Nerves and Sensations from the Eye Surface

Belmonte, Carlos; Aracil, Adolfo; Acosta, M. Carmen; Luna, Carolina; Gallar, Juana

doi:10.1016/s1542-0124(12)70112-x

Cited by 180 publications

(169 citation statements)

References 30 publications

Supporting

Mentioning

159

Contrasting

Unclassified

Order By: Relevance

“…In our experiment, mean sensitivities in both groups were about the same as those previously reported on non-lens-wearing normal subjects. 30,34 This suggests that in this sample of silicone hydrogel and daily disposable lenses wearers there was no obvious sensitivity decrease compared with the conventional soft and hard contact lens wearers, 35,36 perhaps partially because of the higher oxygen permeability of the new materials. 15,36 Belmonte et al 37,38 proposed that the occurrence of symptoms was through the activation of sensory nerves innervating the ocular surface when the eye lid slid over the dry ocular surface.…”

Section: Discussionmentioning

confidence: 78%

“…However, Belmonte et al 35,44 speculated that subtle injury of corneal nerve endings in lens wearers was similar to damaged corneal neurons after laser-assisted in situ keratomileusis surgery and photorefractive keratectomy 45 and that the regenerated nociceptors had increased spontaneous activity as well as longer lasting after-discharges in response to suprathreshold stimulation. We hypothesized that this altered neural functioning that was the basis of hyposensitivity, and hyperalgesia experienced by subjects after laser refractive surgery 44,46 perhaps was implicated in the etiology of reported discomfort in contact lens-wearing patients reporting dry eyes.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

A Role of Corneal Mechanical Adaptation in Contact Lens–Related Dry Eye Symptoms

Chen

Simpson

2011

Invest. Ophthalmol. Vis. Sci.

View full text Add to dashboard Cite

PURPOSE.To compare corneal mechanical adaptation measured psychophysically in contact lens wearers with or without dry eye symptoms. METHODS. Two groups of contact lens wearers were recruited. One group (symptomatic) consisted of subjects with dry eye symptoms (according to the subjective evaluation of symptom of dryness [SeSoD] questionnaire). The second control group (asymptomatic) consisted of subjects reporting no symptoms. There were 32 (aged 20 to 42 years, 6 males and 26 females) and 29 subjects (aged 21 to 36 years, 9 males and 20 females) in the symptomatic and asymptomatic groups, respectively. Mechanical stimulus thresholds of the cornea were determined using a Belmonte pneumatic esthesiometer and the ascending method of limits. Then three stimulus intensity groups (subthreshold, threshold, and suprathreshold) were applied to the eye in random order, each 20 times. Subjects rated the intensity of the stimuli using a scale of zero to four. The rating data from the two groups were compared by Friedman nonparametric ANOVA. Adaptation was defined as the reduction in subsequent ratings compared with earlier ones. RESULTS. No significant difference was seen in subjects' thresholds in both groups (P ϭ 0.22). The symptomatic group rated their sensations to suprathreshold stimuli higher than the asymptomatic group. More importantly, there was significant adaptation with suprathreshold mechanical stimulation in the asymptomatic group (P ϭ 0.006) but not in the symptomatic group (P ϭ 0.08). There was no adaptation during threshold and subthreshold stimulus sessions in either group. CONCLUSIONS. Adaptation was found to suprathreshold mechanical stimuli in the asymptomatic group but not in the symptomatic group. (Invest Ophthalmol Vis Sci. 2011;52: 1200 -1205) DOI:10.1167/iovs.10-5349 C ontact lens-related dry eye symptoms have received attention from both clinicians and researchers. It was reported in an examination of optometric practices that half of contact lens wearers (50.1%) had dry eye symptoms, whereas much fewer than half of the number of non-lens wearers reported symptoms (21.7%).1 Dry eye symptoms have been reported to be a major reason for the discontinuation of contact lens wear.2,3 Because of the distinct pattern of contact lens-related dry eye, as well as the different sex and age prevalence in non-lens wearers, 4 the mechanisms of contact lens-related dry eye could be different from that of non-contact lens-related dry eye. 5,6Factors related to lens wear comfort may include the geometry of the lens (particularly thickness and edge design), environmental conditions (temperature and humidity), tear film structure, corneal physiology, and factors affecting ocular surface neural activity.7 Recently adopted daily disposable lenses have decreased the effect of deposits on the lenses, and so chronic lens deposition itself is perhaps of less etiologic importance in contact lens-related discomfort.8 Hypoxia is a factor that has been suggested to be closely related to contact lens comfort, 9 -11 and numer...

show abstract

Section: Discussionmentioning

confidence: 78%

Section: Discussionmentioning

confidence: 99%

A Role of Corneal Mechanical Adaptation in Contact Lens–Related Dry Eye Symptoms

Chen

Simpson

2011

Invest. Ophthalmol. Vis. Sci.

