Contact lens & anterior eye: the journal of the British Contact Lens Association

Publications in this journal

• Article: Response to geis et Al.

  Adeela Malik, Charles Claoué
  Contact lens & anterior eye: the journal of the British Contact Lens Association 06/2013; 36(3):152.
• Article: Specialist contact lens fitting.

  Shehzad A Naroo
  Contact lens & anterior eye: the journal of the British Contact Lens Association 06/2013; 36(3):105.
• Article: Comparison of normal and keratoconic corneas by Galilei Dual-Scheimpflug Analyzer.

  Selim Demir, Barış Sönmez, Volkan Yeter, Hüseyin Ortak
  [show abstract] [hide abstract]
  ABSTRACT: BACKGROUND AND OBJECTIVE: To determine the efficacy of different Galilei Scheimpflug-Analyzer (GSA) parameters in discriminating between keratoconic and myopic eyes. PATIENTS AND METHODS: GSA measurements were obtained for 67 patients (67 eyes) with keratoconus and 151 patients (151 eyes) with myopia or myopic astigmatism. Several parameters, provided by the software or derived from the elevation maps, were evaluated and compared for the two groups. RESULTS: Between the two groups, statistically significant differences were observed for all corneal parameters obtained by GSA (P<0.001) except for the anterior chamber depth (P=0.149). ROC analysis determined that posterior corneal elevation was the best predictive parameter (area under the curve: 0.99). The posterior corneal elevation, at a cut-off value of 18.5μm, had 98.5% sensitivity and 98.3% specificity in discriminating keratoconus from myopic eyes. CONCLUSION: Elevation, pachymetric and keratometric parameters measured by the GSA, as well as the specific predictive GSA software parameters can effectively distinguish advanced keratoconus from myopic corneas. Also, keratoconus that is easily diagnosed by other means can be diagnosed easily by GSA software parameters.
  Contact lens & anterior eye: the journal of the British Contact Lens Association 04/2013;
• Article: In vitro power profiles of daily disposable contact lenses.

  Lurdes Belda-Salmerón, David Madrid-Costa, Teresa Ferrer-Blasco, Santiago García-Lázaro, Robert Montés-Micó
  [show abstract] [hide abstract]
  ABSTRACT: PURPOSE: To evaluate and compare the distribution of refractive power within the optic zone of different soft contact lenses and to investigate the effect of lens decentration on the power profiles. METHODS: The Nimo TR1504 instrument was used to measure the optical power across different aperture diameters (from 1.5mm to 5.5mm in steps of 0.5mm) of four daily disposable contact lenses: DAILIES TOTAL1, Proclear 1-Day, SofLens daily disposable and 1-DAY ACUVUE MOIST. Measurements were performed using a wet cell. Power data were evaluated when contact lenses were in its centered position and after inducing different amounts of lens decentration (from 0.2mm to 1.0mm in steps of 0.2mm). RESULTS: All contact lenses showed an increase - more negative - in lens power with distance from the lens center. The amount of change varied depending on the lens. It was about 10% of lens power for DAILIES TOTAL1 (-0.29diopters (D)), SofLens daily disposable (-0.36D), and Proclear 1-Day (-0.32D) whereas 1-DAY ACUVUE MOIST showed a percentage variation of 3.3% (-0.10D). After inducing a lens decentration up to 1mm, the power curves were shifted in the negative direction. However, the change obtained in lens power compared with well-centered position was always lower than a quarter of diopter both for all the lenses and aperture diameters. CONCLUSIONS: Our results showed a variation of the refractive power from the lens center, becoming more negative toward the periphery, with a negligible effect of the decentration for all disposable contact lenses studied.
  Contact lens & anterior eye: the journal of the British Contact Lens Association 04/2013;
• Article: A brief review of techniques used to seal corneal perforation using cyanoacrylate tissue adhesive.

