Prattoy Bej , B.Optom

Fellow Optometrist, Dr. Shroff’s Charity Eye Hospital, New Delhi, India

Hormones are types of chemicals in multicellular organisms or in other ways the body’s chemical messenger which has various effects on the body like inhibition or stimulation of growth, mood swings, hunger cravings, control of the reproductive cycle etc.

The menstrual cycle which is also regulated by hormones basically by complex interaction of hormones (Luteinizing hormone, Follicle stimulating hormone, Estrogen and Progesterone). During the cycle the secretion of these hormones are at peak levels depending upon the phases of the menstruation. ⁽¹⁾

The changes in the level of the hormones can also affect the ocular structures. ⁽²⁾ Studies have shown that the ocular surface is an estrogen dependent unit. ⁽³⁾

Figure 1: The menstrual cycle
Image Courtesy: https://www.medcomic.com/medcomic/the-menstrual-cycle

Why consider menstruation during a proper ocular examination?

There are many answers to this question, many studies have been done regarding this.

Basically, the menstrual cycle is divided into two phases: the Follicular phase and the Luteal phase. ⁽⁴⁾ During the follicular phase the estrogen is at peak levels. As we discussed earlier the dependency of the ocular surface with estrogen. The impairment of dry eye related symptoms, the production and the stability of the tear film, inflammation of the ocular surface were much more during the follicular phase. ⁽¹⁾  

How it affects the anterior segment of eye:

• There are also some effects of hormones in the dimensional stability of the cornea during menstrual cycle. The steepening of horizontal and vertical meridians occurred at the emergence of the cycle, and flattening occurred after the ovulation phase. ⁽⁵⁾
• The IntraOcular Pressure (IOP) is somewhat related to the Central Corneal Thickness (CCT). ⁽⁶⁾  The central cornea is thinnest at the starting of the cycle and thickness increases at ovulation and during the termination of the cycle. ⁽⁷⁾

Figure 2: IOP and phases of menstruation
Image courtesy: https://d3i71xaburhd42.cloudfront.net/b473009a988bcabcae132b087e438325bcdf08ed/3-Figure2-1.png

• Uveitis occurs when the middle layer (the layer between the sclera and the retina) of the eye gets inflamed. ⁽⁸⁾  And there is significant increment in the sign and symptoms of acute anterior uveitis is seen during the late stages of the menstrual cycle. ⁽⁹⁾

How it affects the posterior segment of eye:

• Retina, the innermost light-sensitive part of the eye, ⁽¹⁰⁾ also known for being one of the most metabolically active tissues in the human body is supplied by a well-organized vascular system. ⁽¹¹⁾ Researchers have found that by examining with optical coherence tomography angiography (OCTA) that the deep retinal capillary plexus-perfusion density (DCP-PD) is decreased in the nasal and inferior area of ETDRS (Early Treatment of Diabetic Retinopathy Study) map during ovulatory phase. ⁽¹²⁾
• The neuroretinal rim or the optic cup disc ratio is an identifier of the glaucoma. ⁽¹³⁾ The neuroretinal rim area significantly decreased or the optic cup area were significantly higher during the luteal phase of the cycle. ⁽¹⁴⁾

So, during a proper eye examination of a healthy young woman, the menstrual phases should take into action due to the variation of hormones by an optometrist or by an ophthalmologist for better treatment.

References:

1.  Hormonal control of menstrual cycle. Available at https://www.britannica.com/science/menstruation/Hormonal-control-of-menstrual-cycle
2. How hormones can affect he vision. Available at https://www.aao.org/eye-health/tips-prevention/how-hormones-can-affect-eyes-vision
3. Versura P, Fresina M, Campos EC. Ocular surface changes over the menstrual cycle in women with and without dry eye. Gynecol Endocrinol. 2007 Jul;23 ⁽⁷⁾:385-90.
4. Reed, B. G., & Carr, B. R. (2015). The normal menstrual cycle and the control of ovulation.
5. KIELY, PATRICIA M.*; CARNEY, LEO G.†; SMITH, GEORGE‡ Menstrual Cycle Variations of Corneal Topography and Thickness, Optometry and Vision Science: October 1983 – Volume 60 – Issue 10 – p 822-829
6. Wei, W., Fan, Z., Wang, L., Li, Z., Jiao, W., & Li, Y. (2014). Correlation analysis between central corneal thickness and intraocular pressure in juveniles in Northern China: the Jinan city eye study. PloS one, 9(8), e104842. 
7. Giuffrè, Giuseppe PhD*; Rosa, Luigi Di MD*†; Fiorino, Fabio MD†; Bubella, Daniele Morreale PhD*; Lodato, Gaetano MD* Variations in Central Corneal Thickness During the Menstrual Cycle in Women, Cornea: February 2007 – Volume 26 – Issue 2 – p 144-146
8.   Uveitis. Available at https://www.nei.nih.gov/learn-about-eye-health/eye-conditions-and-diseases/uveitis
9. Sanghvi, C., Aziz, K., & Jones, N. P. (2004). Uveitis and the menstrual cycle. Eye, 18 ⁽⁵⁾, 451-454.
10.  Retina. Available at https://www.aao.org/eye-health/anatomy/retina-103
11.  Sun, Y., & Smith, L. E. (2018). Retinal vasculature in development and diseases. Annual review of vision science, 4, 101. 
12. Guo, L., Zhu, C., Wang, Z., Gao, Z., Zhang, Z., & Pan, Q. (2021). Retinal Vascular Changes during the Menstrual Cycle Detected with Optical Coherence Tomography Angiography. Journal of Ophthalmology, 2021.
13. Gandhi, M., & Dubey, S. (2013). Evaluation of the Optic Nerve Head in Glaucoma. Journal of current glaucoma practice, 7 ⁽³⁾, 106–114. https://doi.org/10.5005/jp-journals-10008-1146
14. Akar, M.E., Taskin, O., Yucel, I. and Akar, Y. (2004), The effect of the menstrual cycle on optic nerve head analysis in healthy women. Acta Ophthalmologica Scandinavica, 82: 741-745.