CLEAR - Evidence-based contact lens practice

Development and Initial Validation of the MCL-PRO-CAT: A computerized adaptive test designed to measure multifocal contact lens performance from the patient's perspective

PURPOSE

To create a valid and reliable computer-adaptive testing (CAT) tool for assessing Multifocal Contact Lens (MCL) performance in presbyopic individuals, ensuring high precision. The self-administered tool will initially be accessible online in Spanish.

METHODS

Five steps were followed for the correct development of the instruments: item bank development, item refinement phase, item response theory calibration of the refined item bank, CAT simulations and design, and an initial validation study. A total of 1163 presbyopic patients were involved in the over-all study. Convergent validity was assessed by comparing results to the CLDQ-8 questionnaire, and repeatability assessment was performed two weeks after the initial completion.

RESULTS

The final item bank consisted of 108 items assessing various relevant domains for MCL performance evaluation. The calibration study showed a person separation index of 4.69 and a reliability of 0.96 along with a measurement precision of 0.27. The final CAT distinguished between 16 levels of MCL performance by presenting an average of 10.61  ± 1.00 items per patient, with an average completion time of 3:04 ± 1:24 min. Signs of convergent validity showed a correlation of 0.73 and repeatability was assessed showing an intraclass Correlation Coefficient of 0.881 with a 95% Confidence Interval 0,815-0,924, and Limits of Agreement of  ± 1.07.

CONCLUSION

The MCL-PRO-CAT is a groundbreaking tool for evaluating MCL performance in presbyopic individuals. With automated scoring and fewer items, it was feasible, valid, and precise, enhancing clinical practicality.

Changing the paradigm of soft contact lens fitting: A sagittal height-based approach

OBJECTIVE

The present study evaluated the correlation between ocular sagittal height and lens sagittal depth, specifically focusing on the sagittal difference (δ-sag) that defines an optimal lens fit.

METHODS

The ocular sagittal height (spanning a 14.2-mm chord in the ocular surface flattest meridian) of 30 subjects was measured using the Oculus Pentacam HR. Participants were fitted with eight different standard daily disposable soft contact lenses, each having a known sagittal depth. To evaluate the fit, both objective methods (using ImageJ software) and subjective assessments (by two experienced eye care professionals [ECPs]) were employed. Descriptive statistics were obtained for different δ-sag, and correlations and a regression model were applied to determine the δ-sag range indicative of a satisfactory lens fit, based on the objective and subjective evaluations.

RESULTS

The δ-sag achieved in most cases ranged between 200 and 600 μm. Participants reported high comfort levels independently of δ-sag (H = 8.99; p = 0.25) and type of contact lens (χ2 = 1.47; p = 0.98). Significant correlations were found between δ-sag and objective assessments of lens centration (inferior, nasal and temporal) and movement (nasal lag). The regression model, based on the subjective assessment conducted by the ECPs, yielded a δ-sag of between 120 and 280 μm for a score considered as good.

CONCLUSIONS

Objective and subjective assessments showed significant associations with δ-sag. A standard cast-moulded disposable soft contact lens whose sagittal depth exceeded the ocular sagitta corresponding to the chord equivalent to the total contact lens diameter by 120-280 μm would most likely result in an optimal fit. These findings could help improve fitting accuracy and reduce dropout rates, thereby enhancing patient experience and ocular health.

Short-Term Effects of Various Contact Lenses on Accommodative Function in Myopic Children

PURPOSE

To assess the short-term impact of different types of contact lenses on accommodation in the same group of myopic children compared with single-vision spectacle lenses.

METHODS

Thirty myopic children aged 10.2 ± 1.5 years were enrolled. Each participant was corrected with four different modalities in following sequence: single-vision spectacles (SVSP), single-vision soft contact lens (SVSCL), a high-addition multifocal soft contact lens (MFSCL), and orthokeratology lenses (OKL). Measurements included the dynamic accommodative stimulus-response curve (ASRC), distance accommodative facility (DAF), negative relative accommodation (NRA), and positive relative accommodation (PRA). Repeated-measures analysis of variance with Bonferroni correction was performed.

