Contact Lens Insertion Research Articles

YouTube as a learning source for contact lens insertion and removal

ABSTRACT Clinical relevance Contact lens neophytes often learn about contact lens insertion and removal through YouTube videos of unknown quality. Background This study evaluates the quality of soft contact lens insertion and removal videos on YouTube. Methods A search for the keywords ‘Contact lens insertion’, ‘Contact lens removal’, ‘Put in contact lens’, and ‘Take off contact lens’ was performed on YouTube. The first 50 videos for each keyword were evaluated. The number of views, source of the publisher, days since upload, and video quality were scored based on the content in the videos. The maximum score of insertion and removal videos were 7 and 5 respectively. The videos were classified into three groups by publisher category: videos published by eye care professionals, companies and YouTubers. Results Only 45 contact lens insertion and 44 removal videos met the inclusion criteria and were analysed. Insertion and removal videos published by YouTubers had the highest view and view rate. However, their quality scores were significantly lower than videos published by eye care professionals and companies. Videos uploaded by companies had the highest scores (insertion: 5.00 ± 1.10; removal: 3.25 ± 0.75). The mean scores of insertion and removal videos published by YouTubers were 1.65 ± 0.93 and 1.00 ± 0.89, respectively, while the insertion and removal videos uploaded by eye care professionals scored 3.58 ± 2.07 and 2.75 ± 1.53, respectively. There was also a negative correlation between the quality scores and view rate (p = 0.008, r = -0.41). Conclusion Contact lens insertion and removal videos uploaded by YouTubers had the highest view rate but the lowest quality. Videos made by companies included most essential elements.

Assessment of condition-induced changes on the ocular surface using novel methods to assess the tear film dynamics and the lipid layer

ObjectivesTo assess the effects of different condition-induced changes on current and novel ocular surface metrics. MethodsEighty-four healthy volunteers (22.4 ± 2.6 years) participated in this study. The ocular surface and tear film response to (1) computer use, (2) contact lens insertion and (3) tear film instillation during computer use with contact lenses were assessed. Current metrics included the ocular surface disease (OSDI) questionnaire, 5-item dry eye questionnaire (DEQ-5), bulbar redness, tear meniscus height (TMH) and non-invasive keratograph break-up time (NIKBUT). Novel metrics included the lipid layer thickness obtained from the intensity of the reflected Placido disk and the speed of tear film particles post-blink. ResultsHigher dry eye symptoms, TMH and bulbar redness, and lower values in metrics related to the intensity of the Placido disk pattern and to particle speed were found after the computer reading task (p < 0.036). When a contact lens was fitted, lower TMH, NIKBUT and particle speed metrics were obtained (p < 0.044). Mixed ANOVA revealed that artificial tears significantly ameliorated the effect of computer reading on OSDI, DEQ-5, NIKBUT, metrics related to the intensity of the Placido disk pattern and metrics related to particle speed (p < 0.033). ConclusionsComputer use and contact lens wear worsened dry eye signs and symptoms, but artificial tears ameliorated this effect. Newly developed methods can serve as a tool to detect changes in the tear film triggered by different ocular surface-disturbing conditions.

Stabilization of comfort and visual quality after the insertion of soft contact lenses

PurposeTo evaluate comfort, visual function, and in vivo wettability after the insertion of hydrogel and silicone hydrogel contact lenses for a better understanding of how long practitioners should wait for the initial evaluation of soft contact lenses. MethodsA short-term prospective, contralateral, randomized, and participant-masked study was carried out. Twenty healthy participants (25.4 ± 2.6 years) were evaluated after the insertion of two different soft contact lenses at different times (1, 5, 10, 20, 30 min). Ocufilcon D (hydrogel) and Somofilcon A (silicone hydrogel) contact lenses were randomly assigned to both eyes of the same participant. Comfort, visual function under photopic conditions in terms of high-contrast visual acuity, low-contrast visual acuity, contrast sensitivity, and in vivo wettability were measured. ResultsThere was an increase in comfort (p < 0.001), high-contrast visual acuity (p < 0.05), and contrast sensitivity (p < 0.001, only with silicone hydrogel) directly related to time after contact lens insertion. Besides, in vivo wettability suffered a statistically significant deterioration directly related to time with both contact lenses (p < 0.05). Except for comfort and contrast sensitivity, all the parameters stabilized their values 10 min after the insertion of both soft contact lenses. Additionally, in vivo wettability and visual acuity differences were found between hydrogel and silicone hydrogel contact lenses (p < 0.05). ConclusionsIt would be possible to properly evaluate high-contrast visual acuity, low-contrast visual acuity, and in vivo wettability 10 min after the insertion of both soft contact lenses.

