1. Prospective Study of Intrastromal Corneal Ring Segments for Keratoconus Scott X. Stevens, MD Bend Ophthalmology, LLC Author has no financial interest.

2. Purpose Keratoconus is an abnormal thinning of the central and inferior paracentral cornea and is a frequent indication for penetrating keratoplasty. Long-term risks have prompted intrastromal ring segments as an alternative. A prospective independent clinical study was initiated for patients with keratoconus or post-LASIK ectasia. Prospective Study of Intrastromal Corneal Ring Segments for Keratoconus

3. Methods FDA HDE guidelines established in 2004 were utilized in this independent clinical study. The study was initiated February, 2004. An IRB for the surgeon has been in place. The HDE guidelines directed that an eye with less than -3D spherical equivalent have a 0.25 ring placed superiorly and a 0.30 ring placed inferiorly. Patient eyes with more than -3D spherical equivalent have a 0.30 ring placed superiorly and a 0.35 ring placed inferiorly. The rings are 160 o and placed at the 7mm optical zone. All surgeries were completed by the author. Eyes with central corneal scarring were excluded from enrollment. Temporal corneal pachymetry was >450 microns. UCVA, BCVA, Keratometry, corneal topography, central corneal pachymetry were acquired. All eyes had become contact lens intolerant. Baseline BCVA included piggyback/ gas-permeable contact lens over-refraction at enrollment. BCVA post-op was acquired with the patient’s everyday visual aid (ie glasses, contact lens, manifest refraction). Lasik-ectasia eyes were treated in the same fashion as keratoconus eyes. FDA HDE guidelines established in 2004 were utilized in this independent clinical study. The study was initiated February, 2004. An IRB for the surgeon has been in place. The HDE guidelines directed that an eye with less than -3D spherical equivalent have a 0.25 ring placed superiorly and a 0.30 ring placed inferiorly. Patient eyes with more than -3D spherical equivalent have a 0.30 ring placed superiorly and a 0.35 ring placed inferiorly. The rings are 160 o and placed at the 7mm optical zone. All surgeries were completed by the author. Eyes with central corneal scarring were excluded from enrollment. Temporal corneal pachymetry was >450 microns. UCVA, BCVA, Keratometry, corneal topography, central corneal pachymetry were acquired. All eyes had become contact lens intolerant. Baseline BCVA included piggyback/ gas-permeable contact lens over-refraction at enrollment. BCVA post-op was acquired with the patient’s everyday visual aid (ie glasses, contact lens, manifest refraction). Lasik-ectasia eyes were treated in the same fashion as keratoconus eyes. Prospective Study of Intrastromal Corneal Ring Segments for Keratoconus

4. Methods Fifty-three eyes have been enrolled to date. Fifty-three eyes have been enrolled to date. 5 eyes are no-longer enrolled. Two patients (2 eyes) have failed to make any follow-up visits. One eye 3-months post- op with LASIK-ectasia had the LASIK flap removed by an ER physician requiring DALK to restore vision (currently BCVA=20/20). One patient lost his eye secondary to blunt trauma. The final eye was removed from the study secondary to eye-rubbing which required removal of the ring segments as they were exposed for one week. 5 eyes are no-longer enrolled. Two patients (2 eyes) have failed to make any follow-up visits. One eye 3-months post- op with LASIK-ectasia had the LASIK flap removed by an ER physician requiring DALK to restore vision (currently BCVA=20/20). One patient lost his eye secondary to blunt trauma. The final eye was removed from the study secondary to eye-rubbing which required removal of the ring segments as they were exposed for one week. Visual acuity is the outcome variable. UCVA and BCVA are presented at Baseline, 6-months, 1-year and 2-year gates. Statistical comparison was accomplished using a matched t-test. Visual acuity is the outcome variable. UCVA and BCVA are presented at Baseline, 6-months, 1-year and 2-year gates. Statistical comparison was accomplished using a matched t-test. Prospective Study of Intrastromal Corneal Ring Segments for Keratoconus

5. Results Baseline = 20/260 6-Month = 20/140 t=6.2775, p<0.01

6. Results Prospective Study of Intrastromal Corneal Ring Segments for Keratoconus

7. Results Baseline = 20/230 2-Year = 20/120 t=7.2307, p<0.01

8. Results Prospective Study of Intrastromal Corneal Ring Segments for Keratoconus 36.1% are 20/20 or better 77.8% are 20/25 or better 83.4% are 20/30 or better 94.5% are 20/40 or better

9. Results Prospective Study of Intrastromal Corneal Ring Segments for Keratoconus 71.0% are 20/20 or better 86.8% are 20/25 or better 94.7% are 20/30 or better 100% are 20/40 or better t=8.6634, p<0.01

10. Results Prospective Study of Intrastromal Corneal Ring Segments for Keratoconus 73.7% are 20/20 or better 89.9% are 20/25 or better 100% are 20/30 or better

11. Results 3 eyes lost 1 line of BCVA from Baseline to 6-months. 7 eyes had no improvement. 3 eyes lost 1 line of BCVA from Baseline to 6-months. 7 eyes had no improvement. 20/30 – 20/40 (n=2) 20/30 – 20/40 (n=2) 20/25 – 20/30 (n=1) 20/25 – 20/30 (n=1) 1 eye lost 2 lines of BCVA from Baseline to 1-Year. All remaining eyes improved by at least one line. 1 eye lost 2 lines of BCVA from Baseline to 1-Year. All remaining eyes improved by at least one line. 20/25-20/40 (n=1) 20/25-20/40 (n=1) 1 eye lost 1 line of BCVA from Baseline to 2-Year. All remaining eyes improved by at least one line. 1 eye lost 1 line of BCVA from Baseline to 2-Year. All remaining eyes improved by at least one line. 20/25 – 20/30 (n=1) 20/25 – 20/30 (n=1) Prospective Study of Intrastromal Corneal Ring Segments for Keratoconus

12. Conclusions Intrastromal ring segments significantly improve UCVA and BCVA at every gate (p<0.01) Intrastromal ring segments significantly improve UCVA and BCVA at every gate (p<0.01) BCVA improves over time. BCVA improves over time. At the 2-year gate (n=38), BCVA is 20/30 or better in all eyes. Seventy-three percent are 20/20 or better. At the 2-year gate (n=38), BCVA is 20/30 or better in all eyes. Seventy-three percent are 20/20 or better. One eye has needed DALK to repair the damage from removal of the LASIK flap. The eye was 20/16 BCVA prior to the event and currently sees 20/20 BCVA. One eye has needed DALK to repair the damage from removal of the LASIK flap. The eye was 20/16 BCVA prior to the event and currently sees 20/20 BCVA. No eye has needed penetrating keratoplasty to date. No eye has needed penetrating keratoplasty to date. Prospective Study of Intrastromal Corneal Ring Segments for Keratoconus