  M Rana, V Savant
  [show abstract] [hide abstract]
  ABSTRACT: INTRODUCTION: There are many modalities in use to treat corneal perforations. One of most commonly used modality these days is the use of tissue adhesive. Cyanoacrylate adhesive is the commonest type of tissue adhesive used. PURPOSE: To describe various techniques used for corneal glueing with cyanoacrylate tissue adhesive and to suggest a new technique for the same. METHODS: We describe here a brief review of different techniques of tissue glue application and suggest a modified new technique to apply tissue glue over the area of corneal perforation to achieve a nice smooth and stable seal. The importance of good glueing technique is to provide a stable and a closed wound so that it can help the epithelium grow and close the perforation. RESULTS: We present three different techniques of corneal glueing to seal corneal perforations. CONCLUSION: These different techniques of glueing can be used to seal corneal perforations. It is up to the reader to try all three techniques and then follow whichever gives the best and smooth results.
  Contact lens & anterior eye: the journal of the British Contact Lens Association 04/2013;
• Article: Trend of soft contact lens prescribing in an optometry centre in India: A 6-year analysis.

  Nijil Sanker, Babu Noushad
  [show abstract] [hide abstract]
  ABSTRACT: This six-year retrospective longitudinal study was conducted to examine the changes in the pattern of prescribing soft contact lenses in an optometry centre located in a University in South India. Details regarding the type of lenses, lens material, wearing pattern and the clinical diagnoses were analyzed from January 2006 to December 2011. A total of 1273 soft contact lens fits (n=1273) were analyzed. Two-third of the total lenses dispensed was for females and their mean age (24.0±8.3yrs) was less than that of male (27.0±11.2yrs) lens users. Nearly 70% of them had myopia and 48% wore conventional soft contact lenses. During the studied six years, the percentage of conventional lenses declined by 60%. This study demonstrated a gradual and significant increase in popularity of disposable contact lenses and silicone hydrogel lens material which is comparable to the global trend.
  Contact lens & anterior eye: the journal of the British Contact Lens Association 04/2013;
• Article: Evaluation of central corneal thickness after cataract surgery, penetrating keratoplasty and long-term soft contact lens wear.

  Saadettin Sel, Stefanie Trau, Matthias Knak, Thomas Kalinski, Delia Kaiser, Friedrich E Kruse, Cord Huchzermeyer, Gernot I W Duncker, Friedrich Paulsen, Gerd U Auffarth, Norbert Nass
  [show abstract] [hide abstract]
  ABSTRACT: PURPOSE: The aim of this study was to compare central corneal thickness (CCT) between corneas of normal healthy eyes (cNHE), corneas of eyes that had undergone cataract surgery by clear corneal phacoemulsification with implantation of an intracapsular intraocular lens (cIOL), corneal grafts after penetrating keratoplasty (gPK) and corneas of long-term soft contact lens wearers (cCL). METHODS: The study design was a consecutive cross-sectional trial. CCT was measured using rotating Scheimpflug camera (Pentacam, software version 1.16r04) in 80 cNHE, 79 cIOL, 46 gPK and 78 cCL. Analysis of variance (one-way ANOVA) was performed to compare differences of mean values between these four groups. Pearson's or Spearman's correlation coefficient (r) was determined between CCT value and age, follow up time after penetrating keratoplasty (timePK) or contact lens wearing time (timeCL). RESULTS: Means of CCT measurements were comparable between cNHE (mean CCT±standard deviation, 554±36μm), cIOL (551±40μm) and gPK (534±52μm) as determined by one-way ANOVA. Mean CCT values in cCL (537±37μm) were statistically significantly lower in comparison to cNHE (p=0.026, 95% CI=1.43-31.44). There was no linear correlation between age and CCT values of cNHE and cIOL (p=0.841, r=-0.031 and p=0.931, r=0.011, respectively). No linear relationship was determined between CCT values of cCL and timeCL (p=0.315, r=-0.125). CCT values of gPK did not correlate with timePK (p=0.738, r=0.054). CONCLUSIONS: The data reported here indicate that in the same statistical model among CCT values of cNHE, cIOL and gPK only long-term soft contact lenses (CL) wearer have significantly lower CCT measurements.
  Contact lens & anterior eye: the journal of the British Contact Lens Association 04/2013;
• Article: A silicone hydrogel contact lens after 7 years of continuous wear.

