The evidence

Contrast sensitivity is a well-studied visual function with uses well beyond mould. This page sets out, for each area, what research has established, what it has not, and how MouldVision uses it. Numbers in brackets refer to the list at the end.

What contrast sensitivity is

Contrast sensitivity is the ability to see faint differences in shade. It is measured with patterns of bars or letters that become progressively fainter, at several bar widths. It depends on the optics of the eye and on processing in the retina, optic nerve and brain, and it often reveals changes that a standard letter chart, which uses black letters on white, does not [1–4].

By area of use

Eye health and ageing

Established
Contrast sensitivity declines with age and with cataract, glaucoma, macular disease and diabetic eye disease, and different diseases reduce it in different proportion to acuity [3, 4]. In a 2024 study of 1,159 adults, lower contrast sensitivity and larger differences between the eyes were associated with worse vision-related quality of life, independent of acuity [5].
Not established
The same study found a contrast chart on its own was not sensitive or specific enough to screen for eye disease [5].
How MouldVision uses it
The "Worth an eye check" headline sends people to an optometrist when easy patches are missed or a difference between the eyes repeats. The app never names an eye disease.

Optic nerve and neurological conditions

Established
Low-contrast vision is sensitive to optic nerve involvement in multiple sclerosis and is used alongside other measures to monitor it [6]. Contrast sensitivity reflects the visual pathway as well as the eye [2, 4].
Not established
A consumer contrast test is not a diagnostic or monitoring tool for any neurological condition.
How MouldVision uses it
Listed in every report as one of the many causes of a low result.

Metals, tobacco and other neurotoxicants

Established
In the Beaver Dam Offspring Study, 1,983 middle-aged adults were followed for ten years; those with the highest cadmium levels were about 40 % more likely to develop contrast sensitivity impairment, an effect largely shared with smoking, the main source of cadmium. Lead was not associated [7]. Water-borne biotoxins from harmful algal blooms have been associated with contrast deficits in exposed cohorts [8, 9].
Not established
These are group-level associations. They do not allow any individual result to be attributed to an exposure.
How MouldVision uses it
Context in the report's environmental section, and questionnaire items on smoking, solvents and pesticides, so research data can account for them.

Water-damaged buildings and mould

Established
Studies of occupants of water-damaged buildings have reported lower group contrast sensitivity, most consistently at middle bar widths [10, 11]. A NIOSH study found lower values at every bar width among staff of a severely water-damaged school than at a comparison school [11]. A 2026 comparison of four methods found the original handheld chart did not separate exposed people from controls, while digital tests did [12]. The Australian Mould Guideline 2026 sets out how indoor mould is assessed, interpreted and managed [14].
Not established
No validated biomarker or diagnostic test exists for mould-related illness [13]. The NIOSH investigators advised against using contrast sensitivity to evaluate individual mould-exposed people, citing weaknesses in earlier studies [11]. Digital tests remain investigational [12].
How MouldVision uses it
As a careful, fully recorded digital instrument for research and personal tracking, read beside building results, never as evidence of exposure. Building questions go to building assessment [14].

Everyday function, falls and night driving

Established
Reduced contrast sensitivity is a risk factor for falls in older people [16]. In a night-driving simulator, contrast sensitivity predicted how far away hazards were detected when standard acuity did not [17]. Among drivers over 70, contrast loss often occurred with normal acuity and was linked to avoiding night driving [18]. A Cochrane review found acuity alone is only weakly linked to crash risk [19].
Not established
No jurisdiction uses a contrast sensitivity cut-off for licensing; Australian standards assess acuity and visual fields [20].
How MouldVision uses it
A questionnaire item on night and glare driving; advice to see an optometrist if night driving has become harder. No fitness-to-drive judgement.

The exposome and healthy ageing

Established
The exposome is the sum of environmental exposures across a life, much of it indoors [21]. Indoor dampness and mould are a recognised, preventable risk to respiratory health [15]. Contrast sensitivity is an established marker of visual ageing [3].
Not established
No study has shown that tracking contrast sensitivity at home changes health outcomes, or that changes in it predict healthspan.
How MouldVision uses it
A personal baseline, repeated every few months, recorded with its test conditions and read beside what is happening in the home: the approach described in the NIIM 2026 keynote [22].

How the test itself is built

Sine-wave gratings at 1.5, 3, 6, 12 and 18 cycles per degree in the layout of the original contrast charts [1], drawn in linear luminance on a mid-grey background, sized from the phone's pixel density and a camera-measured viewing distance. Every patch shown and every answer given is recorded with the conditions, version numbers and an integrity check. Software verification is printed on every report; physical measurement and clinical validation are reported as not yet performed until they are [2]. The method explainer has the detail.

