Is sex a risk factor for glaucoma?

Teresa Gomes, MD

Senior Specialist Registrar, Central Lisbon Hospital Centre (CHLC), Lisbon, Portugal.
For a proper discussion of sex as a risk factor for glaucoma, the first step is to accurately define the risk factor: "sex". 
What is sex? 
A search of the online Oxford Dictionaries yields the following:

Sex - noun. (chiefly with reference to people) sexual activity, including specifically sexual intercourse:

  • euphemistic a person’s genitals;
  • either of the two main categories (male and female) into which humans and most other living things are divided on the basis of their reproductive functions;
  • the fact of belonging to either the male or female sex;
  • the group of all members of either the male or female sex.
  • verb
  • determine the sex of.
Oxford, United Kingdom: Oxford University Press. [consulted on: February 24, 2014].
Therefore, we may divide sex as a risk factor for glaucoma into two major groups: as gender and as sexual activity.
Much has been published for many years, even decades, both on gender and on sexual activity and their influence on glaucoma.
Let us start with gender. The higher incidence of some types of glaucoma according to sex has been known for a long time. This is the case of primary angle-closure1,2,3, Fuchs' heterochromic cyclitis, normal-pressure glaucoma and pseudoexfoliative glaucoma, whose risk is higher in the female gender. On the other hand, primary congenital glaucoma and pigmentary glaucoma are more prevalent in males.
The larger group of primary open-angle glaucoma (POAG) does not show a distinctive prevalence according to gender, probably because in light of current knowledge it still includes a vast group of pathological states with different characteristics which have not yet been differentiated.
It is interesting to examine the reasons for the different prevalences. In some cases, the cause may be exclusively genetic, but in others it is related to morphological differences of the eye globe (narrow angle), or endocrine4 or vascular differences (normal-pressure glaucoma), which in turn are also genetically defined. 
It must be stressed that environment, in particular the different habits and therapeutics of men and women (e.g., anovulatory drugs taken by women and a higher risk of trauma/accidents in men), can also influence the results of prevalence studies. 

Regarding sex as an activity, several questions are frequently asked by patients in everyday clinical practice. Although the ophthalmologist may consider such questions as secondary, they are definitely important for many patients. Therefore, it makes sense to know how to answer questions such as:

  • Is sexual activity a risk factor for glaucoma? 
  • Are phosphodiesterase-5 inhibitors (e.g., Viagra®) a risk factor for disease progression?
  • Can glaucoma therapy disrupt sexual activity?
  • After glaucoma surgery, should sexual activity be restricted?
Cases reported over the years relating glaucoma to sexual intercourse only mention narrow-angle glaucoma5,6. It is much more difficult to establish a causal risk or benefit relation in POAG, since the disease has a very slow progression.  
Currently, phosphodiesterase-5 inhibitors are the first-line therapy for erectile dysfunction. Transient visual symptoms, such as photophobia and changes in color perception occur in 3–10% of men treated with sildenafil (Viagra®). Non-arteritic ischemic optic neuropathy has also been reported, but with a much lower incidence7. Only one case of angle-closure glaucoma after sildenafil therapy has been published in the literature8. Nothing has been reported on other types of glaucoma, such as POAG.
Several publications associate glaucoma therapy with erectile dysfunction, in particular systemic carbonic anhydrase inhibitors9 . Recent studies10 have failed to show a correlation between topical anti-glaucoma therapy (beta-blockers) and impotence. This is mainly because patients had an array of systemic diseases, especially of a cardiovascular and metabolic nature, which become confounding variables. The same happens with ongoing systemic therapies.
In terms of the potential association between glaucoma and erectile dysfunction, one study, also recent,11 has identified an association. However, here, too, in the population studied the prevalence of systemic diseases and therapies could contribute to increasing impotence in these patients, and so it is not possible to accurately establish a direct relation between glaucoma and erectile dysfunction.
Finally, it is worth mentioning the importance of limiting post-operative physical activity (including sexual activity) after glaucoma surgery, regardless of the surgical technique used. This could avoid complications such as: choroidal detachment, and trabecular-descemetic window rupture (in non-penetrating surgery).
In conclusion, sex and sexual activity are risk factors to consider when assessing, treating and advising our glaucoma patients.
2nd Edition - February 2014