Comparative study of antibacterial effects of soft contact lens disinfection solutions

Author:T. Kuzman
Co-Author:R. Pokupec, M. Kalauz
Institute: Department of Ophthalmology, School of Medicine, University of Zagreb, Zagreb
Country: Croatia

Abstract:

Disinfection solutions need to keep soft contact lenses in a perfectly hygienic condition in order to avoid infection. There are several different contact lens disinfection solutions available, containing biguanides, hydrogen peroxide, polyquad or ammonium compounds. The aim of our study was to compare antibacterial efficiency of five commercially available soft contact lens disinfection solutions. Their ability to disinfect a saline solution experimentally contaminated with different bacteria was tested. The results of our study showed that contact lenses disinfection solutions have considerable variation in their antimicrobial activity.

One week of PMMA, medium- or high-Dk RGP orthokeratology extended wear; Histological outcomes in rabbit corneas

Author:M. Matsubara MD DMSc
Co-Author:K. Mukai , Y. Ishii
Institute: Dept. of Ophthalmol, Tokyo Women's Med Univ, Tokyo
Country: Japan

Abstract:

Aim To determine the relationship between hypoxia and redistribution of epithelial cells with different Dk orthokeratology lens (OK lens) wear by comparing the histological effect on the rabbit corneal epithelium. Methods Rabbits (n=18) were fitted with either a Dk 0 ( PMMA) , 33 or 95 OK lens and sacrificed after one week of continuous wear. HE, PAS and enzyme staining were performed on corneal tissues obtained from them. Results Redistribution of epithelial thickness was found in every cornea regardless of Dk values. At the area corresponding to the alignment curve zone of OK lens, the epithelium was thick with increased layers as many as 10 to 12. Epithelial edema was not observed. Central epithelium was very thin or detached in Dk 0 group. PAS staining showed decreased glycogranules in basal cells in Dk 0 group whereas no change was found in other groups. Lactic dehydrogenase and alkaline phosphatase showed slightly strong stainings, but there was no difference among the groups. Conclusion No conspicuous histological changes after adapted 1 week continuous wear of OK lens with Dk 33 or 95 suggest the good potential of epithelial adaptation to orthokeratology.

Alteration of keratoconus in time

Author:M. Stabuc Silih
Institute: University Medical Centre Ljubljana, Eye Clinic, 1000 Ljubljana
Country: Slovenia

Abstract:

Aim To evaluate visual function and eye specific health status in patients with keratoconus, searching for differences in time, gender and right – left eyes. Patients and methods The subjects of this study were selected from the file of 935 patients with keratoconus in the Eye Clinic of Ljubljana. Each patient’s medical records were reviewed. 113 patients (70 male and 43 female; 226 eyes), who came to our clinic from 1984 to 1990, were included in the study. History of eye-rubbing, visual acuity, refractive error, keratometric readings, slit-lamp examination, topography and Orbscan were recorded; each color-coded topographic map was evaluated using the movable cursor. Results The mean age of patients was 39.5±10.4 (at diagnosis 27.7±10.5 years women, 22.3±7.4 men), follow-up in years 14.5±6.5 women, 15.9±6.9 men. 61.1% of patients were rubbing their eyes. Visual acuity with glasses was 0.64±0.31 at the first visit and 0.54±0.31 at the last; VA with contact lenses 0.91±0.18 › 0.73±0.23; refractometry -2.59±2.46 Dsph -1.15±2.38 Dcyl › -3.58±4.17 Dsph -2.85±2.10 Dcyl; the highest value of keratometry 47.97±4.02 Dsph › 51.85±5.49 Dsph. Vogt striae were present in 35.4% right and 28.3% left eyes; Fleischer ring in 46% eyes. Correlations of scars and the steepest keratometry were: no scars - 48.34 Dsph, probably not - 52.92 Dsph, probably yes - 53.30 Dsph, surely yes - 55.08 Dsph. A cone was seen on topography in 83% right and 76.9% left eyes; in 66% the location was paracentral inferior. Statistical indices measured with Orbscan for maximal curvature (Dsph), maximal elevation (mm) and thinnest point (µm) showed that they were lo cated at different points [Correlation = 0.1786 for radius (mm) and 0.0374 for semimeridian (degree); Alpha = 0.3948 for radius and 0.1043 for semimeridian]. Conclusion We can conclude that rubbing is an important risk factor for keratoconus. This study gave us a deeper insight in the worsening of keratoconus in time.

