Dry Eye Dx and Tx

Managing Neurotrophic Ulcers

By Richard B. Mangan, OD, FAAO

Neurotrophic keratopathy is a degenerative condition of the cornea that results from sensory denervation or hypesthesia. When the neurosensory feedback loop is affected in this way, both blink rate and reflex tear production are significantly reduced. If left unchecked, this may ultimately lead to epithelial breakdown and secondary complications such as infection, ulceration, melting, and even perforation.

Treat With TAPE

When dealing with a neurotrophic defect, remember the acronym “TAPE” to help you succeed in its management.

T = Tetracyclines The tetracyclines inhibit cellular and extra cellular levels of pro-inflammatory mediators such as IL-1B and MMP-9. I typically prefer a 50mg dose initially. In most cases, it is better tolerated than a 100mg dose and is usually less costly.

A = Autologous Serum Unlike artificial tears, serum tears contain key components (i.e., epidermal growth factor, fibronectin, vitamin A) that support epithelial proliferation, maturation, and migration; and hence wound healing. However, autologous serum is contraindicated in cases of herpetic eye disease. Therefore, over-the-counter preservative-free artificial tears are indicated when the cause of the neuropathy is unclear.

P= Partial Tarsorrhaphy For neurotrophic ulcers in patients who have normal lid position and apposition, a temporary partial lateral tarsorrhaphy can help reduce tear film evaporation while still allowing for drop instillation. While suturing is an option, there are some advantages to doing it yourself using the latest-generation cyanoacrylate tissue adhesives (i.e., Super Glue or Dermabond) including:

• Availability
• Nontoxic to skin
• Can be done in the outpatient clinic
• Inexpensive
• Painless
• Usually lasts for weeks and is repeatable when necessary

While a common side effect is the temporary loss of eyelashes, most patients prefer this approach when compared to the more invasive suture tarsorrhaphy.

However, for paralytic lid lag (i.e., trigeminal nerve damage), consider a surgical consultation. Procedures designed to narrow the palpebral fissure (i.e., tarrsorhaphy, lower-lid spacers, medial canthoplasty) and/or improve amplitude of the blink reflex (i.e., gold weight or spring implant) can be very helpful in relieving symptoms and preventing epithelial breakdown.

E = Eliminate Offending Agents With neurotrophic eye disease, it is important to think “addition by subtraction” when trying to improve the health of the ocular surface. From a topical standpoint, it is reasonable to decrease or eliminate (when possible) any topical medications that could be the source of the problem or that may be adversely affecting your efforts. Switching to preservative-free compounds is certainly an excellent start, but we must be mindful that even certain preservative-free compounds may have active ingredients that are pro-inflammatory (i.e., Zioptan [Merck]). Other examples of addition by subtraction include:

• Stopping Viroptic (Pfizer) in favor of an oral antiviral such as Famvir (Novartis) or acyclovir.
• Stopping a topical aminoglycoside in favor of a fluoroquinolone, which be may less toxic while offering a broader spectrum of antibacterial activity.
• Switching from generic brimonidine preserved with BAK to Alphagan 0.1% (Allergan) preserved with Prurite.

We must also re-evaluate the need for certain systemic drugs that may hinder tear production or a patient's blink reflex (i.e., antihistamines, antipsychotics, and neuroleptics). CLS

For references, please visit www.clspectrum.com/references.asp and click on document #203.