共查询到20条相似文献，搜索用时 31 毫秒
1.
Clara Llorens-Quintana Maryam Mousavi Dorota Szczesna-Iskander D. Robert Iskander 《Contact lens & anterior eye》2018,41(1):18-22
Purpose
To evaluate the effect of two types of daily contact lenses (delefilcon A and omafilcon A) on the tear film and establish whether it is dependent on pre-corneal tear film characteristics using a new method to analyse high-speed videokeratoscopy recordings, as well as to determine the sensitivity of the method in differentiating between contact lens materials on eye.Methods
High-speed videokeratoscopy recordings were analysed using a custom made automated algorithm based on a fractal dimension approach that provides a set of parameters directly related to tear film stability. Fifty-four subjects participated in the study. Baseline measurements, in suppressed and natural blinking conditions, were taken before subjects were fitted with two different daily contact lenses and after four hours of contact lens wear.Results
The method for analysing the stability of the tear film provides alternative parameters to the non-invasive break up time to assess the quality of the pre-corneal and pre-lens tear film. Both contact lenses significantly decreased the quality of the tear film in suppressed and natural blinking conditions (p<0.001). The utilised method was able to distinguish between contact lens materials on eye in suppressed blinking conditions. The pre-corneal tear film characteristics were not correlated with the decrease in pre-lens tear film quality.Conclusion
High-speed videokeratoscopy equipped with an automated method to analyse the dynamics of the tear film is able to distinguish between contact lens materials in vivo. Incorporating the assessment of pre-lens tear film to the clinical practice could aid improving contact lens fitting and understand contact lens comfort. 相似文献2.
Varsha M. Rathi Preeji S. Mandathara Srikanth Dumpati Virender S. Sangwan 《Contact lens & anterior eye》2018,41(2):234-237
Background
To report the use of scleral lens (ScCL) to improve vision in patients having keratoconus who had intracorneal ring segment (ICRS) surgery.Methods
Two eyes of two keratoconus patients fitted with ScCL (PROSE ? prosthetic replacement of the ocular surface ecosystem, USA) after having undergone ICRS surgery are reported as noncomparative interventional case series. The ICRS implanted were INTACs and kerarings. Indications, visual acuity with ScCL, complications and follow-up are reported.Results
Case 1 underwent ScCL trial as he was referred for keratoplasty for being contact lens intolerant after ICRS surgery. Case 2 was intolerant to both corneal rigid gas permeable (RGP) lens and soft contact lens (SCL). 18.5 and 18 mm diameter ScCLs were dispensed to Case 1 and 2 respectively. The ScCLs had adequate corneal clearance with no corneal touch. There was no staining of the cornea or vascularization with the lens use. Case 1 complained of double images during trial with different Front surface eccentricity (FSE). A ScCL that did not cause diplopia was ordered. At four months of lens wear, the patient had diplopia with ScCL, which cleared when second lens with changed FSE was dispensed. Case 2 used SCL for five years before ScCL was fitted. He used the same ScCLs for five years. ScCL use resulted in improved comfort and visual acuity of 20/20. No complications were noted.Conclusions
ScCL may be tried in patients who have ICRS and are intolerant to corneal RGP or SCL and before subjecting such patients to keratoplasty. 相似文献3.