Bacteriological investigation of contact lens solutions in cases of mild intolerance to soft contact lenses

Author:O.Frangouli
Co-Author:V. Daniilides, A. Kansouzidou, C.Frangoulis
Institute: Chelsea& Westminster Hospital, London, UK, Academic Department of Ophthalmology Aristotle University of Thessaloniki, Greece, University Hospital of Infectious Diseases, Thessaloniki, Greece, Thessaloniki
Country: Greece

Abstract:

Aim To investigate whether contaminated contact lens solutions can be the cause of clinical intolerance in patients wearing soft contact lenses (SCL). Patients and methods Twenty-six patients wearing soft contact lenses (SCL) and presenting circumcorneal injection and symptoms of mild intolerance to their lenses were selected. The patients' cleansing routines were documented and 99 specimens were collected as follows: 44 from contact lens cases, 45 from the various cleansing solutions used, 8 from bottles containing normal saline, 1 from 'a textile used for cleansing' and 1 specimen from a sucker. The specimens were investigated for bacterial and fungal contamination. In total, 99 cultures were performed. A sensitivity test was carried out for 30 isolated strains. Results Nineteen (73%) out of the twenty-six patients were found to use contaminated solutions and contact lens cases. In five (26.3%) out of these nineteen patients two different microorganisms were isolated, in one patient (5.2%) three microorganisms were isolated and in thirteen patients (68.5%) only one microorganism was isolated which was mainly gram-negative. The number of microorganisms ranged from 7,400 to 35,000,000 CFU/ml. Main microorganisms isolated were pseudomonas aeruginosa (47.3%), serratia marcescens (21.1%) and serratia liquefaciens (15.8%). There was no fungal growth in any of the cultures. Sensitivity tests carried out for 30 Gram negative microbial strains showed high sensitivity to amicacin (97%) and to gentamicin (77%). Conclusion Our study shows that the contamination of solutions used by patients for storing, cleaning or disinfecting their CLs can be the cause of irritation, clinical discomfort or intolerance to SCLs. Such cases should alert the practitioner in order to prevent progression to a major complication.

The role of KeraSoft DuraWave lenses in patients with irregular astigmatism

Author:R. Mathew
Co-Author:U. Vogt, M. Loutfi
Institute: Western Eye Hospital, London
Country: United Kingdom

Abstract:

Aim To evaluate the efficacy of Hioxifilcon B11 (KeraSoft DuraWave) soft contact lenses in the management of irregular astigmatism in patients intolerant of rigid contact lenses. Patients and methods A prospective non-randomised study of 16 patients (21 eyes) with irregular astigmatism, who had previously tried rigid gas-permeable lenses unsuccessfully, were fitted with the Hioxifilcon contact lens. Patients with irregular astigmatism of different aetiologies including keratoconus, post keratoplasty, post-trauma, aphakia with nystagmus were included. Results 15 of the 16 patients were very satisfied with comfort and fit of the DuraWave lenses. 13 out of 16 patients achieved visual acuities of 6/12 or better. 2 out of the 16 patients had a visual acuity of 6/18. 1 patient was dissatisfied with the visual outcome of the lens and chose to discontinue its use. Conclusion DuraWave provided a high degree of patient satisfaction both in terms of comfort and visual acuity. However the visual outcome was not as good as with rigid gas-permeable lenses. These soft contact lenses provide a comparable alternative in those patients unable to tolerate rigid gas-permeable contact lenses.