  Nilufer Yesilirmak, Dilek D Altınors
  [show abstract] [hide abstract]
  ABSTRACT: PURPOSE: To report an unusual case with a bandage silicone hydrogel lens that was applied over cyanoacrylate glue application for corneal perforation. DESIGN: Retrospective, interventional case report. METHODS: A 67-year-old woman with a history of corneal trauma experienced spontaneous corneal perforation in her left eye. Upon arrival, her anterior chamber was flat and Seidel test was positive. After initial treatment with cyanoacrylate adhesive and a bandage silicone hydrogel contact lens, there was no leakage and the anterior chamber was formed at the follow-up period. She was started topical antibiotics. RESULTS: After 7 years, she came back with the complaint of permanent redness in her left eye with the same silicone hydrogel lens in her eye. CONCLUSIONS: Corneal healing may occur under cyanoacrylate adhesive glue with therapeutic contact lenses and with proper antibiotic application. Silicone hydrogel contact lenses exhibit good efficacy and safety when utilized as a continuous wear therapeutic lens with antibiotics.
  Contact lens & anterior eye: the journal of the British Contact Lens Association 04/2013;
• Article: Successful treatment of phlyctenular keratoconjunctivitis with topical cyclosporin A.

  Olugbemisola Oworu, Pouya Alaghband, Colin Hutchinson
  Contact lens & anterior eye: the journal of the British Contact Lens Association 04/2013;
• Article: Evaluation of the ocular tolerance of a novel eyelid-warming device used for meibomian gland dysfunction.

  Christine Purslow
  [show abstract] [hide abstract]
  ABSTRACT: PURPOSE: Obstructive meibomian gland dysfunction (MGD) frequently induces a chronic complaint with various symptoms related to dry eye and discomfort. Previous research indicates a pivotal role for heat therapy for melting the meibum as part of any successful management plan, but delivery of constant temperature during treatment is vital. This study evaluated the performance of a novel device designed to deliver controlled, latent, moist heat to the eyelids and surrounding area. METHODS: The signs, symptoms and ocular temperature of 25 normal subjects (M8, F17; age 29.2±5.7 years) were recorded before and after a 10min application of the Blephasteam(®) device. Ocular temperature (non-invasive ocular thermography; A40 Flir, UK), tear film stability (NIBUT), intra-ocular pressure (IOP), and ocular surface staining and hyperaemia were recorded. Results were checked for normality and compared using paired t-tests. RESULTS: Temperatures in both eyelids were significantly greater after device application (upper +1.7±0.9°C; lower +2.1±0.7°C, p<0.0005). Bulbar conjunctival hyperaemia significantly decreased after treatment (p<0.005), but limbal and palpebral hyperaemia remained similar (p=0.33 and p=0.11, respectively). Ocular surface staining (p=0.74) and tear film stability (p=0.12) were unchanged in this normal cohort, and there was no significant change in IOP (13.8±2.0mmHg vs 12.9±2.2mmHg; p=0.092). CONCLUSIONS: The Blephasteam(®) device provides effective levels of warming that would be sufficient to melt meibum, and no adverse ocular responses were recorded in this cohort, indicating that this is a safe device. Interestingly, even in this normal cohort, ocular surface redness appears less after treatment.
  Contact lens & anterior eye: the journal of the British Contact Lens Association 04/2013;
• Article: Imaging meibomian glands on a patient with chalazia in the upper and lower lids: A case report.

  Sruthi Srinivasan, Kara L Menzies, Luigina Sorbara, Lyndon W Jones
  [show abstract] [hide abstract]
  ABSTRACT: AIM: To describe the meibomian gland (MG) appearance in a case of eyelid chalazia, using a novel meibography method. METHODS: A 29-year-old female of South Asian origin presented with mild swelling in the lower lid of the left eye. The patient also presented with a history of a recurrent chalazion in the upper lid of the same eye, which later progressed to an active chalazion. A chalazion also developed in the upper lid of the right eye. Meibography was performed using a novel Keratograph (Keratograph 4, OCULUS, Wetzlar, Germany) to evaluate the structure of the MG in the area affected by the chalazia. RESULTS: The area of the recurrent chalazion in the upper left lid showed partial and/or complete MG loss. The active chalazia in the lower left lid and the upper right lid showed inflammation and MG drop out at the affected site. The inflammation was found to be reduced during the follow-up visits, however disappearance of MG very specific to the region of the chalazion was observed. CONCLUSION: The Keratograph 4 was able to image the MG structures clearly, allowing the clinician to monitor the progression of chalazia and the MG loss in the affected areas.
  Contact lens & anterior eye: the journal of the British Contact Lens Association 03/2013;
• Article: Distribution of radii of curvature of anterior and posterior best fit sphere in a normal population: The Tehran Eye Study.

