Selective thinning of the perifoveal inner retina as an early sign of hydroxychloroquine retinal toxicity

Automated Evaluation of Ellipsoid Zone At-Risk Burden for Detection of Hydroxychloroquine Retinopathy

BACKGROUND

Screening for hydroxychloroquine (HCQ) retinopathy is crucial to detecting early disease. A novel machine-learning-based optical coherence tomography (OCT) biomarker, Ellipsoid Zone (EZ) At-Risk, can quantitatively measure EZ alterations and at-risk areas for progressive EZ loss in a fully automated fashion. The purpose of this analysis was to compare the EZ At-Risk burden in eyes with HCQ toxicity to eyes without toxicity.

METHODS

IRB-approved image analysis study of 83 subjects on HCQ and 44 age-matched normal subjects. SD-OCT images were reviewed for evidence of HCQ retinopathy. A ML-based, fully automatic measurement of the percentage of the macular area with EZ At-Risk was performed.

RESULTS

The mean age for HCQ subjects was 67.1 ± 13.2 years and 64.2 ± 14.3 years for normal subjects. The mean EZ At-Risk macular burden in the "toxic" group (n = 38) was significantly higher (10.7%) compared to the "non-toxic" group (n = 45; 2.2%; p = 0.023) and the "normal" group (1.4%; p = 0.012). Additionally, the amount of EZ At-Risk burden was significantly correlated with the HCQ dose based on the actual (p = 0.016) and ideal body weight (p = 0.033).

CONCLUSIONS

The novel biomarker EZ-At Risk was significantly higher in subjects with evidence of HCQ retinopathy as well as significantly associated with HCQ dose. This novel biomarker should be further evaluated as a potential screening tool for subjects on HCQ.

New proposal for a multimodal imaging approach for the subclinical detection of hydroxychloroquine-induced retinal toxicity in patients with systemic lupus erythematosus

OBJECTIVE

To compare multimodal structural and functional diagnostic methods in patients with systemic lupus erythematosus (SLE) treated with hydroxychloroquine, to identify the best complementary approach for detecting subclinical retinal toxicity.

METHODS

A cross-sectional, unicentric study was conducted on patients with SLE treated with hydroxychloroquine. Each patient underwent a comprehensive ophthalmic evaluation, comprising structural tests (spectral-domain optical coherence tomography (SD-OCT), en face OCT, en face OCT angiography (OCTA), fundus autofluorescence (FAF)) and functional tests (automated perimetry for visual field (VF) testing, multifocal electroretinography (mfERG)). A diagnosis of macular toxicity required the presence of abnormalities in at least one structural and functional test. The Kappa Concordance Index was used to assess the concordance among the different tests in detecting potential macular toxicity-associated alterations.

RESULTS

Sixty-six patients with SLE (132 eyes) were consecutively enrolled. Four (6.1%) patients developed subclinical hydroxychloroquine-induced retinal toxicity without visual acuity impairment. The proportion of abnormal results was 24% for both en face OCT and en face OCTA. Regarding functional analysis, VF was less specific than mfERG in detecting subclinical retinal toxicity (VF specificity 47.5%). En face OCT and en face OCTA structural findings showed better concordance, with a kappa index >0.8, and both identified the same cases of toxicity as FAF.

CONCLUSION

Although structural OCT and VF are frequently used to screen for hydroxychloroquine-induced retinal toxicity, our findings suggest that a combination of mfERG, en face OCT and en face OCTA could improve the diagnostic accuracy for subclinical retinal damage. This study emphasises the importance of a multimodal imaging strategy to promptly detect signs of hydroxychloroquine-induced retinal toxicity.

Outcomes of screening for hydroxychloroquine retinopathy at the Manchester Royal Eye Hospital: 2 years' audit

BACKGROUND

The Royal College of Ophthalmologists has produced guidelines for screening for hydroxychloroquine retinopathy. New imaging modalities had suggested an increased prevalence of retinopathy compared with previous reports. The aim of this study is to identify the real-life prevalence of hydroxychloroquine retinopathy in patients attending Manchester Royal Eye Hospital screening service over a 2-year period using The RCOphth diagnostic criteria.

METHODS

Data were collected prospectively from all patients attending Manchester Royal Eye Hospital hydroxychloroquine screening service over the audit period. Results of Humphrey visual field tests, spectral-domain optical coherence tomography and fundus autofluorescence were collected as well as data on dose, indication, duration of treatment, and additional risk factors. Cases were identified as having definite, possible, or no retinopathy based on the 2018 RCOphth criteria. The data are not publicly available due to information that could compromise research participant privacy and confidentiality but are available upon request from the corresponding author.

RESULTS

910 patients attended for screening. 566 were identified as being at risk of retinopathy (543 had been on treatment >5 years, 10 had renal impairment, 12 were on doses of >5 mg/kg/day, and one was concurrently on tamoxifen). The prevalence of HCQ retinopathy was 10/910 (1.09%) of all those screened, and 1.76% of those at risk (10/566). Six patients of those deemed at risk were identified as having definite hydroxychloroquine retinopathy, while four had possible retinopathy.

CONCLUSIONS

Our results show a prevalence of retinopathy largely consistent with reports from regional audits yet reveal a far lower estimate compared to previously reported figures.

Decreased perifoveal ganglion cell complex thickness - a first sign for macular damage in patients using hydroxychloroquine

Aim: To examine ganglion cell complex (GCC) thickness detected by optical coherence tomography (OCT) in patients using hydroxychloroquine (HCQ), without any structural and functional macular changes to evaluate the initial symptoms of macular toxicity for early diagnosis before clinical evaluation. Methods: Eighty eyes of forty patients (Group 1) and forty eyes of twenty healthy volunteer persons (Group 2) were included in the study. Detailed ophthalmologic and mydriatic fundus examination were applied to all patients and volunteers (controls). Spectral domain OCT, visual field (VF) and color vision test were performed. Measurements of macula thickness, GCC thickness (involving nerve fiber layer, ganglion cell layer and inner plexiform layer) and peripapillary retinal nerve fiber layer (RNFL) were performed with OCT. Patients with retinal pigment epithelial changes, VF paracentral scotoma and defected color vision were excluded from the planned study. Results: Perifoveal GCC layer thickness in all quadrants was significantly thinner in group 1 compared to group 2 (p=0.017, p=0.001, p=0.019, p=0.001). The mean global inferior hemifield and nasal quadrant RNFL thickness were lower than in the control groups (p=0,012, p=0,009, p=0,005, respectively). Conclusion: Changes in the thickness of nerve fiber layer and ganglion cell layer detected by optical coherence tomography can be thought to be used as a diagnostic aid for the early diagnosis of hydroxychloroquine-toxic maculopathy Abbreviations: GCC = Ganglion cell complex, OCT = Optical coherence tomography, HCQ = Hydroxychloroquine, BCVA = Best-corrected visual acuity, IOP = Intraocular pressure, VF = Visual field, RNFL = Retinal nerve fiber layer, SD OCT = Spectral-domain optical coherence tomography, mfERG = Multifocal electroretinogram, FAF = Fundus autofluorescence, IS/ OS = Inner segment-outer segment junction, SITA = Swedish Interactive Threshold Algorithm, RA = Rheumatoid arthritis, SLE = Systemic lupus erythematosus, SS = Sjogren syndrome.