View full text Add to dashboard Cite

show abstract

“…La forte densité des terminaisons nociceptives de la cornée (7 000 nocicepteurs par mm 2 ) est une de ses caractéristiques [5]. L'épithélium cornéen compte 500 fois plus de terminaisons libres nerveuses que le derme et 30 fois plus que la pulpe dentaire [6]. L'innervation cornéenne joue un rôle trophique pour la cornée mais assure aussi la détection des stimulus extérieurs (comme la température, la pression mécanique, etc.)…”

Section: Innervation Cornéenne : Anatomie Et Physiologieunclassified

“…Il est nécessaire de distinguer la douleur oculaire physiologique nociceptive de la douleur oculaire neuropathique [3,37]. En effet, la prise en 6 Filaments de nylon d'égale longueur, mais variant en diamètre, qui permettent d'appliquer sur la zone de choix, à la main, une force reproductible. À chaque filament est assignée une valeur en mg.…”

Section: éValuation De La Douleur Oculaireunclassified

La douleur oculaire chronique : mieux la comprendre pour mieux la traiter

Goazigo¹,

Labbé²,

Baudouin³

et al. 2017

Med Sci (Paris)

View full text Add to dashboard Cite

> La sècheresse oculaire est un des premiers motifs de consultation en ophtalmologie. Sa prévalence varie de 5 à 35 % chez des sujets âgés de plus de 50 ans. Cette pathologie du segment antérieur de l'oeil est caractérisée par des sensations de douleur variables dans leurs intensités, allant du simple inconfort à une douleur oculaire prononcée. Les douleurs oculaires sont très invalidantes et très difficiles à traiter, et leurs mécanismes physiopathologiques demeurent mal connus de nos jours. Ce constat impose un approfondissement de nos connaissances fondamentales sur l'anatomie du système nociceptif cornéen et sur les mécanismes cellulaires impliqués dans l'initiation et la chronicisation de la douleur oculaire. Cette revue présente, dans une première partie, l'anatomie de l'innervation cornéenne et les différentes classes de récepteurs sensitifs cornéens. La seconde partie fait un état des lieux des données précliniques et cliniques portant sur les mécanismes inflammatoires mis en jeu dans cette pathologie. Enfin la dernière partie de cette revue décrit les différents dispositifs actuellement utilisés pour évaluer la douleur et l'inflammation oculaire en clinique humaine. < sulaire présent ou potentiel, ou décrite en terme d'un tel dommage ». Les pathologies de la surface oculaire représentent l'un des principaux motifs de consultation pour douleurs oculaires en ophtalmologie. La douleur oculaire est le plus important signe cardinal d'alerte en réaction à une inflammation ou à un traumatisme des structures du segment antérieur de l'oeil comme la cornée, la conjonctive, la sclère 2 et les structures uvéales. La douleur oculaire chronique est tout à fait remarquable par la variabilité de l'intensité qu'elle peut générer, allant du simple inconfort oculaire à une douleur intense voire insupportable. La douleur chronique consé-cutive à une pathologie de la surface oculaire affecte la qualité de la vie : près de 60 % des patients se déclarent gênés dans leurs activités quotidiennes [1]. En outre, 80 % des patients qui souffrent de douleur oculaire ne l'estiment pas suffisamment prise en considération tant par leur entourage que par leurs médecins. Les douleurs chroniques oculaires sont malheureusement parmi les plus difficiles à traiter et leurs mécanismes physiopathologiques, de nature neurogène et/ou inflammatoire, demeurent de nos jours très mal connus [2,3]. Innervation cornéenne : anatomie et physiologieLa sensibilité somatique de la face, incluant les cavités buccale et nasales, et des méninges, est assurée par les trois branches du ganglion trigéminal : ophtalmique (V1), maxillaire (V2) et mandibulaire (V3). Le nerf ophtalmique V1 se divise en trois branches sensitives : les 2 Enveloppe fibreuse externe du globe oculaire.

