Months Of Wear Research Articles

The effects of silicone hydrogel lens wear on the corneal epithelium and risk for microbial keratitis.

Previous studies using animal models and human clinical trials have demonstrated that the use of low-oxygen-transmissible contact lens materials produce corneal epithelial surface damage resulting in increased Pseudomonas aeruginosa (PA) adhesion and raft-mediated internalization into surface corneal epithelial cells. These findings led to the testable clinical predictions that (1) microbial keratitis (MK) risk is expected to be the greatest during the first 6 months of wear; (2) there is no difference between 6 and 30 night extended wear; and (3) that wear of hyperoxygen-transmissible lenses would reduce the reported incidence of infection. Subsequent epidemiologic studies have confirmed the first two predictions; however, increased oxygen transmissibility with silicone hydrogel (SiHy) lens wear has not altered the overall incidence of MK. In this review, more recent clinical and basic studies that investigate epithelial alterations and bacterial adhesion to corneal epithelial cells after the wear of SiHy lenses with and without concomitant exposure to chemically preserved multipurpose solutions (MPS) will be examined. The collective results of these studies demonstrate that even in the absence of lens-related hypoxia, MPS induce ocular surface changes during SiHy lens wear that are associated with a pathophysiologic increase in PA adherence and internalization in the corneal epithelium, and therefore, predict a greater risk for PA-MK. In addition, new data supporting an interactive role for inflammation in facilitating PA adherence and internalization in the corneal epithelium will also be discussed.

Ocular physiology and comfort in neophyte subjects fitted with daily disposable silicone hydrogel contact lenses

To evaluate the performance of a silicone hydrogel daily disposable lens in neophyte subjects over 12 months. Seventy four subjects with no previous contact lens experience were randomised to wear narafilcon A (1 DAY ACUVUE(®) TruEye™) lenses (LW group) or to wear no contact lenses (NLW group) for 12 months. Biomicroscopy (performed by a masked investigator), visual acuity and subjective response scores were recorded at an initial visit and six follow-up visits, in addition to lens fit and surface evaluation for the LW group. Comfort was recorded with SMS messaging. Fifteen of the LW group discontinued before the end of the study, compared with six of the NLW group. Measured visual acuity was about half a line better for the NLW group as these subjects were provided with their full sphero-cylindrical over-refraction, compared to the LW group in their best spherical corrected contact lenses; subjective scores for vision were similar for the two groups. Bulbar conjunctival hyperaemia, limbal hyperaemia, corneal staining, conjunctival staining and papillary conjunctivitis were clinically equivalent for the two groups whereas conjunctival staining was higher in the LW group. Comfort scores assessed by SMS were equivalent for the LW and NLW groups; there was a measurable improvement in comfort during the first month of wear for the LW group. This work has demonstrated that modern soft lenses (narafilcon A daily disposable silicone hydrogel lenses) offer an excellent, comfortable form of vision correction, and are able to exhibit minimal alterations to ocular physiology.

Patient experiences with the Forsus Fatigue Resistant Device

To investigate patients' experiences with the Forsus Fatigue Resistant Device (FFRD). This was a survey focused on patient's comprehensive experience with FFRD, both initially and after several months of wear, including the patient's overall impression of the appliance. The survey was administered to 70 patients wearing FFRD in both university and private practice settings. A high percentage (81.5%) reported a neutral to favorable experience with FFRD; 89.8% reported growing accustomed to the appliance within 4 weeks. The majority of those who had previously worn rubber bands found FFRD to be "easier." Cheek irritation was the most serious side effect (about 50%). Cheek irritation and other negative effects generally decreased over time. The FFRD is relatively well accepted by patients. Most patients experience some discomfort and functional limitations; however, the effect generally diminishes with time, and patients adapt to the appliance. Practitioners should be especially vigilant about problems with cheek irritation.