References

  1. Ginsburg AP. A new contrast sensitivity vision test chart. Am J Optom Physiol Opt. 1984;61(6):403–407.
  2. Pelli DG, Bex P. Measuring contrast sensitivity. Vision Res. 2013;90:10–14. doi:10.1016/j.visres.2013.04.015
  3. Owsley C. Contrast sensitivity. Ophthalmol Clin North Am. 2003;16(2):171–177.
  4. Xiong YZ, Kwon M, Bittner AK, Virgili G, Giacomelli G, Legge GE. Relationship between acuity and contrast sensitivity: differences due to eye disease. Invest Ophthalmol Vis Sci. 2020;61(6):40. doi:10.1167/iovs.61.6.40
  5. Flaharty K, Niziol LM, Woodward MA, et al. Association of contrast sensitivity with eye disease and vision-related quality of life. Am J Ophthalmol. 2024;261:176–186. doi:10.1016/j.ajo.2024.01.021
  6. Balcer LJ, Baier ML, Cohen JA, et al. Contrast letter acuity as a visual component for the Multiple Sclerosis Functional Composite. Neurology. 2003;61(10):1367–1373.
  7. Paulsen AJ, Schubert CR, Johnson LJ, et al. Association of cadmium and lead exposure with the incidence of contrast sensitivity impairment among middle-aged adults. JAMA Ophthalmol. 2018;136(12):1342–1350. doi:10.1001/jamaophthalmol.2018.3931
  8. Hudnell HK, House D, Schmid J, et al. Human visual function in the North Carolina clinical study on possible estuary-associated syndrome. J Toxicol Environ Health A. 2001;62(8):575–594.
  9. Shoemaker RC, Hudnell HK. Possible estuary-associated syndrome: symptoms, vision, and treatment. Environ Health Perspect. 2001;109(5):539–545.
  10. Shoemaker RC, House DE. Sick building syndrome (SBS) and exposure to water-damaged buildings: time series study, clinical trial and mechanisms. Neurotoxicol Teratol. 2006;28(5):573–588.
  11. Thomas G, Burton NC, Mueller C, Page E, Vesper S. Comparison of work-related symptoms and visual contrast sensitivity between employees at a severely water-damaged school and a school without significant water damage. Am J Ind Med. 2012;55(9):844–854. doi:10.1002/ajim.22059
  12. Jimenez-Barbosa IA, Di Lizio S, Ahn SB, et al. Assessment of visual contrast sensitivity in biotoxin-exposed individuals using four testing methods. Ann Med. 2026;58(1):2646821. doi:10.1080/07853890.2026.2646821
  13. American College of Medical Toxicology. Position statement: medical toxicology considerations in the diagnosis and treatment of patients with concerns about mold-related inhalation exposures. 2025.
  14. Neumeister-Kemp HG, Jones CL, Salthammer T, Burton L, Morawska L. Australian Mould Guideline (AMG) 2026: best practice guideline, a hygiene and risk-based framework for the assessment, interpretation, and management of indoor mould. Indoor Air 2026, Singapore, 14–18 June 2026. eprints.qut.edu.au/266288
  15. World Health Organization. WHO guidelines for indoor air quality: dampness and mould. Copenhagen: WHO Regional Office for Europe; 2009.
  16. Lord SR, Dayhew J. Visual risk factors for falls in older people. J Am Geriatr Soc. 2001;49(5):508–515.
  17. Jones PR, Ungewiss J, Eichinger P, et al. Contrast sensitivity and night driving in older people: quantifying the relationship between visual acuity, contrast sensitivity, and hazard detection distance in a night-time driving simulator. Front Hum Neurosci. 2022;16:914459. doi:10.3389/fnhum.2022.914459
  18. Spreng L, Favrat B, Borruat FX, Vaucher P. Cross-sectional study assessing the addition of contrast sensitivity to visual acuity when testing for fitness to drive. BMJ Open. 2018;8(1):e018546. doi:10.1136/bmjopen-2017-018546
  19. Desapriya E, Harjee R, Brubacher J, et al. Vision screening of older drivers for preventing road traffic injuries and fatalities. Cochrane Database Syst Rev. 2014;(2):CD006252. doi:10.1002/14651858.CD006252.pub4
  20. Austroads, National Transport Commission. Assessing Fitness to Drive for commercial and private vehicle drivers. Sydney: Austroads; 2022.
  21. Wild CP. Complementing the genome with an "exposome": the outstanding challenge of environmental exposure measurement in molecular epidemiology. Cancer Epidemiol Biomarkers Prev. 2005;14(8):1847–1850.
  22. Jones CL. Hiding in plain sight: the indoor exposome of mould, air and the health risk in the rooms we live in [keynote]. 11th Annual NIIM Symposium: Future-Proofing Health; 10–11 September 2026; Richmond, VIC.
Take the testQuestionsMethod explainer (PDF)