show abstract

“…17,18 Trigeminal ganglion sensory neurons innervating the cornea are functionally heterogeneous and have been classified as polymodal nociceptor, mechano-nociceptor, and cold thermoreceptor neurons, on the basis of intensity and form of energy (mechanical, thermal, chemical) that activates preferentially their peripheral corneal terminals. 19,20 Each functional class of corneal neuron evokes qualitatively distinct conscious sensations 21,22 and contributes differently to the modulation of tearing and blinking. 20,23,24 Experimental evidence suggests that mechano-nociceptors are important in evoking acute pricking pain when the cornea is mechanically stimulated, while activation of polymodal nociceptors by mechanical, thermal, or chemical noxious stimuli evokes burning pain, hyperalgesia, and neurogenic inflammation.…”

mentioning

confidence: 99%

Functional and Morphologic Alterations in Mechanical, Polymodal, and Cold Sensory Nerve Fibers of the Cornea Following Photorefractive Keratectomy

Bech

González-González

Artime

et al. 2018

Invest. Ophthalmol. Vis. Sci.

Self Cite

View full text Add to dashboard Cite

PURPOSE. To define the characteristics and time course of the morphologic and functional changes experienced by corneal sensory nerves after photorefractive keratectomy (PRK).METHODS. Unilateral corneal excimer laser photoablation was performed in 54 anesthetized 3-to 6-month-old mice; 11 naïve animals served as control. Mice were killed 0, 3, 7, 15, and 30 days after PRK. Excised eyes were placed in a recording chamber superfused at 348C. Electrical nerve impulse activity of single sensory terminals was recorded with a micropipette applied onto the corneal surface. Spontaneous and stimulus-evoked (cold, heat, mechanical, and chemical stimuli) nerve terminal impulse (NTI) activity was analyzed. Corneas were fixed and stained with anti-b-Tubulin III antibody to measure nerve density and number of epithelial nerve penetration points of regenerating subbasal leashes.RESULTS. Nerve fibers and NTI activity were absent in the injured area between 0 and 7 days after PRK, when sparse regenerating nerve sprouts appear. On day 15, subbasal nerve density reached half the control value and abnormally responding cold-sensitive terminals were recorded inside the lesion. Thirty days after PRK, nerve density was almost restored, active cold thermoreceptors were abundant, and polymodal nociceptor activity first reappeared.CONCLUSIONS. Morphologic regeneration of subbasal corneal nerves started shortly after PRK ablation and was substantially completed 30 days later. Functional recovery appears faster in cold terminals than polymodal terminals, possibly reflecting an incomplete damage of the more extensively branched cold-sensitive axon terminals. Evolution of postsurgical discomfort sensations quality may be associated with the variable regeneration pattern of each fiber type.

show abstract

Nerves and Sensations from the Eye Surface

Cited by 180 publications

References 30 publications

A Role of Corneal Mechanical Adaptation in Contact Lens–Related Dry Eye Symptoms

A Role of Corneal Mechanical Adaptation in Contact Lens–Related Dry Eye Symptoms

La douleur oculaire chronique : mieux la comprendre pour mieux la traiter

Functional and Morphologic Alterations in Mechanical, Polymodal, and Cold Sensory Nerve Fibers of the Cornea Following Photorefractive Keratectomy

Contact Info

Product

Resources

About

Nerves and Sensations from the Eye Surface

Cited by 180 publications

References 30 publications

A Role of Corneal Mechanical Adaptation in Contact Lens–Related Dry Eye Symptoms

A Role of Corneal Mechanical Adaptation in Contact Lens–Related Dry Eye Symptoms

La douleur oculaire chronique : mieux la comprendre pour mieux la traiter

Functional and Morphologic Alterations in Mechanical, Polymodal, and Cold Sensory Nerve Fibers of the Cornea Following Photorefractive Keratectomy

Contact Info

Product

Resources

About

La douleur oculaire chronique : mieux la comprendre pour mieux la traiter