Fast versus gradual adaptation of soft daily disposable contact lenses in neophyte wearers.

PURPOSE: Despite the widespread practice of gradually adapting all new soft contact lens wearers (neophytes), there is little evidence-based research underpinning such practice. This work determined if a gradual adaptation period is necessary for neophytes when fitted with modern hydrogel or silicone-hydrogel daily disposable contact lenses. METHOD: At four sites, neophytes (19-32 years) were randomly assigned to an adaptation schedule: fast (10 h wear from the first day) or gradual (4 h on the first day, increasing their wear-time by 2 h on each subsequent day until they had reached 10 h) with hydrogel (n = 24 fast; n = 21 gradual) or silicone-hydrogel (n = 10 fast; n = 10 gradual) contact lenses. Masked investigators graded ocular surface physiology and non-invasive tear breakup time (NIBUT). A range of subjective scores (using 0-100 visual analogue scales) were recorded at the initial visit and after 10 h of lens wear, 4-6 days and 12-14 days after initial fitting. Subjective scores were also repeated after 7 days. RESULTS: There was no difference (p > 0.05) in ocular surface physiology between the fast and gradual adaptation groups at any time point in either lens type. NIBUT was similar at all time points for both adaptation groups in both lens types with the exception that the gradual adaptation silicone-hydrogel wearers had a slightly longer NIBUT (p = 0.007) than the fast adaptation group at 12-14 days. Subjective scores were also similar across the visits and lens types with the exception of 'lens awareness' and 'ease of lens removal' which were better (p < 0.05) in the fast compared with the gradual adaptation hydrogel lens group at day 7. Additionally, 'end-of-day discomfort' was better (p = 0.02) in the fast compared with the gradual adaptation hydrogel lens group at 12-14 days. CONCLUSION: There appears to be no benefit in daily disposable soft contact lens adaptation for neophytes with modern contact lens materials.

Strip meniscometry tube: a rapid method for assessing aqueous deficient dry eye.

BACKGROUND: The aim of this study was to investigate the utility of strip meniscometry tube (SMTube) for the quantitative assessment of the tear film, by comparing it to measurements of tear turnover rate using the gold standard method, fluorophotometry. Also, to determine the viability of this test as a diagnostic tool for aqueous deficient dry eye (ADDE), to inform appropriate clinical management. METHODS: Thirty-two participants (15 ADDE; 17 non-ADDE) were recruited. Tear turnover rate of the right eye of each subject was conducted with an automated scanning fluorophotometer and SMTube test was conducted. Tear meniscus height was assessed using a slitlamp biomicroscope and eyepiece graticule. RESULTS: Significant differences between the ADDE and the non-ADDE groups were found for all measures: tear turnover rate 7.9 ± 1.8 versus 19.6 ± 5.9 per cent/minute (p < 0.001), SMTube 3.2 ± 1.1 versus 5.7 ± 2.3 mm (p = 0.001) and tear meniscus height 0.18 ± 0.05 versus 0.23 ± 0.04 mm (p = 0.004). Moreover, significant correlations were found between tear turnover rate and SMTube (rho = 0.78, p < 0.001), tear turnover rate and tear meniscus height (rho = 0.54, p < 0.001) and SMTube and tear meniscus height (rho = 0.47, p < 0.01). Using a receiver operating characteristic curve, SMTube showed a sensitivity of 67 per cent and a specificity of 88 per cent for the diagnosis of ADDE. CONCLUSION: Given its performance, availability, speed and the fact it is relatively cheap, the study shows that the SMTube can be used as an alternative to fluorophotometry to assess tear production. It appears from the results that SMTube is a viable minimally invasive test for the diagnosis of ADDE.

Safety of buccal infiltration local anaesthesia for dental procedures.

AIM: To assess the safety of buccal infiltration local anaesthetic (LA) without additional factor replacement in patients with haemophilia (PWH) and association with clinical experience of the operator. METHODS: A consecutive sample of participants with mild, moderate and severe haemophilia scheduled to have dental treatment were recruited from a comprehensive care centre in Ireland. Infiltration LA was administered using a standard technique. Safety was defined as any adverse event at time of administration, immediate postoperative, or postoperative period. Clinical experience was dichotomized into fewer or greater than three years clinical experience. RESULTS: N = 135 buccal infiltration LAs without additional factor replacement were provided to N = 71 participants with mild (n = 20; 28%) and moderate to severe haemophilia (n = 51; 72%). Successful local anaesthesia was achieved in n = 133 cases (99%). No (0%) adverse bleeding events were recorded for any participants at time of administration of LA or during follow-up. Three out of 135 (2.2%) LAs recorded superficial bleeding 30 seconds after administration of LA, all of which resolved within 2 minutes with application of pressure; 4 out of 135 (3%) LAs produced a superficial haematoma at the site of injection no greater than 2 mm all of which resolved at 4 minutes. There were no differences in bleeding rates between clinicians by level of experience (P = 0.435) or by severity of bleeding disorder (P = 1.0). CONCLUSION: Local anaesthetic is safe to administer via buccal infiltration for people with mild, moderate and severe haemophilia without additional factor cover. This finding holds true regardless of operator experience.

