Lens Fitting Research Articles

Patient-Centered Innovation: Involving Patients in Open Social Innovation.

Involving patients in the health-care delivery innovation has many benefits. Open social innovation (OSI) presents a fitting lens to examine and advance patient engagement in innovation. OSI offers a participatory approach to innovation, in which diverse groups of participants collaboratively generate ideas and scale solutions on complex social challenges. This study: (1) describes a pilot application of OSI, in which individuals serving on a hospital's patients and family advisory councils (PFACs) were invited to participate in an innovation contest; and (2) explores the extent to which patients' beliefs about their role in innovation relate to their participation in the contest. We conducted an innovation contest that invited PFAC members to share ideas that would improve patient experiences and then vote on and select the ideas that they wanted to see move forward. We measured patients' beliefs about their role in innovation in a survey before the contest. Twenty individuals submitted 27 ideas. Patients who expressed preference for more involvement in innovation were more likely to participate. Using OSI may help expand patient engagement in innovation, particularly among those who want to be more involved but do not feel authorized to voice ideas in traditional advisory committees. OSI spurred collaboration among patients, clinicians, quality improvement staff, hospital administrators, and other stakeholders in idea generation, elaboration, and implementation. More experimentation and research are needed to understand how OSI can be leveraged to capture patients' voice and incorporate them in care delivery innovation.

Development of a Machine-Learning-Based Tool for Overnight Orthokeratology Lens Fitting.

Orthokeratology (ortho-K) is widely used to control myopia. Overnight ortho-K lens fitting with the selection of appropriate parameters is an important technique for achieving successful reductions in myopic refractive error. In this study, we developed a machine-learning model that could select ortho-K lens parameters at an expert level. Machine-learning models were established to predict the optimal ortho-K parameters, including toric lens option (toric or non-toric), overall diameter (OAD; 10.5 or 11.0 mm), base curve (BC), return zone depth (RZD), landing zone angle (LZA), and lens sagittal depth (LensSag). The analysis included 547 eyes of 297 Korean adolescents with myopia or astigmatism. The dataset was randomly divided into training (80%, n = 437 eyes) and validation (20%, n = 110 eyes) sets at the patient level. The model was trained based on clinical ortho-K lens fitting performed by highly experienced experts and ophthalmic measurements. The final machine-learning models showed accuracies of 92.7% and 86.4% for predicting the toric lens option and OAD, respectively. The mean absolute errors for the BC, RZD, LZA, and LensSag predictions were 0.052 mm, 2.727 µm, 0.118°, and 5.215 µm, respectively. The machine-learning model outperformed the manufacturer's conventional initial lens selector in predicting BC and RZD. We developed an expert-level machine-learning-based model for determining comprehensive ortho-K lens parameters. We also created a web-based application. This model may provide more accurate fitting parameters for lenses than those of conventional calculations, thus reducing the need to rely on trial and error.

Experiences of keratoconus patients attending public eye care facilities in South Africa.

Keratoconus (KC) is a progressive condition that usually affects young persons between their first and fourth decades. Myopia and irregular astigmatism are the common presentations which are proceeded by corneal steepening and thinning. Keratoconus is a progressive ectasia of the cornea that presents bilaterally, although often asymmetrical. To explore the experiences of KC patients attending public eye care facilities in Capricorn District of Limpopo province. Capricorn District, Limpopo province, South Africa. Descriptive qualitative phenomenology approach was used in the study to explore the lived experiences of patients diagnosed with KC, attending public eye care facilities. Purposive sampling was used to select 16 patients who were diagnosed with KC and referred for contact lens fitting. Data were collected through face-to-face, one-on-one interviews. Patients reported to have developed gradual vision loss which worsened when they grew older. There was lack of knowledge of KC amongst patients and this was exacerbated by limited health literacy and vocabulary barriers. Patients had difficulty performing daily activities where some had dropped out of school while others worked at a slower pace and reduced working distances. Patients with KC received inadequate information on their condition due to limited health literacy and vocabulary barriers. Programmes to promote practitioner and patient education are required to improve the perceived service level provided to KC patients.Contribution: The findings of this study will assist to improve the experiences of KC patients on perceived service quality received from public facilities.

