Comparative evaluation of optical coherence tomography in glaucomatous, ocular hypertensive and normal eyes

To correlate the findings of optical coherence tomography (OCT) evaluation of retinal nerve fiber layer (RNFL) thickness with visual field changes in glaucomatous, ocular hypertensive and normal eyes.

Thirty consecutive normal, 30 consecutive ocular hypertensive and 30 consecutive glaucomatous eyes underwent a complete ophthalmic examination, including applanation tonometry, disc evaluation, (30-2) Humphrey field analyzer white on white (W/W) perimetry and short- wavelength automated perimetry. Thickness of the RNFL around the optic disc was determined with 3.4 mm diameter-wide OCT scans. Average and segmental RNFL thickness values were compared among all groups. A correlation was sought between global indices of perimetry and RNFL thickness.

Of the 90 eyes enrolled (mean age of patients 52.32+/-10.11 years), the mean RNFL thickness was significantly less in ocular hypertensive (82.87+/-17.21 mm; P =0.008 and glaucomatous eyes (52.95+/-31.10 microm; P < 0.001), than in normals (94.26+/-12.36 microm). The RNFL was significantly thinner inferiorly in glaucomatous eyes (64.41+/-43.68 microm; P<0.001). than in normals (120.15+/-14.32 microm) and ocular hypertensives (107.87+/-25.79 microm; P<0.001). Ocular hypertensives had thinner RNFL in the nasal, inferior and temporal quadrants (P<0.001) when compared to normals. Global indices in ocular hypertensives on SWAP showed Mean Deviation (MD) of 5.32+/-4.49, Pattern Standard Deviation (PSD) 3.83+/-1.59 and Corrected Pattern Standard Deviation (CPSD) 2.84+/-1.85. The RNFL thickness could not be significantly correlated with global indices of visual fields in ocular hypertensives.

Optical coherence tomography is capable of detecting changes at the level of RNFL in ocular hypertensive eyes with normal appearance of discs and W/W perimetry fields.