Spectacle Prescription Research Articles

Myopia: An ounce of prevention is worth a pound of cure.

Myopia severity has a profound impact on visual impairment in later life. A patient's final level of myopia may be lowered by myopia control, but also by delaying onset. Here, we evaluate the influence of the age of onset on the final recorded level of myopia. Data were extracted from: (1) Three prospective cohort studies of myopia progression in East Asia and the United States where the final recorded level of myopia is presented as a function of the established age of onset. (2) Four retrospective studies of myopia progression in Finland, India, the Netherlands and China and two cross-sectional studies in Argentina and the UK where the age of onset was based on self-report of age at first spectacle prescription. (3) A cohort study of Finnish subjects originally recruited for a clinical trial and followed into adulthood. Subjects were divided into five groups according to age at recruitment that was used as a surrogate for the age of onset. Final recorded level of myopia was plotted as a function of age of onset for all studies. Among the three East Asian studies, the slopes are between 0.68 and 0.97 D/year, meaning that each later year of onset is associated with between 0.68 and 0.97 less myopia at the final recorded refraction. For six of the seven non-East Asian studies, the slopes are substantially flatter, with slopes between 0.23 and 0.50 D/year. By contrast, the slope for the Finnish study was 0.87 D/year. Increasing age of final recorded refraction tended to be associated with higher levels of myopia. Among East Asians, delaying the onset of myopia by 1 year has the potential to lower the final myopia level by 0.75 D or more-equivalent to 2-3 years of myopia control with existing modalities. The benefit is lower, but meaningful, among non-East Asians.

The Use of Chromagen Lenses in Different Ocular and Non-ocular Conditions: A Prospective Cohort Study.

BackgroundIn this study, we aimed to evaluate the efficacy of chromagen lenses and compare the pre- and post-intervention outcomes among individuals with non-ocular conditions such as dyslexia and Irlen syndrome and ocular conditions such as color vision deficiency (CVD) and cone-rod dystrophy (CRD).MethodologyThis prospective cohort study was conducted from 2016 to 2021 among cases (seven years or older) who were diagnosed with dyslexia, Irlen syndrome, CVD, or CRD. Participants were given a short questionnaire to read, followed by asking direct questions regarding medical health history, ocular history, eyeglasses prescription, and a full orthoptics evaluation. The main outcomes were the improvement in reading speed, reading accuracy, and visual stress.ResultsA total of 156 patients were included in this study; 110 patients with dyslexia, 19 with Irlen syndrome, 16 with CVD, and 11 with CRD. The findings showed that the reading speed and accuracy were improved in 96.34% of patients with dyslexia and 78.9% of patients with Irlen syndrome. The use of a chromagen lens was significantly associated with visual stress improvement in 89.8% of patients (p = 0.02). Photosensitivity was significantly improved after wearing the chromagen lenses in patients with CVD (87.5%) and CRD (63.6%).ConclusionsThe study findings showed a positive impact of chromagen lenses on reducing visual stress, including reading speed and accuracy, in patients with dyslexia and Irlen syndrome. Photosensitivity improved in patients with Irlen syndrome and CRD. Color vision was enhanced in patients with CVD. However, further studies are required to investigate the predictors of improvement and assess the long-term efficacy of chromagen lenses on daily activities and learning skills.

Changes in utilisation of optometry services with a non-targeted publicly-funded health care voucher system

ABSTRACT Clinical relevance Understanding the impact of a health care voucher scheme and service access barriers could facilitate optometry service promotion to the older population. Background A voucher is one strategy to improve the utilisation of the different health care services available in the private sector. This study aims to explore how a health care voucher system for older people impacts utilisation of optometry services from the perspective of service users and service providers. Methods People aged 65 years or above were recruited to fill in a structured questionnaire studying the usage characteristics and access barriers of optometry services and the health care voucher. Views from the optometrists about the voucher scheme were collected by questionnaire. Results A total of 1156 valid questionnaires from eligible voucher users was collected. Results showed that 53.7% (621/1156) of participants had used optometry services within the past 2 years. Lack of familiarity with services provided, professional fees, and prices of spectacles were the main barriers to using optometry services. Of those participants who had used the voucher for optometry services previously, 80.4% (284/353) had an eye examination in the past 2 years. Among 389 optometrists who participated in the study, over 80% agreed that the voucher scheme improved awareness of major eye conditions and access to prescription spectacles when necessary. Conclusion The health care voucher for older people improved access to optometry services. Access could be further improved by increasing price transparency of professional services and prescription spectacles. Responses from optometry service providers supported the view that the voucher scheme improved access to, and utilisation of, preventive care services.

