Abstract
Abstract: :
Purpose: To evaluate the Retinal Nerve Fiber Layer Thickness (RNFLT) in ocular hypertensive, glaucoma suspects and glaucomatous eyes (this two latter with superior arcuate defect assessed respectively by Short Wavelength Automated Perimetry (SWAP) and Standard Automated Perimetry (SAP)) and to correlate RNFLT and visual field defects. Materials & Methods: Three groups of subjects have been selected and included in this study: 18 affected with Ocular Hypertension (OH), 19 affected with suspect Primary Open Angle Glaucoma (suspect POAG) and 17 affected with Primary Open Angle Glaucoma (POAG) respectively with normal visual fields (OH), superior arcuate defect (at least 8 points with P<0.5%) at 24–2 full threshold SWAP (suspect POAG) or 24–2 full threshold SAP (POAG). Control group included 20 healthy volunteers. One eye of each subject has been considered. The perimetric defect in areas 3, 4, 5 and 8, 9, 10 of hemifield test in SAP visual fields of POAG and in SWAP of the other three groups, was calculated by adding up the pattern deviation value of the points included in each area. RNFLT measurements have been performed by Optical Coherence Tomography (OCT3, Zeiss Ophthalmology), program Fast RNFL Thickness (3.4): average RNFLT and RNFLT in four quadrants of 90° and in 12 sectors of 30° (named as clock hours, with temporal=9) have been considered. Results: The average RNFLT (µ) in four groups was (mean+sd): 103+14 (control), 96+17 (OH), 90+19 (suspect POAG) and 65+19 (POAG) (ANOVA p=0.000). Compared with controls (t–test), OH had no significant RNFLT difference; suspect POAG had decreased average RNFLT (p=0.020) and RNFLT of superior (p=0.008), nasal (p= 0.043) and inferior (p=0.029) quadrants. RNFLT of inferior quadrant and of sector 7 was related (linear regression) with SWAP defect in superior hemifield (areas 3+4+5) (r=0.459, p=0.042 and r=0.616, p=0.004), and that of sectors 6 and 7 was related with defect of area 4 (r=0.454, p=0.044 and r=0.705, p=0.000). POAG had reduced RNFLT in inferior, nasal and superior quadrants with respect to all other groups (p=0.000). RNFLT of sectors 6 and 7 was related with defect of areas 3 (r=0.489, p=0.046 and r=0.487, p=0.047). Conclusions: Ocular hypertensive eyes had no reduced RNFLT compared with healthy group. Glaucoma suspects and glaucomatous eyes have decreased RNFLT in inferior quadrant, related to the perimetric defect, but also in quadrants corresponding to areas of undamaged visual field. This data suggest that OCT could detect RNFL changes before that glaucomatous visual field alterations be evident with the actual perimetric techniques. #
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • visual fields