Contact lens technology is advancing faster than ever before, and it is happening right before our eyes.

Myopia Control

One optical technology that is very much here and now is the use of specially designed contact lenses to slow the progression of myopia. Specialty soft and rigid lenses that apply the peripheral myopic defocus model, by corneal remodeling or concentric power rings, are being used to slow the progression of myopia (Wolffsohn et al, 2020; Jonas et al, 2021; Richdale et al, 2021; Vincent et al, 2021). New research is ongoing to examine the efficacy of combining contact lenses with pharmaceutical agents (Erdinest et al, 2021; Gao et al, 2021).

Higher-Order Aberrations

Traditional soft lenses or spectacles do not correct for the high-order aberrations (HOAs) seen in diseased corneas, such as in keratoconus (Jinabhai, 2020). Previously, rigid contact lenses were the only option to correct HOAs through the tear lens, neutralizing the cornea’s irregular shape. Currently, custom or aspheric soft lenses are being developed to correct HOAs (Marsack et al, 2013; Jinabhai, 2020).

Correcting HOAs is believed to improve vision quality; however, visual improvement differs significantly between patients since HOAs are influenced by blinking, tear film changes, varying pupil size, and lens decentration (Legras et al, 2004).

Accommodative Lenses

Optical strategies remain the backbone of management for presbyopia. The optimal accommodating contact lens should be able to give +2.00D of near power (Bailey et al, 2018). Two proposed mechanisms for an accommodating contact lens are mechanical and electronic or “tuned” mechanisms.

Mechanical lenses use the eyelids in lower gaze to flex the lens and cause the posterior lens tear film to change the dioptric power or use fluid flow within the lens to add the power (Win-Hall, 2011). An advantage that “tuned” lenses have is that they contain embedded microelectronics, allowing gaze tracking technology to control the focal point (Biederman et al, 2016). The change in optical power is achieved through shape changes by electroactive elements localized in the optic zone or embedded in the anterior or posterior segment of the lens that get pumped to the optic zone (Egan and Nibauer, 2016).

Another approach uses liquid crystals (similar to those in TV and computer screens) combined with low voltage to alter the lens’s refractive index (Ye et al, 2008). The liquid crystals are accompanied by a pinhole mechanism to increase the depth of focus.

Sports Enhancement

Contact lenses with varying tints have been investigated as a way to improve athletes’ performance (Cerviño et al, 2008). A permanent tint or active tinting may aid an athlete’s ability to adjust to different light levels and decrease glare while playing their sport. However, more research is required to verify these benefits.

Low Vision Enhancements

A Galilean telescope can be achieved by combining a high-powered negative contact lens and a neutralizing lens in the spectacle plane to provide magnification for low-vision patients. Advancements in the capability to switch between magnification and non-magnification using polarization are underway (Tremblay et al, 2013).

Augmented Reality

Augmented reality (AR) is exploring opportunities to aid mobility and independence for patients who have low vision by enhancing selected edges and distances. It is predicted that in the future, AR lenses will incorporate optical zoom, the ability to scroll information and texts, translate languages, or provide visual prompts to a public speaker.

An obstacle for AR contact lenses is that they require an external battery and reciever, and dependency on background brightness specifically in ambient lighting conditions. (Martin, 2020). Currently, only prototypes have been produced (Chen et al, 2019). CLS

REFERENCES

1. Wolffsohn JS, Calossi A, Cho P, et al. Global trends in myopia management attitudes and strategies in clinical practice - 2019 Update. Cont Lens Anterior Eye. 2020 Feb;43:9-17.
2. Jonas JB, Ang M, Cho P, et al. IMI Prevention of Myopia and Its Progression. Invest Ophthalmol Vis Sci. 2021 Apr 28;62:6.
3. Richdale K, Cox I, Kollbaum P, et al. CLEAR - Contact lens optics. Cont Lens Anterior Eye. 2021 Apr;44:220-239.
4. Vincent SJ, Cho P, Chan KY, et al. CLEAR - Orthokeratology. Cont Lens Anterior Eye. 2021 Apr;44:240-269.
5. Erdinest N, London N, Levinger N, Morad Y. Myopia Control with Combination Low-Dose Atropine and Peripheral Defocus Soft Contact Lenses: A Case Series. Case Rep Ophthalmol. 2021 Jun 14;12:548-554.
6. Gao C, Wan S, Zhang Y, Han J. The Efficacy of Atropine Combined With Orthokeratology in Slowing Axial Elongation of Myopia Children: A Meta-Analysis. Eye Contact Lens. 2021 Feb 1;47:98-103.
7. Jinabhai AN. Customised aberration-controlling corrections for keratoconic patients using contact lenses. Clin Exp Optom. 2020 Jan;103:31-43.
8. Marsack JD, Rozema JJ, Koppen C, Tassignon MJ, Applegate RA. Template-based correction of high-order aberration in keratoconus. Optom Vis Sci. 2013 Apr;90:324-334.
9. Legras R, Chateau N, Charman WN. Assessment of just-noticeable differences for refractive errors and spherical aberration using visual simulation. Optom Vis Sci. 2004 Sep;81:718-728.
10. Rae SM, Price HC. The effect of soft contact lens wear and time from blink on wavefront aberration measurement variation. Clin Exp Optom. 2009 May;92:274-282.
11. Bailey J, Morgan PB, Gleeson HF, Jones JC. Switchable Liquid Crystal Contact Lenses for the Correction of Presbyopia. Crystals. 2018;8(1):29.
12. Win-Hall DM. Accommodating or focusable contact lens. Google Patents. #US7866815B2. Granted 2011 Nov 1. Available at patents.google.com/patent/US7866815B2/en . Accessed Oct. 25, 2022.
13. Biederman WJ, Yeager D, Otis B, Pletcher N. Capacitive gaze tracking for auto-accommodation in a contact lens. Google Patents. #US10495904B2. Granted 2016 Aug 13. Available at patents.google.com/patent/US9442310B2/en . Accessed Oct. 13, 2022.
14. Egan W, Nibauer L. Fluid filled adjustable contact lenses. Google Patents #US9500884B2. Granted 2016 Nov 22. Available at patents.google.com/patent/US9500884B2/en?oq=US9500884B2 . Accessed Oct. 13, 2022.
15. Ye M, Wang B, Sato S. Realization of liquid crystal lens of large aperture and low driving voltages using thin layer of weakly conductive material. Opt Express. 2008 Mar 17;16:4302-4308.
16. Cerviño A, Gonzalez-Meijome JM, Linhares JMM, Hosking SL, Montes-Mico R. Effect of sport-tinted contact lenses for contrast enhancement on retinal straylight measurements. Ophthalmic Physiol Opt. 2008 Mar;28:151-156.
17. Tremblay EJ, Stamenov I, Beer RD, Arianpour A, Ford JE. Switchable telescopic contact lens. Opt Express. 2013 Jul 1;21:15980-15986.
18. Martin PS. Mojo vision nanoLEDs for invisible computing. Proc SPIE 11302, Light -Emitting Devices, Materials and Applications XXIV, 1130204. 2020 Feb 25.
19. Chen J, Mi L, Chen CP, Liu H, Jiang J, Zhang W. Design of foveated contact lens display for augmented reality. Opt Express. 2019 Dec 23;27:38204-38219.