Affluence and Contact Lens Prescribing.

To assess the impact of national affluence on the extent of prescribing of various types of soft contact lenses. Using information derived from a large bank of contact lens prescribing data, the relationship between the percentage prescribing of daily disposable, toric, silicone hydrogel, and multifocal contact lenses versus the gross domestic product at purchasing parity per capita (GDP [PPP]) was determined for all countries in which contact lens prescribers returned survey forms relating to greater than 100 contact lens fits between 2017 and 2021, inclusive. Data from 39 countries were analyzed, comprising 94,181 contact lens fits. The relationship between percentage contact lens prescribing versus GDP (PPP) was highly statistically significant for daily disposable lenses (r 2 =0.35, P <0.0001), marginally significant for toric lenses (r 2 =0.08, P =0.06), and not significant for silicone hydrogel lenses (r 2 =0.01, P =0.42) or multifocal lenses (r 2 =0.02, P =0.35). The rate of prescribing daily disposable contact lenses, and to a lesser extent toric lenses, is related to national affluence. The contact lens industry, practitioners, and governments/regulatory bodies should remain cognizant of this association and, where possible, reduce cost barriers to the purchase of such contact lens products so that they can be prescribed based on important clinical, refraction, and lifestyle considerations.

Contact Lens Prescribing Patterns in a University Clinic in Trinidad and Tobago.

The study assessed the contact lens prescribing patterns and associated factors in a university optometry clinic in Trinidad and Tobago. The data relating to habitual or new contact lens (CL) prescribing patterns among wearers over a two-year period were reviewed. Pearson’s chi-squared test and logistic regression models were used to analyze the findings. The Hosmer–Lemeshow goodness-of-fit test was used to examine the model calibration. A total of 243 CL fits were analyzed, and the Homeshow–Lemeshow goodness-of-fit test indicated a good fit (χ2 (7) = 7.296, p = 0.399). The mean age of lens wearers was 29.6 ± 12.4 (mean ± SD); the majority, 155 (63.8 %) of whom, were 21 to 40 years old. Most lenses were fitted on females (64.2% of fits overall) and about half of the wearers (n = 122, 50.2%) were prescribed lenses for cosmetic purposes. Conventional soft CL were the most prescribed modality of wear, accounting for 129 (53.1%) of the fits. Age from 21 to 40 years was the predictor of lens type prescribed, and those in that age range were four times more likely to be prescribed soft lenses compared to other ages. The patterns of CL prescribing in a university optometry clinic in Trinidad and Tobago are similar to the global market trends with slight variations.

Calibration of transverse ray and pupil aberrations for light field cameras.

The accuracy of reconstructing depth maps or performing digital refocusing in light field cameras depends largely on how well the spatial and angular samples of light rays can be obtained. Ray sample errors induced by optical aberrations in a light field camera may be digitally corrected using the ray tracing data when its nominal lens design is available. However, the most commonly nominal lens prescription is not accessible to end users. Additionally, even if available, due to tolerances in optomechanical design, the ray tracing data can be inaccurate. We propose a calibration method based on measurements of fiducial markers on a checkerboard for modeling the imaging properties of light field cameras. The calibration accounts for vignetting, transverse ray errors, as well as pupil aberration, and can be applied to light field camera modeling of arbitrary pupil sampling systems. We further demonstrate the utility of the method for calibrating a tri-aperture camera that captures simultaneous stereo views via artificially induced transverse ray errors.

Limbal-Rigid Contact Lens Wear for the Treatment of Ocular Surface Disorders: A Review.

