Research Article
Extrusion of Femtosecond Laser-Implanted Intrastromal Corneal Ring Segments in Keratoconic Eyes: Prevalence, Risk Factors, and Clinical Outcomes
Table 4
Comparison of presumable risk factors between eyes with and without ring extrusion.
| | | Eyes with ring extrusion (n = 7) | Eyes with no extrusion (n = 326) | value |
| | Atopic association | 3 (42.9%) | 144 (44.1%) | 0.33 | | Chronic sun exposure | 5 (71.4%) | 216 (66.3%) | 0.085 | | Dry eye severity level | | | | | 0 | — | 48 (14.7%) | | | 1 | — | 50 (15.3%) | | | 2 | 3 (42.9%) | 120 (36.8%) | 0.044 | | 3 | 4 (57.1%) | 108 (33.1%) | 0.03 | | Stage of KC | | | | | Stage 1 | — | 84 (25.8%) | | | Stage 2 | — | 112 (34.4%) | | | Stage 3 | 7 (100%) | 130 (39.9%) | 0.02 | | K max | | | | | <55 D | — | 84 (25.8%) | | | 55–62 D | 5 (71.4%) | 144 (44.2%) | 0.052 | | >62 D | 2 (28.6%) | 98 (30.1%) | 0.063 | | Cone position | | | | | Central | — | 219 (67.2%) | | | Eccentric | 7 (100%) | 107 (32.8%) | 0.001 | | Number of rings | | | | | One ring | — | 194 (59.5%) | 0.82 | | Two rings | 7 (100%) | 132 (40.5%) | 0.001 | | Ring thickness | | | | | 300 | 8 (57.1%) | 128 (27.9%) | 0.03 | | 250 | 6 (42.8%) | 219 (47.8%) | 0.087 | | 200 | — | 111 (24.2%) | | | Ring arc | | | | | 90 | 3 (21.4%) | 105 (22.9%) | 0.33 | | 160 | 9 (64.2%) | 288 (62.9%) | 0.05 | | 210 | 2 (14.2%) | 65 (14.2%) | 0.063 | | Same session CXL | 6 (85.7%) | 241 (73.9%) | 0.01 |
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