Tick-borne encephalitis (TBE) epidemiology in the Brest Province of the Republic of Belarus

BACKGROUND: Lens adherence and a reduced postlens tear film circulation have been suggested as factors contributing to some adverse reactions in extended wear of hydrogel contact lenses. In this study, we determined lens fitting and postlens tear film characteristics during closed-eye wear. METHODS: Twenty subjects wore hydrogel lenses for 3 h of eye closure, followed by 30 min of open-eye wear. Lens movement was measured with a video biomicroscope. Postlens tear film appearances in specular reflection were classified as either amorphous, or as one of four color intensity grades, where a colored appearance was taken as indicative of a depleted postlens tear film. RESULTS: All subjects showed lens adherence (movement < 0.1 mm) and postlens tear film depletion within 45 min of eye closure. These changes were sustained for the remainder of the closed-eye period, but were reversed within 15 min of eye opening. Lens adherence was associated with colored postlens tear film patterns of any intensity. CONCLUSION: Closed-eye wear was invariably associated with the onset of lens adherence and postlens tear film depletion. This finding emphasizes the need for adequate lens movement during the open-eye phase of extended wear.     

Effect of proteolysis on the state of lipid phase in rat brain synaptosomal membranes

Polymethylmethacrylate (PMMA) contact lenses can alter corneal shape and induce corneal warpage or distortion. The purpose of our study was to determine the effects on the corneal topography after immediate refitting of long-term PMMA contact lens wearers into rigid gas permeable (RGP) materials. Six eyes with contact lens induced corneal warpage from PMMA contact lenses were assessed using the Topographical Mapping System-1. Statistical analysis was performed for the following variables prior to and approximately 6 months after contact lens refitting: best spectacle visual acuity, manifest refraction, surface regularity index, surface asymmetry index, keratometry, and simulated keratometry. Best spectacle visual acuity improved an average of 1.8 +/- 1.0 (mean +/- SD, P < 0.05) lines of Snellen visual acuity, while refraction did not change appreciably. The surface regularity index diminished by 0.51 +/- 0.32 (P = 0.01). The surface asymmetry index improved by 0.32 +/- 0.26 (P < 0.05). There was a good correlation between keratometry and simulated keratometry, and neither changed significantly after refitting with RGP contact lenses. All general topographic patterns remained unchanged throughout the study. Immediate refitting of long-term PMMA contact lens wearers into RGP materials of similar fit allows a slightly more regular and symmetric central corneal shape, which can result in improved spectacle visual acuity. The general corneal topographic patterns of contact lens induced corneal warpage did not change or improve after refitting to RGP material.     

Effect of topical anesthetic use on initial patient satisfaction and overall success with rigid gas permeable contact lenses

BACKGROUND: Rigid gas permeable (RGP) contact lenses have numerous benefits; however, RGP lens use is not increasing in the United States. An important factor for this trend has been initial comfort. Studies have demonstrated that how RGPs are presented to patients, in addition to lens design, can play an important role in the initial comfort process. Another important factor could be the use of a topical anesthetic during the fitting and dispensing visits. The purpose of this study was to use a multicenter format to determine if topical anesthetic use increased the likelihood of patient satisfaction and success. METHODS: A total of 80 subjects, with no previous rigid lens wear experience, was entered into this 1-month study, including 20 subjects from each of 4 institutions. Subjects were randomly divided into the following two groups: (A) anesthetic or (B) placebo, with the former group receiving one drop of a topical anesthetic before lens insertion at both the diagnostic fitting and dispensing visits, whereas the latter group received a placebo. Subjects completed a questionnaire on their perception of rigid lens wear both immediately before fitting and at the 1-month visit. After diagnostic fitting with rigid lenses, subjects completed an adaptation questionnaire after 15 min, 1 week, 2 weeks, and 1 month of lens wear. RESULTS: Seventy of the 80 subjects completed the study and, of the 10 subjects who discontinued, 8 were in the placebo group. In all categories evaluated, the anesthetic group experienced a more optimum adaptation experience at each visit vs. the placebo group. Specifically, overall comfort was rated significantly higher at both dispensing and 2 weeks. In addition, the anesthetic group exhibited significantly greater overall satisfaction with rigid lens wear at 2 and 4 weeks. Also, the anesthetic group perceived their adaptation, sensitivity, and adaptation time to be significantly better at the 1-month visit. There was no significant difference in corneal staining between these two groups at each visit, with the exception of a greater amount of staining in the central quadrant for the placebo group at the 1-month visit. CONCLUSIONS: The use of a topical anesthetic at the fitting and dispensing visits for first-time wearers of RGP lenses resulted in significantly fewer dropouts, improved initial comfort, an enhanced perception of the adaptation process, and greater overall satisfaction after 1 month of lens wear as compared to the use of a nonanesthetizing placebo at those visits. This result, in combination with both presenting RGP lenses in a nonthreatening manner and optimizing the lens design and fitting relationship, should result in a positive adaptation process and successful wear of RGP contact lenses.     