:Recently, the prescription of large-diameter rigid gas-permeable contact lenses (CLs), also known as “scleral lenses,” “corneoscleral lenses,” and “limbal-rigid CLs,” is on the rise for the treatment of both moderate and severe ocular surface disorders (OSDs). Compared with scleral lenses, the diameter of limbal-rigid CLs is generally smaller, that is, a diameter ranging from 13.0 to 14.0 mm, and they are designed so that the peripheral edge bears on the limbus. The Suncon Kyoto-CS (Sun Contact Lens Co., Ltd.) is a novel limbal-rigid CL design with multistep curves on the peripheral edge for easy tear exchange during blinking that removes debris and prevents lens clouding or fogging, thus allowing patients to enjoy a longer daily duration of CL wear. In severe OSD cases, limbal-rigid CL wear after surgery is a noninvasive therapeutic approach that can neutralize corneal irregularities, decrease dry eye symptoms, prevent the progression or recurrence of symblepharon, and improve the patient's visual acuity and overall quality of life. Thus, surgeries such as amniotic membrane transplantation and cultivated oral mucosal epithelial transplantation, as well as limbal-rigid CL wear, which is noninvasive, are valuable and effective treatment strategies that can now be applied for the management of patients afflicted with severe OSDs.

Clinical performance of a custom-designed soft contact lens in patients with keratoconus and intolerance to rigid contact lenses.

This study evaluated the efficacy and safety of YOUSOFT® soft contact lens (CL) (TOMEY-CL) in patients with keratoconus and intolerance to rigid CLs. Retrospective observational study. Thirty-six eyes of 20 patients (14 men and 6 women) with keratoconus and rigid CL intolerance were included in the study. Four patients were unilateral. The mean age was 33.1 ± 11.7 (± standard deviation) years, the mean spherical refractive error was -4.99 ± 3.97 D, and the mean cylindrical refractive error was -3.39 ± 2.13 D. The following examinations were performed at baseline and were repeated at every visit; refractometry, visual acuity, corneal topography and pachymetry with an anterior OCT system. Corneal endothelial cell density was evaluated at baseline and every 6 months. Slit-lamp examination was also performed to confirm the CL condition and ocular health at every visit. Seventeen patients (85%) were able to continue using the Yousoft. Among 3 patients (15%) who dropped out, 2 were dissatisfied with their visual outcomes and one had trouble with lens handling. Uncorrected visual acuity was 1.08 ± 0.43 (range: 0.22 to 2.00) logMAR at baseline, and best CL-corrected visual acuity was 0.01 ± 0.15 (range: -0.18 to 0.40) logMAR, showing a significant improvement after wearing Yousoft (P < 0.0001). The endothelial cell density did not change significantly, with 2373 ± 482 at baseline and 2402 ± 464 cells/mm2 at the latest visit after lens prescription (P = 0.351). There were no severe complications such as corneal infiltrates or infectious keratitis throughout the study period. This study showed the efficacy and acceptable safety of Yousoft for patients with keratoconus and intolerance to rigid CLs.

Commentary: Wavefront aberrometry-based objective refraction - Accuracy versus convenience?

Objective measurement of refraction manually by static retinoscopy followed by subjective refraction has been a historically revered method of prescribing glasses to patients. Even though time consuming and variable, this conventional approach is still considered optimal method of refraction among optometrists and ophthalmologists in their clinical practice. However, recently, wavefront aberrometer-based objective refraction technology is gaining popularity over the conventional refraction methods due to the ease of performing the evaluation and reproducibility of the clinical data. This novel method is touted to give repeatable results in few seconds of evaluation time. Studies comparing objective autorefractors and conventional objective and subjective refraction indicate that these autorefractors are satisfactory for a preliminary refraction, but are not satisfactory as substitutes for subjective refraction.[1] Many studies have shown strong agreement between autorefraction and subjective refraction and less stronger agreement between wavefront aberrometer-based refraction and subjective refraction.[2] In the following study titled “The Pentacam® AXL Wave provides a reliable wavefront-based objective refraction when compared to manifest subjective refraction: A prospective study,” the authors have attempted to prove the reliability of Pentacam® AXL Wave’s wavefront-based objective refraction vis-à-vis manifest refraction using a phoropter. This latest instrument launched by Oculus (Optikgeräte GmbH, Wetzlar, Germany) is based on Hartman Shack aberrometer principle combining Scheimpflug corneal tomography and partial coherence interferometry.[3] This type of aberrometers can identify various higher- and lower-order aberrations and convert these into vector representations in sphere, cylinder, and astigmatic errors based on Zernike polynomials. The authors have used Thibos method of conversion of refraction values into power vectors for interpretation and analysis. Thibos, in his paper, in the year 2004, had himself concluded that there exist sources of error while converting wavefront aberration maps to refractive prescriptions, and thus suggested the need for future experiments that could resolve these uncertainties and achieve more accurate and precise method of objective wavefront refraction.[4] The authors have compiled the results well and gone in detail with the statistics to alleviate any bias; however, they have compared the wavefront aberrometry with subjective refraction using automated refractometer and phoropter-based evaluation. They have not performed retinoscopy under cycloplegia, which is considered gold standard in clinics all around the globe. Not to forget the increasingly reported evidence of ectatic disorders like keratoconus in patients turning for refraction, in whom the subjective and aberrometry-derived spherical equivalent refraction data are noted to be significantly different. The larger the magnitude of the higher-order aberrations in keratoconic eyes, the poorer the subjective refraction LogMAR acuity and the larger the difference between the subjective and aberrometer-derived power vector terms.[5] Spectacle prescription in such patients cannot be relied upon completely based on the aberrometer-based objective methods of refractive error assessment. Hence, from a personal perspective, we can conclude that it would have been more appropriate to compare this new method of aberrometer refraction with aberrometers which show good correlation with conventional refraction methods, as this would give us a better idea as to where this product stands in the current market. The ability to automatically refract a patient and provide a spectacle prescription, equivalent to the time-consuming current gold standard retinoscopy followed by subjective refraction, is an elusive goal, but definitely a step toward significant clinical advancement and, if proven superior, has the ability to introduce a revolution in the field of optometry and ophthalmology.