Effect of humidity variations in a controlled environment chamber on tear evaporation after dry eye therapy.

PURPOSE: Many dry eye (DE) patients are sensitive to adverse environments where tear evaporation rate (TER) increases. Pilot study-A controlled environment chamber was used to determine the time of exposure required for TER to reach steady state equilibrium at 40% relative humidity (RH). Study 1-To assess the difference between normal and DE subjects in their tear physiology response. Study 2-To determine, under varying environmental conditions, the efficacy of an emulsion eye drop on tear physiology. METHODS: Pilot study-TER adaptation time was determined by exposing 3 normal and 3 DE subjects to RH of 40% at 72°F for 0, 5, 10, 15, 20, and 25 minutes. Study 1-The difference in noninvasive tear breakup time (NITBUT) and TER responses between DE and normal subjects were determined at various RH from 5% to 70% (at 72°F) for 20 subjects (10 normal subjects; 10 DE subjects). Study 2-To assess the efficacy of an emulsion eye drop, the same 20 subjects were dosed four times per day for 7 days with a drop containing emulsified castor oil and reassessed. RESULTS: Pilot study-Evaporation at 40% RH showed a peak (around 5 minutes) followed by a decline to steady state level at 10 minutes. Dry eye subjects showed greater evaporation than normal subjects at 40% and 5% RH but not at 70%, where TER declined to zero in both groups. No significant change in NITBUT was found in either group for the various exposure times of the test period (P>0.05). Study 1-TER was higher in DE compared with normal subjects at 5% or 40% RH, however reduced to almost zero in both groups at 70% RH. A significant difference in NITBUT was found between the DE and normal groups at each humidity (P<0.05). Study 2-An emulsion-based drop effectively lowered the TER, especially in DE patients. For NITBUT, a significant improvement in both normal and DE subjects was found at 5% and 40% but not at 70% RH levels. CONCLUSIONS: Pilot study-TER measurements required at least 10 minutes in the chamber to obtain a steady-state TER with no significant change to NITBUT. Study 1-TER has a reverse correlation with environmental humidity in the range of 5% to 70%, with TER reduced to zero at 70% RH. Dry eye subjects had a higher TER at all RH levels below 70%, and NITBUT is significantly different between DE and normal subjects at all humidities. Study 2-Emulsion-based drops reduced TER in DE patients by an amount equivalent to that obtained by raising environmental humidity by 30%. Noninvasive tear breakup time was improved in both normal and DE subjects at lower RH levels.

Effectiveness of dry eye therapy under conditions of environmental stress.

PURPOSE: Dry eye is often characterized by increased tear evaporation due to poor tear film quality, especially of the lipid component of the tear film. Using an environmental chamber to induce environmental stress, this study compared the effect of three lubricant eye drops on various aspects of tear physiology in a crossover design (evaporation was the principal outcome measure). METHODS: Three eye drop formulas were tested: 0.5% carmellose sodium (Drop C), 0.5% carmellose sodium with added lipid (Drop C-L) and 1.0% glycerine with added lipid (Drop G-L). Nineteen control and 18 dry eye subjects used each product for 2 weeks, three times per day, in a random order, with a minimum 1-week washout between treatment periods. Tear evaporation, break up time, osmolarity, tear structure (by interferometry) and patient symptoms were assessed with the subjects adapted for 10 min in an environmental chamber controlled at 20% relative humidity and 22 °C. The treatment effects were analyzed using general linear model repeated measures analyses of variance. RESULTS: In dry eye subjects, evaporation, break up time, osmolarity and symptoms improved for all formulas (p < 0.05). Normal subjects showed some improvements: evaporation with C-L, osmolarity with C and symptoms with C-L and G-L. Change in evaporation was greater for both C-L and G-L versus C (p < 0.05), and there was a trend for C-L to reduce evaporation more than G-L (p < 0.11). There were no significant treatment effects on tear film structure. CONCLUSION: Overall, the eye drop formula containing both carmellose sodium and lipid (C-L) produced a greater treatment effect on tear evaporation than the other formulations containing only one of these ingredients. This study also demonstrates the utility of a controlled environmental chamber in showing the difference in performance between dry eye treatments.