We thank Drs. Turner and Kerber for their supportive letter in the importance of the findings of our study published in the May issue of the journal, “Postmenopausal Hormone Therapy Increases Retinal Blood Flow and Protects the Retinal Nerve Fiber Layer.”
1 This study was designed to bring to light the significant beneficial role that estrogens play by increasing retinal blood flow and protecting the retinal nerve fiber layer in women. There is a large body of evidence indicating that estrogens have beneficial vasomotor effects in several vascular beds, and there is a growing body of evidence that they have protective and trophic effects on the neurons in the brain. However, our understanding of the role of estrogens in the retina and optic nerve is limited, and we are just seeing the tip of the iceberg.
We are pleased that Drs. Turner and Kerber have called gynecologists' and ophthalmologists' attention to the visual function of women who are chronically hypoestrogenemic. Particularly, we believe that this hypoestrogenemic state could be important in women who experience early menopause onset, premature ovarian failure caused by chemotherapy and radiotherapy, genetic disorders, and hypopituitarism,
2 and in women undergoing aromatase inhibitor or selective estrogen receptor modulator therapy used for treating or preventing the recurrence of breast cancer.
3 Women who are chronically hypoestrogenemic may be susceptible to impaired ocular blood flow, which is hypothesized to be a contributing factor in the etiology and progression of age-related macular degeneration
4 and glaucoma
5 and to the thinning of the retinal nerve fiber layer, which is a clinical feature of glaucoma.