Corneal Rigid Gas Permeable Contact Lens in Corneal Scarring: a Case Report

Introduction : Corneal scarring is part of corneal wound healing response to injury, surgery, or infection to the cornea. Corneal scarring causes significant visual reduction. This case report highlights visual acuity (VA) improvement in patient with corneal scarring following rigid glass permeable contact lens (RGP-CL)
 Case Illustration : A 25 year-old male presented blurry vision in right eye (RE) due to trauma. His VA was 3/60 on RE and 6/6 on left eye (LE). The best corrected visual acuity (BCVA) of RE was 6/45 (S-1.25 C-5.00 X 180°). Slit lamp examination of RE showed corneal scarring in central area and deep neovascularization. Keratometry readings obtained 39.50D (8.48mm) at 170 degree and vertical curvature of 44.00D (7.68mm) at 80 degree, with markedly irregular mires of RE. A trial fitting was performed for RE by using tisilfocon A lens with base curve of 8.30 mm, power S-4.00D and diameter 9.20 mm. The over-refraction with trial lens obtained a total refractive error of S-6.00 with cylindrical correction neutralize with RGP. The achieved BCVA by over-refraction was 6/45 with comfortable fit.
 Discussion : Rigid permeable lens (RGP) is an option in dealing with irregular astigmatism due to corneal scarring. The RGP fitting works best especially when the corneal scarring is not in the center of visual pathway. Rigid lens works by providing tear-lens power and creating smooth surface to neutralize the irregular cornea. Good RGP-CL fitting could help patient with corneal carring gain better VA.
 Conclusion : Good rigid permeable contact lens fitting could help patients with corneal scarring gain better VA.

The Comparison of Visual Acuity between Spectacles and Rigid Gas Permeable (RGP) Group in Myopia Patients

Introduction & Objectives : The prevalence of myopia has approximately doubled in the past three decades, with rates of 70–87% among populations of school children and young adults in Asia. Approaches to treating myopia include spectacles and Rigid Gas Permeable (RGP) contact lenses. RGP has become a new "preference" because it is more comfortable and provides a more aesthetic look. This study aims to determine which method is better for correcting visual acuity in myopia patients.
 Methods : This cross-sectional study analyzed the outcomes and exposures measured at the same time. The sample included myopia patients (based on spherical equivalent) who underwent RGP contact lens fitting in the refraction outpatient clinic of M Djamil Hospital from January 2021 to December 2022. The samples were selected based on inclusion and exclusion criteria. The collected data included gender, age, and best-corrected visual acuity using spectacles and RGP.
 Results : Forty-three patients were eligible as the sample in this study. Most of the subjects were women (62.8%), and the mean age was 23.58 years old. The median LogMAR for the RGP group was lower than the spectacles group (0.00:0.10 on both eyes). Statistical analyses found a significant visual acuity improvement in the RGP group compared to the spectacles group in both the right and left eyes (p = 0.014 and p = 0.005, respectively (p < 0.05)).
 Conclusion : The use of RGP provides significantly better visual acuity in correcting myopia than spectacles. Myopia is more frequently found in young women.

Chinese expert consensus on the diagnosis and treatment of contact lens-associated dry eye (2024)

The number of contact lens wearers in China is increasing rapidly. Long-term contact lens wearing may induce or exacerbate tear film instability, and consequently affect the visual quality, ocular surface safety, and compliance of the wearers. To promote the safety and effectiveness of contact lens fitting, and to improve the visual quality and satisfaction of contact lens wearers, the Society of Contact Lens Safety Monitoring & Vision Health of Chinese Health Association has targeted to develop an expert consensus on the diagnosis and treatment of contact lens-associated dry eye. By referring to relevant literature and summarizing clinical experience, the clinical experts in corneal disease, pediatric ophthalmology and optometry have made repeated discussions to form this consensus, including the definition, pathological mechanisms, influencing factors, evaluation, prevention and treatment of contact lens-associated dry eye, for the reference of optometrists and ophthalmologists.

