Electroretinographic Findings in Thyroid Dysfunction*

Thyroid Hormone Effects on Sensory Perception, Mental Speed, Neuronal Excitability and Ion Channel Regulation

“…This is confirmed by the finding of increased amplitudes of chiefly the b-waves of the electroretinogram in hyperthyroidism and a decrease in hypothyroidism (59,60), suggesting that thyroid hormone influences retinal sensitivity to light. Since there is evidence that thyroid releasing hormone (TRH) in the circulation decreases the critical flicker fusion frequency (61) the effect could also be due to the enhanced TRH level in the investigated test persons.…”

The Human Fetal Retinal Pigment Epithelium: A Target Tissue for Thyroid Hormones

“…Patients with hypothyroidism may complain of nyctalopia and have reduced a and b waves by electroretinography, which normalize after thyroid hormone replacement. Conversely, a supernormal electroretinogram has been reported in patients with hyperthyroidism [3]. Possibly relevant to agerelated macular degeneration, experimentally induced hypothyroidism in rats increases choroidal vascular permeability [4].…”

“…Thyroid hormone (3,3),5-triiodothyronine, T 3 ) and/or alterations in thyroid function have been shown to have several different effects on visual function in both animals and 400 Ophthalmic Res 1999;31:399- 406 Duncan/Bailey/Baxter/Schwartz patients. After thyroidectomy in rats, rod outer segment turnover is reduced, suggesting T 3 effects on photoreceptors and/or retinal pigment epithelium (RPE) [1].…”

Electroretinogram in General Medicine

“…The starting point of our investigation was the notion that bioelectric activity is increased in hyperthyroidism and reduced in myxedema [Torrents el al., 1954[Torrents el al., , 1956Pearlman and Burian, 1964], This was also supported by experiments in animals using different hormones. We first examined [ Wirth and Stirpe, 1965a] 27 patients with thy rotoxic exophthalmus, 4 patients with thyro tropic exophthalmus and 1 thyrotoxic sub ject without exophthalmus, this one, how ever, being included in the first group.…”

“…Torrents el al. [1954] found subnormal ERG; Wirth and Stirpe [1965 a, b] supernormal, whereas Pearlman and Burian [1964] found a subnormal b-wave, which increased after treatment with ¿.-triiodothyronine. This vari ability in the findings mentioned above may be explained tentatively by the fact that the ERG could not be strictly dependent upon endocrine dysfunction but upon liver insuf ficiency, which interferes with the transport of vitamin A.…”