Detection of early hydroxychloroquine retinal toxicity enhanced by ring ratio analysis of multifocal electroretinography

Accelerated hydroxychloroquine toxic retinopathy

PURPOSE

To report a case series of patients with retinal toxicity due to hydroxychloroquine (HCQ) within a short span of treatment.

METHODS

A retrospective review of case records of patients with accelerated HCQ toxicity within 1 year of starting the treatment was done. Systemic co-morbidities, details of HCQ treatment, details of ocular examination, and results of multimodal investigations were noted.

RESULTS

Nine patients (1 male, 8 females) with age ranging from 40 to 73 years (mean 54.2 ± 13.4 years) who showed accelerated HCQ toxicity were included. None had systemic conditions or drug history predisposing to early HCQ toxicity. The treatment duration ranged from 2 to 11 months and the cumulative HCQ dose ranged from 18 to 120 g (mean 45.0 ± 33.0 g). The visual acuity was normal in 8 (88.9%) patients and retinal evaluation was normal in 4 (44.4%). Optical coherence tomography was abnormal in 4 (44.4%). Six (66.6%) cases had reduced sensitivity in the parafoveal point on visual field testing. All 9 cases had multifocal electroretinographic changes diagnostic of HCQ toxicity. The HCQ treatment was stopped in 8 and continued with reduced dose in 1 patient. The mean duration of follow-up was 11.2 ± 9.6 months during which 5 patients showed improved mfERG and 1 patient had a stable mfERG. Visual fields improvement was noted in 2 cases.

CONCLUSIONS

Patients on HCQ need to be kept on regular monitoring with more frequent follow-ups to detect signs of early onset toxicity and prevent permanent visual impairment. mfERG is an important diagnostic tool for HCQ toxicity.

Evaluation of early retinal changes in patients on long-term hydroxychloroquine using optical coherence tomography angiography

Background

Connective tissue diseases (CTD), including systemic lupus erythematosus and rheumatoid arthritis (RA), have long been treated with hydroxychloroquine (HCQ). However, prolonged HCQ use poses a risk of adverse effects, particularly retinopathy.

Objective

To detect early retinal changes assessed by optical coherence tomography angiography (OCTA) in CTD patients with long-term HCQ treatment and to explore the relationship between OCTA parameters and the concentrations of HCQ and its metabolites.

Design

A cross-sectional study conducted from March 2020 to October 2021 at the First Affiliated Hospital of Anhui Medical University.

Methods

The area and perimeter of the foveal avascular zone (FAZ), the thickness of the fovea and parafovea, and the vascular density of the superficial capillary plexus (SCP) and deep capillary plexus (DCP) in each area of the macula were measured by OCTA in 43 CTD patients treated with HCQ for over 6 months. Meantime, blood concentrations of HCQ and its metabolites were determined by high-performance liquid chromatography-tandem mass spectrometry, and the clinical documents of all 43 involved patients were collected.

Results

There is no significant correlation between OCTA outcomes and the patient's age, disease duration, and weight-dependent dose. HCQ cumulative duration positively correlated with FAZ area and perimeter (r = 0.419, p = 0.005 and r = 0.407, p = 0.007, respectively) and negatively correlated with the foveal vessel density in DCP (r = -0.378, p = 0.012). HCQ cumulative dose had a positive correlation with FAZ area and perimeter (r = 0.445, p = 0.003 and r = 0.434, p = 0.004, respectively) and had a negative correlation with foveal vessel density in SCP and DCP (r = -0.383, p = 0.011 and r = -0.424, p = 0.005, respectively). OCTA outcomes did not correlate with HCQ and its metabolite concentrations.

Conclusion

OCTA could be used to detect microvascular changes in the macula of CTD patients with long-term HCQ therapy. It was not found the concentrations of HCQ and its metabolites were associated with retinal vascular changes.

Quantitative analysis of optical coherence tomography imaging in patients with different severities of hydroxychloroquine toxicity

PURPOSE

To determine the diagnostic validity of quantitative measures derived from optical coherence tomography (OCT) images in their ability to discriminate between cohorts of eyes unaffected by hydroxychloroquine (HCQ) and those with a range of toxicity severities, including mild toxicity.

METHODS

Prospective, single-centre, case-control study conducted between August 2010 and May 2017. Participants were exposed to HCQ for at least 5 years (mean±SD =14±7.2 years) and classified into affected and unaffected cohorts based on the American Academy of Ophthalmology's 2016 recommendations. For affected eyes, severity (groups 1-4) was assigned based on the extent of ellipsoid zone loss. For all eyes, spectral domain-OCT scans were analysed quantitatively to compute inner retinal thickness (IRT), outer retinal thickness (ORT), and minimum signal intensity (MI) and compared across toxicity groups.

RESULTS

Of the 85 participants (mean age 59±12 years, 93% female), 30 had retinal toxicity. Significant differences in ORT and MI were observed between each affected severity group and unaffected eyes. Significant differences in IRT were observed for groups 3-4 but not groups 1-2. ORT and MI were each able to discriminate between unaffected and group 1 eyes with the highest discrimination at the inner subfields (areas under the curve, AUC=0.96 for ORT and AUC=0.93 for MI).

CONCLUSIONS

Quantitative analysis of OCT scans revealed significant differences between eyes with and without toxicity in two different measures. Each individual metric could discriminate between the unaffected and the lowest severity category, suggesting their potential utility in screening for HCQ toxicity in patients at risk.

Hydroxychloroquine-induced Retinal Toxicity

Long-term use of hydroxychloroquine can cause retinopathy, which may result in severe and progressive visual loss. In the past decade, hydroxychloroquine use has markedly increased and modern retinal imaging techniques have enabled the detection of early, pre-symptomatic disease. As a consequence, the prevalence of retinal toxicity in long-term hydroxychloroquine users is known to be higher than was previously estimated. The pathophysiology of the retinopathy is incompletely characterised, although significant advances have been made in understanding the disease from clinical imaging studies. Hydroxychloroquine retinopathy elicits sufficient public health concern to justify the implementation of retinopathy screening programs for patients at risk. Here, we describe the historical background of hydroxychloroquine retinopathy and summarize its current understanding. We review the utility and limitations of each of the mainstream diagnostic tests used to detect hydroxychloroquine retinopathy. The key considerations towards a consensus on the definition of hydroxychloroquine retinopathy are outlined in the context of what is known of the natural history of the disease. We compare the current screening recommendations for hydroxychloroquine retinopathy, identifying where additional evidence is required, and the management of proven cases of toxicity. Finally, we highlight the areas for further investigation, which may further reduce the risk of visual loss in hydroxychloroquine users.

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.

MERCI: a machine learning approach to identifying hydroxychloroquine retinopathy using mfERG

PURPOSE

Hydroxychloroquine (HCQ) is an anti-inflammatory drug in widespread use for the treatment of systemic auto-immune diseases. Vision loss caused by retinal toxicity is a significant risk associated with long term HCQ therapy. Identifying patients at risk of developing retinal toxicity can help prevent vision loss and improve the quality of life for patients. This paper presents updated reference thresholds and examines the diagnostic accuracy of a machine learning approach for identifying retinal toxicity using the multifocal Electroretinogram (mfERG).

METHODS

A retrospective study of patients referred for mfERG testing to detect HCQ retinopathy. A consecutive series of all patients referred to Kensington Vision and Research Centre between August 2017 and July 2020 were considered eligible. Eyes suspect for other ocular pathology including widespread retinal disease and advanced macular pathology unrelated to HCQ or with poor quality mfERG recordings were excluded. All patients received mfERG testing and Ocular Coherence Tomography (OCT) imaging. Presence of HCQ retinopathy was based on ring ratio analysis using clinical reference thresholds established at KVRC coupled with structural features observed on OCT, the clinical reference standard. A Support Vector Machine (SVM) using selected features of the mfERG was trained. Accuracy, sensitivity and specificity are reported.

RESULTS

1463 eyes of 748 patients were included in the study. SVM model performance was assessed on 293 eyes from 265 patients. 55 eyes from 54 patients were identified as demonstrating HCQ retinopathy based on the clinical reference standard, 50 eyes from 49 patients were identified by the SVM. Our SVM achieves an accuracy of 85.3% with a sensitivity of 90.9% and specificity of 84.0%.

CONCLUSIONS

Machine learning approaches can be applied to mfERG analysis to identify patients at risk of retinopathy caused by HCQ therapy.