Patient-related barriers to Rigid Gas Permeable (RGP) lens wear among keratoconus patients in Jordan
Purpose
To assess potential patient-related barriers to rigid gas permeable (RGP) lens wear for vision rehabilitation in a sample of keratoconus (KC) patients in Jordan.Methods
Barriers for RGP contact lens wear among KC patients were discussed and specified by a focus group which consisted of five optometrists who are involved in contact lens practice. The focus group addressed potential barriers for RGP lens wear from the patient’s perspective. The identified barriers were then used to design the final questionnaire used in the study. The questionnaire consisted of 8 questions which ask the participant to rate, within a 5-points scale (1: strongly disagree to 5: strongly agree), how each suggested item is considered a barrier for RGP lens wear.Results
204 KC patients (86 females, 118 males) were involved in a semi-structured interview to answer the questionnaire. The average age of participants was 30.85 (±8.74) years old and ranged from 18 to 62 years. The average age of diagnosis of KC (± standard deviation) is 21.96 (±7.22) years old with a range of 12–52 years. All participants reported that they had never tried RGP lenses for their vision rehabilitation; however, other management options were reported such as glasses, keratoplasty, collagen cross linking and Intacs. The mean score of total barriers to RGP wear was high at 3.8 (±0.4) (out of 5). The major identified barriers were: lack of awareness of the benefits of RGP lenses, fear of possible lens complications, lack of medical insurance and high cost of the lens.Conclusions
The study reveals that several barriers were identified as prevalent. Consequently, there is an imperative need to adopt better planning strategies for management protocol of KC in order to assure best eye care service for KC patients in Jordan. 相似文献4.
Motohiro Itoi Motozumi Itoi Nathan Efron Philip Morgan Craig Woods 《Contact lens & anterior eye》2018,41(4):369-376
Purpose
To review contact lens prescribing trends in Japan between 2003 and 2016.Methods
An annual survey of contact lens prescribing trends was conducted each year between 2003 and 2016. Japanese ophthalmologists were asked to provide information relating to ten consecutive contact lens fittings between January and March every year.Results
Over the 14 years of the annual survey, data from a total of 64,122 contact lens fits were returned by ophthalmologists. The mean age (±SD) of lens wearers was 30?±?13?years, and 68% were female. The proportion of rigid lens fits decreased over time, from 35.4% in 2003 to 14.7% in 2016. Across this period, daily disposable lens fits increased, representing 46% in 2016. The proportion of toric lenses and multifocal lenses gradually increased, from 6.6% and 1.9% to 12.3% and 5.8%, respectively. Silicone hydrogel material use grew from 0% to 43.2%, while mid and low water content lens materials declined from 54.1% and 28.2% to 36.1% and 8.3%, respectively. Multi-purpose lens care solutions dominated the market over the 14?year survey period.Conclusions
This survey has revealed prescribing trends and preferences in Japan over the past 14 years, with the main changes observed being a decrease in rigid lens use and an increase in the use of silicone hydrogel materials and daily disposable lenses. 相似文献5.
Purpose
To evaluate the tolerability of and subject and investigator satisfaction with delefilcon A (DAILIES TOTAL1®) daily disposable contact lenses in first-time contact lens wearers.Methods
This European multicenter, open-label, single-arm, two-week trial enrolled first-time contact lens wearers and fitted them with delefilcon A contact lenses. Assessments were made at dispensing and at Weeks 1 and 2. Subject-reported outcomes included comfort, quality of vision, convenience, and intent to purchase, which were ranked by agreement responses. Investigator-reported outcomes included slit-lamp biomicroscopy findings and lens fit satisfaction.Results
Ninety-two subjects were included in the per protocol dataset. Mean scores at Weeks 1 and 2 for subject-reported quality of vision and ocular comfort were significantly higher with delefilcon A contact lenses than with the subjects’ habitual spectacles during the day, at the end of the day, and overall (all p?≤?0.02). Ninety-one percent of subjects reported that their study lenses were more comfortable than expected, 98% agreed that they were convenient to use, and 92% were interested in purchasing the lenses (all p?<?0.001). Investigators reported that study lenses had an acceptable fit in at least 97% of subjects.Conclusions
Practitioners can expect favorable outcomes when transitioning first-time contact lens wearers from spectacles to delefilcon A daily disposable contact lenses. 相似文献6.