Multicenter, masked comparison of lotrafilcon B toric contact lenses to galyfilcon A toric contact lenses

Author:Jeffrey Sonsino
Co-Author:Priya Janakiraman
Institute: Vanderbilt Eye Institute, Nashville
Country: USA

Abstract:

Aim: To compare a recently launched silicone hydrogel toric contact lens, lotrafilcon B toric (LBT) lenses (O2 Optix Toric, CIBA Vision Corporation) to another silicone hydrogel toric contact lens, galyfilcon A toric (GAT) lenses (Acuvue advance for Astigmatism, Vistakon). Patients and methods: Ninety-seven habitual toric lens wearers were enrolled in a prospective, multi-center, single-masked, randomized, crossover study to wear LBT (monthly replacement) and GAT lenses (two-week replacement) on daily wear. Each period lasted for 4 weeks and included follow-up visits after 2 weeks (2W) and 4 weeks (4W). LBT lenses were hypothesized to be non-inferior to GAT (1-sided alpha=0.05). If the data supported this hypothesis, then 95% one-sided confidence limit on lens difference was computed to further determine superiority. Results: Average wearing time and comfortable wearing time were similar between the lenses. At 2W visit, LBT lenses displayed better centration, axis orientation and lens wetting compared to GAT lenses. GAT lenses demonstrated less edge lift after 2W. At 4W, LBT lenses had less front surface deposits than GAT lenses and significantly less conjunctival staining was noted. Average visual acuity was close to 20/20 with both lenses and did not differ by more than 0.20 lines (logMar). Subjective ratings for overall vision were also better for LBT lenses at 2W visits and were better for constant/stable vision and handling at 2W and 4W visits. LBT lenses were preferred over GAT lenses for handling (p<0.001, exact binomial test) and overall lens preference (p=0.010, exact binomial test) at 4W visits. Conclusion: After 2W, LBT lenses displayed better centration, axis orientation and lens wetting while GAT lenses displayed less edge lift. After 4W, LBT lenses had less front surface deposits and less conjunctival staining and were preferred for overall lens preference and handling.

Oxygen Transmission Characteristics of a Silicone Hydrogel Lens in Custom Parameters

Author:T. Giles
Co-Author:M. Fahmy, R. Singh, R. Weldon
Institute: CIBA Vision, Duluth
Country: USA

Abstract:

Aim: The introduction of silicone hydrogels produced using high volume manufacturing has made this technology accessible to the majority of the more than 89 million estimated contact lens wearers worldwide. There remains, however, a large population of contact lens wearers or potential wearers who, because of their need for extreme parameters, are unable to experience the benefits of silicone hydrogel materials. The availability of a silicone hydrogel material that could be produced in custom parameters could serve an estimated 1 million patients in North America and Europe alone. Patients and methods: Prototype lenses have been produced using an experimental silicone hydrogel material with a Dk of 82 (polarographic method) in high powers including +16.00D, -16.00D and -3.00-2.25x090. Lens thickness across the entire surface of each lens was measured and the Dk/t calculated and plotted. This procedure was repeated with traditional hydrogel materials (phemfilcon A/38% water, and methafilcon B/55% water) in corresponding powers. Results: The Dk/t maps demonstrate the enhanced oxygen transmission profile for the silicone hydrogel material compared with traditional hydrogel materials. This is especially evident in the high plus and high minus designs, where lens thickness increases considerably. Conclusion: Modern silicone hydrogel materials have dramatically transformed the landscape of contact lens practice in the 21st century. Clinical studies have shown fewer hypoxic signs among wearers of silicone hydrogel lenses, including reduced ocular redness, and a reduction in symptoms of dryness and end-of-day discomfort. The availability of these materials in expanded, custom parameters will allow practitioners to satisfy a previously unmet need among the patient population which stands to benefit the most from an enhanced oxygen profile.

Effect of Contact Lens Solutions on Corneal Surface

Author:J. E. Key
Co-Author:(This is part of the CLAO Symposium.)
Institute: Baylor College of Medicine, Houston, Texas
Country: USA

Abstract:

Aim: To investigate and quantify differences among contact lens multi-purpose solutions (MPS) as regards silicone hydrogel (SiH) lens wetting, corneal stress and patient comfort. Patients and methods: Laboratory videography was used to measure and compare wetting angles on SiH lenses preconditioned with various MPS. In addition, studies were performed on adapted contact lens wearers to quantitate corneal stress (staining), subjective rating of comfort and extent of lens coating. Results: There are demonstrable differences in wettability, staining and comfort among MPS. The copolymer, Tetronic 1304, demonstrated improved wettability and less corneal staining. Conclusion: Careful choice of MPS can affect patient comfort and success with SiH contact lenses and promote safer lens wear.

