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1.
Aim
Perception of reduced incidence of graft rejection after deep anterior lamellar keratoplasty (DALK) has attracted many surgeons towards this technique in keratoconus. This review aims to compare the visual, refractive and graft outcomes after penetrating keratoplasty (PK) and DALK for keratoconus.Methods
Electronic searches of PubMed, MEDLINE, EMBASE, Latin American and Caribbean Health Sciences Literature database (LILACS), metaRegister of Controlled Trials (mRCT), ClinicalTrial.gov and the WHO International Clinical Trials Registry Platform (ICTRP) were performed. We included randomized control trials (RCTs) and comparative studies to assess primary and secondary outcomes after PK and DALK in eyes with keratoconus. Primary outcome was best-corrected visual acuity (BCVA) LogMAR at ≥6 months. Secondary outcomes included number of patients with BCVA ≥ 0 LogMAR, uncorrected visual acuity (UCVA) LogMAR, spherical equivalent (SE), refractive and keratometric astigmatism, endothelial cell density (ECD) cell/mm2, graft rejection and graft survival.Results
Eighteen studies (including 2 RCTs) compared DALK (965 eyes) and PK (2402 eyes) for keratoconus. There was strong evidence through RCTs suggesting better LogMAR BCVA at ≥6 months and better LogMAR UCVA with PK; reduced refractive astigmatism and rejection with DALK and no difference in SE and keratometric astigmatism. Moreover, there was weak evidence to suggest better BCVA ≥ 0 LogMAR after PK and no difference in ECD between the two techniques.Conclusions
Despite the popularity of DALK amongst corneal surgeons for keratoconus, there is a paucity of high quality RCTs. The existing limited evidence confirms reduced rejection and refractive astigmatism with DALK but better visual outcomes with PK. Internationally agreed data sets and follow-up protocol are warranted. 相似文献2.
Corneo-scleral contact lenses in an uncommon case of keratoconus with high hyperopia and astigmatism
Esteban Porcar Juan Carlos Montalt Enrique España-Gregori Cristina Peris-Martínez 《Contact lens & anterior eye》2017,40(5):351-356
Purpose
To analyse the visual quality achieved by fitting corneo-scleral contact lenses (CScL) in an uncommon case of bilateral keratoconus, high hyperopia and astigmatism.Methods
A 45-year-old man presented for eye examination due to the unsatisfactory quality of his vision wearing soft toric contact lenses. He presented high hyperopia and astigmatism with bilateral keratoconus. He was fitted with CScL to correct his irregular astigmatism and ocular aberrations. A diagnostic trial set was used in the fitting process and he was assessed according to standardised fitting methodology. Visual acuity, corneal topography, biometry and ocular aberrations were evaluated. The follow-up period was 1 year.Results
The best spectacle-corrected visual acuity was 20/32 with +8.00/?4.50 × 30° for the right eye (RE) and 20/25 with +7.75/?2.25 × 120° for the left eye (LE). After CScL fitting, visual acuity was improved to 20/20 and 20/16 for the RE and LE, respectively. The patient wore these contact lenses an average of 13 h a day. The total high order aberrations decreased by approximately 79% in the RE (2.37–0.50 μm) and 47% in the LE (1.04–0.55 μm) after CScL fitting. Visual quality and wearing time were maintained after 1 year wearing CScL. In addition, no adverse ocular effects were found during this period.Conclusion
The present case report describes how the patient had CScL fitted successfully for management of keratoconus with high hyperopia and astigmatism. They provided optimal visual quality, along with prolonged use times and no adverse effects to the cornea. 相似文献3.
