Spectacle Prescription Research Articles

Teleconsultation at a public ophthalmic teaching hospital during the COVID-19 pandemic.

To analyze teleconsultation at a public ophthalmic teaching hospital during the COVID-19 pandemic in Brazil. Medical records of patients who requested ophthalmological teleconsultation between June 2020 and March 2021 were reviewed. The main outcomes included demographic data, eye disease symptoms, hypothesized diagnosis, and management. Moreover, the results of a satisfaction survey administered after the consultation were analyzed. Medical records of a total of 161 patients were reviewed. The mean age was 45.98 ± 17.57 (8-90) years, and most were women (113, 70.20%). Only 57 (35.60%) of the patients had made previous follow-up visits to the hospital. The most frequent reason for consultation was the need for a new eyeglass prescription (73, 45.34%), followed by dry eye symptoms (16, 9.93%) and pterygium (13, 8.07%). Other reasons were the monitoring of previously diagnosed eye diseases, such as glaucoma, retinopathies, strabismus, and keratoconus. Regarding the satisfaction survey, 151 (93.78%) patients answered the online questionnaire. Most reported that they were satisfied with the teleconsultation (94.03%) and would participate in a future teleconsultation (90.06%). Teleconsultation could be widely used to assist patients in public ophthalmology healthcare and teaching hospitals. Even though new eyeglass prescriptions are a frequent reason for ophthalmological appointments, patients tend to be satisfied with teleconsultation, as it also provides guidance.

Assessment of risk factors in medical data using improved Binary Artificial Fish Swarm Algorithm with Classification upon Evaluation from F-Test

The objective of this research work is to effectively deploy improved Binary Artificial Fish Swarm optimization Algorithm (BAFSA) with the data classification techniques. The improvement has been made with accordance to the condition of visual scope and the movement of fish to update towards the central position and chasing behavior towards best point of movement has been modified among the given population. The experimental results show that feature selection by BAFSA and classification by Decision trees and Gaussian Naïve bayes algorithm provides an improved accuracy of about 89.6% for Pima Indian diabetic dataset, 91.1% for lenses dataset and 94.4% for heart disease dataset. Statistical analysis has also been made using Fisher’s F-Test for two sample variance and the selected risk factors such as glucose, insulin level, blood pressure for diabetics datasets, spectacle prescription, tear production rate for lenses dataset and trestbps, cholesterol level, thalach, chest pain type for heart disease dataset are found to be significant with R2<0.001 respectively.

Pattern of Ametropia, Presbyopia, and Barriers to the Uptake of Spectacles in Adult Patients Attending a General Hospital in Kaduna State.

Aim:The aim of the study was to assess the pattern of ametropia, presbyopia, and the barriers to the uptake of spectacles among adult patients attending Hajiya Gambo Sawaba General Hospital (HGSGH), Zaria, Nigeria.Materials and Methods:This study was a descriptive hospital-based study. The study population was selected by systematic sampling over a 3-month period (July–September, 2016). A questionnaire was administered for sociodemographic data, patients’ history, and refraction. Patients with visual acuity less than 6/12 or who required at least +1.00DS to read N8 were given spectacle prescriptions and assessed after 2 months to confirm if they purchased the spectacles.Results:Two hundred and nine patients were assessed: 124 (59.3%) females and 85 (40.7%) males. The age ranged from 18 to 75 years with a mean of 45.5. One hundred and seventy-five (83.7%) had ametropia, 100 (47.8%) had presbyopia, and patients having both were 66 (31.6%). Astigmatism was the most common ametropia, 118 (67.4%), followed by hypermetropic astigmatism 33 (18.9%) and myopia 24 (13.7%). Only 97 (46.6%) patients purchased their spectacles, and 92 of them were using their spectacles. One hundred and twelve (52.2%) patients did not buy their spectacles, with cost being most common barrier to the uptake of spectacles.Conclusion:There is a high burden of ametropia and presbyopia among patients attending HGSGH, Zaria. Cost of spectacles and ‘no felt need’ were found to affect spectacle uptake. Health information and availability of low-cost spectacles are important strategies in reducing the burden of uncorrected ametropia and presbyopia in Kaduna State.