The Impact of Systemic Medications on Retinal Function

This study will provide a thorough review of systemic (and select intravitreal) medications, along with illicit drugs that are capable of causing various patterns of retinal toxicity. The diagnosis is established by taking a thorough medication and drug history, and then by pattern recognition of the clinical retinal changes and multimodal imaging features. Examples of all of these types of toxicity will be thoroughly reviewed, including agents that cause retinal pigment epithelial disruption (hydroxychloroquine, thioridazine, pentosan polysulfate sodium, dideoxyinosine), retinal vascular occlusion (quinine, oral contraceptives), cystoid macular edema/retinal edema (nicotinic acid, sulfa-containing medications, taxels, glitazones), crystalline deposition (tamoxifen, canthaxanthin, methoxyflurane), uveitis, miscellaneous, and subjective visual symptoms (digoxin, sildenafil). The impact of newer chemotherapeutics and immunotherapeutics (tyrosine kinase inhibitor, mitogen-activated protein kinase kinase, checkpoint, anaplastic lymphoma kinase, extracellular signal-regulated kinase inhibitors, and others), will also be thoroughly reviewed. The mechanism of action will be explored in detail when known. When applicable, preventive measures will be discussed, and treatment will be reviewed. Illicit drugs (cannabinoids, cocaine, heroin, methamphetamine, alkyl nitrite), will also be reviewed in terms of the potential impact on retinal function.

Knowledge of Saudi Patients with Autoimmune Diseases about Hydroxychloroquine Toxicity: The Role of Physician-Patient Communication

This cross-sectional internet-based questionnaire aimed to assess the knowledge and experience of autoimmune disease patients in Saudi Arabia of the ocular effects of hydroxychloroquine (HCQ). Among the 245 respondents, discontinuation of the drug was linked to its ocular toxicity in approximately 7.3%. Most patients had taken HCQ for a period longer than five years, exceeding a dose of 5 mg/Kg. A lack of education and physician communication about medication toxicity was reported by approximately 40.8% of the participants. Despite the knowledge about HCQ retinopathy, the drug is prescribed to autoimmune disease patients at an inappropriate dosage. Knowledge obtained from physicians' communication may improve the health outcomes of chronically ill patients. Rheumatologists and ophthalmologists should work together to recognize patients at risk of hydroxychloroquine toxicity and ensure they receive proper education and adhere to periodic follow-up.

Choriocapillaris Flow Deficits Quantification in Hydroxychloroquine Retinopathy Using Swept-Source Optical Coherence Tomography Angiography

This study aims to quantitatively analyze choriocapillaris (CC) alterations using swept-source optical coherence tomography angiography (SS-OCTA) in eyes presenting with hydroxychloroquine (HCQ) toxic retinopathy and to compare it to patients under HCQ without toxic retinopathy and to healthy controls. For image analysis, CC en-face slabs were extracted from macular 6 × 6 mm SS-OCTA scans and a compensation method followed by the Phansalkar local thresholding was performed. Percentage of flow deficits (FD%) and other related biomarkers were computed for comparison. Fourteen eyes (7 patients) presenting with HCQ toxic retinopathy, sixty-two eyes (31 patients) under HCQ without signs of toxicity, and sixty eyes of 34 healthy controls were included. With regards to FD%, FD average size, and FD number there was a significant difference between the three groups (p < 0.05 with radius 4 and radius 8 pixels). Eyes presenting with HCQ toxicity had significantly higher FD% and average size, and a significantly lower number of FDs, with both radius 4 and 8 pixels. In conclusion, FD quantification demonstrates that CC involvement is present in HCQ toxic retinopathy, therefore giving pathophysiological insights with regards to the CC as being either the primary or secondary target of HCQ toxicity.

Hydroxychloroquine Causes Early Inner Retinal Toxicity and Affects Autophagosome-Lysosomal Pathway and Sphingolipid Metabolism in the Retina

Hydroxychloroquine (HCQ) is an anti-malarial drug but also widely used to treat autoimmune diseases like arthritis and lupus. Although there have been multiple reports of the adverse effect of prolonged HCQ usage on the outer retina, leading to bull's-eye maculopathy, the effect of HCQ toxicity on the inner retina as well as on overall visual functions has not been explored in detail. Furthermore, lack of an established animal model of HCQ toxicity hinders our understanding of the underlying molecular mechanisms. Here, using a small clinical study, we confirmed the effect of HCQ toxicity on the inner retina, in particular the reduction in central inner retinal thickness, and established a mouse model of chronic HCQ toxicity that recapitulates the effects observed in human retina. Using the mouse model, we demonstrated that chronic HCQ toxicity results in loss of inner retinal neurons and retinal ganglion cells (RGC) and compromises visual functions. We further established that HCQ treatment prevents autophagosome-lysosome fusion and alters the sphingolipid homeostasis in mouse retina. Our results affirm the notion that HCQ treatment causes early damage to the inner retina and affects visual functions before leading to characteristic toxicity in the macular region of the outer retina, 'bull's-eye maculopathy.' We also provide insights into the underlying molecular mechanisms of HCQ retinal toxicity that may involve autophagy-lysosomal defects and alterations in sphingolipid metabolism.

Plasma homocysteine and macular thickness in older adults-the Rugao Longevity and Aging Study

OBJECTIVES

To determine the association of plasma homocysteine levels with retinal layer thickness in a large community cohort of older adults.

METHODS

The Rugao Longevity and Ageing Study is an observational, prospective and community-based cohort study. A total of 989 older adults who underwent spectral-domain optical coherence tomography (SD-OCT) were included and analyzed. Foveal, macular retinal nerve fibre layer (mRNFL) and ganglion cell layer plus inner plexiform layer (GC-IPL) thicknesses were measured by SD-OCT. Plasma homocysteine levels were measured using chemiluminescence immunoassay. Linear regression analyses were performed to evaluate the relationship between plasma homocysteine and retinal layer thickness while controlling for confounding factors.