  Shiva Mehravaran, Hassan Hashemi, Mehdi Khabazkhoob, Akbar Fotouhi
  [show abstract] [hide abstract]
  ABSTRACT: PURPOSE: To determine the distribution and determinants of the radii of curvature of the anterior and posterior best fit spheres (ABFS and PBFS) of the cornea in a sample from the general normal population of Tehran. METHODS: A stratified random cluster sampling was used to select samples from the first 4 districts of Tehran proportionate to the population of each stratum. We examined the distribution of the ABFS and PBFS, as measured with the Orbscan II in different groups of age, sex, and refractive error, and determined their relationship with other variables by using both univariate and multiple regression analyses. Valid data was collected from 800 eyes, and analyses were done with data from 399 right eyes only. RESULTS: Mean ABFS and PBFS in the studied sample were 43.31±1.79D and 52.67±3.04D, respectively. ABFS increased with age while PBFS showed no significant association; both showed significant inter-sex differences. In the multiple linear regression model, both ABFS and PBFS significantly correlated directly with age and average keratometry, and inversely with corneal diameter; PBFS correlated directly with anterior chamber depth as well. Mean PBFS/ABFS ratio was 1.22±0.05 which significantly decreased with age and was significantly higher in females. CONCLUSION: Knowledge of normal ranges of ABFS and PBFS and their determinants, including age, mean keratometry, and corneal diameter, as well as the choice of measurement device, is necessary for comparing information from different populations and interpreting results.
  Contact lens & anterior eye: the journal of the British Contact Lens Association 03/2013;
• Article: Consensus on recording of gas permeable contact lens fit.

  James S Wolffsohn, Eef van der Worp, John de Brabander
  [show abstract] [hide abstract]
  ABSTRACT: PURPOSE: To develop a new schematic scheme for efficiently recording the key parameters of gas permeable contact lens (GP) fits based on current consensus. METHODS: Over 100 established GP fitters and educators met to discuss the parameters proposed in educational material for evaluating GP fit and concluded on the key parameters that should be recorded. The accuracy and variability of evaluating the fluorescein pattern of GP fit was determined by having 35 experienced contact lens practitioners from across the world, grading 5 images of a range of fits and the topographer simulation of the same fits, in random, order using the proposed scheme. The accuracy of the grading was compared to objective image analysis of the fluorescein intensity of the same images. RESULTS: The key information to record to adequately describe the fit of an GP was agreed as: the manufacturer, brand and lens parameters; settling time; comfort on a 5 point scale; centration; movement on blink on a ±2 scale; and the Primary Fluorescein Pattern in the central, mid-peripheral and edge regions of the lens averaged along the horizontal and vertical lens axes, on a ±2 scale. On average 50-60% of practitioners selected the median grade when subjectively rating fluorescein intensity and this was correlated to objective quantification (r=0.602, p<0.001). Objective grading suggesting horizontal median fluorescein intensity was generally symmetrical, as was the vertical meridian, but this was not the case for subjective grading. Simulated fluorescein patterns were subjectively and objectively graded as being less intense than real photographs (p<0.01). CONCLUSION: GP fit recording can be standardised and simplified to enhance GP practice.
  Contact lens & anterior eye: the journal of the British Contact Lens Association 03/2013;
• Article: Predicting success with silicone-hydrogel contact lenses in new wearers.