Changes in Refractive and Optometric Findings During Pregnancy.

Background: Pregnancy-induced changes in the physiological responses during the gestational period can affect the eye. This study aimed to evaluate the effect of pregnancy on visual, refractive, vergence, and accommodative status. Methods: In this cross-sectional study, twenty-five healthy pregnant women with a mean age of 29±3.1 were examined. All of the subjects underwent comprehensive ophthalmologic examinations, including anterior segment and fundus examinations and tonometry. Refractive error was determined in each trimester using Autokeratometer. Furthermore, near the point of convergence (NPC), best-corrected visual acuity (BCVA), and near the point of accommodation (NPA) were measured. Data analysis was performed using SPSS version 22. To compare the data during pregnancy, repeated measures analysis of variance (ANOVA) was performed. Results: During pregnancy, in the right and left eye, spherical equivalent (SE) had a myopic shift from -0.13 to -0.35 D and +0.096 to -0.23 D, respectively (p=0.049 and p=0.020, respectively). Also, in the right and left eyes BCVA significantly decreased from -0.13 to 0.00 and -0.14 to 0.00 LogMAR, respectively (p=0.039 and p=0.045, respectively). NPA and NPC did not change statistically significantly during pregnancy (p=0.385, and p=0.801, respectively). Conclusion: Due to the unstable hormonal status, a myopic shift and decrease in BCVA occur during pregnancy. So, any change in their spectacle prescription, fitting of contact lenses, performing refractive surgeries, etc., during this period should be postponed.

Myopia: A Behavioral Approach for Prescribing and Vision Therapy

Myopia has reached serious epidemic proportions in many developed countries throughout the world, and is a public health issue with which the optometric profession is deeply concerned. Different clinical approaches are available to the optometrist for treatment of myopia. For the majority of patients, prescribing minus lenses to achieve 20/20 visual acuity at distance does little to prevent a patient from becoming more myopic or to improve vision function in the broadest sense, though it provides immediate improvement in distance visual acuity. A behavioral optometric clinical approach is presented in this paper to give the doctor a clear-cut strategy offering more alternatives to the patient with myopia. Employing this approach has the potential to prevent patients from developing myopia to levels higher than -2.00 diopters, reversing minus lens powers in patients that come to the optometrist already wearing a minus lens prescription, and reducing dependency on using minus lens prescriptions. Vision therapy is addressed as a procedure to improve a patient’s vision function in addition to visual acuity. Book retinoscopy is employed as a valuable technique to arrive at a training eyeglass prescription. At the completion of treatment, a patient typically improves in distance visual acuity, reduces minus lens powers, develops increased confidence in vision capabilities (with and without minus lens wear), develops an awareness and appreciation for additional aspects of vision such as space, forms, colors, patterns, periphery, and feels empowered that they have learned how to improve distance vision through self-initiated control.

Prediction of manifest refraction using machine learning ensemble models on wavefront aberrometry data

PurposeTo assess the performance of machine learning (ML) ensemble models for predicting patient subjective refraction (SR) using demographic factors, wavefront aberrometry data, and measurement quality related metrics taken with a low-cost portable autorefractor. MethodsFour ensemble models were evaluated for predicting individual power vectors (M, J0, and J45) corresponding to the eyeglass prescription of each patient. Those models were random forest regressor (RF), gradient boosting regressor (GB), extreme gradient boosting regressor (XGB), and a custom assembly model (ASB) that averages the first three models. Algorithms were trained on a dataset of 1244 samples and the predictive power was evaluated with 518 unseen samples. Variables used for the prediction were age, gender, Zernike coefficients up to 5th order, and pupil related metrics provided by the autorefractor. Agreement with SR was measured using Bland-Altman analysis, overall prediction error, and percentage of agreement between the ML predictions and subjective refractions for different thresholds (0.25 D, 0.5 D). ResultsAll models considerably outperformed the predictions from the autorefractor, while ASB obtained the best results. The accuracy of the predictions for each individual power vector component was substantially improved resulting in a ± 0.63 D, ±0.14D, and ±0.08 D reduction in the 95% limits of agreement of the error distribution for M, J0, and J45, respectively. The wavefront-aberrometry related variables had the biggest impact on the prediction, while demographic and measurement quality-related features showed a heterogeneous but consistent predictive value. ConclusionsThese results suggest that ML is effective for improving precision in predicting patient's SR from objective measurements taken with a low-cost portable device.