RESULTS

Of the 989 participants, 500 (50.56%) were men. The mean age was 78.26 (4.58) years, and the mean plasma homocysteine level was 16.38 (8.05) μmol/L. In multivariable analyses, each unit increase in plasma homocysteine was associated with an 8.84 × 10^-2 (95% CI: -16.54 × 10^-2 to -1.15 × 10^-2, p = 0.032) μm decrease in the average inner thickness of the GC-IPL after controlling for confounding factors. The association remained significant even in participants without major cardiovascular disease or diabetes (β = -10.33 × 10^-2, 95% CI: -18.49 × 10^-2 to -2.18 × 10^-2, p = 0.013). No significant associations of plasma homocysteine levels with macular thickness or mRNFL were found in primary and sensitivity analyses (p > 0.05).

CONCLUSIONS

Increased plasma homocysteine levels are associated with a thinner GC-IPL. Plasma homocysteine may be a risk factor for thinner retinas in older adults.

Impact of Structural Changes on Multifocal Electroretinography in Patients With Use of Hydroxychloroquine

Purpose

To investigate the relationship between retinal structure and macular function in eyes screened for hydroxychloroquine (HCQ) toxicity.

Methods

Participants referred for hydroxychloroquine retinopathy screening with spectral domain optical coherence tomography (SD-OCT) and multifocal electroretinogram (mfERG) testing were included in the analysis. Amplitude and implicit time of mfERG N1 and P1 responses were included in the analysis. Ring ratios were computed for amplitude values as the ratio of rings 1–3:5 (R1–3:R5). A control group of healthy participants was included for comparison of SD-OCT metrics.

Results

Sixty-three eyes screened for HCQ retinopathy and 30 control eyes were analyzed. The outer nuclear layer (ONL) was significantly thinner in HCQ patients in the foveal (P = 0.008), parafoveal (P < 0.0001), and perifoveal (P < 0.0001) regions. The HCQ cohort was further divided into two subgroups according to the presence of structural clinically detectable retinopathy (i.e., structural damage as detected by multimodal imaging). HCQ eyes without retinopathy had a thinner ONL thickness in the foveal (P = 0.032), parafoveal (P < 0.0001), and perifoveal (P < 0.0001) regions and a thinner inner nuclear layer (INL) in the parafoveal region (P = 0.045 versus controls). Structural changes in HCQ patients without retinopathy were significantly associated with macular function as R2:R5 ring ratio of mfERG P1 amplitude was associated with INL (P = 0.002) and ONL (P = 0.044) thicknesses, and R3:R5 ring ratio of P1 amplitude was associated with ONL thickness (P = 0.004).

Conclusions

Our results suggest that structural alterations secondary to HCQ toxicity may occur in the absence of clinically detectable retinopathy, and this may reflect in an impaired macular function.

Visual Impact of Early Hydroxychloroquine-Related Retinal Structural Changes in Patients with Systemic Lupus Erythematosus

PURPOSE

The aim of the study was to assess the early retinal structural changes due to hydroxychloroquine (HCQ) use and its impact on visual acuity (VA) of patients with systemic lupus erythematosus (SLE).

PATIENTS AND METHODS

The study was conducted as a case-control study that included 60 eyes of 30 SLE patients treated with HCQ compared with 50 eyes of 25 healthy individuals. Patients were kept on 200 or 400 mg as daily maintenance dose. SLE patients were subgrouped into patients with normal VA and patients with decreased VA. All participants were assessed by the optical coherence tomography (OCT), and early structural abnormalities were recorded. The main outcomes and measures were best-corrected VA, drug exposure time, central macular thickness (CMT), inner segment-outer segment (IS-OS) junction disruption, ganglion cell complex † (GCC†, ganglion cell layer + inner plexiform layer), ganglion cell complex †† (GCC††, nerve fiber layer + GCC†), and peripapillary retinal nerve fiber layer. The characteristics of HCQ retinal toxicity were correlated to VA.

RESULTS

All OCT parameters were found to be significantly lower (p < 0.001) in HCQ patients with decreased VA than in controls. Patients receiving a daily dose of 400 mg had lower (p < 0.05) parameters than those receiving 200 mg. Patients with IS-OS disruption had lower CMT, GCC †, and GCC †† than those without (p < 0.05). VA was significantly correlated (p < 0.05) with CMT and drug exposure time.

CONCLUSIONS

The HCQ use caused OCT changes that precede clinically visible retinopathy and might be associated with slight VA reduction. Screening with OCT of patients receiving HCQ is essential to detect early vision loss.

Longitudinal Retinal Changes Induced by Hydroxychloroquine in Eyes without Retinal Toxicity

INTRODUCTION

This study aimed to evaluate the longitudinal changes in retinal layer thickness in patients treated with hydroxychloroquine without retinal toxicity.

METHODS

This is a longitudinal retrospective study of patients taking hydroxychloroquine followed in a hydroxychloroquine retinal toxicity screening program of a tertiary hospital between January 2010 and April 2019. Patients who performed 2 optical coherence tomography (OCT) scans at least 1 year apart were included. All subjects with hydroxychloroquine suspected or confirmed retinal toxicity, glaucoma, retinal pathology, or poor segmented images were excluded. Spectral-domain optical coherence tomography (Spectralis HRA-OCT, Heidelberg) was used to evaluate the macular area. Automatically segmented ETDRS retinal thickness maps were compared between the first and the last OCT evaluation available. Full retina (FR), inner retina (IRL), ganglion cells (GCL), inner nuclear (INL), and outer retina (ORL) layer thicknesses were measured in the foveolar, paracentral, and peripheral area.

RESULTS

The population included 144 eyes of 144 patients. The mean interval between OCT scans was 38.1 ± 18.4 months, and the mean cumulative dose was 406.9 ± 223.9 g. Foveolar (p = 0.040, p = 0.006, and p = 0.001, respectively) and paracentral (p = 0.006, p = 0.001, and p = 0.005, respectively) FR, IRL, and GCL decreased overtime. No differences were found in INL or ORL. A very weak correlation was found between age and foveal IRL change overtime (p = 0.037; R = 0.175), as well as between the hydroxychloroquine time of use and foveal GCL variation (p = 0.032; R = 0.179).

CONCLUSION

Hydroxychloroquine was found to cause progressive thinning of the inner retinal layers, specifically in the GCL of the foveolar and paracentral areas, but no changes were observed in the outer retina.

[Differential diagnosis of hydroxychloroquine-induced retinal damage]

Coronavirus infection is currently en extremely relevant scientific topic due to the emergence of a new serotype that causes a condition identified as Severe Acute Respiratory Syndrome (SARS)-COV-2. Chloroquine and hydroxychloroquine have a long history of use against other infectious diseases, they are available and inexpensive, so the possibility of using them in vivo and in vitro to suppress the infectious agent was examined. Despite the noted therapeutic potential of these drugs, it was necessary to take into account the toxicological aspects that dictate the importance of rational use of 4-aminoquinoline derivatives. This review analyzes literature on the development patterns of hydroxychloroquine retinopathy, basic principles of diagnosis and differentiation of this condition from other types of retinal pathology.

