RESUMO
Purpose: We propose and evaluate the modifications of a light sword lens (LSL) to obtain better performance for distance vision while maintaining good operation for near and intermediate vision. Methods: The modifications consisted of assigning angular or circular windows for distance vision while rescaling the LSL profile in the remaining area of the element. The objective performance of the redesigned LSLs was verified numerically by the Strehl ratio and experimentally using correlation coefficients and Michelson contrast. Subjective assessments were provided by monocular visual acuity (VA) and contrast sensitivity (CS) through-focus curves for six patients with paralyzed accommodation. The tested object vergence range was [-4.0, 0.0] diopters (D). All experiments were conducted in a custom-made monocular visual simulator. Results: Computational simulations and objective experiments confirmed the better performance of the modified LSL for the imaging of distant objects. The proposed angular and radial modulations resulted in flat VA and CS through-focus curves, indicating more uniform quality of vision with clearly improved distance vision. The VA provided by the modified LSL profiles showed a maximal improvement of 1.5 lines of acuity with respect to the VA provided by the conventional LSL at distance vision. Conclusions: Optimized LSLs provide better imaging of distant objects while maintaining a large depth of focus. This results in comparable and acceptable quality for distance, intermediate, and near vision. Therefore, the modified LSLs appear to be promising presbyopia correctors. Translational Relevance: The new design of LSL reveals an improved performance for all ranges of vision and becomes a promissory element for a real presbyopia correction in clinical applications.
Assuntos
Cristalino , Lentes Intraoculares , Presbiopia , Sensibilidades de Contraste , Humanos , Presbiopia/cirurgia , Acuidade VisualRESUMO
Purpose: We present the first physiological evaluation of the use of the light sword lens (LSL) for presbyopia compensation. The LSL is an axially asymmetric optical element designed for imaging with extended depth of focus. Methods: A monocular visual simulator setup is implemented to measure visual acuity (VA). Physiological presbyopia is "mimicked" in human subjects by paralysis of the ciliary muscle, using topical application of a muscarinic antagonist. The effect of a contact lens-configured LSL on the mimicked presbyopia visual system is evaluated by measuring VA as a function of target vergence. The ability of the LSL to compensate presbyopia for 2 photopic luminance values was also analyzed. Results: The average VA values for 11 subjects suggest that the LSL can compensate for presbyopia across a wide range of target vergences for which the LSL was designed (-3 to 0 D). However, the proposed corrector element causes a loss of distance VA. The mean logMAR VA in that target vergence range was 0.07. The VA curves also show that luminance does not affect the expected behavior of the LSL-corrected presbyopic eye. Conclusions: These results indicate that the LSL has significant potential as a visual aid for presbyopia.