Fluid reservoir thickness and corneal oedema during closed eye scleral lens wear

To investigate associations between the diurnal variation in a range of corneal parameters, including anterior and posterior corneal topography, and regional corneal thickness. Fifteen subjects had their corneas measured using a rotating Scheimpflug camera (Pentacam) every 3 to 7 h over a 24-h period. Anterior and posterior corneal axial curvature, pachymetry and anterior chamber depth were analyzed. The best fitting corneal sphero-cylinder from the axial curvature, and the average corneal thickness for a series of different corneal regions were calculated. Measures of intraocular pressure and axial length were also taken at each measurement session. Significant diurnal variation was found to occur in both the anterior and posterior corneal curvature and in the regional corneal thickness. Flattening of the anterior corneal best sphere was observed at the early morning measurement upon waking (p < 0.0001). The posterior cornea also underwent a significant steepening (p < 0.0001) and change in astigmatism 90/180 degrees at this time. A significant swelling of the cornea (p < 0.0001) was also evident upon waking. Highly significant associations were found between the diurnal variation in corneal thickness and the changes in corneal curvature. Small but significant diurnal variation occurs in the regional thickness and the shape of the anterior and posterior cornea. The largest changes in the cornea are typically evident upon waking. The regional corneal swelling observed at this time was not uniform, being slightly greater in peripheral corneal regions. The pattern of corneal swelling evident on waking resulted in a steepening of the posterior, and a flattening of the anterior corneal surface.

To examine the diagnostic indications and relative merits of a fluid-ventilated, gas-permeable scleral lens for improving vision impaired by irregular astigmatism and for providing a therapeutic environment for managing severe ocular surface disease. After a review of scleral lens development and a description of current design and manufacturing innovations, indications for fitting the Boston Scleral Lens were evaluated based on a retrospective review of all available records of patients fitted with this device, and outcome experiences were described. A total of 875 eyes of 538 patients were fitted with the fluid-ventilated, gas-permeable scleral lens during the past 18 years. Most patients were fitted in the past 4 years. Indications included managing severe ocular surface disease and rehabilitating vision impaired by irregular astigmatism associated with corneal disorders. Rigid gas-permeable contact lenses either were not tolerated or were contraindicated in all eyes. Outcomes included improved vision and reduced ocular pain and photophobia associated with severe ocular surface disease. Scleral lenses promoted healing of persistent epithelial defect (PED) refractory to other treatments and prevented PED recurrence in stem cell-deficient and neurotrophic corneas. Microbial keratitis occurred in 4 of 22 eyes treated with extended scleral lens wear for PED after penetrating keratoplasty. The fluid-ventilated, gas-permeable scleral lens is an important front-line tool for managing many corneal disorders refractory to other treatment measures or otherwise requiring keratoplasty.

To report treatment of persistent corneal epithelial defects unresponsive to other therapies by extended wear of a fluid-ventilated gas-permeable scleral contact lens.