Purpose:
To assess visual field characteristics and retinal nerve fiber layer (RNFL) thickness in patients with Boston Keratoprothesis (KPro) for detection of glaucoma using Humphrey Visual Field (HVF), Goldmann Visual Field (GVF), and Stratus optical coherence tomography (OCT).
Methods:
A cohort study of eight eyes of seven patients with Boston KPro (five glaucomatous and three non-glaucomatous eyes) and twenty eyes of twenty normal patients without history of glaucoma was performed. Patients were classified as glaucomatous if they had previously been diagnosed with glaucoma, had history of glaucoma surgery, or were taking glaucoma medications during the time of testing. Central static testing using program 24-2 sita-standard on the Humphrey Field Analyzer, peripheral kinetic testing using isopters I4e, II4e, and V4e on the Goldmann perimeter, and RNFL thickness measurements at the optic nerve head with Stratus OCT were performed. GVFs were scanned into Photoshop and the number of pixels was calculated to determine the area of the isopters.
Results:
GVF Isopters I4e , II4e, and V4e in glaucomatous and non-glaucomatous KPro eyes were significantly more constricted when compared to normal eyes. Only isopter I4e was significantly different between glaucomatous and non-glaucomatous KPro eyes. The foveal threshold and mean deviation on HVF were significantly higher for normals than KPro patients or the KPro subgroups, but there was no difference between the glaucomatous and non-glaucomatous KPro patients. RNFL thickness was similar between normal eyes and non-glaucomatous KPro eyes, but was significantly lower in glaucomatous KPro eyes (see Table 1).
Conclusions:
Glaucomatous KPro eyes had significantly thinner RNFL at the optic nerve head when compared to non-glaucomatous KPro and normal eyes, while RNFL thickness was similar between non-glaucomatous KPro eyes and normal eyes. There is a significant constriction of the peripheral visual field and decreased foveal threshold in KPro patients with or without glaucoma when compared to normal patients.
Keywords: keratoprostheses • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • visual fields