Anterior chamber changes after suspending contact lens wear in keratoconus
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e10 Abstracts / Contact Lens & Anterior Eye 36 (2013) e1–e15 Method: Four different soft contact lens designs made from the same silicone hydrogel material were examined comprising of two lens edge designs (chiselled and knife edge) and two different lens mid-peripheral shape profiles. The 26 subjects aged 24.7 ± 4.6 years wore the plano lenses bilaterally in randomized order. On inser- tion and at 2 and 4 hours post-insertion, a cross-sectional image of the contact lens edge interaction with the ocular surface was cap- tured by a bespoke optical coherence tomographer and the lens en-face movement was simultaneously imaged with a high- speed, high-resolution camera at the 3, 6 and 9’o’clock lens edge positions. Optical imaging distortions were individually corrected for by com- pensating for the apparent distortion of a glass slide by the removed lens. Results: Epithelial thickness varied with edge position (p < 0.001). When corrected for distortion, epithelial indentation decreased with time after insertion (p = 0.010), varied with posi- tion on the lens edge (p < 0.001), changed after a blink (p < 0.001), but was unaffected by mid-peripheral shape profile or edge design. Horizontal and vertical lens movement did not change with time post-insertion, but were affected by mid-peripheral shape profile (p < 0.001) and edge design (p = 0.002 vertical only). Lens move- ment was associated with a thicker physiological epithelium under the lens and lens edge design. Conclusions: Soft contact lens movement and real ocular sur- face indentation is influenced by lens edge profile, making this a critical lens characteristic. OCT is a valuable new technology to enable the effect of lens design on fit and ocular physiology to be assessed. Session summary discussion. Eric Papas, Lauren Rogers. http://dx.doi.org/10.1016/j.clae.2013.08.039 Supportive data linking coefficient of friction and comfort Noel A. Brennan ∗ , Chantal Coles E-mail address: [email protected] (N.A. Brennan). Purpose: Previously, a strong correlation has been identified between a large collection of comfort data with two separate sets of coefficient of friction data (Brennan et al, OVS e-abstracts 90957 (2009) and 125603 (2012)). To verify the findings, a second set of comfort data was correlated with the larger source of friction data. Method: The staining grid of Andrasko provides comfort values after 2 hours of wear for a range of modern reusable contact lenses. Average comfort data across all solutions were used for each lens type. Coefficient of friction data was sourced from Roba et al (Tribol Lett, 2011). Water content, manufacturer stated oxygen transmissi- bility and modulus (French, Silicone-hydrogel website, 2007) were also entered in a multiple regression analysis to predict staining- grid comfort. Results: Eight lens materials were common to both the friction and comfort data. Co-efficicent of friction was highly correlated with comfort (R ˆ 2 = 0.91, p = 0.0002). Multiple regression analysis saw all of the other lens-related properties aside from coefficient of friction drop out. Conclusions: The 2-hour mean comfort data from the Staining Grid produce a remarkably similar outcome to the 30-day end-of- day median comfort data, with coefficient of friction showing the highest correlation and being the only variable remaining in the multiple regression analysis in both cases. This information is sup- portive of the hypothesis that friction is the principal determinant of comfort. However, there is also an apparent manufacturer influ- ence on comfort. For example, the three most comfortable lenses in the staining-grid comfort data are made by a single manufacturer. Thus, further research is required to rule out other manufacturer specific properties, such as lens edge design, or a combination of properties, as the major determinant of comfort. http://dx.doi.org/10.1016/j.clae.2013.08.040 Toric orthokeratology for slowing eye elongation (TO-SEE) study Connie Chen ∗ , Sin Wan Cheung, Pauline Cho E-mail address: [email protected] (C. Chen). Purpose: To evaluate the effectiveness of Menicon Z Night Toric orthokeratology (ortho-k) lens for correcting myopia and astigma- tism and myopic control. Method: A total of 80 subjects (aged 6 to 12 years) were enrolled (ortho-k: 43; control (single vision spectacles): 37), with-the-rule astigmatism of -1.25D or above and unremarkable ocular and gen- eral conditions were fitted with the Menicon Z Night Toric Lens (NKL Contactlenzen B.V., Emmen, The Netherlands). Visual acu- ity, subjective and objective refraction, corneal topography and biomicroscopy examination were performed at baseline, the first overnight, first week, first month aftercare visits and every 3 monthly thereafter for a duration of 2 years. Results: A total of 35 ortho-k and 23 control subjects completed the 2-year