Psychophysical measures of visual function and everyday perceptual experience in a case of congenital stationary night blindness

Abstract

An appreciation of the relation between laboratory measures of visual deficit and everyday perceptual experience is fundamental to understanding the impact of a visual condition on patients and so to a fuller characterization of the disorder. This study aims to understand better the interpretative processes by which modified sensory information is perceived by a patient with congenital stationary night blindness and the adaptive strategies that are devised to deal with their measurable visual loss. Psychophysical measurements of temporal resolution, spectral sensitivity, and color discrimination were conducted on a 78-year-old male patient with the condition, who was also interviewed at length about the ways in which his diagnosis affected his daily life. Narrative analysis was employed to identify the relation between his subjective perceptual experiences and functional deficits in identifiable components of the visual system. Psychophysical measurements indicated a complete lack of rod perception and substantially reduced cone sensitivity. Two particular effects of this visual loss emerged during interviews: 1) the development of navigational techniques that relied on light reflections and point sources of light and 2) a reluctance to disclose the extent of visual loss and resulting lifelong psychosocial consequences. This study demonstrates the valuable complementary role that rich descriptive patient testimony can play, in conjunction with laboratory and clinical measurements, in more fully characterizing a disorder and in reaching a more complete understanding of the experience of vision loss. It also evidences the particular suitability of filmmaking techniques as a means of accessing and communicating subjective patient experience.

Collaborative Research and Development of a Novel, Patient-Centered Digital Platform (MyEyeSite) for Rare Inherited Retinal Disease Data: Acceptability and Feasibility Study

“…Difficulty accessing IRD data is further compounded by the lack of publicly available natural history information for specific gene mutations relevant to IRD and poor knowledge regarding the correlation between clinical observations (objective measures) and first-hand experiences of IRD reported by the affected people (subjective measures) [ 9 ]. The incidence of the early stage disease remaining undetected or being misdiagnosed [ 10 ] because of lack of data makes it more difficult to ascertain the prevalence of these diseases, especially at a genetic level.…”

Überblick über die kongenitale stationäre Nachtblindheit mit überwiegend normalem Fundus

“…Aber dieses Phänomen findet sich bei vielen Kleinkindern und so ist es schwierig, das Krankheitsbild der CSNB zu erkennen. Oft zeigt sich aber, dass sich betroffene Jugendliche anders verhalten als Gleichaltrige [3]. Ein betroffener Patient berichtete über Einschränkungen insbesondere bei sozialen Aktivitäten dieser Altersgruppe wie Orientierungsschwierigkeiten in schlecht beleuchteten Kinosälen, Fahrradfahren bei Dämmerung, nicht auffindbares Schlüsselloch bei schwacher Beleuchtung etc.…”

“…Ein betroffener Patient berichtete über Einschränkungen insbesondere bei sozialen Aktivitäten dieser Altersgruppe wie Orientierungsschwierigkeiten in schlecht beleuchteten Kinosälen, Fahrradfahren bei Dämmerung, nicht auffindbares Schlüsselloch bei schwacher Beleuchtung etc. und daher Isolierung von gleichaltrigen Jugendlichen [3].…”