Could contact lens dryness discomfort symptoms sometimes have a neuropathic basis?

Abstract

Symptoms of dryness discomfort in soft contact lens wearers frequently lead to discontinuation from wear. The negative influence of pre-fitting tear dysfunctions appears likely to be exacerbated by the challenges to tear homeostasis caused by contact lenses. The corneal mechanisms for symptoms in contact lens wearers are different to those for dry eye disease because the cornea is insulated by the lens from ambient conditions as well as from lid wiper friction during blinking. Symptoms of dryness discomfort might be the consequence of increased lid wiper friction during blinking when the lens front surface becomes soiled and dry and exhibits very rapid tear break up. It is possible that some cases of contact lens intolerance and discontinuation could be a function of lid wiper neuropathy. In relation to the possibility of corneal neuropathy, a stagnant post-lens tear pool with the possibility of increased concentrations of metabolic by-products, cellular debris, and bacterial exotoxins, might have the potential to disturb the corneal epithelial and sub-basal nerves. Contributions by contact lens-induced inflammation to any neuropathic changes may partly depend on the degree to which inflammatory mediators are concentrated in a stagnant post-lens tear pool. It does not appear to be known if corneal neuropathic changes could develop under these conditions. The chances of neuropathic involvement may be greater if discomfort develops after a significant period of successful wear and there is a history of comorbid pain conditions. Esthesiometry and in vivo confocal microscopy in discontinued contact lens wearers may support a diagnosis of contact lens-related corneal neuralgia.

Influence of Selected Ophthalmic Fluids on the Wettability and Hydration of Hydrogel and Silicone Hydrogel Contact Lenses—In Vitro Study

“…Some studies show that dry eye symptoms can be better characterized as neuropathic eye pain [11,12]. According to McMonnies [12], some cases of contact lens intolerance may be due to eyelid wiper neuropathy.…”

“…Some studies show that dry eye symptoms can be better characterized as neuropathic eye pain [11,12]. According to McMonnies [12], some cases of contact lens intolerance may be due to eyelid wiper neuropathy. A stagnant post-lens tear pool with the possible increased concentrations of metabolic by-products, cellular debris, and bacterial exotoxins can disrupt the corneal epithelial and sub-basal nerves.…”

Pre-Lens Tear Meniscus Height, Lipid Layer Pattern and Non-Invasive Break-Up Time Short-Term Changes with a Water Gradient Silicone Hydrogel Contact Lens

“…In recent years, soft contact lenses (SCLs), and particularly silicone hydrogels (SHs), have experienced constant changes by the specialized industry, promoting the development of materials, designs and treatments with greater biocompatibility with human tissue, which provide better properties for corneal physiology, eye comfort and wettability [1][2][3][4]. Despite the introduction of new materials and surfactants in contact lens design [5,6], SH-SCL users continue to report dryness and eye discomfort at some time in the day [7], representing one of the main causes of leaving CLs [8]. Crucial comfort factors could be related to changes generated by interactions of the tear film within ocular tissues [9].…”

Corneal neuropathic pain: a review to inform clinical practice

“…Questionnaires have also been used to assess diseases associated with CNP. For example, contact lens wear maybe a cause of CNP with symptoms of dryness, grittiness, scratchiness and foreign body sensation being identified on questionnaires [44] such as the contact lens dry eye questionnaire and contact lens discomfort index [45][46][47] (Table 1). In terms of systemic diseases, validated questionnaires such as the Liverpool Sicca index, EULAR Sjogren's Syndrome Patient Reported Index and Sicca Symptoms Inventory have also been used to evaluate patients with primary Sjogren's syndrome and include ocular symptoms such as dryness, irritation and poor vision [48][49][50] (Table 1).…”