Article

CLINICAL: CORNEA

GUIDE YOUR WAY THROUGH SPK

Identify and alleviate the cause of superficial punctate keratopathy

Superficial punctate keratopathy (SPK) appears as irregularities in the squamous epithelium of the cornea that stain with NaFl or Rose Bengal. The staining can range from individual, tiny dots located diffusely over the surface of the cornea to more confluent arrangements of staining in specific patterns. The doctor can determine the cause of SPK based on its appearance and location. Determining the cause is essential for prescribing the most effective treatment.

Here, I discuss the signs of SPK, their related diagnoses and how to best treat them as a result. (A caveat: This summary is in no way exhaustive. For example, SPK can lead to disease deeper in the corneal epithelium or stroma, but I do not review those cases here.)

SUPERIOR SPK

  • Contact lens related. Poorly fitting contact lenses or protein deposits on contact lenses and resultant giant papillary conjunctivitis (GPC) can often cause SPK to appear at the superior 1/3 of the cornea. The finding of large papillae associated with GPC under the upper lid or heavy depositing of the contact lens can lead to a definitive diagnosis.
    Have the patient discontinue contact lens wear until the SPK and GPC resolve. Next, consider fitting him in a daily disposable lens, to avoid depositing and GPC associated with longer wear contact lenses.
  • Superior limbic keratitis. SPK near the superior limbus along with staining of superior bulbar and tarsal conjunctiva is indicative of superior limbic keratitis. Suspicion for superior limbic keratitis should be heightened in females in their 50s.
    There is no gold-standard treatment for this condition, however, symptoms may lessen using some combination of topical steroids, NSAIDs, bandage contact lenses, artificial tears and cyclosporine.
ICD 10
Unspecified superficial keratitis H16.10
Unspecified corneal ulcer H16.00
Punctate keratitits H16.14
Keratoconjunctivitis (not specified as Sjogren’s) H16.22

INFERIOR

  • Lagophthalmos. Inferior, diffuse band-shaped SPK that stains with NaFl is associated with an incomplete blink leaving the inferior portion of the cornea exposed.
    Prescribe this patient a viscous artificial tear to be used at bedtime when you suspect nocturnal lagophthalmos. Some patients fare well with sleep masks or taping their lid when a gel tear does not resolve their symptoms. Additionally, consider other dry eye disease treatments. Their use is relative to the patient’s symptoms and clinical findings.
  • Blepharitis. Inferior diffuse SPK should also lead the clinician to observe the lid margin for signs of MGD, scurf and telangiectasias. As you know, blepharitis treatment can be complex and should be directed toward the cause.
    Along with treating the underlying lid condition, if the patient has acute symptoms, prescribe a combination agent to be used four times a day for three to seven days.
  • Medicamentosa. Prolonged or frequent use of ophthalmic drops that contain preservatives or other irritants can cause fine SPK in the inferior portion of the cornea.
    Ask the patient about OTC and prescription drop use to elicit this history.
    Instruct this patient to discontinue the offending agent temporarily, if he is able to, or consider switching him to a non-preserved alternative, and observe for improvement. Depending on the presenting severity and type of medication use, have the patient return in one to four weeks to look for marked improvement.
  • Trichiasis/entropion. Confluent areas of SPK may be a sign of misdirected, typically from the bottom eyelid. Look closely for misdirected lashes, and epilate the offending lash.

PERIPHERAL

  • Staphylococcus aureas exotoxin reaction/blepharitis. Blepharitis can also cause peripheral confluent or focal areas of SPK near the limbus. Along with treating the underlying lid condition, add a combination antibiotic and steroid to hasten the resolution of acute symptoms.
  • Contact lens related. A contact lens that is too tight, has protein deposits or is over worn can cause peripheral SPK. A tight fit seen via slit lamp and the patient admitting to over wearing or poor care of his contact lenses indicates this diagnosis. Prescribe a contact lens “vacation” until resolved, and consider adding a combination agent to be used four times a day for three to seven days to speed up resolution.
    Finally, counsel the patient on contact lens care and wear times, and consider switching lens modality to a flatter lens or to a daily disposable, depending on the original cause for the contact lens-associated SPK.

INTERPALPEBRAL

  • Dry eye/keratoconjunctivitis sicca. In cases in which NaFl and Rose Bengal stain in a diffuse, band-shaped pattern exposed by the open eyelids, consider a dry eye or keratoconjunctivitis sicca diagnosis. (Editor’s note: See https://bit.ly/2JED7Nz for a review of dry eye treatments.)

Note the band SPK on this dry eye disease patient.
Image courtesy of Dr. Savannah Long

DIFFUSE

  • Medicamentosa. Prolonged or frequent ophthalmic medication use may also cause a diffuse, fine SPK over the entire surface of the cornea. Ask the patient about OTC and prescription drop use. Discontinue the offending agent temporarily if the patient is able to, or consider switching to a non-preserved alternative to observe for improvement.
  • Adenoviral. Early adenoviral keratoconjunctivitis may present with a non-descript, diffuse SPK without the other tell-tale signs of the condition, such as lid edema, chemosis or subepithelial corneal infiltrates. If the patient divulges he has had a recent upper respiratory tract infection or was exposed recently to someone who had pink eye, this is a strong indication you are dealing with this condition. A definitive diagnosis is contingent on the positive results of an in-office test for adenovirus, and the presence of swollen or tender pre-auricular nodes.
    The gold standard for the treatment of viral conjunctivitis is still out for the jury. In our clinic, I suggest artificial tears, topical steroids for infiltrates and, rarely, a betadine rinse in office in hopes to reduce the viral load and shorten the length of the infection.
    A final note: Because of the contagious nature of the condition, caution the patient strongly on hand hygiene, and disinfect the exam room and waiting area with a 1:10 bleach solution or CaviWipes (Metrex) upon his departure.
  • Thygesons. The finding of diffuse confluent grey to white round lesions that stain poorly with NaFl and often have a slightly raised appearance may raise your suspicion for this condition. Thygesons superficial punctate keratitis typically presents with no other conjunctival signs.
    Prescribe this patient topical steroids, topical cyclosporine and preservative-free artificial tears according to symptom severity, until symptoms and signs have resolved.

FOCAL

  • Infectious keratitis. Any focal area of SPK or an epithelial defect overlying an infiltrative lesion, especially in conjunction with purulent discharge, photophobia, anterior chamber reaction and focal stromal edema should be considered highly suspicious of this condition. (Editor’s note: See https://bit.ly/2BrqQrT for review of infectious keratitis.)
  • Recurrent corneal erosion. Focal SPK associated with negative staining and a history of pain upon waking. Prescribe artificial tears, topical steroids and a bandage contact lens to aid in stronger re-epithelialization of the lesion. To prevent re-occurrence, prescribe nightly hypertonic ointment and oral doxycycline 50 mg to 100 mg. The ointment reduces corneal edema, and the oral doxycycline improves lid hygiene and ocular surface inflammation.

A WORK IN PROGRESS

As with any clinical diagnosis in optometry, cases can evolve over the course of a few fol-low-up visits to lead you to the final diagnosis.

In some cases, especially when infection is suspected, laboratory testing, such as corneal or conjunctival swab testing for pathogens, is necessary to confirm the diagnosis.

Occasionally, a patient’s failure to respond to treatment can lead you down a different path altogether. However, initially taking a systematic approach to diagnosing the cause of a patient’s SPK will help get you to the finish line of providing the best care to your patient. OM