Femtosecond-assisted intracorneal ring segment complications in keratoconus: from novelty to expertise

Figures & data

Table 1 Shows the main refractive outcomes over 18 months of follow-up

	Preoperative	Postoperative (18 months)	p-value
UCVA	1.31±0.24	1.1±0.21	0.002
BCVA	0.79±0.24	0.72±0.02	0.19
Sphere	−7.6±5.29	−5.16±4.01	0.0003
Cylinder	−6.53±3.25	−4.73±1.74	0.03
SER	−10.86±5.71	−7.52±3.97	0.0001
K1	49.13±3.13	46.88±2.69	<0.0001
K2	53.50±4.46	49.83±3.18	<0.0001
Mean keratometry	51.31±3.68	48.35±2.84	<0.0001
Mean thinnest location	428.5±26.25	421.85±30.09	0.13

Abbreviations: BCVA, best-corrected visual acuity; SER, spherical equivalent refractive error; UCVA, uncorrected visual acuity.

Table 2 Intraoperative and postoperative complications of femtosecond-assisted intracorneal stromal ring

	Overall rate of complication (623 eyes)	First-year rate of complication (122 eyes)	Second-year rate of complication (130 eyes)	Third-year rate of complication (177 eyes)	Fourth-year rate of complication (194 eyes)
Intraoperative complications
Vacuum loss	8	5	1	2	1
Incomplete tunnel creation	6	3	2	1	0
Decentered created tunnel	7	4	1	1	1
Misdirection of ring segment into stroma	6	3	2	1	0
Perforation into anterior chamber	1	1	0	0	0
Inverted implanted rings	7	3	2	1	1
Broken body of Keraring	6	3	1	1	0
Broken end orifice of ring	3	1	1	1	0
Postoperative complications
Segment migration	10	5	2	2	1
Segment extrusion	4	1	2	1	0
Incision opacification	4	1	2	1	1
Infective keratitis	4	2	1	1	0
Corneal melting	1	1	0	0	0
Sterile keratitis	5	1	1	2	1
Steroid-induced glaucoma	4	1	2	1	0

Figure 1 (A) Scheimpflug tomography by Sirius CSO showing decentered ring. (B) Scheimpflug image of the cornea showing decentered rings near toward the pupil. (C) Cornea view of the eye showing the Keraring crossing the pupil.

Figure 2 (A) Signs of infection in the presence of Kerarings. (B) Explantation of Keraring. (C) Postexplantation corneal scarring.

Figure 3 Crystalline deposits around the Keraring.