Laboratory evaluation of a novel technique for myopia correction: Continuous wave laser (CWL) cornea shrinkage coupled with CXL

Article

Continuous wave laser (CWL) cornea shrinkage coupled with CXL

Herein, we report a novel thermal reshaping application where a continuous wave midIR laser is used to create collagen shrinkage midstromally, fully sparing the corneal epithelium (and endothelium) and to a large extent, the Bowmans membrane, secondarily applying high irradiance UV light with a custom (transepithelial) riboflavin formulation for rapid collagen crosslinking to stiffen collagen for durability/persistence of this refractive effect in a laboratory model.

Methods and technique

The TS-RXL delivery system consisted of a midIR (2013 nm) laser, fibre coupled to a PC-controlled scanner, delivering a focused spot (~600 µm diameter) onto the cornea through an applanating chilled sapphire lens. The chilled lens is housed in a cone assembly on the articulating arm. The temperature of the sapphire lens was settable and was cooled to ~8 °C. The TS-RXL arm was lowered to applanate the cornea. During this process, the cornea under illumination was directly visualized by the operator through the superior opening of the cone; and on a PC image fed from the video camera. Ring diameters, sequence of patterns, along with speed and power were settable on the PC screen by the surgeon. As a result of extensive flexibility in parameter selection (lesion depth/diameter/draw speed/sequence/opacification control), significant precision of outcomes (Dioptres of correction) was provided by the device.

Following an applanated cooling period of 30 seconds, the treatment was started under footswitch control. It should be noted that the key parameters of the laser application (power, speed, ring diameters, ring sequence) were surgeon specified at the start of each exposure. The surgeon could select one, two, three, up to seven ring applications in sequence. These rings can be placed anywhere on the applanated surface of the cornea (including selectively and precisely decentred) Intraring distance was set per surgeon's preference. Based on preliminary unpublished work that we have done with this device for correction of myopia, we decided to place the 3 sub-surface lesional rings at 3, 4 and 5 mm diameters, each ~80 µm deep, centred on the cornea.

The device was footswitch activated and each ring was created by the continuous wave laser, applying the laser energy in a circular fashion counter clockwise, to create a complete circular sub-surface annulur ring lesion. First, the 3 mm diameter ring was completed, then the 4 mm and finally the 5 mm ring was completed. The duration for laser application for each ring took about 4 seconds, and the total applanation duration of the lens on the cornea lasted about one minute (30 seconds chill+12 seconds Sx+15 seconds chill). The system is designed to provide constant but selectable linear draw speeds at each diameter thus inducing a uniform quality of lesion. Following IR laser delivery, the cooling continued for 15 seconds.

Newsletter

Join ophthalmologists across Europe—sign up for exclusive updates and innovations in surgical techniques and clinical care.

Recent Videos
Alfredo Sadun, MD, PhD, chief of Ophthalmology at the Doheny Eye Institute, University of California Los Angeles, shared exciting new research with the Eye Care Network during the Association for Research in Vision and Ophthalmology (ARVO) meeting on the subject of Leber hereditary optic neuropathy (LHON).
At this year's Association for Research in Vision and Ophthalmology (ARVO) meeting in Salt Lake City, Utah, Nitish Mehta, MD, shared highlights from his research documenting real-world results of aflibercept 8 mg for patients with diabetic macular oedema.
ARVO 2025: Anat Loewenstein, MD, shares data from herself and her colleagues on meeting needs of patients with diabetic retinopathy
At the American Society of Cataract and Refractive Surgeons annual meeting, Sheng Lim, MD, FRCOphth discusses the benefit of endoscopic cyclophotocoagulation for patients with primary open angle glaucoma and cataracts in the CONCEPT study
A photo of Seville, Spain, with the Congress on Controversies in Ophthalmology logo superimposed on it. Image credit: ©francovolpato – stock.adobe.com; logo courtesy COPHy
Anat Loewenstein, MD, Professor and Director, Department of Ophthalmology, Tel Aviv Medical Center, discusses the Congress on Controversies in Ophthalmology (COPHy)
(Image credit: Ophthalmology Times Europe) AGS 2025: Clemens Strohmaier, PhD, on improving aqueous humour outflow following excimer laser trabeculostomy
3 experts are featured in this series.
Anat Loewenstein, MD, speaks about the 22nd Annual Angiogenesis, Exudation, and Degeneration Meeting in February 2025 and shares her global forecast for AI-driven home OCT
3 experts are featured in this series.
Related Content
© 2025 MJH Life Sciences

All rights reserved.