Evaluation of Corneal and Retinal Toxicity in Rheumatoid Arthritis Patients Treated with Hydroxychloroquine

INTRODUCTION

The study aimed to assess the ocular toxicity of hydroxychloroquine (HCQ) by confocal microscopy, multifocal electroretinography (mfERG), and scanning laser polarimetry with variable corneal compensation (GDxVCC) in patients with rheumatoid arthritis (RA).

METHODS

A cross-sectional, comparative case series study was retrospectively conducted on 61 patients under HCQ treatment for RA without fundoscopic anomalies (group 1), 65 RA patients with no HCQ treatment (group 2), and 27 normal subjects (group 3). A comprehensive ophthalmological examination, including confocal microscopy, mfERG, and GDxVCC, was performed in the three groups.

RESULTS

In group 1, the duration of treatment ranged from 19 to 96 months (54.9 ± 15.2 months). The mean cumulative dose of HCQ was 446.1 ± 164.0 g (range 114-864 g). Confocal microscopy revealed hyper-reflective abnormal particles in 45 patients (73.8%) and beaded, tortuous fibers in 34 patients (55.7%) in group 1. No corneal change was observed in the other two groups. The mfERG responses in the 6 concentric rings (R1-R6) among the three groups differed except at R3 (all p < 0.05), and data from R1-R6 were not significantly different between groups 2 and 3. The retinal nerve fiber layer thicknesses were statistically thinner in group 1 than in groups 2 and 3 (all p < 0.05).

CONCLUSIONS

Early signs of corneal and neural retina structure changes were detected in patients with RA treated with HCQ. Whether these findings should be a mark of drug recession still needs further study and more evidence.

Visual Field Sensitivity Prediction Using Optical Coherence Tomography Analysis in Hydroxychloroquine Toxicity

Purpose

This study investigates the association between local retina structure and visual function in a cohort with long-term hydroxychloroquine (HCQ) use.

Methods

The study included 84 participants (54 participants without toxicity and 30 participants with toxicity) with history of chronic HCQ use (14.5 ± 7.4 years) who had testing with spectral-domain optical coherence tomography (SD-OCT) imaging and Humphrey 10-2 visual fields. Optical coherence tomography (OCT) metrics (total and outer retina thickness [TRT and ORT], minimum intensity [MinI], and ellipsoid zone [EZ] loss) were sampled in regions corresponding to visual field test locations. Univariate linear correlations were investigated and a multivariate random forest regression using a combination of OCT metrics was used to predict visual field sensitivity by locus using a leave-one-out cross-validation strategy.

Results

In univariate linear regression, EZ loss demonstrated the strongest relationship with visual field sensitivities in the parafoveal ring with R2 = 0.58. TRT and ORT revealed positive correlations with visual field sensitivity (R2 = 0.57 and 0.40, respectively), whereas total and outer retinal MinI yielded negative correlations (R2 = 0.10 and 0.22). The multivariate model improved correlations (R2 = 0.66) yielding a root mean squared error of 3.8 decibel (dB). Feature importance analysis identified EZ loss as the most relevant predictor of function.

Conclusions

Multiple OCT-derived quantitative metrics used in combination can provide information to predict local sensitivities. The results indicate a strong relationship between retinal function and OCT measures, which contribute to the understanding of the retinal toxicity caused by HCQ as well as being applicable to outcome development for other degenerative diseases of the outer retina.

A novel 5-ring multifocal electroretinography stimulus for detecting hydroxychloroquine retinal toxicity

Purpose

Multifocal electroretinogram (mfERG) shows great utility as a screening tool to detect early hydroxychloroquine (HCQ) retinopathy, but its widespread use is limited by the lack of accessibility and long test duration. In this study, we evaluated a novel concentric 5-ring mfERG stimulus to provide a simplified and rapid protocol for screening HCQ toxicity.

Methods

Patients referred for HCQ retinopathy screening were consented to this observational cross-sectional study. Patients with amblyopia, high refractive error (more than 8 diopters), other retinal diseases precluding appropriate evaluation or history of retinal surgery were excluded. The data were collected from patients undergoing HCQ screening at a single center from July 2019 to March 2020. Patients were tested with the new concentric 5-ring mfERG stimulus, standard 61-hexagon mfERG stimulus, spectral domain optical coherence tomography and automated 10-2 visual fields. For the main outcome, the 5-ring mfERG was compared to 61-hexagon stimulus to determine the time-to-test completion and assess the association between ring (R1–R5) amplitude and ring ratio compared against cumulative dose, dose by real body weight and duration of therapy using Pearson correlation.

Results

In total, 52 patients (104 eyes; 5 males and 47 females) were recruited with a mean age of 59 years (range 23–85 years). The 5-ring protocol was markedly quicker to perform (1.3 ± 0.2 min; mean (SD)) compared to the 61-hexagon protocol (5.2 ± 0.6 min), p < 0.0001; n = 10 patients. The new R2/R5 ring ratio showed a moderate correlation with daily dose (r = − 0.640), cumulative dose (r = − 0.581) and duration of therapy (r = − 0.417). Similar correlations were observed with the new R2/R4 ring ratio which were not significantly different from the new R2/R5 correlation coefficients. The new R2/R5 ring ratio demonstrated a stronger correlation with daily (p = 0.002) and cumulative dose (p = 0.0001) compared to the 61-hexagon stimulus.

Conclusions

In this exploratory study, our novel 5-ring mfERG protocol significantly shortened data acquisition time while providing comparable results to the standard 61-hexagon stimulus for detecting HCQ-induced electrophysiological changes that are correlated with HCQ dosages and treatment duration. Our protocol has the potential to be more clinically practical by simplifying routine screening.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10633-021-09858-4.

Effect of spatial averaging on the amplitude ring ratio in multifocal electroretinography

PURPOSE

The purpose of this study was to evaluate the effect of spatial averaging on the multifocal electroretinography (mfERG) amplitude ring ratios used in screening for hydroxychloroquine (HCQ) toxicity.

METHODS

This was a retrospective review of the records of patients screened for HCQ retinopathy at the USF Eye Institute (University of South Florida) during the period of 2015-2020. Patients were tested binocularly with Diagnosys mfERG system (Diagnosys LLC, Lowell, MA). Only the records of patients referred internally were used. The effects of the lowest level (level 1, or 8%) of spatial averaging on the P1 amplitude ring ratios used for screening of HCQ maculopathy: R1/R2, R2/R5, R5/R3 and R5/R4, were evaluated.

RESULTS

The records of 40 patients (4 males, 36 females) aged 54.4 ± 14.1 years were selected for analysis. The use of spatial averaging had a significant effect on P1 amplitudes, and on the ring ratios and this effect was correlated with the magnitude of the amplitudes and the ratios. Spatial averaging diminished P1 amplitude significantly in ring 1 (p < 0.0001) and increased it slightly in ring 4 (p < 0.05), while it had no effect on the amplitude of the other three rings. Although as a group spatial averaging had a moderate effect on the R1/R2 ratio (~ -15%), on an individual basis the range was wide, from -36 to 43%. The effect on the other ring ratios was similar: The average group effect was ~ -5%, ~ -3.4% and ~ -4% for R2/R5, R5/R3 and R5/R4 ratios, but individual effects ranged from 0.18% to -27.3%, 0.9% to -14.2% and 0.9% to -26.2%, respectively.

CONCLUSIONS

For all ring ratios used in this analysis, spatial averaging has a substantial effect on the ring ratio, which could affect the interpretation of the results. Therefore, use of spatial averaging should be avoided when analyzing mfERG results for HCQ screening.

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 electrophysiology in the assessment of toxicity and deficiency states affecting the visual system

Visual disturbance or visual failure due to toxicity of an ingested substance or a severe nutritional deficiency can present significant challenges for diagnosis and management, for instance, where an adverse reaction to a prescribed medicine is suspected. Objective assessment of visual function is important, particularly where structural changes in the retina or optic nerve have not yet occurred, as there may be a window of opportunity to mitigate or reverse visual loss. This paper reviews a number of clinical presentations where visual electrophysiological assessment has an important role in early diagnosis or management alongside clinical assessment and ocular imaging modalities. We highlight the importance of vitamin A deficiency as an easily detected marker for severe combined micronutrient deficiency.

Evaluation of optical coherence tomography angiography parameters in patients treated with Hydroxychloroquine

Background

One of the major side effects of Hydroxychloroquine (HCQ) is retinopathy. The aim of this study was to evaluate the Optical coherence tomography angiography (OCTA) parameters in a group of patients who have Hydroxychloroquine-induced retinopathy based on Multifocal electroretinography (mfERG) with a group who do not have retinopathy.

