Re: Does the shape and size of the eye differ between males and females?

Hi Katie,

I would really like to have a reference that clearly backs up what I am going to write but have not been able to find a sutitable reference. That is not to say one does not exist, I just have not found it. However, this is what I believe.

I do not think that eye size differs between adult males and females. Eyeballs are one of few organs that do not change in size much as one is growing. The reason I believe that males and females have relatively same size eyes is because in order to have good vision, the length (called axial length) of the eyeball has to be around 24 mm (roughly 1 inch). This accommodates the refractive power (ability to bend light) of the cornea and lens so it focuses on the retina. Adult men and women have equal corneal and lens refractive powers so the eyeball length has to be near equal.

Another thing is that highly myopic (nearsighted) and highly hyperopic (farsighted) folks have an eyeball that is either too long or too short. Keep in mind that we are talking about distances usually less than 1 mm. Since there are roughly equal amounts of myopes and hyperopes between males and females, their eyeballs have to be near identical.

There are of course other situations when a person's eyeball appears bigger but really is just protruding more (in the case of proptosis or exophthalmos), usually due to eye disease. Graves disease can cause protusion of the eyeball. Eye injury also can give appearance of bigger eye as well.

I hope I have answered your question. Best of luck to you!

Kenton L. McWilliams, O.D.