School of Optometry and Vision Science, Level 3, North Wing, Rupert Myers Building, Gate 14, Barker Street, The University of New South Wales, UNSW Sydney, NSW 2052, Australia.
Exp Eye Res. 2011 May;92(5):408-13. doi: 10.1016/j.exer.2011.02.016. Epub 2011 Mar 3.
Assessment of corneal sensory function is commonly carried out using the Cochet-Bonnet aesthesiometer. The limitations of this instrument have lead to development of newer instruments, such as the CRCERT-Belmonte aesthesiometer, which utilise a jet of air as their stimulus. Recent work, however, has demonstrated contradictory effects on ocular surface sensitivity when measured with different types of aesthesiometer. The purpose of the present study was to compare clinical measurements of corneal sensitivity obtained with the CRCERT-Belmonte and the Cochet-Bonnet aesthesiometers and to examine their stimulus characteristics in terms of force exerted. No association was found between central corneal sensitivity measured with the two aesthesiometers in a group of normal subjects. Sensitivity was measured to be lower with the Cochet-Bonnet aesthesiometer than with the CRCERT-Belmonte. Over half of the subjects could not be assessed with the standard Cochet-Bonnet filament and 11% could not be assessed with either filament, as their corneal sensitivity was outside of the range of the instrument. In contrast, all subjects were within the stimulus range of the CRCERT-Belmonte aesthesiometer. Corneal sensitivity measurements made with the non-contact CRCERT-Belmonte aesthesiometer and the Cochet-Bonnet aesthesiometer are not comparable. Due to dissimilarities in the composition of their stimuli, and thus mode of stimulation, it is possible that the two instruments measure different aspects of the neural response. The underestimation of corneal sensitivity by the Cochet-Bonnet aesthesiometer and its inability to measure sensitivity of some subjects at all are important considerations in the assessment of sensitivity loss. Subtle changes are unlikely to be detected with this instrument, particularly at higher sensitivity levels. The Cochet-Bonnet should therefore be used with caution and the 0.08 mm diameter used as the filament of choice. Adoption of a non-contact aesthesiometer as standard for ocular sensitivity measurement should be considered. The non-contact instrument allows superior stimulus reproducibility and better control over stimulus characteristics, in addition to the ability for exploration of the response of all three types of neuro-receptors on the ocular surface.
角膜感觉功能评估通常使用科赫特-邦尼特触觉计进行。该仪器的局限性导致了新型仪器的开发，例如 CRCERT-Belmonte 触觉计，它使用空气喷射作为刺激源。然而，最近的研究表明，使用不同类型的触觉计测量时，对眼表面敏感性的影响是矛盾的。本研究的目的是比较 CRCERT-Belmonte 和科赫特-邦尼特触觉计测量的角膜敏感性的临床测量，并检查它们在力施加方面的刺激特性。在一组正常受试者中，未发现两种触觉计测量的中央角膜敏感性之间存在关联。与 CRCERT-Belmonte 相比，科赫特-邦尼特触觉计测量的敏感性较低。超过一半的受试者无法使用标准科赫特-邦尼特细丝进行评估，11%的受试者也无法使用任何一种细丝进行评估，因为他们的角膜敏感性超出了仪器的范围。相比之下，所有受试者都在 CRCERT-Belmonte 触觉计的刺激范围内。使用非接触式 CRCERT-Belmonte 触觉计和科赫特-邦尼特触觉计进行的角膜敏感性测量无法进行比较。由于它们的刺激物组成不同，因此刺激方式也不同，这两种仪器可能测量的是神经反应的不同方面。科赫特-邦尼特触觉计低估了角膜敏感性，而且根本无法测量某些受试者的敏感性，这在评估敏感性丧失时是需要考虑的重要因素。使用该仪器不太可能检测到细微的变化，尤其是在较高的敏感性水平。因此，应谨慎使用科赫特-邦尼特触觉计，并选择 0.08 毫米直径的细丝作为首选。应考虑采用非接触式触觉计作为眼部敏感性测量的标准。非接触式仪器除了能够探索眼表面三种神经感受器的反应外，还允许更好的刺激重现性和对刺激特性的更好控制。