Disposable contact lenses and their complications

Disposable soft contact lenses (DSCLs) have been marketed as a safer alternative to conventional soft lenses. Extended-wear DSCLs are designed for one or two weeks of continuous use before disposal. Those for daily wear are designed for use as conventional daily wear soft lenses, with daily removal and storage for 2 to 4 weeks before disposal. Beside minor complications, such as corneal abrasion, giant papillary conjunctivitis and toxic epithelial reactions to contact lens solutions, the most serious complication occurring in contact lens users is ulcerative keratitis. Several case-control studies performed over the last years, demonstrated that disposable contact lenses were associated with a 14-fold excess risk of ulcerative keratitis compared with that for patients wearing conventional daily-wear soft contact lenses and a 13-fold excess risk compared with that for wearers of rigid gas permeable contact lenses. However, the major risk factor for corneal ulceration in contact lens wearers is overnight lens wear of 1 to 3 nights. It was estimated that 49 to 74% of cases of contact lens associated ulcerative keratitis could be prevented by eliminating overnight wear.     

Infiltrative keratitis with contact lens wear--a review

BACKGROUND: "Infiltrates" of white blood cells aggregating in the superficial cornea are common with corneal inflammation. The etiologies of such inflammation vary widely and include an association with contact lens wear. METHODS: This paper reviews the literature regarding corneal infiltrative keratitis with contact lens wear. Basic mechanisms in the development of corneal infiltrates as well as etiologies are presented. Associations and causes, clinical presentation, differential diagnosis, course, and treatment for corneal infiltrates in contact lens wearers are reviewed. CONCLUSIONS: Corneal infiltrates associated with contact lens wear may stem from a variety of causes including factors related to the lens material, design, condition; the lens wearing schedule; environmental factors such as external environment; and lens care patterns, procedures, and products. Individuals who wear contact lenses are also subject to the many non-contact lens-related stimuli to corneal infiltration. Accurate diagnosis and appropriate management of corneal infiltrates with contact lens wear is important, especially due to the possibility of infectious etiology.     

Comparison of corneal versus through-the-lid A-scan ultrasound biometry

BACKGROUND: Accurate ultrasonography data on axial ocular dimensions in infants and toddlers are essential for understanding ocular development. Conventional methods using corneal contact with topical anesthesia but without sedation are not feasible for most of these patients. We evaluate an alternative method which places the probe on the closed eyelid. METHODS: We compared A-scan ultrasound biometry measurements taken with the probe directly on the cornea with those with the probe on the closed eyelid on the right eye of 35 young adult subjects. RESULTS: There was no significant difference between methods for mean anterior chamber depth (corneal = 3.83 mm, lid = 3.87 mm, p = 0.13, paired t-test). The mean lens thickness (corneal = 3.63 mm, lid = 3.75 mm, p = 0.0001, paired t-test) and mean vitreous chamber depth (corneal = 17.50 mm, lid = 17.68 mm, p = 0.0440, paired t-test) were significantly different. CONCLUSION: Ultrasonography through the closed eyelid appears to be a viable method with acceptable validity compared with corneal ultrasound. Poorer agreement for lens thickness and vitreous chamber depth may be undesirable, but these data should be useful for planning future studies of infants and toddlers.     

