Topical anaesthetic use prior to rigid gas permeable contact lens fitting

CLEAR - Evidence-based contact lens practice

Evidence-based contact lens -->practice involves finding, appraising and applying research findings as the basis for patient management decisions. These decisions should be informed by the strength of the research study designs that address the question, as well as by the experience of the practitioner and the preferences and environment of the patient. This reports reviews and summarises the published research evidence that is available to inform soft and rigid contact lens history and symptoms taking, anterior eye health examination (including the optimised use of ophthalmic dyes, grading scales, imaging techniques and lid eversion), considerations for contact lens selection (including the ocular surface measurements required to select the most appropriate lens parameter, lens modality and material selection), evaluation of lens fit, prescribing (teaching self-application and removal, adaptation, care regimen and cleaning instructions, as well as -->minimising risks of lens wear through encouraging compliance) and an aftercare routine.

An approach for simulating the fitting of rigid gas-permeable contact lenses using 3D printing technology

OBJECTIVE

To introduce a new approach to simulatethe fitting process of rigid gas-permeable (RGP) contact lenses using 3D printing technology.

METHODS

A hemispherical or parabolic 3D model was created using 3D Builder or Tinkercad software. The horizontal and vertical diameters and the hemispherical or ellipsoid height were adjusted to simulate different morphologies of the corneal anterior surface. After exporting the file in stereo lithography (STL) format, a solid model was printed using a 3D printer and was used to simulate RGP contact lens fitting.

RESULTS

Limited by the precision of the entry-level 3D printer which was used in this study, the print-outs of the corneal models were crude, but the models were tested for their ability to simulate common corneal morphologies with no corneal astigmatism and different axial corneal astigmatism. Compared with some built-in simulation programs for corneal topography, the solid models generated by 3D printing could well simulate the positioning of the lens under the influence of gravity and the eyelid, as well as lens eccentricity or the bubbles under lenses caused by an improper wearing method.

CONCLUSION

3D printing technology can be well applied in the simulation of RGP contact lens fitting, which may become a new teaching method in optometry.