To define a combination between Schirmer I and phenol red thread test (PRT) that improves the screening of patients with ocular sicca syndrome.
Materiels and methods:
The PRT test was performed before (PRT1) and after (PRT2) the Schirmer I test, in both eyes of 143 patients complaining of ocular dryness secondary to Sjögren's syndrome (SS) or Sicca Asthenia Polyalgia Syndrome (SAPS) (72 and 71 patients respectively), and in 40 control patients. Groups were matched by age and gender. After determining the best cut-off values using the ROC (Receiver Operating Characteristic) procedure, several combinations of PRT and Schirmer I were assessed to improve the predictive values of the procedure.
The best cut-off value for PRT2, estimated at 15mm, provided a satisfying match between sensitivity and specificity indexes (68% and 90% respectively), similar to those obtained with the Schirmer I test. If PRT1 alone was ineffective to screen SGS from control patients, the comparison between PRT 1 and PRT2 (so-called "delta-PRT") was found as a good marker to detect patients with persistent tear reflex. Interestingly, the combination of positive Schirmer I, PRT 2 and/or delta-PRT tests was found as highly predictive of severe ocular sicca syndrome.
The combination of Schirmer I and PRT test strongly improves the screening procedure to detect patients with ocular dryness related to Sjögren or SAPS syndrome. It could be more widely used in daily clinical practice, besides Schirmer I test, to optimize the work-up of patients presenting with dry-eye subjective signs.
Invest Ophthalmol Vis Sci. 2011 May 5. [Epub ahead of print]
De Monchy I, Gendron G, Miceli C, Pogorzalek N, Mariette X, Labetoulle M.
Ophthalmology Department Hôpital de Bicêtre, Assistance Publique-Hôpitaux de Paris, 94275 Le Kremlin-Bicêtre Cedex, FRANCE.