Analysis of Superficial Deposit Depth in Granular Corneal Dystrophy Type 2 Using Spectral-Domain Optical Coherence Tomography

Abstract

Purpose: The appearance of amyloid and hyaline deposits at various depths in the corneal stroma is well known in cases of granular corneal dystrophy type 2. Although the analysis of deposit depth in the stroma is essential for phototherapeutic keratectomy (PTK), only a few detailed analyses have been reported in the literature. In the present study, we aimed to assess the deposit depth by using spectral-domain optical coherence tomography (SD-OCT) at the anterior eye.

Methods: We included 95 eyes from 51 patients (18 males and 33 females; average age, 67.6 years) in this study. We measured the deposit depth from the surface of cornea in patients with granular corneal dystrophy type 2 and without a history of corneal operation, at Osaka University Hospital from February 2008 to August 2013. Using SD-OCT (RTVue-100; Optovue, Inc.), we analyzed the frequency of protrusion from surface of corneal stroma and the depth from the epithelium to the apex of the hyaline granule deposit in 2 slices, in the horizontal and vertical directions. Furthermore, we compared the deposit depth between patients aged <65 years and those aged ≥65 years.

Results: Protrusion of the deposit from the surface of the corneal stroma was detected in 78.9% of cases (75/95 eyes). The average depth from the surface of the cornea to the apex of the deposit was 30.9 ± 10.8 μm. This average depth was 30.1 μm among the patients aged <65 years (30 eyes) and 31.5 μm among the patients aged ≥65 years; no significant difference was noted in this value between the 2 groups (p = 0.598).

Conclusions: Considering that protrusion of the deposit from the surface of the corneal stroma occurs in approximately 79% of eyes of the patients with granular corneal dystrophy type 2, we recommend that PTK should be carefully performed. Moreover, we did not identify any relationship between aging and the depth from the surface of the cornea to the apex of the deposit.

Keywords: 479 cornea: clinical science • 550 imaging/image analysis: clinical