Method

This is a Cross-Sectional Study. In this study, patients with Rheumatoid arthritis (RA) or Systemic lupus erythematosus (SLE) who had been taking Hydroxychloroquine for at least 7 years were included. MfERG and OCTA imaging were performed for all patients. Patients were divided into Normal mfERG and Abnormal mfERG groups based on mfERG results. OCTA parameters were studied in these two groups.

Result

Sixty-one patients (61 eyes) were included. Forty-one patients had SLE and 20 patients had RA. Forty patients (66.7%) had Abnormal mfERG. The mean vascular density (VD) in Superficial capillary plexus (SCP) layer was not significantly different between Normal mfERG and Abnormal mfERG groups (P-Value> 0.05). Mean VD in SCP layer was not significantly different between Normal mfERG and Abnormal mfERG groups (P-Value> 0.05). In RA subgroup, mean VD in SCP layer in PeriFovea region in Abnormal mfERG group was significantly lower than normal group (P-Value < 0.05). Mean VD in deep capillary plexus (DCP) layer in Whole Image, Superior Hemi, Inferior Hemi, PeriFovea area in Abnormal mfERG group was significantly lower than normal group (P-Value < 0.05). This discrepancy was also observed in the RA subgroup but not in the SLE subgroup. The mean of none of the parameters of foveal avascular zone (FAZ) (mm2), Flow Area of Outer Retina (mm2) and Flow Area of Choriocapillaris (mm2) were not statistically significant between the groups Abnormal mfERG and Normal mfERG. (p-value> 0.05).

Conclusion

VD in the DCP layer decreased in abnormal mfERG patients compared to patients with normal mfERG. But it seems that VD in SCP layer, FAZ Area and Flow Area are similar in both groups. OCTA may be used as a non-invasive tool in the diagnosis of early stages of HCQ-induced retinopathy, especially in RA patients, but further studies are needed.

Quantitative Fundus Autofluorescence in HCQ Retinopathy

Purpose

To increase our understanding of the mechanisms underlying hydroxychloroquine (HCQ) retinopathy, analyses by quantitative fundus autofluorescence (qAF) and near-infrared fundus autofluorescence (NIR-AF) were compared to results obtained by recommended screening tests.

Methods

Thirty-one patients (28 females, 3 males) were evaluated with standard automated perimetry and spectral domain optical coherence tomography (SD-OCT); 28 also had multifocal electroretinography (mfERG). Measurement of short-wavelength fundus autofluorescence (SW-AF) by qAF involved the use of an internal fluorescent reference and intensity measurements in eight concentric segments at 7° to 9° eccentricity. For semiquantitative analysis of NIR-AF, intensities were acquired along a vertical axis through the fovea.

Results

Four of 15 high-dose (total dose >1000 g, daily dose >5.0 mg/kg) patients and one of 16 low-dose (total dose <1000 g, daily dose 4.4 mg/kg) patients were diagnosed with HCQ-associated retinopathy based on abnormal 10-2 visual fields, SD-OCT, and SW-AF imaging. Three of the high-dose patients also had abnormal mfERG results. Of the five patients exhibiting retinopathy, two had qAF color-coded images revealing higher intensities inferior, nasal, and lateral to the fovea. The abnormal visual fields also exhibited superior-inferior differences. Mean NIR-AF gray-level intensities were increased in four high-dose patients with no evidence of retinopathy. In two patients with retinopathy, NIR-AF intensity within the parafovea was below the normal range. One high-dose patient (6.25 mg/kg) had only abnormal mfERG results.

Conclusions

These findings indicate that screening for HCQ retinopathy should take into consideration superior-inferior differences in susceptibility to HCQ retinopathy.

LONGITUDINAL CHANGES IN EYES WITH HYDROXYCHLOROQUINE RETINAL TOXICITY

PURPOSE

To characterize functional and structural changes in hydroxychloroquine (HCQ) retinal toxicity after drug cessation.

METHODS

Twenty-two patients (91% female; mean age 58.7 ± 11.4 years; mean duration of HCQ treatment 161.1 ± 90 months; mean dose 5.9 ± 1.9 mg/kg) with detected HCQ retinopathy were monitored for 6 months to 82 months after HCQ cessation with multimodal imaging including spectral domain optical coherence tomography and fundus autofluorescence imaging at 488 nm (standard) and 787 nm (near-infrared autofluorescence). Tests of visual function including visual acuity, Humphrey visual field testing, and multifocal electroretinography (mfERG) were performed. Study eyes were categorized into four separate severity stages by qualitative grading of spectral domain optical coherence tomography macular scans taken at the time of HCQ cessation. Changes in outcome measures between drug cessation and last follow-up visit were computed and compared between eyes of different severity stages.

RESULTS

Study eyes (n = 44) were categorized based on optical coherence tomography criteria into: Stage 1 (subtle changes confined to parafoveal region; n = 14), Stage 2 (clear localized changes in parafovea; n = 17), Stage 3 (extensive parafoveal changes; n = 7), and Stage 4 (foveal involvement, n = 6). Visual acuity measurements across follow-up were stable in Stage 1 and Stage 2 eyes but decreased significantly in Stage 3 and 4 eyes. Humphrey visual field measures were also stable in stages 1 and 2 but deteriorated in Stage 3 eyes. mfERG testing demonstrated significant improvement in the R1/R2 ratio after HCQ cessation in Stage 1 eyes (mean change = -0.86 ± 0.79, P = 0.03) but did not change significantly in eyes of higher stages. Decreases in macular thickness in ≥1 of 9 Early Treatment Diabetic Retinopathy Study subfields on spectral domain optical coherence tomography were found in eyes of all stages, with Stage 2 eyes demonstrating thinning in most subfields (eight of nine subfields). In eyes with a measurable central foveal ellipsoid zone band island (9 of 17 Stage 2 eyes and 7 of 7 Stage 3 eyes), progressive decrease in the foveal ellipsoid zone band length was observed in 6 of 9 (67%) Stage 2 eyes and 6 of 7 (86%) Stage 3 eyes. Changes indicative of progressing retinopathy were detected in 17% of Stage 1 eyes, 46% of Stage 2 eyes, and 43% of Stage 3 eyes on standard fundus autofluorescence imaging, and in 17% of Stage 1 eyes, 38% of Stage 2 eyes, and 14% of Stage 3 eyes on near-infrared autofluorescence imaging.

CONCLUSION

Eyes with detected HCQ retinopathy do not demonstrate general stability in retinal structure and function after HCQ cessation but instead demonstrate a range of changes during follow-up whose magnitudes correlate with retinopathy severity at the time of cessation. After cessation, eyes with only subtle and localized retinopathy were mostly stable and may show some functional improvement, whereas more severely affected eyes continued to progress. These findings provide evidence that early detection and prompt cessation in HCQ retinopathy may be needed to arrest retinopathy progression and to optimize long-term outcomes.

MICROPERIMETRY AS A SCREENING TEST FOR HYDROXYCHLOROQUINE RETINOPATHY: The Hard-Risk-1 Study

PURPOSE

To assess the sensitivity and specificity of microperimetry as a screening test to detecting hydroxychloroquine retinopathy.

METHODS

Retrospective cohort study. Patients with history of hydroxychloroquine use for more than 5 years and with concomitant microperimetry and multifocal electroretinogram testing were retrospectively reviewed. Microperimetry was considered positive if there were three or more contiguous scotoma points in the parafoveal region. Multifocal electroretinogram was used as gold standard and was considered positive if there was an increased R1/R2 ring ratio (>2.5) or reduced R1 absolute amplitude (<9.0). Sensitivity, specificity, positive predictive value, and negative predictive value of microperimetry were calculated.

RESULTS

A total of 197 patients were reviewed. Hydroxychloroquine retinopathy was present in 22 (11%) patients. Their mean (SD) age was 54 (14) years, and 96% were women. Their mean (SD) daily dose was 5.7 (1.3) mg/kg, cumulative dose was 2041 (1,548) g, and duration of use was 15 (10) years. Sensitivity, specificity, positive predictive value, and negative predictive value of microperimetry were 73%, 93%, 53%, and 96%, respectively.

CONCLUSION

Microperimetry has inferior sensitivity but good specificity in detecting hydroxychloroquine retinopathy (compared with multifocal electroretinogram). As such, it may be a useful ancillary test to exclude retinopathy, especially in high-risk patients or those with conflicting results on different modalities.

