Scleral Thickness in Human Eyes

Abstract

PurposeTo obtain information about scleral thickness in different ocular regions and its associations.MethodsThe histomorphometric study included 238 human globes which had been enucleated because of choroidal melanomas or due to secondary angle-closure glaucoma. Using light microscopy, anterior-posterior pupil-optic nerve sections were measured.ResultsIn the non-axially elongated group (axial length ≤26 mm), scleral thickness decreased from the limbus (0.50±0.11 mm) to the ora serrata (0.43±0.14 mm) and the equator (0.42±0.15 mm), and then increased to the midpoint between posterior pole and equator (0.65±0.15 mm) and to the posterior pole (0.94±0.18 mm), from where it decreased to the peri-optic nerve region (0.86±0.21 mm) and finally the peripapillary scleral flange (0.39±0.09 mm). Scleral thickness was significantly lower in the axially elongated group (axial length >26 mm) than in the non-axially elongated group for measurements taken at and posterior to the equator. Scleral thickness measurements of the posterior pole and of the peripapillary scleral flange were correlated with lamina cribrosa thickness measurements. Scleral thickness measurements at any location of examination were not significantly (all P>0.10) correlated with corneal thickness measurements. Scleral thickness was statistically independent of age, gender and presence of glaucoma.ConclusionsIn non-axially elongated eyes, the sclera was thickest at the posterior pole, followed by the peri-optic nerve region, the midpoint between posterior pole and equator, the limbus, the ora serrata, the equator and finally the peripapillary scleral flange. In axially elongated eyes, scleral thinning occurred at and posterior to the equator, being more marked closer to the posterior pole and the longer the axial length was. Within the anterior and posterior segment respectively, scleral thickness measurements were correlated with each other. Posterior scleral thickness was correlated with lamina cribrosa thickness. Scleral thickness measurements at any location of examination were not significantly correlated with corneal thickness or with age, gender and presence of absolute secondary angler-closure glaucoma.

The contribution of glycosaminoglycans to the mechanical behaviour of the posterior human sclera

“…The human scleral thicknesses in this investigation were comparable to those reported in other studies [68,69].…”

Is Choroidal or Scleral Thickness Related to Myopic Macular Degeneration?

“…[19][20][21][22] Except for Shen et al, 20 who studied CT in postmortem eyes and therefore unlikely to reflect choroidal vascularity, none of these studies examined ST and CT concurrently. Subfoveal ST varied depending on the method of measurement: mean subfoveal ST ranged from 281 to 335 lm on OCT 23,24 and 602 to 670 lm in histological studies.…”

“…Subfoveal ST varied depending on the method of measurement: mean subfoveal ST ranged from 281 to 335 lm on OCT 23,24 and 602 to 670 lm in histological studies. 20,22 Scleral thickness may be underestimated when measured with OCT because the posterior scleral border may not be visible in eyes with thicker sclera. Park et al 25 recently compared enhanced depth imaging spectral-domain optical coherence tomography (EDI-OCT) with SSOCT and found a better detection rate for the posterior scleral border with SSOCT (31% vs. 53%, P ¼ 0.008).…”

Optical Coherence Tomographic Imaging of Posterior Episclera and Tenon's Capsule

“…However, histomorphometric examinations of markedly elongated eyes revealed similar thickness values as low as 0.1 mm for the posterior sclera. 10,11 Furthermore, it needs to be taken into consideration that histologic specimens undergo postmortem tissue swelling and tissue shrinkage due to the histologic processing. Sixth, if both eyes fulfilled the inclusion criteria, both eyes of the participant were included into our analysis.…”