FEA-Based Stress-Strain Barometers as Forecasters for Corneal Refractive Power Change in Orthokeratology.

To improve the effectivity of patient-specific finite element analysis (FEA) to predict refractive power change (RPC) in rigid Ortho-K contact lens fitting. Novel eyelid boundary detection is introduced to the FEA model to better model the effects of the lid on lens performance, and stress and strain outcomes are investigated to identify the most effective FEA components to use in modelling. The current study utilises fully anonymised records of 249 eyes, 132 right eyes, and 117 left eyes from subjects aged 14.1 ± 4.0 years on average (range 9 to 38 years), which were selected for secondary analysis processing. A set of custom-built MATLAB codes was built to automate the process from reading Medmont E300 height and distance files to processing and displaying FEA stress and strain outcomes. Measurements from before and after contact lens wear were handled to obtain the corneal surface change in shape and power. Tangential refractive power maps were constructed from which changes in refractive power pre- and post-Ortho-K wear were determined as the refractive power change (RPC). A total of 249 patient-specific FEA with innovative eyelid boundary detection and 3D construction analyses were automatically built and run for every anterior eye and lens combination while the lens was located in its clinically detected position. Maps of four stress components: contact pressure, Mises stress, pressure, and maximum principal stress were created in addition to maximum principal logarithmic strain maps. Stress and strain components were compared to the clinical RPC maps using the two-dimensional (2D) normalised cross-correlation and structural similarity (SSIM) index measure. On the one hand, the maximum principal logarithmic strain recorded the highest moderate 2D cross-correlation area of 8.6 ± 10.3%, and contact pressure recorded the lowest area of 6.6 ± 9%. Mises stress recorded the second highest moderate 2D cross-correlation area with 8.3 ± 10.4%. On the other hand, when the SSIM index was used to compare the areas that were most similar to the clinical RPC, maximum principal stress was the most similar, with an average strong similarity percentage area of 26.5 ± 3.3%, and contact pressure was the least strong similarity area of 10.3 ± 7.3%. Regarding the moderate similarity areas, all components were recorded at around 34.4% similarity area except the contact pressure, which was down to 32.7 ± 5.8%. FEA is an increasingly effective tool in being able to predict the refractive outcome of Ortho-K treatment. Its accuracy depends on identifying which clinical and modelling metrics contribute to the most accurate prediction of RPC with minimal ocular complications. In terms of clinical metrics, age, Intra-ocular pressure (IOP), central corneal thickness (CCT), surface topography, lens decentration and the 3D eyelid effect are all important for effective modelling. In terms of FEA components, maximum principal stress was found to be the best FEA barometer that can be used to predict the performance of Ortho-K lenses. In contrast, contact pressure provided the worst stress performance. In terms of strain, the maximum principal logarithmic strain was an effective strain barometer.

A Thrice-Told Tale of Japanese Staffrooms and a Transformative Journey in Searching for East Asia as Method

Purpose This study aims to search for fitting lenses to view and interpret teacher learning in a Japanese secondary school teacher staffroom and capture the reconstituting of researcher subjectivities in this process. Design/Approach/Methods A narrative approach chronically documents the findings and use of the lenses in analyzing the staffroom daily interactions and traces the journey of transformation in our researcher subjectivities. Findings The telling of a Japanese staffroom (shokuinshitsu) as a thrice-told tale under the three lenses—cultural-historic activity theory, contextualism, and intimacy orientation—each uncovers a unique interpretation of the learning going on in the daily life of the Japanese staffroom. While complementary, Western-lenses are found to be unable to explain the nature of the everyday practices in the staffroom formed under the worldviews and ethics of East Asia. Our critical examination of the major academic encounters involved in the past two decades illuminates the complex dynamism behind our research perspectives, awakens us to the dominance of Western-centralism in our researcher subjectivities, transforms our worldviews, and returns us to our cultural roots to build alternative frames of reference as East Asia as Method. Originality/Value This study not only uniquely demonstrates what decentered, alternative, and diversified frames of reference would look like in studying East Asian practices but also what it would take for scholars to move toward East Asia as Method. Additionally, going beyond the three lenses, it contributes to our understanding of how space (staffroom as an entity) mediates forming of the character of those who are dwellers of the shokuinshitsu.