Contact lens procurement and usage habits among adults in Sudan.

The study aimed to assess contact lens (CL) wear and care habits among adults in Sudan. An observational, non-interventional, multi-center, cross-sectional study was conducted in the CL departments of all the eye hospitals and centers, and optical centers in the Khartoum State, Sudan. Established CL wearers residing in Khartoum State, Sudan. CL wear profile, CL usage habits, hand and CL hygiene habits were assessed using an interviewer-administered questionnaire. The average age of the 442 participants was 24.57 (± 4.87) years. Women comprised 92% of the sample. Smoking was reported by 15.8% of the sample. 81.9% wore soft spherical CL, with 43.4% of the participants were prescribed CL on a yearly replacement schedule. Only 68.3% were prescribed CL by an eye care practitioner. Multipurpose solutions were used by 78.8% of the sample to clean CL, and by 52% to clean the lens case. Compliance rate for CL wear and care among participants was 81.1%. None of the participants reported sharing CL or CL case and rinsing the case with tap water. High compliance level was observed for overnight wear; swimming and showering with CL; handwashing before CL insertion; and cleaning of CL. Moderate compliance rates were recorded for cleaning and replacing lens case, and topping up or sharing solution. Low compliance was noted for attending after care visits. CL wearers in Sudan exhibit high to moderate levels of compliance to most contact lens wear and care aspects, except for attending aftercare visits. CL practitioners in Sudan are encouraged to prescribe CL appropriate to the lifestyle and economic situation of patients and actively recommend care products. In addition, practitioners need to follow up with patients to attend aftercare appointments, where hygienic wear and care habits should be emphasized.

Evaluation of the Quality, Reliability, and Educational Content of YouTube Videos as an Information Source for Soft Contact Lenses.

To evaluate the quality, reliability, and educational content of YouTube videos related to soft contact lenses (CL). An online YouTube search was performed for the terms contact lens and other common CL-related terms contact lens insertion and removal, contact lens wearing, and contact lens care. The first 50 videos were evaluated for each term. Videos were evaluated using three checklists (the modified DISCERN criteria, the Journal of the American Medical Association [JAMA] criteria, and Global Quality Score [GQS]). Video popularity was also evaluated using the video power index (VPI). Videos were classified into three groups according to the source of the upload; group 1: universities/occupational organizations, group 2: medical ad/profit-oriented companies, and group 3: independent users. From among the 200 videos analyzed, 79 were included. The mean mDISCERN score of the videos was 2.34±1.39, the mean JAMA score was 1.20±0.99, and the mean GQS value was 3.47±1.28. There were positive correlations between the three checklists (P<0.001). Video power index was not correlated with each score. The videos in group 1 (13.9%) had the highest scores whereas videos in group 3 (41.8%) had the lowest scores. There was no significant difference between the video sources according to the VPI. Although some YouTube videos contain useful information for CL wearers, most videos have poor quality and reliability and contain insufficient information. Eye care providers should be aware of these sources and steer CL users to information sources that provide accurate and reliable information and do not contain misleading information.

Tear film stability over a myopia control contact lens compared to a monofocal design

ABSTRACT Clinical relevance: Tear film assessment is essential in contact lens wearers and it can improve the success rates of the fitting. Background: To compare the short-term effect of two contact lenses on pre-lens tear film stability and comfort: dual-focus contact lens (MiSight) and a monofocal contact lens (Proclear 1-day). Methods: This randomised, double-masked, crossover study was performed in twenty-eight healthy, myopic volunteers aged between 18 and 32 years (23.5 ± 4.1 years). Only one randomly chosen eye was assessed. Distance vision and refraction were evaluated at baseline. Each contact lens type (monofocal and dual-focus) was randomly fitted, always in both eyes. A visual analogue scale between 0 and 10 was used to assess general comfort, physical comfort, and visual comfort. Tear Film Surface Quality (TFSQ) index, TFSQ_area and auto Tear Break-Up Time were obtained using Medmont E-300 at baseline (naked eye condition) and 25 minutes after each contact lens insertion. Results: Refractive sphere and cylinder were, respectively, −1.36 ± 1.04 D (ranging from −6.00 to −0.25 D) and −0.23 ± 0.30 D (ranging from −0.75 to 0.00 D). TFSQ and TFSQ area were lower (meaning more stable tear film) at baseline when compared with both contact lens types (p < 0.025). Higher pre-lens tear instability (larger TFSQ and_TFSQ area values) was found with the dual-focus than the monofocal lens. Auto Tear Break-Up Time was higher at baseline than with each of the contact lenses, without statistically significant differences between both contact lens types. Visual analogue scales revealed statistically significant better scores in the monofocal contact lens than in dual-focus contact lens for general (0.77 ± 1.14 vs 3.12 ± 2.79), physical (0.96 ± 1.46 vs 2.19 ± 2.45) and visual comfort (1.27 ± 1.66 vs 3.92 ± 2.04). Conclusion: A slight reduction in short-term pre-lens tear film stability was found in the dual-focus design in comparison with the monofocal lens, potentially contributing to the deterioration of visual performance and comfort during dual-focus contact lens wear.