Purpose
To compare the current optometric practices and attitudes in the management of keratoconus patients in the UK and Spain.Methods
An online survey (adapted to optometric practices) was distributed via a newsletter emailed by various professional organizations in the UK and Spain.Results
Four hundred and sixty-four practitioners (126 in the UK; 338 in Spain) who prescribed gas permeable GP contact lenses (CLs) more than once per month (54.8% of UK practitioners and 28.1% of practitioners in Spain; p < 0.01) responded to the questionnaire. A combination of multiple factors is considered necessary in the keratoconus detection (79.4% in the UK, 75% in Spain; p = 0.68), and the use of classification criteria is considered relevant (67.5% in the UK, 70.7% in Spain; p = 0.49). There is a high consensus on the consideration that GP CL fitting is more difficult in keratoconus (79.4% in the UK, 80.5% in Spain; p = 0.79) requiring more diagnostic lenses (3.2 ± 1.4 and 3.4 ± 1.2 in the UK and Spain, respectively; p = 0.72) than are necessary for healthy eyes. Using corneal topography is uncommon from both countries (38.1% in the UK, 59.8% in Spain; p < 0.01), with a similar ophthalmologist referral pattern (at initial diagnosis, 50% in both the UK and Spain; p = 1.00). Few cases of co-management with ophthalmologists were noted (no co-management reported by 60.3% in the UK and 72.8% in Spain, p = 0.01).Conclusion
This study provides initial observations and evidence regarding keratoconus management by optometrists in the UK and Spain and shows similarity in the professional practices and attitudes of practitioners in these two countries. 相似文献4.
Michael T.M. Wang Irene Cho Soo Hee Jung Jennifer P. Craig 《Contact lens & anterior eye》2017,40(4):236-241
Purpose
To compare the effects on tear film parameters and contamination in cosmetic eyeliner wearers, after single application of two lipid-based dry eye treatments: a lipid-containing lubricant eye drop and a phospholipid liposomal spray.Methods
Fifty participants were enrolled in a prospective, randomised, paired-eye, investigator-masked trial. Pencil eyeliner (Body Shop® Crayon Eye Definer) was applied to the upper eyelid periocular skin of both eyes, anterior to the lash line. Baseline tear film quality was assessed fifteen minutes after eyeliner application. A lubricant drop (Systane® Balance) was then applied to one eye (randomised), and liposomal spray (Tears Again®) to the contralateral eye. Tear film contamination, lipid layer grade, non-invasive tear film break-up time and tear evaporation rate were evaluated fifteen minutes post-treatment and compared to pre-treatment values.Results
Pre-treatment measurements did not differ between eyes assigned to lubricant drop and liposomal spray. Tear film contamination was observed in a greater proportion of eyes following both treatments (both p < 0.05), with no significant difference between treatments (p = 0.41). Both treatments improved lipid layer thickness (both p ≤ 0.01), but effected no significant change in non-invasive tear film break-up time or tear evaporation rate (all p > 0.05). Changes in tear film parameters did not differ between treatments (all p > 0.05).Conclusions
Both the lipid-containing lubricant eye drop and phospholipid liposomal spray result in clinically apparent tear film contamination in eyeliner cosmetic wearers. Although both treatments effected an increase in lipid layer thickness, neither displayed clinical efficacy in improving tear film stability. 相似文献5.
Aim
To analyze the demographics, risk factors, clinical and microbiological characteristics of cases of bilateral simultaneous infective keratitis.Methods
In this retrospective case series, patients with clinical evidence of bilateral simultaneous infective keratitis were identified from January 1, 2011 to August 31, 2016. Demographics, risk factors, clinical and microbiological characteristics, and treatment outcomes were analyzed.Results
Five patients (ten eyes) with bilateral simultaneous infective keratitis were identified. The mean age was 32.8 years (SD, ± 8.8; range, 24–44). All the patients were disposable soft contact lens wearers before presentation. The average size of the infiltrate was 4.76 mm2 (SD ± 9.0; range, 0.2–31.34). A total of 4 types of bacteria were isolated, with Pseudomonas aeruginosa being the most frequently isolated bacteria involving 5 eyes of four patients. Infection resolved with medical treatment in 9 eyes, 1 patient required therapeutic corneal transplantation for impending corneal perforation. The average time taken for infection to resolve was 6.7 days (SD ± 4.5; range, 2–16).Conclusions
In this case series, the most common risk factor of bilateral simultaneous microbial keratitis was use of soft disposable contact lens and the most commonly isolated bacteria was Pseudomonas aeruginosa. Bilateral simultaneous infective keratitis is uncommon and is a serious complication of contact lens use in immunocompetent adult patients. 相似文献6.