RESULTS

The accommodative parameters differed among the four modalities except for the slope of ASRC ( F = 1.700, P = 0.173). Single-vision spectacle lens exhibited the highest accommodative lag area (10.08 ± 1.65 D 2 ) and the lowest objective accommodative amplitude (7.72 ± 0.93 D) and PRA (-2.51 ± 0.62 D) (all P < 0.05). Multifocal soft contact lens, OKL, and SVSCL showed no significant differences in accommodative lag area (8.93 ± 1.78, 7.98 ± 2.33, 8.44 ± 2.20 D 2 ), NRA (2.23 ± 0.33, 2.23 ± 0.38, 2.39 ± 0.33 D), PRA (-3.05 ± 0.78, -3.43 ± 1.05, 3.00 ± 1.02 D), or DAF (23.8 ± 6.99, 26.0 ± 8.23, 23.3 ± 7.07 D); however, OKL (8.68 ± 1.08 D) induced greater objective accommodative amplitude than SVSCL (8.26 ± 0.97 D) ( P = 0.010).

CONCLUSIONS

Single-vision spectacles exhibited worse accommodative function than the other three modalities. However, no significant changes in accommodation were detected when using OKL or high-addition MFSCL compared with SVSCL, except higher objective accommodative amplitude with OKL than SVSCL.

New developments in optometric training in the United Kingdom

With optometrists well placed to address the challenges and opportunities faced by contemporary eye care systems, it is ever more important to understand the genesis and development of the profession, so that optometrists can continue to build on this legacy for patient benefit. While the optometry profession of optometry in the United Kingdom can arguably trace its foundation back to 1629 and the Royal Charter gifted by Charles I to the Worshipful Company of Spectacle Makers to establish the 60th Livery Company of the City of London, the genesis of optometry as an independent profession (initially known as 'ophthalmic optics') can perhaps best be attributed to the formation of the British Optical Association in 1895. This paper reviews the current legal framework and recent changes that dictates how the optometry profession are trained and practice, along with clinical and educational innovations that are shaping the future role of the profession.

The Impact of Comfort Eluting Agents and Replacement Frequency on Enhancing Contact Lens Performance

This review explores the development and clinical implications of soft contact lenses designed to elute comfort agents, emphasizing their role in enhancing user experience and ocular health. As discomfort remains one of the primary reasons for discontinuation of lens wear, this concept aims to address this challenge by gradually releasing these agents over their period of use. This review also explores the effectiveness, safety, and user satisfaction associated with frequent replacement schedules of these lenses. Clinical trials demonstrate that lenses with eluting comfort agents significantly reduce dryness and irritation, leading to improved wear-time and overall comfort. The findings suggest that frequent replacement not only enhances lens hygiene but also maximizes the therapeutic benefits of the eluted agents, promoting a healthier ocular environment. The implications for practice highlight a shift towards more patient-centered approaches in contact lens design and management, aiming to improve adherence and satisfaction among users. This research paves the way for future innovations in contact lens technology, focusing on personalized solutions that cater to individual comfort needs.

Lid wiper epitheliopathy: Topical review of current identification strategies and future perspectives

Lid Wiper Epitheliopathy (LWE) is a recognized ocular condition affecting visual quality and ocular comfort, characterized by the damage of the marginal conjunctiva of the upper eyelid. This review critically examines the current strategies for LWE identification and explores the multifactorial etiology of LWE and its association with various ocular surface diseases. A literature review conducted on PubMed identified 67 relevant studies, which were analyzed to enhance understanding of LWE's diagnostic criteria and its clinical implications, offering future perspectives on improving diagnostic accuracy and patient outcomes. The association between LWE and contact lens-related discomfort is examined, with studies reporting conflicting findings regarding its prevalence and severity among soft contact lens wearers. Moreover, LWE has been linked to tear film abnormalities, altered tear composition, and eyelid margin abnormalities in non-contact lens wearers, further complicating diagnosis and management. Current LWE grading systems, including subjective methods and semi-objective approaches, are reviewed, highlighting challenges such as subjectivity, complexity, and variability. Recent advances in LWE grading, including semi-automated methods and photographic scales, show promise but face implementation challenges in clinical settings. The review concludes by proposing areas for further research, including investigating factors contributing to LWE onset and development, developing more sensitive diagnostic tools, and exploring the impact of LWE on ocular surface health and visual function. Standardization, validation, and innovation in grading systems are emphasized to enhance diagnostic accuracy and improve clinical outcomes for patients with LWE. Ongoing research in LWE grading is essential for addressing diagnostic challenges and optimizing assessment methodologies in clinical practice.