Biomechanical and Clinical Outcomes With Shock-Absorbing Insoles in Patients With Knee Osteoarthritis: Immediate Effects and Changes After 1 Month of Wear

Turpin KM, De Vincenzo A, Apps AM, Cooney T, MacKenzie MD, Chang R, Hunt MA. Biomechanical and clinical outcomes with shock-absorbing insoles in patients with knee osteoarthritis: immediate effects and changes after 1 month of wear. ObjectivesTo examine the effectiveness of shock-absorbing insoles in the immediate reduction of knee joint load, as well as reductions in knee joint load, pain, and dysfunction after 1 month of wear, in individuals with knee osteoarthritis (OA). DesignPre-post design with participants exposed to 2 conditions (normal footwear, shock-absorbing insoles) with a 1-month follow-up. SettingUniversity laboratory for testing and general community for intervention. ParticipantsCommunity-dwelling individuals (N=16; 6 men, 10 women) with medial compartment knee OA. InterventionParticipants were provided with sulcus length shock-absorbing insoles to be inserted into their everyday shoes. Main Outcome MeasuresPrimary outcome measures included the peak, early stance peak, and late stance peak external knee adduction moment (KAM); the KAM impulse (positive area under the KAM curve); and peak tibial vertical acceleration. Secondary outcomes included walking pain, the Western Ontario and McMaster Universities Osteoarthritis Index pain subscale and total score, and a timed stair climb task. ResultsThere was a significant reduction in the late stance peak KAM with shock-absorbing insoles (P=.03) during follow-up compared with the baseline test session. No other immediate or longitudinal significant changes (P>.05) in the other KAM parameters or peak tibial acceleration after use of a shock-absorbing insole were observed. However, significant improvements in all measures of pain and function (P<.05) were observed. ConclusionsShock-absorbing insoles produced significant reductions in self-reported knee joint pain and physical dysfunction with 1 month of wear in patients with knee OA despite no consistent changes in knee joint load. Further research using randomized controlled trials, with larger sample sizes and explorations into long-term use of shock-absorbing insoles and their effect on disease progression, is warranted.

Comfort and Vision Scores at Insertion and Removal During 1 Month of Wear of Paragon CRT for Corneal Reshaping

The goal of this study was to evaluate the pattern of initial adaptation of neophytes to corneal refractive therapy (CRT) for overnight corneal reshaping in terms of comfort and subjective visual performance at lens insertion at night and lens removal in the morning. Twenty-two young healthy subjects were enrolled in this study. All of them had been trialed to assess adaptation to conventional alignment-fit rigid gas permeable lenses and were only enrolled in this study after a 2-week wash-out period. Visual analog scales for subjective comfort and vision were recorded on a form given to the patient on days 1, 2, 3, 5, 7, 14, 21, and 28. Additionally, the patient attended the clinic on days 1, 7, 15, and 30 after fitting, for follow-up. Successful adaptation was obtained in 21 of the 22 initially enrolled individuals. The average overnight wearing time remained constant during the study at 8 hrs per day. Overall comfort rates increased significantly up to values of 8.02 and 9.12 out of 10 at insertion and removal, respectively (P<0.001). Subjective vision scores also increased significantly at the end of the 1-month study period (P<0.001). Adaptation to CRT is rapid in terms of subjective comfort and vision. Comfort significantly increases by day 5, whereas subjective vision in the morning reaches its maximum by days 15 to 21 and at the end of the day by days 10 to 15. These results are of interest to clinicians to provide evidence-based information to their patients about the expected time to adapt to CRT in terms of self-reported comfort and vision.

Evaluation of the pressure-redistributing properties of prefabricated foot orthoses in older people after at least 12 months of wear

Foot problems are highly prevalent in older people. To treat such problems in this age-group prefabricated (‘off-the-shelf’) foot orthoses are frequently prescribed. However, such devices are susceptible to material compression and deformation, which may reduce their effectiveness over time. Therefore, the aim of this study was to compare the pressure-redistributing properties of new prefabricated orthoses to orthoses worn for at least 12 months. Thirty-one adults (10 males, 21 females) aged over 65 years (mean 75.4, SD 5.2) participated. Plantar pressure data were collected under the rearfoot, midfoot and forefoot using the Pedar ® in-shoe system while participants walked along an 8 m walkway wearing shoes only, new orthoses and old orthoses (orthoses were full length, dual-density prefabricated Formthotic™ devices). Compared to the shoe-only condition, both the new and old orthoses produced significant reductions in peak pressure and maximum force in the rearfoot with corresponding increases in force and contact area in the midfoot. Compared to the new orthoses, the old orthoses exhibited small but significant increases in peak pressure in the rearfoot (6%, p = 0.001) and maximum force in the rearfoot (5%, p < 0.001) and forefoot (2%, p = 0.032). These findings indicate that the prefabricated orthoses evaluated in this study are only slightly less effective at redistributing plantar pressure after at least 12 months of wear.