Antonio Martínez-Abad David P. Piñero Pedro Ruiz-Fortes Alberto Artola 《Contact lens & anterior eye》2017,40(2):88-96
Purpose
To evaluate the diagnostic ability of the vector parameters ocular residual astigmatism (ORA), topography disparity (TD) and topographic astigmatism CorT (anterior and total) for the detection of clinical and subclinical keratoconus, and to develop a detection model based on them.Methods
This study comprised a total of 61 keratoconus eyes (KC group), 19 eyes with subclinical keratoconus (SKC group) and 100 healthy eyes (control group). In all cases, a complete eye exam was performed including an analysis of the corneal structure with the Sirius system (Costruzione Strumenti Oftalmici, CSO). Likewise, the iASSORT software (ASSORT Pty) was used to calculate in all cases the vector parameters ORA, TD and CorT.Results
Significant differences among groups were found in ORA, TD and CorT (anterior and total) (p < 0.001). The diagnostic ability of ORA (cutoff 1.255 D, sensitivity/specificity 82%/92%) and TD (cutoff 1.035 D, sensitivity/specificity 78.5%/86%) for the detection of keratoconus was good, whereas anterior and total CorT showed a poorer diagnostic ability. ORA (cutoff 0.925 D, sensitivity/specificity 63.2%/77%) and TD (cutoff 0.710 D, sensitivity/specificity 74%/68%) showed an acceptable diagnostic ability for the detection of subclinical keratoconus, but anterior and total CorT did not. A detection model for subclinical keratoconus was obtained by logistic regression analysis involving TD, anterior corneal spherical aberration and posterior high order aberrations.Conclusions
The vector parameters ORA and TD are useful for the diagnosis of clinical and subclinical keratoconus. In this last condition, the combination of TD with corneal aberrometric data provides a consistent detection model. 相似文献7.
Michael T.M. Wang Kalaivarny Ganesalingam Chee Seang Loh Trisha Alberquerque Suhaila Al-Kanani Stuti L. Misra Jennifer P. Craig 《Contact lens & anterior eye》2017,40(1):53-58
Purpose
To assess the effects of two weeks of regular phospholipid liposomal spray application on lipid layer grade, tear film stability, subjective comfort, visual acuity, and lipid deposition in silicone hydrogel contact lens wearers.Methods
Thirty-one existing contact lens wearers were enrolled and fitted with two week planned replacement silicone hydrogel contact lenses (Acuvue® Oasys®) in a prospective, randomized, paired-eye, investigator-masked trial. A phospholipid liposomal spray (Tears Again®) was applied to one eye (randomized) four times daily for two weeks. LogMAR high contrast visual acuity (VA), low contrast glare acuity (LCGA), non-invasive tear film break-up time (NIBUT), and lipid layer grade (LLG) were measured at baseline and day 14, in both treated and control eyes. Subjective comfort relative to baseline, and spectrofluorophotometric assessment of contact lens surface lipid deposition were also assessed on day 14.Results
All measurements did not differ at baseline between treated and control eyes. Lipid layer thickness and tear film stability were increased on day 14 in treated eyes (all p < 0.05), but not in control eyes (all p > 0.05). A greater proportion of participants reported improved comfort in the treated eye relative to the control eye (p = 0.002). There were no significant differences in visual acuity or in contact lens surface lipid deposition, between treated and control eyes, on day 14 (all p > 0.05).Conclusion
The phospholipid liposomal spray increased tear film stability, lipid layer thickness and subjective comfort in silicone hydrogel contact lens wearers, without adversely affecting visual acuity or contact lens surface lipid deposition. 相似文献8.
Esteban Porcar Juan Carlos Montalt Enrique España-Gregori Cristina Peris-Martínez 《Contact lens & anterior eye》2017,40(3):190-194
Purpose
We describe a case of fitting a corneo-scleral contact lens with a multi-aspheric geometry design (MAGD CScL) on top of a daily silicone hydrogel lens (piggyback system) for keratoconus management.Methods
A 48-year-old man using soft toric contact lenses required an improvement in the unsatisfactory quality of his vision. He presented with bilateral asymmetric keratoconus with high myopia in the right eye (RE) and severe myopia in the left eye (LE). In addition, he had low vision in his LE because of a maculopathy. He was fitted with MAGD CScL to correct his irregular astigmatism. A diagnostic trial set was used in the fitting process and the patient was assessed according to a standardised fitting methodology. Visual acuity, corneal topography and contrast sensitivity were evaluated. The follow-up period was 1 year.Results
The best spectacle-corrected visual acuity was 0.5 logMAR for the RE with ?10 D/-5 D × 60° and 2 logMAR for the LE with ?20 D/-3 D × 105°. After fitting MAGD CScL, visual acuity improved significantly to 0.1 logMAR for the RE and 1.3 logMAR for the LE, as well as contrast sensitivity. The fitting parameters of the base curve, diameter, and power were 7.05 mm, 12.60 mm, ?18.50 D and 7.15 mm, 12.60 mm, ?19 D for the RE and LE, respectively. Optimal fitting characteristics were found in terms of lens position and lens movement. To increase the time of MAGD CScL wear, they piggybacked on daily silicone hydrogel lenses of low power (?0.5 D). The patient reported being comfortable with this piggyback system for approximately 15 h a day. After 1 year of using the piggyback system, visual quality and wearing time were maintained. In addition, no adverse ocular effects were found during this period.Conclusion
This case report shows that in this patient a MAGD CScL could be fitted successfully on a daily silicone hydrogel lens in a piggyback system for keratoconus management, providing good visual quality along with prolonged use times and without adverse effects on the cornea. 相似文献9.