Trend for Prescription of Silicon Hydrogel Lens by Ophthalmologists and Lens Assessment by Patients.

Author:M. Cros - Boidevezi
Co-Author:L. Steve, R. Jouvencel, Clirophtha (C.R.O.)
Institute: CIBA Vision France, Paris
Country: France

Abstract:

Aim The primary aim of this prospective survey was to evaluate patient's satisfaction and behaviour after O2Optix™ lens prescription. Patients and methods Current soft hydrogel contact lens wearers needing correction compatible with O2Optix™ lens criteria were recruited. Ophthalmologists completed a questionnaire and patients were given O2Optix™ lenses with a diary to complete for 2 months. Patient’s satisfaction and comfort were assessed on a 10-point scale, respectively from “no satisfied/comfortable at all” (1) to “very satisfied/comfortable” (10). Results 400 ophthalmologists completed the questionnaire for 600 included patients. 41% of the patients consulted for lens renewal, 50% for usual control, 26% for problem with previous lens; 46% were satisfied from their previous lenses. After the first visit, O2Optix™ lenses were prescribed for about 95% of the patients and cleaning solution for 60%. After 7 days of wearing, though 50% of the patients had an adaptation phase, there was a statistical significant improvement (mean increase of 1.41 point) in patient's satisfaction for O2Optix™ lenses as compared to their previous lenses (p > 0.001), mean ± SD assessment for O2Optix™: 7.96 ± 1.74 versus 6.57 ± 2.13 with previous lenses. The mean assessment for comfort of O2Optix™ lenses was 8.06 ± 1.88. Similar results, with a higher mean satisfaction, were reported at further visits with ophthalmologist (8.03 ± 1.80, increase of 1.54) or optician/pharmacist (8.34 ± 1.48). At the final visit, the mean ± SD was 7.95 ± 2.12 for patient's satisfaction and 8.15 ± 2.09 for comfort. Regarding the other data: 23% of the patients changed their cleaning solution after seeing optician/pharmacist and 98% bought lens from optician (2% web purchase) attesting from their loyalty to the optician. Conclusion Results showed a very good comfort of O2Optix™ lenses and high patient’s satisfaction that timely increased and appeared to be better than with previous hydrogel lenses.

Experiences with a new Silicone Hydrogel Contact Lens for Astigmatism

Author:Ulrik Bengtsson
Institute: CIBA Vision NORDIC AB, Askim
Country: Sweden

Abstract:

Aim Silicone hydrogel contact lenses represent the fastest growing segment in the contact lens market with an increasing need for toric silicone hydrogel contact. To test themost recent silicone hydrogel contact lens for astigmatism, AirOptix™ Toric made from lotrafilcon B material, existing contact lens or spectacle wearing subjects were enrolled to wear AirOptix™ Toric and lens fit, visual acuity and subjective satisfaction for both wearers and practitioners was evaluated. Patients and methods An open-label, bi-lateral, single group, multi-center trial was conducted in NORDIC from December 2005 to June 2006. 39 investigators enrolled 328 contact lens and spectacle wearers to wear AirOptix™ Toric, with visits at dispensing and 2-4 weeks. Subjective results were measured using agreement questionnaire. Results 328 subjects completed the trial. Data of 262 to 324 subjects was analyzed. More than 82% of lenses oriented within 5° from horizontal, with 93% showing less than 3° oscillation with blink. 98% of lenses had an acceptable fit and 89% were symmetrically centered on the eye. 90% of overrefractions were within ±0.25 dpt and subjects achieved visual acuity comparable to habitual lenses. The majority of subjects were satisfied with AirOptix™ Toric, found the lenses comfortable to wear from insertion to the end of the day, and that they provided crisp, clear and stable vision. There was a statistically significant preference over the subject´s habitual contact lenses. 72% of the lenses fitted optimally, and all but 2% of fits were acceptable with a single basecurve. Conclusion AirOptix™ Toric was preferred over habitual toric lenses because it was comfortable to wear, provided good vision and was easy to handle. Practitioners found it easy to fit, with good stabilisation, which is essential for clear vision.