Negar Babaei Omali Lakshman N. Subbaraman Miriam Heynen Alan Ng Chantal Coles-Brennan Zohra Fadli Lyndon Jones 《Contact lens & anterior eye》2018,41(4):329-334
Purpose
To determine and compare the levels of surface versus bulk active lysozyme deposited on several commercially available hydrogel contact lens materials.Methods
Hydrogel contact lens materials [polymacon, omafilcon A, nelfilcon A, nesofilcon A, ocufilcon and etafilcon A with polyvinylpyrrolidone (PVP)] were incubated in an artificial tear solution for 16?h. Total activity was determined using a standard turbidity assay. The surface activity of the deposited lysozyme was determined using a modified turbidity assay. The amount of active lysozyme present within the bulk of the lens material was calculated by determining the difference between the total and surface active lysozyme.Results
The etafilcon A materials showed the highest amount of total lysozyme activity (519?±?8?μg/lens, average of Moist and Define), followed by the ocufilcon material (200?±?5?μg/lens) and these two were significantly different from each other (p?<?0.05). The amount of surface active lysozyme on etafilcon and ocufilcon lens materials was significantly higher than that found on all other lenses (p?<?0.05). There was no active lysozyme quantified in the bulk of the nelfilcon material, as all of the active lysozyme was found on the surface (1.7?±?0.3?μg/lens). In contrast, no active lysozyme was quantified on the surface of polymacon, with all of the active lysozyme found in the bulk of the lens material (0.6?±?0.6?μg/lens).Conclusions
The surface and bulk activity of lysozyme deposited on contact lenses is material dependent. Lysozyme deposited on ionic, high water content lens materials such as etafilcon A show significantly higher surface and bulk activity than many other hydrogel lens materials. 相似文献7.
Jaya Sowjanya Siddireddy Ajay Kumar Vijay Jacqueline Tan Mark Willcox 《Contact lens & anterior eye》2018,41(2):144-153
Purpose
To investigate characteristics of the eyelid margins, meibomian glands and the tear film of contact lens wearers, and to determine whether these characteristics were related to symptoms of contact lens discomfort.Methods
A cross sectional study was performed on thirty existing daily wear soft contact lens wearers (6 male; 24 female) with median age of 23 years (range 18–41). Eyelid signs and tear film characteristics were evaluated during a single visit and subjects completed the contact lens and dry eye questionnaire (CLDEQ-8) to evaluate ocular discomfort.Results
Based on the CLDEQ-8 responses, subjects were classified as symptomatic (n?=?17) or asymptomatic (n?=?13). Grades of foam at meibomian gland orifices (3?±?1), expressibility (2?±?1) and quality of secretions (2?±?1), tear evaporation rate with (112?±?54?g/m2/h) or without (88?±?45?g/m2/h) contact lens wear, fluorescein tear breakup time (8?±?2 seconds) and tear lipid layer thickness (45?±?17?nm) were significantly associated with symptoms of discomfort in symptomatic lens wearers only (r2?>?0.45; p value?<?0.05). Upper lid-wiper epitheliopathy, meibomian gland acini reflectivity and tear meniscus height showed significant correlations with comfort scores in both symptomatic and asymptomatic contact lens wearers (p?<?0.05). A greater number of Demodex mites was also observed in the upper eyelid of symptomatic lens wearers (2?±?1) compared to asymptomatic lens wearers (0?±?0; p value?=?0.042).Conclusions
Morphological irregularities of the meibomian glands and alterations to tear film secretions that affect tear evaporative dynamics were associated with symptoms of discomfort amongst the symptomatic lens wearers. 相似文献8.
Emilia Novillo-Díaz César Villa-Collar Mónica Narváez-Peña José Luis R. Martín 《Contact lens & anterior eye》2018,41(3):258-262
Purpose
To determine if the discontinuation of commercially-available simultaneous vision Multifocal Soft Contact Lenses is independent from the multifocal design. To determine causes for discontinuation and psychosocial factors involved.Methods
Multicentre single-blinded randomised controlled trial with external blinded evaluation for a three months follow-up period for three intervention groups. 150 single-vision soft wearers were randomly assigned a spherical near centred lens (S-CN), distance centred lens (CD) or aspherical near centred lens (A-CN). Cases of discontinuation, anxiety and quality of life were measured at one week and one month.Results
120 females and 30 males were included with an age range of 40–62 (48.79?±?5.23). At one month, the S-CN design had a statistically significant higher risk of discontinuation than the other two OR: 6.12 (95%CI 2.5–14.9). Twenty-eight subjects discontinued wearing S-CN at first week (56%), while discontinuation of CD and A-CD were 15 (30%) and 11 (22%), with a statistically significant difference between S-CN design and the other two (p?=?0.001). There were not statistically significant differences when direct comparison between discontinuation of CD and A-CN was made (p?=?0.36). Thirty-two percent discontinued the use because of poor distance vision and 28% because of both poor distance and near vision. Psychosocial factors were not statistically significant.Conclusions
Discontinuation of Multifocal Soft Contact Lenses is dependent on the design. Most common cause for discontinuation is poor distance vision. Psychosocial factors do not impact on discontinuation rates. 相似文献9.