Choroidal Thickness and microRNA146 in Lupus Nephritis Patients

Purpose

To evaluate the choroidal thickness (CT) in the macular area in patients with lupus nephritis and to compare the results with both non-nephritic patients and normal control. To assess the relation of CT to serum microRNA146, disease duration, activity index, and medications.

Patients and Methods

Thirty-five SLE patients and thirty normal healthy controls were enrolled for this cross-sectional prospective study. All participants have undergone optical coherence tomography using RTVue OCT (Optovue Inc., Fremont, CA, USA). The scan used was the macular cross 6-mm line. We measured CT from the posterior edge of the retinal pigment epithelium (RPE) to the choroid-sclera junction at subfovea, and 750 µm both temporal and nasal to the fovea.

Results

The mean central subfoveal CT in patients was 275.7 ± 41.0 µm (214-374 µm), and the mean central subfoveal CT in the control group was 364.5± 23.0 µm (323-411µm). There was a significant thinning at all three points in patients compared to the control group (p<0.001, Mann-Whitney U-test). In the patients group, subfoveal choroid in non-nephritic subgroup showed significant thinning compared to nephritic subgroup (p=0.032, Mann-Whitney U-test). Drusen-like deposits (DLDs) were detected in 22.9% (8/35) of patients and none in control (p=.023). MiRNA146 showed a significant positive correlation with nephritic lupus patients (r=0.036, P=0.04).

Conclusion

The choroidal thickness was significantly thicker among the nephritic lupus patients as compared to the non-nephritic subgroup. Both SLE patients' subgroups are thinner than normal control. Subfoveal choroidal thickening can be considered a biomarker in nephritic lupus especially in conjunction with an increase in miRNA146a. All SLE patients are at risk of small Drusen-like deposits.

Genetic susceptibility to hydroxychloroquine retinal toxicity

Background: Hydroxychloroquine retinal toxicity can occur in up to 7.5% of patients receiving treatment; however, possible genetic risk factors are poorly understood. The main objective of the study was to explore candidate genetic risk factors for retinal toxicity.Materials and Methods: Case-control study of patients with confirmed hydroxychloroquine retinal toxicity identified through ophthalmology departments of tertiary care hospitals and private ophthalmic practice in Australia. Participants were 26 Caucasian patients with hydroxychloroquine retinal toxicity who were matched with control subjects for age, gender, treatment duration and indication for hydroxychloroquine treatment. Participants underwent clinical examination, optical coherence tomographic scanning, automated field testing and whole exome sequencing of DNA extracted from saliva or blood. Outcome measures were grade of hydroxychloroquine toxicity and mutations in a panel of 40 candidate genes.Results: No susceptibility or protective factors were identified in either the cohort as a whole or any subset of patients.Conclusions and relevance: Further larger studies, with whole-exome analysis and consideration of additional modifying genes are needed.

Comparison of Fundus-Guided Microperimetry and Multifocal Electroretinography for Evaluating Hydroxychloroquine Maculopathy

Purpose

To compare retinal function by using fundus-guided microperimetry (MP) and multifocal electroretinography (mfERG) for detecting hydroxychloroquine (HCQ) maculopathy.

Methods

Forty-six eyes of 25 patients referred to our clinical practice for HCQ maculopathy assessment and 3 groups of normal control subjects were evaluated by mfERG and MP. Macular structure was assessed using spectral-domain optical coherence tomography (SD-OCT). Ring ratios from the three innermost mERG rings were compared with average sensitivity of each MP ring at approximately equivalent distances from the fovea. HCQ toxicity was defined as an mfERG ring ratio or mean MP ring sensitivity >2 standard deviations below the normal mean. The sensitivity and specificity of MP to detect HCQ toxicity relative to mfERG were evaluated.

Results

MP rings MR2 and MR3 were positively correlated with corresponding mfERG ring ratios (r = 0.52, P = 0.002 and r = 0.56, P < 0.001 respectively). Ring 2 and ring 3 measures of MP and mfERG were significantly worse in HCQ eyes than controls (P < 0.001). The sensitivity of MP to detect toxicity for MR1 through MR3 ranged from 33% to 88%, whereas specificity ranged from 72% to 85%. Through rings 1 to 3, the frequency of abnormal function ranged from 20% to 48% for MP, 11% to 35% for mfERG, and 41% to 45% for SD-OCT.

Conclusions

The frequency of detection of HCQ toxicity with MP was greater than with mfERG. MP showed an overall good sensitivity and moderate specificity in detecting HCQ-induced functional deficits.

Translational Relevance

Results from this study may allow clinicians to improve screening accuracy for HCQ toxicity by using the alternative modality of MP.

Hydroxychloroquine retinopathy - implications of research advances for rheumatology care

Despite advances in therapy for rheumatic diseases, hydroxychloroquine remains almost universally recommended for the treatment of systemic lupus erythematosus (SLE), and is often used in the management of other rheumatic diseases such as rheumatoid arthritis (RA). However, the major dose-limiting toxicity of hydroxychloroquine is retinopathy that can lead to loss of vision. New highly sensitive screening methods can identify early stages of retinopathy, and studies that include these modalities have indicated a substantially higher prevalence of hydroxychloroquine retinopathy than was previously recognized, resulting in revisions to ophthalmology guidelines and the recommendation of a low dose of hydroxychloroquine for many patients. However, the efficacy of low-dose hydroxychloroquine for treating SLE and other rheumatic diseases is unknown. Further studies are required to establish the effectiveness and retinal safety of the latest hydroxychloroquine treatment recommendations.

Role of optical coherence tomography in the early detection of macular thinning in rheumatoid arthritis patients with chloroquine retinopathy

Background:

Chloroquine and hydroxychloroquine are drugs that are primarily used for the treatment of malaria and are also recommended for treating connective tissue disorders, autoimmune diseases, and some dermatological and inflammatory diseases. Treatment with these drugs has potential risk for the development of retinopathy, clinically characterized by bilateral pigment changes in the macula, as one serious ocular complication. The aim of this research was to evaluate the parafoveal and perifoveal macular retinal thickness, as central foveal thickness in adult patients with rheumatoid arthritis (RA) on chloroquine therapy using optical coherence tomography (OCT).