Knowledge of eyeglasses prescription required for ophthalmologist

Knowledge of eyeglasses prescription required for ophthalmologist

The Amount of Under-correction of the Initial Eyeglass Prescription for Children with Myopia

The Amount of Under-correction of the Initial Eyeglass Prescription for Children with Myopia

Selected visual parameters related to the working conditions of musicians

Professional musicians are required to practice playing instruments for long hours, which often exerts significant impact on their health. Attention should be given to the specificity of playing each instrument, including uncomfortable and sustained body position and repetitive movements causing long-term strain of certain parts of the body. The aim of this study was to evaluate the impact of long-term playing wind and string instruments on the visual system. Ninety male and female subjects aged 15 to 30 years were included in the study and divided into two groups: musicians (Msc) and non-musicians (nMsc). Significantly less subjects in the Msc group had properly corrected vision, wore optical prescription recommended by an ophthalmologist/optometrist, and/or underwent any eye examination at all in their lifetime, even though more subjects in this group experienced certain asthenopic symptoms. Also, accommodative amplitude got statistically worse under dim illumination conditions, accommodative facility was significantly different between musicians and non-musicians, although there were no differences between the groups when tested in bright illumination. None of the music stands used by the study subjects met the respective standards concerning uniform illumination rates. Playing string and wind instruments is a challenge for the visual system due to the forced body and head positions, and asymmetry between the visual plane and the plane of regard as well as non-uniform illumination in the working environment. However, conditions such as correct working distance and proper tilt of the music stand may be beneficial to the visual system. It is the role of optometrists to properly educate their patients about the importance of appropriate vision correction, especially in dim light and under adverse working conditions and to communicate the impact of such conditions on the visual system.

The impact of diabetes mellitus and hyperglycaemia on the refractive status of the eye

Purpose. Diabetes mellitus is a condition of considerable concern globally, which can affect the visual system in various ways, including changes to visual function, the integrity of the ocular surface and the retinal microcirculation. The aim of this article is to provide an overview on the perspectives around the relationship between diabetes and refractive status. Material and Methods. Narrative literature review. Results. The relationship between diabetes, hyperglycaemia and refractive error has been of interest to clinicians and researchers for more than a century. This review shows that research studies investigating the relationship have varied considerably in their design, methodology, their outcome measures used as well as their reported results. While some uncertainty remains, there is evidence that short-term, drastic changes in blood glucose levels affect the refractive status of human eyes leading to fluctuating and blurred vision. Conclusion. Patients starting glycaemic treatment or under- going adaptation to a new treatment regime may present with considerable refractive changes and visual complaints. Before considering the prescription of spectacle lenses, clinicians should ideally monitor patients in whom glycaemic control has been initiated or is being adjusted until a stabilisation of blood glucose levels has been confirmed. Keywords Diabetes, refraction, refractive error, variability

Measurement and Analysis of Whole-surface Power Distribution in Single Tilted Spectacle Lenses.