Electrophysiological and SD-OCT findings in patients receiving chloroquine therapy in relation to cumulative dosage and duration of treatment

PURPOSE

Assessment of multifocal ERG (mfERG) changes in patients treated with chloroquine and their correlation with morphological abnormalities, detected by spectral-domain optical coherence tomography in relation to cumulative dosage.

METHODS

Data from 37 eyes of 20 patients were retrospectively collected, and one randomly selected eye per patient was considered for statistical analysis. Eyes were divided into three groups according to mfERG and visual acuity findings: normal, early and advanced maculopathy. Functional measures of the first three mfERG rings were compared with retinal thickness measures of the corresponding OCT ETDRS circles. Data on cumulative dose and duration of therapy were also evaluated.

RESULTS

The mean mfERG values progressively decreased according to the stage of the disease. In particular in the early maculopathy group, amplitudes were significantly reduced in all the three central rings. The mean ring ratio R1/R2 was abnormal only in the early maculopathy group. OCT thickness measures were significantly lower in all the three ETDRS circles in the advanced maculopathy group, and in the paracentral circle in the early maculopathy group. Considering all the eyes, there was a statistically significant correlation between functional and morphological values (p < 0.001). High chloroquine cumulative dosages were always associated with retinal toxic effects, whereas lower cumulative dosages generated different levels of toxicity.

CONCLUSIONS

This study shows a strong association between mfERG ring values and the corresponding OCT thickness measures; however, mfERG may enhance early detection of functional changes in patients treated with chloroquine, especially in ambiguous cases. At low chloroquine cumulative dosages, different subjects might have different susceptibilities to the drug.

The Diagnostic Utility of Multifocal Electroretinography in Detecting Chloroquine and Hydroxychloroquine Retinal Toxicity

PURPOSE

To evaluate multifocal electroretinography (mfERG) as a screening test for detecting hydroxychloroquine and chloroquine toxicity.

DESIGN

Diagnostic accuracy study.

METHODS

Patients referred to the University of Ottawa for hydroxychloroquine or chloroquine retinopathy screening during 2011-2014 underwent 10-2 automated visual field, spectral domain optical coherence tomography, and mfERG testing. Patients with amblyopia, high myopia or hyperopia, coexisting retinal disease, or prior surgery were excluded. Abnormalities in parafoveal ring amplitudes or ring ratios were considered a positive mfERG result. We used the definition for hydroxychloroquine and chloroquine toxicity provided by the 2016 American Academy of Ophthalmology recommendations. Area under the curve (AUC) for each mfERG parameter and the sensitivity and specificity of mfERG were calculated. Logistic regression was used to model the effect of covariates in receiver operating characteristic (ROC) analyses.

RESULTS

In total, 63 patients (47 female, 16 male) were included. Of 120 eyes, 16 (13.3%) had toxicity according to the American Academy of Ophthalmology guidelines, and 39 (32.5%) had positive mfERG findings. mfERG was found to have a sensitivity of 1.00 (95% CI 0.79-1.00) and a specificity of 0.78 (95% CI 0.69-0.85). Ring 2 amplitude had the best performance among all parameters (AUC 0.97, 95% CI 0.94-1.00). Ring 2 amplitude decreased linearly with increasing cumulative dose and daily dose.

CONCLUSIONS

The high sensitivity of parafoveal depression on mfERG and its relationship to cumulative and daily dose illustrates an important role for objective functional testing. The high false-positive rate suggests a potential period where physiologic dysfunction is detected objectively on mfERG before structural change on spectral domain optical coherence tomography.

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.

Early hydroxychloroquine retinopathy: optical coherence tomography abnormalities preceding Humphrey visual field defects

Background/Aims

Hydroxychloroquine (HCQ) retinopathy may result in severe and irreversible vision loss, emphasising the importance of screening and early detection. The purpose of this study is to report the novel finding of early optical coherence tomography (OCT) abnormalities due to HCQ toxicity that may develop in the setting of normal Humphrey visual field (HVF) testing.

Methods

Data from patients with chronic HCQ exposure was obtained from seven tertiary care retina centres. Ten patients with HCQ-associated OCT abnormalities and normal HVF testing were identified. Detailed analysis of the OCT findings and ancillary tests including colour fundus photography, fundus autofluorescence, multifocal electroretinography and microperimetry was performed in these patients.

Results

Seventeen eyes from 10 patients illustrated abnormalities with OCT and normal HVF testing. These OCT alterations included (1) attenuation of the parafoveal ellipsoid zone and (2) loss of a clear continuous interdigitation zone. Several eyes progressed to advanced parafoveal outer retinal disruption and/or paracentral visual field defects.

Conclusion

Patients with high risk HCQ exposure and normal HVF testing may develop subtle but characteristic OCT abnormalities. This novel finding indicates that, in some cases of early HCQ toxicity, structural alterations may precede functional impairment. It is therefore important to employ a screening approach that includes OCT to assess for these early findings. Ancillary testing should be considered in cases with suspicious OCT changes and normal HVFs.

Influence of standard corneal cross-linking in keratoconus patients on macular profile

Purpose

To determine the effect of corneal cross-linking (CXL) on retinal structure and function.

Methods

The current study was conducted on 42 eyes of 21 patients with keratoconus (KCN) who were candidates for CXL due to disease progression. The Optovue optical coherence tomography (OCT) (Optovue Inc., Fremont, USA) from macula and multifocal electroretinography (mERG) were performed on all patients prior to surgery and at 1- and 6- month follow-up. Structural and functional parameters of macula including retinal thickness in OCT, and amplitude and latency of electroretinogram were compared between eyes that underwent surgery and control fellow eyes during the study period.

Results

A statistically significant increase in central foveal, foveal, parafoveal, and perifoveal thickness was observed at 1-month follow-up. The changes were non-significant at 6 months. Although a statistically significant reduction in amplitude and increase in latency in both rings 2 and 3 were observed at 1 month in mERG, only amplitude changes in ring 2 remained significant at 6 months.

Conclusion

Transient anatomical and functional alterations following CXL were observed in the current study.

Optical Coherence Tomography Minimum Intensity as an Objective Measure for the Detection of Hydroxychloroquine Toxicity

Purpose

As optical coherence tomography (OCT) minimum intensity (MI) analysis provides a quantitative assessment of changes in the outer nuclear layer (ONL), we evaluated the ability of OCT-MI analysis to detect hydroxychloroquine toxicity.

Methods

Fifty-seven predominantly female participants (91.2% female; mean age, 55.7 ± 10.4 years; mean time on hydroxychloroquine, 15.0 ± 7.5 years) were enrolled in a case-control study and categorized into affected (i.e., with toxicity, n = 19) and unaffected (n = 38) groups using objective multifocal electroretinographic (mfERG) criteria. Spectral-domain OCT scans of the macula were analyzed and OCT-MI values quantitated for each subfield of the Early Treatment Diabetic Retinopathy Study (ETDRS) grid. A two-sample U-test and a cross-validation approach were used to assess the sensitivity and specificity of toxicity detection according to OCT-MI criteria.

Results

The medians of the OCT-MI values in all nine of the ETDRS subfields were significantly elevated in the affected group relative to the unaffected group (P < 0.005 for all comparisons), with the largest difference found for the inner inferior subfield (P < 0.0001). The receiver operating characteristic analysis of median MI values of the inner inferior subfields showed high sensitivity and high specificity in the detection of toxicity with area under the curve = 0.99.

Conclusions

Retinal changes secondary to hydroxychloroquine toxicity result in increased OCT reflectivity in the ONL that can be detected and quantitated using OCT-MI analysis. Analysis of OCT-MI values demonstrates high sensitivity and specificity for detecting the presence of hydroxychloroquine toxicity in this cohort and may contribute additionally to current screening practices.

Facilitating the analysis of the multifocal electroretinogram using the free software environment R

Purpose:

The large amount of data rendered by the multifocal electroretinogram (mfERG) can be analyzed and visualized in various ways. The evaluation and comparison of more than one examination is time-consuming and prone to create errors. Using the free software environment R we developed a solution to average the data of multiple examinations and to allow a comparison of different patient groups.

Methods:

Data of single mfERG recordings as exported in .csv format from a RETIport 21 system (version 7/03, Roland Consult) or manually compiled .csv files are the basis for the calculations. The R software extracts response densities and implicit times of N1 and P1 for the sum response, each ring eccentricity, and each single hexagon. Averages can be calculated for as many subjects as needed. The mentioned parameters can then be compared to another group of patients or healthy subjects. Application of the software is illustrated by comparing 11 patients with chloroquine maculopathy to a control group of 7 healthy subjects.

