Urological Medications & the Eyes
It is not uncommon for us to receive questions from patients and family physicians regarding the effects of commonly used urological medications on either vision or how they might affect surgery on the eyes. Below is a summary of 3 common classes of medications which can potentially interact with either vision or surgery.
As always, this information is not meant to be a substitute for expert consultation with your family physician, urologist or ophthalmologist. Please discuss any concerns you have with your physician(s).
Alpha Blockers and Intraoperative Floppy Iris Syndrome (IFIS)
Alpha blockers or frequently used for the treatment of benign prostatic hyperplasia. The mechanism of actionof alpha blockers is to relax the smooth muscle in the prostate but they also have effects on the alpha receptors in the bladder neck. These also blockers are located throughout the body including in the blood vessels (which explains why dizziness can sometimes occur) and they are also found in the eyes.
Intraoperative floppy iris syndrome is a complication that can occur during cataract surgery. Typically, the pupil needs to be able to dilate and contract normally during surgery for a safe procedure. Any of the alpha blockers can cause an issue with this by impairing contraction of the iris. The iris can prolapse through the surgical incisions and sometimes pupillary constriction can occur. This may result in iris trauma or posterior capsular rupture. IFIS is not exclusive to alpha blockers and can occur with several other medications including labetalol, zuclopenthixol and mianserin.
IFIS can occur in patients who are not taking alpha blockers but the incidence is only about 1 in 20 compared to approximately 3 out of every 4 patients taking an alpha blocker. Flomax (tamsulosin) is associated with the highest incidence of IFIS, it can occur with any of the other alpha blockers including terazosin (Hytrin), doxazosin (Cardura) and alfuzosin (Xatral/Uroxatral).
There are several unanswered questions regarding IFIS and alpha blockers. The time it takes for onset of IFIS to occur is unclear but is probably within one to 2 weeks of starting the medication. Alpha-blocker associated IFIS is probably not permanent but it is unclear how long before cataract surgery the medication should be stopped. There is considerable controversy regarding the benefits and timing of discontinuation of an alpha blocker prior to cataract surgery.
What should you do?
Inform your ophthalmologist that you are on an alpha-blocker if cataract surgery is being considered
It makes sense to withhold starting an alpha blocker until after cataract surgery if the surgery is imminent
Whenever possible stop the alpha-blocker 4 weeks prior to cataract surgery
PDE5 Inhibitors and Non-Arteritic Anterior Ischemic Optic Neuropathy (NAION)
Phosphodiesterase 5 inhibitors are the most commonly use medications to treat erectile dysfunction. They have block the breakdown of nitric oxide (important in producing erections) by inhibiting phosphodiesterase 5 which is an enzyme. Visual side effects can occur with these medications but they are rarely serious.
The most common visual side effect occurs with Viagra and is a mild transient loss of college termination (especially of blue's and greens). This is not blindness and it is completely reversible once the medication wears off after several hours. There is no loss of vision - just a change in the perception of certain colors in BOTH eyes. No special precautions are required if this occurs but patients who experience this side-effect and find it disturbing can switch to either Levitra or Cialis which have a lower incidence of alteration in color discrimination.
NAION is basically a 'stroke' or 'compartment syndrome' involving the optic nerve which can cause acute loss of vision. Unlike the more commonly encountered color changes, there is loss of vision. Most commonly, there is a dark shadow which may only involve one part of the visual field, frequently the part closest to the nose. In virtually all cases, the visual loss occurs in ONE eye only. The visual loss will often improve given time but can be permanent or progressive and there are no proven treatments.
The biggest risk factors for NAION are high blood pressure, hyperlipidemia, diabetes and ischemic heart disease - which coincidentally are the biggest risk factors for erectile dysfunction. There is no evidence that PDE5 inhibitors increase the risk of NAION. It is probable that the use of PDE5 inhibitors is conincidental and that the likely cause of NAION when it occurs in men taking PDE5 inhibitors is the underlying cardiovascular conditions which also produced the erectile dysfunction, not the medication itself. I should be emphasizeed that there had only been a few cases in the many millions of men who had taken PDE 5 inhibitors. The FDA has labelled it as "possibly causal".
What should you do?
If you have any change in colour perception, you may safely continue to use PDE5 inhibitors. You can request to try Cialis or Levitra as alternatives
Avoid PDE5 inhibitors if you already have NAION the FDA's concerns
If there is any loss of vision, discontinue the PDE5 inhibitors and see your doctor
Anticholinergics and Glaucoma
This class of medications is used to treat overactive bladder (OAB) and urinary urge incontinence. The mechanism of action is to block muscarinic receptors which are involved in bladder contraction and sensation. These receptors are found throughout the body, including in the bowels and eyes which can lead to side-effects such as constipation. These side-effects are reversible upon discontinuation of the medication.
Glaucoma is a problem of the eyes in which the pressure within the eye is increased. This can compress the retina and cause blindness if untreated. There are 2 basic mechanisms for this: (1) over production of intraocular fluid (OPEN angle glaucoma) or (2) blockage of the outflow of intraocular flow (CLOSED angle glaucoma - or acute angle closure glacoma (AACG). Anticholinergics can rarely cause problems for patients with ACUTE ANGLE CLOSURE GLAUCOMA. They have NO effect on patients with OPEN angle glacoma nor do they have any effect on patients who have definitively been treated for AACG using laser iridotomy.
Anticholinergics can further impair outflow of intraocular fluid leading to a rise in eye pressure. While closed angle glaucoma can rarely produce a loss of vision, there have been NO reported cases of visual loss stemming from the use of anticholinergics - even in patients with a history of closed angle glaucoma. There is a single case report of a patient with AACG who required urgent laser iridotomy after taking an anticholinergic. The risk of any visual side-effects in patients with AACG who have been treated is likewise very, very small. Therefore, while there is an acknowledged mechanism by which anticholinergics could potentially cause visual loss in patients with AACG, it has never been reported and is a very low probability event. In short, these medications appear safe for all patients except those with UNTREATED AACG.
What should you do?
It is safe to take anticholinergics if you have OPEN angle glaucoma or have had a laser iridotomy for closed angle glaucoma.
For patients with closed angle glaucoma, checking with your eye doctor before starting the medication is advisable.