Lissamine green, an eye-drop stain used by ophthalmologists to detect damaged cells on the eye's surface, can reveal staining patterns that are key to diagnosing dry eye syndrome earlier than other methods, confirms a new study at the University of Texas Southwestern Medical Center.
The new findings suggest that the eye-staining technique can provide doctors with more options for treating the potentially sight-stealing disease.
"What this research showed is that the degree and pattern of staining was a good, objective indicator of the severity of the tear deficiency," said Dr. James McCulley, chairman of ophthalmology at UT Southwestern.
In a study, published in the journal Eye and Contact Lens, the researcher found that the severity of the dry eye condition in patients correlates with where the stain patterns show up, and identified three basic patterns that indicated progressively dangerous conditions.
The least-severe condition is indicated by stains limited to the whites of the eyes between the lids toward the nose. It might be caused by environmental factors like pollution, and does nto necessarily predict dry eye.
The second level appears as stains in the white of the eye between the lids, but toward the ear. "That is fairly diagnostic of a tear deficiency," said Dr. McCulley, the study's senior author. The third and most severe level occurs when the stain also appears on the cornea.
"That's when things really get serious. If the dry eye is significantly affecting the cornea, it deteriorates vision and adds a major risk factor for a person developing a bad infection," said Dr. McCulley.
The researchers examined the stain patterns in 22 patients with varying degrees of dry eyes and 11 patients without ocular disease, who served as control subjects. They found that lissamine green strain was more beneficial over the more commonly used fluorescein stain, which does not easily identify damage until it is more progressed.
"If an ophthalmologist uses the most commonly used stain, which is fluorescein, they're going to miss the first two stages of the development of dry eye and consequently miss a lot of diagnoses," said Dr. McCulley.
Earlier diagnosis is crucial in giving doctors more treatment options and preventing the disease from getting worse. Dry eye syndrome can also signal other conditions such as lupus or rheumatoid arthritis, further underscoring the importance of early diagnosis.
"The more severe stage is not only more problematic in affecting vision, but it is more difficult to treat and reverse. So it's very important to diagnose at the mild stages because it can become a self perpetuating disease if not effectively treated," Dr. McCulley said.