Corneal topography and computerized contact lens-fitting modules

Caroline, Patrick; Andre, Mark; Norman, Craig

doi:10.1016/0892-8967(94)90087-6

Cited by 18 publications

(11 citation statements)

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“…Knowledge of corneal topography provides a tool for early detection and diagnosis of keratoconus and similar corneal pathology (Smolek et al ., 1994; Maeda et al ., 1995); provides a method for defining the optical properties of the cornea's anterior surface (Klein and Mandell, 1995); a foundation on which to base a rationale for therapy and a sensitive means of evaluating therapy (Morrow and Stein, 1992; Antalis et al ., 1993; Applegate and Howland, 1995). In addition, the information can be used in contact lens practice to design a lens back surface geometry to provide an optimum fit (Douthwaite, 1991; Caroline et al ., 1994; Lester et al ., 1994; Maeda and Klyce, 1994). The VK studies have attempted to measure the precision and accuracy of the instruments (McCarey et al ., 1992; Wilson et al ., 1992; Douthwaite, 1995).…”

Section: Introductionmentioning

confidence: 99%

The asphericity, curvature and tilt of the human cornea measured using a videokeratoscope

Douthwaite

2003

Ophthalmic Physiologic Optic

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Section: Introductionmentioning

confidence: 99%

The asphericity, curvature and tilt of the human cornea measured using a videokeratoscope

Douthwaite

2003

Ophthalmic Physiologic Optic

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“…Following the standard procedure of keratometry, empirical fitting success with soft toric contact lenses can be anticipated in spherical corneas, central astigmatism, or corneas with peripheral toricity matched with central toricity. Considering that high and irregular peripheral corneal toricity occurs in the majority of astigmatic patients, including empirical soft contact lens fitting based upon more corneal topographical parameters, sagittal height, and corneal diameter, may lead to increased fitting success, better visual acuity, and fewer drop-outs [8][9][10]. Incorporation of all of these parameters requires customized soft contact lenses with varying base curves, diameters, sagittal heights, and power values [11,12].…”

Section: Introductionmentioning

confidence: 99%

Is the Use of Empirically Designed Custom Soft Contact Lenses a Good Option for Challenging Patients?

Spors¹,

Egan²,

McNaughton³

et al. 2013

OJOph

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Purpose: Reasons for the lack of success for contact lens patients range from poor fit, to discomfort or to a less than optimum wearing schedule. This project was a preliminary investigation of customized soft toric contact lenses as an alternative for unsuccessful contact lens patients or potential drop-outs. Methods: Fifteen healthy non-compromised, previously unsuccessful contact lens wearing patients (13 women, 2 men) with ages from 21 to 33 years (25.1 ± 2.7 years) were the subjects for this study. They were empirically fitted with 15 astigmatic and 5 spherical customized Spe-cialEyes soft contact lenses. Visual acuities, comfort, lens movement, and rotation were evaluated. Results: Patients fitted with customized SpecialEyes soft contact lenses had statistically significant better visual acuities than with Phoropter Manifest Refraction. The lenses used in this study centered well and moved no more than 1 mm upon each blink. Lens rotation was less than 10 degrees for all toric lenses. Patients gave very positive vision and comfort ratings. Conclusion: This preliminary study supports the application of a software program to empirically design and manufacture SpecialEyes custom soft lenses based upon corneal topographical parameters and subjective manifest refraction for those patients who either have challenging corneal parameters, high sphero-cylindrical prescriptions, or are currently dissatisfied with their contact lenses and are potential drop-outs.

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“…Rigid contact lenses fit within the cornea and therefore keratometry can be useful, although the added benefit of computerised video keratoscopy, especially in more complex situations such as orthokeratology or fitting a keratoconic eye, has been well documented [13,14]. Sclerals and semi-sclerals vault the cornea for central curvature is of little importance to corneal clearance based on the sagittal depth of the eye.…”

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confidence: 99%

Keratometry – A technique that should be relegated to the clinical dark ages?

Wolffsohn

2017

Contact Lens and Anterior Eye

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Keratometry -a technique that should be relegated to the clinical dark ages? Wolffsohn, James S W The selection of initial base curve has traditionally been based on central corneal curvature, as measured by keratometry. The underlying assumption behind this approach is that flatter corneas have less sagittal height and therefore require a lens of less sagittal depth in the form of a flatter base curve to optimally fit the cornea and vice versa [1]. Ocular sagittal height, though, is governed not just by central corneal curvature, but also by corneal diameter, corneal shape factor and the peripheral corneo-scleral profile [1,2]. This explains why changing from a 8.4 to a 8.7mm lens does not always solve a poor fitting issue in the same material [3], or why a 8.4 in one material/design may not perform the same as a 8.4 in a different product [4], due to different peripheral curves and edge lift amounts. It has been

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Corneal topography and computerized contact lens-fitting modules

Cited by 18 publications

References 0 publications

The asphericity, curvature and tilt of the human cornea measured using a videokeratoscope

The asphericity, curvature and tilt of the human cornea measured using a videokeratoscope

Is the Use of Empirically Designed Custom Soft Contact Lenses a Good Option for Challenging Patients?

Keratometry – A technique that should be relegated to the clinical dark ages?

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