Contact Lens & Anterior Eye - Articles in Press

Effect of mild conjunctivitis complication on tear balance in dry eye - Corrected Proof

Hiroko Uchida, Yoshichika Imanaga — 2012-05-14

Abstract: Inflammation of the ocular surface influences the stability of tear fluid. Mild conjunctivitis is often associated with dry-eye patients. The effect of mild conjunctivitis complication on tear break-up time (BUT) in patients with dry eyes was investigated. A total of 93 patients with dry eyes, excluding those having moderate to severe conjunctivitis, atopic keratoconjunctivitis, vernal conjunctivitis, previous ocular surgery, or who use contact lenses, were divided into those with and without mild conjunctivitis, and the BUT was compared. Fifty-four cases were complicated by mild conjunctivitis, conjunctival papilla formation was observed in 40 of these, and the mean BUT was 3.54±1.02s. The mean BUT in 39 patients without conjunctivitis was 3.41±1.04s, showing no significant difference between the groups (p=0.56). Allergic conjunctivitis was frequently observed in patients with dry eyes, but the complication of mild conjunctivitis had no influence on BUT.

Clinical evaluation of the Oculus Keratograph - Corrected Proof

N. Best, L. Drury, J.S. Wolffsohn — 2012-04-30

Abstract: Aim: To determine the validity and reliability of the measurement of corneal curvature and non-invasive tear break-up time (NITBUT) measures using the Oculus Keratograph.Method: One hundred eyes of 100 patients had their corneal curvature assessed with the Keratograph and the Nidek ARKT TonorefII. NITBUT was then measured objectively with the Keratograph with Tear Film Scan software and subjectively with the Keeler Tearscope. The Keratograph measurements of corneal curvature and NITBUT were repeated to test reliability. The ocular sensitivity disease index questionnaire was completed to quantify ocular comfort.Results: The Keratograph consistently measured significantly flatter corneal curvatures than the ARKT (MSE difference: +1.83±0.44D), but was repeatable (p>0.05). Keratograph NITBUT measurements were significantly lower than observation using the Tearscope (by 12.35±7.45s; p<0.001) and decreased on subsequent measurement (by −1.64±6.03s; p<0.01). The Keratograph measures the first time the tears break up anywhere on the cornea with 63% of subjects having NITBUTs <5s and a further 22% having readings between 5 and 10s. The Tearscope results were found to correlate better with the patients symptoms (r=−0.32) compared to the Keratograph (r=−0.19).Conclusions: The Keratograph requires a calibration off-set to be comparable to other keratometry devices. Its current software detects very early tear film changes, recording significantly lower NITBUT values than conventional subjective assessment. Adjustments to instrumentation software have the potential to enhance the value of Keratograph objective measures in clinical practice.

Morphology of contact lens-induced conjunctival epithelial flaps: A pilot study - Corrected Proof

2012-04-16

Abstract: Purpose: Conjunctival epithelial flap (CEF) is a conjunctival condition most commonly seen in silicone hydrogel contact lens wearers. This study utilized impression cytology to investigate the cellular composition and health of CEFs.Methods: Nine (9) subjects were enrolled – 3 non-lens wearers, 3 contact lens wearers without CEF, and 3 contact lens wearers with CEFs wearing 8.4/13.8 lotrafilcon A lenses. Impression cytology samples were collected from the flap or similar locations, if CEF was absent, using rectangular 5mm×2mm Millipore HAWP02500 membrane filters. The filters were gently pressed onto the conjunctiva, subsequently fixed in 95% alcohol, stained with hematoxylin-eosin and evaluated under an Olympus IX70 microscope. Measurements of the longest cell and nucleus dimensions were measured on 40 cells from each filter by utilizing NIH Image 1.63.Results: CEF consisted of multilayers of epithelial and goblet cells and were devoid of inflammatory cells, basement membrane material and stromal tissue. The cytoplasmic and nuclear dimensions were similar within the groups and the cytoplasm-to-nucleus ratio was not different between the flap group and the non-lens wearing group.Conclusion: The CEF appeared to be formed by healthy epithelial and goblet cells that have been dislocated from their normal location along the conjunctival surface by the lens edge. No inflammatory cells were present in this contact lens induced condition, which is reported to be associated most commonly with the silicone hydrogel material.