Ten year incidence of ocular surface disorders in contact lens wearers

Author:Bilić N
Co-Author:Čima I, Grgić D, Bilić L
Institute: "Bilić Vision" Ophthalmological Center, Zagreb
Country: Croatia

Abstract:

Aim To investigate the frequency of contact lens related ocular surface disorders. Design Retrospective, noncomparative, observational case series. Patients and methods Chart review was performed on 1102 patients who were examined and fitted with contact lenses in "Bilic Vision" Ophthalmological Center between the years 1996 and 2006. Findings associated with ocular surface disorders such as blepharitis, conjunctivitis and keratitis were reviewed. Statistical analysis was performed using chi-square test. Results Ocular surface disorders were present in 72 (7%) contact lens wearers (29 male and 51 female). The most common disorder was allergic/irritative conjunctivitis present in 41 (51%) patients, followed by infective conjunctivitis in 23 (29%), infective keratitis in 6 (7%) and infective blepharitis in 2 (3%) patients. Infectious disorders occured in 17 and 14 patients who wore coventional and disposable contact lenses, respectively (p<0.01). Fourteen patients (1%) had reccurent surface ocular disease. Ocular surface disorders were more common in patients with poor care compliance and/or overnight contact lens wear. Conclusion Allergic disorders were more common than infectious. Infectious disorders of the ocular surface were significantly more common in patients who wore conventional lenses. Educating patients about lens hygiene practice and dangers of the overnight wear could lower the incidence of these disorders.

Corneal Oxygen Consumption Maps

Author:N.Brennan
Co-Author:P.Morgan
Institute: Brennan Consulatnts. 110 Auburn Road , Auburn Village 3122 Melbourne
Country: Australia

Abstract:

Purpose: To determine the oxygenation across the corneal profile beneath soft contact lenses and plot the outcome as colour-coded maps. Method: Corneal epithelial thickness was assumed to be a constant 50 ľm across the cornea. Stromal thickness was estimated from OCT measures of Wang et al (2003). Lens thickness profiles were obtained from slivers of lenses measured by microscopy. Oxygen diffusion equations were used to determine consumption under chronic and acute conditions using the method of Brennan (2005). Acidotic effects were calculated by incorporating effects as described by Harvitt & Bonanno (1999). Corneal maps are plotted out to 11mm diameter; no allowance is made for limbal vasculature, or lid coverage of the cornea. Results: Available silicone-hydrogel lenses largely provide 100% of the corneal oxygen needs across the entire cornea for daily wear. Available traditional hydrogels do not meet the corneas needs across the profile for daily wear. No silicone-hydrogels entirely meet the cornea?s needs for extended wear. Contrary to common perception, increasing negative power and increasing corneal oxygen demand makes only modest relative difference to the appearance of the consumption maps between silicone-hydrogel lenses of different Dk/t values. Conclusions Relative oxygen consumption maps provide a novel and useful way to consider corneal oxygenation. More work is needed on input parameters and the importance of local corneal hypoxia to strengthen clinical interpretation.

Chlamydia Trachomatis in Contact lens wearers – Epidemiological incidence-three years follow -up regardless possible reinfection ( 2003- 2006 )

Author:J. Salopek-Rabatić
Institute: Clinical Hospital Dubrava , Visus Clinic Centar, Zagreb
Country: Croatia

Abstract:

Aim : Chlamydia trachomatis in Contact lens wearers : Epidemiological incidence -three year follow-up regardless possible reinfection (2003-2006 ) Patients and methods : The same group of C.L.W.patients (127) positive tested on Chl. Trachomatis infection by isolation of Chl. Trach. in cell culture of conjunctival scrapings on 2003 , were invited three year later ,2006 to be evaluated again. 110 (100 % ) patients were tested again ( identical test and procedure ) after therapy with a single 1 g oral dose of azithromycin three year earlier (2003 ) Results :All 110 (100 % )invited and tested patients with . C. L. passed examination under biomicroscopy during 2006. 8 % were positive again. Conclusion : Epidemiological incidence of Chl. Trachomatis positive C.L.W. or reinfection patients is 8 %.