Hand-Washing Habits in a Sample of Spanish Soft Contact Lens Wearers

Contact lens (CL) wear is a safe method for the correction of refractive errors. However, rare, severe ocular complications may occur which may lead to visual loss. As most of these complications are related to poor patient compliance with care and maintenance instructions, resulting in the contamination of hands, CLs and accessories, it was the purpose of this study to assess hand-washing habits in a sample of Spanish soft CL wearers. Hand hygiene was explored through a self-reported online survey and via an in-office practical demonstration in a subset of those users answering the survey. A total of 198 surveys were analyzed, and 18 CL users participated in the practical demonstration. Overall, hand-washing habits were not adequate, with 35 (17.8%) and 103 (52.2%) participants reporting not always washing their hands prior to CL or storage case manipulation, respectively. While 161 (81.3%) participants dried their hands after washing, 132 of these (82.1%) used non-disposable cloth towels. Participants receiving specific hand-washing information from their practitioners (141, or 71.1%) had better hand hygiene (p < 0.05). During the practical demonstration, 13 (72.2%) participants used water and soap to wash their hands, but only 3 (16.7%) displayed correct hand washing routines. Complete patient education, as well as practical reminders at all follow-up visits, are essential to ensure better hand hygiene in order to reduce the probability of ocular complications and to guarantee safe and satisfactory CL use.

BCLA CLEAR Presbyopia: Epidemiology and impact

The global all-ages prevalence of epidemiologically-measured 'functional' presbyopia was estimated at 24.9% in 2015, affecting 1.8 billion people. This prevalence was projected to stabilise at 24.1% in 2030 due to increasing myopia, but to affect more people (2.1 billion) due to population dynamics. Factors affecting the prevalence of presbyopia include age, geographic location, urban versus rural location, sex, and, to a lesser extent, socioeconomic status, literacy and education, health literacy and inequality. Risk factors for early onset of presbyopia included environmental factors, nutrition, near demands, refractive error, accommodative dysfunction, medications, certain health conditions and sleep. Presbyopia was found to impact on quality-of-life, in particular quality of vision, labour force participation, work productivity and financial burden, mental health, social wellbeing and physical health. Current understanding makes it clear that presbyopia is a very common age-related condition that has significant impacts on both patient-reported outcome measures and economics. However, there are complexities in defining presbyopia for epidemiological and impact studies. Standardisation of definitions will assist future synthesis, pattern analysis and sense-making between studies.

BCLA CLEAR Presbyopia: Management with contact lenses and spectacles

This paper seeks to outline the history, market situation, clinical management and product performance related to the correction of presbyopia with both contact lenses and spectacles. The history of the development of various optical forms of presbyopic correction are reviewed, and an overview is presented of the current market status of contact lenses and spectacles. Clinical considerations in the fitting and aftercare of presbyopic contact lens and spectacle lens wearers are presented, with general recommendations for best practice. Current options for contact lens correction of presbyopia include soft simultaneous, rigid translating and rigid simultaneous designs, in addition to monovision. Spectacle options include single vision lenses, bifocal lenses and a range of progressive addition lenses. The comparative performance of both contact lens and spectacle lens options is presented. With a significant proportion of the global population now being presbyopic, this overview is particularly timely and is designed to act as a guide for researchers, industry and eyecare practitioners alike.

Simulation of daily soft multifocal contact lenses using SimVis Gekko: from in-vitro and computational characterization to clinical validation

Multifocal contact lenses (MCLs) are one of the solutions to correct presbyopia, but their adoption is not widespread. To address this situation, visual simulators can be used to refine the adaptation process. This study aims to obtain accurate simulations for a visual simulator (SimVis Gekko; 2EyesVision) of daily soft MCL designs from four manufacturers. In-vitro characterization of these MCLs-several powers and additions- was obtained using NIMO TR-1504. From the averaged relative power profiles across powers, phase maps were reconstructed and the Through-Focus Visual Strehl metric was calculated for each MCL design. The SimVis Gekko simulation corresponding to each MCL design was obtained computationally and bench-validated. Finally, the MCL simulations were clinically validated involving presbyopic patients. The clinical validation results show a good agreement between the SimVis Gekko simulations and the real MCLs for through-focus visual acuity (TF-VA) curves and VA at three real distances. All MCL designs showed a partial correlation higher than 0.90 and a Root Mean Square Error below 0.07 logMAR between the TF-VA of simulations and Real MCLs across subjects. The validity of the simulation approach using SimVis Gekko and in-vitro measurements was confirmed in this study, opening the possibility to accelerate the adaptation of MCLs.

