Predicting initial base curve of the rigid contact lenses according to Javal keratometry findings in patients with keratoconus

Berjandy, Fereshte; Nabovati, Payam; Hashemi, Hassan; Yekta, Abbasali; Ostadimoghaddam, Hadi; Sardari, Sara; Khabazkhoob, Mehdi

doi:10.1016/j.clae.2020.05.009

Cited by 7 publications

(9 citation statements)

References 25 publications

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“…The current study was conducted on participants with healthy eyes who may not be motivated for long-term GP lens wear, which is different to patients who have had penetrating keratoplasty or radial keratotomy, or patients with keratoconus or high irregular astigmatism. [29,30] In addition, this study aimed to investigate initial adaption over the first 20 minutes of lens wear; perhaps longer observation may be necessary to understand the extended impact of plasma coating and lens diameter. Lastly, the participants were young health adults who may be more symptomatic to GP lens wear compared to an older population or individuals with underlying corneal conditions.…”

Section: Discussionmentioning

confidence: 99%

Effect of large diameter and plasma coating on the initial adaptation of gas permeable contact lens fitting for neophytes

Dutta

Wolffsohn

2021

Contact Lens and Anterior Eye

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To determine whether the adaption of neophytes to rigid gas permeable lenses (RGPs) could be accelerated by changing their diameter or surface lubricity.Methods: This was a 2 part prospective double-masked randomised bilateral wear study. An RGP lens (Roflufocon D material, 9.6mm diameter) with and without a Hydrapeg plasma coating surface was worn by 119 neophytes (21.1±3.5 years; 77% female) on separate occasions. A further 114 neophytes (average age 20.1±1.0 years; 72% female) wore the uncoated lens with a randomly allocated 9.6mm diameter lens one one eye and 10.1mm (n=51) or 10.6mm (n=63) in the other with a basecurve compensation keeping the fit the same. Lens fit and corneal staining was assessed after 20 minutes, and comfort and bulbar redness were assessed at the time of lens application and after

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Section: Discussionmentioning

confidence: 99%

Effect of large diameter and plasma coating on the initial adaptation of gas permeable contact lens fitting for neophytes

Dutta

Wolffsohn

2021

Contact Lens and Anterior Eye

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“…Although corneal topography plays a substantial role in monitoring of KCN and determining the parameters required to administer contact lenses, 4 5 one must consider the cost and application of routine instruments when prescribing lenses. 6 7 Hand-held keratometer is commonly used in contact lens clinics. They are less expensive and available to people living in more disadvantaged areas.…”

Section: Introductionmentioning

confidence: 99%

“…They are less expensive and available to people living in more disadvantaged areas. 7 8 Furthermore, it has been found that among five corneal topography devices including Pentacam, EyeSys, Orbscan, IOL Master, and Javal keratometer, the reproducibility and accuracy of Javal keratometer following Pentacam were greater than those of the other devices. 9 …”

Section: Introductionmentioning

confidence: 99%

“…One way to achieve this purpose is to take advantage of those models and formulas proposed by researchers and lens manufacturers. 7 Due to the important role of determining the accurate power of contact lens to enhance vision in KCN patients, the aim of this study was to find an appropriate regression model for predicting the initial power of corneal RGP contact lenses. This was done using routine measuring instruments and considering patients’ corneal power and refractive errors.…”

Section: Introductionmentioning

confidence: 99%

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Initial power of rigid gas permeable contact lenses in patients with keratoconus

et al. 2021

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Purpose: To simplify the fitting process, this study was designed to predict the initial power of contact lenses using the regression model based on manual Javal keratometry data and refractive errors. Methods: In this retrospective study, 121 eyes of 69 patients with keratoconus (KCN) were fitted with a specific trial set of rigid gas permeable contact lenses based on the standard criterion of “three-point touch” over a 7-year period. Power of the cornea was measured using Javal keratometer. Refractive errors and over refraction of patients were diagnosed using Topcon autorefractometer (RM-A2000) and confirmed by Heine beta 2000 retinoscope. Results: The results of multiple linear regression showed the following equation: power of contact lens = −14.368 (constant of the final multiple regression model), +0.475 (spherical refraction), and +0.275 (flatter corneal power). Conclusions: The results of this study revealed that lens power has a significant relationship with the power of the flat corneal meridian and spherical refractive error in KCN patients. The obtained regression model can be used to shorten patients’ chair time and optometric examination for predicting the power of contact lens.

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“…In order to select the contact lens to be tried in a KC patient and to monitor the effects of this lens on the anterior segment structures, anterior segment parameters should be reliably monitored in CXL-treated corneas. 6,7 With the advancing technologies in the last few decades, the cornea can be imaged with many different methods based on different studying principles. 8,9 Therefore, it is important to determine the optimal method for the measurement of corneal parameters, such as keratometry and central corneal thickness (CCT) to obtain more reliable values to be also used in the follow-up and grading of the disease.…”

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confidence: 99%

Reliability of Optical Devices in Terms of Measurements of Corneal Parameters in Cross Linked Keratoconic Eyes: Cross-Sectional Study

MUHAFİZ¹,

Bozkurt²,

NİZAMOĞULLARI³

2022

Turkiye Klinikleri J Ophthalmol

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To determine the reliability and agreement of different optical devices in terms of keratometry and pachymetry measurements in cross-linked (CXL) keratoconic eyes. Material and Methods: Thirty-eight CXL-treated keratoconic eyes were evaluated. Three repeated measurements were performed with Topcon KR-1 autorefractokeratometry, Sirius topography, Nidek AL-scan optical biometry and RTVue anterior segment optical coherence tomography (AS-OCT). The devices were compared in terms of pachymetry and keratometric values. Limits of agreement (LoA) between the devices were detected using Bland-Altman analysis. Intra-examiner reliability was obtained using the intraclass correlation coefficient (ICC). Results: While the mean central corneal thickness (CCT) and minimum corneal thickness (MCT) measured in AS-OCT were 456.37±41.52 μm and 431.89±43.37 μm, respectively, these values were 432.40±48.97 μm and 415.67±47.69 μm in topography (p<0.001). The 95% LoA between the devices were -21.7 to 69.7 μm for CCT and -17.7 to 50.1 μm for MCT. Intra-examiner reliability was excellent for both devices in relation to the CCT and MCT measurements (ICC>0.97). When devices were compared in terms of the keratometric values and corneal astigmatism measurements, there was a significant difference among devices except between autorefractokeratometry and optical biometry (p<0.05; for all). The lowest LoA among the devices was found to be 3.3 D for steep keratometry and 2.9 D for flat keratometry and 2.3 D for corneal astigmatism. Intra-examiner reliability was excellent in all three devices in terms of the keratometric measurements (ICC>0.99). Conclusion: Pachymetry and keratometry can be performed independently in each device with excellent reliability in CXL-treated keratoconic eyes. However, we consider that measurements made with different devices cannot be used interchangeably in these eyes.

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Predicting initial base curve of the rigid contact lenses according to Javal keratometry findings in patients with keratoconus

Cited by 7 publications

References 25 publications

Effect of large diameter and plasma coating on the initial adaptation of gas permeable contact lens fitting for neophytes

Effect of large diameter and plasma coating on the initial adaptation of gas permeable contact lens fitting for neophytes

Initial power of rigid gas permeable contact lenses in patients with keratoconus

Reliability of Optical Devices in Terms of Measurements of Corneal Parameters in Cross Linked Keratoconic Eyes: Cross-Sectional Study

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