- Email: [email protected]
Topical estrogen drops for glaucoma? A long way to go
Correspondence Bin Lu Department of Oral and Maxillofacial Surgery, Qindu Stomatology College, The Fourth Military Medical University, Xi’an, China Le Li KaiYu Tong Department of Health Technology and Informatics,
1069 Hong Kong Polytechnic University, Hong Kong, China Wen Wang Department of Psychosomatics, Xijing Hospital, The Fourth Military Medical University, Xi’an, China
doi:10.1016/j.mehy.2007.11.008
Topical estrogen drops for glaucoma? A long way to go Dear Editor, I read ‘‘topical estrogen drops may be a new alternative in the treatment of glaucoma’’ published in your magazine, and I disagree the author partly because of the following reasons. No definite evidence to prove the lowering IOP effect of Estrogen. Some of the existent studies showed a lowering effect of estrogen on IOP, but other studies made a conclusion to the contrary, that is estrogen had no effect on IOP [1,2]. The differences may due to the lack of randomized controlled study of high quality. In addition, the changes of central corneal thickness with the changes of estrogen level [3] made doctors to under- or over- estimate the IOP values. Local administration of estrogen may cost much. Uncu G. indicated that estrogen could decrease IOP while increase potential risk of dry eye syndrome [4]. Altintas O. got the same results in his study [5]. The bioavailability of topical estrogen drops may be low. The absorption of eye drops is severely limited by the relatively impermeable cornea. Estrogen with high lipid solubility will find much resistance crossing the corneal stroma. So pharmaceutical scientists will face many difficulties to produce effective estrogen eye drops. The population benefit from topical estrogen drops may be limited. Estrogen in topical drops may go to other organs with blood circulation and play its role, including stimulating the female reproductive organs and the development of secondary female sex characteristics. Undoubtedly, men without enough courage will not have a try. And it seems right to apply estrogen eye drops to doi:10.1016/j.mehy.2007.11.006
postmenopausal women, but is it also right to healthy women? Taking all above into consideration, we think that there is a long way to go before topical estrogen drops becomes a new alternative in the treatment of glaucoma.
References [1] Abramov Y, Borik S, Yahalom C, Fatum M, Avgil G, Brzezinski A, et al. Does postmenopausal hormone replacement therapy affect intraocular pressure? J Glaucoma 2005;14(4): 271–5. [2] Qureshi IA, Huang YB, Xi XR, Wu XD. Hormonal changes associated with menstrual cycle have no definite influence on ocular pressure. Proc Natl Sci Counc Repub China B. 1997;21(2):49–53. [3] Giuffre ` G, Di Rosa L, Fiorino F, Bubella DM, Lodato G. Variations in central corneal thickness during the menstrual cycle in women. Cornea 2007;26(2):144. ˘lu O. The effects [4] Uncu G, Avci R, Uncu Y, Kaymaz C, Develiog of different hormone replacement therapy regimens on tear function, intraocular pressure and lens opacity. Gynecol Endocrinol 2006;22(9):501–5. [5] Altintasß O, Caglar Y, Yu ¨ksel N, Demirci A, Karabasß L. The effects of menopause and hormone replacement therapy on quality and quantity of tear, intraocular pressure and ocular blood flow. Ophthalmologica 2004;218(2):120–9.
Hongbo Yin Xuyang Liu Ophthalmic Laboratories, West China Hospital, Sichuan University, No. 1, 4th Keyuan Road, Gaopeng Avenue, Chengdu, Sichuan 610041, China Tel.: +86 2885164066 E-mail address: [email protected] (H. Yin)
1069 Hong Kong Polytechnic University, Hong Kong, China Wen Wang Department of Psychosomatics, Xijing Hospital, The Fourth Military Medical University, Xi’an, China
doi:10.1016/j.mehy.2007.11.008
Topical estrogen drops for glaucoma? A long way to go Dear Editor, I read ‘‘topical estrogen drops may be a new alternative in the treatment of glaucoma’’ published in your magazine, and I disagree the author partly because of the following reasons. No definite evidence to prove the lowering IOP effect of Estrogen. Some of the existent studies showed a lowering effect of estrogen on IOP, but other studies made a conclusion to the contrary, that is estrogen had no effect on IOP [1,2]. The differences may due to the lack of randomized controlled study of high quality. In addition, the changes of central corneal thickness with the changes of estrogen level [3] made doctors to under- or over- estimate the IOP values. Local administration of estrogen may cost much. Uncu G. indicated that estrogen could decrease IOP while increase potential risk of dry eye syndrome [4]. Altintas O. got the same results in his study [5]. The bioavailability of topical estrogen drops may be low. The absorption of eye drops is severely limited by the relatively impermeable cornea. Estrogen with high lipid solubility will find much resistance crossing the corneal stroma. So pharmaceutical scientists will face many difficulties to produce effective estrogen eye drops. The population benefit from topical estrogen drops may be limited. Estrogen in topical drops may go to other organs with blood circulation and play its role, including stimulating the female reproductive organs and the development of secondary female sex characteristics. Undoubtedly, men without enough courage will not have a try. And it seems right to apply estrogen eye drops to doi:10.1016/j.mehy.2007.11.006
postmenopausal women, but is it also right to healthy women? Taking all above into consideration, we think that there is a long way to go before topical estrogen drops becomes a new alternative in the treatment of glaucoma.
References [1] Abramov Y, Borik S, Yahalom C, Fatum M, Avgil G, Brzezinski A, et al. Does postmenopausal hormone replacement therapy affect intraocular pressure? J Glaucoma 2005;14(4): 271–5. [2] Qureshi IA, Huang YB, Xi XR, Wu XD. Hormonal changes associated with menstrual cycle have no definite influence on ocular pressure. Proc Natl Sci Counc Repub China B. 1997;21(2):49–53. [3] Giuffre ` G, Di Rosa L, Fiorino F, Bubella DM, Lodato G. Variations in central corneal thickness during the menstrual cycle in women. Cornea 2007;26(2):144. ˘lu O. The effects [4] Uncu G, Avci R, Uncu Y, Kaymaz C, Develiog of different hormone replacement therapy regimens on tear function, intraocular pressure and lens opacity. Gynecol Endocrinol 2006;22(9):501–5. [5] Altintasß O, Caglar Y, Yu ¨ksel N, Demirci A, Karabasß L. The effects of menopause and hormone replacement therapy on quality and quantity of tear, intraocular pressure and ocular blood flow. Ophthalmologica 2004;218(2):120–9.
Hongbo Yin Xuyang Liu Ophthalmic Laboratories, West China Hospital, Sichuan University, No. 1, 4th Keyuan Road, Gaopeng Avenue, Chengdu, Sichuan 610041, China Tel.: +86 2885164066 E-mail address: [email protected] (H. Yin)