Is 25 mmhg within the normal intraocular pressure for an adult?

NO. Typically not, the normal range is usaully between 7-21 mm hg. 25 may be normal for some people though and may not cause a problem, glaucoma. 25 may also be artifically elevated due to a thicker than average cornea (which may affect the measuremant of intraocular pressure), this can be a normal variant (thick cornea).