Structural and Functional Characterization of the Retinal Effects of Hydroxychloroquine Treatment in Healthy Eyes

MICROVASCULATURE ALTERATIONS OF PERIPAPILLARY RETINA AND MACULA IN SYSTEMIC LUPUS ERYTHEMATOSUS PATIENTS WITHOUT OCULAR INVOLVEMENT BY OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY

PURPOSE

To evaluate microvasculature alterations of the peripapillary retina and macula and to assess whether the changes can detect preclinical retinopathy in systemic lupus erythematosus patients.

METHODS

Cross-sectional study of 32 systemic lupus erythematosus patients without retinopathy and 22 normal controls. Optical coherence tomography angiography was used to measure the microvasculature of the peripapillary retina and macula. Vessel densities (VD, %) and fractal dimensions of superficial capillary plexus (SCP) and deep capillary plexus were calculated.

RESULTS

Compared with controls, macular vessel densities of the whole image SCP (macular vessel density of SCP-wi) and macular vessel density of inferior SCP (macular vessel density of SCP-i) were significantly reduced in systemic lupus erythematosus patients ( P < 0.05). The peripapillary vessel densities (peripapillary vessel density [pVD]) of a 2.5-mm circle of SCP (pVD of SCP Φ2.5 ), pVD of SCP Φ3.5 , and pVD of inferior region of the inner circle of SCP (pVD of SCP-ii) were significantly reduced in patients treated with hydroxychloroquine >5 years. Macular vessel density of SCP-wi declined with age (β = -0.12; P < 0.01) and pVD of SCP-ii declined with hydroxychloroquine cumulative dose (β = -0.01; P < 0.01). Macular vessel density of SCP-i had the best discrimination power of 0.77 ( P < 0.01).

CONCLUSION

Systemic lupus erythematosus patients without ocular involvement had microvasculature alterations that were particularly evident in the SCP. Peripapillary retina microvasculature may be reduced in patients with longer hydroxychloroquine treatment.

Review of Retinal Imaging Modalities for Hydroxychloroquine Retinopathy

This review provides an overview of conventional and novel retinal imaging modalities for hydroxychloroquine (HCQ) retinopathy. HCQ retinopathy is a form of toxic retinopathy resulting from HCQ use for a variety of autoimmune diseases, such as rheumatoid arthritis and systemic lupus erythematosus. Each imaging modality detects a different aspect of HCQ retinopathy and shows a unique complement of structural changes. Conventionally, spectral-domain optical coherence tomography (SD-OCT), which shows loss or attenuation of the outer retina and/or retinal pigment epithelium-Bruch's membrane complex, and fundus autofluorescence (FAF), which shows parafoveal or pericentral abnormalities, are used to assess HCQ retinopathy. Additionally, several variations of OCT (retinal and choroidal thickness measurements, choroidal vascularity index, widefield OCT, en face imaging, minimum intensity analysis, and artificial intelligence techniques) and FAF techniques (quantitative FAF, near-infrared FAF, fluorescence lifetime imaging ophthalmoscopy, and widefield FAF) have been applied to assess HCQ retinopathy. Other novel retinal imaging techniques that are being studied for early detection of HCQ retinopathy include OCT angiography, multicolour imaging, adaptive optics, and retromode imaging, although further testing is required for validation.

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.

Rapid Macular Thinning is an Early Indicator of Hydroxychloroquine Retinal Toxicity

PURPOSE

To demonstrate rapid macular thinning as an early and objective sign of hydroxychloroquine (HCQ) retinopathy.

DESIGN

Retrospective case cohort.

SUBJECTS

Cohort of 301 long-term HCQ therapy patients at Kaiser Permanente Northern California who had a minimum of four optical coherence tomography (OCT) studies which included Early Treatment Diabetic Retinopathy Study (ETDRS) retinal thickness values over a minimum interval of four years.

METHODS

Creation of sequential retinal thickness plots to show the rate of change in macular thickness within ETDRS regions.

MAIN OUTCOME MEASURES

1) Identification of rapid macular thinning, 2) Comparison of patients with rapid thinning to those with stable macular thickness, and 3) Comparison of rapid thinning patients with and without conventional OCT or 10-2 visual field signs of HCQ toxicity.

RESULTS

Retina thinning in 219 stable patients on long-term HCQ therapy averaged 0.62 ± 0.45 (mean ± standard deviation) microns per year, while 82 patients showed a period of relatively linear rapid thinning with a loss of 3.75 ± 1.34 microns per year. Of the patients with rapid thinning, 38 eventually developed conventional OCT or 10-2 visual field signs of HCQ retinal toxicity. The cumulative retinal thinning in these patients was 25.1 ± 6.2 microns compared to 15.7 ± 4.0 microns in those without conventional toxicity (p < 0.01).

CONCLUSIONS

Retinal thickness remains stable for many years in most patients on long-term HCQ therapy, but after a critical point the retina may begin to thin rapidly. Sequential plots of inner and outer ETDRS ring macular thickness provide objective evidence of this early structural change several years before conventional signs appear. This approach can alert patients and prescribing physicians to potential retinal damage and uses readily available OCT measurements that could be automated by manufacturers for use in comprehensive eyecare settings.

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.