus® optical coherence tomography (OCT) were evaluated at baseline, 1, 3, 6 and 12 months after treatment.

RESULTS

Patients assigned to ketorolac had a baseline BCVA of 0.37 ± 0.17 logMAR which improved at the end of 1 year to 0.28 ± 0.16 (p = 0.02). Three eyes (20%) of 2 patients improved by 7 letters or more. Mean FT and FZT did not change significantly during the study follow-up. After 1 year of treatment, 4 eyes (27%) of 3 patients showed an improvement of at least 16% of FT and 11% of FZT. Patients assigned to dorzolamide had a baseline BCVA of 0.48 ± 0.34 logMAR which improved in the first 6 months (0.40 ± 0.30; p = 0.01), with a decrease at 1 year (0.42 ± 0.27; p = 0.20). Seven eyes (54%) of 5 patients had an improvement of 7 letters or more. Mean FT and FZT did not change significantly either. After 1 year of treatment, 3 eyes (23%) of 2 patients showed an improvement of at least 16% on FT and 11% on FZT.

CONCLUSIONS

RESULTS suggest that dorzolamide and ketorolac might improve visual acuity and therefore be of interest in selected cases. No relationship between retinal thickness fluctuation and visual acuity was found. Sample size was a limitation to the study.

Optical coherence tomography imaging of macular oedema

Macular oedema (ME) occurs in a wide variety of pathological conditions and accounts for different degrees of vision loss. Early detection of ME is therefore critical for diagnosis and therapeutic management. Optical coherence tomography (OCT) is a non-contact, diagnostic method that uses infrared light, which allows the analysis of the retinal structure by means of high-resolution tomographic cross sections. The identification, localisation, quantification and long-term follow-up of fluid collections are the most important capabilities of OCT. Since the introduction of OCT in clinical practice, it has become an invaluable diagnostic tool and different patterns of ME have been reported. The purpose of this manuscript is to review OCT profiles of ME according to the aetiology and describe what has been reported regarding intraretinal features in vivo.

The effect of an intravitreal dexamethasone implant for cystoid macular edema in retinitis pigmentosa: a case report and literature review

Intravitreal injection of a dexamethasone implant was used to treat a 24-year-old patient with retinitis pigmentosa (RP) who developed cystoid macular edema (CME) in both eyes that was refractory to oral acetazolamide and intravitreal bevacizumab treatment. After injection, best corrected visual acuity (BCVA) improved and central macular thickness decreased, but CME recurred in both eyes 6 months later. Although a second intravitreal dexamethasone implant injection resolved the CME and improved the BCVA, CME recurred in both eyes 6 months later. The intravitreal dexamethasone implant may be useful for CME in patients with RP, but its efficacy seems to be limited over time.

Intravitreal and subtenon depot triamcinolone as treatment of retinitis pigmentosa associated cystoid macular edema

We present a case of retinitis pigmentosa (RP) related cystoid macular edema (CME) refractory to oral acetazolamide and topical ketorolac that was treated with intravitreal and subtenon depot triamcinolone. A 32-year-old male with RP presented with complaints of bilateral decrease in visual acuity. His best-corrected visual acuity (BCVA) was 20/50 in the right eye and 20/100 in the left eye. After being informed of the available treatment options, the patient received bilateral intravitreal injection triamcinolone. The patient's BCVA improved to 20/40 in the right eye and 20/50 in the left eye and the CME was resorbed. However, 5 months after the injection in the left eye and two months in the right eye, visual acuity decreased due to recurrence of CME. We performed a second intravitreal injection in the left eye with improvement of visual and anatomic results, but we observed a recurrence of CME. Afterwards, we treated the patient with subtenon depot triamcinolone in both eyes, with the result that there was no recurrence after 4 months in OD or after 3 months in OS. We conclude that intravitreal and subtenon depot triamcinolone appear to provide at least temporary benefit in refractory CME as regards the improvement of visual acuity.

Cystoid macular edema in retinitis pigmentosa patients without associated macular thickening

PURPOSE

To describe the occurrence of cystoid macular edema (CME) in the setting of central foveal thickness (CFT) under 250 μm as measured by optical coherence tomography (OCT) in patients with retinitis pigmentosa (RP).

METHODS

Stratus OCT was used to measure CFT in a total of 90 eyes from 46 patients with RP. Cross-sectional OCT images were also evaluated for CME, which was defined as cystoid changes in the macula seen on at least two linear scans.

RESULTS

CME was identified in 13 of the 46 patients or in 22 of 90 eyes by OCT. In eyes with macular edema, CFT ranged from 224 to 718 μm (mean = 339 ± 137 μm). In eyes without macular edema, CFT ranged from 99 to 273 μm (mean = 184 ± 40 μm). Bilateral CME occurred in 9 of 13 patients (69%). CFT was considered "normal" in 7 of the 22 eyes (32%) with CME. Two patients had bilateral CME with normal CFTs, under 250 μm.

CONCLUSION

We demonstrate the occurrence of CME in RP patients without associated thickening, which has not been described. This concept likely is applicable to other diseases with retinal thinning.