The effect of hypothyroidism on color contrast sensitivity: a prospective study

Conclusions starts It is a novel finding…. Let me be the first to shout from the rooftops that what is novel is only its being mentioned in an academic/medical paper. It has most certainly been mentioned here on HU/TUK.

Calming down, it is truly excellent news when these things are written up and others - academic and medical - might realise that it is a very real symptom and not the figment of some imagination.

Eur Thyroid J. 2015 Mar;4(1):43-7. doi: 10.1159/000371549. Epub 2015 Feb 7.

The effect of hypothyroidism on color contrast sensitivity: a prospective study.

Cakir M1, Turgut Ozturk B2, Turan E1, Gonulalan G1, Polat I3, Gunduz K4.

Author information

• 1Division of Endocrinology and Metabolism, Konya Necmettin Erbakan University, Konya, Turkey.

• 2Department of Ophthalmology, School of Medicine, Selcuk University, Konya, Turkey.

• 3Departments of Internal Medicine, Konya Necmettin Erbakan University, Konya, Turkey.

• 4Departments of Ophthalmology, Meram School of Medicine, Konya Necmettin Erbakan University, Konya, Turkey.



Thyroid hormone has been shown to control retinal cone opsin expression, the protein of color vision, in adult rodents.


The aim of this study was to evaluate the effect of hypothyroidism on color contrast sensitivity in adult overt hypothyroid patients.


Thirty-eight overt hypothyroid (31 females, 7 males) subjects and 20 euthyroid (16 females, 4 males) controls were studied prospectively. Color vision examination was performed by Chromatest, a software program analyzing the tritan (blue-yellow) color contrast threshold (tritan CCT) and protan (red-green) color contrast threshold (protan CCT). Color contrast sensitivity analyses of hypothyroid subjects were performed on admission and after L-thyroxine treatment when biochemical euthyroidism was achieved.


After a median period of 90 (90-210) days, 24 (19 females, 5 males) patients were euthyroid and eligible for a second color vision examination. Baseline tritan CCT and protan CCT values were significantly higher in the hypothyroid group compared to euthyroid controls, which clinically translates into impaired color contrast sensitivity (p < 0.001 and p < 0.001, respectively). There was a significant decrease in tritan CCT (p = 0.002) and protan CCT (p < 0.001) values in the hypothyroid group after euthyroidism was achieved, which denotes improvement in color contrast sensitivity.


It is a novel finding of the current study that color contrast sensitivity is impaired in hypothyroidism and significantly improves after euthyroidism is achieved.


Color vision; Cone; Hypothyroidism; Opsin; Thyroid




Will the full paper be available in future? Hope so.

5 Replies

  • Hooray!

    Yes indeed, we've discussed this before on here, so we don't need them to tell us it's true. But as you say, it is good to see it being made 'official'.

  • Lets hope this circulates in the Endocrinology Circle and not just filed away somewhere.

  • So that's my late teens, early twenties, before I had any idea I was becoming hypo. I lost my colour vision a few times. It was most bizarre as for about ten minutes the world turned monochrome. I recall that I could not look up as the sky was too bright for me to tolerate. Strange. It only happened a couple of times over a fortnight and I'd not made a connection. However, it was decades before I discovered that my tiredness and brain fog was due to hypothyroidism. I did not gain weight at all for many years and was pretty skinny. (Not the case now!)

  • Complete loss of colour vision happened to me too. Oddly it happened after diagnosis and starting thyroxine. As you say, quite bizarre to find oneself suddenly catapulted into a monochrome world. As a designer of textiles and other colour related arty things for most of my life, I found it quite distressing too. Thankfully all my thyroid related vision issues resolved once on the right type and dose of medication.

  • There is an article published in 2011 entitled

    'Thyroid affects colour vision

    Thyroid hormone controls the eye's visual pigments throughout life'

    You can read it in the research section of Thyroid UK main website here

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