Gender differences in psychosocial profile at entry into cardiac rehabilitation

PURPOSE: To assess whether the contact lens to cornea-bearing relationship, as determined from the fluorescein pattern, can be predicted from videokeratography. METHODS: Nineteen non-rigid gas permeable (RGP) lens wearers were each tested for fluorescein patterns with a series of seven RGP contact lenses of different base curves, and compared to a theoretical estimate of the fitting relationship from videokeratography. The experimentally determined alignment lens was then compared to the theoretical alignment (TA) value as determined from the central curvature and eccentricity. RESULTS: The mean difference in lens choice between the TA and experimental alignment (EA) values was -0.01 +/- 0.04 mm and between the simulated keratometric (KA) readings and the EA choice was 0.11 +/- 0.05 mm. CONCLUSION: A knowledge of the eccentricity value from videokeratography allowed a better prediction of the base curve to cornea relationship than was provided by only a central corneal measurement.     

Enhanced hepatotoxicity of acetaminophen in the alcoholic patient. Two case reports and a review of the literature

PURPOSE: Bacterial adherence or binding to the target cell is a prerequisite for the initial stage of most infections and seems to be mediated by lectin-like ligands on the bacterial surface and specific receptors on the target cell membrane. The purpose of this study was to establish whether contact lens wear under closed eye conditions changes the glycocalyx layer, whether it exposes more lectin receptors than eye closure without a contact lens, and whether wear of low oxygen transmissibility (Dk/L) contact lenses exposes more receptors than high Dk/L contact lenses. METHODS: The eyes of six rabbits under general anesthesia were fit with either a high Dk/L soft contact lens (40 x 10(-9), boundary corrected) or a low Dk/L soft contact lens (2 x 10[-9]) or were left without a lens as controls. All eyes were kept closed by suturing for 24 hours. After removal of the contact lenses, all corneas were excised, put in glutaraldehydeforfixation, rinsed, incubated with plant-derived lectins (wheat-germ agglutinin [WGA]) conjugated with gold particles, and prepared for electron microscopy. Membrane associated gold particles were counted and the results were processed statistically. RESULTS: After 24 hours of lens wear under closed eye conditions, the glycocalyx layer showed physical changes in the form of thinning or compression and signs of biochemical changes reflected as an increase in number of WGA receptors. The average number of membrane associated gold particles per 750 micro length of corneal epithelium in control corneas was 1,287.5 +/- 92.5. Particles were significantly (P<0.001) more numerous after wear of high Dk/L contact lenses (3,230.0 +/- 294.5) and after wear of low Dk/L contact lenses (4,611.3 +/- 223.3). The figure after wear of low Dk/L contact lenses was significantly (P<0.01) higher than the figure after wear of high Dk/L contact lenses. CONCLUSION: Our results indicate that lens wear under closed eye conditions seems to change the corneal glycocalyx layer physically as well as biochemically. Significantly larger numbers of WGA receptors were exposed after contact lens wear than without a contact lens. Significantly more receptors were exposed after wear of low Dk/L contact lenses than after wear of high Dk/L contact lenses. These changes may be of importance in relation to the risk of bacterial keratitis.     

MEG and EEG topography of frontal midline theta rhythm and source localization

PURPOSE: We studied a case of corneal ulceration in utero from lower eyelid entropion. METHODS: A 3-week-old male infant was referred for examination of a left corneal ulcer that was present at birth and unresponsive to antibiotics. RESULTS: Examination disclosed a lower eyelid entropion that was treated surgically by a nonincisional method, leaving a central leukoma after re-epithelialization. CONCLUSION: Congenital lower eyelid entropion should be included in the differential diagnosis of congenital corneal opacities.     

