Bilateral Keratoconus: a Cataract Preoperative Assessment Incidental Finding. Role of Tomography in Biometry and Multifocality of Cone Effect.

Background: Implantation of intraocular lenses (IOLs) for full refractive correction at all distances is the ideal goal for cataract surgery. A comprehensive examination is pivotal to identify corneal pathology such as keratoconus, in order to achieve optimal outcomes with selection of premium or monofocal IOLs. Case report: A 57-year-old male presented for cataract surgery preoperative assessment. Ophthalmological examination indicated an unremarkable condition, while his files did not report any previous ocular pathology. The patient had high expectations for optimal refractive outcomes without spectacles and therefore, implantation of premium IOLs was considered. Preoperative biometric measurements using IOL Master 700 demonstrated a non-significant anterior corneal astigmatism in both eyes. The central corneal topography maps revealed an asymmetric colour appearance indicative of irregular astigmatism in the right eye, while colour gradation towards higher dioptres was present in the left eye. Despite not being pathognomonic for clinical ectasia, these visually relevant asymmetries warranted further investigation. Additional corneal tomography using Pentacam Scheimpflug imaging revealed an inferior symmetrical well-delineated mild keratoconus. Therefore, the selection of monofocal spherical IOL was decided. The patient had uneventful phacoemulsification bilaterally. At one month postoperatively, his unaided visual acuity at distance was 20/20 in both eyes, he could perform a Jaeger 2 scale for near vision, while subjectively had no complaints of unwanted photic phenomena. Conclusion: Our case highlights that a detailed corneal evaluation may add value to appropriate decision making concerning the selection of IOL implant for optimal visual outcomes. In addition, an enhance depth of focus might be provided postoperatively in selected mild keratoconic cases.