Algorithmic Approach For Planning Toric Implantable Collamer Lens In Keratoconus

To develop an algorithmic approach for accurate planning of Toric Implantable Collamer Lens (TICL) implantation in eyes with Keratoconus (KC).

All patients had undergone pre-operative work-up and procedures at Narayana Nethralaya Eye Hospital, Bangalore, India.

35 eyes of 21 keratoconus patients who underwent TICL implantation were studied retrospectively. 5 patients had decentered cones and had undergone intrastromal corneal ring (INTACS) placement procedures. The cornea of 10 patients with high higher order aberrations was first regularized with topography-guided PRK along with collagen cross-linking. 15 keratoconus patients with contact lens intolerence were taken. Keratoconic stability on topography for atleast 2 years was ensured prior to TICL implantation. A thorough retina, glaucoma and strabismus evaluation was done. Patient’s corneal topography, epithelial mapping, aberrometry, anterior segment OCT along with best corrected visual acuity pre and post-TICL was noted for analysis.

A decrease in MRSE was noted from preoperative – 7.79 ± 4.75D to − 0.52 ± 0.90 D at 2 year follow-up. There was a significant increase in best corrected visual acuity post-operatively (P<0.0001). The pre-operative mean cylinder of - 4.48 ± 2.24 D was found to be - 0.98 ± 0.84 D on post-operative follow-up at 2 years. Out of 35 eyes, 18 showed no change, 11 gained 1 line and 6 gained 2 lines on snellen’s visual acuity test and none of the eyes showed any loss of lines. On post-operative follow-up all patients showed topographic stability of keratoconus and none of them showed any regression 2 years post-surgery.

Management of patients with keratoconus is complex with various available therapies focusing mainly on topographic stabilization. Providing optimal refractive and vision results to patients with keratoconus still remains challenging to the refractive surgeon. Our results confirm that TICL is a safe and effective long-term surgical option mainly for visual rehabilitation in keratoconus with good predictability. The key to a successful outcome post-TICL implantation is patient selection. It alleviates the need for spectacles or contact lens and thus offers better quality of life to the patients.