Samuel Abokyi George Manuh Heinz Otchere Alex Ilechie 《Contact lens & anterior eye》2017,40(5):329-334
Background
Despite findings that contact lens wear for vision correction provides better quality of life than spectacles, contact lens use in developing countries is low. This study evaluated knowledge, usage and barriers associated with contact lens wear among spectacle wearers in Cape Coast, Ghana.Method
A cross-sectional survey using a structured questionnaire was conducted on an adult population of spectacle wearers to assess their knowledge of contact lens wear for vision correction. The participants were proportionately sampled from three eye clinics in the Cape Coast Metropolis, Ghana. Questionnaires were either self-administered or completed with the help of a research assistant.Results
Of the 422 participants, only 147 (34.8%) knew of contact lens wear for vision correction. The proportion of spectacle wearers reporting history of contact lens wear was 14 (3.3%). Barriers to contact lens wear reported were satisfaction with vision through spectacles 102 (25.0%), lack of adequate information 111 (27.2%), fear of side effects 94 (23.0%) and cost 78 (19.1%). The younger adults and those with higher number of changes of spectacles were more likely to know of contact lenses.Conclusion
Knowledge and usage of contact lenses among spectacle wearers was low. Contact lens education and demonstration of visual performance through fitting of trial contact lenses on potential candidates may help overcome barriers to contact lens wear. 相似文献10.
Daniel Wong Julie M. Albietz Huan Tran Cimonette Du Toit Anita Hui Li Tina Yun Jee Han Katrina L. Schmid 《Contact lens & anterior eye》2017,40(6):389-393
Aim
Contact lens induced dry eye affects approximately 50% of contact lens wearers. The aim was to assess the effects of Manuka (Leptospermum sp.) honey eye drops (Optimel, Melcare, Australia) on dry eye in contact lens wearers. The safety of the honey eye drops in contact lens wear and contact lens wearers’ compliance were also evaluated.Design
Prospective, randomised, cross over study, examiner masked, pilot treatment trial.Methods
Twenty-four participants aged 20 to 55 years with contact lens related dry eye were recruited and randomised to two treatment groups; 20 completed the study. One group used Optimel eye drops twice a day for two weeks followed by conventional lubricant (Systane Ultra, Alcon) therapy for two weeks; the other group completed the treatments in the reverse order. Before and after each treatment dry eye symptomology, ocular surface inflammation, and tear quantity and quality were assessed. Participants completed a daily log detailing their usage of treatments and any issues.Results
Dry eye symptoms improved significantly after Optimel treatment. Patients with more severe symptoms at baseline showed a greater improvement in symptoms. No significant differences were observed in the objective signs of dry eye; presumably because of the short treatment duration. Seventy-five% of contact lens wearers reported good adherence to Optimel treatment and 95% reported no issues using this product.Conclusions
Optimel Eye Drops reduce the symptoms of dry eye in contact lens wearers and are safe to use. A longer treatment period to assess the effect on clinical signs of dry eye is required. 相似文献11.