Face-form tilt spectacles are sometimes tilted such that the optical properties of the embedded prescription lenses and the lens power change. If the lens power is not plano, the vision quality of the wearer may be affected. This study aimed to measure the whole-surface power distributions of tilted spectacle lenses for different lens powers and tilt angles. Spherical spectacle lenses with a refractive index of 1.56 and powers of -4.00 D, -2.00 D, plano, +2.00 D, and +4.00 D were measured. Their whole-surface power distributions were measured at different tilt angles, up to 20°, using a commercially available Hartmann wavefront aberrometer. The measured data were limited within a 40-mm diameter and analyzed to obtain contour plots of the spherical equivalent (M) and astigmatism (J). The measured whole-surface power profiles of the nontilted lenses showed both M and J as being symmetrical and increasing outward up to -0.52 and +0.24 D, respectively, for the -4.00 D lens and +0.22 and +0.05 D, respectively, for the +4.00 D lens, corresponding to the spherical design. The profiles of the tilted lenses showed both M and J as unevenly increasing from the center to the peripheral area along the downward tilt direction; however, the plano lens exhibited no effect of tilt on both M and J. The powers at the optical center of the lens increased with tilt angle and lens power. The maximum differences for M and J at a 15° tilt angle in the -4.00 D lens were -2.46 and +1.43 D, respectively. Conversely, at a 17° tilt angle, the maximum differences in the +4.00 D lens were +0.96 D in M and +0.46 D in J. Tilt angle and lens power strongly affect the power profiles of tilted spectacle lenses.

Visual impairment among eye health workers in a tertiary eye centre in Ghana

To determine causes of visual impairment (VI) among staff of the Eye Centre at the Korle Bu Teaching Hospital. This was a cross-sectional study. The Eye Centre, Korle Bu Teaching Hospital (KBTH), from October 2016 to March 2017 on all consenting members of staff. Eighty-four (79.3%) of 106 consenting staff members participated in this study. A detailed history (demographic, ocular, medical co-morbid conditions), ocular examination and relevant diagnostic investigations were conducted. Interventions initiated included treatment for glaucoma, dry eye and allergic conjunctivitis and spectacles prescription for refractive errors. Prevalence of avoidable causes of VI (glaucoma, cataract, refractive errors). Secondary outcomes included prevalence of unavoidable causes of VI. Eighty-four (79.3%) members of staff participated in this study. Most of the participants were females, 54(64.3 %). Age ranged from 23 to 60 years with an average of 35.8±9.9 years (mean ± SD).Prevalence of VI was 9.5 % (8/84), all due to uncorrected refractive error. Other known causes of VI included open angle glaucoma in 12(14.3 %), macular scar of unknown cause, 1(1.2 %) and sutural cataract, 1(1.2 %) but were all visually insignificant. The prevalence of VI among the staff of the Eye Centre of the KBTH was 9.5 %, all due to refractive errors. Other known causes of avoidable visual impairment and blindness encountered were glaucoma (14.3 %), macular scar (1.2 %) and cataract (1.2 %), all asymptomatic. Routine eye screening should be part of periodic medical examination for employees. None declared.

Assessment of Risk Factors in Medical Data Using Improved Binary Artificial Fish Swarm Algorithm With Classification Upon Evaluation From F-Test

The objective of this research work is to effectively deploy improved Binary Artificial Fish Swarm optimization Algorithm (BAFSA) with the data classification techniques. The improvement has been made with accordance to the condition of visual scope and the movement of fish to update towards the central position and chasing behavior towards best point of movement has been modified among the given population. The experimental results show that feature selection by BAFSA and classification by Decision trees and Gaussian Naïve bayes algorithm provides an improved accuracy of about 89.6% for Pima Indian diabetic dataset, 91.1% for lenses dataset and 94.4% for heart disease dataset. Statistical analysis has also been made using Fisher’s F-Test for two sample variance and the selected risk factors such as glucose, insulin level, blood pressure for diabetics datasets, spectacle prescription, tear production rate for lenses dataset and trestbps, cholesterol level, thalach, chest pain type for heart disease dataset are found to be significant with R2<0.001 respectively.