Multifocal contact lens success predictability

PURPOSE

The current multi-study analysis combined data from three studies to quantify the relationship between the initial reaction to soft multifocal contact lens (MFCL) design types at dispensing and evaluate the predictability of overall vision satisfaction (OVS) and intention to purchase (ITP) after 1 week of wear.

METHOD

Three prospective studies tested MFCLs over 1-week of wear following the same protocol, using a range of potentially predictive ratings at dispensing, and both OVS and ITP at 1-week as an indicator acceptance level. In each study, two of MyDay® multifocal, clariti® 1 day multifocal, Biofinity® multifocal (worn as a daily disposable lens) or 1 DAY ACUVUE® MOIST MULTIFOCAL were dispensed for 1-week of daily wear. OVS was recorded on a 100-point VAS and ITP on a 5-point LIKERT scale. Fourteen possible predictors were entered in the statistical model, and predictability was assessed using Chi-square Automatic Interaction Detector (CHAID) statistical test.

RESULTS

A total of 210 participants (152 female & 58 male; 53.9 ± 6.5 years, range 41-71 years), representing 420 MFCL fits, equally distributed between emergent n = 65, established n = 70 and advanced n = 75 presbyopes, completed the studies. OVS on dispensing was the predictor of both OVS (p < 0.001) and ITP (p < 0.001) at 1-week. For OVS predictability, 70.8 % with OVS at dispensing > 91 points reported good OVS at 1-week and 73.4 % with OVS on dispensing ≤ 80 points reported poor OVS at 1-week. For ITP predictability, 74.6 % with OVS at dispensing > 94 points reported a positive ITP at 1-week and 65.9 % with OVS on dispensing ≤ 63 points reported negative ITP at 1-week.

CONCLUSION

Overall vision satisfaction at the time of dispensing MFCLs is a powerful indicator of both OVS and ITP after 1-week of wear. Initial patient subjective assessments provide a clinically useful indicator of the likeliness of success.

The influence of eyelid pressure and eye contour factors on rigid corneal contact lens fitting

PURPOSE

This study aimed to investigate the impact of eyelid pressure (ELP) and eye contour factors on rigid corneal contact lens fitting.

METHODS

This prospective cross-sectional study involved 20 participants (one eye per person). Rigid corneal contact lenses with three different base curves were selected for each participant. The base curves were calculated according to the average keratometry value. The original value and its variations (+0.1 mm and - 0.1 mm) were considered. Eye contour factors, lens decentration under natural eye position (LD I) and full eyelid exposure (LD II), and lens vertical movement were taken by a Canon camera mounted on a digital slit lamp biomicroscope. Upper and lower ELPs were measured by a novel blepharo-tensiometer.

RESULTS

The mean values of LD I, LD II, and lens vertical movement significantly increased as the base curve increased (P＜0.001, ＜0.001, and = 0.005). Upper ELP was positively correlated with lens vertical movement of the three base curves (P = 0.047, 0.001, and 0.004). Furthermore, upper ELP (odds ratio [OR]: 1.039; 95 % confidence [CI]: 1.009-1.069; P = 0.009) and flat keratometry values (OR: 0.873; 95 % CI: 0.786-0.969; P = 0.011) independently influenced lens vertical movement.

CONCLUSIONS

ELP and base curve independently influenced rigid corneal contact lens fitting. Thus, ELP should be considered during rigid corneal contact lens fitting in clinical practice.

Reliability and Agreement of Keratometry Measurements Obtained With Eye Surface Profilometry and Partial Coherence Interferometry

PURPOSE

The aim of this study was to assess the repeatability of keratometry parameters obtained using the Eye Surface Profiler (ESP) system and their agreement with the IOL Master 500 device.

