Scheimpflug and OCT analysis of posterior keratoconus

Alexandra Abdala Figuerola M.D.Alejandro Navas M.D., M.Sc.Arturo Ramirez-Miranda M.D.Erick Hernandez-Bogantes M.D. Andrew Olivo Payne M.D.

Enrique O. Graue-Hernandez M.D., M.Sc.

Department of Cornea and Refractive Surgery Instituto de Oftalmologia

“Fundacion Conde de Valenciana”Mexico City, Mexico

Dr. Ramirez-Miranda and Dr. Navas are consultants for Carl Zeiss Meditec. Dr. Ramirez-Miranda is a speaker of Thea Laboratoires.The remaining authors have no financial or proprietary interest in the materials presented herein.

Introduction

• In 1930, Butler described posterior keratoconus.

• It is a rare non-inflammatory corneal disorder characterized by posterior corneal bulge.

• It is classified in generalized posterior keratoconus and circumscribed posterior keratoconus.

• It can be sporadic or congenital due to a development defect and it is usually unilateral.

Purpose

• To report a case-series of 4 eyes with posterior keratoconus; evaluating corneal Scheimpflug topographic changes and corneal optical coherence tomography (OCT).

Methods

• Descriptive study design

• Three patients diagnosed with posterior keratoconus

• Underwent: Slit-lamp examination, corneal optical coherence tomography and Scheimpflug topography

Case 1• 33-year-old male• Decreased visual acuity on OS

20/70

20/70

OS

OS

Case 2• 45-year-old female • Decreased visual acuity OU

20/300

OD

20/400

OD OS

Case 3• 7-year-old male with corneal opacity on his OS• Both Parents and twin brother with

unremarkable corneas

OS

20/100

Results

• Localized central and paracentral keratoconus was diagnosed in 4 eyes.

• Scheimpflug analysis reported no steepening of the anterior corneal curvature map, instead anterior surface flattening in case 1.

• Case 2 reported an area of anterior corneal steepening corresponding to the posterior bulge

• OCT showed posterior corneal curvature changes

Conclusions

• Posterior keratoconus was initially described as having a normal anterior surface, which has been proven the opposite in topographic modeling

• Scheimpflug technology and OCT can be an excellent and helpful diagnostic tool in order to report posterior curvature changes and anterior surface alterations

1. Mannis MJ, Lightman J, Plotnik RD. Corneal topography of posterior keratoconus. Cornea. 1992 Jul;11(4):351-4.

2. Rao SK, Padmanabhan P. Posterior keratoconus. An expanded classification scheme based on corneal topograghy. Ophthalmology. 1998 Jul;105(7):1206-12