Case Reports

Increased accuracy of high-resolution OCT with placido-based topography against Scheimpflug-based imaging in a patient with marked haze post refractive laser surgery

Case Report Details

First Author: R.Abrishamchi SWITZERLAND

Co Author(s):    H. Abdshahzadeh   E. Torres-Netto   F. Gilardoni   N. Hafezi   F. Hafezi        

Abstract Details

Purpose:

The purpose of this case report is to show the difference in measurements provided by a new AS-OCT device combined with Placido corneal topography (MS-39, CSO) and rotating Scheimpflug camera (Pentacam HR, Oculus Instruments; Sirius, CSO Italia), and describe how the combination of high-resolution optical coherence tomography (OCT) with Placido disk technology may modify the diagnosis and surgical planning in patients with marked postoperative haze following refractive laser surgery.

Setting:

University of Zurich and ELZA Institute, Zürich, Switzerland.

Report of Case:

A patient with bilateral astigmatism was treated with transPRK (transepithelial photorefractive keratectomy) in September 2018. Nine months postoperatively, marked mid-peripheral haze and reduced CDVA were noted. Examination with Scheimpflug imaging devices (Pentacam HR, Oculus Instruments; Sirius, CSO Italia) showed a distinct irregular astigmatism. Accordingly, we planned for a therapeutic approach using a corneal wavefront-guided ablation pattern. However, a preoperative examination using a high-resolution OCT with Placido disk technology (MS-39, CSO Italia) revealed a rather symmetric anterior curvature, indicating that the measurements taken with the Scheimpflug devices were inaccurate because of the light scattering caused by the corneal haze. Thus, instead of a customized transPRK, we rather performed a phototherapeutic keratectomy (PTK) in a first step. Three months after PTK, the haze was eliminated and CDVA returned to normal levels. In a second step, we then performed a corneal wavefront-guided PRK to correct the residual refractive error.

Conclusion/Take Home Message:

Imaging of the anterior segment of the eye has undergone an impressive evolution over the last decade. The introduction of scanning-slit topography first and Scheimpflug technology later has allowed clinicians to obtain new information about their patients. One of the main limitations of Scheimpflug imaging is fact that any type of corneal opacities such as scar or haze may lead to false interpretation of corneal height data. As we can see in this patient with corneal opacity, high-resolution OCT technology with placido-based topography might be superior to Scheimpflug imaging.

Financial Disclosure:

None