METHODS

Seventy-one eyes of 71 healthy participants were evaluated. Three repeated measurements were performed using the ESP system. Simulated keratometry in the flat (SimKf) and steep (SimKs) meridians, astigmatism, and axis were obtained. The same parameters were measured using the IOL Master 500 device. The J0 and J45 vector components of the astigmatism were calculated. The intrasession repeatability was analyzed using within-subject SD (Sw) and intraclass correlation coefficient (ICC). Agreement was assessed using paired statistical tests and the Bland-Altman method.

RESULTS

The Sw was 0.07 mm, 0.04 mm, 0.51 D, 0.33 D, and 0.22 D, and the ICC was 0.96, 0.98, 0.74, 0.61, and 0.55 for SimKf, SimKs, astigmatism, J0, and J45, respectively. The mean difference and limits of agreement when comparing the ESP system with the IOL Master 500 device were 0.37 mm (0.08/0.66) for SimKf ( P < 0.001), 0.18 mm (0.00/0.35) for SimKs ( P < 0.001), -0.93 D (-2.42/0.56) for astigmatism ( P < 0.001), 0.51 D (-0.22/1.24) for J0 ( P < 0.001), and 0.06 D (-0.48/0.60) for J45 ( P = 0.09).

CONCLUSIONS

The ESP system provides consistent values for simulated keratometry, showing moderate consistency for astigmatism parameters. Contact lens practitioners should be aware that the ESP system and IOL Master 500 device provide different simulated keratometry from a clinically viewpoint.

2022 Glenn A. Fry Award lecture: Enhancing clinical assessment for improved ophthalmic management

ABSTRACT

Detailed clinical assessment is critical to allow sensitive evaluation of the eye and its management. As technology advances, these assessment techniques can be adapted and refined to improve the detection of pathological changes of ocular tissue and their impact on visual function. Enhancements in optical medical devices including spectacle, contact, and intraocular lenses have allowed for a better understanding of the mechanism and amelioration of presbyopia and myopia control. Advancements in imaging technology have enabled improved quantification of the tear film and ocular surface, informing diagnosis and treatment strategies. Miniaturized electronics, large processing power, and in-built sensors in smartphones and tablets capacitate more portable assessment tools for clinicians, facilitate self-monitoring and treatment compliance, and aid communication with patients. This article gives an overview of how technology has been used in many areas of eye care to improve assessments and treatment and provides a snapshot of some of my studies validating and using technology to inform better evidence-based patient management.

Current approaches to soft contact lens handling training - Global perspectives

PURPOSE

All neophyte contact lens wearers require training on how to handle contact lenses. Currently, almost no published information exists describing the most common approaches used by those involved in such training in soft contact lens wearers. This study aimed to gather information on the approaches taken by those conducting this training worldwide.

METHODS

An online survey was created in English and translated to Spanish and distributed internationally via social media, conference attendees, and professional contacts. The anonymous survey included information on workplace setting of respondents, information about the typical approaches used for application and removal of soft contact lenses, length of the appointment, and success rate with their approach. Survey responses were received between May 2021 and April 2022.

RESULTS

A total of 511 individuals completed the survey and responses were received from 31 countries with 48.7% from the UK. The most common approach taught for application was to have the patient hold the upper eyelashes (84.7%) and to hold the lower eyelid with the same hand as the lens (89.4%). Lenses were applied directly to the cornea by 57.7% of the respondents. The most common approach taught for lens removal was to drag the lens inferiorly from the cornea prior to removal (49.3%). Most respondents did not use videos to aid the teaching appointment (62.0%); however, they felt that their approach was successful in most cases (90). Application and removal training sessions lasted a median of 30 min and contact lenses were typically dispensed after the instructor witnessing successful application and removal three times.

CONCLUSION

Various methods are adopted globally for training of application and removal of soft contact lenses, with many advising a patient-specific approach is required for success. The results of this survey provide novel insights into soft contact lens handling training in clinical practice.

Clinical Investigation of Flat Pack Toric Contact Lenses and Wearer Attitudes to Environmental Impact

OBJECTIVES

To investigate the performance of a novel flat pack toric daily disposable contact lens compared with traditionally packaged toric lenses in a randomized, crossover study. Environmental attitudes to contact lens wear were also explored.

