Without debate, this class of drug reigns supreme in the treatment of inflammatory eye diseases.
There are two main types of ophthalmic corticosteroids: those that are ketone-based, and one that is ester-based. Almost all the side effects—most notably posterior subcapsular cataracts and increased intraocular pressure—are minimal or absent with the ester-based formulation, and only occasionally problematic even with the ketone formulation. The most commonly prescribed ketone-based steroids are prednisolone and dexamethasone. The only representative of the ester-based class of steroids is loteprednol.
As a reflection of epidemiology, this class of drugs enjoys very widespread use. However, for reasons beyond our understanding, there continues to be perpetuated great fear, caution and reserve in the use of these wonderful drugs. Perhaps it is because of the potential negative effects they can have with long-term use, both topically and orally, or perhaps it reflects a lack of ample clinical experience. Perhaps it is because corticosteroids do have the potential to worsen some conditions if there is misdiagnosis, such as HSV keratitis or fungal keratitis. Whatever the case, when properly used, corticosteroids have the ability to rapidly suppress ocular inflammatory diseases, thus helping to restore health and normalcy to afflicted ocular tissues.
The reality is that almost all acute-onset ocular conditions and diseases are inflammatory in nature. Examples include: noninfectious conjunctivitis; the uveitides; episcleritis; inflamed pingueculae; chemotoxic keratoconjunctivitis; phlyctenular keratoconjunctivitis; contact lens associated red eye (CLARE); allergic conjunctivitis; giant papillary conjunctivitis; blepharitis; corneal infiltrates; rosaceaassociated blepharokeratoconjunctivitis; superior limbic keratoconjunctivitis; ocular trauma; recurrent corneal erosions; stromal herpetic keratitis; herpes zoster ophthalmic manifestations; Thygeson’s superficial punctate keratitis; glaucomatocyclitic crisis; microcystic edema; and a host of nonspecific inflammatory conditions.
In radical contradistinction, the indication for the use of an antibiotic is evidence of mucopurulent infection, or prophylaxis if there is a true need for such. As can readily be seen, we are much more likely to need to employ a corticosteroid drug compared to an antibiotic.
Since there are so many indications to use corticosteroids, we suggest the best way to gain an understanding of these drugs is to know the three or four occasions when their use alone is either absolutely or relatively contraindicated. Obviously, the likely therapeutic misadventure is to use a topical steroid in the face of epithelial herpes simplex keratitis. However, any seasoned clinician has had such an event occur.
Here’s a classic case: The nursing home called the ophthalmologist’s office (this could have been an O.D. office just as easily, but in keeping with the true story, this is how this case played out) explaining that Mrs. Jones has a painful red eye and would he please call in a prescription for an eye drop for her. He prescribed an antibiotic-steroid combination drug to be used q.i.d. After two weeks of this therapy, Mrs. Jones’ eye was no better, and in fact was steadily worsening. (It is pitiful that the nursing home waited two weeks to follow back up.) So, in two weeks, Mrs. Jones was brought to the office, where she was found to have an advanced case of HSK with reduced visual acuity.
Here’s what was done: the antibiotic- steroid was stopped (not tapered—you only need to consider tapering when treating an intrinsic inflammatory condition), and trifluoridine therapy was started (q2h for four days and then q.i.d. for one week). She recovered normal vision, and did just fine. Certainly the patient was considerably inconvenienced, but ultimately, no enduring harm was done. This case nicely reveals the reality of this therapeutic misadventure, and note that the eye did not fall out of the orbit!
Here are a few thoughts to consider:
First, you should never call in a prescription for a steroid or steroidcontaining eye drop, especially if it is a unilateral red eye.
Second, If the patient has a bacterial, fungal or Acanthamoeba infection, use of a steroid would be unwise and counterproductive— and yet this too happens occasionally, even in the best of hands.
Third, if there is a significant epithelial defect (not ordinary SPK) such as a corneal abrasion, corneal ulcer, etc., do not use a steroid alone.
Finally, and this is the relative contraindication: If the diagnosis is unknown, perhaps the steroid would be the best medicine, and perhaps not. We opine that if the diagnosis is clearly not one of the above three conditions, a steroid or combination antibiotic-steroid would probably well serve the patient.
Now, we must make a couple of significant modifications to the above three conditions when choosing to use a combination antibioticsteroid rather than a steroid alone:
- With HSV epithelial keratitis, any steroid or combination drug is still absolutely contraindicated.
- Many times, our patients with significant bacterial conjunctivitis have considerable associated conjunctival injection. We typically treat these with a combination drug. With this approach, we eradicate the bacteria and suppress the conjunctival inflammation concurrently, thus bringing rapid relief and cure to the patient. The teaching that steroids exacerbate infectious processes is true if used alone, but is of no significance if an effective antibiotic is simultaneously used. We almost always prescribe Zylet (loteprednol/tobramycin, Bausch & Lomb) q2h for two or three days, then just q.i.d. for four or five more days. We have done this many hundreds of times with complete success. Since there are no combination drugs with antifungal or anti-acanthamoeba properties, then both a pure steroid and antibiotic/steroid combination should be avoided in such conditions.
- What about significant epithelial defects? Many such epithelial defects are secondary to anterior stromal leukocytic infiltration, which cause the overlying epithelium to secondarily break down. This is commonly seen with peripheral corneal infiltrates and staphylococcal exotoxin epithelial compromise. These are primarily inflammatory conditions, but since there is significant secondary epithelial compromise, employing a combination drug is probably a wise choice. There are numerous examples in which a steroid (with antibiotic cover) can indeed potentiate re-epithelialization. As previously mentioned, if the diagnosis is uncertain, yet the condition is not representative of one of the above discussed contraindications, then a steroid or combination drug will most likely bring healing.
One example in which this would not be true would be chlamydial (adult inclusion) conjunctivitis, in which no topical eye drop is therapeutic. (Oral azithromycin dosed at one single dose of 1,000mg is the treatment of choice. No topical eye drops are indicated at all.)
One final caveat regarding whether to choose a pure steroid or a combination product in the context of corneal disease: If the corneal epithelium is intact, then using a pure steroid is usually appropriate, whereas if there is significant epithelial compromise, a combination drug such as Zylet would probably be wiser, or at least make the prescriber feel more comfortable.