Clinical evaluation of Acuvue contact lenses with UV blocking characteristics

BACKGROUND: In response to increasing scientific evidence which indicates that ultraviolet radiation (UVR) is a potential threat to ocular health, Acuvue contact lenses (Vistakon, Johnson & Johnson Vision Products Inc., Jacksonville, Florida) have been developed which incorporate an ultraviolet (UV) blocker within the lens polymer. Data are presented for the first clinical evaluation of Acuvue lenses with UV blocking characteristics. METHOD: A double-masked, multicenter, prospective clinical trial involving 94 subjects was conducted. The study followed a randomized, parallel group design and consisted of 3 months of daily wear with two-weekly lens replacement. Two thirds of the subjects (61) wore the test lenses (Acuvue with UV blocker) and the remaining subjects (33) wore conventional Acuvue lenses (without UV blocker). RESULTS: Biomicroscopic evaluations indicated that the performance of the test and control lenses was clinically similar. No clinically relevant differences between the test and control lenses were noted in the subjective assessments of vision, comfort, or handling. In addition, no differences were shown for surface deposition, lens durability, visual acuity, and subjective symptoms. CONCLUSION: The study findings indicate that the addition of a UV blocker to Acuvue contact lenses has been achieved without affecting daily wear clinical performance. Because there is increasing evidence to suggest that the ocular tissues may be damaged by UVR, it is prudent for eye care practitioners to prescribe contact lenses that offer the benefits of both regular replacement and UV protection.     

Corneal response to orthokeratology

PURPOSE: The technique of orthokeratology produces a corneal response to the mechanical pressures exerted by rigid contact lenses. This paper reports a study which investigated the topographic and pachometric corneal changes induced by orthokeratology. METHODS: Six young myopic subjects (11 eyes) wore "accelerated orthokeratology" lenses (OK-74; Contex Inc., Sherman Oaks, CA) in a high Dk material (AirPerm; Dk = 88) for 28 days. Corneal and epithelial thickness were measured topographically using the Holden-Payor optical micropachometer, and corneal topography was monitored using the EyeSys system. RESULTS: Refractive error change reached 1.71 +/- 0.59 D reduction in myopia after 28 days. After 1 day of lens wear, statistically significant central corneal flattening was noted, which progressed to reach 0.22 +/- 0.07 mm (1.19 +/- 0.38 D) at 28 days. A trend toward central epithelial thinning was apparent, reaching statistical significance on day 28 (7.1 +/- 7.1 microm; 9.6%). Midperipheral corneal thickening was also found approximately 2.5 mm from the corneal center, which was statistically significant by day 14 (13.0 +/- 11.1 microm; 2.4%). Calculations using Munnerlyn's formula indicate that changes in corneal sagittal height based on topographical thickness changes across the flattened central 5.25-mm zone can account for the refractive changes observed. CONCLUSIONS: These findings suggest that the initial corneal response to orthokeratology may be explained by redistribution of corneal tissue, rather than by overall bending of the cornea.     

Further data on biometric correlations of central corneal thickness

Central corneal thickness measured in 126 young men aged from 18-21 years was correlated to a number of ocular and other parameters. The frequency distribution was skewed towards the lower end, but the deviation could not be statistically supported. No correlation between corneal thickness and birth weight was found. Other characteristics not correlated in this material to corneal thickness were corneal astigmatism, refraction, visual acuity, optic disc and retinal abnormalities, red-green colour vision defects, ABO and rhesus blood-groups, EEG abnormalities, chromosomal abnormalities, hearing defects, ear abnormalities and quality of the hair. The findings in this study, although mainly of negative character, stress the relative independence of the central corneal thickness as a biometric parameter.     

Paclitaxel and carboplatin in combination in the treatment of advanced non-small-cell lung cancer (NSCLC): a preliminary study