António Queirós César Villa-Collar Ana Amorim-de-Sousa Beatriz Gargallo-Martinez Ramón Gutiérrez-Ortega Javier González-Pérez José M González-Méijome 《Contact lens & anterior eye》2018,41(6):507-512
A statement of Significance
For the first time, this study shows that corneas that previous undergone orthokeratology treatment do not respond differently to LASIK compared with previous soft contact lens wear experience.Purpose
To evaluate and compare the corneal morphology and visual outcomes of long-term soft and orthokeratology (OK) contact lens fitting in wearers undergoing corneal refractive surgery (LASIK) for myopia correction.Methods
Sixteen (16) myopic patients wearing hydrophilic soft contact lens (SCL, n?=?8 subjects, control group) and OK (n?=?8 subjects, OK group) lenses who undergone LASIK were retrospectively evaluated. Preoperative fitting of contact lenses and one year postoperative were studied using Pentacam (Oculus, Inc. GmbH, Wetzlar, Germany). Corneal pachymetry and volume, corneal topography, anterior and posterior surface elevation data and the anterior surface aberrometry of the cornea were recorded and used for fitting.Results
Age, refractive error and topographic parameters before LASIK did not showed statistically significant differences between the two study groups. LASIK post-treatment results showed identical changes in both control and OK groups and did not show significant differences in all the parameters evaluated. The changes on corneal parameters and HOA due to refractive surgery intervention were not different between Control and OK group (p?>?0.050).Conclusions
Corneal changes due to OK treatment are reversible after its discontinuation. The present study gives an overview of how OK does not impair future LASIK surgery for the correction of myopia and does not influence the success/results of such intervention. These findings suggest that OK CL wear does not change corneal biomechanics and does not compromise a possible LASIK refractive surgery. Although this is a pilot study and there is a need of evaluate this results/changes in future studies. 相似文献12.
Zhi Chen Jiaqi Zhou Xiaomei Qu Xingtao Zhou Feng Xue 《Contact lens & anterior eye》2018,41(3):263-266
Purpose
To investigate the effect of orthokeratology (ortho-k) lens wear on axial length (AL) growth in juvenile myopic anisometropes.Methods
This retrospective study consisted of two parts. In Part One, 25 anisometropic participants (mean age, 11.2?±?1.9?years; 11 females and 14 males) were fitted with ortho-k lenses in the more myopic eye only, and the rate of AL growth was compared between the ortho-k lens wearing eye and the untreated contralateral eye over an average period of 23.1?±?8.3?months. In Part Two, 8 participants who developed myopia in the contralateral eye received ortho-k treatment in both eyes for an average of 12 months; the rate of AL growth before and after ortho-k treatment in the newly developed myopic eye was compared.Results
In Part One, the rate of AL elongation in the ortho-k treated eye (0.08?±?0.15?mm/year) was significantly slower than in the contralateral eye (0.39?±?0.32?mm/year) (P?<?0.001). At the completion of Part One, 16 out of 25 participants (64%) developed myopia in the initially non-myopic eye. In Part Two, the rate of AL elongation after ortho-k treatment in the newly developed myopic eye (0.20?mm/year) was significantly slower than that before ortho-k treatment in the same eye (0.49?mm/year) (P?=?0.012).Conclusion
Ortho-k treatment slows AL growth in the more myopic eye of anisometropic patients; should the contralateral eye develop myopia in the future, ortho-k is capable of slowing down AL growth in that eye as well. 相似文献13.
14.
Purpose
This review summarises the way in which mechanical property measurements combined with clinical perception have influenced the last half century of materials evolution in contact lens development.Methods
Literature concerning the use of in-vitro testing in assessment of the mechanical behaviour of contact lenses, and the mutual deformation of the lens material and ocular tissue was examined. Tensile measurements of historic and available hydrogel lenses have been collected, in addition to manufacturer-generated figures for the moduli of commercial silicone hydrogel lenses.Results
The three conventional modes of mechanical property testing; compression, tension and shear each represent different perspective in understanding the mutual interaction of the cornea and the contact lens. Tensile testing provides a measure of modulus, together with tensile strength and elongation to break, which all relate to handling and durability. Studies under compression also measure modulus and in particular indicate elastic response to eyelid load. Studies under shear conditions enable dynamic mechanical behaviour of the material to be assessed and the elastic and viscous components of modulus to be determined. These different methods of measurement have contributed to the interpretation of lens behaviour in the ocular environment. An amalgamated frequency distribution of tensile moduli for historic and currently available contact lens materials reveals the modal range to be 0.3–0.6 MPa.Conclusion
Mechanical property measurements of lens materials have enabled calibration of an important aspect of their ocular interaction. This together with clinical feedback has influenced development of new lens materials and assisted clinical rationalisation of in-eye behaviour of different lenses. 相似文献15.