METHODS

Habitual contact lens wearers were recruited to wear a hioxifilcon A (Miru 1 day Flat Pack Toric, Menicon, Nagoya, Japan) test lens and a control lens: either nelfilcon A (Dailies AquaComfort Plus, Alcon, Geneva, Switzerland) or etafilcon A (1-Day Acuvue Moist, Johnson & Johnson, New Brunswick, NJ). Objective lens performance was assessed at fitting, and participants wore lenses in a randomized order for three consecutive days. Subjective measures of lens performance (comfort, vision, and handling) were then assessed by a questionnaire, with further questions on overall lens preference and environmental perceptions.

RESULTS

Objective measures of lens fit were similar for the test and control lenses, except for distance VA which was better with the control lenses ( P <0.05; difference of two logMAR letters). End of day comfort was greater with the test lens, but this did not reach significance. Both lenses demonstrated similar scores for overall satisfaction. 87.5% of participants indicated the environmental impact of contact lenses to be important/extremely important to them, with 100% of participants identifying the flat pack packaging as having a smaller environmental impact.

CONCLUSION

Overall, the lenses used in the study performed to similar levels. Environmental credentials are important to contact lens wearers, which may contribute to overall lens preference.

Development of corneal contact lens materials and current clinical application of contact lenses: A review

Unlike conventional glasses, corneal contact lenses (CLs) can directly contact the surface of the tear film through the application of biopolymer materials, to achieve therapeutic and cosmetic purposes. Since the advent of polymethylmethacrylate, a material that has gained widespread use and attention, statistically, there are now more than 150 × 106 people around the world who wear corneal contact lenses. However, the associated complications caused by the interaction of contact lenses with the ocular surface, tear film, endogenous and environmental microorganisms, and components of the solution affect nearly one-third of the wearer population. The application of corneal contact lenses in correcting vision and myopia control has been widely recognized. With the development of related materials, corneal contact lenses are applied to the treatment of ocular surface diseases, including corneal bandage lenses, drug-loaded corneal contact lenses, biosensors, and other new products, while minimizing the side effects associated with CL wear. This paper summarized the development history and material properties of CLs, focused on the current main clinical applications and mechanisms, as well as clarified the possible complications in wearing therapeutic contact lenses and the direction for improvement in the future.

TFOS Lifestyle: Impact of contact lenses on the ocular surface

Several lifestyle choices made by contact lens wearers can have adverse consequences on ocular health. These include being non-adherent to contact lens care, sleeping in lenses, ill-advised purchasing options, not seeing an eyecare professional for regular aftercare visits, wearing lenses when feeling unwell, wearing lenses too soon after various forms of ophthalmic surgery, and wearing lenses when engaged in risky behaviors (e.g., when using tobacco, alcohol or recreational drugs). Those with a pre-existing compromised ocular surface may find that contact lens wear exacerbates ocular disease morbidity. Conversely, contact lenses may have various therapeutic benefits. The coronavirus disease-2019 (COVID-19) pandemic impinged upon the lifestyle of contact lens wearers, introducing challenges such as mask-associated dry eye, contact lens discomfort with increased use of digital devices, inadvertent exposure to hand sanitizers, and reduced use of lenses. Wearing contact lenses in challenging environments, such as in the presence of dust and noxious chemicals, or where there is the possibility of ocular trauma (e.g., sport or working with tools) can be problematic, although in some instances lenses can be protective. Contact lenses can be worn for sport, theatre, at high altitude, driving at night, in the military and in space, and special considerations are required when prescribing in such situations to ensure successful outcomes. A systematic review and meta-analysis, incorporated within the review, identified that the influence of lifestyle factors on soft contact lens dropout remains poorly understood, and is an area in need of further research. Overall, this report investigated lifestyle-related choices made by clinicians and contact lens wearers and discovered that when appropriate lifestyle choices are made, contact lens wear can enhance the quality of life of wearers.

Novel High-Resolution Imaging Using ANTERION Optical Coherence Tomography to Assess Fluid Reservoir Change in Scleral Lens Periphery

OBJECTIVES

To assess scleral lens fluid reservoir (FR) change simultaneously in four quadrants with single acquisition using novel ANTERION anterior segment swept-source optical coherence tomography (SS-OCT).

