Decoding Cone Morphology in Keratoconus: A Retrospective Study on Contact Lens Selection in Turkish Patients

To explore the relationship between cone morphology and the selection of appropriate contact lens types for patients with keratoconus. Specifically, this study aimed to evaluate how keratometry values, cone morphology, and disease severity influence contact lens fitting and visual outcomes. The goal was to optimize contact lens fitting and improve visual rehabilitation for these patients by understanding the correlation between these parameters.

This retrospective study reviewed data from 108 eyes of 73 patients with keratoconus who had undergone corneal cross-linking and had not undergone any prior refractive surgeries. Patient demographics, keratometry values, corneal topography, and keratoconus morphology were recorded, along with the contact lens types prescribed. Keratoconus was classified morphologically (central/nipple, oval, and globus) and graded according to the Amsler-Krumeich system. Statistical analysis was conducted to examine the relationship between disease characteristics and contact lens selection.

A total of 108 eyes from 73 patients (mean age: 28.19 ± 8.1 years) were included. Cone morphology was classified as central cone (61.1%), oval cone (32.4%), and globus cone (6.4%). Scleral lenses were the most commonly prescribed (50%), particularly in eyes with advanced keratoconus, such as globus keratoconus and Grade 4 disease. Hybrid and rigid gas permeable (RGP) lenses were commonly prescribed for moderate keratoconus, while toric lenses were most often used for mild cases. Visual acuity improved significantly after lens fitting, with best-corrected visual acuity (logMAR) improving from 0.85 ± 0.38 to 0.07 ± 0.12 (P < 0.0001). This improvement highlights the effectiveness of individualized lens fitting in enhancing visual outcomes.

Personalized contact lens selection based on keratometry, cone morphology, and disease severity is crucial for optimizing visual rehabilitation in patients with keratoconus. Scleral lenses are the preferred option for advanced keratoconus, while hybrid and RGP lenses are effective for moderate cases. These findings provide valuable insights for tailoring treatment strategies and improving outcomes in keratoconus management. The study highlights the importance of individualizing lens fitting to achieve better visual outcomes and to guide clinical decisions in the management of keratoconus.