study. Toric ortho-k significantly reduced the manifest myopia from -2.46 ± 1.32 D to -0.37 ± 0.43 D and refractive astig- matism from -1.86 ± 0.64 D to -0.32 ± 0.34 D (p < 0.001, paired t test) after one month of lens wear. At the 24-month visit, the resid- ual myopia and astigmatism were -0.34 ± 0.47 D and -0.39 ± 0.37 D respectively. Mean ± SD logMAR visual acuity (VA) changed from 0.00 ± 0.07 (best corrected) at baseline to unaided visual acuity (UVA) 0.09 ± 0.12 at the 1-month visit and 0.08 ± 0.11 at the 24-month visit. Mean ± SD changes in axial length (AL) were 0.31 ± 0.27 and 0.64 ± 0.31 in ortho-k and control group, respectively. Subjects wearing ortho-k lenses had a slower increase in axial elongation by 52% compared with that of subjects wearing single-vision spectacles. Conclusions: Menicon Z Night Toric Lens is effective in cor- recting astigmatism and myopia in high myopic astigmats and the results from current study confirmed that toric design RGL was effective for myopic control in moderate to high astigmatic chil- dren. http://dx.doi.org/10.1016/j.clae.2013.08.041 Anterior chamber changes after suspending contact lens wear in keratoconus Clare O’Donnell ∗ , Amit Navin Jinabhai, Cindy Tromans, Radhakrishnan Hema E-mail address: [email protected] (C. O’Donnell). Purpose: This study reports on changes in anterior chamber (AC) parameters after suspending RGP (rigid gas- permeable) con- tact lens wear for one week in 16 patients with moderate to severe keratoconus. Possible alterations in corneal profile parame- ters were also explored. Method: The AC structural parameters and corneal profile were evaluated using Scheimpflug photography (Oculus Pentacam) per- formed at two visits seven days apart, after patients had removed their habitual RGP contact lenses. Subjects were instructed to wear their lenses for 4 hours prior to the first visit. Results: Significant increases in the inferior (p = 0.001) and temporal AC angles (p = 0004), AC depth (p = 0.00013), AC vol- ume (p = 0.00011) and the mean central keratometric reading were
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Transcript of Anterior chamber changes after suspending contact lens wear in keratoconus
e10 Abstracts / Contact Lens & Anterior Eye 36 (2013) e1–e15
Method: Four different soft contact lens designs made from thesame silicone hydrogel material were examined comprising of twolens edge designs (chiselled and knife edge) and two different lensmid-peripheral shape profiles. The 26 subjects aged 24.7 ± 4.6 yearswore the plano lenses bilaterally in randomized order. On inser-tion and at 2 and 4 hours post-insertion, a cross-sectional image ofthe contact lens edge interaction with the ocular surface was cap-tured by a bespoke optical coherence tomographer and the lensen-face movement was simultaneously imaged with a high- speed,high-resolution camera at the 3, 6 and 9’o’clock lens edge positions.Optical imaging distortions were individually corrected for by com-pensating for the apparent distortion of a glass slide by the removedlens.
Results: Epithelial thickness varied with edge position(p < 0.001). When corrected for distortion, epithelial indentationdecreased with time after insertion (p = 0.010), varied with posi-tion on the lens edge (p < 0.001), changed after a blink (p < 0.001),but was unaffected by mid-peripheral shape profile or edge design.Horizontal and vertical lens movement did not change with timepost-insertion, but were affected by mid-peripheral shape profile(p < 0.001) and edge design (p = 0.002 vertical only). Lens move-ment was associated with a thicker physiological epithelium underthe lens and lens edge design.
Conclusions: Soft contact lens movement and real ocular sur-face indentation is influenced by lens edge profile, making this acritical lens characteristic. OCT is a valuable new technology toenable the effect of lens design on fit and ocular physiology to beassessed.
�Session summary discussion.��Eric Papas, Lauren Rogers.
http://dx.doi.org/10.1016/j.clae.2013.08.039
Supportive data linking coefficient of frictionand comfort
Noel A. Brennan ∗, Chantal ColesE-mail address: [email protected] (N.A. Brennan).
Purpose: Previously, a strong correlation has been identifiedbetween a large collection of comfort data with two separate setsof coefficient of friction data (Brennan et al, OVS e-abstracts 90957(2009) and 125603 (2012)). To verify the findings, a second set ofcomfort data was correlated with the larger source of friction data.
Method: The staining grid of Andrasko provides comfort valuesafter 2 hours of wear for a range of modern reusable contact lenses.Average comfort data across all solutions were used for each lenstype. Coefficient of friction data was sourced from Roba et al (TribolLett, 2011). Water content, manufacturer stated oxygen transmissi-bility and modulus (French, Silicone-hydrogel website, 2007) werealso entered in a multiple regression analysis to predict staining-grid comfort.