Purpose
To evaluate and compare changes in axial elongation, over a 14-month period, in subjects who discontinued and then resumed ortho-k lens wear with those who continued to wear their lenses or spectacles following a 2-year myopia control study.Method
This single masked, prospective study recruited subjects who had just completed a 2-year myopia control study. Ortho-k subjects were classified as Group OKc, in which subjects continued ortho-k lens wear for the duration of the study; or Group OKd in which subjects discontinued lens wear for seven months and wore single-vision spectacles (Phase I) and then resumed ortho-k lens wear for another seven months (Phase II). Spectacle-wearing control subjects from the initial myopia control study continued wearing spectacles as control subjects. Axial lengths were measured at scheduled visits using the IOLMaster.Results
Thirteen, 16, and 15 Control, OKc, and OKd subjects, aged 8–14 years, respectively completed the study. Significant increase in axial elongation was found in OKd subjects only in Phase I but not in Phase II. On resuming lens wear, in Phase II, the rate of axial elongation was no longer significantly different from those of the Control or OKc subjects.Conclusion
Stopping ortho-k lens wear at or before the age of 14 years led to a more rapid increase in axial length; comparable to those wearing spectacles during the initial 2-year myopia control study, but greater than the Control and OKc group in this study. Axial elongation slowed again with resumed lens wear after six months. 相似文献16.
Antonio J. Del Águila-Carrasco Daniel Monsálvez-Romín Eleni Papadatou 《Contact lens & anterior eye》2017,40(5):346-350
Purpose
To present a methodology for evaluating the optical quality of rotationally symmetrical contact lenses (CLs) from a single power profile.Methods
Simulated rotationally symmetrical power profiles corresponding to different CLs designs (monofocal, two-zone center-near bifocal, and four-zone center-distance bifocal) were used to calculate the wavefront error profile by means of numerical integration. Then, each lens wavefront error profile was spun around the center to obtain the lens wavefront error surface. From the surface, monochromatic optical transfer functions (OTF), simulated images and the visual Strehl ratio based on the OTF (VSOTF) were obtained for different distances and pupil sizes (3 and 5.5 mm) after performing a through-focus.Results
VSOTF variations, taking into account both vergence and pupil size, were presented for the three CLs designs. The monofocal design showed excellent optical quality only for far vision, whereas the bifocal designs exhibited good optical quality for far and near vision. Modulation transfer function (MTF) from each lens design, pupil size, and work distance agreed with the previous results.Conclusions
The methodology presented here allows for a rapid and thorough assessment of the optical quality of rotationally symmetrical CLs by means of optical quality metrics, with a special interest in simultaneous image contact lenses. This methodology may be useful for choosing the most suitable lens for each subject’s visual demands. 相似文献17.
Daddi Fadel 《Contact lens & anterior eye》2018,41(4):321-328
Purpose
To summarize the research findings on the ocular surface profile, to provide a definition and a classification of the corneoscleral shape, and to offer guidelines in selecting scleral lens design.Methods
The definition of rotational symmetry and rotational asymmetry was inquired and PubMed searches were conducted.Results
The better understanding of the scleral contact lens comportment on the eye and the introduction of new diagnostic instruments to measure the anterior ocular surface have led to improve comprehension of corneoscleral contour formulating new scleral lens designs. The scleral lens landing zone is influenced by corneoscleral profile which may be rotationally symmetric and rotationally asymmetric. Corneal sagittal height, limbal shape, corneoscleral junction profile, corneal, limbal, and conjunctival angles, and scleral shape should be taken in consideration to prevent and manage fitting problems, such as air bubble formation, midday fogging, localized blanching, impingement, conjunctival prolapse, lens decentration, lens flexure, and to increase comfort, wearing time, overall satisfaction, and visual quality.Conclusion
Corneoscleral shape may be considered rotationally symmetric including spherical, aspherical and toric profiles, and rotationally asymmetric including regular and irregular quadrants profiles. Each ocular surface contour requires a different landing zone design for an optimal fitting, vaulting properly over the cornea and limbus, and ideal alignment on the sclera. Further studies are still necessary to clarify many aspects of scleral lenses which are little known yet. 相似文献18.