Contact lens related complications & attendance at Accident and Emergency: A 12-month prospective study

Author:N.M. Muthiah
Co-Author:P.K. Jayia, S.M. George, U Vogt
Institute: Western Eye Hospital, St Mary's NHS Trust, London, NW1 5YE, London
Country: United Kingdom

Abstract:

Aim: To establish the complications relating to contact lens wear in patients attending the Accident and Emergency unit, London teaching hospitals. Patient & Methods: A 12 month (March 2005 to March 2006), prospective, hospital based questionnaire survey conducted in the 24 hour ophthalmic Accident and Emergency unit of an inner city teaching hospital. All patients who attended with contact lens related problems were requested to fill in the questionnaire recording personal details, presenting symptom(s), details of contact lens use and any previous contact lens problems. The examining ophthalmologist would document their diagnosis. Results: 290 patients completed the questionnaire, age range 10-80 years. 91.4% (265/290)used soft contact lenses with monthly disposables accounting for 43.4%(115/265) and daily disposables accounting for 36.6%(97/265). Rigid gas permeable contact lenses were only used by 7.6%(22/290). Most of the contact lenses 89.7%, were supplied by the optometrists, with only 6.6% being prescribed by the ophthalmologists. 2% obtained their contact lenses through Internet sources. The main presenting diagnosis was microbial keratitis (24.1%), followed by infective conjunctivitis (11.4%), over wear keratitis (7.2%) and corneal abrasion (6.9%). A significant proportion of cases 11.7% (34/290) were not directly related to contact lens wear. However patients still presented to Accident and Emergency with the perception that their eye problems were related to contact lens wear. Conclusion: Patients in the age group 21-30 accounted for the largest number of patients presenting to the department (114/290). Patients who developed microbial keratitis wore soft contact lenses and were noted to wear them for excessively long periods. The majority of patients purchased their contact lenses from their optometrists. Optometrists are in a unique position to educate patients to use contact lenses safely and prevent complications.

New prospects in the management of dry eye

Author:L.L. Mannucci
Co-Author:F. Mannucci
Institute: Department of Ophthalmology, Padova
Country: Italy

Abstract:

Aim To evaluate new prospects in the management of dry eye with two new polysaccharidic compounds. Materials and methods 1) arabinogalactan (acronym AG) is a natural polysaccharide from larch tree. We used Rheostress RS 150 ViscosimeterŽ , Micrometer eyepiece, and Shimadzu RF-551 FluorimeterŽ.. AG bioadhesion in vitro, precorneal residence time in rabbits and re-epithelisation speed in standardized corneal ulcers of twenty anaesthetized albino rabbits were measured. 2) "branched-chain" polysaccharides derive from tamarind (TSP, acronym of tamarind seed polysaccharide). By Fluorotron Master and Orthoplan Leitz Microscope, precorneal residence time and ferning properties of TSP were respectively evaluated in rabbits and in vitro. TSP ferning was compared with those of different lachrymal substitutes. Results 1) In spite of newtonian non-viscous behaviour ( ? = 1.6 mPa˙s for 10% w/w solution), AG 5% solution precorneal residence in rabbits was evident up to 60 minutes after instillation. The re-epithelisation speed of rabbit ulcers was more rapid with AG treatment (44 hrs.) in comparison to the controls (60 hrs. And longer). 2) TSP 0.5% solution showed a long precorneal permanence (8 hours); its ferning test was the only similar to the natural mucin. Conclusions 1) The long residence time of AG 5% solution derives from its high mucoadesive properties (? ?/ ? 17.21) as compared to hyaluronic acid (? ?/ ? 3.02). Moreover AG performed favorably in the re-epithelisation of experimental corneal ulcers. These preliminary data suggest the use of AG also in human subjects as artificial tear, especially in contact lens wearers for better comfort and possible reduced risk of corneal abrasions. 2) Among different marketed lachrymal substitutes, only branched-chain polysaccharides (TSP) have got a chemical structure similar to transmembrane mucins (as MUC I); ferning test "type 1" confirmed "mucin like" properties. Summarizing, the two compounds have opposite characteristics and different indications. TSP, as mucomimetic, is recommended when mucous layer is absent; AG, as mucoadhesive, is indicated when mucous layer is altered, but not greatly reduced. For these reasons, an exact diagnosis of dry eye is fundamental for opportune therapy.

