Long-Term Follow-Up of Intrastromal Corneal Ring Segments in Paracentral Keratoconus with Coincident Corneal Keratometric, Comatic, and Refractive Axes: Stability of the Procedure

Table 1

Patients’ demographics: age, pre-ICRS implantation spherical equivalent (SE), manifest refraction (refractive sphere and cylinder), undistance visual acuity (UDVA) (logMAR scale), corrected distance visual acuity (CDVA) (logMAR scale) pre-keratometry (K) value, and root mean square (RMS) for coma-like aberration shown as mean ± standard deviation (SD) and range.

Characteristic	Whole sample	Group I (younger patients)	Group II (older patients)
Eyes (n)	58	23	35
Age (years)	34 ± 9.2	25.35 ± 3.88	40.23 ± 6.56
Mean SE (D)	−2.74 ± 3.38	−3.32 ± 4.57	−2.36 ± 2.30
Mean refractive sphere (D)	−0.50 ± 3.24	−1.08 ± 4.45	−0.22 ± 2.11
Mean refractive cylinder (D)	−4.36 ± 1.87	−4.49 ± 2.02	−4.28 ± 1.78
UDVA (logMAR)	0.83 ± 0.31	0.90 ± 0.31	0.74 ± 0.32
CDVA (logMAR)	0.16 ± 0.17	0.18 ± 0.13	0.10 ± 0.20
Mean K minimum (D)	44.41 ± 3.08	44.00 ± 2.52	44.62 ± 3.47
Range K minimum (D)	39.25 to 53	40 to 49.75	39.25 to 53
Mean K maximum (D)	48.65 ± 3.63	48.79 ± 2.84	48.46 ± 4.11
Range K maximum (D)	42.50 to 58	44.25 to 55.5	42.50 to 58
RMS for coma-like for 4.5 mm of pupil size (μm)	1.03 ± 0.65	0.96 ± 0.65	1.12 ± 0.60
Range RMS for coma-like (μm)	0.1 to 2.23	0.1 to 2.23	0.1 to 2.08

Statistically significant between groups.