Short-term Effects of Overnight Orthokeratology on Corneal Cell Morphology and Corneal Thickness

To examine the morphological and biometric corneal changes produced over periods of 15 days and 1 month after overnight orthokeratology (OK). Prospective, single-center, longitudinal trial. Twenty-seven right eyes of 27 subjects (group 1) with low to moderate myopia wore OK lenses for 1 month. Ten right eyes of 10 subjects (group 2) with emmetropia to low myopia who did not wear any type of contact lens served as controls. Corneal morphometric measurements were obtained in vivo using a confocal microscope to examine the central and midperipheral cornea. Thickness measurements in the peripheral cornea were obtained by optical coherence tomography. Changes in visual acuity, refractive error, and corneal topography were also analyzed. No significant changes in either endothelial cell or stromal cell density were observed after 1 month of OK. Basal epithelial cells were, however, significantly reduced (P < 0.01), and epithelial wing and superficial cells showed enhanced visibility (P < 0.05). Superficial cells increased in height and width, the width increase after 1 month being significant (P < 0.01). Epithelial thickness was significantly reduced in the central cornea and 2 mm around the center. Corneal pachymetry increased significantly in the band from 5 to 10 mm from the corneal apex (P < 0.01). OK lenses for myopia induce significant structural and optical changes particularly in the central epithelium after 15 days or 1 month of wear. The central corneal epithelium responds to OK wear by undergoing significant epithelial cell shape and size alterations with no effects, however, on the cells of the corneal endothelium or the corneal stroma. Peripheral corneal thickness increased with respect to baseline values. These findings suggest that the corneal epithelium is the principal structure affected by the mechanical forces exerted by the OK lenses.

Are prefabricated foot orthoses still effective in reducing plantar pressures after 12 months of wear?

midfoot (new=42%, old=44%), and contact area at the midfoot (new=51% and old=53%) and forefoot (new=11%, old=13%) compared to the shoe only condition. There were no significant differences between the old and new orthoses, with the exception of small but statistically significant increases in peak pressure at the heel (6%) and maximum force at the heel (5%) and forefoot (2%) in the old orthoses compared to the new orthoses.

Prefabricated zirconium dioxide implant abutments for single‐tooth replacement in the posterior region: evaluation of peri‐implant tissues and superstructures after 12 months of function

In the present study, prefabricated abutments made of zirconium dioxide Y-TZP (tetragonal zirconia polycrystals) were inserted into the posterior region under controlled clinical conditions. The aim was to test whether abutments made of zirconium dioxide are suitable for this indication. Investigation parameters included reactions of peri-implant tissue and the structural integrity of the all-ceramic superstructures on the implants. Results after 12 months in function are reported in this article. Forty implants of the XiVE S plus screw-type implants (DENTSPLY Friadent) were inserted into the posterior region of 24 patients. After the healing period, the implants were provided with all-ceramic abutments made of zirconium dioxide Y-TZP (FRIADENT CERCON Abutment; DENTSPLY Friadent). All-ceramic crowns (CERCON smart ceramics; DENTSPLY DeguDent) were used as superstructures and cemented using the conventional method. The following parameters were used to document the state of soft tissue: modified plaque index (mPI), sulcus fluid flow rate (SFFR, Periotron; Oraflow Inc), modified sulcus bleeding index (mSBI) and pocket depth (ST). Mesial and distal bone levels were determined on radiographs during the prosthetic treatment and at the 12-month recall. The Periotest (Medizintechnik Gulden) was used to determine implant stability. All implants could be followed up after 12 months in function. In the presence of good oral hygiene (mPI: 0.5), the parameters SFFR (18) and mSBI (0.5) were indicative of stable and healthy soft tissue. ST was highest at the distal points of measurement (2.3 mm) and was generally at a low level. Compared with the baseline situation, proximal bone defects were reduced from -1.1 to -1 mm during the 12-month period of functioning. The mean Periost values at the 12-month recall were -1.9 in the maxilla and -3.8 in the mandible. Neither implant loss nor crown fractures occurred. Chipping of parts of the veneering ceramic was registered in four cases (10%). After 12 months of wear, no mechanical failure was registered in any of the all-ceramic abutments. On clinical investigation, the peri-implant hard and soft tissues were largely healthy and devoid of inflammation.