Non-Organic Visual Loss in Children and Teenagers

Functional visual disorders in children and adolescents are an important but challenging differential diagnosis. What is characteristic is the discrepancy between the symptomatology and the objective findings. The aim of our work was to analyse the data of those patients who were cared for at our clinic with the diagnosis "functional visual disorders". A retrospective data analysis was performed: age < 18 years, with diagnosis "functional visual disorder" 2011 to 2020. Historical and clinical data were extracted from the patient's file. In addition, parents or patients were contacted using a questionnaire about current symptoms. The study was approved by the cantonal ethics committee of Zürich (KEK Nr. 2020-01268). A total of 92 patients were identified, and analysis could be performed in 53% (49/92; 32 female, 17 male) with available consent. The age ranged from 3 to 18 years (median 10.5 years) with a follow-up of 1 to 58 months (median 7months). The most common symptoms were bilateral visual loss (55%) and/or blurred vision (18%) with headache (35%), motility pain (14%), photophobia (4%), dizziness (4%), and malaise (2%). A reduction in distant (22/49 bilateral, 9/49 unilateral) and near (24/49 bilateral, 3/49 unilateral) visual acuity was documented. Subjective visual acuity reduction was no longer detectable in 20% of patients at testing. Psychological distress was documented in 13/49 patients. Moisturising eye drops (18/49), eyeglass prescription (15/49), or no therapy (20/49) was recommended. Subjective and/or objective improvement was documented at follow-up in 49% (24/49). The questionnaire was answered in 86%: no complete remission of visual symptoms (10/42), remission within 1 week (14/41), 1 month (3/41), 2 - 6 months (8/41), 1 year (6/41). There was no correlation between duration of visual symptoms and age at onset or gender. The consultation at our clinic was reported as "supportive and helpful" in 31/42 patients. Despite a low incidence during the history, the psychosocial and psychological component should not be neglected.

Contact lens prescribing trends in the UK hospital eye service

PurposeThe aim of this study was to evaluate the types of contact lenses fitted by hospital optometrists within the Midlands region of the United Kingdom (UK). MethodA questionnaire was sent to all the lead optometrists of the Midlands Hospital Optometry Group (MHOG). This group includes optometry hospital eye departments within the Midlands region of the UK. The questionnaire requested information of their last ten contact lens fitting appointments. Details of the patient’s age, gender, lens type, wearing times, and presenting condition were retrospectively taken from the patients’ records using the appointment diary to identify the last ten patients fitted with contact lenses. ResultsDetails from a total of 109 contact lens fits were collected. This included 45 females and 64 males with a mean age of 39.4 ± 17.4 years. The mean wearing time was 6.3 ± 1.0 days per week and 10.7 ± 5.1 h per day. Sixty-one percent of the contact lenses fitted were for patients with keratoconus and over half of all the contact lenses fitted were corneal rigid gas permeable lenses. ConclusionThis study highlighted that the main reason for fitting contact lenses in hospital contact lens practice is primary corneal ectasia, and mainly keratoconus. Whilst most patients with keratoconus were fitted with corneal rigid gas permeable contact lenses, around 1 in 6 were fitted with soft contact lenses. This study addresses a gap in the literature about contact lenses fitted in UK hospitals and how they differ from community contact lens practice.

