Novel imaging techniques for hydroxychloroquine retinopathy

Abstract

Hydroxychloroquine retinopathy is an increasingly recognized cause of iatrogenic, irreversible visual impairment due to the expanding use of hydroxychloroquine in combination with improvements in disease detection following advances in retinal imaging techniques. The prevalence of disease is estimated to be greater than 5% amongst individuals who have used the drug for 5 years or more. In addition to conventional imaging modalities, such as spectral-domain optical coherence tomography (OCT) and fundus autofluorescence (FAF), novel retinal imaging techniques such as en face OCT, OCT angiography, fluorescence lifetime imaging ophthalmoscopy, quantitative autofluorescence, and retromode imaging are capable of detecting structural changes in the retina. These novel retinal imaging techniques have shown promise in detecting earlier disease than is possible with current mainstream imaging modalities. Moreover, these techniques may identify disease progression as well as enabling functional correlation. In the future, these novel imaging techniques may further reduce the risk of visual loss from hydroxychloroquine retinopathy through the earlier detection of pre-clinical disease.

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

“…Definitions of hydroxychloroquine-induced retinal toxicity vary due to the use of different diagnostic techniques such as OCT and FAF, and the lack of objective assessment tools in previous studies. Modern imaging allows for more objective classification of retinopathy by severity and pattern, but variations in the interpretation of these tests still contribute to inconsistencies in toxicity definitions 34. Allahdina et al proposed a new staging system based on OCT findings: stage 1 includes minor changes limited to the parafoveal region; stage 2 includes clear localised changes in the parafoveal region; stage 3 includes extensive parafoveal changes; and stage 4 includes foveal involvement.…”

“…En face optical coherence tomography ( en face OCT) is a novel retinal imaging technique that has demonstrated the ability to detect reflectivity changes in cases of photoreceptor defects and assess the extent of retinopathy in a single image. 8 In addition, OCT angiography (OCTA) can detect decreased vascular density in the capillary plexus layer and has been proposed as a potential additional parameter of retinal toxicity. 9 These emerging techniques offer superior visualisation of the macular region, enabling identification of subclinical disease and detection of possible toxic alteration before irreversible damage occurs.…”

Causes and trends of late diagnosis in Korean patients with hydroxychloroquine retinopathy

“…The insufficient availability of sensitive tests such as SD-OCT has been found to affect a significant proportion of patients. SD-OCT is a valuable tool for detecting retinal changes in hydroxychloroquine retinopathy ( 7 ), and its unavailability before 2010 at our institution may remarkably hinder the timely identification of the condition. Efforts should be made to ensure the availability and utilization of such advanced imaging techniques in screening programs ( 7 ), particularly for patients at high risk of retinopathy (e.g., long-term hydroxychloroquine users and daily dose/body weight >5 mg/kg) ( 2 ).…”

Hydroxychloroquine Screening Guidelines: Best Evidence, Controversies, and Future Areas of Research

“…According to one grading scheme for retinopathy, toxicity can be broken down to early, moderate, and severe toxicity based on the extent of retinal damage. Early toxicity is defined as having ≤180 degrees of patchy photoreceptor defects around the fovea, moderate toxicity is defined as >180 degrees of photoreceptor defects around the fovea, and severe toxicity is defined as having combined RPE defects 16,17 . The first of the available screening tools is standard automated perimetry testing, such as Humphrey VF testing, which provides important subjective functional data on visual deterioration.…”

“…Early toxicity is defined as having ≤ 180 degrees of patchy photoreceptor defects around the fovea, moderate toxicity is defined as > 180 degrees of photoreceptor defects around the fovea, and severe toxicity is defined as having combined RPE defects. 16,17 The first of the available screening tools is standard automated perimetry testing, such as Humphrey VF testing, which provides important subjective functional data on visual deterioration. 10-2 VF measures 10 to 15 degrees from the fovea, allowing for sensitive detection of early changes within the macula.…”