Purpose
To evaluate early visual rehabilitation, post-operative pain, epithelial healing and haze after transepithelial photorefractive keratectomy (TransPRK) using the SmartPulseTechnology (SPT) of Schwind Amaris (Schwind eye-tech-solutions GmbH, Kleinostheim, Germany).Methods
This was a retrospective comparative evaluation of a cohort of myopic patients undergoing TransPRK with SPT (group 1), with one matched control group that underwent conventional TransPRK (group 2). All cases had a 6-month post-operative follow-up including visual acuity and slit-lamp examination. Subjective evaluation of pain was recorded post-operatively.Results
49 eyes of 25 patients in group 1 and 40 eyes of 20 patients in group 2 were enrolled. The patients’ visual rehabilitation was significantly faster in group 1, one day and one week post-operatively (P < 0.05). From one month onward there was no significant difference between the groups. The epithelial defect size was significantly smaller on post-operative days 1 and 2 for group 1 (P < 0.05 in both cases). The pain score was also significantly less in group 1 (P < 0.05). The haze level had no significant difference between the groups at any post-operative point (P > 0.05).Discussion
TransPRK using SPT provides promising results in the early post-operative period. Visual rehabilitation, re-epithelialization and pain were faster in the early post-operative period in group 1 in comparison with group 2. Haze formation was not significantly different between the two groups; however, it was consistently less in group 1. 相似文献10.
Sarah La Porta Weber Rossen Mihaylov Hazarbassanov Alex Nasaré José Álvaro Pereira Gomes Ana Luisa Hofling-Lima 《Contact lens & anterior eye》2017,40(3):151-156
Purpose
To evaluate conjunctival impression cytology and HLADR expression changes after wearing scleral contact lenses (ScCLs) for moderate to severe dry eye disease (DED).Design
Prospective interventional case series.Methods
Forty-one eyes from 25 patients with moderate to severe DED were evaluated for Esclera ScCL treatment. Best-corrected visual acuity (BCVA) and slit-lamp findings were assessed. Impression cytology specimens were obtained from DED patients at the baseline and after wearing ScCLs for 12 months. The impression cytology specimens were analyzed using morphological results score, and HLA-DR positive cells were detected and quantified. The values were compared to assess the IC changes after wearing ScCLs.Results
Forty-one eyes from 25 patients were fitted with ScCLs to manage DED. The underlying diseases were Stevens-Johnson syndrome (22 eyes), Sjogren’s syndrome (11 eyes), graft-versus-host disease (2 eyes), dry eye after keratomileusis (2 eyes) and undifferentiated ocular surface disease (4 eyes). The HE-PAS impression cytology score did not differ significantly before and after wearing ScCLs for 12 months in DED patients (p > 0.05). The percentage of eyes expressing the HLA-DR antigen in the temporal conjunctiva after wearing ScCL for 12 months significantly increased in patients with Sjogren’s syndrome (11.11% to 66.66%; p = 0.0498). In groups with Stevens Johnson syndrome and other ocular surface disorders, we did not observe statistically significant differences (p > 0.05).Conclusions
The ScCLs did not change the parameters used to evaluate inflammatory processes, which were measured using conjunctival impression cytology and HLA-DR expression, except in Sjogren syndrome, in which there was an unexpected increase in HLA expression. 相似文献11.