Effects of aqueous polymeric surfactants on silicone-hydrogel soft- contact-lens wettability and bacterial adhesion of Pseudomonas aeruginosa - Corrected Proof

Victoria B. Tran, Ye Suel Sung, Kendra Copley, C.J. Radke — 2012-03-29

Abstract: Prevention of Pseudomonas aeruginosa binding to soft-contact lenses (SCLs) may curtail sight-threatening microbial keratitis. Substrate surface wettability is known to modulate adhesion of P. aeruginosa. This study investigates the use of aqueous alkoxylate block co-polymer surfactants for enhanced wettability and antibacterial adhesion of SCLs under leaching conditions. Specifically, Pluronic® F127 (PF) and three ethylene oxide-butylene oxide (EOBO) surfactants were studied with four commercially available silicone–hydrogel contact lenses: Pure Vision™, Acuvue Advance™, Acuvue Oasys™ and O2Optix™. Dilute aqueous PF and EOBO surfactants impregnated all four soft-contact lenses, as demonstrated by surface-tension decline for leached surfactant. For PF surfactant, significant surface-wettability improvement upon rinsing occurred only after overnight leaching. EOBO surfactant showed a similar pattern with O2Optix™ lenses. EOBO-pretreated Pure Vision™ lenses, however, showed fast leaching and a significant change in surface energy towards improved wettability. Adhesion assays of P. aeruginosa displayed a small decrease in the binding rate of PAK bacteria for EOBO-pretreated Pure Vision™ lenses, but not for EOBO-pretreated O2Optix™ lenses. P. aeruginosa strain-PAO1 bacteria adhesion to all lenses was independent of surface wettability. Despite the ability of polymeric surfactants to lower advancing contact angles under leaching conditions, increased lens wettability is not a universal panacea for antifouling of soft-contact lenses.

Fluid filled scleral contact lens in pediatric patients: Challenges and outcome - Corrected Proof

2012-03-29

Abstract: Purpose: To study the indications and the challenges while fitting scleral contact lens (ScCL) filled with fluid prior to lens insertion in pediatric patients.Methods: We retrospectively reviewed charts of patients of 16years or less who received ScCL (PROSE – Prosthetic Replacement of the Ocular Surface Ecosystem, Boston Foundation for Sight, Needham Heights, MA, USA) that were filled with fluid (Normal saline) before lens insertion during July 2006 to April 2010. The main goal of ScCL fitting was to improve vision in patients having keratoconus (KC) and improve the ocular microenvironment in ocular surface disease (OSD). Visual acuity before and after lens wear was noted.Results: Fluid-filled ScCL were dispensed to 15 patients (20 eyes). The indications for ScCL fitting were KC (n=3 eyes), Stevens Johnson syndrome (SJS, n=13 eyes), radiation keratopathy (n=1 eye), combined KC and SJS (n=1 eye) and KC and vernal keratoconjunctivitis (VKC, n=2 eyes). Mean age of the patients was 12.85years. The average daily lens wear was 9h. The vision improved by 2 lines or more in 85% and dropped by 2 lines or more in 45% eyes after 4h of lens wear due to tear debris collection. None of the patients had any complications. Patients were self sufficient inserting and removing ScCL. Two patients had broken lenses during the follow-up.Conclusions: ScCL are useful for pediatric patients who have OSD, irregular astigmatism or the two coexisting; KC combined with VKC or SJS, helping to maintain the health of the ocular surface and improves vision in these patients.

In vitro biocompatibility assessment of multipurpose contact lens solutions: Effects on human corneal epithelial viability and barrier function - Corrected Proof

M.E. Cavet, K.L. Harrington, K.R. VanDerMeid, K.W. Ward, J.-Z. Zhang — 2012-03-21

Abstract: Purpose: To explore the in vitro effects of multipurpose contact lens solutions (MPSs) on corneal epithelial barrier function and viability.Methods: Human corneal epithelial cells (HCEpiC) were exposed to 50% MPSs A–G. Viability was determined using metabolic activity, protease release and caspase assays. Barrier function was evaluated using immunostaining for the tight junction protein zonnula occludens-1 (ZO-1) and resistance measurements.Results: MPS A and G did not affect HCEpiC monolayer viability after 2h, while MPSs B–F significantly decreased viability. There was a significant decrease in stratified HCEpiC viability after exposure to MPSs B–E for 2h, while there was no effect of MPS A. After exposure of HCEpiC monolayers to MPS A, F or G for 30min, ZO-1 staining appeared similar to control. HCEpiC exposed to MPSs B and C demonstrated tight junction breakdown. There was no significant change in HCEpiC monolayer resistance after exposure to MPS A or F for 2h, while MPSs B–E and G reduced resistance. After exposure to MPS A–E, stratified HCEpiC resistance was significantly decreased after 2 or 4h. The decrease in resistance was significantly less with MPS A as compared to the other MPSs.Conclusions: MPSs caused varying modifications to cell viability and barrier function in monolayer and stratified HCEpiC. MPS A did not alter monolayer HCEpiC viability or barrier function, while MPSs B–G caused significant decreases of at least one parameter. Furthermore, MPS A had significantly less effect than MPSs B–E on viability and barrier function of stratified HCEpiC.