Cyanoacrylate tissue adhesive for the management of corneal perforation in dogs:a report of three cases

Corneal perforation can cause profound vision loss and requires immediate treatment. Bandage contact lens insertion and gluing are temporary treatment methods. However, if the patient cannot undergo surgery for a variety of reasons, these methods are inevitably used as permanent treatment methods. The use of cyanoacrylate tissue adhesive (CTA) for the management of corneal perforation in humans has been reported for several decades. Here we describe, for the first time as per our knowledge, the use of CTA (Vetbond) for the management of corneal perforation with a diameter of

Comparison of the impact of nesofilcon A hydrogel contact lens on the ocular surface and the comfort of presbyopic and non-presbyopic wearers.

To assess and compare the impact of a daily disposable contact lens (CL) with high water content on the ocular surface and comfort of the presbyopic and non-presbyopic population after one day of use. Totally 20 presbyopes and 30 non-presbyopes non-contact wearers were fitted with nesofilcon A CLs. CL thickness was measured to assess material stability during daily wear, and ocular surface parameters were also assessed. Optical quality was analyzed for all cases. In addition, CL comfort was rated. No significant differences were found in CL thickness, tear film osmolarity, average tear break-up time, bulbar redness, central corneal thickness, corneal volume, root-mean-square of higher-order aberrations (RMS of HOAs) and vertical and horizontal coma, either as a function of the group or time of use. A significant decrease in tear meniscus height and first break-up of the tear film was found in the presbyopic group (P=0.038; P=0.007 respectively). A decrease in spherical aberration coefficient was found after CL insertion (P=0.031 monofocal CL; P=0.023 low addition multifocal CL; P=0.016 high addition multifocal CL). Multifocal CL were thicker than monofocal CL (P=0.045). Comparison between groups showed more discomfort in presbyopes than non-presbyopes (P=0.003). This study evidence that the behavior of the daily disposable CL with high water content seems to be stable during the day of use. Ocular parameters measured during wear show that CL behavior is the same for presbyopes and non-presbyopes, being more uncomfortable for presbyopes.

Eye rubbing type and prevalence including contact lens ‘removal‐relief’ rubbing

BackgroundEye rubbing is commonly associated with keratoconus and may contribute to disease onset and progression. Verbal counselling to avoid rubbing may not be successful and adverse consequences of rubbing, which occurs on contact lens removal may be more serious. This study examines the prevalence of ‘removal‐relief’ rubbing and its potential consequences.MethodsRubbing histories were recorded for contact lens wearing normal and keratoconic patients as well as for normal non‐contact lens wearers. Analogue scaled responses were used to identify and compare abnormal rubbing habits.ResultsContact lens wearing patients (both with and without keratoconus) reported significantly more rubbing before contact lens insertion (p < 0.05) compared to non‐contact lens wearers. Eye rubbing after contact lens removal (‘removal‐relief’ rubbing) was found to be significantly more prevalent among contact lens‐wearing keratoconic patients compared to contact lens‐wearing non‐keratoconic patients (p < 0.001 in both cases).ConclusionsRubbing‐related trauma occurring before contact lens insertion may predispose the cornea to wound healing activities and greater levels of adverse response to contact lens wear. Such adverse responses could predispose the cornea to greater trauma, which occurs in response to rubbing on removal of contact lenses. Strong counselling to avoid eye rubbing is often not an adequate form of management for a significant number of patients with keratoconus. Evidence of relapses indicates the need for better methods of counselling and for them to be repeated regularly. Apart from keratoconus, any other keratectasia, corneal disease or wound healing (including post‐surgical) may increase susceptibility to corneal rubbing trauma. Such cases also appear to warrant counselling on avoidance of rubbing.