Results:

The software scripts display response density and implicit time 3D plots of each examination as well as of the group averages. Differences of the group averages are presented as 3D and grayscale 2D plots. Both groups are compared using the t-test with Bonferroni correction. The group comparison is furthermore illustrated by the average waveforms and by boxplots of each eccentricity.

Conclusions:

This software solution on the basis of the programming language R facilitates the clinical and scientific use of the mfERG and aids in interpretation and analysis.

ELECTRORETINOGRAPHIC AND VISUAL-EVOKED POTENTIAL CHANGES IN RELATION TO CHELATION MODALITY IN CHILDREN WITH THALASSEMIA

PURPOSE

To evaluate possible benefits of using electrophysiological investigations for detecting retinal and visual pathway changes and correlating them with chelation modality in children with thalassemia.

METHODS

This study included 60 patients on single oral iron chelator (deferasirox) (Group 1), 60 on deferoxamine chelator (Group 2), and 60 controls (Group 3). Participants underwent full ophthalmologic examination, pattern visual-evoked potential, pattern electroretinogram, and multifocal electroretinogram.

RESULTS

Fundus showed no abnormalities. Multifocal electroretinogram mean P1 amplitude showed statistically significant differences in all 5 rings, amplitudes being significantly lower in Groups 1 and 2 than Group 3; moreover, significantly lower in Group 2 than Group 1. There was a statistically significant difference between groups regarding P50 wave latency and N35-P50 of pattern electroretinogram amplitude (P < 0.001 and P < 0.001, respectively). However, there were no statistically significant differences between groups regarding N95 wave of pattern electroretinogram and pattern visual-evoked potential waves' amplitude and latency. Multiple regression analyses illustrated that chelator was the most important determinant for multifocal electroretinogram and P50 parameters.

CONCLUSION

Preclinical electrophysiologic changes existed in thalassemics, more obvious in those on deferoxamine. Electrophysiologic studies analysis denotes an early toxic macular insult rather than optic nerve affection. Thus, regular follow-up using multifocal electroretinogram and pattern electroretinogram is recommended.

Risk of Retinal Toxicity in Longterm Users of Hydroxychloroquine

Objective.

Several studies have reported risk factors for hydroxychloroquine (HCQ) retinal toxicity, but data are limited for patients of Asian ancestry. The aim of this study was to investigate the rate of and factors for HCQ retinal toxicity in the Korean population.

Methods.

There were 123 patients enrolled in this study who were using or had used HCQ. Retinal toxicity was detected using spectral domain optical coherence tomography, fundus autofluorescence, multifocal electroretinography, and automated visual field testing. Binary logistic regression analysis was performed to identify factors associated with HCQ retinal toxicity.

Results.

Mean duration of HCQ use and mean HCQ dose in study participants was 10.1 years and 6.4 mg/kg, respectively. We found 17 patients (13.8%) with HCQ retinal toxicity among 123 patients. Patients with retinal toxicity took HCQ ranging from 6.7–21.9 years and daily dosage ranging from 4.9–9.1 mg/kg. Only 1 patient had retinal toxicity among patients with daily dose < 5.0 mg/kg. These factors increased the risk of HCQ retinal toxicity: longer duration of HCQ use [adjusted OR (aOR) = 4.71, 95% CI 2.18–10.15 for duration of HCQ use in 5-yr increments], higher daily HCQ dose (aOR = 3.34, 95% CI 1.03–10.80 for daily HCQ dose in 100-mg increments), and the presence of kidney disease (aOR = 8.56, 95% CI 1.15–64.00).

Conclusion.

HCQ retinal toxicity is associated with duration of HCQ use, daily HCQ dose, and presence of kidney disease. Proper dosing of maximum 5 mg/kg and regular screening according to risk factors are important in HCQ use.

Retinal toxicity related to hydroxychloroquine in patients with systemic lupus erythematosus and rheumatoid arthritis

PURPOSE

To compare the retinal toxicity due to hydroxychloroquine (HCQ) use in patients with systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) using multifocal electroretinography (mfERG), fundus autofluorescence (FAF) and optical coherence tomography (OCT).

METHODS

Patients who were using HCQ due to SLE and RA, and healthy subjects evaluated in this study. Central foveal thickness (CFT), inner-outer segment (IS-OS) junction irregularity, retinal nerve fiber layer thickness, mfERG and FAF measurements were performed to evaluate retinal toxicity.

RESULTS

Study included 35 eyes of 35 SLE patients, 40 eyes of 40 RA patients and 20 eyes of 20 healthy subjects. In SLE group, retinal abnormality was found in three eyes with mfERG, in one eye with FAF and in four eyes with OCT. In RA group, retinal abnormality was found in 10 eyes with mfERG, in five eyes with FAF and in nine eyes with OCT. A statistically significant difference was found with respect to mfERG between "eyes with abnormal responses and without abnormal responses" and "eyes with abnormal responses and controls" (p < 0.05). A statistically significant difference was found with respect to CFT between "eyes with IS-OS junction irregularities and without IS-OS junction irregularities" and "eyes with/without IS-OS junction irregularities and controls" (p < 0.05).

CONCLUSIONS

The use of HCQ seems to cause retinal toxicity more often in RA patients compared to SLE patients. For the early detection of retinal changes, OCT and mfERG can be used as screening tools due to their higher sensitivity rates compared to other tests.

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.

A Critical Review of the Effects of Hydroxychloroquine and Chloroquine on the Eye

Hydroxychloroquine (HCQ) and chloroquine have been used for more than 50 years to treat systemic lupus erythematosus (SLE) and other rheumatic diseases. In general, these drugs are well tolerated and rarely need to be discontinued because of an adverse systemic reaction. However, both medications can be irreversibly toxic to the retina. A new study indicates that toxicity is not as rare as once believed, but depends critically on daily dosage and duration of use, as well as other risk factors. With attention to dosage and other factors, and with proper screening for early signs of toxicity, HCQ can be prescribed with relative safety even over long periods of time.

Recommendations on Screening for Chloroquine and Hydroxychloroquine Retinopathy (2016 Revision)

BACKGROUND

The American Academy of Ophthalmology recommendations on screening for chloroquine (CQ) and hydroxychloroquine (HCQ) retinopathy are revised in light of new information about the prevalence of toxicity, risk factors, fundus distribution, and effectiveness of screening tools.

PATTERN OF RETINOPATHY

Although the locus of toxic damage is parafoveal in many eyes, Asian patients often show an extramacular pattern of damage. DOSE: We recommend a maximum daily HCQ use of ≤5.0 mg/kg real weight, which correlates better with risk than ideal weight. There are no similar demographic data for CQ, but dose comparisons in older literature suggest using ≤2.3 mg/kg real weight.

RISK OF TOXICITY

The risk of toxicity is dependent on daily dose and duration of use. At recommended doses, the risk of toxicity up to 5 years is under 1% and up to 10 years is under 2%, but it rises to almost 20% after 20 years. However, even after 20 years, a patient without toxicity has only a 4% risk of converting in the subsequent year.

MAJOR RISK FACTORS

High dose and long duration of use are the most significant risks. Other major factors are concomitant renal disease, or use of tamoxifen.

SCREENING SCHEDULE

A baseline fundus examination should be performed to rule out preexisting maculopathy. Begin annual screening after 5 years for patients on acceptable doses and without major risk factors.

SCREENING TESTS

The primary screening tests are automated visual fields plus spectral-domain optical coherence tomography (SD OCT). These should look beyond the central macula in Asian patients. The multifocal electroretinogram (mfERG) can provide objective corroboration for visual fields, and fundus autofluorescence (FAF) can show damage topographically. Modern screening should detect retinopathy before it is visible in the fundus.

TOXICITY

Retinopathy is not reversible, and there is no present therapy. Recognition at an early stage (before any RPE loss) is important to prevent central visual loss. However, questionable test results should be repeated or validated with additional procedures to avoid unnecessary cessation of valuable medication.

COUNSELING

Patients (and prescribing physicians) should be informed about risk of toxicity, proper dose levels, and the importance of regular annual screening.

Assessment of parafoveal cone density in patients taking hydroxychloroquine in the absence of clinically documented retinal toxicity

PURPOSE

To measure cone density in patients taking hydroxychloroquine (HCQ), with no clinical evidence of maculopathy.

