Three must-have specialty diagnostic drops every primary care practice should have.
Visualization of clear structures is of the utmost importance in eyecare. Viewing structures a different way helps more efficiently diagnose lid disease and corneal and conjunctival disorders. It even helps when viewing contact lenses. Vital dyes such as sodium fluorescein (NaFL), lissamine green and rose bengal make this task significantly simpler. Here’s more on why you should have this trio in your tray.
The versatility of NaFL is apparent in its extensive applications. NaFL works preferentially on tissues where there is damage, which allows this dye to enter the cell. The dye is most useful aiding in the diagnosis and grading of dry eye disease since tear break-up time can be measured with NaFL. A tear break-up time less than 10 seconds is indicative of dry eye disease.
NaFL’s ability to stain breaks in the corneal epithelium allows us to not only visualize but grade the level of dry eye disease. For instance, according to the Report of the Definition and Classification Subcommittee of the International Dry Eye Workshop, corneal staining more than a mild amount classifies as moderate dry eye.
Corneal staining is also of use when determining corneal abrasions versus an infective etiology. Punctate staining or pooling on the cornea can indicate an abrasion. When the abrasion is larger the area of pooling allows measurement of the defect. Staining over an area where there is an infiltrate is more likely an infective process. All of the above appear as positive staining. Negative staining or areas where NaFL is decreased after application can indicate an uneven cornea. This would include map-dot-fingerprint/epithelial basement membrane dystrophy or Salzmann’s nodules.
Used post surgically, NaFL can be used to paint the wound site to determine the presence of wound leakage. In addition to disease processes, fluorescein sodium is beneficial when viewing rigid contact lenses. It allows the viewing of the tear film underneath the lens to evaluate lens fit.
ROSE BENGAL AND LISSAMINE GREEN
Rose bengal and lissamine green are dyes that work very similarly. Both stain dead and devitalized cells on the conjunctiva and the cornea, and neither can penetrate a healthy mucous layer.
I find rose bengal is easier to visualize on the eye but is more irritating to the patient. This irritation can last up to a day in severe dry eye cases. Rinsing with saline after use can improve this.
Diagnosing herpetic corneal infections is the greatest impact of these two dyes. While NaFL can help in the diagnosis of herpetic infections by staining eroded areas of the dendrites, rose bengal will stain the characteristic epithelial dendrites of herpetic corneal disease. Both dyes will stain the conjunctiva in dry eye disease. The thickened lid margin at the line of Marx will also be stained by these dyes. This can be debrided to help improve evaporative dry eye.
There are certainly other dyes that are more specialized but not used on an almost daily basis. If you are practicing primary eyecare, these dyes are a must. These are the primary specialty dyes that I find myself utilizing most frequently in my practice.
Mark MacMillan, OD, is in private practice in Virginia Beach, VA.
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