Clinical outcomes of xeno-free expansion and transplantation of autologous ocular surface epithelial stem cells via contact lens delivery: a prospective case series

IntroductionDepletion of limbal stem cells leads to a debilitating condition known as limbal stem cell deficiency, characterised by impaired corneal wound healing and poor vision. The aim of this study was to determine whether delivering progenitor cells on a contact lens is a viable and effective alternative to current transplantation techniques, which are complicated by biological and xenogeneic materials.MethodsSixteen eyes of 16 patients who had total (n = 14) and partial (n = 2) limbal stem cell deficiency (chemical burns, five eyes; iatrogenic causes, four eyes; aniridia, three eyes; trachoma-induced, two eyes; contact lens over-wear, one eye; and cicatrising conjunctivitis, one eye) and who had failed prior therapy were recruited prospectively into the study. Autologous limbal (n = 7) or conjunctival epithelial (n = 9) biopsies were harvested from patients and placed on the concave surface of silicone hydrogel contact lenses. Cells were expanded in culture with autologous serum and transplanted onto the ocular surface.ResultsRestoration of a transparent avascular and clinically stable corneal epithelium was attained in 10 of 16 eyes (63%) at a median follow-up time of 2.5 years (range of 0.8 to 5.8 years). Although minor complications occurred in two eyes of two patients because of contact lens insertion or removal, these were not associated with long-term sequelae.ConclusionsThis is the first and largest study to evaluate the mid-term outcomes of autologous limbal/conjunctival stem cell transplantation via a US Food and Drug Administration-approved contact lens, demonstrating that delivery of ocular progenitor cells via this procedure offers a viable, effective, and xeno-free alternative to current transplantation methodologies.Trial registrationAustralian New Zealand Clinical Trials Registry ACTRN012607000211460. Registered 17 April 2007.

The Impact of Written Information on the Compliance with Contact Lens Care

Purpose: To evaluate the impact of written information on the compliance with proper contact lens (CL) care. Methods: The patients prescribed CLs by a single ophthalmologist in a clinic from January 2008 to August 2009 were enrolled in the present study. The patients were randomly divided into 2 groups, the verbal and written information (VWI) group and verbal information (VI) group. The patients in the VWI group received verbal and written information on proper CL care and the VI group received the same information only verbally. Patients who were followed-up more than 2 weeks after CL wear were asked 10 questions regarding CL care and statistical analysis was performed for each question on CL care. The Mann Whitney U-test was used for comparison between the 2 groups and Pearson’s test was used for the correlation analyses. Results: A total of 23 patients were included in this study. Ten patients were assigned to the VWI group, and 13 patients to the VI group. The most desirable score for the CL care was 100 points. The VWI group showed 85.2 ± 13.4 points and the VI group showed 71.5 ± 10.1 points (p = 0.030, Mann-Whitney U-test). Of the 10 questions, daily replacement of the lens care solution and the use of tap water showed significant correlation with the discomfort induced by the CL and rinsing process before CL insertion showed significant correlation with the CL intolerance (p = 0.008, p = 0.004 and p = 0.015, respectively, Pearson’s correlation test). Conclusions: The patients in the written information group showed better compliance for overall CL care. Adding the written information to the verbal explanation can enhance the patient’s compliance with the proper CL care. Enhancing the compliance of CL care with written information can be expected to decrease the complications and improve the comfort of wearing CLs. J Korean Ophthalmol Soc 2015;56(12):1848-1853