Results: Eight lens materials were common to both the frictionand comfort data. Co-efficicent of friction was highly correlatedwith comfort (R2̂ = 0.91, p = 0.0002). Multiple regression analysissaw all of the other lens-related properties aside from coefficientof friction drop out.
Conclusions: The 2-hour mean comfort data from the StainingGrid produce a remarkably similar outcome to the 30-day end-of-day median comfort data, with coefficient of friction showing thehighest correlation and being the only variable remaining in themultiple regression analysis in both cases. This information is sup-portive of the hypothesis that friction is the principal determinantof comfort. However, there is also an apparent manufacturer influ-ence on comfort. For example, the three most comfortable lenses inthe staining-grid comfort data are made by a single manufacturer.
Thus, further research is required to rule out other manufacturerspecific properties, such as lens edge design, or a combination ofproperties, as the major determinant of comfort.
http://dx.doi.org/10.1016/j.clae.2013.08.040
Toric orthokeratology for slowing eyeelongation (TO-SEE) study
Connie Chen ∗, Sin Wan Cheung, Pauline ChoE-mail address: [email protected] (C. Chen).
Purpose: To evaluate the effectiveness of Menicon Z Night Toricorthokeratology (ortho-k) lens for correcting myopia and astigma-tism and myopic control.
Method: A total of 80 subjects (aged 6 to 12 years) were enrolled(ortho-k: 43; control (single vision spectacles): 37), with-the-ruleastigmatism of -1.25D or above and unremarkable ocular and gen-eral conditions were fitted with the Menicon Z Night Toric Lens(NKL Contactlenzen B.V., Emmen, The Netherlands). Visual acu-ity, subjective and objective refraction, corneal topography andbiomicroscopy examination were performed at baseline, the firstovernight, first week, first month aftercare visits and every 3monthly thereafter for a duration of 2 years.
Results: A total of 35 ortho-k and 23 control subjects completedthe 2-year study. Toric ortho-k significantly reduced the manifestmyopia from -2.46 ± 1.32 D to -0.37 ± 0.43 D and refractive astig-matism from -1.86 ± 0.64 D to -0.32 ± 0.34 D (p < 0.001, paired ttest) after one month of lens wear. At the 24-month visit, the resid-ual myopia and astigmatism were -0.34 ± 0.47 D and -0.39 ± 0.37D respectively. Mean ± SD logMAR visual acuity (VA) changed from0.00 ± 0.07 (best corrected) at baseline to unaided visual acuity(UVA) 0.09 ± 0.12 at the 1-month visit and 0.08
± 0.11 at the 24-month visit. Mean ± SD changes in axial length(AL) were 0.31 ± 0.27 and 0.64 ± 0.31 in ortho-k and control group,respectively. Subjects wearing ortho-k lenses had a slower increasein axial elongation by 52% compared with that of subjects wearingsingle-vision spectacles.
Conclusions: Menicon Z Night Toric Lens is effective in cor-recting astigmatism and myopia in high myopic astigmats and theresults from current study confirmed that toric design RGL waseffective for myopic control in moderate to high astigmatic chil-dren.
http://dx.doi.org/10.1016/j.clae.2013.08.041
Anterior chamber changes after suspendingcontact lens wear in keratoconus
Clare O’Donnell ∗, Amit Navin Jinabhai, CindyTromans, Radhakrishnan HemaE-mail address: [email protected] (C. O’Donnell).
Purpose: This study reports on changes in anterior chamber(AC) parameters after suspending RGP (rigid gas- permeable) con-tact lens wear for one week in 16 patients with moderate tosevere keratoconus. Possible alterations in corneal profile parame-ters were also explored.
Method: The AC structural parameters and corneal profile wereevaluated using Scheimpflug photography (Oculus Pentacam) per-formed at two visits seven days apart, after patients had removedtheir habitual RGP contact lenses. Subjects were instructed to weartheir lenses for 4 hours prior to the first visit.
Results: Significant increases in the inferior (p = 0.001) andtemporal AC angles (p = 0004), AC depth (p = 0.00013), AC vol-ume (p = 0.00011) and the mean central keratometric reading were
Abstracts / Contact Lens & Anterior Eye 36 (2013) e1–e15 e11
found (p = 0.001) after lens wear was suspended. Simultaneousreductions in corneal volume (p = 0.000004), central corneal thick-ness (p = 0.0001) and a negative shift in anterior surface cornealasphericity (p = 0.002) were also observed between the two visits.
