Influence of Cosmetic Color Tinted Contact Lenses on the Ocular Surface
Condition: Conjunctival Infections, Irritations and Inflammations; Hypertrophy; Conjunctiva; Corneal Pannus; Corneal Epithelial Wound
MeSH terms: Inflammation; Hypertrophy
Study type: Observational

Summary: 
      More than 1 million people worldwide wear soft contact lenses for refractive error
      correction. However, severe sight threatening complications due to contact lens wear such as
      contact lens-related microbial keratitis (CLMK) are about 1 per 2500 persons per year. The
      rate of infection increases drastically to 1 per 500 person per year if lenses were worn
      overnight. Recently, color tinted cosmetic soft contact lenses, which are essentially soft
      contact lenses with a color tinted annular ring, are gaining increasing popularity especially
      among the younger and Asian population desiring a change in iris color or the doll-eyed look.
      However, studies on the effect of these lenses on the ocular surface have been scarce.
      Recently, a report of 12 cases of lens-related microbial keratitis due to wear of the color
      tinted lenses have been reported. Others reported of decreased contrast sensitivity,
      increased higher order aberrations, and temporary changes in corneal topography due to color
      tinted lens wear. Nevertheless, comprehensive and prospective study has not yet been done.
      Thus, the purpose of this study is to conduct a prospective observational study to determine
      the influence of color tinted cosmetic contact lens wear both on visual performance and
      ocular surface alterations.
    

Detailed description: 
      3. Methods All subjects are required to fill out basic information and take a survey
      questionnaire before and after contact lens wear. Subjects will be examined and tested before
      being fitted to color tinted contact lens with slit-lamp biomicroscopy and fluorescein
      staining (Heig Strait, Germany), intraocular pressure measurement by pneumotonometery
      (Topcon® CT-80), refractometer (Topcon® KR-8900), uncorrected and best corrected Snellen
      visual acuity (UCVA and BCVA), Schirmir test 1, tear film break-up time (TBUT), corneal
      topography (Bausch & Lomb® Orb IIz), and endothelial cell density measurement by specular
      microscopy (Konan Noncon Robo-Sp-9000, USA). Exams are also performed at 1 week, 1, 3, and 6
      months of lens wear. A special chart for all subjects is filled out during each visit During
      each exam, subjects will be observed for signs of conjunctival injection, conjunctival
      papillary hypertrophy, pannus formation, and corneal epitheliopathy. These signs are graded
      as shown in the table below.

      Signs 0=Normal 1=Mild 2=Moderate 3=Severe Conjunctival Injection None Minimal Obvious Diffuse
      Papillae Size None <0.25mm 0.25-0.5mm >0.5mm Superficial Pannus No pannus 1 quadrant 2
      quadrants >=3 quadrants Punctate Epitheliopathy None <1/3 of cornea 1/3-1/2 of cornea
      Confluent or with epithelial defect

      Schirmir test 1 (basal secretion test) is performed for 5 minutes and considered abnormal if
      the filter strip wets <5 mm in length. TBUT of less than 10 seconds is considered abnormal.

      Impression cytology will be performed before lens wear and at 3 and 6 months post lens wear
      at National Taiwan University. Nitrocellulose filter paper with the pore size of 0.22 μm
      (Millipore GSWP 04700, Billerica, MA, U.S.A.) are cut into strips (about 4x8 mm). After a
      drop of topical anesthetic (proparacaine 0.5 %) application, excess tears are gently absorbed
      by sterile cotton swabs. Nitrocellulose strip are placed on the surface of limbal
      conjunctiva. After applying light pressure, the paper strips are peeled off and immediately
      fixed in 95% alcohol. The strips are then stained using periodic acid-Schiff (PAS ; Sigma
      395132, Hattiesburg, MS, USA) and examined under light microscopy at 40X magnification and
      graded by mask observers following Saini et al's criteria21 as follows. Grade 1: Small round
      epithelial cells with a nucleus to cytoplasm ration of 1:2. Large number of deeply positive
      cells present. A good confluent sheet of cells is usually obtained. Grade2: A good cell sheet
      consisting of larger polygonal epithelial cells with a decreased nucleocytoplasmic ration of
      1:3. Goblet cells reduced in number, but still deeply PAS-positive. Grade 3: Larger polygonal
      cells with a further decrease in nucleus to cytoplasm ratio. Reduced number of goblet cells,
      with reduced staining. Grade 4: Larger polygonal basophilic cells with pyknotic nuclei.
      Intracellular keratin often demonstrable. Absent goblet cells. Only a few loose clumps were
      obtainable. Goblet cell density is also graded by counting the average number of cells per
      100 epithelial cells in at least four high power fields (HPF). Grade 1: >30 goblet cells/ 4
      HPF. Grade 2: 15-30 goblet cells/ 4 HPF. Grade 3: 5-15 goblet cells/ 4 HPF. Grade 4: <5
      goblet cells/ 4 HPF.