Strategies and attitudes on the management of myopia in clinical practice in Spain

ObjectiveIn 2019, an international survey was conducted to evaluate strategies and attitudes in the management of myopia in clinical practice worldwide. This study reports on the results found in Spain and how these results compare with those from other regions of the world. MethodsA self-administrated, internet-based questionnaire was distributed to eye care professionals around the world through professional associations. The questions examined were based on the available strategies and their use. ResultsA total of 173 Spanish optometrists, of the 1,336 practitioners from the five different continents who participated in the study, responded to the online survey. Spain, Asia and South America were found among the regions with the highest concern regarding the increased incidence of myopia (p ≤ 0.001). However, in these regions, the prescription of single-vision spectacles and single-vision contact lenses continues to be the main methods of visual correction prescribed to young myopic patients (p ≤ 0.001). Spanish practitioners, like those from other regions, considered orthokeratology to be the most effective treatment to control myopia progression (p ≤ 0.001). The major reasons why Spanish practitioners were not prescribing myopia control strategies were increased cost, inadequate information and unpredictable outcomes (p < 0.05). ConclusionsThe uptake of myopia control methods by Spanish practitioners is relatively low, despite the increase in the prevalence of paediatric myopia as well as increased concern and perceived clinical activity in the area in recent years.

Binocular Dynamic Visual Acuity in Eyeglass-Corrected Myopic Patients

Current clinical visual assessment mainly focuses on static vision. However, static vision may not sufficiently reflect real-life visual function as moving optotypes are frequently observed daily. Dynamic visual acuity (DVA) might reflect real-life situations better, especially when objects are moving at high speeds. Myopia impacts static uncorrected distance visual acuity, conveniently corrected with eyeglasses. However, due to peripheral defocus and prism effects, eyeglass correction might affect DVA. The present research demonstrates a standard method to examine eyeglass-corrected DVA in myopia patients, and aimed to explore the influence of eyeglass correction on DVA. Initially, standard subjective refraction was performed to provide the eyeglass prescription to correct the refractive error. Then, binocular distance vision-corrected DVA was examined using the object-moving DVA protocol. Software was designed to display the moving optotypes according to the preset velocity and size on a screen. The optotype was the standard logarithmic visual chart letter E and moves from the middle of the left to the right side horizontally during the test. Moving optotypes with randomized opening direction for each size are displayed. The subjects were required to identify the opening direction of the optotype, and the DVA is defined as the minimum optotype that subjects could recognize, calculated according to the algorithm of logarithmic visual acuity. Then, the method was applied in 181 young myopic subjects with eyeglass-corrected-to-normal static visual acuity. Dominant eye, cycloplegic subjective refraction (sphere and cylinder), accommodation function (negative and positive relative accommodation, binocular cross-cylinder), and binocular DVA at 40 and 80 degrees per second (dps) were examined. The results showed that with increasing age, DVA first increased and then decreased. When myopia was fully corrected with eyeglasses, a worse binocular DVA was associated with more significant myopic refractive error. There was no correlation between the dominant eye, accommodation function, and binocular DVA.

Binocular Dynamic Visual Acuity in Eyeglass-corrected Myopic Patients.