METHODS

A prospective, observational, clinical study of 18 subjects (30 eyes) was performed on adults fitted with a scleral lens for ocular surface disease (n=8), irregular cornea/scar (n=7), and corneal ectasia (n=15). ANTERION anterior segment SS-OCT imaging was obtained at the initial visit and at the follow-up to determine pre and post scleral lens settling, measured in microns, centrally and peripherally. Peripheral measurements were grouped into four quadrants. Repeated-measures ANOVA was performed comparing vault post minus pre differences by quadrant, and TTests comparing difference in FR by lens design were performed with a significant threshold at P <0.05.

RESULTS

The mean central scleral lens settling was significant at -48.3±41.7 μm. The change in FR by quadrant was superior (S): -47.8±67.3 μm, inferior (I): -68.0±102.2 μm, nasal (N) -46.3±63.4 μm, and temporal (T): -56.7±49.3 μm. There were no significant differences in lens settling between the quadrants. Within the three categories, the irregular cornea group experienced significantly greater lens settling. There was no significant difference in central FR when comparing lens design or lens diameter.

CONCLUSIONS

The ANTERION SS-OCT allows for high-resolution central and peripheral assessment of FR in scleral lens wear. With increased technology available for scleral lens customization, this imaging modality can assist in more detailed assessment in quadrant-specific scleral lens designs.

Role of therapeutic contact lenses in management of corneal disease

PURPOSE OF REVIEW

The current review highlights areas of innovation and research in the use of contact lenses in the treatment of corneal ectasia and ocular surface disease.

RECENT FINDINGS

A series of academic reports were published by a committee of experts reviewing evidence-based practice patterns of contact lens use. There continues to be active research in the use of contact lenses in the management of keratoconus, including mini-scleral lenses, custom impression-based scleral lenses and wavefront-guided scleral lenses. Recent reports on contact lenses for ocular surface disease were primarily reviews, retrospective case reports or case series, with publications on contact lens use in corneal epithelial defects, graft-vs.-host disease, limbal stem cell deficiency and neurotrophic keratitis. There are recent publications on advances in drug-eluting contact lenses.

SUMMARY

Corneal specialists should be aware of current advances in the field of contact lens expanding their use in corneal ectasia and ocular surface disease.

Anterior ocular surface sagittal height prediction

PURPOSE

To investigate the validity of Placido-based corneal topography parameters to predict corneoscleral sagittal heights measured by Fourier-based profilometry at various diameters.

METHODS

Minimal (Min_sag ), maximal (Max_sag ) sagittal height, toricity (Max_sag  - Min_sag ) and axis of the flattest meridian (Min_sag ) of 36 subjects (mean age 25.4 SD ± 3.2 years; 21 female) were measured using the Eye Surface Profiler and analysed for diameters (chord length) of 8 to 16 mm (in 2-mm intervals). Furthermore, corneal central radii, corneal astigmatism, eccentricity and diameter were measured using the Keratograph 5 M.

RESULTS

Using multiple linear regression analysis, the best equation for predicting the sagittal heights for 8 mm (r²  = 0.95), and 10 mm (r²  = 0.93) diameters included corneal central radii and eccentricity. The best equation for predicting sagittal heights for 12 mm (r²  = 0.86), 14 mm (r²  = 0.78) and 16 mm (r²  = 0.65) diameters included corneal central radii, eccentricity and corneal diameter. Corneal astigmatism was significantly correlated with sagittal height toricity for 8 and 10 mm diameters (r²  = 0.50 and 0.29; p < 0.01), while no correlation was observed for 12, 14 and 16 mm diameters (p = 0.18 to p = 0.76). The axis of the flattest corneal meridian measured by Placido-based topography was significantly correlated with the axis of the flattest meridian measured by Fourier-based profilometry for 8, 10 and 12 mm diameters (r²  = 0.17 to 0.44; p < 0.05), while there was no correlation for 14 and 16 mm diameters (p = 0.48 and p = 0.75). For a typical soft contact lens diameter of 14 mm, 78% of the variance could be determined with a corneal topographer and 68% with keratometry and corneal diameter measurement.

CONCLUSIONS

The combination of corneal central radii, eccentricity and corneal diameter measured by Placido-based topography is a valid predictor of the corneoscleral sagittal height in healthy eyes. Scleral toricity and axis of the flattest meridian seem to be independent from Placido-based corneal parameters and requires additional measuring tools.

Quality-of-life outcomes of long-term contact lens wear: A systematic review

PURPOSE

The aim of this review was to evaluate the evidence on quality-of-life outcomes of long-term contact lens wear.