Rigid bifocal contact lenses

Author:Catherine Peyre
Institute: Paris
Country: France

Abstract:

The fitting with contact lenses for presbyopia is nowadays dominated by soft Multifocal disposable lenses. You may yet find extremly performant multifocal RGP, being more and more sophisticated, with revolution design or toric design, witch allow the correction of all amétropias. Usual wearers as well as new ones may wear this type of lenses. These made to measure lenses allow the best visual acuity whithout any compromise, whithout loss of contrast vision, and thanks to new materials, it gives an opportunity of extended wear. Throughout this presentation, we are going to describe the design of the new lenses. Concentric with center distance vision, concentric with center near vision, and segmented bifocal lenses. We will then see which may be modified to carry out made to measure lenses: BOCR, the diameter, the height of lower segment, the prism power, and the possible use of troncature. or not. At last we will study the results obtained with these different type of lenses.

Monovison outcomes in presbyopic individuals with contact lenses and after refractive surgery

Author:Zdravko Mandic
Co-Author:Dean Saric
Institute: Eye Clinic, Clinical Hospital “Sisters of Charity”, VisuMed laser Center, Zagreb
Country: Croatia

Abstract:

Aim To analyze the results of contact lenses wearing and laser in situ keratomileusis (LASIK) for monovision in myopes and hyperopes. Patients and methods In this retrospective study 197 patients older than 40 years were treated by monovision. 108 were fitted with contact lenses and 89 had LASIK between December 2003 and June 2006. All patients were asked to complete a questionnaire, and study results were based on the analysis of data from patient charts correlated with questionnaire responses. All LASIK patients underwent trial monovision period with contact lenses Results Visual results were satisfying in both groups, with all monovision patients achieving uncorrected visual acuity 0,9 or better in the distance eye and 0,9 or better acuity in the near eye. Statistical analysis indicated that visual outcome was better in myopes, but overall satisfaction was higher among hyperopes. Monovision patients had the most difficulty with night vision glare. Conclusion Contact lenses or LASIK monovision is acceptable solution to correct presbyopia in selected patients.

A novel biomimetic sruface on a contact lens?

Author:C.A Morris
Co-Author:M. Willcox, L. Winterton, J. Lally
Institute: Southern Cross University, Lismore, NSW
Country: Australia

Abstract:

INTRODUCTION: Nelfilcon A and nelfilcon A with added non-functional PVA both exhibit sustained release of small amounts non-functional PVA into the tear film during wear. The release is triggered by the eyelid blink, and counterbalanced by the build-up of a reservoir of surface PVA, in readiness for release. PURPOSE: To examine the effects of release of PVA from contact lenses on tear film stability and behaviour. METHODS: The non-invasive surface drying times (NISDTs) over 6 hours, and the presence of an intact lipid layer, of both nelfilcon A lenses and nelfilcon A with added PVA lenses were evaluated in two masked studies. Firstly, 41 subjects wore the lenses contralaterally, and secondly, 10 subjects wore each lens bilaterally. The results were compared to historical data from HEMA Group IV lenses. RESULTS: In the contralateral study, nelfilcon A and nelfilcon A with added PVA lenses on insertion displayed NISDTs of 14.5 ±10.0s and 17.3±9.7s respectively, much higher than previously recorded for HEMA Group IV lenses (10.1±5.1s). After 6 hours wear, the longer NISDTs for both lens types were essentially sustained. In the bilateral study, the NISDT values upon insertion and at 6 hours for nelfilcon A mirrored those in the contralateral study. However NISDTs at 6 hours for nelficon A with added PVA rose to levels equivalent to tear break up times over the cornea (23.0±17.0s). The lipid layer appearance over both lens types was strong over the 6 hour wear period, contrary to that recorded on HEMA Group IV lenses. CONCLUSION: Tear film stability over nelfilcon A and nelfilcon A with added PVA lenses was greatly enhanced over that on conventional hydrogel lenses, and can be attributed to the sustained release of PVA. The surface of these lenses is constantly renewed, driven by the action of the blink, allowing the formation of a stable tear film, and no build up of debris, protein and lipid, mimicking the surface of natural cornea .