Lower tear meniscus in computer reading task with and without soft contact lens

Dry eye is the major contributor to computer vision syndrome. The reductions in the blink rate and amplitude have been considered as the possible mechanisms leading to this condition. The purpose of this study is to evaluate the changes in the lower tear meniscus heights and areas in the computer reading task, in dry eye subjects, with and without soft contact lenses. In this quasi-experimental study , 39 subjects (with mean age of 21.2 ± 2.4 years), with dry eye, were enrolled. The lower tear meniscus height and area (TMH, TMA) of the right eye was captured by Spectral Optical Coherence Tomography before and after 45 minutes of reading task behind desktop 17” Cathode Ray Tube monitors. The same procedure was performed after the insertion of the hydrogel soft contact lenses with 58% water content. The results of TMHs, TMAs were analyzed with a repeated measures analysis of variance (ANOVA) with two within-subject factors. : The mean ± standard error of TMH and TMA pre and post computer tasks were 283.6± 25.4 µm, 0.029±0.005 mm2, 297.6±20.7 µm , 0.036 ± 0.005 mm2 respectively. After contact lens insertion, the mean TMH and TMA pre and post computer task were 231.6 ± 10.6 µm, 0.020±0.0019 mm2, 213.0±9.0 µm, 0.018 ± 0.0011 mm2, respectively. Repeated measures analysis of variance showed that the changes in TMH (P=0.86) and TMA (P=0.37) after computer task, were not statistically significant, while the insertion of the soft contact lens had reduced the TMH and TMA significantly (P<0.001 for both). After 45 minutes of reading task behind desktop monitors, the tear volume has not changed, with and without high water SCLs. A reduction in tear volume might be expected with longer duration of computer task or at late hours of the day. The creation of a more stable tear film should be considered in the management strategies for shorter duration of work behind desktop monitors.

A randomized clinical comparison of OPTI-FREE EXPRESS and ReNu MultiPLUS multipurpose lens care solutions

To evaluate subjective symptoms and clinical signs of tolerability and comfort in silicone and non-silicone hydrogel contact lens (CL) wearers using two different multipurpose solution (MPS) CL care regimens. This was a randomized, double-masked, contralateral, crossover, multicenter (n=9) study. One hundred and eleven subjects were enrolled in the study, and were randomly assigned either silicone hydrogel CLs or non-silicone hydrogel CLs. Before wear, the CLs were randomly conditioned for at least 10 hours in a multipurpose disinfection solution (MPDS) preserved with either: Regimen 1-polyquaternium-1 0.001% and myristamidopropyl dimethylamine 0.0005% (POLYQUAD and ALDOX, respectively; OPTIFREE EXPRESS MPDS, Alcon Laboratories, Inc., Fort Worth, TX, USA); or Regimen 2-multipurpose solution preserved with polyhexamethylene biguanide 0.0001% (PHMB, ReNu MultiPLUS MPS, Bausch & Lomb, Rochester, NY, USA). The study had two in-office visits, 1 week apart. Subjects wore assigned CLs for approximately 4 hours at each visit. At each visit, subjects' eyes were examined before CL insertion and at 2 hours and 4 hours after insertion. Corneal staining type and area, conjunctival staining, conjunctival injection, subjective symptoms (tolerability), and comfort were evaluated. One hundred and five subjects (210 eyes) completed the study. The total corneal staining score of area and type were statistically significantly less in Regimen 1 than in Regimen 2 (P<0.000001). The area of conjunctival staining was statistically significantly less in Regimen 1 than in Regimen 2 (P=0.03). No clinically significant hyperemia was observed for either regimen. Both tolerability (P=0.02) and patient preference (P=0.05) were in favor of Regimen 1. Statistically significant clinical differences were evident between the two CL care regimens when used with silicone and non-silicone hydrogel CLs. OPTI-FREE EXPRESS MPDS users showed less corneal and conjunctival staining and reported greater comfort and tolerability to the CL/solution combination than ReNu MultiPLUS MPS users.

The Advanced Human Eye Model (AHEM): A Personal Binocular Eye Modeling System Inclusive of Refraction, Diffraction, and Scatter

To present a commercially available software tool for creating eye models to assist the development of ophthalmic optics and instrumentation, simulate ailments or surgery-induced changes, explore vision research questions, and provide assistance to clinicians in planning treatment or analyzing clinical outcomes. A commercially available eye modeling system was developed, the Advanced Human Eye Model (AHEM). Two mainstream optical software engines, ZEMAX (ZEMAX Development Corp) and ASAP (Breault Research Organization), were used to construct a similar software eye model and compared. The method of using the AHEM is described and various eye modeling scenarios are created. These scenarios consist of retinal imaging of targets and sources; optimization capability; spectacles, contact lens, and intraocular lens insertion and correction; Zernike surface deformation on the cornea; cataract simulation and scattering; a gradient index lens; a binocular mode; a retinal implant; system import/export; and ray path exploration. Similarity of the two different optical software engines showed validity to the mechanism of the AHEM. Metrics and graphical data are generated from the various modeling scenarios particular to their input specifications. The AHEM is a user-friendly commercially available software tool from Breault Research Organization, which can assist the design of ophthalmic optics and instrumentation, simulate ailments or refractive surgery-induced changes, answer vision research questions, or assist clinicians in planning treatment or analyzing clinical outcomes.

