Changes in Retinal Vasculature and Thickness after Small Incision Lenticule Extraction with Optical Coherence Tomography Angiography.

Minjie Chen,Jinhui Dai,Lan Gong

doi:10.1155/2019/3693140

Minjie Chen, Jinhui Dai + Show 1 more

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https://doi.org/10.1155/2019/3693140

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Abstract

Purpose To evaluate the changes in retinal vessel density and thickness after small incision lenticule extraction (SMILE) with optical coherence tomography angiography (OCTA) in myopic patients. Methods In this prospective study, SMILE surgeries were done in 46 eyes of 24 patients with spherical equivalent (SE) more than −6.0 diopters (D). Retinal vessel density and thickness at the macula and optic nerve were recorded with OCTA before and 1 day, 2 weeks, and 1 month after surgery. Intraocular pressure (IOP), uncorrected distance visual acuity (UDVA), and refraction were taken at the same time. Results The superficial retinal vessel density and deep foveal retinal vessel density 1 day after surgery were less than those before surgery; however, the changes at any timepoints were not statistically significant (p=0.2736 and p=0.1590, respectively). Both the superficial vessel density and deep vessel density at the parafoveal and perifoveal regions decreased significantly 1 day postoperatively (all p < 0.05) and then returned to the preoperative level at 2 weeks and stabilized thereafter. There were no significant changes in any of the 4 vessel densities in the area of peripapillary before and 1 day, 2 weeks, and 1 month after surgery (p=0.3345). No statistically significant differences between preoperative and postoperative retinal thickness were detected for the area of macula and optic nerve (all p > 0.5). Conclusions The vessel density at the parafoveal and perifoveal regions decreased at 1 day after SMILE with no effect on the visual acuity and relieved within 2 weeks. Decreased ocular blood flow in response to the spike in IOP may account for such changes.

Highlights

Femtosecond laser-assisted corneal refractive surgeries hold major part in treating refractive errors nowadays
Previous studies have shown intraocular pressure (IOP) increased during suction-mediated application of the glass contact, which is used in flap creation and refractive cut during the femtosecond laser-assisted laser in situ keratomileusis (FSLASIK) and femtosecond lenticule extraction (FLEx) and even femtosecond laser-assisted cataract surgery [1,2,3]. e sudden spike in IOP to levels exceeding 65 mmHg, which can damage the eye, has been observed during the traditional microkeratome flap creation of laser in situ keratomileusis (LASIK) [4, 5]
It is suggested that acute increases in IOP can induce ischemia-reperfusion injury, which may cause retinal ganglion cell death as well as damage to the optic nerve and retina [8, 9]. ough most researchers showed suction had no significant clinical effects on the macular and retinal nerve fiber layer (RNFL) thickness during FS-LASIK or FLEx [10,11,12], macular hemorrhage after FS-LASIK was reported in a patient with a moderate Journal of Ophthalmology degree of myopia and no macular pathology [13]. us, the effect of sudden spike in IOP on the retina caused by suction during the femtosecond laser procedures is still a widespread concern among ophthalmologists

Summary

Introduction

Femtosecond laser-assisted corneal refractive surgeries hold major part in treating refractive errors nowadays. During these procedures, vacuum suction is inevitable. Previous studies have shown intraocular pressure (IOP) increased during suction-mediated application of the glass contact, which is used in flap creation and refractive cut during the femtosecond laser-assisted laser in situ keratomileusis (FSLASIK) and femtosecond lenticule extraction (FLEx) and even femtosecond laser-assisted cataract surgery [1,2,3]. Us, the effect of sudden spike in IOP on the retina caused by suction during the femtosecond laser procedures is still a widespread concern among ophthalmologists. Whether the sudden spike in IOP and the lenticule separation during SMILE damage the retina remains unknown. Shoji et al showed that a change in retinal vessel density could be detected before a change in ganglion cell complex (GCC) thickness occurs [17]

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