Comparison of conventional and silicone hydrogel contact lenses for Bullous Keratopathy.
Author:N. Lim
Co-Author: U. Vogt, G. Clare
Institute: Western Eye Hospital, London
Country: United Kingdom

Abstract:

Aim: To compare the efficacy and safety of conventional lenses and silicone hydrogel lenses in the treatment of bullous keratopathy. The silicone hydrogel bandage contact lenses used were Focus® Night & Day® and PureVision®. The conventional lens used was Sauflon 85%. Patients and methods: This was a prospective, comparative study of 22 patients with painful bullous keratopathy in one eye. Patients attended a specialist contact lens department and were fitted with all 3 different lens type in their affected eye for 1 month each, for a total duration of 3 months. The main outcome measures were comfort and pain relief, which patients scored for using a scoring scale that ranged from 1 to 5; 1 being very poor, 5 being excellent. Doctors assessed the fit of lens, movement and any deposit build-up. The statistical tests applied were the Kruskal Wallis and the Mann-Whitney test. Results: 16 out of the 22 patients (24 eyes) successfully completed one months’ wear of all three bandage contact lenses (BCL). The median comfort score was 3.9 for PureVision®, 3.8 for Focus® Night & Day® and 2.8 for the Sauflon 85% lens, showing a statistical siginificance between the 3 groups (p=0.031). Silicone hydrogel lenses performed better than conventional lenses for comfort. The Mann-Whitney test showed that there was no statistically significant difference for comfort scores of Focus® Night & Day® versus PureVision® (p<0.782) as well as of Focus® Night & Day® versus Sauflon (p<0.073). However, there was a statistically significant difference for comfort scores of PureVision® versus Sauflon 85% (p<0.0136). The median pain relief score was 3.8 for PureVision®, 3.7 for Focus® Night & Day®, and 3.2 for Sauflon. There was no significant difference between the 3 lenses for pain relief score. All 3 lens types were similarly good with regards to contact lens fit, movement and deposit build-up. Conclusion: The use of silicone hydrogel lenses are a safe and effective alternative to conventional contact lenses for the treatment of bullous keratopathy.

Subjective tolerance of a new Silicone Hydrogel lens of second generation: 54 cases

Author:R. Pagot MD
Institute: Strasbourg
Country: France

Abstract:

AIM: To assess subjective performance including overall satisfaction, comfort and with? OASYS?vision of the senoficon A contact lenses -(ACUVUE Plus from Johnson?HYDRACLEAR &Johnson Vision Care) amongst neophytes and existing soft contact lens wearers. METHODS: An anonymous questionnaire about subjective satisfaction in different wearing conditions was sent to 104 senofilcon A contact lenses wearers over a nine month period. Response options were based on a 5 points scale. RESULTS: 54 patients sent back the questionnaire and the average wearing period was 5.4 months. In all cases tolerance was judged excellent/good either for new wearers (11) or for previous wearers (43) of hydrogel or silicone hydrogel lenses. Among the 43 previous wearers, 40 have preferred the new lens to their habitual lens. CONCLUSION: This new second generation silicone hydrogel lens achieved high subjective satisfaction from new and existing contact lens wearers, with a majority preferring senofilcion A over their habitual lens

Cinical recorded cases history of 14 children wearing RGP lenses during their growth

Author:Stéphane Fiat Rubolini
Institute: Nice
Institute: Nice
Country: France

Abstract:

Aim The author has presented 14 clinical cases of myopic chidren wearing RGP lenses during their growth. Patients and methods The population group who has been studied is classified as: 8 girls and 6 boys all suffering from bilateral myopia, which bring the total to 28 eyes. The values of average K readings go from 7.30 to 8.00; 20 eyes / 28 are between 7.60 and 7.80. 10 eyes only from 28 show astigmatism: 7 of which under or equal 0.50. The population group has been classified in 2 categories: 1/ 18 eyes within which the evolution has been recorded first with glasses then with contact lenses on an average lapse of time of 15 years 2/ 10 eyes recorded with rigid contact lenses only on an average lapse of time of 8.5 years Results The myopia evolution in those populations has been less important in the group which were wearing contact lenses Conclusion The end result seems to be more pronounced that in the studies already done before, but it is not a randomized study, since this is a clinical recorded cases history. The author will debate the gain of the young myopic to use rigid contact lenses.