      In vivo confocal microscopy imaging of the cornea will be performed before lens wear and at 3
      and 6 months post lens wear by one masked examiner on all subjects at National Taiwan
      University. One drop of 0.5% proparacaine solution and artificial tears was instilled
      immediately before each exam. After asking the patients to look straight ahead, an in vivo
      confocal microscope (Confoscan 3.4.1; Nidek Technologies, Padova, Italy) equipped with a
      standard 40x water-immersion front lens captured images of the full thickness of the central
      cornea automatically. Each examination took approximately 1 to 3 minutes and recorded 350
      images at a distance of 1.5 and 4 μm on the z-axis between successive images. During each
      visit, measurements were repeated with 4 um z-interval for 3 times followed by 1.5 um
      z-interval for 3 times. Analysis of epithelial cells morphology, epithelial thickness, and
      stromal reaction follows that has been published by Chen et al22-24. Corneal nerve morphology
      and density will also be recorded and analyzed.

      Used contact lenses will be place in the provided storage cases and brought back to check for
      completeness of lens with no tear or chipped pieces. The lenses are then used for further
      material analysis by scanning electromicroscopy (SEM) and bacterial adhesion determination
      with personal funding. For SEM, used lenses were fixed in half strength Karnovskys fixative (
      2% paraformaldehyde and 2.5% glutaraldehyde) after gentle washing. The fixative was removed
      and distilled water was added for rinsing. Rapid freezing with liquid nitrogen immersion was
      done before being placed under vacuum overnight. The concave side of samples was mounted on
      aluminum stubs and sputter-coated with gold for examination under SEM (JEOL Ltd, JSM 5300,
      Japan) at 15kV under various magnification. For bacterial adhesion determination, used lenses
      are collected in sterile plates and gently dipped three times in PBS before placement in
      eppendorf tubes containing 1ml PBS. The lenses are then macerated and serial dilutions up to
      105 are done before plating onto Muller-Hinton agar. The agar plates are incubated overnight
      and colony forming units are counted the next day. Number of colonies multiplied by dilution
      factor divided by the volume plated will give the CFU/ml/per contact lens.

      All data will be entered into Excel spreadsheet (Microsoft, Inc) and analyzed using SPSS
      software for Windows (11.0, SPSS, Inc.). Paired t-tests will be used to compare all
      parameters before and after wear of the color tinted contact lenses.
    

Intervention name(s): contact lens wear
Intervention type(s): Other
Intervention description(s): tinted contact lens wear
Other intervention name(s): cosmetic colored contact lenses; Ciba Vision Freshlook
Observational model: Cohort
Time perspective: Prospective
Sampling method: Probability Sample
Study population: 
        1) age 20-35 years old (2) myopia less than -6.00D and astigmatism less than -1.50D (3)
        previous soft contact lens wear discontinued for at least 2 weeks. Exclusion criteria
        includes: (1) subjects with previous Rigid Gas Permeable wear (2) any ocular inflammation
        or infection, dry eye syndrome, glaucoma, ocular trauma or surgery, and topical medication
        instillation (3) diabetic mellitus (4) pregnancy (5) any corneal disorders or dystrophies.
      
Keywords: conjunctival injection; conjunctival papillary hypertrophy; pannus formation; corneal epitheliopathy; Schirmer test; Impression cytology; confocal microscopy; Scanning electronmicroscopy (SEM); bacterial adhesion determination