HIGH-RESOLUTION WAVEFRONT ANALYSIS IN KERATOCONUS APPLYING NEW ASTROPHYSICS TECHNOLOGY: A CROSS-SECTIONAL STUDY.

To perform optical aberration assessment with a new high-resolution device and applied image analysis techniques to characterize keratoconus.

This study was carried out at the Fundación Jiménez Díaz University Hospital, a tertiary care referral centre with the largest number of corneal transplants performed in the Community of Madrid and the second in Spain

This is a cross-sectional study where 43 eyes from 25 healthy patients and 43 eyes from 27 keratoconus patients were analyzed by a corneal tomography system and a very high resolution (8,6 µm) aberrometer prototype (T-eyede) with a sensor developed originally for the astrophysics field. Corneal aberrations values were provided by tomography device and ocular ones obtained from intensity images captured by T-eyede.  In addition, image processing analysis is performed of the wavefront phase creating a high-pass filter map.

All ocular and corneal optical aberrations were higher in the keratoconus group when compared to control group reaching statistically significant differences (p<0.001). In both groups, ocular aberrations were lower than corneal aberrations (p<0.001), specifically significant was astigmatism and coma aberrations with a reduction of 57% and 51% respectively. Based on the analysis on wavefront phase filtered we noticed two different representations patterns, one smooth and other presented straight/curved bands. Almost the entire control group (95%) showed the first pattern versus 77% of the keratoconus group showed a rough/uneven filtered map (Chi-Square test p<0.001).

Ocular aberrations provided by this device are reliable, precise and are well correlated with the corneal aberrations. Furthermore, the extraordinary high-resolution measurements revealed unprecedented micro alterations in wavefront phase of the keratoconus patients which are dependent on the disease stage.