Corneal changes following short-term miniscleral contact lens wear

Purpose To examine the influence of short-term miniscleral contact lens wear on corneal shape, thickness and anterior surface aberrations. Methods Scheimpflug imaging was captured before, immediately following and 3 hours after a short period (3 hours) of miniscleral contact lens wear for 10 young (mean 27 ± 5 years), healthy participants. Natural diurnal variations were considered by measuring baseline diurnal changes obtained on a separate control day without contact lens wear. Results Small but significant anterior corneal flattening was observed immediately following lens removal (overall mean 0.02 ± 0.03 mm, p < 0.001) which returned to baseline levels three hours after lens removal. During the three hour recovery period significant corneal thinning (-13.4 ± 10.5 μm) and posterior surface flattening (0.03 ± 0.02 mm) were also observed (both p < 0.01). The magnitude of posterior corneal flattening during recovery correlated with the amount of corneal thinning (r = 0.69, p = 0.03). Central corneal clearance (maximum tear reservoir depth) was not associated with corneal swelling following lens removal (r = -0.24, p > 0.05). An increase in lower-order corneal astigmatism Z(2,2) was also observed following lens wear (mean -0.144 ± 0.075 μm, p = 0.02). Conclusions Flattening of the anterior corneal surface was observed immediately following lens wear, while ‘rebound’ thinning and flattening of the posterior surface was evident following the recovery period. Modern miniscleral contact lenses that vault the cornea may slightly influence corneal shape and power but do not induce clinically significant corneal oedema during short-term wear.

Donald Ezekiel AM : passionate and innovative contact lens practitioner and manufacturer

Donald Ezekiel (known to all as ‘Don’) was born in Singapore on September 12, 1936, to a German mother and Iraqi father. His parents were Jewish refugees, who met in Batavia,1 married and alternately lived in Batavia and Singapore. The family established their primary residence in Singapore after Don’s older brother Eric (later to become a haematologist) was born in 1934. The Ezekiel family was forced to flee in 1941 when the Japanese bombed Singapore and were fortunate to obtain passage on a hospital ship to Perth. They returned to Singapore after the war but left again on their own accord in 1951 due to race riots. The Ezekiels sold up everything in Singapore and decided to settle in Perth...

Transmittance properties of contact lens multipurpose solutions and their effects on a hydrogel lens

Purpose The aim was to assess the compatibility of different multipurpose solutions (MPSs) with one type of silicone hydrogel (SiH) contact lens by, assessing the changes in both ultraviolet (UV) and visible light transmissibility of the hydrogel lens caused by the MPSs. Methods The light transmittance from 200-700 nm were measured for the lotrafilcon B blister pack solution (BPS), six MPSs namely, ReNuMultiPlus Multi-Purpose Solution (Bausch and Lomb Inc., Rochester NY, USA.); Complete RevitaLens Multi-Purpose (Abbott Medical Optics Inc., Quarryvale Co. Dublin, Ireland); All In One Light (Sauflon Pharmaceuticals Ltd., Twickenham, England); SOLO-care AQUA™ (Ciba Vision Corporation Duluth, Georgia, USA.); Biomedics All-in-one solution (CooperVision, Hamble, UK); and HippiaMultiPlus All-in-one solution (Interojo Inc., Kyeonggi-do, Korea), and a lotrafilcon B SiH lens (before and after storage), using a spectrophotometer. Results The UV transmitted through the BPS and the MPS were similar (p >.05, for all), except for the HippiaMultiPlus which was lower (p < 0.001) by 19.8%. Mean transparency values were statistically (p<.001) significantly different between the BPS and the MPSs. All MP solution/SiH lens combinations resulted in relatively high UV transmittance values especially in the UVC spectrum, and significantly increased (p <.001) the visible light transmittance values of the SiH lens. Greater changes in transparency were observed in the ReNu/SiH lens (28.5%) and the Complete RevitaLens/SiH lens (24.9%) combinations. Conclusion The six MPSs showed significant variations in the transmitted UV and visible light. Similar to the BPS, all MPSs were equally transparent, but showed very poor UVA & UVB attenuation, except for the Hippia MultiPlus. The MPS/SiH lens combinations did not significantly affect the lens transparency but it significant increased the lens transmittance of UV radiation, after storage. Further in-vivo studies are needed to validate if this effect is constant.

Miniscleral lens wear influences corneal curvature and optics

Purpose Transient changes in corneal topography associated with soft and conventional or reverse geometry rigid contact lens wear have been well documented; however, only a few studies have examined the influence of scleral contact lens wear upon the cornea. Therefore, in this study, we examined the influence of modern miniscleral contact lenses, which land entirely on the sclera and overlying tissues, upon anterior corneal curvature and optics. Methods Anterior corneal topography and elevation data were acquired using Scheimpflug imaging (Pentacam HR, Oculus) immediately prior to and following 8 hours of miniscleral contact lens wear in 15 young healthy adults (mean age 22 ± 3 years, 8 East Asian, 7 Caucasian) with normal corneae. Corneal diurnal variations were accounted for using data collected on a dedicated measurement day without contact lens wear. Corneal clearance was quantified using an optical coherence tomographer (RS-3000, Nidek) following lens insertion and after 8 hours of lens wear. Results Although corneal clearance was maintained throughout the 8 hour lens wear period, significant corneal flattening (up to 0.08 ± 0.04 mm) was observed, primarily in the superior mid-peripheral cornea, which resulted in a slight increase in against-the-rule corneal astigmatism (mean +0.02/-0.15 x 94 for an 8 mm diameter). Higher order aberration terms of horizontal coma, vertical coma and spherical aberration all underwent significant changes for an 8 mm corneal diameter (p ≤ 0.01), which typically resulted in a decrease in RMS error values (mean change in total higher order RMS -0.035 ± 0.046 µm for an 8 mm diameter). There was no association between the magnitude of change in central or mid-peripheral corneal clearance during lens wear and the observed changes in corneal curvature (p > 0.05). However, Asian participants displayed a significantly greater reduction in corneal clearance (p = 0.04) and greater superior-nasal corneal flattening compared to Caucasians (p = 0.048). Conclusions Miniscleral contact lenses that vault the cornea induce significant changes in anterior corneal surface topography and higher order aberrations following 8 hours of lens wear. The region of greatest corneal flattening was observed in the superior-nasal mid-periphery, more so in Asian participants. Practitioners should be aware that corneal measurements obtained following miniscleral lens removal may mask underlying corneal steepening.

