Document Type



Doctor of Philosophy


Physiological Optics

Date of Defense


Graduate Advisor

Carol K. Peck, Ph.D.


Carol K. Peck, PhD

Carl J. Bassi, PhD

William G. Bachman, OD, MS

George Taylor, PhD


PURPOSE: The chromatic contribution to brightness perception was compared in males and females. METHODS: Direct brightness matching (DBM) and heterochromatic flicker photometry (HFP) were used to measure relative luminous efficiency, and DBM/HFP ratios were predicted to be higher for females than males on repeated measures and for each "primary" color. No gender differences were predicted in DBM or HFP measures. Within-females effects of estradiol (E2) and progesterone (PG) levels, contraceptive use, and menstrual cycle phase were also investigated. It was expected that E2 would directly predict DBM/HFP ratios and that PG would antagonize that relationship. Based on that prediction, DBM/HFP ratios would be at a maximum during the ovulatory phase, intermediate during the menstrual phase and minimum during the luteal phase. No effects were predicted for DBM or HFP measures. RESULTS: DBM/HFP ratios were significantly higher for female subjects than male subjects. Contraceptive use had no effect on overall DBM/HFP ratios. There were limited effects of hormone levels, menstrual cycle phase and contraceptive use on DBM/HFP ratios and on DBM and HFP measures analyzed separately. However, hormone effects on DBM/HFP ratios and DBM measures at 650 nm agree with previous findings involving long-wavelength sensitive (L-) cone mechanisms. CONCLUSIONS: The present findings supporting a female advantage in chromatic contribution to brightness are robust. The significant results are discussed in the context of previous findings suggesting organizational and short-term effects of ovarian steroid hormones.

OCLC Number


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