Purpose
To describe a new methodology for tear-film dynamics assessment by observing fluorescein decay rate over time and to understand the relationship between the newly defined tear fluorescein washout rate (TFWR) and other measures of the tear film behaviour.Methods
Forty subjects (24F/16M) aged (mean ± standard deviation) 31.8 ± 14.2 years volunteered for the study. It consisted of the review of medical history, McMonnies questionnaire (McMQ), slit lamp examination, and TFWR using a newly-developed fluorescein profilometry. The repeatability of TFWR measurements was assessed. TFWR estimates were contrasted against patient age, McMQ score, daytime, fluorescein tear film break-up time (FTBUT), tear meniscus height (TMH) and blink frequency.Results
Mean repeatability of the method was 28.13 ± 9.59%. The group mean TFWR was 39 ± 23% at 30-s mark after the beginning of measurements, ranging from 1.4% to 83%. This indicates that TFWR is highly subject-dependent. Statistically significant correlations were found between the percentage TFWR and McMQ score (r2 = 0.214, p = 0.001) as well as FTBUT (r2 = 0.136, p = 0.009). No statistically significant correlations were found between TFWR and age, daytime, TMH, and blink frequency.Conclusions
Fluorescein profilometry allows clinicians to follow dynamic changes in the tear film on the entire ocular surface and may be used for qualitative assessment of the tear film dynamics. 相似文献12.
Purpose
This study was designed to develop a novel technique called non-invasive keratograph dry-up time (NIK-DUT), which used an adapted corneal topographer, to analyse in-vitro contact lens surface dewetting and the effects of combinations of lenses and lens care solutions on dewetting.Methods
Variables were assessed to optimise sensitivity and reproducibility. To validate the method, in-vitro dewetting of silicone hydrogel contact lenses (balafilcon A, comfilcon A, lotrafilcon A, lotrafilcon B and senofilcon A) was tested. All lens types were soaked in OPTI-FREE® PureMoist® Multipurpose Disinfecting Solution (OFPM) and Sensitive Eyes® Saline Solution. The mean NIK-DUT, defined as drying of 25% of the placido ring measurement segments (NIK-DUT_S25), was calculated for each lens/lens solution combination and a visual map constructed representing the time and location of the dry-up event.Results
Optimal conditions for NIK-DUT measurement included mounting onto a glass stage with a surface geometry of r = 8.5 mm, e = 0, and measuring with high intensity red or white illumination. This method detected significant differences in contact lens dewetting with different lens soaking solutions. NIK-DUT_S25 for all lenses was longer when pre-soaked in OFPM versus saline. Visual analysis showed that dewetting of contact lenses was not uniform across surfaces and differed between test solutions.Conclusions
NIK-DUT is suitable for detecting differences in dewetting among various contact lenses and lens-care combinations. NIK-DUT can quantify the dewetting of large areas of lens surfaces with little subjective influence. Lens care solutions containing surface-active wetting agents were found to delay surface dewetting of silicone hydrogel lenses. 相似文献13.
Purpose
To assess the repeatability and reproducibility of Visante? OCT and Oculus Pentacam HR® in measuring central (CCT) and topographic corneal thickness (TCT) along the principle meridians in keratoconus (KC) corneae.Method
Twenty participants diagnosed with KC were recruited. There were two study visits. On the first study visit, two repeated corneal thickness measurements were obtained with each instrument. Measurements were repeated at least 48hrs later in the same order. TCT were recorded in the 90, 180, 45 and 135 meridians at 1mm intervals across 8mm chord.Results
Mean CCT for Visante? OCT was 484.97 ± 43.14 μm (range: 484.84–486.09) and Oculus Pentacam HR® was 478.86 ± 45.31 μm (range: 477.20–480.53). No significant difference in TCT between the two visits (p = 0.54) and measurements (p = 0.63) for Visante? OCT. For Oculus Pentacam HR®, no significant difference was found for each visit (p = 0.18) but differences existed in the measurements outside of the central region (p = 0.001). Tukey post-hoc analysis shows the differences (p ? 0.05) were found in the +1 and +4 (supero-temporal) locations in the 135 meridian. Significant differences were found comparing the two instruments, (p < 0.05). Bland Altman plots were used to demonstrate the differences between the two instruments and indicate their limits of agreement.Conclusion
Both instruments gave repeatable measurements as no significant differences were found in most locations in all meridians. Comparing the two instruments, they were not reproducible in all locations. 相似文献14.