Evaluation of the corneal topography based on deep learning.

The current study designed a unique type of corneal topography evaluation method based on deep learning and traditional image processing algorithms. The type of corneal topography of patients was evaluated through the segmentation of important medical zones and the calculation of relevant medical indicators of orthokeratology (OK) lenses. The clinical data of 1,302 myopic subjects was collected retrospectively. A series of neural network-based U-Net was used to segment the pupil and the treatment zone in the corneal topography, and the decentration, effective defocusing contact range, and other indicators were calculated according to the image processing algorithm. The type of corneal topography was evaluated according to the evaluation criteria given by the optometrist. Finally, the method described in this article was used to evaluate the type of corneal topography and compare it with the type classified by the optometrist. When the important medical zones in the corneal topography were segmented, the precision and recall of the treatment zone reached 0.9587 and 0.9459, respectively, and the precision and recall of the pupil reached 0.9771 and 0.9712. Finally, the method described in this article was used to evaluate the type of corneal topography. When the reviewed findings based on deep learning and image processing algorithms were compared to the type of corneal topography marked by the professional optometrist, they demonstrated high accuracy with more than 98%. The current study provided an effective and accurate deep learning algorithm to evaluate the type of corneal topography. The deep learning algorithm played an auxiliary role in the OK lens fitting, which could help optometrists select the parameters of OK lenses effectively.

Comparative analysis of clinical and functional parameters in patients with stable stage II-III keratoconus after implantation of corneal segments and fitting of scleral rigid contact lenses

This study compares the effect of implantation of intrastromal corneal ring segment (ICRS) and fitting of individual scleral rigid contact lenses (RCLs) on visual functions in patients with stage II-III KC after previously performed corneal collagen cross-linking. The Helmholtz National Medical Research Center of Eye Diseases examined and treated 34 patients (69 eyes) aged 18 to 33 years with stage II-III KC. The study included patients who had previously undergone standard corneal collagen cross-linking. Depending on the type of optical correction, the patients were divided into two groups: patients in group 1 underwent ICRS implantation using a femtosecond laser; patients in group 2 were fitted with individual scleral RCLs. Improvement in clinical and functional parameters was observed in both groups. A higher clinical and functional result was achieved in group 2. For patients with stable stage II-III KC, it is advisable to recommend fitting of individual scleral RCLs for visual rehabilitation.

Fitting RPG Progressive Bitoric Lenses after Bilateral Glaucoma Surgery

Glaucoma is a group of eye diseases which result in damage to the optic nerve and vision loss. Glaucoma can be divided in two groups’ open-angle and closed-angle. The importance in glaucoma disease is to treat it early because vision loss from this pathology, once it has occurred, is permanent. The main risk of factors for glaucoma includes increased pressure in the eye, a family history of the condition and high blood pressure . Generally, it is possible to treat glaucoma with laser and this treatment may be affective in both open-angle and closed-angle. A number of types of glaucoma surgeries may be used in people who do not sufficiently respond to other measure and treatment of closed-angle glaucoma is a medical emergency. After the laser treatment, if the ophthalmologist gives permission, it is possible to fit contact lenses to achieve better vision or correct patients with spectacles. This case report shows the fitting of rigid gas permeable progressive bitoric lenses after laser treatment because visual acuity achieved with spectacles was not good. Due to the intervention and patient needs, it was not possible to fit a scleral or hybrid lens.