Evaluating Patient Anxiety Levels During Contact Lens Fitting

Patient anxiety has been shown to be detrimental to many aspects of primary healthcare consultations. However, to date, the subject has received minimal attention within optometric practice. Therefore, the purpose of this study was to evaluate patient anxiety during a commonly conducted type of optometric examination, namely a contact lens fit. Forty participants (15 male, 25 female; mean age 28.3 +/- 9.5) underwent a full contact lens fitting consultation. Skin conductance was recorded continuously to measure participant arousal; the physiological correlate of anxiety. A short form of the Speilberger state anxiety scale was also completed by participants before and after the contact lens fit. Skin conductance analysis identified arousal levels peak during history and symptoms, contact lens insertion and removal and practitioner advice. The Wilcoxen test identified a significant reduction in participant anxiety measured with the shortened Speilberger state anxiety scale after the consultation. Patient arousal levels fluctuate in a characteristic way throughout the contact lens fitting examination. Peak arousal levels occur during periods of 'communicative interaction' between the patient and the optometrist. Since anxiety is associated with poor attention, this suggests that optometrists should not assume that patients remember what they are told during the consultation. Furthermore, patient anxiety is significantly reduced after the examination, which may indicate that patient anxiety is moderated by experience.

Acute angle closure after implantable contact lens insertion unresponsive to surgical peripheral iridectomy

We present a case of acute angle closure that occurred after insertion of an implantable contact lens (ICL). The apparent papillary-block angle closure did not resolve after 2 patent iridotomies and a surgical iridectomy, but did respond to pupil dilation (not constriction). Ultrasound biomicroscopy revealed abnormally large and irregular ciliary processes that may have contributed to the unusual behavior of the ICL-iris complex. The condition resolved after the ICL was replaced by one with a smaller haptic diameter. Routine ultrasound biomicroscopic assessment of the ciliary body anatomy preoperatively and ICL haptic positioning postoperatively may identify risk factors that could predispose ICL patients to acute angle closure.

Contact Lenses in Pediatrics (CLIP) Study: Chair Time and Ocular Health

Despite several studies that show 8- to 11-year-old children are capable of wearing a various contact lens modalities, parents often report that their eye care practitioner would not fit their child with contact lenses until the child was about 13 years old. We conducted the Contact Lenses in Pediatrics (CLIP) Study to compare contact lens fitting and follow-up between 8- to 12-year-old children and 13- to 17-year-old teenagers. At the baseline visit, all subjects underwent a contact lens fitting, including visual acuity, a manifest refraction, autorefraction, and biomicroscopy. Subjects then underwent contact lens insertion and removal training, which consisted of talking about contact lens care as well as inserting and removing a contact lens three times. Subjects returned for follow-up visits at 1 week, 1 month, and 3 months, and visual acuity, contact lens fit assessment, and biomicroscopy were performed. The time of the fitting, the insertion and removal training, and each follow-up visit were measured individually and added for a total chair time. Biomicroscopy examinations were conducted according to a standardized protocol. We enrolled 84 children and 85 teens in the study. Of the 169 subjects, 93 (55.0%) were female, 78 (46.2%) were white, 44 (23.3%) were Hispanic, and 28 (17.6%) were black. The mean (+/- SD) total chair time for children was 110.6 +/- 39.2 min, significantly more than 95.3 +/- 25.2 min for teens (Student's t-test, p = 0.003). Most of the difference was caused by insertion and removal training, which lasted 41.9 +/- 32.0 min for children and 30.3 +/- 20.2 min for teens (Student's t-test, p = 0.01). The presence of conjunctival staining increased from 7.1% of the subjects at baseline to 19.9% of the subjects at 3 months (chi2, p = 0.0006), but the changes were similar between children and teens. No other biomicroscopy signs increased significantly over the 3-month period. The total chair time for children is approximately 15 min longer than teens, but most of that difference is explained by longer time spent teaching children insertion and removal. Because insertion and removal is generally taught by staff members, the eye care practitioner's time with the patient is similar between children and teens. Furthermore, neither children nor teens experienced problems related to contact lens wear during the study. Eye care practitioners should consider routinely offering contact lenses as a treatment option, even for children 8 years old.