  Nigel Best, Laura Drury, James S Wolffsohn
  [show abstract] [hide abstract]
  ABSTRACT: PURPOSE: to evaluate changes in tear metrics and ocular signs induced by six months of silicone-hydrogel contact lens wear and the difference in baseline characteristics between those who successfully continued in contact lens wear compared to those that did not. METHODS: Non-invasive Keratograph, Tearscope and fluorescein tear break-up times (TBUTs), tear meniscus height, bulbar and limbal hyperaemia, lid-parallel conjunctival folds (LIPCOF), phenol red thread, fluorescein and lissamine-green staining, and lid wiper epitheliopathy were measured on 60 new contact lens wearers fitted with monthly silicone-hydrogels (average age 36±14 years, 40 females). Symptoms were evaluated by the Ocular Surface Disease Index (OSDI). After six months full time contact lens wear the above metrics were re-measured on those patients still in contact lens wear (n=33). The initial measurements were also compared between the group still wearing lenses after six months and those who had ceased lens wear (n=27). RESULTS: There were significant changes in tear meniscus height (p=0.031), bulbar hyperaemia (p=0.011), fluorescein TBUT (p=0.027), corneal (p=0.007) and conjunctival (p=0.009) staining, LIPCOF (p=0.011) and lid wiper epitheliopathy (p=0.002) after six months of silicone-hydrogel wear. Successful wearers had a higher non-invasive (17.0±8.2s vs 12.0±5.6s; p=0.001) and fluorescein (10.7±6.4s vs 7.5±4.7s; p=0.001) TBUT than drop-outs, although OSDI (cut-off 4.2) was also a strong predictor of success. CONCLUSION: Silicone-hydrogel lenses induced significant changes in the tear film and ocular surface as well as lid margin staining. Wettability of the ocular surface is the main factor affecting contact lens drop-out.
  Contact lens & anterior eye: the journal of the British Contact Lens Association 03/2013;
• Article: Observation of solution-induced corneal staining with fluorescein, rose bengal and lissamine green.

  Carole Maldonado-Codina, Michael L Read, Nathan Efron, Curtis B Dobson, Philip B Morgan
  Contact lens & anterior eye: the journal of the British Contact Lens Association 03/2013;
• Article: High myopia-partial reduction orthokeratology (HM-PRO): Study design.

  Jessie Charm, Pauline Cho
  [show abstract] [hide abstract]
  ABSTRACT: PURPOSE: To report the study design and preliminary results of a pilot study, High Myopia-Partial Reduction Orthokeratology study. METHODS: Children with myopia of 6.00D or above and who satisfied the recruitment criteria were randomly assigned to partial reduction orthokeratology (PR ortho-k) and spectacle-wearing control groups. The myopia of the PR ortho-k children were partially reduced using custom made 4-zone ortho-k lenses of target 4.00D. Residual refractive errors were corrected with single vision spectacles. Control subjects were fully corrected with single vision spectacles. PR ortho-k subjects were also required to return for assessment after the first overnight lens wear, and one week and one month after lens wear. RESULTS: Fifty-two eligible subjects were randomly assigned to PR ortho-k group (n=26) and control group (n=26). The median age of each group was 10.00 years. The median (range) subjective myopia of the right eye at baseline was 6.41D (5.00-8.00D) and 6.22D (6.00-8.00D) for PR ortho-k and spectacle groups, respectively (p>0.05). Nineteen (79%) PR ortho-k subjects achieved successful lens fit at the one month visit and the median myopic reduction was 3.75D in the right eye. The incidence of (mild) corneal staining in PR ortho-k subjects reduced from 30% at the first overnight lens wear to 16% at the 1-month visit. Corneal pigmented arc was observed in 32% of PR ortho-k subjects at the 1-month visit. CONCLUSIONS: PR ortho-k was successfully applied to high myopic children with no significant changes in ocular health/best corrected visual acuity after one month of lens wear.
  Contact lens & anterior eye: the journal of the British Contact Lens Association 03/2013;
• Article: Contribution of soft lenses of various powers to the optics of a piggy-back system on regular corneas.