Performance of a photoscreener in detecting accommodation spasm

ABSTRACT Clinical Relevance For a correct spectacle prescription, accommodation spasm should not be overlooked in the measurements made using an autorefractometer. Although this can be easily understood with cycloplegia, it is not practical. Therefore, investigating practical methods that can predict excess accommodation will be useful in clinical practice. Background To evaluate the performance of a photoscreener in detecting pseudo-myopia due to accommodation spasm and whether it eliminates the need for cycloplegia. Methods Study was conducted in Van Training and Research Hospital. The manifest refraction of the patients was measured using an by an autorefractometer followed by a photoscreener before cycloplegia. Cycloplegic refraction errors were detected using an autorefractometer. Patients with pseudo-myopia due to accommodation spasm were diagnosed by observing a significant hyperopic shift in cycloplegic autorefractometer values compared to the non-cycloplegic values and were included in study. Cycloplegic autorefractometer and non-cycloplegic photoscreener measurements were compared. Results The mean non-cycloplegic autorefractometer values were as follows: -−6.34 ± 1.29D, −0.42 ± 0.58D, and −6.55 ± 1.36D for spherical, cylindrical, and spherical equivalents, respectively. These values were 0.23 ± 0.63D, −0.21 ± 0.41D, and 0.11 ± 0.73D for cycloplegic autorefractometer measurements, respectively. Cycloplegic autorefractometer values showed a significant hyperopic shift of 6.57 ± 1.26D and 6.67 ± 1.34D for spherical and spherical equivalents, respectively, compared to non-cycloplegic values (p < 0.001 for both). There was no significant difference between non-cycloplegic photoscreener and cycloplegic autorefractometer measurements for spherical, cylindrical, and spherical equivalents (p = 0.126, p = 0.078, and p = 0.053, respectively). . There was agreement between the measurements in the Bland-Altman graph. Conclusion There was consistency between non-cycloplegic photoscreener and cycloplegic autorefractometer measurements in patients with pseudomyopia due to accommodation spasm. Therefore, photoscreener measurements can be a fast, practical, cost-effective examination method for screening these patients without the need for cycloplegia.

Accuracy and Repeatability of Internet-ordered Spectacle Lenses.

Both consumers and eye care practitioners need to know how well online optical vendors conform with the accepted standards for quality and safety. We found that almost 1 in 10 prescriptions failed to meet national standards, which is a significant improvement over previous studies. The purpose of this study was to assess the accuracy and repeatability of spectacle lens prescriptions ordered from a sample of online vendors. Spectacle lens prescriptions were ordered by paid participants with no optical training who were masked to the study objectives. The prescription powers ordered (sphere, cylinder, and axis) were statistically sampled from 1000 previously filled prescriptions. A total of 100 orders were placed with each of three online vendors that included a range of high- and low-powered single vision lenses and progressive addition lenses, and duplicate orders to assess repeatability. An independent certified testing laboratory was contracted to assess conformance with voluntary consensus standards (ANSI Z80.1-2015) and Food and Drug Administration drop-ball safety testing. Lenses not meeting these standards were counted as failures. The overall failure rates for the three vendors were 11.2 ± 3.2% (vendor A), 8.0 ± 2.7% (vendor B), and 8.2 ± 2.8% (vendor C). The repeatability for 20 prescriptions ordered five times from each vendor was high, with correlation coefficients greater than 90%. There were no observed lens impact failures. Almost 1 in 10 spectacle lens prescriptions ordered from three online vendors failed to meet national standards for optical quality. Additional studies are needed to assess eyewear ordered online for other important patient-specific variables that can influence visual performance and ultimate acceptability of prescription eyewear, such as lens placement relative to the visual axis, frame fit, and cosmetic acceptability.

Contact Lens Prescribing in Canada 2006

A questionnaire was used to identify current preferences for contact lens prescribing in Canada. Practitioners were asked to submit information on the first ten patients fit­ted with contact lenses immediately after receipt of the survey; 151 completed questionnaires were returned, detailing contact lens fits to 1,421 patients. The results indicated that of the patients fitted with contact lenses, the majority were prescribed soft lenses. The preferred modality was monthly planned replacement. Over 80% of the soft lens fits were with either silicone hydrogel or mid-water content materials, with an even split between the two material options. Of the rigid lens fits the ma­jority were for daily wear. The overnight wear of rigid lenses appears to be for the practice of orthokeratology. Practitioners are recommending multipurpose solutions for the majority of their soft lens patients (91%).

