A Quartet Of Methods For Regularising The Irregular Cornea In Keratoconus

Keratoconus is a bilateral, asymmetric ocular disease, characterised by progressive thinning and ectasia of the cornea, leading to significant corneal irregularity[i]. Therefore, satisfactory visual acuity (VA) can be difficult to achieve in patients with keratoconus. In our service, a variety of treatment approaches, and combinations of treatment approaches, are utilised to regularise the cornea. This paper aims to highlight the range of modalities that can be used in the management of keratoconus.

[i] Asimellis G, Kaufman EJ. Keratoconus. 2024 Apr 12. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan–. PMID: 29262160.

Wellington Eye Clinic is a specialised cataract and refractive centre in Dublin, Ireland.

In this paper, we present four different methods currently employed in our service to improve corneal irregularity in patients with keratoconus: Myoring; Femtosecond-Laser assisted Astigmatic Keratotomy with Trans-epithelial topography-guided PRK; CAIRS with KeraNatural; and Conductive Keratoplasty. For each method, we describe the procedure and present the case of a patient treated for keratoconus with this modality in our service. We discuss the background history, along with the patient and technical factors influencing the choice of treatment method. Pre- and post-operative corneal topography for each patient is displayed. We also describe the adjunctive use of TE-PTK/PRK to refine the refractive outcome of all four approaches.

24y/o man treated with bilateral Myoring insertion. Pre-op refraction: 6/60 -1.75/-6.00x95 6/19. Myoring achieved a BCVA of 6/15. Interval TE-PTK performed to a final visual outcome of 6/9.

37y/o man treated with Femtosecond-Laser assisted Astigmatic Keratotomy to reduce astigmatism following penetrating keratoplasty. Pre-op refraction: 6/15 +1.00/-5.00x135 6/7.5. Post-op refraction: 6/12 -0.25/-0.75x40 6/12 & further TE-PRK planned.

35y/o man, pre-op refraction of 6/20 -3.25/-2.50x85 6/20, treated with CAIRS. Post-op refraction: 6/15 +3.5/-3.00x117 6/8.

49y/o man with a history of inferior INTAC extrusion underwent conductive keratoplasty. Pre-op refraction: 6/20 +0.25/-5.25x90 6/7.5. Post-op refraction: 6/9 Plano/-1.75x75 6/7.5.

Keratoconus is a complex corneal disease that can have a significant impact on quality of vision. Therefore, appropriate intervention is required to achieve the best visual outcome for our patients. The choice of approach is made on a shared-decision making basis, taking into account individual patient factors and preferences. In our clinic, TE-PTK/PRK is an important additional modality used to refine the refractive outcome and further capitalise on the debulking of the gross corneal irregularities that the other procedures have achieved.