METHODS

Patients visiting for HCQ macular toxicity screening in the Besançon University Hospital Ophthalmology Department (France) were studied. They underwent routine examination including spectral-domain optical coherence tomography, fundus autofluorescence and multifocal electroretinogram to detect HCQ-induced retinal toxicity. Cone metrics (density, spacing and percentage of cones with six neighbours) were obtained using an adaptive optics camera (RTX1, Imagine Eyes, Orsay, France). The region of interest corresponded to a 0.3° × 0.3° square placed nasally and temporally at 2° of eccentricity from the fovea.

RESULTS

Forty eyes of 23 patients were studied. The majority of the patients (21/23) were female. They were aged from 25 to 60 years (mean age ± SD: 40.1 years ± 10). The cumulative dose for HCQ ranged from 24 to 2160 g (777 ± 558 g). None of them displayed HCQ toxicity on screening tests. Bivariate analysis showed moderate cone loss with escalating doses of HCQ (linear regression, r² = 0.23, p = 0.018). Cone spacing also increased with increasing cumulative dose (r² = 0.17, p = 0.008). Cone packing remained unchanged (p > 0.05). Multivariate analysis showed that age and cumulative dose were additive and independent factors of cone dropout.

CONCLUSIONS

In this pilot study, we observed moderate cone loss as HCQ cumulative doses increased. The early detection of parafoveal cone metric changes may represent the earliest sign of HCQ macular toxicity during screening.

Rapid Onset of Retinal Toxicity From High-Dose Hydroxychloroquine Given for Cancer Therapy

PURPOSE

To report rapid onset of retinal toxicity in a series of patients followed on high-dose (1000 mg daily) hydroxychloroquine during an oncologic clinical trial studying hydroxychloroquine with erlotinib for non-small cell lung cancer.

DESIGN

Retrospective observational case series.

METHODS

Ophthalmic surveillance was performed on patients in a multicenter clinical trial testing high-dose (1000 mg daily) hydroxychloroquine for advanced non-small cell lung cancer. The US Food & Drug Administration-recommended screening protocol included only visual acuity testing, dilated fundus examination, Amsler grid testing, and color vision testing. In patients seen at Stanford, additional sensitive screening procedures were added at the discretion of the retinal physician: high-resolution spectral-domain optical coherence tomography (OCT), fundus autofluorescence (FAF) imaging, Humphrey visual field (HVF) testing, and multifocal electroretinography (mfERG).

RESULTS

Out of the 7 patients having exposure of at least 6 months, 2 developed retinal toxicity (at 11 and 17 months of exposure). Damage was identified by OCT imaging, mfERG testing, and, in 1 case, visual field testing. Fundus autofluorescence imaging remained normal. Neither patient had symptomatic visual acuity loss.

CONCLUSIONS

These cases show that high doses of hydroxychloroquine can initiate the development of retinal toxicity within 1-2 years. Although synergy with erlotinib is theoretically possible, there are no prior reports of erlotinib-associated retinal toxicity despite over a decade of use in oncology. These results also suggest that sensitive retinal screening tests should be added to ongoing and future clinical trials involving high-dose hydroxychloroquine to improve safety monitoring and preservation of vision.

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.

Hydroxychloroquine screening practice patterns within a large multispecialty ophthalmic practice

PURPOSE

To determine provider compliance with hydroxychloroquine screening following the revised recommendations published in 2011 by the American Academy of Ophthalmology.

DESIGN

Evaluation of adherence to a screening protocol.

METHODS

Subjects were identified with hydroxychloroquine as a medication by electronic query at a large multispecialty ophthalmic practice. Patients were excluded if patients: (1) were screened by an outside physician; (2) lacked recorded height, weight, start date, or dosing; or (3) took hydroxychloroquine for malaria prophylaxis. Screening tests were stratified by ophthalmic subspecialty. Guidelines define proper screening as 1 subjective test-Humphrey visual field (HVF), and 1 objective test-spectral-domain optical coherence tomography (SD OCT), fundus autofluorescence (FAF), or multifocal electroretinography (mfERG). Adherence to guidelines was determined by categorizing practices as: (1) "appropriate"-consistent with guidelines; (2) "underscreened"-insufficient testing; or (3) "inappropriate"-no testing.

RESULTS

The study comprised 756 patients with a mean age of 56 years undergoing 1294 screening visits. Twenty-one patients received initial screenings outside the institution. Most common screening tests employed included SD OCT (56.6%), 10-2 HVF (55.0%), and Amsler grid (40.0%). Of the 735 initial screenings, 341 (46.4%) were appropriately screened, 204 (27.8%) underscreened, and 190 (25.9%) inappropriately screened. Of those who presented solely for screening (560), 307 (54.8%) were appropriately screened, 144 (25.7%) underscreened, and 109 (19.5%) inappropriately screened.

CONCLUSIONS

Of patients presenting for hydroxychloroquine screening, 54.8% of patients received appropriate evaluation, indicating lack of adherence to guidelines. Overall, SD OCT and 10-2 HVF were the preferred screening modalities, with FAF and mfERG less frequently ordered.

Scotoma analysis of 10-2 visual field testing with a red target in screening for hydroxychloroquine retinopathy

Objective

To quantify the variability of scotomas detected by 10–2 visual field (VF) testing with a red target in patients taking hydroxychloroquine without and with retinopathy.

Design

Retrospective review of clinical charts and VFs.

Methods

Twenty-four patients taking hydroxychloroquine without retinopathy, and eight patients taking hydroxychloroquine with retinopathy were tested in this study. Retinopathy was defined by annular scotomas on 10–2 VF testing with corroborative spectral domain optical coherence tomographic outer retinal changes and multifocal electroretinographic changes leading to cessation of hydroxychloroquine or chloroquine. Location and depth of scotoma points on 10–2 VF testing were recorded and their fates followed in serial, reliable 10–2 VFs performed with a red target over time. The main outcome measures for this study were the number of scotoma points and locations, percentage of persistent scotoma points, size of scotomas, location of scotomas, and percentage of scotomas deepening.

Results

A median of 3, interquartile range (IQR) (2, 5), scotoma points per VF occurred in patients without retinopathy. A median of 86%, IQR (77, 100), of these resolved on the subsequent field. For patients with retinopathy, a median of 50%, IQR (46, 79), resolved, a difference compared to patients without retinopathy that was significant (P=0.0158). The median percentage of scotoma points in the zone from 2° to 8° from fixation in eyes with retinopathy was 72%, IQR (54, 100), compared to 49%, IQR (40, 54), in eyes without retinopathy (P=0.0069). The number of persistent scotoma locations at the last visit was higher in eyes with retinopathy: 3, IQR (1, 3), versus 0, IQR (0, 1), in patients without retinopathy, P=0.0156.

Conclusion

Point scotomas are common and variable in 10–2 VF testing with a red target for hydroxychloroquine retinopathy in subjects without retinopathy. Scotoma points in eyes with retinopathy are less variable. The annular zone 2°–8° from fixation was useful for distinguishing the significance of scotoma points. Discriminating eyes with retinopathy from eyes without retinopathy is probably easier using the 10–2 VF with a white target than a red target.

Assessment of hydroxychloroquine maculopathy after cessation of treatment: an optical coherence tomography and multifocal electroretinography study

Objective

This study was conducted to evaluate the macular status of patients treated with hydroxychloroquine before and after cessation of treatment.

Methods

Forty-two patients with systemic lupus erythematosus underwent ocular examination based on visual acuity evaluation, optical coherence tomography retinal thickness measurements, and multifocal electroretinography (mfERG) records at first visit. The tests were repeated 6 months after treatment withdrawal and compared to the findings at their first visit.

Results

Mean visual acuity (measured in log minimum angle of resolution) of both eyes was statistically increased after hydroxychloroquine discontinuation (difference in means: 0.06 [P<0.0001] and 0.01 [P=0.003] for the right and left eyes, respectively). Retinal response amplitudes of central and peripheral areas were significantly improved for both eyes. The following values were observed for central responses: the difference in means was −19.9 (P<0.0001) and −13.6 (P<0.0001) for the right eye and the left eye, respectively; for peripheral responses, difference in means was −10.3 (P<0.0001) and −9.5 (P<0.0001) for right eye and left eye, respectively, after the 6-month examination. There were no statistically significant differences in the retinal thickness of patients after cessation of treatment. The visual acuity of the patients was correlated to central and peripheral mfERG responses (r=−0.53 [P<0.0001] and r=−0.53 [P<0.0001], for the right eye and the left eye, respectively).

Conclusion

The visual acuity of patients receiving hydroxychloroquine improves along with the amplitudes of the mfERG responses 6 months after discontinuation of the drug, but no difference in retinal thickness is identified.

