Long-Term Outcomes of Intrastromal Corneal Ring Segment Explantation in Keratoconus Patients
The purpose of this study is to assess the causes for intrastromal corneal ring segment (Intacs, Addition Technology Inc.) explantation in patients with keratoconus, as well as technique for explantation, long-term outcomes, and further procedures to correct visual acuity.
Ten eyes of 8 patients with a history of Intacs explantation between 2004 and 2012 were included in a retrospective study performed at Bascom Palmer Eye Institute in Miami, Florida. Reasons for Intacs removal, surgical technique, pre-operative and post-operative corneal examination, and uncorrected and best-corrected visual acuity (UCVA and BCVA) were documented. Additionally, corneal topography (Tomey) parameters such as average keratometry (avgK) and corneal cylinder (CC) were assessed. Statistical analysis was performed using SPSS software (version 22).
The most common reason for Intacs removal was worsening visual acuity (80%), even though the segments were well positioned. There was no statistically significant difference between pre-Intacs placement, post-Intacs placement, and post-Intacs removal UCVA, BCVA, AvgK, or CC, other than between 1 year post-Intacs placement BCVA (0.57logMAR) and 1 month post-Intacs removal BCVA (0.25logMAR) p=0.03. Four patients went on to have PK after Intacs removal with good visual outcomes.
This study demonstrated visual and structural outcomes that returned to near baseline after Intacs explantation in keratoconus patients.