Ray-Tracing Aberrometry In Bilateral Customized Excimer Laser Ablation Combined With Corneal Crosslinking For Progressing Ectasia After Penetrating Keratoplasty

To report visual quality improvement after customized treatment of progressing ectasia after penetrating keratoplasty.

Naval and Veterans Hospital, Athens, Greece, AKTINA Center, Athens, Greece

A 40-year-old female patient diagnosed with keratoconus had undergone penetrating keratoplasty (PKP) in both eyes about 20 years ago. Her vision gradually deteriorated over the last years due to increasing astigmatism. At presentation, both PKP grafts were transparent with an Endothelial Cell Density of 1000 in the right eye(OD) and 1200 cells/mm2 in the left eye(OS). Her Uncorrected Visual Acuity was Counting Fingers(CF) and 0.1 and her Best Spectacle Corrected Visual Acuity (BSCVA) was 0.1 and 0.2 respectively (Decimal Snellen Chart). Topography-measured (TMS-5, Tomey, Japan) corneal astigmatism was 11.25D and 8.50D and Corneal High Order Aberrations, measured with Ray-Tracing Aberrometer(iTrace, USA), were 1.204μ and 0.881μ respectively.

Dual Scheimpflug and Placido corneal topography, optical coherence tomography (OCT) and ray-tracing aberrometry measurements were performed during follow-up.

The patient underwent topography-guided Photorefractive Keratectomy (TG-PRK) combined with corneal crosslinking (CXL). After a prolonged epithelial healing procedure that lasted for about 2 months, her Uncorrected Visual Acuity (UCVA), 6 months after the treatment, improved from CF to 0.5 in OD and from 0.1 to 0.6 in OS. Her BSCVA improved from 0.1 to 0.6 in OD and from 0.2 to 0.7 in OS. Corneal astigmatism dropped from 11.25D to 5.75D in OD and from 8.50D to 2.0D in OS and corneal HOA were also reduced from 1.204μ to 0.552μ and from 0.881μ to 0.554μ respectively.

Ectasia treated with a successful PKP may still progress, with a negative impact on visual acuity and visual quality. Customized treatment with TG-PRK combined with CXL may improve visual quality significantly, securing the cornea at the same time. Ray-tracing Aberrometry depicts visual quality improvement more objectively in such cases.