Michael J. Doughty 《Contact lens & anterior eye》2017,40(2):109-115
Purpose
To assess if polymegethism and pleomorphism were evident in corneal endothelium after medium-term rigid gas permeable (RGP) contact lens wear.Methods
In a cross-sectional observational study over 12 years, single images of the central region of the corneal endothelium of one eye of 46 subjects were taken with a non-contact specular microscope, along with a measure of central corneal thickness (CCT). The images were printed onto A3-sized paper and 100 cells/image measured by planimetry.Results
Subjects aged between 20 and 32 years, with an average cumulative RGP wear of 6.0 +/? 1.6 years (range 3–9 years) were assessed; 26 of the subjects were Caucasian and 20 were Asian. The mean CCT was 0.515 +/? 0.027 mm. The group cell area value was 401 +/? 42 sq micron to give an estimated endothelial cell density (ECD) of 2520 +/? 273 cells/sq mm. As compared to a historical database, most endothelia (37/46) showed some changes with the mean coefficient of variation on cell area (COV) being 36.7 +/? 8.0% and the percentage of 6-sided (HEX) being 51.8 +/? 8.8%. There were modest correlations between years of RGP wear and both COV (p = 0.009, r spearman = 0.424) and HEX (p = 0.025, r spearman = ?0.291), but not for ECD or CCT.Conclusions
Corneal endothelial polymegethism appears to be a commonplace consequence of RGP lens wear with the magnitude of the change being related to the cumulative duration of the lens wear. 相似文献19.
Arianna Marelli Ivan Roberto De Vita Federica Cozza Silvia Tavazzi 《Contact lens & anterior eye》2018,41(6):531-537
Purpose
The aim was to evaluate the effects on corneal thickness (t) measurement, of asymmetry of the CCD position for a digital biomicroscope in specular reflection.Methods
t was deduced from the distance between reflexes from anterior and posterior corneal surfaces using a biomicroscope (Takagi SM70?N), with the illuminator either, (a) farther from sensor side (150 eyes) or, (b) closer to it (134 eyes). The distance between reflexes was also measured on a glass slide and a reference lens, with nominal thicknesses of 1580 and 520?μm, respectively. Corneal thickness (tPACH) was also measured by pachymeter (Canon TX-20?P).Results
When biomicroscope asymmetry was ignored, t for the glass slide was (a) 1760 and (b) 1404?μm. Correcting for the asymmetry provided corresponding values of 1588 and 1591?μm. For the lens, t was (a) 696 and (b) 543?μm, or 642 and 497?μm, when using the approximation of parallel surfaces (APS). Correcting for the asymmetry gave 565 and 552?μm (578 and 564?μm, with APS). Mean corneal t was (a) 560 and (b) 467?μm, (564 and 468?μm, with APS). Correcting for asymmetry gave (a) 506 and (b) 529?μm (508 and 530?μm, with APS). Mean tPACH was 552?μm.Conclusion
Biomicroscope asymmetry critically affects corneal thickness measurement in specular reflection. Induced errors can be accounted for and corrected, however. While the correction to the curvature radius is clinically relevant, it plays a minor role compared to asymmetry. 相似文献20.
Juan Carlos Montalt Esteban Porcar Enrique España-Gregori Cristina Peris-Martínez 《Contact lens & anterior eye》2018,41(4):351-356