Evaluation of changes in corneal biomechanics after orthokeratology using Corvis ST

PurposeTo investigate the alterations in corneal biomechanical metrics induced by orthokeratology (ortho-k) using Corvis ST and to determine the factors influencing these changes. MethodA prospective observational study was conducted to analyze various Corvis ST parameters in 32 children with low to moderate myopia who successfully underwent ortho-k lens fitting. Corneal biomechanical measurements via Corvis ST were acquired at six distinct time points: baseline (pre) and 2 h (pos2h), 6 h (pos6h), and 10 h (pos10h) following the removal of the first overnight wear ortho-k, one week (pos1w) and one month (pos1m) subsequent to the initiation of ortho-k. ResultSignificant differences were observed in Corvis ST Biomechanical parameters DAR2, IIR, CBI, and cCBI post ortho-k intervention. The integration of covariates (CCT, SimK, and bIOP) mitigated the differences in DAR2, IIR, and cCBI, but not in CBI. Initially, the stiffness parameter at first applanation, SP-A1, did not demonstrate significant variations, but after adjusting for covariates, noticeable differences over time were observed. The Stress-Strain Indeces, SSIv1 and SSIv2, did not manifest considerable changes over time, irrespective of the adjustment for covariates. No significant disparities were identified among different ortho-k lens brands. ConclusionCorneal biomechanics remained consistent throughout the one-month period of ortho-k lens wear. The observed changes in Corvis ST parameters subsequent ortho-k are primarily attributable to alterations in corneal pachymetry and morphology, rather than actual alterations in corneal biomechanics. The stability of corneal biomechanics post ortho-k treatment suggests the safety of this approach for adolescents from a corneal biomechanics perspective.

Lens Checking: How Eye Care Practitioners Verify and Inspect Rigid Contact Lenses

Purpose. The primary focus of this article is to explore the critical aspects of verifying and inspecting RGP contact lens parameters in clinical practice. The verification process is essential to ensure that patients receive lenses with accurate and optimal parameters, thus improving their visual experi- ence and comfort. The article delves into the methods and instruments available to eye care practitioners for verifying key parameters, including back surface radii, total lens diam- eter, lens power, lens thickness, blends, and surface quality. Material and Methods. The discussion centers on the tech- niques and tools employed in the verification and inspection of RGP contact lens parameters. It emphasizes the signifi- cance of maintaining a clean and controlled environment for these assessments. Calibration and error minimization strate- gies are highlighted to enhance measurement accuracy. The article provides insights into device-specific measurements and the importance of averaging measurements to mitigate deviations. Results. The article outlines various procedures for verifying the essential parameters of RGP contact lenses. It covers methods for checking back surface radii, including the use of radiuscopes, keratometers, and corneal topographers. Verifi- cation of lens diameter is detailed with V-shaped measuring gauges, measuring magnifiers, and projection magnifiers. Lens power verification is explored through lensmeters and specialized lensmeter calibration techniques. Finally, the measurement of lens thickness, the inspection of lens edges, and the evaluation of surface quality and blends between different lens zones are addressed. Conclusion. This article underscores the significance of thorough verification and inspection of RGP contact lens parameters in clinical practice. These essential steps ensure that patients receive lenses that meet their specific needs, contributing to improved visual acuity, comfort, and overall ocular health. Eye care practitioners should check their pa- tients’ RGP contact lenses according to the ordered param- eters. By following the described methods and employing appropriate instruments, the fitting and prescribing of rigid gas-permeable contact lenses can be enhanced. Keywords Rigid gas-permeable contact lenses, RGP contact lenses, specifications and tolerances for rigid contact lens parameters, verification and inspection of RGP contact lenses, lens checking

Impact of Symblepharon Management With Ocular Surface Reconstruction on Scleral Lens Fitting in Eyes With Chronic Cicatrizing Conjunctivitis and Keratopathy.