Materials and Methods:

In this cross-sectional study, 56 RA patients (56 eyes) were included and examined. All patients were treated with chloroquine (tablets resochin or delagil) at a dose of 250 mg/day without treatment with steroids and other immunosuppressive drugs. Patients were divided into two groups, namely, Group I patients - no visible changes in the macula (26 patients) and Group II patients- with visible changes in the macula (30 patients). The central fovea thickness and parafoveal and perifoveal retinal thickness in all quadrants were measured by OCT and compared in both groups.

Results:

There are a significantly higher number of eyes without thinning of the macula in Group I patients than in Group II (P < 0.001) patients. There are a higher number of patients with recorded parafoveal thinning in Group II patients, especially in the inferior, nasal, and temporal sectors, respectively (P < 0.05).

Conclusion:

Maculopathy is the main side effect of chloroquine therapy in RA patients that can be detected by OCT in the early stages of the macular involvement.

Evaluation of photoreceptor outer segment length in hydroxychloroquine users

OBJECTIVE

This study aims to evaluate the photoreceptor outer segment (PROS) length in patients who use hydroxychloroquine (HCQ) prior to the development of retinopathy.

METHODS

In this prospective, single-centre, comparative study, 44 patients using HCQ for ≥5 years, 30 patients using HCQ <5 years, and 45 age- and sex-matched healthy controls were enrolled. The participants underwent a detailed ophthalmologic examination, spectral-domain optical coherence tomography (SD-OCT) imaging, and 10-2 automated visual field testing. The PROS length was defined as the distance between the inner surface of the ellipsoid zone and the inner surface of the retina pigment epithelium. The measurements were performed subfoveally and at 500-1000-1500 µm temporally and nasally to the foveola.

RESULTS

The mean PROS length of long-term users (≥5 years) was statistically greater than the controls at all measurement points (p < 0.001 at all points). Although the subfoveal PROS length was comparable between the long-term and short-term users (p = 0.148), the parafoveal PROS length measurements (nasal 1500 µm, nasal 1000 µm, nasal 500 µm, temporal 1000 µm, and temporal 1500 µm) of the long-term users were significantly greater than those of the short-term users (p < 0.001, p = 0.002, p = 0.027, p = 0.018, p = 0.001, respectively). No significant difference was found between the short-term users and the controls (p = 0.815, p = 0.395, p = 0.093, p = 0.079, p = 0.133, p = 0.686, p = 0.341, respectively).

CONCLUSION

The PROS length was greater in patients who used HCQ ≥5 years. Possible retinal pigment epithelium toxicity may have caused this finding.

A New Objective Parameter in Hydroxychloroquine-Induced Retinal Toxicity Screening Test: Macular Retinal Ganglion Cell-Inner Plexiform Layer Thickness

Objectives

This study aims to detect hydroxychloroquine (HCQ)-induced retinal toxicity at an earlier stage through the use of spectral-domain optical coherence tomography device, especially by measuring macular retinal ganglion cell-inner plexiform layer (RGC-IPL) thickness.

Patients and methods

In this study, 92 eyes of 46 Caucasian female patients (mean age 53.6±8.1 years; range 32 to 69 years) who were taking HCQ were assigned to group 1, while 80 eyes of 40 age-matched Caucasian female control subjects (mean age 56.1±10.7 years; range 34 to 71 years) were assigned to group 2. RGC-IPL thickness and retinal nerve fiber layer thickness were measured in all subjects by Cirrus high-definition optical coherence tomography model 5000 device using macular cube 512¥128 and optic disc cube 200¥200 protocols. We performed an evaluation to see if there was any difference between the measured values of the groups. The correlation between average RGC-IPL thickness measures and cumulative dose of HCQ and duration of use was analyzed.

Results

Retinal ganglion cell-inner plexiform layer of group 1 was found to be statistically thinner than that of group 2 both on average and in all segments (superior, superonasal, inferonasal, inferotemporal and superotemporal) except inferior segment when segmented (p<0.05). Additionally, a statistically significant negative correlation was found between the average RGC-IPL thickness and cumulative dose of HCQ (r= -0.371, p=0.001) as well as the duration of use (r= -0.308, p=0.006).

Conclusion

Patients taking HCQ were found to have decreased RGC-IPL thickness at an early stage due to retinal toxicity induced by the drug. We think that measuring the RGC-IPL thickness may become an important objective in HCQ screening tests.

Macular ganglion cell-inner plexiform layer thickness for detection of early retinal toxicity of hydroxychloroquine

PURPOSE

This study evaluated the macular ganglion cell-inner plexiform layer (GC-IPL) thickness using spectral-domain (SD) optical coherence tomography (OCT) in patients with chronic exposure to hydroxychloroquine (HCQ).

METHODS

A total of 90 patients (90 eyes) treated with HCQ for at least 5 years and normal controls were included in the study. A fundus examination, automated threshold perimetry, and GC-IPL thickness measurements using the Cirrus high-definition OCT ganglion cell analysis algorithm were performed in all patients treated with HCQ. Average, minimum, and sectorial macular GC-IPL thicknesses were compared between the patients and controls.

RESULTS

There was no statistically significant difference in age or sex between the groups. The anterior segment and fundoscopy were normal in all patients and controls. Visual field (VF) testing was normal in all patients. The average, minimum, and sectorial macular GC-IPL thicknesses were significantly lower in patients than those in control subjects.

CONCLUSIONS

There was significant thinning of the macular GC-IPL in the absence of clinically evident HCQ-related retinopathy and VF abnormalities. Measurements of the macular GC-IPL thickness using SD-OCT may therefore be useful in the early diagnosis and in monitoring the progression of retinal changes in patients receiving long-term HCQ therapy.

Antimalarial drugs and the prevalence of mental and neurological manifestations: A systematic review and meta-analysis

Background: Antimalarial drugs affect the central nervous system, but it is difficult to differentiate the effect of these drugs from that of the malaria illness. We conducted a systematic review to determine the association between anti-malarial drugs and mental and neurological impairment in humans.  Methods: We systematically searched online databases, including Medline/PubMed, PsychoInfo, and Embase, for articles published up to 14th July 2016. Pooled prevalence, heterogeneity and factors associated with prevalence of mental and neurological manifestations were determined using meta-analytic techniques.  Results: Of the 2,349 records identified in the initial search, 51 human studies met the eligibility criteria. The median pooled prevalence range of mental and neurological manifestations associated with antimalarial drugs ranged from 0.7% (dapsone) to 48.3% (minocycline) across all studies, while it ranged from 0.6% (pyrimethamine) to 42.7% (amodiaquine) during treatment of acute malaria, and 0.7% (primaquine/dapsone) to 55.0% (sulfadoxine) during prophylaxis. Pooled prevalence of mental and neurological manifestations across all studies was associated with an increased number of antimalarial drugs (prevalence ratio= 5.51 (95%CI, 1.05-29.04); P=0.045) in a meta-regression analysis. Headaches (15%) and dizziness (14%) were the most common mental and neurological manifestations across all studies. Of individual antimalarial drugs still on the market, mental and neurological manifestations were most common with the use of sulphadoxine (55%) for prophylaxis studies and amodiaquine (42.7%) for acute malaria studies. Mefloquine affected more domains of mental and neurological manifestations than any other antimalarial drug.  Conclusions: Antimalarial drugs, particularly those used for prophylaxis, may be associated with mental and neurological manifestations, and the number of antimalarial drugs taken determines the association. Mental and neurological manifestations should be assessed following the use of antimalarial drugs.