Goldmann applanation tonometry over daily disposable contact lens: Accuracy and safety of procedure

Purpose To study accuracy and safety, related to sensation (discomfort) and trauma, when using Goldmann applanation tonometry (GAT) on eyes wearing daily disposable soft contact lenses. Methods The intra-ocular pressure (IOP) of 136 normal eyes of 68 subjects was measured by Goldmann tonometer. Measurements were made in one eye with a contact lens (hilafilcon A) without anaesthetic drops and then without the contact lens using one drop of 0.4% oxybuprocaine hydrochloride. Each contact lens used was identical as to back optic zone, back vertex power. Standard Goldmann procedure only was used for the fellow eye of each subject. Subjective sensation (discomfort) responses to both procedures were studied in a subgroup (66 eyes) using a scale of discomfort, from 1 (no sensation) to 5 (highest sensation). Epithelial staining after tonometry was evaluated for this subgroup. Results No significant differences were found for the IOP with and without contact lens ( t < 1; p = 0.63) for the IOP range studied. There was a good correlation between the two procedures ( r = 0.81; p < 0.05). Lowest sensation was found with tonometry on the anaesthetized cornea; this condition was significantly different from other conditions ( p < 0.005). No difference was found among the other conditions (contact lens insertion, tonometry on contact lens and application of topical anaesthetic). Corneal epithelial staining following the standard tonometry procedure was significantly higher than following the procedure with a contact lens ( p < 0.00005). Conclusions Measurement of IOP by GAT over a daily disposable soft contact lens is accurate, compared to the standard procedure and within the IOP's normal range studied here. Also using a contact lens results in less trauma whilst discomfort is similar.

Double-masked study of the effects of nepafenac 0.1% and ketorolac 0.4% on corneal epithelial wound healing and pain after photorefractive keratectomy

Two NSAIDs--nepafenac 0.1% and ketorolac tromethamine 0.4%-were compared in terms of their effects on corneal reepithelialization and pain after photorefractive keratectomy (PRK) in a randomized, double-masked, contralateral eye, multicenter study. A total of 40 healthy adult patients who were undergoing sequential bilateral PRK received nepafenac 0.1% and ketorolac 0.4% in contralateral eyes, 1 drop 3 times daily for 3 d after bandage contact lens insertion. Patients were assessed on postoperative days 1, 3, 4, 5, and 7. At each visit, patients provided a general rating of pain. Each patient also assessed the sensation of each eyedrop following instillation (after-drop pain, irritation, burning/stinging, and overall comfort). Starting on day 3, epithelial defect size was assessed. Mean epithelial defect size was similar between treatments at each postoperative visit (P>.05). The average time-to-healing was 4.18 d for nepafenac 0.1% and 4.00 d for ketorolac 0.4% (P=.3134). No statistical difference was observed between nepafenac 0.1% and ketorolac 0.4% in mean postoperative pain scores (P>.05). On day 3, the nepafenac 0.1% group had significantly lower mean sensation scores than did the ketorolac 0.4% group for after-drop pain (P=.0090), irritation (P=.0007), and burning/ stinging (P=.0003). Mean overall comfort score was also significantly better for nepafenac 0.1% on day 3 (7.43 vs 6.41; P<.0001). Nepafenac 0.1% and ketorolac 0.4% provide postoperative pain relief after PRK surgery without associated adverse effects on corneal epithelial healing. Nepafenac 0.1% treatment may offer greater comfort upon instillation in patients who have undergone PRK.

Variations in the corneal surface temperature with contact lens wear

This paper presents the two-dimensional simulation of heat propagation in the human eye model during contact lens wear with finite element analysis. Three types of contact lens are studied: Lotrafilcon A, Balafilcon A, and Etafilcon A. The models are solved for both steady and transient solutions. The corneal surface temperature during contact lens wear is found to decrease (average, 0.52 +/- 0.05 degrees C compared with a bare cornea for all lens types). A contact lens with a higher water content has a lower steady state temperature than a contact lens with a lower water content does. Various initial temperatures for the contact lens are found to affect the first 400 s of the temperature variation. When the initial temperature is lower than the corneal temperature, a reduction in temperature is observed during contact lens insertion while the opposite is observed when the initial temperature is higher than the corneal temperature. The increase in evaporation rate when a contact lens is worn increases the cooling effect on the ocular surface. This is suggested to be the cause of lower corneal surface temperature when wearing a contact lens.