Juana Gallar,1* Celia Morales,2 Vanesa Freire,2 M. Carmen Acosta,1 Carlos Belmonte,1 and Juan Antonio Duran3
1Instituto de Neurociencias, Universidad Miguel Hernandez-CSIC, San Juan de Alicante, Spain
2Instituto Clinico Quirurgico de Oftalmologia, Bilbao, Spain
3Ophthalmology, Universidad del Pais Vasco, Leioa, Spain; Instituto Clinico Quirurgico de Oftalmologia, Bilbao, Spain
To investigate corneal sensitivity to selective mechanical, chemical, heat, and cold stimulation in fibromyalgia (FM) patients.
Twenty FM patients (18 female, 2 male; 51,9±2,3 years old) and 18 control subjects (16 female, 2 male; 51,7±2,4 years) participated voluntarily in the study. Subjective symptoms of ocular dryness were explored and Schirmer's1 test was performed. The response to selective stimulation of the central cornea with the Belmonte gas esthesiometer was measured.
The majority (18 out of 20) of FM patients reported dry eye symptoms, being the ocular dryness score significantly higher than in healthy subjects (2,3±0,1 vs. 0,05±0,02; p<0,001). Schirmer's test values were significantly reduced in FM patients compared to those of the control group (10,5±,2 mm and 30,6±1,6 mm, respectively; p<0,001). Mean corneal threshold sensitivity to chemical stimulation (31,16±2,04 % CO2 FM; 15,72±0,67% CO2 control) to heating (1,87±0,11 °C FM; 0,99±0,05 °C control) and to cooling (-2,53±0,11 °C FM; -0,76±0,05 °C control) were increased in FM patients while threshold to mechanical stimulation did not vary significantly (123,0±8,0 ml/min FM; 107,8±4,4 ml/min control).
The reduced corneal sensitivity of patients with fibromyalgia is attributable to a moderate decrease of corneal polymodal and cold nociceptor sensitivity, that may be the consequence or the cause of the chronic reduction in tear secretion also observed in these patients.
The Association for Research in Vision and Ophthalmology, Inc. DOI: 10.1167/iovs.08-3083