Antimalarial drugs and the prevalence of mental and neurological manifestations: A systematic review and meta-analysis

Background: Antimalarial drugs affect the central nervous system, but it is difficult to differentiate the effect of these drugs from that of the malaria illness. We conducted a systematic review to determine the association between anti-malarial drugs and mental and neurological impairment in humans.  Methods: We systematically searched online databases, including Medline/PubMed, PsychoInfo, and Embase, for articles published up to 14th July 2016. Pooled prevalence, heterogeneity and factors associated with prevalence of mental and neurological manifestations were determined using meta-analytic techniques.  Results: Of the 2,349 records identified in the initial search, 51 human studies met the eligibility criteria. The median pooled prevalence range of mental and neurological manifestations associated with antimalarial drugs ranged from 0.7% (dapsone) to 48.3% (minocycline) across all studies, while it ranged from 0.6% (pyrimethamine) to 42.7% (amodiaquine) during treatment of acute malaria, and 0.7% (primaquine/dapsone) to 55.0% (sulfadoxine) during prophylaxis. Pooled prevalence of mental and neurological manifestations across all studies was associated with an increased number of antimalarial drugs (prevalence ratio= 5.51 (95%CI, 1.05-29.04); P=0.045) in a meta-regression analysis. Headaches (15%) and dizziness (14%) were the most common mental and neurological manifestations across all studies. Of individual antimalarial drugs still on the market, mental and neurological manifestations were most common with the use of sulphadoxine (55%) for prophylaxis studies and amodiaquine (42.7%) for acute malaria studies. Mefloquine affected more domains of mental and neurological manifestations than any other antimalarial drug.  Conclusions: Antimalarial drugs, particularly those used for prophylaxis, may be associated with mental and neurological manifestations, and the number of antimalarial drugs taken determines the association. Mental and neurological manifestations should be assessed following the use of antimalarial drugs.

VOLUMETRIC SINGLE-LAYER INNER RETINAL ANALYSIS IN PATIENTS WITH HYDROXYCHLOROQUINE TOXICITY

PURPOSE

To compare retinal layer volumes using spectral-domain optical coherence tomography between eyes with hydroxychloroquine (HCQ) toxicity and control eyes.

METHODS

Using a previously validated algorithm, volumetric analysis from the macular cube scan of the ganglion cell layer, inner plexiform layer, inner nuclear layer, and outer retina (outer plexiform layer to retinal pigment epithelium) layers were compared in three sets of patients: patients with a clinical diagnosis of HCQ toxicity, age-matched patients taking HCQ but not manifesting overt toxicity, and age-matched control patients.

RESULTS

There were 14 patients in each group. The ganglion cell layer (P = 0.01), inner plexiform layer (P = 0.004), inner nuclear layer (P < 0.001), and outer plexiform layer to retinal pigment epithelium (P < 0.001) volumes were significantly reduced in HCQ toxicity eyes relative to the HCQ exposure eyes. There were no significant inner and outer retinal volume differences between the HCQ exposure group and group with no HCQ use (P > 0.05 for all layers). Increasing disease severity correlated with increasing volume loss in the inner retina (2.27 mm in early disease vs. 1.78 mm in advanced retinopathy, P = 0.02).

CONCLUSION

Hydroxychloroquine toxicity seems to result in both outer and inner retinal volumetric thinning compared with age-matched control patients and patients taking HCQ but not manifesting toxicity.

Hydroxychloroquine retinopathy: A review of imaging

Hydroxychloroquine (HCQ) retinopathy can result in permanent vision loss. In early stages of HCQ retinopathy, patients are usually asymptomatic with preservation of visual acuity. We aspire that our review, in conjunction with the American Academy of Ophthalmology screening guidelines, shall shed light on effective screening measures utilizing multimodal imaging techniques to detect early signs of HCQ retinopathy before advanced changes manifest clinically.

The measurement repeatability using different partition methods of intraretinal tomographic thickness maps in healthy human subjects

Purpose

To determine the repeatability and profiles with different partition methods in intraretinal thickness layers in healthy human subjects, using optical coherence tomography (OCT).

Methods

A custom-built ultrahigh-resolution OCT was used to acquire three-dimensional volume of the macula in 20 healthy subjects. The dataset was acquired twice using the macular cube 512×128 protocol in an area of 6×6 mm² centered on the fovea. Commercially available segmentation software (Orion™) was used to segment the dataset into thickness maps of six intraretinal layers. The coefficient of repeatability and intraclass coefficient of correlation (ICC) were analyzed using hemispheric zoning and sectors defined by the Early Treatment Diabetic Retinopathy Study (ETDRS).

Results

All datasets were successfully segmented to create six thickness maps of individual intraretinal layers. Coefficients of repeatabilities of these layers in hemispheric zones ranged from 0.9 to 6.6 µm, with an average of 3.6 µm (standard deviation [SD] 1.4), which was not significantly different compared to ETDRS sectors (P>0.05). ICCs of these layers in hemispheric zones ranged from 0.68 to 0.99, with an average of 0.91 (SD 0.07). There were no significant differences in ICCs between two zoning methods (P>0.05). Significant variations of tomographic intraretinal thicknesses were found between the inner and outer annuli and among the quadrantal sectors within the inner and outer annuli (P<0.05). Significant variations of the quadrantal sectors including both inner and outer annuli were evident in intraretinal layers (P<0.05) except for the outer plexiform layer.

Conclusion

The measurement repeatabilities of tomographic thicknesses of intraretinal layers are comparable using both hemispheric and ETDRS partitions in volumetric data combined with the commercially available segmentation software. In keeping with known, normal anatomical variation, significant differences in tomographic thickness in various intraretinal layers were apparent in both hemispheric and ETDRS sectors.

FUNDUS AUTOFLUORESCENCE FINDINGS IN EARLY CHLOROQUINE MACULOPATHY

BACKGROUND/PURPOSE

Toxic maculopathy is a rare but severe complication of chloroquine intake. Although the phenotype of established maculopathy was analyzed in detail, few data exist on the ophthalmologic findings in the early stage.