Advantages of a non-linear frequency compression algorithm in noise

A multichannel non-linear frequency compression algorithm was evaluated in comparison to conventional amplification hearing aids using a test of speech understanding in noise (Oldenburger Satztest-OLSA) and subjective questionnaires. The new algorithm compresses frequencies above a pre-calculated cut off frequency and shifts them to a lower frequency range, thereby providing high-frequency audibility. Low-frequencies, below the compression cut off frequency, are amplified normally. This algorithm is called SoundRecover (SR). In this study, 11 experienced hearing aid users with a severe to profound sensorineural hearing loss were tested. Seven subjects showed enhanced levels of understanding in noise (OLSA) using frequency compression. However, 4 out of the 11 subjects could not benefit from the high-frequency gain. Evaluation using questionnaires demonstrated an increased level of satisfaction after 2 months of experimental devices wearing (p = 0.08) and after 4 months of wearing (p = 0.09), respectively, compared to conventional hearing instruments.

Changes in knee adduction moment, pain, and functionality with a variable‐stiffness walking shoe after 6 months

This study tested the effects of variable-stiffness shoes on knee adduction moment, pain, and function in subjects with symptoms of medial compartment knee osteoarthritis over 6 months. Patients were randomly and blindly assigned to a variable-stiffness intervention or constant-stiffness control shoe. The Western Ontario and McMaster Universities (WOMAC) score served as the primary outcome measure. Joint loading, the secondary outcome measure, was assessed using the external knee adduction moment. Peak external knee adduction moment, total WOMAC, and WOMAC pain scores were assessed at baseline and after 6 months. The total WOMAC and WOMAC pain scores for the intervention group were reduced from baseline to 6 months (p = 0.017 and p = 0.002, respectively), with no significant reductions for the control group. There was no difference between groups in magnitude of the reduction in total WOMAC (p = 0.50) or WOMAC pain scores (p = 0.31). The proportion of patients achieving a clinically important improvement in pain was greater in the intervention group than in the control group (p = 0.012). The variable-stiffness shoes reduced the peak knee adduction moment (-6.6% vs. control, p < 0.001) in the 34 intervention subjects at 6 months. The adduction moment reduction significantly improved (p = 0.03) from the baseline reduction. The constant-stiffness control shoe increased the peak knee adduction moment (+6.3% vs. personal, p = 0.004) in the 26 control subjects at 6 months. The results of this study showed that wearing the variable-stiffness shoe lowered the adduction moment, reduced pain, and improved functionality after 6 months of wear. The lower adduction moment associated with wearing this shoe may slow the rate of progression of osteoarthritis after long-term use.

Laterally wedged insoles in knee osteoarthritis: do biomechanical effects decline after one month of wear?

ObjectiveThis study aimed to determine whether the effect of laterally wedged insoles on the adduction moment in knee osteoarthritis (OA) declined after one month of wear, and whether higher reported use of insoles was associated with a reduced effect on the adduction moment at one month.MethodsTwenty people with medial compartment OA underwent gait analysis in their own shoes wearing i) no insoles and; ii) insoles wedged laterally 5° in random order. Testing occurred at baseline and after one month of use of the insoles. Participants recorded daily use of insoles in a log-book. Outcomes were the first and second peak external knee adduction moment and the adduction angular impulse, compared across conditions and time with repeated measures general linear models. Correlations were obtained between total insole use and change in gait parameters with used insoles at one month, and change scores were compared between high and low users of insoles using general linear models.ResultsThere was a significant main effect for condition, whereby insoles significantly reduced the adduction moment (all p < 0.001). However there was no significant main effect for time, nor was an interaction effect evident. No significant associations were observed between total insole use and change in gait parameters with used insoles at one month, nor was there a difference in effectiveness of insoles between high and low users of the insoles at this time.ConclusionEffects of laterally wedged insoles on the adduction moment do not appear to decline after one month of continuous use, suggesting that significant wedge degradation does not occur over the short-term.

