Begin at the beginning

All methods of managing ocular pain begin with a thorough history and physical exam to determine the underlying source of the patient's complaints. Because the etiology of ocular pain can vary from corneal involvement to retro-bulbar neuritis, it's essential to identify the primary tissue that is responsible. Then design a treatment plan to address the specific concerns.

Corneal pain

The most common type of pain, my clinical experience shows, is related to the cornea and its associated anterior segment structures. This can be the result of blunt trauma, chemical toxicity, inflammation or infection. Pain from corneal trauma (abrasion) can vary in severity from moderate to intolerable, depending on the patient's threshold.

Be aware that while the epithelial damage is the primary source of discomfort, the collateral involvement of the uveal tissue is commonly part of the overall presentation and you should treat it concurrently. The simplest and most successful way to manage pain from abrasions, foreign bodies, etc., is to utilize a bandage contact lens (BCL), topical antibiotic and NSAID. 

I recommend a high Dk lens as these lenses significantly greater healing and comfort.

Soak the lens in two drops of a fourth-generation fluoroquinolone and two drops of an NSAID. Let the lens soak in this mixture for several minutes before you place it on the eye and then write a script for the antibiotic at q.i.d. One study showed that if an abrasion is greater than a 10mm square area, therapy with either patching or a bandage lens will improve epithelial wound healing. However, smaller abrasions are not materially affected by either therapeutic methodology.

A paper from the National Abrasion Patching Study Group showed that overuse of NSAIDs can markedly delay wound healing (20% or greater by two days), but that appropriate use will reduce ocular pain by 40% or more. The practical solution for this dilemma is to give the patient a sample of a mast-cell stabilizer (unit dose) and have them use it q3-q4 until it runs out. This will give excellent surface control of pain and not interfere with wound healing because of the short duration of use.

Another important tool to consider in pain management of blunt trauma and its sequelae is the use of a cycloplegic to stabilize ciliary body spasm and improve the patient's overall comfort. I recommend either one to two drops of homatropine 5% at chairside or, if there is significant anterior chamber response, a prescription for hyaluronic acid-5% b.i.d. or t.i.d. Dosing depends on the patient's overall level of skin pigmentation (the drug is less effective in darkly pigmented patients). Follow up with the patient on this regimen the next day if possible, and no later than two days, so that you can make appropriate adjustments to the medical therapy.

The high Dk levels of the contact lenses allows the lens to usually stay in place until the corneal wound heals. Assess this by using Fluoro-Safe (Altaire Pharmaceuticals), a high molecular weight NaFl that will not penetrate the lens, but gives the practitioner an excellent view of the epithelial tissue.

Oral pain control

Oral pain control may be required in patients with severe discomfort or who are intolerant of the BCL system. Clinicians have two available pathways:

■ Use of a central nervous acting narcotic. This gives good control in most patients, but the response may vary due to differences in opioid receptor sensitivity. Two common side effects of narcotics are nausea/vomiting in sensitive patients, and drowsiness that prevents the operation of motor vehicles. Short-term use for ocular pain (never prescribe for more than three to four days) is not a significant concern in regards to addiction. The drug most commonly used in this category is Vicodin (acetaminophen and hydrocodone, Abbot Laboratories) (Schedule III 2.5-7.5mg). Most adults should take one tablet t.i.d. or q.i.d./p.o. depending on size.

■ Use of an oral NSAID. This group includes Ultram (tramadol, Ortho-McNeil) 50mg t.i.d./p.o. It has a similar level of pain management to Schedule III narcotics, but without the risk of drowsiness and nausea. I recommend this for patients who are active or must return to the work place while still under care.

A concern with NSAID use is the development of gastro-intestinal complications. Patients with a history of gastric concerns (ulcer, GERD, etc.) should avoid agents such as Ultram. Other drugs, such as Endo Pharmaceuticals' Percodan (acetylsalicylic acid and oxycodone) or Percoset (acetaminophen and oxycodone, are also available, but are used less frequently today due to the efficacy of the BCL and NSAID system that's become a relative standard of care.

If you cannot access oral narcotics, combination therapy (500mg acetaminophen and 600 mg ibuprofen) can be very useful in diminishing pain. The synergistic effect of the combination is superior to the use of a 1,000mg dose of either of the medications as a sole therapeutic agent.

Inflammatory pain

The type of pain associated with inflammation differs in character and duration from that seen in corneal trauma. In conditions such as uveitis, episcleritis and scleritis, the pain is typically "dull" and deeply seated in the eye or orbital area. The etiology is the release of inflammatory mediators such as leukotrienes, IL8s, cytokeines and prostaglandins. The involvement can be limited to the anterior segment in the form of an iritis/iridocyclitis, or extend to a vitritis, optic neuritis or endophthalmitis.

Pain management in these situations is related to appropriate diagnosis and the institution of anti-inflammatory therapy. This is administered most commonly as a topical intervention, but can be delivered via injection (Kenalog, triamcinolone, Bristol Meyers Squibb) or as oral therapy (prednisone). The severity of the disease and the patient's level of pain predicts which route of administration you chose.

For significant anterior uveitis, a q.1.h. dose is typically a good starting point. Follow the patient at day one or two after initiation of therapy.

The use of a steroid unguent at bedtime is also valuable in some more aggressive cases of disease. Therapy for inflammatory disease is almost always accompanied by the use of a cycloplegic. While homatropine 5% is the most commonly-used drug in this category, there is occasionally a patient who requires even greater stabilization of the ciliary muscle to relieve the "spasm" that is producing the pain. In that circumstance, scopolamine 1/4% is a good choice b.i.d., or atropine 1% b.i.d. in patients who are experiencing severe pain or who have significantly pigmented irises.

It is unusual to administer oral pain medication initially in patients with inflammatory pain for two reasons:

A First, it can mask the severity of the disease, which is an important clinical indicator.

A Second, I have seen patients decrease their topical therapy due to diminishing pain and cause an exacerbation of the problem.

One of the keys to successful management of this type of pain is to be aggressive at the outset regarding dosing. It's appropriate to start patients at q.1.h and then taper over seven to 10 days depending on severity. I like to discontinue the cycloplegic agent two to three days before the anticipated cessation of the steroid. This stops the affect on accommodation before therapy is over.

The herpes exception

Another type of inflammatory pain that varies from the typical mechanism is that of Herpes zoster ophthalmicus. The organism becomes embedded in the cranial nerve following initial exposure in childhood to the Varicella virus. Depletion of the immune system allows for a recrudescence of the disease. If it's ineffectively treated, it produces post-herpetic neuralgia, which can be extremely debilitating and in some instances result in an incapacitating level of pain. Therapy has been directed toward the active use of oral anti-virals (Valtrex (valacyclovir hydrochloride, GlaxoSmithKline), Famvir (famciclovir, Novartis) and Zovirax (acyclovir, GlaxoSmithKline)) in the early phases of the development of the disease. It's important to initiate therapy before the fourth clinical day or its efficacy against chronic pain is significantly reduced. If the pain breaks through to the post-ocular treatment period, then the use of agents such as Neurontin (gabapentin, Pfizer) for chronic analgesia have demonstrated success. But the dose must be gradually increased over several days to maximize efficacy.

Flexibility is key

One of the global considerations in pain management is to remember that every individual is different in their level of tolerance. Treatment needs to be crafted to the person in the chair. The ability to "tailor" your approach to pain management will significantly improve your patient relationships and increase your clinical success. OM

References available upon request.

Dr. Thimons is a nationally and internationally acclaimed speaker and serves as medical director at Ophthalmic Consultants.