Abstract
Purpose :
Excessive eye elongation in highly myopic eyes has been suggested to associate with staphyloma formation and scleral changes. The purpose of this study is to determine if subfoveal scleral thickness is associated with axial length using SSOCT images enhanced by adaptive compensation in highly myopic patients with a staphyloma.
Methods :
A prospective imaging study was performed on 27 eyes of 16 highly myopic patients (> 26 mm of axial length) with a clinical diagnosis of staphyloma. IOLMaster axial length and swept source optical coherence tomography (SSOCT, DRI OCT-1, Atlantis, Topcon) were acquired. Scleral boundaries on 12 mm SSOCT line scans through the foveal center became more distinct after enhanced by adaptive compensation using Reflectivity 3.4 software (based on direct application of pixel intensity exponentiation). Subfoveal scleral thickness measurements were made on ImageJ (Bethesda, MD). Univariate regression analysis was used to correlate the subfoveal scleral thickness with axial length.
Results :
Eyes examined had a mean axial length of 30.9 +/- 2.1 mm (mean +/- standard deviation, range 26.6 to 35.5 mm) on IOLMaster and a subfoveal scleral thickness of 291 +/- 79 microns (146 to 508 microns on enhanced SSOCT images). Linear regression demonstrated a significant association between greater axial length and lower scleral thickness (p = 0.03). Specifically, a 1 mm increase in axial length is associated with a 15.5 micron (5.3%) decrease in subfoveal scleral thickness.
Conclusions :
Subfoveal scleral boundaries on SSOCT images of highly myopic eyes were successfully enhanced by adaptive compensation. Staphyloma have been reported to occur more often in extreme cases of high myopia, and scleral thinning may be associated with increased risk for myopic maculopathy. In such eyes, we find that greater axial length is associated with lower scleral thickness. Both axial length and scleral thickness may be useful indicators of which patients may most benefit from future scleral strengthening therapies.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.