Pix2pix Networks for Scheimpflug Corneal Tomography Image Generation

Pix2pix Conditional Generative Adversarial Networks for Scheimpflug Camera Color-coded Corneal Tomography Image Generation

Computer-aided medical image analysis has advantages, but requires large amounts of training data, which are scarce and costly to obtain, are subject to privacy concerns, and are often highly imbalanced, with over-representation of common conditions and poor representation of rare conditions. Consequently, some methods have been proposed to generate artificial medical images using generative adversarial networks (GANs). Computer aided diagnosis of keratoconus is an emerging research field that may benefit greatly from medical image synthesis, which can affordably provide an arbitrary number of sufficiently diverse synthetic images that mimic real Pentacam images. A new conditional GAN, the pix2pix cGAN, has not been used in this context to date. Here, investigators will assess the efficacy of a cGAN implementing pix2pix image translation for image synthesis of color-coded Pentacam 4-map refractive displays of clinical and subclinical keratoconus as well as normal corneas.

Study Overview

• Status: Completed
• Conditions: Eye Diseases
• Intervention / Treatment: Diagnostic test: Scheimpflug Camera Corneal Tomography

• Study Type: Observational
• Enrollment (Actual): 923

Contacts and Locations

Study Locations

• Egypt
  • Assiut, Egypt, 71515
    • Faculty of Medicine

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 16 years to 48 years (Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

Refractive surgery candidates with unilateral, bilateral, or forme fruste keratoconus, obtained between July 2014 and March 2019 at private eye center, Assiut, Egypt.

Description

Inclusion Criteria:

• Keratoconus group:

  • Presence of a central protrusion of the cornea with Fleischer ring, Vogt striae, or both by slitlamp examination.
  • irregular cornea determined by distorted keratometry mires and distortion of retinoscopic red reflex or both in addition to the following topographic findings as summarized by Pińero and colleagues :
  • focal steepening located in a zone of protrusion surrounded by concentrically decreasing power zones
  • focal areas with dioptric (D) values >47.0D
  • inferior- superior(I-S) asymmetry measured to be > 1.4 D
  • Angling of the hemimeridians in an asymmetric or broken bowtie pattern with skewing of the steepest radial axis(SRAX) .

Suspicious group:

• Defined as subtle corneal tomographic changes as the aforementioned keratoconus abnormalities in the absence of slit- lamp or visual acuity changes typical of keratoconus (forme fruste keratoconus).

Normal group:

• Refractive surgery candidates
• Refractive error of less than 8.0 D sphere
• Less than 3.0 D of astigmatism
• without clinical, topographic or tomographic signs of keratoconus or suspect keratoconus.

Exclusion Criteria:

• • Systemic disease

  • Other corneal disease such as pellucid marginal degeneration
  • History of trauma
  • Corneal surgery such as corneal cross- linking for progressive keratoconus.

Study Plan

How is the study designed?

Design Details

• Observational Models: Cohort
• Time Perspectives: Retrospective

Number of groups / cohorts

3

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Keratoconus; Those with a clinical diagnosis of keratoconus such as: a) the presence of a central protrusion of the cornea with Fleischer ring, Vogt striae, or both by slitlamp examination.(b) an irregular cornea determined by distorted keratometry mires and distortion of retinoscopic red reflex or both in addition to the following topographic findings as summarized by Pińero and colleagues: focal steepening located in a zone of protrusion surrounded by concentrically decreasing power zones, focal areas with dioptric (D) values >47.0D, inferior- superior(I-S) asymmetry measured to be > 1.4 D or angling of the hemimeridians in an asymmetric or broken bowtie pattern with skewing of the steepest radial axis (SRAX) 2.	Diagnostic test: Scheimpflug Camera Corneal Tomography; Pentacam Sheimpflug system(Pentacam HR, Oculus Optikgeräte GmbH, software V.1.15r4 n7) is used for imaging of the anterior and posterior surfaces of the cornea to obtain corneal tomographic maps.
Subclinical keratoconus; Defined as subtle corneal tomographic changes as the aforementioned keratoconus abnormalities in the absence of slit- lamp or visual acuity changes typical of keratoconus (subclinical keratoconus).	Diagnostic test: Scheimpflug Camera Corneal Tomography; Pentacam Sheimpflug system(Pentacam HR, Oculus Optikgeräte GmbH, software V.1.15r4 n7) is used for imaging of the anterior and posterior surfaces of the cornea to obtain corneal tomographic maps.
Normal; This group comprised refractive surgery candidates and subjects applying for a contact lens fitting with a refractive error of less than 8.0 D sphere with less than 3.0 D of astigmatism and without clinical, topographic or tomographic signs of keratoconus nor suspected keratoconus.	Diagnostic test: Scheimpflug Camera Corneal Tomography; Pentacam Sheimpflug system(Pentacam HR, Oculus Optikgeräte GmbH, software V.1.15r4 n7) is used for imaging of the anterior and posterior surfaces of the cornea to obtain corneal tomographic maps.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Scheimpflug camera color-coded corneal tomography images created by pix2pix conditional adversarial network (pix2pix cGAN)	1 day

Collaborators and Investigators

• Sponsor: Assiut University

Study record dates

Study Major Dates

• Study Start (Actual): August 1, 2020
• Primary Completion (Actual): August 20, 2020
• Study Completion (Actual): October 1, 2020

Study Registration Dates

• First Submitted: October 5, 2020
• First Submitted That Met QC Criteria: October 5, 2020
• First Posted (Actual): October 9, 2020

Study Record Updates

• Last Update Posted (Actual): October 19, 2020
• Last Update Submitted That Met QC Criteria: October 15, 2020
• Last Verified: October 1, 2020

More Information

Terms related to this study

• Keywords: Imaging; Cornea
• Additional Relevant MeSH Terms: Eye Diseases
• Other Study ID Numbers: 17300483

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: No

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No