Scotoma analysis of 10-2 visual field testing with a white target in screening for hydroxychloroquine retinopathy

OBJECTIVE

To quantify the variability of scotomas detected by 10-2 visual field (VF) testing in patients taking hydroxychloroquine without and with retinopathy.

DESIGN

Retrospective review of clinical charts and visual fields.

SUBJECTS

Twenty-one patients taking hydroxychloroquine without retinopathy, and nine patients taking hydroxychloroquine and one patient taking chloroquine with retinopathy.

METHODS

Retinopathy was defined by annular scotomas on 10-2 VF testing with corroborative spectral domain optical coherence tomographic outer retinal changes and multifocal electroretinographic changes leading to cessation of hydroxychloroquine or chloroquine. Location and depth of scotoma points on 10-2 VF testing were recorded and their fates followed in serial, reliable 10-2 VFs performed with a white target over time.

MAIN OUTCOME MEASURES

Number of scotoma points and locations, percentage of persistent scotoma points, size of scotomas, location of scotomas, and percentage of scotomas deepening.

RESULTS

A median of five, interquartile range (IQR) 3-8 scotoma points per VF occurred in patients without retinopathy. A median of 86%, IQR 63%-100% of these points resolve on the subsequent field. For patients with retinopathy, a median of 22%, IQR 10%-59% resolve. The median percentage of scotoma points in the zone 2-8 degrees from fixation in eyes with retinopathy was 79%, IQR 68%-85% compared to 60%, IQR 54%-75% in eyes without retinopathy (P=0.0094). Single-point scotomas were more common in eyes without than with retinopathy. Scotomas consisting of more than four contiguous scotoma points were generally indicative of retinopathy.

CONCLUSION

Point scotomas are common and variable in 10-2 VF testing with a white target for hydroxychloroquine retinopathy in subjects without retinopathy. The annular zone 2 to 8 degrees from fixation was useful for distinguishing the significance of scotoma points. Scotomas with more contiguous scotoma points were more often associated with retinopathy.

Hydroxychloroquine and chloroquine retinopathy: a systematic review evaluating the multifocal electroretinogram as a screening test

PURPOSE

To determine the validity of multifocal electroretinography (mfERG) as a screening tool for detecting chloroquine (Aralen, Sanofi Aventis, Bridgewater, NJ) (CQ) and hydroxychloroquine (Plaquenil, Covis Pharmaceuticals, Inc, Zug, Switzerland) (HCQ) retinal toxicity in patients using these medications. To evaluate the sensitivity and specificity of mfERG when compared with automated visual fields (AVFs), fundus autofluorescence (FAF), and optical coherence tomography (OCT).

CLINICAL RELEVANCE

The 2011 American Academy of Ophthalmology recommendations on screening for CQ/HCQ retinopathy recommended a shift toward more objective testing modalities. Multifocal electroretinography may be effective in detecting functional change before irreversible structural damage from CQ/HCQ toxicity.

METHODS

We performed a search for records reporting the use of mfERG for screening CQ/HCQ retinopathy in MEDLINE (PubMed and OVID), EMBASE, and Web of Science, and assessed these using the QUADAS-2 risk of bias tool. We conducted an analysis of 23 individual studies and their reported individual patient data (449 eyes of 243 patients) published from January 2000 to December 2014.

RESULTS

Multifocal electroretinography had the greatest proportion of positive test results, followed by AVF. The pooled sensitivity and specificity of mfERG were 90% (95% confidence interval [CI], 0.62-0.98) and 52% (CI, 0.29-0.74), respectively, with AVF as reference standard (13 studies). Sensitivity was high, but specificity was variable when OCT, FAF, and the positivity of 2 of 3 tests was used as the reference standard. When verified against AVF as the reference test, patients with a false-positive mfERG result received higher HCQ cumulative doses (1068 g) than patients with true-negative (658 g, P < 0.01) and false-negative (482 g, P < 0.01) results.

CONCLUSIONS

Multifocal electroretinography was shown to have a high sensitivity but variable specificity when verified against AVF, OCT, FAF, and a combination of tests. The greater average cumulative dose in the false-positive group compared with the true-negative group when mfERG was verified against AVF suggests that mfERG may have the ability to detect cases of toxicity earlier than other modalities. There is an unclear risk of bias in the available evidence, and future studies should adhere to Standards for Reporting of Diagnostic Accuracy reporting guidelines.

Regular examinations for toxic maculopathy in long-term chloroquine or hydroxychloroquine users

IMPORTANCE

According to evidence-based, expert recommendations, long-term users of chloroquine or hydroxychloroquine sulfate should undergo regular visits to eye care providers and diagnostic testing to check for maculopathy.

OBJECTIVE

To determine whether patients with rheumatoid arthritis (RA) or systemic lupus erythematosus (SLE) taking chloroquine or hydroxychloroquine are regularly visiting eye care providers and being screened for maculopathy.

DESIGN, SETTING, AND PARTICIPANTS

Patients with RA or SLE who were continuously enrolled in a particular managed care network for at least 5 years between January 1, 2001, and December 31, 2011, were studied. Patients' amount of chloroquine or hydroxychloroquine use in the 5 years since the initial RA or SLE diagnosis was calculated, along with their number of eye care visits and diagnostic tests for maculopathy. Those at high risk for maculopathy were identified. Logistic regression was performed to assess potential factors associated with regular eye care visits (annual visits in ≥3 of 5 years) among chloroquine or hydroxychloroquine users, including those at highest risk for maculopathy.

MAIN OUTCOMES AND MEASURES

Among chloroquine or hydroxychloroquine users and those at high risk for toxic maculopathy, the proportions with regular eye care visits and diagnostic testing, as well as the likelihood of regular eye care visits.

RESULTS

Among 18 051 beneficiaries with RA or SLE, 6339 (35.1%) had at least 1 record of chloroquine or hydroxychloroquine use, and 1409 (7.8%) had used chloroquine or hydroxychloroquine for at least 4 years. Among those at high risk for maculopathy, 27.9% lacked regular eye care visits, 6.1% had no visits to eye care providers, and 34.5% had no diagnostic testing for maculopathy during the 5-year period. Among high-risk patients, each additional month of chloroquine or hydroxychloroquine use was associated with a 2.0% increased likelihood of regular eye care (adjusted odds ratio, 1.02; 95% CI, 1.01-1.03). High-risk patients whose SLE or RA was managed by rheumatologists had a 77.4% increased likelihood of regular eye care (adjusted odds ratio, 1.77; 95% CI, 1.27-2.47) relative to other patients.

CONCLUSIONS AND RELEVANCE

In this insured population, many patients at high risk for maculopathy associated with the use of chloroquine or hydroxychloroquine are not undergoing routine monitoring for this serious adverse effect. Future studies should explore factors contributing to suboptimal adherence to expert guidelines and the potential effect on patients' vision-related outcomes.

Multifocal ERG Guiding Therapy in a Case of Hydroxychloroquine Premaculopathy

We report the case of a 28-year-old female treated for systemic lupus erythematosus with hydroxychloroquine (200 mg/day) for 11 years. She was visually asymptomatic, with normal fundus appearance, normal colour vision testing findings, 20/20 visual acuity in both eyes, and only mild central bilateral defects on 10-2 perimetry. Multifocal electroretinography (mfERG) showed low density values for ring 1 in both eyes. Because the patient had not previously responded to alternative treatments and in consultation with her physician, the hydroxychloroquine dose was reduced to 200 mg four days/week. Four serial mfERGs performed at 4, 18, 25, and 34 months after dose reduction showed a progressive improvement in the definition and density of the responses until they were normalized at the third mfERG (25 months after hydroxychloroquine dose reduction). The fourth and final mfERG at 34 months confirmed the recovery in both eyes. Perimetry defects were mostly normalized. These results demonstrate the importance of mfERG for the safe management of patients under long-term hydroxychloroquine treatment.

A comparison of structural and functional changes in patients screened for hydroxychloroquine retinopathy

PURPOSE

The aims of this retrospective study were to compare the results of recommended screening tests for hydroxychloroquine-related retinal toxicity and analyze disparities between the structural and functional findings.

METHODS

Thirty-four patients (31 women and 3 men) were included in the study. All were evaluated with standard automated perimetry using the 10-2 and/or 24-2 visual field program (Zeiss, Meditec), multifocal electroretinography (mfERG), spectral-domain optical coherence tomography (SD-OCT), and short-wavelength fundus autofluorescent imaging (SW-FAF). The results for the right eye from each patient were analyzed. Visual fields were classified as normal or abnormal based on pattern deviation plots, and mfERGs based on a comparison of R5 ring ratios to values from 20 controls. The SW-FAF images were examined for areas/rings of abnormal hypo- and/or hyperautofluorescence, and the SD-OCT line scans were classified as abnormal based on visual inspection and thickness measurements of the outer segment plus retinal pigment epithelial layer and total receptor layers compared to mean thicknesses from 35 controls.