Kerasoft IC compared to Rose-K in the management of corneal ectasias - Corrected Proof

Fernando J. Fernandez-Velazquez — 2012-03-14

Abstract: Purpose: To determine the efficacy of the KeraSoft® IC (KIC) (Ultravision International Limited, Bedfordshire, UK), a silicone hydrogel contact lens, for the optical management of non-surgical corneal ectasias and to compare it with the Rose-K 2 RGP contact lens.Methods: In a retrospective study ninety-four eyes fitted with KIC (group A) were compared with seventy-seven eyes fitted with Rose-K® RGP lenses as a control group. Ocular diagnoses, corneal curvature by topography, refraction, best spectacle-corrected visual acuity (BSCVA), and age at time of fitting were noted. Outcome data included average daily wearing time, contact lens complications, visual acuity with the lens (BCLCVA), power of the lenses and length of follow-up.Results: Differences in either BCLCVA or wearing time could not be statistically established (p=0.63, p=0.15) between both groups. More biomicroscopic complications were found in the RGP group, basically corneal staining (P<0.0001). In the KIC group, BCLCVA was statistically similar between types of ectasia (p=0.19) as well as in mild and moderate keratoconus (p=0.45).Conclusions: KIC is a good alternative for the optical management of irregular corneal astigmatism in non surgical corneal ectasias such as keratoconus and pellucid marginal degeneration.

Clinical performance of an orthokeratology lens fitted with the aid of a computer software in Chinese children - Corrected Proof

Ka Yin Chan, Sin Wan Cheung, Pauline Cho — 2012-03-05

Abstract: Purpose: To report the clinical performance of the orthokeratology (ortho-k) lens fitted with computer assisted system after 1-month of lens wear, in a group of children undergoing ortho-k treatment in a 2-year randomized myopic control study.Method: Children aged 6–11 years old were fitted with the ortho-k lenses using computerized fitting. The initial myopia was 4.00–0.50D and the initial refractive astigmatism was within 1.25D. Lens performance, in terms of centration, myopic reduction, vision, ocular health status and lens binding incidence, was evaluated at one night, one week and one month after lens wear. Only data from the right eye was presented.Results: The initial spherical equivalent refraction (SER) for the 51 subjects was −2.29±0.81D. The first fit success rate was 90%. The reduction of SER after one night and one week aftercare visit were 57% and 81%, respectively. At the one month visit, the mean reduction in SER was 89% with unaided logMAR visual acuity of 0.03±0.11. Mild central corneal staining was found in 9–20% of the subjects at the aftercare visits. The incidences of lens binding at one night, one week and one month aftercare visits were 17%, 39% and 30%, respectively.Conclusions: Computer assisted system for Menicon Z Night lens fitting gave a high first fit success rate. Menicon Z Night lens was effective in myopic reduction and provided stable vision after one week of lens wear. Ocular health of the subjects after lens wear was generally unremarkable.

The role of heat in rubbing and massage-related corneal deformation - Corrected Proof

Charles W. McMonnies, Donald R. Korb, Caroline A. Blackie — 2012-02-10

Abstract: Purpose: To examine the role of elevated corneal temperature in the development of rubbing/massage-related corneal deformation and the possibility that warm compresses in the management of meibomian gland dysfunction or chalazion could contribute to such adverse responses.Methods: With reference to reports of corneal deformation associated with meibomian gland dysfunction, chalazion, dacryocystoceles and post-trabeculectomy, the mechanisms for increased corneal temperature due to ocular massage, especially when combined with warm compresses are examined.Results: Several mechanisms for rubbing/massage to elevate corneal temperature have been described, apart from the application of warm compresses or other forms of heat.Conclusions: Raised corneal temperature helps to explain corneal deformation which develops in association with rubbing or massage in conditions such as keratoconus, chalazion, post-trabeculectomy, post-laser assisted in situ keratomileusis, post-graft and dacryocystoceles. When combined with warm compresses or other methods of heat delivery to the eye, the elevation of corneal temperature appears to explain how meibomian gland dysfunction treatment involving warm compresses and massage could induce rubbing-related deformation. Patients whose management involves iatrogenic ocular massage appear to require screening for risk of corneal deformation. Risk may be increased for patients with a concurrent habit of rubbing their eyes abnormally in response to allergic itch for example. It appears to be possible to modify ocular massage techniques to reduce the risk of corneal deformation. Careful tutoring and follow-up using corneal topography appears to be required when massage is prescribed, especially when used in conjunction with heat application.