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How Night Contacts Work and Their Benefits

Updated: Jul 3, 2023

Author: Emily Jiang

Editors: Yanxi Chen, Emily Chen, and Jaylen Peng

Artists: Serena Yung

Many people have heard of glasses, regular contact lenses, or LASIK eye surgery as the more well-known methods to correct vision. Currently, the use of ortho-K lenses makes up a small fraction of patients that wear lenses, constituting only 1.2% of contact lens fittings worldwide. However, the market is expected to grow and expand over the next several years. Ortho-K (Orthokeratology) employs the use of gas-permeable lenses to reshape the cornea in order to temporarily improve eyesight. They are mainly worn at night when the user is asleep, with consistent use necessary to maintain quality vision, reverting back to its original state within 72 hours.

The eye functions by detecting when light passes through the retina. The rods and cones within the retina absorb the light and transmit a lucid image to the optic nerve before it transfers to the brain's visual cortex. This only works properly if the eye maintains a particular shape, so the distance from the lens to the retina stays a definite length. Imperfections in the shape and curvature of the cornea can cause eyeomyopia, hyperopia, or astigmatism to occur as forms of refractive errors. Myopia, or nearsightedness, causes flawed vision from a distance but clearer sight up close. This is the result when the distance from the cornea to the retina is larger than usual, causing light to converge in and focus earlier, resulting in blurry vision when the light hits the retina. For Hyperopia, or farsightedness, where you cannot focus on close objects, the eye is smaller. Astigmatism is where the corneas are misshapen.

So, how do Ortho-K lenses help and fit? They act as a mold to reshape the flexible tissues of the cornea and slow or stop myopia development. The lenses help fix how light is bent when it enters the cornea by flattening the center of the cornea, but they still allow oxygen to transmit through the lenses so the eye stays safe and healthy. In order to find suitible Ortho-K lenses for your eyes, your ophthalmologist uses a corneal topographer, which helps the ophthalmologist map and measure the cornea's surface. The cornea map is used to navigate the intricacies of eye curvature, and is created by analyzing how light is reflected off the cornea's surface. Overall, the corneal topographer examines patients’ corneal curvature to determine the appropriate lens design to use, ultimately forecasting the projection of the ortho-k treatment.

There are many benefits to wearing ortho-k. In clinical studies of the FDA, most patients – roughly 95% – achieved 20/40 vision or better, followed by 73% of the patients who achieved 20/20 vision or better. The lenses cost half the price of laser vision correction and significantly control the development of bad eyesight, especially in children with myopia. This is a suitable alternative for swimmers and athletes, as you won’t need to wear the lenses during the day, as well as for people who are not qualified for LASIK eye surgery due to thin/irregular corneas, have severely dry eyes, unstable vision, or high refractive errors. You must be a minimum of 18 years old to get LASIK surgery, so this is also an excellent alternative for younger people.

Ortho-K/night contacts are incredibly beneficial for many people, from those who need it, to those who simply dislike wearing anything on their face or eyes during the day. With more recent technology, it is very easy to fit and functions incredibly well.

 

Citations:

“Is Orthokeratology a Dying Art?” Modern Optometry, Bryn Mawr Communications, Chan, Kevin,

“How Do Eye Shapes Affect Vision?” LASIK MD, 11 March 2014, LASIK MD, https://www.lasikmd.com/blog/eye-shapes-affect-vision.

“Ortho-K: Top 10 Faqs.” Optometrists.org, Lazarus, Russel, 1996-2022 Optometrists Network-

Powered by EyeCarePro, 19 July 2021, https://www.optometrists.org/general-practice-

optometry/guide-to-myopia-management/ortho-k-top-10-faqs/.

“What is Orthokeratology?” American Academy of Ophthalmology, Mukamal, Reena, American

Academy of Ophthalmology 2022, 24 Oct. 2018, https://www.aao.org/eye-health/glasses-

contacts/what-is-orthokeratology.

“Ortho-K Lens Market Expects Growth in next Few Years.” Review of Optometry, Staff, Ortho-K

Lens Market Growth, Jobson Medical Information LLC, 10 June 2022,

few-years.

“Therapy with Ortho K Lenses.” Myopia Institute, Myopia Institute, Therapy with Ortho K Lenses, 9

lenses/#:~:text=The%20first%20orthokeratology%20lenses%20.

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