METHODS

The authors present 4 female patients with unequivocal signs of chloroquine maculopathy (bilateral [peri-]central scotoma in the visual fields, structural alterations of the macula in the optical coherence tomography) but normal or atypical findings as to fundus autofluorescence imaging.

RESULTS

In all patients, optical coherence tomography showed perifoveal thinning and subtle alterations of the outer retinal layers. In one patient, the latter was limited to the pericentral region, whereas it showed a more diffuse distribution in two other patients. One patient showed a combination of pericentral and diffuse damage. Multifocal electroretinography was recorded in three patients and revealed the typical (peri-)central amplitude reductions.

CONCLUSION

A normal fundus autofluorescence does not rule out toxic maculopathy. Optical coherence tomography and multifocal electroretinography seem to be more sensitive in the early stage of the disease. In case of typical complaints and visual fields, the optical coherence tomography has to be evaluated for subtle alterations of the outer retina. Their presence justifies the cessation of the drug. Multifocal electroretinography may be of special value in these problematic cases.

Effect of Hydroxychloroquine on the Retinal Layers: A Quantitative Evaluation with Spectral-Domain Optical Coherence Tomography

Purpose. To evaluate the effect of hydroxychloroquine on retinal pigment epithelium- (RPE-) Bruch's membrane complex, photoreceptor outer segment, and macular ganglion cell-inner plexiform layer (GCIPL) thicknesses using spectral-domain optical coherence tomography (SD-OCT). Methods. In this prospective case-control study, 51 eyes of 51 hydroxychloroquine patients and 30 eyes of 30 healthy subjects were included. High-quality images were obtained using a Cirrus HD-OCT with 5-line raster mode; the photoreceptor inner segment (IS) and outer segment (OS), sum of the segments (IS + OS), and RPE-Bruch's membrane complex were analyzed. Results. The thicknesses of the IS + OS and OS layers were significantly lower in the hydroxychloroquine subjects compared to the control subjects (P < 0.05). RPE-Bruch's membrane complex thicknesses were significantly higher in the hydroxychloroquine subjects than for those of the control subjects (P < 0.05). The minimum and temporal-inferior macular GCIPL thicknesses were significantly different between the patients with hydroxychloroquine use and the control subjects (P = 0.04 and P = 0.03, resp.). Conclusions. The foveal photoreceptor OS thinning, loss of GCIPL, and RPE-Bruch's membrane thickening were detected in patients with hydroxychloroquine therapy. This quantitative approach using SD-OCT images may have important implications to use as an early indicator of retinal toxicity without any visible signs of hydroxychloroquine retinopathy.

Expanded spectral domain-OCT findings in the early detection of hydroxychloroquine retinopathy and changes following drug cessation

Purpose

To report expanded SD-OCT findings of HCQ retinopathy that may assist the clinician in earlier diagnosis. To characterize structural changes of HCQ retinopathy with SD-OCT after drug cessation.

Methods

Setting: Private practice and academic institution. Patient Population: Patients at New England Eye Center and Ophthalmic Consultants of Boston in Boston, MA diagnosed with HCQ retinopathy and followed after drug cessation. Retrospective clinical data review by the Boston Image Reading Center. Main Outcome Measures: SD-OCT findings suggestive of HCQ retinopathy before parafoveal ellipsoid disruption. Change in SD-OCT morphological appearance and retinal thickness of each of the nine subfields corresponding to the Early Treatment of Diabetic Retinopathy Study areas.

Results

Thirty eyes with HCQ retinopathy were followed with SD-OCT after drug cessation. Findings before disruption of the parafoveal EZ included parafoveal outer nuclear layer (ONL) thinning, disruption of the parafoveal interdigitation zone, and reduced reflectivity of the parafoveal EZ. In early toxicity, 75 % developed progression after drug cessation, including disruption of the parafoveal EZ and retinal pigment epithelium and thinning of the ONL. Eyes with obvious toxicity had greater inferior outer ring thinning 12 months after drug cessation compared to early toxicity (p = 0.002, 95 % CI −2 to −8 μm). In obvious toxicity, the nasal inner subfield showed more thinning than the temporal inner subfield at 12 months after drug cessation (p = 0.018, 95 % CI −1 to −8 μm).

Conclusions

Once HCQ retinopathy is diagnosed and the medication is discontinued, structural retinal changes commonly occur.

Retinal Toxicity in Patients Treated With Hydroxychloroquine: A Cross-Sectional Study

Hydroxychloroquine (HCQ) is an antimalarial medication that can also be used to treat autoimmune diseases. However, it can produce irreversible changes to the retina that lead to visual impairment. The aim of this study was to determine the proportion of patients treated with HCQ who develop retinal toxicity and the risk factors for the development of HCQ-induced retinal toxicity among Iranian patients. The is a cross-sectional clinical study of 59 patients who were treated with HCQ during 2014-2015. A questionnaire was used to collect data on the following demographic and clinical factors: age, gender, type of rheumatic disease, history of cataract surgery, daily and cumulative HCQ dose, and duration of HCQ use. Retinal toxicity was diagnosed on the basis of the automated perimetry results of the central 10° of vision and spectral domain optical coherence tomography. The associations between the demographic and clinical factors and retinal toxicity were assessed, and P < 0.05 was considered statistically significant. Retinal toxicity was detected in 18 (30.5%) of the patients, and 5 (8.5 %) developed color vision impairments. There was no association between retinal toxicity and sex (P = 0.514), history of cataract surgery (P = 0.479), type of rheumatic disease (P = 0.539), or daily HCQ dose (P = 0.062). However, there was a significant positive association between retinal toxicity and age (P = 0.006), cumulative HCQ dose (P = 0.002), and duration of HCQ use (P < 0.001). In conclusion, the risk factors for retinal toxicity after HCQ treatment were advanced age, use of a higher cumulative HCQ dose, and a longer duration of treatment.

Hydroxychloroquine-related retinal toxicity

HCQ is widely used for the treatment of rheumatic diseases, particularly lupus and RA. It is generally well tolerated, but retinopathy is a concern. Retinopathy is rare, but is sight threatening, generally irreversible and may progress even after cessation of therapy. Damage may be subclinical. Although a number of risk factors have been proposed (such as duration of therapy and cumulative dose), the many exceptions (e.g. retinopathy on low-dose HCQ, or no retinopathy after a very large cumulative dose of HCQ) highlight our limited understanding of the disease process. Novel technologies such as optical coherence tomography (OCT), fundus autofluorescence (FAF) and multifocal electroretinogram (mfERG) may provide the earliest structural and functional evidence of toxicity in these stages. Along with the well-established technique of central visual field testing (10-2 visual fields), these modalities are increasingly being used as part of screening programmes. The ideal single test with high sensitivity and high specificity for HCQ retinopathy has still not been achieved. Screening for HCQ retinopathy remains an area of considerable debate, including issues of when, who and how to screen. Commonly accepted risk factors include receiving >6.5 mg/kg/day or a cumulative dose of >1000 g of HCQ, being on treatment for >5 years, having renal or liver dysfunction, having pre-existing retinopathy and being elderly. HCQ continues to be a valuable drug in treating rheumatic disease, but clinicians need to be aware of the associated risks and to have arrangements in place that would enable early detection of toxicity.