The effects of rigid contact lens material [polymethyl methyacrylate (PMMA) and itabisfluorofocon A] and prism ballasting (0, 1.5, 2.25, and 3 delta) on tear pump efficiency were studied by measuring corneal oxygen uptake rates on the right eyes of six human subjects under three conditions: (1) normal open eye; (2) after 5 min of static (without blinking) wear of the contact lens; and (3) after 5 min of dynamic (with blinking once every 5 s) wear of the same lens. As expected, corneal oxygen uptake rates (i.e., demand for oxygen) measured with the itabisfluorofocon A material were significantly lower (p < 0.0001) than those measured with PMMA under both static and dynamic conditions. Under static conditions, no significant differences were found across materials among the corneal oxygen uptake rates associated with the four amounts of prism ballasting (p = 0.0514). However, under dynamic conditions, significant differences (p < 0.0001) were found across materials among corneal oxygen uptake rates associated with the four amounts of prism ballasting, with the lower amounts of prism ballasting being associated with lower corneal oxygen uptake rates. The changes in the measured corneal oxygen uptake rates from static to dynamic conditions, relative to those measured for the normal open eye, served as an index of tear pump efficiency. There were no significant differences in these changes for the prism amounts studied; however, static condition data were significantly higher than dynamic condition data for the 0 delta and 1.5 delta lenses only, whereas greater amounts of prism ballasting resulted in no reduction in oxygen uptake under dynamic conditions. In addition, significantly greater differences between static and dynamic condition data were found for the PMMA material than for itabisfluorofocon A.     

Characterization of sports by the VO2 dynamics of athletes in response to sinusoidal work load

The determinants of postlens tear film (PTF) composition in hydrogel lens wear are poorly understood, although this layer has important roles in lens movement and corneal integrity. We investigated the hypothesis that the PTF could be depleted by instillation of hypotonic saline, using a randomized, double masked, placebo controlled study design. Solutions of 0.90, 0.60 and 0.45% NaCl were instilled into the eyes of 12 subjects wearing ionic and non-ionic high water content hydrogel lenses. Postlens tear film appearances in specular reflection were categorized as amorphous, faint coloured or coloured, where the coloured patterns represent a progressive thinning of the PTF. With instillation of the hypotonic solutions (0.60 and 0.45% NaCl), the appearance of the PTF in specular reflection changed to a faint coloured or coloured pattern in at least 67% of subjects for each lens type (Friedman ANOVA, P < 0.002). For the 0.45% NaCl solution, median lens movement decreased from 0.50 to 0.10 mm (Friedman ANOVA, P = 0.02); however, there were no significant changes in measured lens parameters and no difference between lens types. Postlens tear film depletion due to a hypotonic shift in tear osmolality, as demonstrated here, may explain the clinically observed phenomenon of lens binding.     

Chalazion-induced hyperopia as a cause of decreased vision

This article presents three cases of decreased vision due to acquired hyperopia, which were caused by a chalazion of the upper eyelid. Through manifest refraction and computerized corneal topographic analysis, acquired hyperopia associated with central corneal flattening was revealed. These findings were responsible for the blurred vision that was reversed by chalazion resolution or removal. Although not usually considered a risk factor for refractive disorders other than astigmatism, chalazia of the upper eyelid can present as a decrease in vision associated with reversible central corneal flattening and acquired hyperopia.     

Early clinical diagnosis of acanthamoeba keratitis. A study of 70 eyes

BACKGROUND: Acanthamoeba keratitis is an uncommon condition which is usually associated with contact lens wear. The use of home made saline and poor hygiene are important risk factors. Early diagnosis is crucial since these cases respond well to medical therapy. The purpose of this paper is to describe and demonstrate early clinical signs. METHOD: Between September 1992 and October 1994, 70 cases of acanthamoeba keratitis, one of them bilateral, were prospectively monitored at Moorfields Eye Hospital in London. A database of all patients was set up and the clinical findings, diagnostic methods, therapeutic interventions and the outcome were recorded. RESULTS: 66 patients (96%) were contact lens wearers, 64 of them (97%) wore soft lenses. The mean interval between first symptoms and correct diagnosis was 42%. The most frequent initial diagnoses were "unclear keratoconjunctivitis" and "herpetic keratitis". Early corneal findings included punctate keratopathy (n = 14; 20%), pseudodendrites (n = 4; 6%), epithelial infiltrates (n = 17; 24%), diffuse or focal sub-epithelial infiltrates (n = 36; 51%) and radial keratoneuritis (n = 5; 7%). Ring infiltrates (n = 13; 18%) and corneal ulceration (n = 13) were late signs. CONCLUSION: When the above corneal findings are observed, particularly in contact lens wearers, the diagnosis of acanthamoeba keratitis should be considered. The diagnosis of "herpetic keratitis" in association with contact lens wear should be encountered with scepticism.     

