Opaque bubble layer and possible sequelae
One of the most common adverse effects of the intrastromal photo-disruption procedure is the generation of opaque bubble layer (OBL). This bubble layer, created as a result of tissue disruption by the femtosecond laser, is composed of carbon dioxide and water. Laser tracking systems can be significantly impaired by the OBL. Time and/or mechanical massage will allow for OBL to dissipate. Newer-generation femtosecond lasers with higher repetition rates tend to create fewer OBLs.
Figure 6-17 Blood in the LASIK interface.
(Courtesy of Jayne S. Weiss, MD.)
Epithelial gas breakthrough is a rare but serious complication of OBL production. Similar to a buttonhole from a mechanical keratome, the breakthrough should be allowed to heal and stabilize generally for at least 3 months, at which time surface ablation may be considered.
In rare cases, the gas liberated from the plasma cavitations can travel into the anterior chamber, potentially interfering with the laser tracking systems. If this occurs, the surgeon can allow a few hours for the bubbles to resolve. In addition, instillation of a mydriatic drop may allow the pupil to begin to dilate around the bubbles, which can allow laser recognition and capture.
Kaiserman I, Maresky HS, Bahar I, Rootman DS. Incidence, possible risk factors, and potential effects of an opaque bubble layer created by a femtosecond laser. J Cataract Refract Surg. 2008;34(3):417–423.
Transient light sensitivity
Several weeks to months after LASIK with femtosecond laser flaps, some patients experience acute onset of pain and light sensitivity in an otherwise white and quiet eye with excellent uncorrected visual acuity (UCVA; also called uncorrected distance visual acuity, UDVA). The cornea and flap interface appear normal. It has been speculated that an acute onset of ocular inflammation or dry eyes is somehow related to use of the femtosecond laser. Treatment consists of frequent administration of topical corticosteroids (eg, prednisolone acetate, 1%, every 2 hours) and topical cyclosporine A, titrated to the clinical condition. Almost all cases respond to treatment and resolve in weeks to months.
Rainbow glare, an optical adverse effect of treatment with the femtosecond laser, is described as bands of color around white lights at night. This complication seems to be related to higher raster energy levels and increased length of time between service calls for the laser.
Farjo AA, Sugar A, Schallhorn SC, et al. Femtosecond lasers for LASIK flap creation: a report by the American Academy of Ophthalmology. Ophthalmology. 2013;120(3):e5–e20.
Krueger RR, Thornton IL, Xu M, Bor Z, van den Berg TJ. Rainbow glare as an optical side effect of IntraLASIK. Ophthalmology. 2008;115(7):1187–1195.
Excerpted from BCSC 2020-2021 series: Section 13 - Refractive Surgery. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.