Long-term Follow-up for Intrastromal Cornea Ring Segments in Early to

Severe Keratoconic Patients

Omer Trivizki 1,Eliya Levinger 1,2, Irit Bareqet 2, Ami Hirsh 2, Israel Kremer 2, Shmuel Levinger 2

1 Department of ophthalmology, Tel Aviv Medical Center, Israel2 Enaim Medical Center, Jerusalem, Israel

I have no financial interests or relationships to disclose

Purpose

To report the safety and the efficacy of a long term follow-up of intrastromal corneal ring segments (ICRS) implantation in early to severe keratoconic patients

Methods

• Retrospective nonrandomized study• PMMA, crescent-shaped arc length of 150 degrees, Inner diameter is

6.8 mm and the outer diameter is 8.1 millimeter• ICRS were implanted using either by femtosecond laser technique• The evaluation included:

• Uncorrected distance visual acuity (UDVA) • Corrected distance visual acuity (CDVA)• Refraction• Average keratometric values

Results• The study included 221 keratokonic eyes of 221 patients• Median age 32.17 ± 8.94, 124 males• 154 (69%) of the procedures were made using femtosecond laser and

inasmuch as only 67 were done manually• Mean follow-up period was 26.8 ± 30 months ranging between 1 to

148 months• Patients were grouped according to keratoconus stage

Results• There was a statistically significant improvement in postoperative

LogMAR UDVA of more than 3 lines from 0.95 ± 0.40 to 0.64 ± 0.37 (P <

0.005), respectively• Mean LogMAR CDVA was changed from 0.29 ± 0.30 to 0.38 ± 0.40

(P=0.85)

Change in the UCVA after Intacs implantation Change in the BCVA after Intacs implantation

Results

• The mean spherical equivalent (SEQ) was -3.36 diopters (D) preoperatively and -1.20 D postoperatively (P<0.005)

• Average keratometry decreased by 2.2 D from 47.08 ± 3.12 to 44.82 ± 3.48 (P<0.001)

Change in cylindrical refraction post-implantation Change in spherical refraction post-implantation

Results

• The mean spherical equivalent (SEQ) was -3.36 diopters (D) preoperatively and -1.20 D postoperatively (P<0.005)

• Average keratometry decreased by 2.2 D from 47.08 ± 3.12 to 44.82 ± 3.48 (P<0.001)

Change in cylindrical refraction post-implantation Change in spherical refraction post-implantation

Results

Stage post-implantation Total (%)

1 2 3 4Stage pre-

implantation1 117 4 2 0 123 (55.5%)2 22 21 11 11 51 (23.2%)3 5 11 3 3 22 (10%)4 1 11 2 11 25 (11.4%)

Total (%) 144 (65.5%) 47 (21.4%) 12 (5.45%) 17 (7.73%) 221

• Change in keratoconus stage post-implantation according Amsler-Krumeich Classification for Grading KeratoconusƗ

• Most did not change, 52 improved, 31 deteriorate• Improvement was found statistically significant in the female group (p<0.001)

Ɨ Ophthalmologica. 1946 Feb-Mar;111(2-3):96-101.

Results

• Change in VA and refraction post-op, grouped by initial according Amsler-Krumeich ClassificationƗ

• VA improved in all groups, so did refraction values• Yet, it was found statistical significant only in stage 1 disease (p<0.001)

Ɨ Ophthalmologica. 1946 Feb-Mar;111(2-3):96-101.

Complications

Change ring location 5Adding segment 13Removing segment 8Removing rings 4Cornea transplantation 1Total 31

• 31 patients needed re-operation for ring change (Table 1)• 1 patient needed corneal transplantation• 65 patients needed a secondery refraction surgery (Table 2)

Table 1 Table 2LASEK+ CROSSLINK 41

LASEK 18PRK 2ICL 4

Total 65

Conclusion

• As far to our knowledge, this is the first study evaluating effectiveness of ICRS for such a long term follow-up period

• ICRS implantation is both safe and efficient in keratoconus management over the long-term period of time