Eyelid imbrication. An unrecognized cause of chronic ocular irritation

BACKGROUND: Eighteen patients with chronic ocular irritation were examined over a 3-year period. All patients demonstrated papillary conjunctivitis and, occasionally, tarsal ulcers. Six also had floppy eyelid syndrome. Underlying every patient's symptoms was the overriding or imbrication of a lax upper eyelid on an often equally lax lower eyelid, allowing lower eyelid lashes to chronically rub the upper eyelid tarsal conjunctiva. METHODS: Chronic ocular irritation in five patients was managed with ocular lubricants. Two of these patients had floppy eyelid syndrome and required nightime shielding for nocturnal eyelid eversion. Thirteen patients underwent eyelid surgery to correct the overriding upper eyelid. Surgical procedures included full-thickness upper eyelid wedge resection, lateral canthal tendon plication, and lower eyelid horizontal shortening, using a tarsal strip procedure. RESULTS: Follow-up averaged 2.5 years. Symptomatology was adequately controlled in all patients. In addition to the five patients who received medical treatment for their symptoms, two with complicated ocular problems required continued ocular lubrication after surgery. Seven patients were successfully treated with eyelid shortening procedures and lateral canthal tendon plication. The remaining six patients underwent a variety of additional eyelid surgeries. All patients undergoing surgery had complete resolution of eyelid imbrication. CONCLUSIONS: Eyelid imbrication is a previously unrecognized cause of chronic ocular irritation. In this condition, eyelid laxity causes the upper eyelid to override the lower eyelid, allowing the lower eyelid to chronically rub and chafe the upper eyelid tarsal conjunctiva. In some cases, symptoms can be managed medically. More often, surgical intervention is required to correct eyelid laxity and prevent overriding of the upper eyelid.     

Disposable contact lens use as a risk factor for microbial keratitis

AIMS: A case-control study was performed to evaluate soft contact lens (SCL) wear modality as a risk factor for microbial keratitis. METHODS: Contact lens wearers presenting as new patients to Moorfields Eye Hospital accident and emergency department during a 12 month period completed a self administered questionnaire detailing demographic data and contact lens use habits. Cases were patients with a clinical diagnosis of SCL related microbial keratitis. Controls were SCL users attending with disorders unrelated to contact lens wear. Odds ratios (estimates of relative risks) and 95% confidence limits (CL) were calculated through multivariable logistic regression analysis. RESULTS: There were 89 cases and 566 controls. A substantially increased risk with 1-4 weekly disposable SCL compared with non-disposable SCL was identified among both daily wear (DW) (odds ratio = 3.51, 95% CL 1.60-7.66, p = 0.002) and extended wear (odds ratio 4.76, 95% CL 1.52-14.87, p = 0.007) users after adjustment for demographic, lens use and hygiene variables. Other significant factors among DW users were "occasional" overnight use, use of chlorine based (as opposed to other chemical) systems in combination with poor storage case hygiene, and irregular disinfection. CONCLUSION: Properties of some disposable SCL may be partly responsible for these excess risks. It is also possible, however, that this finding is largely a reflection of widespread complacency among patients and practitioners with respect to disposable SCL fitting and use.     

Laparoscopic ventral hernia repair: a community hospital experience

OBJECTIVE: To study the suitable age for intraocular lens (IOL) implantation in children. METHODS: 240 (240 eyes) normal children aged 3-13 years old were selected. Their corneal refraction, anterior chamber depth, lens thickness and ocular axial length were measured with Roden-Stock Keratometer C-MES and Eyescan Model 55 separately. RESULTS: The corneal refraction of 3-year-old children, the anterior chamber depth and lens thickness after 5 years old, and the ocular axial length after 9 years old approach the adult magnitude. CONCLUSIONS: A 3-year-old child has been qualified with IOL implantation, the child younger than 9 years old should be implanted with a normal adult IOL and then corrected with glasses, and a child after 10 years old should be directly implanted with a proper dioptric IOL.