Risk Factors for Contact Lens Bacterial Contamination During Continuous Wear

Microbial contamination of contact lenses is associated with corneal infection and inflammation. This study determined the microbiological, clinical, and demographic factors that are associated with bacterial contamination of a silicone hydrogel contact lens when worn for continuous wear (CW). Two hundred five healthy subjects were enrolled in the Longitudinal Analysis of Silicone Hydrogel Contact Lens Study and were fitted with lotrafilcon A lenses for monthly CW and followed for 1 year. Lenses were aseptically removed after 1 week and 4 months of wear and cultured using an agar sandwich technique. Lids and conjunctiva were routinely cultured at baseline and after 1 week and 4 months of CW. Lenses and ocular sites were considered to have substantial microbial bioburden when they harbored pathogenic organisms or high levels of commensal organisms. Univariate and multivariate logistic regression analyses were conducted to examine whether substantial conjunctival or lid bioburden, subject demographics, lens-wearing history, symptoms, and biomicroscopic signs were associated with lens bioburden. About one third (32.4%) of subjects had substantial bacterial bioburden in either eye across multiple visits. Over half (53.2%) and about one tenth (11.7%) of subjects had substantial lid and conjunctival bioburden, respectively, and 11.2% discontinued because of discomfort. The adjusted odds ratios (and 95% confidence intervals) for presence of substantial lens bioburden were 2.49 (1.17-5.30), 4.24 (1.45-12.40), and 4.11 (1.17-14.46) for substantial lid bioburden, substantial conjunctival bioburden, and lens discomfort, respectively. Bacterial contamination of silicone hydrogel contact lenses is common during CW. Substantial lens bioburden is associated with discomfort precluding successful CW. The presence of substantial lid and conjunctival bioburden is associated with a 2.5-fold and more than fourfold greater risk of substantial lens bioburden and is likely the major route of contamination.

Influence of induced decentered orthokeratology lens on ocular higher-order wavefront aberrations and contrast sensitivity function

To quantitatively evaluate the effect of overnight orthokeratology lenses intentionally left decentered after 3 months of wear and assess the influence on clinical outcomes such as ocular higher-order wavefront aberrations and contrast sensitivity function. Department of Ophthalmology, Tsukuba University Hospital, Ibaraki, Japan. This prospective study assessed refraction, visual acuity, corneal topography, wavefront aberration, and contrast sensitivity function before and 3 months after overnight orthokeratology treatment. Decentration of the treatment zone from the center of the entrance pupil was determined using computerized videokeratography (TMS-4) and data-analysis software (MatLab). The relationship between decentration and the clinical parameters was analyzed. The mean age of the 23 patients (46 eyes) was 24.2 years+/-3.3 (SD) and the mean spherical equivalent refraction before treatment, -2.38+/-0.98 diopters. The mean magnitude of decentration (0.85+/-0.51 mm) was statistically significantly correlated with the amount of myopic correction (P<.05), increases in coma-like aberration (P<.01), increases in spherical-like aberration (P<.01), and reductions in contrast sensitivity function (P<.0001). Changes in contrast sensitivity function were also statistically significantly correlated with the amount of myopic correction (P<.05), changes in coma-like aberration (P<.01), and changes in spherical-like aberration (P<.01). Stepwise multiple regression analysis showed that the magnitude of decentration was the only explanatory variable related to contrast sensitivity function (P<.0001). Decentered treatment of orthokeratology resulted in decreased contrast sensitivity after treatment, showing that centration of the procedure is crucial to good outcomes.

Protein Deposition on a Lathe-Cut Silicone Hydrogel Contact Lens Material

To determine the quantity of total protein, total lysozyme, and the conformational state of lysozyme deposited on a novel, lathe-cut silicone hydrogel (SiHy) contact lens material (sifilcon A) after 3 months of wear. Twenty-four subjects completed a prospective, bilateral, daily-wear, 9-month clinical evaluation in which the subjects were fitted with a novel, custom-made, lathe-cut SiHy lens material. The lenses were worn for three consecutive 3-month periods, with lenses being replaced after each period of wear. After 3 months of wear, the lenses from the left eye were collected and assessed for protein analysis. The total protein deposited on the lenses was determined by a modified Bradford assay, total lysozyme using Western blotting and the lysozyme activity was determined using a modified micrococcal assay. The total protein recovered from the custom-made lenses was 5.3 +/- 2.3 microg/lens and the total lysozyme was 2.4 +/- 1.2 microg/lens. The denatured lysozyme found on the lenses was 1.9 +/- 1.0 microg/lens and the percentage of lysozyme denatured was 80 +/- 10%. Even after 3 months of wear, the quantity of protein and the conformational state of lysozyme deposited on these novel lens materials was very similar to that found on similar surface-coated SiHy lenses after 2 to 4 weeks of wear. These results indicate that extended use of the sifilcon A material is not deleterious in terms of the quantity and quality of protein deposited on the lens.