The aim of this study was to describe the importance of symblepharon release with ocular surface reconstruction (OSR) for optimal fitting of scleral contact lenses (SCLs) in eyes with chronic cicatrizing conjunctivitis (CCC) and keratopathy. This retrospective study included 32 eyes with CCC and keratopathy with symblepharon which underwent symblepharon release with OSR and were fitted with SCLs. The primary outcome measure was the improvement in best-corrected visual acuity with SCL wear. A total of 32 eyes of 29 patients (66% men) with a median age of 30.5 years were included. The common causes of CCC were Stevens-Johnson syndrome (66%) and ocular burns (16%). The most common location of symblepharon was superior (59%) with limbal involvement in most eyes (94%). Symblepharon release was combined with mucous membrane grafting (63%), amniotic membrane grafting (31%), or conjunctival autografting (6%). The median interval between symblepharon release with OSR and SCL trial was 15 weeks [interquartile range (IQR): 6-24]. The median best-corrected visual acuity improved from logMAR 1.5 (IQR: 1.2-1.8) to logMAR 1.2 (IQR: 0.6-1.4) with SCLs after symblepharon release with OSR ( P < 0.001). The median diameter of the SCL used was 15 mm (IQR: 15-16), with a median base curve of 7.9 mm (IQR: 7.9-8). Symblepharon recurrence was noted in 70% of eyes that underwent amniotic membrane grafting; no recurrence was seen with mucous membrane grafting or conjunctival autografting. In eyes with CCC with keratopathy and symblepharon, visual rehabilitation is possible with SCLs after symblepharon release with OSR without having to resort to a penetrating corneal procedure.

The alterations in ocular biometric parameters following short-term discontinuation of long-term orthokeratology and prior to subsequent lens fitting: a preliminary study

Purpose To investigate the alterations in biometric parameters among Chinese adolescents over an extended period of wearing orthokeratology lenses, as well as the subsequent changes after a one-month cessation of lens usage prior to the secondary lens fitting. Methods Twenty-four myopic patients aged 7–14 were enrolled in this 37-month prospective observational study. Ocular biometric parameters were measured in the study. Ocular biometric parameters were assessed, and the utilization of Generalized Estimating Equations (GEE) was employed in the analysis to address the correlation between the two eyes of each participant. Results The axial length (AL) increased by 0.55 mm after 36 months of lens wearing and further increased to 0.62 mm at the 37-month follow-up compared to the initial measurement. The differences in AL elongation per month between the 37-month time point and the 12-, 24-, and 36-month marks of lens wearing were found to be statistically significant (p12-month = 0.001; p24-month = 0.003; p36-month = 0.001). Following the cessation of lens wear for 1 month, there was no significant complete recovery observed in the flat and steep keratometry values. However, the intraocular pressure and anterior chamber depth returned to their baseline levels. Conclusions The AL elongation undergoes alterations during temporary discontinuation of lenses, with the flat and steep keratometry measurements remaining significantly flatter compared to the baseline. However, the intraocular pressure and anterior chamber depth return to their initial levels after one month of lens cessation.

Comparison of the clinical efficacy of orthokeratology and 0.01% atropine for retardation of myopia progression in myopic children