METHODS

A search for original articles that used validated measures to evaluate patient-reported outcomes (PROs) in long-term (≥2 years) contact lens wearers was conducted in Medline Ovid, PubMed, Scopus, Web of Science, Cochrane, CINAHL, and PsycInfo databases. The information including PRO measure (name, type, content) and key quality-of-life outcomes findings were extracted.

RESULTS

Seven articles that used 4 PRO measures to evaluate quality of life outcomes of long-term contact lens wear met the inclusion criteria. The median (range) number of contact lens wearers in these studies was 116 (31-247). The studies were conducted in 4 countries: USA, Spain, China, and Russia. All studies were conducted in myopic populations. None of the studies provided information on psychometric properties, validity and reliability of the PRO measures used. Five studies were conducted in children of which 3 studies evaluated PROs of myopia control contact lens wear. The studies reported that contact lens wear, including myopia control lens wear, was an effective method of refractive correction in children and adults in the long term in PRO-perspective, and resulted in a better quality of life status than with glasses. However, long-term dry eye and discomfort related symptoms were reported.

CONCLUSION

Overall, contact lens use improved quality of life status in children and adults. More research is required to better understand the long-term quality-of-life outcomes of contact lens wear.

All soft contact lenses are not created equal

Soft contact lenses that have been prescribed by eye care practitioners are sometimes substituted for alternative lenses by unqualified, unregulated and sometimes even fully regulated lens suppliers, in the mistaken belief that there is essentially no difference between different soft lens types. This review considers the implications of inappropriately substituting soft contact lens types in terms of (a) lens properties: surface treatment, internal wetting agents, material, total diameter, back optic zone radius, thickness, edge profile, back surface design, optical design, power, colour (tint) and ultraviolet protection; and (b) lens usage: wearing modality (daily versus overnight wear) and replacement frequency. Potential aspects of patient dissatisfaction and adverse events when prescribed soft lenses are substituted for lenses with different properties or intended usage are considered. Substitution of 15 of the 16 lens properties considered (i.e. except for back surface design) was found to be related to at least one - and as many as six - potential sources of patient dissatisfaction and adverse ocular events. Contact lens are medical devices which are prescribed and fitted; they should never be substituted for another lens type in the absence of a new prescription further to a full finalised fitting, for the simple reason that all soft contact lenses are not created equal. A substituted lens may have properties that results in undesirable consequences in respect of vision, ocular health, comfort and cosmetic appearance, and may be incompatible with the lifestyle of the patient.

Opportunities and threats to contact lens practice: A global survey perspective

AIM

To understand the views of contact lens (CL) practitioners across the globe regarding what they perceive as opportunities and threats in CL practice.

METHODS

A self-administered anonymised questionnaire, constructed in English and translated in six more languages, was distributed through reputed international professional bodies and academic institutions worldwide. The questionnaire included items on demographic characteristics, type of practice, and questions designed to explore practitioners' perspective on the future of their CL practice over the next five years.

RESULTS

A total of 2408 valid responses were analysed. Multifocal CLs for presbyopia, CLs for myopia control, use of daily disposable (DD) CLs for occasional wear, and biocompatible materials to improve comfort were identified as promising areas of opportunities by practitioners (all 8/10). Respondents from North America, and Europe valued DDCLs for occasional wear moderately more favourable (Median: 9/10 for all) as compared to colleagues in Asia (Median: 8/10, p < 0.001), South America (Median: 8/10, p < 0.01), and Africa (Median: 8/10p < 0.01). Multifocal CLs for presbyopia was perceived as a better opportunity by practitioners in North America and Europe (Median: 9/10 for both), as well as in Australasia (Median: 8/10), in comparison to Asia, Africa, and Middle East (for all Median: 6/10, p < 0.001). Practitioners expressed concerns about the availability of CLs and CL prescriptions online without direct professional involvement (both 9/10).

CONCLUSIONS

Overall, the most appealing opportunities for CL practice growth were identified in occasional use of DD CLs, biocompatible materials to reduce CL discomfort, multifocal CLs for presbyopia correction and management of myopia control with CLs. Lack of regulation in CL sales, especially online, seemed to be a constant threat. The insights from this study can be used to design targeted strategies to enhance CL practice across the globe and in specific geographical areas.