The Clinical Performance of a Silicone Hydrogel Lens for Daily Wear in an Asian Population

To evaluate slitlamp findings, frequency and severity of symptoms, and wearing time with a silicone hydrogel contact lens when used for daily wear by patients of Asian ethnicity. This was a five-site, 88-patient, prospective, open-label study involving 1 month of daily wear of lotrafilcon A lenses (Focus NIGHT & DAY, CIBA Vision, Duluth, GA) among adapted soft lens wearers previously wearing etafilcon A (ACUVUE 2, Johnson & Johnson Vision Care, Jacksonville, FL) or polymacon (Optima FW, Bausch & Lomb, Rochester, NY) lenses. Statistically significant improvements in conjunctival redness, limbal redness, and corneal neovascularization were reported after 1 week and 1 month of wear. Patients reported statistically significant improvements in subjective symptoms of redness, dryness during the day, and dryness at the end of the day. More patients reported increased than reduced average daily wear time and average daily comfortable wear time with the silicone hydrogel lens. Significant improvements in clinical signs and subjective symptoms may occur when some patients of Asian ethnicity wearing conventional hydrogel lenses for daily wear are refitted with silicone hydrogel lenses for daily wear.

Rewetting Drops Containing Surface Active Agents Improve the Clinical Performance of Silicone Hydrogel Contact Lenses

The purpose of this study was to investigate the impact of using a rewetting drop (RWD) containing surface active agents (OPTI-FREE RepleniSH; Alcon, Fort Worth, TX) on the clinical performance and protein deposition when using a continuous-wear (CW) silicone hydrogel (SH) contact lens. Subjects wore lotrafilcon A SH lenses on a 30-day CW basis for two consecutive 1-month periods while inserting either 0.9% unpreserved unit-dose saline (control) or multidose OPTI-FREE RepleniSH (test RWD). Subjective comfort and symptoms were assessed after 2 and 4 weeks with each product. After 1 month of wear with each product, lenses were collected and analyzed in the laboratory for total protein, total lysozyme, and percentage of denatured lysozyme. Symptoms of dryness and comfort varied across the day regardless of drop type (p < 0.001) with dryness being maximal on waking, least in the middle of the day, and increased towards the evening. The test RWD provided greater comfort on insertion (p = 0.02), better visual quality (p < 0.01), and less mucous discharge on waking (p = 0.02) than the control product. Lysozyme deposition was significantly reduced after the use of the test RWD as compared to saline (0.73 +/- 0.5 microg/lens vs. 1.14 +/- 0.7 microg/lens; p < 0.001) as was total protein deposition (1.17 +/- 0.7 microg/lens vs. 1.86 +/- 0.8 microg/lens; p < 0.001). Lysozyme denaturation was also reduced with the use of the test RWD compared with the control (76 +/- 10% vs. 85 +/- 7%; p < 0.01). The use of a RWD containing surface active agents provided greater subjective satisfaction, reduced lysozyme and total protein deposition, and reduced denatured lysozyme than a RWD containing saline alone.

Short-Term Adaptation of the Human Corneal Endothelium to Continuous Wear of Silicone Hydrogel (Lotrafilcon A) Contact Lenses After Daily Hydrogel Lens Wear