ObjectiveTo compare the clinical efficacy of orthokeratology (ortho-k) and 0.01% atropine for retardation of myopia progression in myopic children. MethodsThis was a retrospective cohort study. A total of 282 patients, aged 8–17 years, were enrolled, including 100 children treated with ortho-k, 84 with 0.01% atropine, and 98 with single-vision spectacles. During the follow-up of 1 year, ortho-k wearers were examined at 1 day, 1 week, 1 month, 3 months after treatment, and thereafter every 3 months, while the others were examined every 3 months by measurements of uncorrected vision, intraocular pressure, refractive power, slit-lamp microscopy, corneal topography, and the lens fitting when necessary. The axial length was measured every 6 months. ResultsPatients with ortho-k had stable uncorrected vision after 1 month of lens wear, all reaching 0 logMAR. The annual axial elongation was 0.23 ± 0.19 mm, 0.22 ± 0.20 mm, and 0.39 ± 0.27 mm in the ortho-k, atropine, and spectacle groups, respectively, with significant difference (F = 23.251, P = 0.000). The axial length was delayed to increase by 41.03% and 43.59% within a year in patients with ortho-k and atropine, respectively, as compared to patients with spectacles (F = 0.006, P = 0.936). The elongation was ≤ 0.3 mm in 69.0% and 66.7% of patients in the two groups, respectively, versus 38.8% in the spectacle group (χ2 = 17.251, P = 0.000). During the follow-up, the rate of corneal staining was 11.0% and 2.0% in the ortho-k and spectacle groups, respectively (χ2 = 8.076, P = 0.003). The use of atropine did not increase corneal staining, but the incidence of related photophobia was 4.8%. No other serious complications were observed. ConclusionOrtho-k lenses and 0.01% atropine can achieve similar efficacy of myopia retardation, which was significantly better than that obtained with single-vision spectacles, in myopic children. The risk of corneal staining after ortho-k wear may be slightly higher than that with spectacles, but could be well controlled.

Effectiveness of toric soft contact lenses for vision correction in patients with different degrees of astigmatism: a real-world study.

To assess the visual correction of patients with different degrees of astigmatism with toric soft contact lenses (TSC). It was a real-world study with prospective and single-arm design. A total of 384 patients with astigmatism who came for TSC fitting and alignment from November 2022 to January 2023 were included. According to the difference in astigmatism, patients were divided into groups A (cylinder degree: -0.75 to -0.50 D), B (cylinder degree: -1.75 to -1.00 D) and C (cylinder degree ≤ -2.00 D), and followed up on the day of wear, 1wk, 1 and 3mo, mainly to observe visual acuity, refraction, lens fit, visual quality and comfort at 1wk after wear. The visual acuity success rate and the overall success rate of the fitting were evaluation indicators (taking into account the four dimensions of visual acuity, fitting, quality of vision and comfort). The visual acuity success rate was calculated by taking "corrected visual acuity with contact lenses is no less than 1 line or better than best spectacle-corrected visual acuity" (i.e. corrected visual acuity with contact lenses is 1 line below, equal to, one line above or more than best spectacle-corrected visual acuity) as the criterion for visual success, and the the overall success rate of the fitting was calculated by using the comprehensive indicators (visual acuity, fit, visual quality, comfort) to meet certain conditions as the judgment criteria for successful fitting. After 1wk of wearing TSC, the visual acuity success rates of patients were 100% (207/207), 98.58% (139/141) and 97.22% (35/36) in the three groups, respectively, with residual cylinder closed to 0. The acceptability of the lens fitting was over 95%; the incidence of adverse visual symptoms was within 10% and the comfort acceptability was over 97%. The overall success rate of fitting for patients with high, medium and low astigmatism was 93.72% (194/207), 90.78% (128/141) and 88.89% (32/36), respectively. TSC (model: G&G POP·CT) are effective in correcting astigmatism in patients with different degrees of astigmatism.