Purpose
The aim of this work was to investigate the locus and extent of vitronectin (Vn) deposition on ex vivo contact lenses and to determine the influence of wear modality together with surface and bulk characteristics of the lens material.Methods
The quantity and location of Vn deposition on the surfaces of contact lens materials was investigated using a novel on-lens cell attachment assay technique.Results
Vn mapping showed that deposition resulted from lens-corneal interaction rather than solely from the tear film. Higher cell counts on the posterior surface of the lenses were determined in comparison to the anterior surface. Overall gross Vn deposition was greater for high water content-low modulus materials (117 ± 4 average cell count per field) than low water content-high modulus materials (88 ± 6 average cell count per field).Conclusions
The role of Vn in plasmin regulation and upregulation is widely recognised. The findings in this paper suggest that the locus of Vn on the contact lens surface, which is affected by material properties such as modulus, is potentially an important factor in the generation of plasmin in the posterior tear film. Consequently, the potential for materials to affect Vn deposition will influence lens-induced inflammatory processes. 相似文献15.
Aoife Lloyd-McKernan Luisa Simo Mannion Veronica O’Dwyer 《Contact lens & anterior eye》2017,40(5):301-310
Purpose
To examine the influence of previous soft contact lens (SCL) wear on corneal refractive surgery (CRS) outcomes when SCL wear is ceased for two weeks versus twenty-four hours, and also when compared to no wear, prior to CRS.Methods
A retrospective examination of CRS patient records was carried out for two groups of patients- who ceased SCL wear for two weeks (n = 45) and for twenty-four hours (n = 49) prior to CRS and compared to a non-contact lens (NCL) control group (n = 45 and n = 49, respectively). CRS outcomes (efficacy, predictability, visual acuity and refractive error) were compared pre-operatively and one and six months post-operatively.Results
One month post-operative results found unaided distance visual acuity (UDVA) was significantly better for LASEK/PRK patients who had ceased SCL wear for two weeks prior to CRS (?0.05 ± 0.09), compared with the NCL group (0.02 ± 0.09; p = 0.04). Furthermore, six month post-operative results found UDVA was significantly better for both LASIK and LASEK/PRK patients who had ceased SCL wear for two weeks prior to CRS, and for LASEK/PRK patients who had ceased SCL wear for twenty-four hours prior to CRS compared with the NCL group.Conclusions
Given the current setup and methods followed, it was concluded that previous SCL wear had no negative impact on visual outcomes following CRS compared with a NCL control group, regardless of previous SCL cessation time prior to CRS. 相似文献16.
Purpose
This study aims to evaluate the settling of a scleral lens and if this process is influenced by the nature of the fluid layer.Methods
A prospective, non-randomized control study was performed using an 18 mm scleral lens. They were fitted with a central clearance of 400 um at insertion. One eye was randomly assigned to be fitted with a non-preserved gel solution of carboxymethylcellulose, while the other was inserted with non-preserved saline. Measurements of clearance in 3 locations were taken (OCT) at baseline, every 30 min up to 1h30 post insertion and every 2 h thereafter up to 6h00 of wear. A two-way repeated measure analysis of variance (liquids × times) was used to test central, nasal and temporal fluid thickness.Results
Following 6 h of wear, the 18 mm lens had a mean central settling of 70.0 ± 9.8 μm, 36.7 ± 9.8 μm of which occurred within the first 30 min of wear. There was no significant difference between lenses filled with non-preserved saline to those with non-preserved gel. However, a paired comparison concluded to a significant difference between mean nasal settling (41.4 μm) and temporal settling (20.4 μm).Conclusion
With respect to the lens studied, current results suggest that practitioners can evaluate the lens 30 min post insertion and can estimate the amount of fluid that will remain after lens stabilization by doubling the value obtained initially. The use of non-preserved saline or non-preserved more viscous solution to fill the lens does not influence its settling. 相似文献17.
