Severe symptoms of short tear break-up time dry eye are associated with accommodative microfluctuations

Minako Kaido,^1,2 Motoko Kawashima,¹ Reiko Ishida,^1,3 Kazuo Tsubota<sup>1

1</sup>Department of Ophthalmology, Keio University School of Medicine, Tokyo, ²Wada Eye Clinic, Chiba, ³Ishida Eye Clinic, Shizuoka, Japan

Aim: Validating the hypothesis that accommodative microfluctuations (AMFs) may be associated with severe symptoms in short tear break-up time (BUT) dry eye (DE).
Methods: This study included 12 subjects with short BUT DE (age: 49.6±18.3 years). Diagnoses were performed based on the presence of DE symptoms, BUT ≤5 s, Schirmer score >5 mm, and negative keratoconjunctival epithelial damage. Tear evaluation, AMF, and functional visual acuity (VA) examinations were conducted before and after DE treatment. The AMF parameters evaluated were: total high-frequency component (HFC), HFC with low accommodation for the task of staring into the distance (HFC1), HFC with high accommodation for deskwork (HFC2). A subjective questionnaire of DE symptoms was also performed.
Results: Mean BUT increased from 1.9±2.0 to 6.4±2.5 s after treatment (P<0.05). The mean logarithm of the minimum angle of resolution functional VA significantly improved (from 0.19±0.19 to 0.12±0.17; P<0.05). Mean power spectrum values for total HFC and HFC1 decreased (from 61.3±5.7 to 53.8±6.6 dB and from 62.9±10.5 to 52.4±6.2 dB, respectively; P<0.05), while the mean HFC2 power spectrum values did not differ before and after treatment (P>0.05). Subjective DE symptoms were reduced in nine patients.
Conclusion: Along with the improvement of BUT after treatment, DE symptoms diminished and HFC1 and functional VA improved, suggesting that tear film instability is associated with deterioration of functional VA, AMF, and DE symptoms.

Keywords: accommodative microfluctuation, ciliary muscle spasm, dry eye, ocular fatigue, tear break-up time, functional visual acuity