Conclusions: Suspending RGP contact lens wear results in alter-ations to the AC structural parameters and corneal profile inpatients with keratoconus.
http://dx.doi.org/10.1016/j.clae.2013.08.042
And it was all going so well! Dealing withcomplications in contact lens wear
Eric PapasE-mail address: [email protected].
Contact lens wear can be associated with a wide range of com-plications ranging from corneal infection to papillary changes tothe eyelid. Both the prevalence and severity of these conditionsvary widely. Potential consequences in the most severe cases can bepermanent loss of vision while discomfort, redness and cessation ofwear frequently occur. It is important therefore that practitionersare able to recognise each potential condition and be in a posi-tion to take the appropriate action in terms of management andpatient counselling. This presentation will explore the features ofinfectious, inflammatory, mechanically and chemically related con-ditions occurring during contact lens wear. In addition to learninghow to recognize and differentiate these events, attendees will alsobe introduced to the aetiological factors responsible and be givenguidance on management approaches.
http://dx.doi.org/10.1016/j.clae.2013.08.043
Astigmatism and soft torics–the challenge or isit?”
Anna SulleyE-mail address: [email protected].
Despite recent advances in toric soft contact lens offerings, theirusage remains lower than the prevalence of astigmatism. So whatare the impediments to patients being fitted with these lenses? Thispresentation will provide recent insights into potential obstaclesfrom patients and practitioners in toric lens usage, and highlightways to improve patient education and communication. Latestresearch regarding toric soft lens designs will be reviewed, withinnovative assessment techniques that have improved our under-standing of toric lens orientation and have led to more successfuldesigns, including the effects of lid interaction, eye movements andgravity on toric soft lens performance. Techniques which can beimplemented in the consulting room to assess toric lens perfor-mance will be discussed, along with fitting tips to improve successrates and enhance patient satisfaction.
http://dx.doi.org/10.1016/j.clae.2013.08.044
Rigid lenses, do they have a place in moderncontact lens practice and how do I fit them?
Judith MorrisE-mail address: [email protected].
The lecture will try to explain that RGP fitting is a less difficultoption for your patients than you might think. It will describe thesteps to use for the choice of lens and design; but more importantlywill highlight the aspects of the fluorescein patterns that need tobe considered. The outcome should be that you feel more confident
when seeing your next potential RGP fitting, as some people willcertainly benefit from their use.
http://dx.doi.org/10.1016/j.clae.2013.08.045
Contact lenses–what to expect in your pre- regyear
Sheetal PatelE-mail address: she [email protected].
After successfully completing a degree in Optometry, the onlyobstacle that remains in your path to becoming a qualifiedoptometrist is the pre–registration year (scheme for registration).
This presentation will give an overview of the scheme for regis-tration and the tools that can be put in place to help it run smoothly.Emphasis will be placed on the contact lens competencies that needto be achieved throughout the year. The presentation will also lookat the importance of this contact lens experience and how it willbe invaluable once you qualify.
http://dx.doi.org/10.1016/j.clae.2013.08.046
RGP WORKSHOP–pre registered delegates onlyGet a head start on your pre-reg at the BCLA RGPfitting workshop
Caroline Burnett Hodd ∗, Iain MayE-mail address: [email protected] (C.B. Hodd).
Many pre-registration optometrists say that the RGP fittingcompetencies are the ones they lose the most sleep over. Here isyour chance to get ahead of the game and begin your pre-reg con-fident in RGP fitting by attending the BCLA RGP fitting workshop.
The workshop is completely hands on and you will learn howto insert and remove RGP lenses, how to assess and modify the fit,how to order a lens, how to advise on materials and solutions andwhat to do when things go wrong!
This International Session has been specifically designed toprovide the latest research findings on the use of contact lensesand solutions worldwide. A key component is latest informationon the compliant (and non-compliant) use of lenses and solutionsin different markets. New studies of behaviours in this area will bepresented for the first time at a major conference. This informationwill allow optometrists and contact lens opticians to better evaluatethe lens care behaviours of their patients and improve complianceand as such, reduce the likelihood of contact lens-associated infec-tions and inflammations.
The session will also showcase different forms of contact lenspractice form around the world. There is clear evidence that con-tact lens practitioners in markets such as Japan, Australia, Korea,France and the Netherlands (amongst others) offer significantly dif-ferent types of contact lens materials, designs and modalities. Thissession will explore these differences in depth, with expert repre-sentatives from each market. This information will lead to examplesof prescribing patterns and insights which could be employed in thepractices of the audience members, to the benefit of patients.
http://dx.doi.org/10.1016/j.clae.2013.08.047