Control of Glare for VDT Operators

The widespread use of video display terminals (VDTs) in offices has been accompanied by many complaints of visual problems. A recent study by the Canadian Labour Congress on vision problems among 2,300 office workers showed that VDT operators report twice as many vision problems and require more frequent changes in lens prescription. Visual complaints have stimulated research into new means of relieving the discomfort experienced by VDT operators.

How to Improve Success Rate of Rigid Gas Permeable Lens Prescription

A rigid gas permeable (RGP) lens is good for correcting corneal astigmatism without inducing corneal hypoxia. However, despite the optical advantage of the RGP lens for correcting visual acuity, there may be circumstances in which a patient may choose not to wear the RGP lens. For example, because the RGP lens is smaller than the cornea, it may cause a foreign body sensation due to lens movement and blurring, especially at night. Thus, the success of the RPG lens prescription depends on the selection of the proper candidates and lenses, with appropriate fitting and follow-up management by a doctor.

Practice of Eye Checks among Medical Doctors in South-East Nigeria

Visual impairment greatly affects one’s quality of life. The number of persons with visual impairment and blindness in the world is on the increase. Eye screening allows for early detection of sight-threatening diseases and timely intervention could be sight-saving. &#x0D; Aim: To determine the practice of eye checks and identify the factors that affect periodic eye checks among medical doctors in south-east Nigeria.&#x0D; Methodology: This study was a descriptive, cross-sectional study conducted among practicing medical doctors in private and public hospitals in Anambra State Nigeria, using a self-administered semi-structured questionnaire. Information obtained from the participants included the sociodemographics data, type and duration of practice, presence of any medical and/or ocular condition, family history of eye diseases, history of use of spectacles, practice of eye check and interval of eye check, factors affecting the practice of eye check, and ways of promoting regular eye check. Data obtained were analysed using the Statistical Package for the Social Sciences version 23. Statistical significance was set at p˂0.05. &#x0D; Results: One hundred and eighty-seven practicing medical doctors were interviewed. There were 123 (65.8%) males and 64 (34.2%) females. Their ages ranged from 24 to 80 years, with a mean age of 44.81 ± 12.73 years. The mean duration of professional practice was 18.16 ± 11.9 years. Majority, 124 (66.3%) works in government-owned hospitals. Among the study participants, 93(49.7%) doctors had been diagnosed with different ocular diseases; 99(52.9%) had a family history of ocular problems; 94(50.3%) had used prescription lenses; and 51(27.3%) had medical conditions. One hundred and twelve (59.9%) had undergone at least eye examinations once, of which 54(48.2%) had their last eye examination over 5 years ago. The prevalence of eye check was 59.9% (95%CI: 52.9 – 66.9%). Eye checks were significantly associated with medical practice of over 20 years (P=0.030), working in a private practice (P=0.001), having eye diseases such as cataract (P=0.006), refractive error (P˂0.001), presbyopia (P˂0.001), and use of prescription spectacles (P˂0.001). ‘Belief of not having eye problems’ and ‘No time’ which accounted for 58.7% and 24.0% respectively were the commonest reasons for not regularly having eye examinations. &#x0D; Conclusion: Poor attitude to periodic eye examinations was seen in medical doctors in south east Nigeria.

Optical and visual quality of real intraocular lenses physically projected on the patient's eye.

Visual simulators aim at evaluating vision with ophthalmic corrections prior to prescription or implantation of intraocular lenses (IOLs) in the patient's eye. In the present study, we present the design, implementation, and validation of a new IOL-in-cuvette channel in an Adaptive Optics visual simulator, which provides an alternative channel for pre-operative simulation of vision with IOLs. The IOL is projected on the pupil's plane of the subject by using a Rassow system. A second lens, the Rassow lens, compensates for an IOL of 20 D while other powers can be corrected with a Badal system within a 5 D range. The new channel was evaluated by through-focus (TF) optical quality in an artificial eye on bench, and by TF visual acuity in patients, with various IOL designs (monofocal, diffractive trifocal, and refractive extended depth of focus).