Hypoxic corneal changes following 8 hours of scleral contact lens wear

- Purpose To examine the change in corneal thickness and posterior curvature following 8 hours of miniscleral contact lens wear. - Methods Scheimpflug imaging (Pentacam HR, Oculus) was captured before, and immediately following, 8 hours of miniscleral contact lens wear for 15 young (mean age 22 ± 3 years), healthy participants with normal corneae. Natural diurnal variations were considered by measuring baseline corneal changes obtained on a separate control day without contact lens wear. - Results Over the central 6 mm of the cornea, a small, but highly statistically significant amount of edema was observed following 8 hours of miniscleral lens wear, after accounting for normal diurnal fluctuations (mean ± standard deviation percentage swelling 1.70 ± 0.98%, p < 0.0001). Posterior corneal topography remained stable following lens wear (-0.01 ± 0.07 mm steepening over the central 6 mm, p = 0.60). The magnitude of posterior corneal topographical changes following lens wear did not correlate with the extent of lens-related corneal edema (r = -0.16, p = 0.57). Similarly, the initial central corneal vault (maximum post-lens tear layer depth) was not associated with corneal swelling following lens removal (r = 0.27, p = 0.33). - Conclusions While a small amount of corneal swelling was induced following 8 hours of miniscleral lens wear (on average <2%), modern high Dk miniscleral contact lenses that vault the cornea do not induce clinically significant corneal edema or hypoxic related posterior corneal curvature changes during short-term wear. Longer-term studies of compromised eyes (e.g. corneal ectasia) are still required to inform the optimum lens and fitting characteristics for safe scleral lens wear to minimize corneal hypoxia.

International contact lens prescribing in 2014

Since the late 1990s, the International Contact Lens Prescribing Survey Consortium has prospectively gathered information about 285,000 contact lens fits from more than 50 countries. This article presents our 14th annual summary of current trends published in Contact Lens Spectrum. With only minor differences in the distribution of our surveys among markets, we have continued to adopt the same approach throughout the past 18 years. Through national coordinators, we approach contact lens prescribers in each country and ask them to record information about the first 10 patients whom they fit with contact lenses after receipt of our survey form. The information collected is generic, and respondents are weighted to reflect the volume of contact lens fits undertaken by each. For this 2014 report, we present information about 25,179 contact lens fits from 32 countries...

Contact lens citation metrics: The Spanish connection

To eye care practitioners, citation metrics may seem to be a somewhat esoteric and irrelevant concept, far removed from the realities or real world, day-to-day clinical practice. However, quantitative analysis of the published literature is becoming increasingly important, and a beautiful example of this is presented in this issue of the Journal of Optometry. My former PhD student, Genís Cardona, has teamed up with Joan Sanz to undertake a thorough and telling analysis of current worldwide publishing trends in the contact lens field. When held in the mirror, this work reflects the growing contributions from Spanish researchers to the field...

Contact lens prescribing trends 2015

Efron, Morgan and Woods share the findings of their latest annual survey of Australian contact lens prescribing habits.

International contact lens prescribing in 2015

We have been collecting data on worldwide contact lens prescribing habits for almost 20 years. Over this time period, we have amassed prospective information about 315,000 contact lens fits in 59 countries. This article marks our 15th report in Contact Lens Spectrum and features a breakdown of more than 23,000 contact lens fits in 34 markets. As in previous years, our international network of coordinators distributed survey forms to eyecare practitioners in their market who then recorded generic information about the first 10 patients fit with contact lenses after receipt. Information is gathered about patient age and gender; whether the contact lenses are prescribed as a new fit or a refit; contact lens material, design, and replacement frequency; number of intended days per week of use; wearing modality; and care system. Contact lens fits are weighted to reflect the number of fits undertaken by each eyecare practitioner. The study data were entered and processed at the University of Manchester and at the University of Waterloo.

Tissue compression following short-term miniscleral contact lens wear

To quantify regional (nasal, superior, temporal and inferior) and location specific (corneal and scleral) tissue compression following short-term miniscleral contact lens wear.

In vivo assessment of inflammatory cells in contact lens wearers

Dissatisfaction with, and discontinuation from, contact lens wear is a source of major frustration and inconvenience to users, and a problem that is thought to cost the contact lens industry hundreds of millions of dollars each year. By directly and non-invasively monitoring inflammatory cells in the tissues at the front of the eye in symptomatic and asymptomatic lens wearers, the candidate has been able to demonstrate an inflammatory basis for contact lens discomfort. This finding may pave the way towards the development of strategies to make contact lenses more safe and afford greater levels of comfort.