SWOT analysis of ortho-K practice in India

PurposeOrthokeratology (ortho-K) has been well established as a methodology for myopia correction and control its progression. A SWOT analysis serves as a strategic planning tool for intervention hence the purpose of this study to establish and implement ortho-K practice in India. MethodThe study was conducted between December 2020 and June 2021. A prospective questionnaire-based study was conducted to elicit the responses in the SWOT study. Based on focus group discussion a set of five statements under strengths, weaknesses, opportunities and threats were identified. These were closed ended questions were based on a 5-point likert scale. The Content Validation Index (CVI) was computed for each item taking those answers relevant with a score of three and four on the Likert scale and omitting those with a score of one and two on the Likert scale as non-relevant. ResultsStrengths: ‘Ortho-K is an excellent option for myopia control’ was agreed by more than 50% of respondents. 67% of respondents agreed that advanced topographers has made ortho-K lens fitting easier. Weakness: More than 60% agreed that Ortho-K practice involves investment in instrumentation like topographers and trial lenses. 50% agreed that due to multiple follow up patients may be lost to follow up. Opportunity: ‘Pandemic has necessitated the need for optometrists to explore myopia control options such as ortho-K’ was agreed by more than 50%. Threats: ‘Reluctance from adults and parents to try overnight contact lenses for myopia correction/control’ was agreed by more than 50% of respondents. 62% agreed that atropine is perceived as an effective myopia control option by majority of the Indian ophthalmologists. ConclusionOrtho-K as an emerging modality for Myopia management in India through SWOT analysis, allows practitioners as well as CL industry to approach Ortho-K appropriately with novel designs and practice patterns that suits the market needs.

Medmont Meridia™: Much More Than a Corneal Topographer.

In recent years, advanced diagnostic instruments have become widely available in optometric practices, offering various functions that optimize clinical information gathering. This article focuses on the Medmont Meridia™, a state-of-the-art multipurpose diagnostic device with corneal topography and cutting-edge features. Corneal topography is pivotal in the early diagnosis of corneal disorders, determining baseline ocular surface assessment, helping in contact lens fitting, and monitoring ocular health over time. The Medmont Meridia boasts Placido-disc-based imaging with extensive corneal coverage. Furthermore, the Meridia accurately measures the horizontal visible iris diameter, pupil diameter, and palpebral fissure width, which assists in making contact lens parameter decisions. Additionally, it offers sagittal height data for scleral lens design and first lens selection, streamlining the fitting process. Beyond its topography capabilities, the Meridia excels as a comprehensive dry eye assessment tool. With features like tear meniscus height, tear film surface quality, and meibography capabilities, it aids in diagnosing dry eye and monitoring its progression. The device also provides customizable dry eye reports with integrated grading scales and questionnaires, making dry eye management, patient education, and compliance more accessible. In conclusion, the Medmont Meridia consolidates a multitude of examination tools in a single instrument, enhancing practice efficiency and elevating patient care and communication. Its versatility and accuracy make it an invaluable asset in optometric practices worldwide.

Epithelial and stromal thickness profile and lens decentration in myopic orthokeratology

PurposeTo study topographic epithelial and total corneal thickness changes in myopic subjects undergoing successful orthokeratology treatment in connection with the objective assessment of contact lens decentration. MethodsA prospective-observational and non-randomized study in 32 Caucasian myopic eyes undergoing Ortho-k for 3 months. Total, epithelial, and stromal thicknesses were studied before and after Ortho-k treatment, using optical coherence tomography with anterior segment application software. Central, paracentral, and mid-peripheral values are taken along 8 semi-meridians. ResultsThe central average total corneal thickness was 4.72 ± 1.04 μm thinner after Ortho-K. The paracentral corneal thickness showed no significant changes (p = 0.137), while the mid-peripheral corneal thickness was increased by 3.25 ± 1.6 μm associating this increase exclusively to the epithelial plot (p<0.001). When lens centration was assessed, a lens fitting decentration less than 1.0 mm was found for the whole sample, predominantly horizontal-temporal (87.5%) and vertical-inferior (50%) decentring. Corneal topographical analysis revealed a horizontal and vertical epithelial thickness asymmetric change profile with paracentral temporal thinnest values, and mid-peripheral nasal thickest values. ConclusionsThe present study found a central corneal thinning induced by Ortho-k lenses in subjects with moderate myopia, only associated with a change in epithelial thickness, as well as mid-peripheral thickening, that seems to be mainly epithelial in origin. The authors also found a tendency of contact lens decentration toward temporal and inferior areas conditioning an asymmetric epithelial redistribution pattern.