RESULTS

Fifteen patients had abnormal results on at least one test; however, only two patients had abnormal results on all four tests. Excluding SW-FAF, seven of the 15 had abnormal visual fields, mfERG ring ratios, and SD-OCTs. The remaining eight had either abnormal mfERGs and/or visual fields and normal SD-OCTs. We found no evidence of abnormal SD-OCTs in the presence of normal mfERG and visual field results.

CONCLUSIONS

The findings suggest that functional deficits precede structural changes seen on SD-OCT in these patients.

Subjective and objective screening tests for hydroxychloroquine toxicity

OBJECTIVE

To compare subjective and objective clinical tests used in the screening for hydroxychloroquine retinal toxicity to multifocal electroretinography (mfERG) reference testing.

DESIGN

Prospective, single-center, case control study.

PARTICIPANTS

Fifty-seven patients with a previous or current history of hydroxychloroquine treatment of more than 5 years' duration.

METHODS

Participants were evaluated with a detailed medical history, dilated ophthalmologic examination, color fundus photography, fundus autofluorescence (FAF) imaging, spectral-domain (SD) optical coherence tomography (OCT), automated visual field testing (10-2 visual field mean deviation [VFMD]), and mfERG testing. We used mfERG test parameters as a gold standard to divide participants into 2 groups: those affected by hydroxychloroquine-induced retinal toxicity and those unaffected.

MAIN OUTCOME MEASURES

We assessed the association of various imaging and psychophysical variables in the affected versus the unaffected group.

RESULTS

Fifty-seven study participants (91.2% female; mean age, 55.7±10.4 years; mean duration of hydroxychloroquine treatment, 15.0±7.5 years) were divided into affected (n = 19) and unaffected (n = 38) groups based on mfERG criteria. Mean age and duration of hydroxychloroquine treatment did not differ statistically between groups. Mean OCT retinal thickness measurements in all 9 macular subfields were significantly lower (<40 μm) in the affected group (P < 0.01 for all comparisons) compared with those in the unaffected group. Mean VFMD was 11 dB lower in the affected group (P < 0.0001). Clinical features indicative of retinal toxicity were scored for the 2 groups and were detected in 68.4% versus 0.0% using color fundus photographs, 73.3% versus 9.1% using FAF images, and 84.2% versus 0.0% on the scoring for the perifoveal loss of the photoreceptor ellipsoid zone on SD-OCT for affected and unaffected participants, respectively. Using a polynomial modeling approach, OCT inner ring retinal thickness measurements and Humphrey 10-2 VFMD were identified as the variables associated most strongly with the presence of hydroxychloroquine as defined by mfERG testing.

CONCLUSIONS

Optical coherence tomography retinal thickness and 10-2 VFMD are objective measures demonstrating clinically useful sensitivity and specificity for the detection of hydroxychloroquine toxicity as identified by mfERG, and thus may be suitable surrogate tests.

Spatial differences in corneal electroretinogram potentials measured in rat with a contact lens electrode array

Purpose

It has been known for several decades that the magnitude of the corneal electroretinogram (ERG) varies with position on the eye surface, especially in the presence of focal or asymmetric stimuli or retinal lesions. However, this phenomenon has not been well-characterized using simultaneous measurements at multiple locations on the cornea. This work provides the first characterization of spatial differences in the ERG across the rat cornea.

Methods

A contact lens electrode array was employed to record ERG potentials at 25 corneal locations simultaneously following brief full-field flash stimuli in normally sighted Long-Evans rats. These multi-electrode electroretinogram (meERG) responses were analyzed for spatial differences in a-wave and b-wave amplitudes and implicit times.

Results

Spatially distinct ERG potentials could be recorded reliably. Comparing relative amplitudes across the corneal locations suggested a slight non-uniform distribution when using full-field, near-saturating stimuli. Amplitudes of a- and b-waves were approximately 3 % lower in the inferior quadrant than in the superior quadrant of the cornea.

Conclusions

The present results comprise the start of the first normative meERG database for rat eyes and provide a basis for comparison of results from eyes with functional deficit. Robust measures of spatial differences in corneal potentials will also support optimization and validation of computational source models of the ERG. To fully utilize the information contained in the meERG data, a detailed understanding of the roles of the many determinants of local corneal potentials will eventually be required.

Ocular toxicity and functional vision recovery in a patient treated with hydroxychloroquine

CASE REPORT

We report the case of a 64-year-old woman with rheumatoid arthritis and Sjögren's syndrome, treated during 48 months with hydroxychloroquine that was removed after an ophthalmological evaluation showed bilateral vision loss associated with paracentral scotoma in the visual field, fundoscopic macular pigmentary changes, and severely impaired central multifocal electrorretinogram (mfERG). Twelve months after treatment withdrawal, visual acuity and central mfERG had surprisingly improved. This is an unusual case of functional recovery after treatment withdrawal. We consider that central mfERG is a more sensitive test than pattern electrorretinogram in the detection of retinal toxicity and functional vision recovery after hydroxychloroquine treatment cessation.

Test-retest variability of multifocal electroretinography in normal volunteers and short-term variability in hydroxychloroquine users

PURPOSE

To determine measurement variability of N1P1 amplitudes and the R1/R2 ratio in normal subjects and hydroxychloroquine users without retinopathy.

DESIGN

Retrospective, observational study.

SUBJECTS

Normal subjects (n=21) and 44 patients taking hydroxychloroquine (n=44) without retinopathy.

METHODS

Multifocal electroretinography (mfERG) was performed twice in one session in the 21 normal subjects and twice within 1 year in the hydroxychloroquine users, during which time no clinical change in macular status occurred.

MAIN OUTCOME MEASURES

N1P1 amplitudes of rings R1-R5, the R1/R2 ratio, and coefficients of repeatability (COR) for these measurements.

RESULTS

Values for N1P1 amplitudes in hydroxychloroquine users were reduced compared with normal subjects by the known effect of age, but R1/R2 was not affected by age. The COR for R1-R5 ranged from 43% to 52% for normal subjects and from 43% to 59% for hydroxychloroquine users; for R1/R2 the COR was 29% in normal subjects and 45% in hydroxychloroquine users.

CONCLUSION

mfERG measurements show high test-retest variability, limiting the ability of a single mfERG test to influence a decision to stop hydroxychloroquine; corroborative evidence with a different ancillary test is recommended in a suspicious case.

Validation of the colour difference plot scoring system analysis of the 103 hexagon multifocal electroretinogram in the evaluation of hydroxychloroquine retinal toxicity

PURPOSE

To evaluate sensitivity, specificity and reproducibility of colour difference plot analysis (CDPA) of 103 hexagon multifocal electroretinogram (mfERG) in detecting established hydroxychloroquine (HCQ) retinal toxicity.

METHODS

Twenty-three patients taking HCQ were divided into those with and without retinal toxicity and were compared with a control group without retinal disease and not taking HCQ. CDPA with two masked examiners was performed using age-corrected mfERG responses in the central ring (Rc ; 0-5.5 degrees from fixation) and paracentral ring (Rp ; 5.5-11 degrees from fixation). An abnormal ring was defined as containing any hexagons with a difference in two or more standard deviations from normal (colour blue or black).

RESULTS

Categorical analysis (ring involvement or not) showed Rc had 83% sensitivity and 93% specificity. Rp had 89% sensitivity and 82% specificity. Requiring abnormal hexagons in both Rc and Rp yielded sensitivity and specificity of 83% and 95%, respectively. If required in only one ring, they were 89% and 80%, respectively. In this population, there was complete agreement in identifying toxicity when comparing CDPA using Rp with ring ratio analysis using R5/R4 P1 ring responses (89% sensitivity and 95% specificity). Continuous analysis of CDPA with receiver operating characteristic analysis showed optimized detection (83% sensitivity and 96% specificity) when ≥4 abnormal hexagons were present anywhere within the Rp ring outline. Intergrader agreement and reproducibility were good.

CONCLUSIONS

Colour difference plot analysis had sensitivity and specificity that approached that of ring ratio analysis of R5/R4 P₁ responses. Ease of implementation and reproducibility are notable advantages of CDPA.