Current clinical visual assessment mainly focuses on static vision. However, static vision may not sufficiently reflect real-life visual function as moving optotypes are frequently observed daily. Dynamic visual acuity (DVA) might reflect real-life situations better, especially when objects are moving at high speeds. Myopia impacts static uncorrected distance visual acuity, conveniently corrected with eyeglasses. However, due to peripheral defocus and prism effects, eyeglass correction might affect DVA. The present research demonstrates a standard method to examine eyeglass-corrected DVA in myopia patients, and aimed to explore the influence of eyeglass correction on DVA. Initially, standard subjective refraction was performed to provide the eyeglass prescription to correct the refractive error. Then, binocular distance vision-corrected DVA was examined using the object-moving DVA protocol. Software was designed to display the moving optotypes according to the preset velocity and size on a screen. The optotype was the standard logarithmic visual chart letter E and moves from the middle of the left to the right side horizontally during the test. Moving optotypes with randomized opening direction for each size are displayed. The subjects were required to identify the opening direction of the optotype, and the DVA is defined as the minimum optotype that subjects could recognize, calculated according to the algorithm of logarithmic visual acuity. Then, the method was applied in 181 young myopic subjects with eyeglass-corrected-to-normal static visual acuity. Dominant eye, cycloplegic subjective refraction (sphere and cylinder), accommodation function (negative and positive relative accommodation, binocular cross-cylinder), and binocular DVA at 40 and 80 degrees per second (dps) were examined. The results showed that with increasing age, DVA first increased and then decreased. When myopia was fully corrected with eyeglasses, a worse binocular DVA was associated with more significant myopic refractive error. There was no correlation between the dominant eye, accommodation function, and binocular DVA.

Rapid progression of myopia at onset during home confinement

To determine whether the myopic shift at myopia onset was faster than usual during home confinement associated with the COVID-19 pandemic. Data on refractive error in consecutive children who presented for their first myopic spectacle prescription from September 2020 to May 2021 (new-onset myopia during the pandemic) were collected. Inclusion criteria were age 5-18 years and cycloplegic spherical equivalent in both eyes in the emmetropic range in the pre-pandemic years as recorded 1 year and 2 years before the actual visit. Annualized mean myopic shifts over the two previous periods were calculated. A total of 39 subjects (59% girls) were enrolled. Mean age at the visit after confinement was 10.79 ± 2.83 years. The mean refractive error for the right eyes in 2018 was +0.29 ± 0.56 D. The year after (2019), these children had a mean spherical equivalent of -0.12 ± 0.70 D. At the enrollment visit after myopia onset in the pandemic period, they had myopia of -1.33 ± 0.73 D. The mean annualized myopic shift for the right eyes was -0.37 ± 0.43 D before the pandemic and -1.12 ± 0.70 D during the pandemic period that included home confinement (P < 0·001 [Wilcoxon text]). Previous pre-pandemic prospective studies have reported myopic shift at onset of approximately -0.80 D. The period of strict pandemic home confinement saw higher rates of myopic shift.

Better safe than sorry? Results from an ex-vivo study demonstrate that the thulium fiber laser may cause eye injury without standard protection.

We conducted a study using an ex-vivo porcine model to evaluate whether a thulium fiber laser (TFL) induces ocular injury in the context of inadvertent exposure to the laser beam. A 365 μm TFL was positioned at a set distance (0 cm, 5 cm, 8 cm, and 10 cm) from a freshly harvested (<12 hours) porcine eyeball and the laser was activated for one second at select laser settings for lithotripsy (0.2 J at 50 Hz, 0.5 J at 20 Hz, and 1 J at 10 Hz) and soft tissue ablation (2 J at 10 Hz, 1 J at 50 Hz). The experiment was repeated with laser safety goggles and prescription eyeglasses. Thermal injury was assessed by histopathological analysis. Without eye protection, corneal injury was observed even at 10 cm away for one lithotripsy setting (1 J at 10 Hz) and both tissue ablation settings. All thermal injuries observed were superficial only, except for at 0 cm distance, where deep-layer injury was observed. Laser safety goggles offered complete protection regardless of setting or distance. Partial protection was demonstrated with prescription glasses: histopathological damage was observed for both soft tissue ablation settings and only at 0 cm for two lithotripsy settings (0.5 J at 20 Hz, 1 J at 10 Hz). The TFL can induce ocular injury at close distances and at higher power settings. The use of laser safety goggles confers complete protection while prescription eyeglasses confer partial protection. Further study is warranted.

Quality of refractive error care (Q.REC) in Cambodia, Malaysia and Pakistan: protocol for a cross-sectional unannounced standardised patient study

IntroductionThere are 161 million people living with vision impairment, due to uncorrected refractive errors. A further 510 million people are living with near-vision impairment. There is a need for clearly...