Localization of damage in progressive hydroxychloroquine retinopathy on and off the drug: inner versus outer retina, parafovea versus peripheral fovea

PURPOSE

To evaluate the relative involvement of inner and outer retina in hydroxychloroquine (HCQ) retinopathy while on the drug, and after drug cessation, using data from spectral-domain optical coherence tomography (SD-OCT).

METHODS

A total of 102 SD-OCT scans were obtained from 11 patients (classified as having early, moderate, or severe stages of toxicity) over a period of 4 years after cessation of HCQ. The inner and outer retina boundaries were identified automatically to measure thickness and characterize progression topographically.

RESULTS

The segmentation of retinal layers was verified in SD-OCT cross-sections for all eyes and scans included in this study (a total of 102 scans). Topographic analysis showed that inner retina was not involved in HCQ toxicity to any meaningful degree, either between stages of retinopathy or after the drug is stopped. The characteristic bull's eye pattern of outer macula thinning appears when comparing moderate retinopathy (before any RPE damage) to the early stage. Later damage, as toxicity evolved to a severe stage, was diffuse across most of the macula. If the drug was stopped at an early or moderate stage, progression was limited to the first year and occurred diffusely without parafoveal localization.

CONCLUSIONS

Hydroxychloroquine retinopathy primarily involves outer retina (photoreceptors). Outer retinal thinning while using HCQ initially involves the parafovea, but becomes diffuse across the macula as damage progresses or after drug cessation. When HCQ is stopped at an early or moderate stage (before RPE damage), progression seems to be limited to the first year.

Spectral-Domain Optical Coherence Tomography of Preclinical Chloroquine Maculopathy in Egyptian Rheumatoid Arthritis Patients

Purpose. To evaluate the role of spectral-domain optical coherence tomography (SD-OCT) in early detection of Chloroquine maculopathy in rheumatoid arthritis (RA) patients. Methods. 40 left eyes of 40 female rheumatoid arthritis patients who received treatment chloroquine for more than one year were recruited in the study. All patients had no symptoms or signs of Chloroquine retinopathy. They were evaluated using SD-OCT, where the Central Foveal Thickness (CFT), parafoveal thickness and perifoveal thickness, average Retinal Nerve Fiber Layer (RNFL) thickness, and Ganglion Cell Complex (GCC) measurements were measured and compared to 40 left eyes of 40 normal females. Results. The mean CFT was found to be thinner in the Chloroquine group (238.15 µm ± 22.49) than the normal controls (248.2 µm ± 19.04), which was statistically significant (p value = 0.034). The mean parafoveal thickness was lesser in the Chloroquine group than the control group in all quadrants (p value <0.05). The perifoveal thickness in both groups showed no statistically significant difference (p value >0.05) in all quadrants. No significant difference was detected between the two groups regarding RNFL, GCC, or IS/OS junction. Conclusions. Preclinical Chloroquine toxicity can lead to early thinning in the central fovea as well as the parafoveal regions that is detected by SD-OCT.

Spectral domain optical coherence tomography for early detection of retinal alterations in patients using hydroxychloroquine

Objective:

To determine whether early toxic effects from hydroxychloroquine (HCQ) could be detected by spectral-domain optical coherence tomography (SD-OCT) before symtomatic visual loss occured.

Materials and Methods:

Fifteen subjects with a history of the chronic use of hydroxychloroquine monotherapy for less than five years without fundus changes (group 1) and 15 visually normal healthy subjects (group 2) were enrolled in this study. All participants underwent systemic and ocular examination, visual field testing, and macular scan imaging using SD-OCT.

Results:

There were no significant differences in sex and ages between the groups (P > 0.05). Mean duration of HCQ usage in group 1 was 2.5 ± 1.34 (range:1-5) years. Visual field testing with central 10-2 threshold program was normal in all subjects. Inner retinal thickness in parafoveal and perifoveal area were found to be significantly lower in group 1 compared to group 2 (P < 0.01 for perifoveal, P < 0.05 for parafoveal retinal measurements). However, significant thinning was demonstrated only in full retinal thickness of perifoveal area in group 1 compared to group 2 (P: 0.013). Parafoveal and perifoveal inner retinal thickness measurements of inferior quadrants were significantly reduced in group 1 compared to group 2 (P < 0.01).

Conclusion:

Significant thinning of inner retinal layer especially in parafoveal and perifoveal areas in the absence of clinical fundus changes was observed in our study. We consider that SD-OCT may determine when inner retinal thinning starts in these patients and may contribute a quantitative approach to the early diagnosis and progression of retinal changes.

Spectral domain optical coherence tomography as an effective screening test for hydroxychloroquine retinopathy (the "flying saucer" sign)

Purpose

While the long-term incidence of hydroxychloroquine (HCQ) retinopathy is low, there remains no definitive clinical screening test to recognize HCQ toxicity before ophthalmoscopic fundus changes or visual symptoms. Patients receiving HCQ were evaluated with spectral domain optical coherence tomography (SD OCT) to assess the feasibility of identifying HCQ retinopathy at an early stage.

Methods

Twenty-five patients referred for the evaluation of hydroxychloroquine toxicity underwent a comprehensive ocular examination, Humphrey visual field (HVF) perimetry, time domain OCT, and SD OCT. Some patients with screening abnormalities also underwent further diagnostic testing at the discretion of the treating providers.

Results

Five patients were found to have SD OCT findings corresponding to HCQ toxicity and retinal damage as seen by clinical exam and/or HVF perimetry. Two patients with advanced toxicity were found to have significant outer retina disruption in the macula on SD OCT. Three patients with early HCQ toxicity and HVF 10-2 perifoveal defects were found to have loss of the perifoveal photoreceptor inner segment/outer segment (IS/OS) junction with intact outer retina directly under the fovea, creating the “flying saucer” sign. While two of these three patients had early ophthalmoscopic fundus changes, one had none.

Conclusion

Outer retinal abnormalities including perifoveal photoreceptor IS/OS junction disruption can be identified by SD OCT in early HCQ toxicity, sometimes even before ophthalmoscopic fundus changes are apparent. SD OCT may have a potential complementary role in screening for HCQ retinopathy due to its quick acquisition and because it is more objective than automated perimetry.