  Langis Michaud, Daniel Brazeau, Marie-Eve Corbeil, Pierre Forcier, Pierre-Jean Bernard
  [show abstract] [hide abstract]
  ABSTRACT: PURPOSE: This study aims to report on the measured in vivo contribution of soft lenses of various powers to the optics of a piggyback system (PBS). METHODS: This prospective, non-dispensing clinical study was conducted on regular wearers of contact lenses who showed regular corneal profiles. Subjects were masked to the products used. The study involved the use of a spherical soft lens of three different powers in a PBS, used as a carrier for a rigid gas permeable lens. Baseline data were collected and soft lenses were then fitted on both eyes of each subject. Both lenses were assessed for position and movement. Over-refraction was obtained. Soft lens power contribution to the optics (SLPC) of a PBS system was estimated by computing initial ametropia, lacrymal lens, rigid lens powers and over-refraction. A set of data on one eye was kept, for each subject, for statistical analysis. RESULTS: Thirty subjects (12 males, 18 females), aged 24.4 (±4.5) years, were enrolled. The use of plus powered soft lenses enhanced initial RGP lens centration. Once optimal fit was achieved, all lenses showed normal movement. SLPC represented 21.3% of the initial soft lens power when using a -6.00 carrier, and 20.6% for a +6.00. A +0.50 did not contribute to any power induced in the system. These results are generally in accordance with theoretical model developed in the past. CONCLUSION: On average, except for the low-powered carrier, the use of a spherical soft lens provided 20.9% of its marked power. To achieve better results, the use of a plus-powered carrier is recommended.
  Contact lens & anterior eye: the journal of the British Contact Lens Association 03/2013;
• Article: Geographic and temporal risk factors for interruptions to soft contact lens wear in young wearers.

  Kathryn Richdale, Dawn Y Lam, G Lynn Mitchell, Robin L Chalmers, Meredith E Jansen, Beth T Kinoshita, Luigina Sorbara, Heidi Wagner
  [show abstract] [hide abstract]
  ABSTRACT: OBJECTIVES: This was a secondary analysis of an existing dataset of soft contact lens wearers age 8-33 years, who received eye care outside of a clinical trial. The aim was to identify geographical and temporal factors associated with interruptions to contact lens wear. METHODS: Data from six academic centers in North America captured 522 events in 3549 patients. Cases were analyzed overall and in subcategories of allergic, and serious and significant adverse events. General estimating equations were used to model the effect of geographic (Northwest, West, Central, Northeast, Southeast) and temporal (season, month, day of the week) factors, along with previously identified risk factors associated with interruptions in lens wear (patient age, contact lens material, overnight wear, lens care system, replacement schedule, and years of contact lens wear). RESULTS: After controlling for established risk factors, both region and temporal factors disrupted the patients' ability to maintain contact lens wear. About 4% of all visits had complications that led to an interruption in wear. Allergic events were highest in the Central region. Serious and significant adverse events peaked in the Southeast during the Autumn and Winter months (September, October, December). Day of the week was not significant in any model. CONCLUSIONS: This study provides evidence of seasonal and regional challenges to contact lens wear. As the use of soft contact lenses expands for both cosmetic and medical reasons, practitioners must examine ways to maintain continuous, safe, and healthy use of contact lenses across all patients.
  Contact lens & anterior eye: the journal of the British Contact Lens Association 03/2013;
• Article: Corneal epithelial permeability: Ethnic differences between Asians and non-Asians.

  Wing Y Li, Carol Hsiao, Andrew D Graham, Meng C Lin
  [show abstract] [hide abstract]
  ABSTRACT: PURPOSE: To ascertain whether a difference in the permeability of the corneal epithelium to fluorescein (Pdc) exists between Asians and non-Asians. METHODS: From a multi-study database we extracted 632 records of baseline, open-eye Pdc measurements taken on both eyes of 176 subjects. Subjects were awake for a minimum of 4h before measurement, and were free of ocular disease and central corneal staining. Pdc was transformed by natural logarithm to better approximate normality for statistical tests. RESULTS: The mean ln(Pdc) in the Asian group was significantly greater than in the non-Asian group [-2.34 ln(nm/s) vs. -2.58 ln(nm/s); p<0.001]. CONCLUSIONS: Compared with non-Asians, Asians exhibited a less negative ln(Pdc), which translates to a higher Pdc and a more permeable corneal epithelium. We speculate that this may be related to anatomic differences responsible for greater eyelid tension in Asians.
  Contact lens & anterior eye: the journal of the British Contact Lens Association 03/2013;