Purpose
To evaluate a novel fitting algorithm for estimation of alignment curve (AC) radius during orthokeratology lens trial.Methods
Fifty myopic children were recruited in this study. AC radii were estimated by both traditional method using flat K readings and eccentricity values and by a novel fitting algorithm, which was composed of 256 circle fittings using corneal elevation data from the corresponding AC region and a succedent toric fitting based on these calculated AC curvatures. Parameters of the final ordered lenses were determined by fluorescein analysis and corneal topography. The number of lens trials was recorded for each patient, and the consistencies of AC radius and astigmatism between the first trial lenses and the final ordered lenses were tested by Pearson correlations and Bland-Altman plots.Results
The numbers of trials for the novel algorithm and traditional method were 1.2 ± 0.4 times vs. 1.8 ± 0.7 times, respectively, and Mann-Whitney test showed significant difference (z = ?3.27, p = 0.001). AC radii of the first trial lenses estimated by the novel fitting algorithm were more close to that of the final ordered lenses, showing a R square value of 0.994 for the fitting algorithm and 0.927 for the traditional method, respectively. Similar results could also be noticed for astigmatism estimation.Conclusion
AC radius and astigmatism of ortho-k lens could be better estimated by two steps of fitting algorithm using corneal elevation data, which may shorten the time needed for ortho-k lens trial and achieve better lens fitting status. 相似文献18.
Sara Ortiz-Toquero Guadalupe Rodriguez Victoria de Juan Raul Martin 《Contact lens & anterior eye》2017,40(3):143-150
Purpose
To calculate and validate a new web-based algorithm for selecting the back optic zone radius (BOZR) of spherical gas permeable (GP) lens in keratoconus eyes.Methods
A retrospective calculation (n = 35; multiple regression analysis) and a posterior prospective validation (new sample of 50 keratoconus eyes) of a new algorithm to select the BOZR of spherical KAKC design GP lenses (Conoptica) in keratoconus were conducted. BOZR calculated with the new algorithm, manufacturer guidelines and APEX software were compared with the BOZR that was finally prescribed. Number of diagnostic lenses, ordered lenses and visits to achieve optimal fitting were recorded and compared those obtained for a control group [50 healthy eyes fitted with spherical GP (BIAS design; Conoptica)].Results
The new algorithm highly correlated with the final BOZR fitted (r2 = 0.825, p < 0.001). BOZR of the first diagnostic lens using the new algorithm demonstrated lower difference with the final BOZR prescribed (-0.01 ± 0.12 mm, p = 0.65; 58% difference ≤ 0.05 mm) than with the manufacturer guidelines (+0.12 ± 0.22 mm, p < 0.001; 26% difference ≤ 0.05 mm) and APEX software (-0.14 ± 0.16 mm, p = 0.001; 34% difference ≤ 0.05 mm). Close numbers of diagnostic lens (1.6 ± 0.8, 1.3 ± 0.5; p = 0.02), ordered lens (1.4 ± 0.6, 1.1 ± 0.3; P < 0.001), and visits (3.4 ± 0.7, 3.2 ± 0.4; p = 0.08) were required to fit keratoconus and healthy eyes, respectively.Conclusion
This new algorithm (free access at www.calculens.com) improves spherical KAKC GP fitting in keratoconus and can reduce the practitioner and patient chair time to achieve a final acceptable fit in keratoconus. This algorithm reduces differences between keratoconus GP fitting (KAKC design) and standard GP (BIAS design) lenses fitting in healthy eyes. 相似文献19.
Purpose
To report a case of lens discontinuation in a long term orthokeratology (OK) lens wearer and describe regression in refraction, corneal topography, and corneal thickness over 408 days after lens discontinuation. Furthermore, the outcome of subsequent LASIK treatment is also reported.Case report
A 41 year old Caucasian female who had been previously wearing OK lenses for 13 years discontinued lens wear in the left eye to consider refractive surgery in that eye. The greatest changes in subjective and objective refractions, corneal topography and thickness occurred during the first 28 days after lens discontinuation. Subjective refraction did not reach baseline values, but corneal topography parameters returned to pre-OK values after 408 days of no lens wear. The patient then received successful refractive surgery treatment in that eye, achieving uncorrected visual acuity of 0.00 LogMAR units, and residual refractive error within ±0.50 D of emmetropia.Conclusion
The period of lens discontinuation required for long term OK lens wearers before refractive surgery is likely to vary between individuals and the patient described in this case report required a significant period of lens discontinuation of at least one year before being considered suitable for refractive surgery. 相似文献20.
Jennie Diec Thomas Naduvilath Daniel Tilia Eric B. Papas Percy Lazon de la Jara 《Contact lens & anterior eye》2017,40(6):367-381