Global contact lens prescribing 2000-2020

ABSTRACT Clinical relevance Contact lens prescribing data serve as a benchmark for eye care clinicians in assessing their own prescribing patterns and provide useful contextual information for researchers and the contact lens industry. Purpose To document global trends in contact lens prescribing during the first two decades of this century. Methods A longitudinal survey of contact lens prescribing was conducted by asking contact lens practitioners to provide 11 items of information from 10 consecutive contact lens fits between January and March each year from 1996 to 2020, inclusive. Results Data relating to 406,859 contact lens fits were collected from 71 countries between 1996 and 2020, generating 4.5 million data points. Demographic analysis for 61 nations returning ≥100 fits demonstrated that a majority of lenses (65–70%) were fitted to females. The average age of lens wearers was 30.8 ± 13.9 years for males and 32.5 ± 14.3 years for females. Trend analysis of 20 countries returning prescribing data for ≥13 years between 2000 and 2020 revealed the following: increase in the age of lens wearers; dramatic rise in the extent of fitting silicone hydrogel and daily disposable lenses; increased fitting of soft toric and multifocal lenses; increasing proportion of rigid lens fits in specialist (non-spherical) designs; incomplete provision of near contact lens corrections for contact lens wearing presbyopes; ongoing low levels of extended wear fits; and almost exclusive use of multi-purpose care systems. Daily disposable lenses were used for both full-time and part-time wear, whereas rigid and soft reusable lenses were primarily worn full time. Conclusions The evolution of international contact lens fitting over the first two decades of this century is documented. The data presented here may assist all stakeholders in advancing contact lens clinical practice, informing contact lens research, and guiding contact lens manufacturers.

Causes of functional low vision in a Brazilian rehabilitation service

There is limited information on functional low vision (FLV) in Latin America, especially in individuals under 50 years of age. In the present study, we retrospectively evaluated the medical records of 1393 consecutive subjects seen at a Brazilian tertiary rehabilitation service, from February 2009 to June 2016. We collected sociodemographic, clinical data, and information on optical aids and spectacle prescription. Subjects were divided into three age groups: 0 to 14 years old (children), 15 to 49 years old (young adults), and 50 years or older (older adults). The main etiologies leading to FLV in children were cerebral visual impairment (27.9%), ocular toxoplasmosis (8.2%), and retinopathy of prematurity (7.8%). In young adults, retinitis pigmentosa (7.4%) and cone/rod dystrophy (6.5%) were the most frequent, while in older adults, age-related macular degeneration (25.3%) and diabetic retinopathy (18.0%) were the leading causes. Our results indicate that preventable diseases are important causes of FLV in children in the area, and proper prenatal care could reduce their burden. The increasing life expectancy in Latin America and the diabetes epidemic are likely to increase the demand for affordable, people-centered rehabilitation centers, and their integration into health services should be planned accordingly.

Contact Lens Prescribing Trends for Keratoconus at an Academic Medical Center: Increased Utilization of Scleral Lenses for Severe Disease.

To describe contact lens prescription trends for patients with keratoconus. Demographics, corneal curvature, visual acuity, and type of contact lens prescribed were reviewed for all patients with keratoconus evaluated in the contact lens service in 2010 and 2020. There were 292 patients in 2010 and 217 in 2020. In 2010, 69% were using corneal gas-permeable lenses (GP), 16% soft toric, 13% hybrid, and 2% soft sphere with no scleral lens (SL). In 2020, 60% were using corneal GP, 22% SL, 12% soft toric, 5% hybrid, and 1% soft sphere. Mean log of minimum angle of resolution visual acuities with manifest refraction were (represented in mean [SD, range]) 0.42 (0.33, 0-1.3) in 2010 and 0.35 (0.33, 0-1.6) in 2020 improving to 0.19 (0.18, 0-1.3; P≤0.01) and 0.13 (0.14, 0-0.60; P<0.01) with contact lenses. Mean keratometry measurement in patients using SLs was 53.0 diopters (D) (9.9, 42.1-84.5), which was steeper than 46.6 D in patient's using all other lens types in 2010 and 2020 (3.9, 40.9-57.9; P<0.01). Scleral lens prescription increased during the past decade; however, corneal GP lenses remain the most frequent lens prescribed for patients with keratoconus in this cohort. Despite being prescribed for patients with the most advanced disease, SLs provide good visual acuity.