Evaluation of dry eye subtypes and characteristics using conventional assessments and dynamic tear interferometry.

ABSTRACT

BACKGROUND/AIMS: To evaluate subtypes and characteristics of dry eye (DE) using conventional tests and dynamic tear interferometry, and to investigate determinants of disease severity in each DE subtype. METHODS: 309 patients diagnosed with DE and 69 healthy controls were prospectively enrolled. All eyes were evaluated using Ocular Surface Disease Index (OSDI), Schirmer's test I (ST1) and Meibomian gland dysfunction (MGD) grade were analysed. The tear interferometric pattern and lipid layer thickness were determined using DR-1α and LipiView II, respectively. RESULTS: Dynamic interferometric analysis revealed 56.6% of patients with DE exhibited Jupiter patterns, indicative of aqueous-deficiency, while 43.4% exhibited crystal patterns, indicative of lipid deficiency. These findings were in accordance with classification based on ST1 scores and MGD grade. Conventional assessment indicated 286 patients exhibited evidence of evaporative DE (EDE) due to MGD, while only 11 exhibited signs of pure aqueous-deficient DE (pure ADDE, only ST1 ≤5 mm). Interestingly, of 286 patients with EDE, 144 were categorised into the mixed-ADDE/EDE group, in which ST1 was identified as a strong negative determinant of OSDI. In contrast, 72.2% of patients with mixed-ADDE/EDE exhibited Jupiter patterns (Jupiter mixed), while 27.8% exhibited crystal patterns (crystal mixed). OSDI values were significantly higher in the crystal-mixed group than in the Jupiter mixed, in which OSDI scores were independently associated with ST1 values only. CONCLUSIONS: Our findings indicate that majority of EDE patients also exhibit aqueous deficiency, which can aggravate symptoms even in patients with lipid-deficient mixed-ADDE/EDE. Conventional assessments should be combined with interferometric tear analysis to determine the most appropriate treatment for each DE patient.