Three-Dimensional Optical Coherence Tomography Imaging For Glaucoma Associated With Boston Keratoprosthesis Type I and II

Abstract

Precis: Three-dimensional (3D) spectral domain optical coherence tomography (OCT) volume scans of the optic nerve head (ONH) and the peripapillary area are useful in the management of glaucoma in patients with a type I or II Boston Keratoprosthesis (KPro). Purpose: The purpose of this study was to report the use of spectral domain OCT in the management of glaucoma in patients with a type I or II Boston KPro. Materials and Methods: This study is an observational case series. Four consecutive patients with KPro implants were referred for glaucoma evaluation. A comprehensive eye examination was performed which included disc photography, visual field testing, and high-density spectral domain OCT volume scans of the ONH and the peripapillary area. 2D and 3D parameters were calculated using custom-designed segmentation algorithms developed for glaucoma management. Results: Spectral domain OCT parameters provided useful information in the diagnosis and management of 4 KPro patients. OCT parameters which can be used in KPro patients included 2D retinal nerve fiber layer (RNFL) thickness, 3D peripapillary RNFL volume, 3D peripapillary retinal thickness and volume, 3D cup volume, and 3D neuroretinal rim thickness and volume. In 3 of 4 cases where the traditional 2D RNFL thickness scan was limited by artifacts, 3D spectral domain OCT volume scans provided useful quantitative objective measurements of the ONH and peripapillary region. Therefore, 3D parameters derived from high-density volume scans as well as radial scans of the ONH can be used to overcome the limitations and artifacts associated with 2D RNFL thickness scans. Conclusions: Spectral domain OCT volume scans offer the possibility to enhance the evaluation of KPro patients with glaucoma by using both 2D and 3D diagnostic parameters that are easily obtained in a clinic setting.

Glaucoma management in patients with penetrating keratoplasty or keratoprosthesis

“…Retinal nerve fiber layer (RNFL) thinning measured using SD-OCT can be indicative of glaucoma progression. In a prospective study of 16 KPro eyes with penetrating keratoplasty eyes as controls, high test-retest reliability and repeatability were observed in SD-OCT RNFL thickness measurements in KPro eyes [30 & ], although another study noted higher rates of segmentation error of the RNFL in KPro eyes [31].…”

Artificial Cornea: Past, Current, and Future Directions

“…Nonpassopon et al gathered information from several Boston KPro clinical trials and found 20.2–40% of eyes had an increase in intraocular pressure (IOP), 14–36% developed de-novo glaucoma, and 13–33% had progression of previously present glaucoma ( 42 ). These results are primarily due to the device being unable to detect elevated IOP early with standard tonometry techniques due to the rigidity of the KPro device ( 68 ). Therefore, a potential solution has been introduced by integrating a micro-optomechanical pressure sensor into the Boston KPro device.…”

“…It was concluded that RPM formation shortened the optical cavity and caused an artificial IOP increase ( 69 ). Another alternative is to use three-dimensional (3D) spectral-domain optical coherence tomography (OCT) to enhance the evaluation of KPro patients with glaucoma ( 68 ).…”

<p>Boston Type 1 Keratoprosthesis: Updated Perspectives</p>

“…85 In addition to better IOP monitoring, several publications advocate the use of anterior segment optical coherence tomography (OCT), 3D-optic nerve OCT, optic nerve head imaging and digital planimetric analysis of Goldman visual field, to better assess structural and functional glaucomatous change after BKPro implantation. 62,63,86 Many modalities are also postulated to prevent other BKPro-related complications. The lack of biointegration has long been considered one of the greatest BKPro downsides leading to a continuous risk of intraocular infection.…”