The purpose of this study is to assess whether improved oxygen availability to the cornea resulted in changes in the corneal endothelium. Eighteen adult (average age 25.3 +/- 5.1 years) hydrogel lens wearers (average of 5.5 years prior daily lens wear, range 3-9 years) were refitted with silicone hydrogel lenses (Focus Night and Day) for continuous wear over 30 days and nights. They were assessed in detail immediately before the refit (baseline measures) and again after 6 months of wear with lens replacement every 30 days. Assessments included slit biomicroscopy (for grading of limbal and bulbar redness), corneal staining with fluorescein, and then by noncontact specular microscopy for central corneal thickness (CCT) and endothelial cell layer images. The endothelial images exported as JPEG files and printed at 7000x magnification. The cell-cell borders were marked and then the areas of an average of 255 cells/image measured with a digitizer pad in stream mode. The number of cell sides was also counted. After 6 months of silicone hydrogel lens wear, most subjects showed an improvement in mean bulbar (1.1 to 0.9) and limbal redness (1.0 to 0.6, p < 0.001) and epithelial fluorescein staining (0.5 to 0.3) grades, and the mean CCT values decreased slightly in most subjects (0.527 to 0.520 mm), although the decrease was not statistically significant (p = 0.565). The mean endothelial cell area also increased slightly (358 to 363 microm2; p nonsignificant [NS] = 0.701), whereas the mean coefficient of variation (COV) decreased slightly (30.2 to 29.1%, p NS = 0.357). The calculated mean endothelial cell density (ECD; area/1000000 microm2) also decreased slightly from 2821 to 2774 cells/mm, but this change also was not statistically significant (p = 0.620). However, the changes in ECD showed a very substantial relationship to the changes in CCT, i.e., as CCT decreased, so the apparent ECD decreased; this change was highly significant (r = 0.747, p < 0.001). This relationship was slightly stronger still when possible image magnification differences were corrected for. The percentage of six-sided ("hexagonal") cells increased slightly (58.3 to 60.1%). The results indicate that, in silicone hydrogel lens wearers exhibiting positive external eye signs thought to be associated with improved oxygen availability, subtle morphologic changes (marginally decreased polymegethism and pleomorphism) in the central region of the corneal endothelium can occur. It remains to be established, however, whether these changes can be directly attributed to oxygen effects (reduced hypoxia and hypercapnia altering the endothelial cells) or to a mechanical effect (in which changes in corneal thickness result in a reorganization of the corneal endothelium).

Influence of different types of partial dentures on dental plaque accumulation

The aim of the paper was to assess influence of different types of partial dentures on dental plaque accumulation. The study was conducted in three experimental and one control group with 30 examinees each. In the first experimental group were patients with partial acrylic dentures, in the second were patients with overdentures and in the third group were the patients with metal skeletal dentures. Dental plaque on the remaining teeth was measured by Silness-Loe modified method. Dental plaque scores were obtained at a time when dentures were given to patients and after 6 and 12 months of wearing, respectively. The plaque index of all teeth after 12 months of wearing dentures was relatively low in all three examined groups which resulted from previous education and motivation of examinees for oral hygiene maintenance. However, the highest risk of oral diseases caused by dental plaque is in patients with partial acrylic dentures, then in patients with overdentures, and best preventive effect was achieved in patients with metal skeletal dentures.

A modified monobloc for the treatment of obstructive sleep apnoea in paediatric patients

The aims of this study were to determine the differences in craniofacial morphology between children with obstructive sleep apnoea (OSA) and control subjects, and to investigate the effects of modified monobloc (MM) appliance treatment in OSA children. The treatment group consisted of 20 OSA Caucasian subjects (10 boys and 10 girls) with ages ranging from 4 to 8 years (mean 5.91 years). The control group comprised 20 healthy Caucasian subjects without OSA (10 boys and 10 girls) with ages ranging from 5 to 7 years (mean 6 years). Polysomnography was used to establish the diagnosis of OSA and to evaluate the effects of MM treatment in the test group. Cephalometric radiographs and study models were obtained for all subjects. A number of statistically significant differences were detected in craniofacial morphology between the treatment group and controls. The treatment group demonstrated a skeletal Class II pattern (P= 0.04), with a reduced mandibular length (P= 0.03) and a corresponding increase in overbite. The hyoid bone was located superiorly in the OSA group (P = 0.04). Analysis of the dental arches demonstrated a significantly smaller distance between the first and second inter-molar primary mandibular regions (P = 0.03 and P = 0.04, respectively) in OSA patients. Repeat polysomnography, with the MM in situ, after 6 months of wear, revealed a significant reduction in the apnoea-hypopnoea index in children with OSA (P= 0.0003). The MM was found to reduce daytime sleepiness and to subjectively improve assessed sleep quality. The patients and their parents reported good compliance with MM treatment.