Patient experience in retinitis pigmentosa and Choroideremia- a concept elicitation study in 17 patients based on...

Retinitis pigmentosa (RP) and Choroideremia (CHM) are rare inherited retinal diseases (IRDs) that can lead to severe visual impairment or blindness. Despite different underlying genetic pathways, they have many progression patterns in common, first affecting the more peripheral retina and later advancing toward the central retina. Early symptoms of both diseases include night blindness, difficulty adjusting to changing levels of light, and difficulty seeing in poor contrast. This is followed by progressive loss of the peripheral visual field in daylight, and eventually blindness. Currently, hardly any studies based on interviews that describe symptom experience and impact exist. In this concept elicitation study, we conducted qualitative interviews to identify the symptoms experienced by RP (n = 12) and CHM (n = 5) patients, and to understand the impact of symptoms on patients' lives.

Among the 14 symptoms reported, poor night vision/night blindness, difficulty seeing in bright light, and difficulty seeing in low/dim light were experienced by all participants. Over 50% of participants in either condition reported difficulty adapting from bright to dark and vice versa, poor peripheral vision, poor contrast sensitivity, poor distance vision, and poor visual acuity. Symptoms had a significant impact on activities of daily living. Most commonly impacted were the ability to navigate and the use of digital screens (n = 17/17, 100%) as well as physical functioning and work/school-related activities (n = 16/17, 94.1%). These impacts were often exacerbated by environmental factors. For instance, all participants reported this for navigation. Additionally, most participants (n = 13/17, 76.5%) reported impacts on emotional well-being. Concept saturation was shown for the RP sample (n = 12) and the combined sample (n = 17), i.e., all concepts reported were spontaneously mentioned in the first 3 sets of interviews. This suggests that further interviews would be unlikely to yield any new symptom concepts.

The patient interviews provided insight into the patient experience of RP and CHM and formed the basis for developing a combined conceptual model of RP and CHM disease experience, suitable to serve as basis for future patient reported and performance outcome measures. Testing in larger samples, especially in CHM, is recommended to further evaluate content validity of these preliminary findings.