Corneal and conjunctival sensitivity in intolerant contact lens wearers / Sensibilidad corneal y conjuntival en pacientes con intolerancia a las lentes de contacto

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IgE antibody on worn highly oxygen-permeable silicone hydrogel contact lenses from patients with contact lens-induced papillary conjunctivitis (CLPC).

PURPOSE: To investigate whether the level of IgE is increased in the eyes of patients during general contact lens-induced papillary conjunctivitis (CLPC) events, which involve enlarged papillae across the entire palpebral conjunctiva, or local CLPC events, in which papillae are confined to one or two parts of the area. METHODS: Worn contact lenses were collected and soaked in phosphate-buffered saline. The levels of eluted IgE and IgE retained on contact lenses were detected by enzyme-linked immunosorbent assay. RESULTS: IgE was detected in 6 of 12 cases of general CLPC, 8 of 21 cases of local CLPC, and none of 14 control contact lenses. The average level of eluted IgE was 0.54 +/- 1.06 IU/contact lens, 0.28 +/- 0.54 IU/contact lens, and 0.04 +/- 0.06 IU/contact lens for general CLPC, local CLPC, and the control group, respectively. The incidences of positive IgE were significantly higher in patients with CLPC (general and local) than in control subjects, but no statistical difference was found between general and local CLPC. Generally higher amounts of retained IgE were detected on contact lenses that had increased levels of eluted IgE. Contact lenses that were collected before or after a CLPC event did not show increased levels of IgE. CONCLUSIONS: The level of IgE is increased in the eyes of some patients during an acute event of CLPC. The similar incidence of IgE-positive cases and levels of IgE from general and local CLPC contact lenses suggest that the conditions may share similar causal pathways.

Performance standards for toric soft contact lenses.

PURPOSE: To simplify the clinical assessment of toric soft contact lens (TSCL) on-eye behavior by establishing a set of standard clinical evaluation techniques. The likely performance range expected among the TSCL wearing population was determined for a series of lens designs and acceptable performance standards indicated for each variable. METHODS: Four prism-ballast, two peri-ballast and one dynamic stabilization TSCL designs were each worn by groups of 20 subjects in a nondispensing study. After 20 min of lens wear, lenses were assessed, in right eyes only, for subjective comfort (100-point scale), lens mislocation (degrees deviation from vertical) and rotational recovery after deliberate 30 degrees mislocation (degrees/10 blinks). The percentage of lenses orienting within +/-10 degrees of target orientation (zero rotation) and the variability of orientation (standard deviation of mislocation) were also calculated for each lens group. RESULTS: Based on partitioning of the data distributions for each variable, performance was designated as excellent, acceptable or poor. Corresponding performance cut-offs were determined at > or =90, 89 to 80, and <80 for subjective comfort, < or =+/-6 degrees , +/-7 degrees to 10 degrees , and >+/-10 degrees for mislocation, >10 degrees /10 blinks, 10 degrees to 6 degrees /10 blinks, and <6 degrees /10 blinks for rotational recovery. For groups of wearers the appropriate cut-offs were > or =90%, 89 to 70%, and <70% of lenses orienting within +/-10 degrees of target orientation and <+/-6 degrees , +/-6 degrees to 10 degrees , and >+/-10 degrees for variability of orientation. CONCLUSION: Techniques suitable for the evaluation of TSCL clinical performance have been described and guidelines for the assessment of such lenses established. In the process, we have identified potential performance differences that may relate to variations in TSCL design.

Silicone hydrogel contact lenses and the ocular surface.

For 30 years, contact lens research focused on the need for highly oxygen-permeable (Dk) soft lens materials. High Dk silicone hydrogel contact lenses, made available in 1999, met this need. The purpose of this review is to examine how silicone hydrogel lens wear affects the ocular surfaces and to highlight areas in which further research is needed to improve biocompatibility. Silicone hydrogel lenses have eliminated lens-induced hypoxia for the majority of wearers and have a less pronounced effect on corneal homeostasis compared to other lens types; however, mechanical interaction with ocular tissue and the effects on tear film structure and physiology are similar to that found with soft lens wear in general. Although the ocular health benefits of silicone hydrogel lenses have increased the length of time lenses can be worn overnight, the risk of infection is similar to that found with other soft lens types, and overnight wear remains a higher risk factor for infection than daily wear, regardless of lens material. Future contact lens research will focus on gaining a better understanding of the way in which contact lenses interact with the corneal surface, upper eyelid, and the tear film, and the lens-related factors contributing to infection and inflammatory responses.

Two presentations of contact lens-induced papillary conjunctivitis (CLPC) in hydrogel lens wear: local and general.

PURPOSE: The purpose of this study was to confirm that two distinct clinical presentations of contact lens-induced papillary conjunctivitis (CLPC), local and general, occur in hydrogel lens wear. METHODS: Retrospective analyses of 124 CLPC events were identified. The classification of CLPC was based on location and extent of papillae. CLPC was classified as local if papillae were present in one to two areas of the tarsal conjunctiva and general if papillae occurred in three or more areas. The CLPC events were compared with an asymptomatic control group in prospective clinical trials conducted from 1993 until 2003 at two clinical sites, Australia and India. Two hundred sixteen subjects from Australia and 914 subjects from India wore either high Dk silicone hydrogel or low Dk hydrogel lenses on a 6-night (6N) or 30-night extended-wear (EW) schedule. The physiological responses of the ocular surface, including tarsal conjunctiva redness and roughness, number of papillae present, lens fit and performance, and subjective patient symptoms, were measured during each visit at each site. These variables listed were compared between local CLPC groups and asymptomatic controls and general CLPC groups and asymptomatic controls. RESULTS: Two types of CLPC in hydrogel lens wearers have been confirmed. Of the 124 CLPC events, there were 61 local and 63 general events. Local and general CLPC cases reported significantly greater frequency of symptoms compared with the asymptomatic controls, in particular itching, lens awareness, secretion, and blurred vision (p < 0.1). CONCLUSIONS: The classification of CLPC into two types, local and general, in hydrogel lens wear was confirmed based on presentations at both sites. This distribution of papillae between local and general CLPC may indicate separate etiologies involved in the pathogenesis of the condition.

Case reports of three atypical infiltrative keratitis events with high DK soft contact lens wear.

PURPOSE: We report three atypical infiltrative keratitis events in patients that had successfully worn highly oxygen permeable (Dk) soft contact lenses on an extended wear (EW) schedule for at least 15 months. These cases highlight the role of patient/practitioner education, patient compliance, examination, and appropriate referrals that are required to reduce the risk of complications during lens wear. METHODS AND RESULTS: Each patient had been wearing high Dk soft lenses on an EW schedule with monthly replacement for at least 15 months and presented with severe pain, redness, and photophobia. The events were characterized by focal infiltrate(s) with an overlying epithelial defect in the superior periphery to mid-periphery of the cornea and extensive diffuse infiltration. CONCLUSIONS: The signs and symptoms of each case were more severe than is typically associated with contact lens-related infiltrative keratitis. Because of the slow progression of signs and relatively fast resolution, the cases were not found to be microbial keratitis. Although high Dk soft contact lenses overcome hypoxia-associated complications associated with extended wear, patients and practitioners must be vigilant as adverse events can still occur and in rare instances can be severe. Education and patient compliance are a crucial part of successful management of patients on EW schedules. Constant reinforcement is necessary to ensure patient compliance.