Morphologic and functional analysis of the optic nerve in premature and term children with OCT, HRT, and pVEP: a 10-year resurvey.

PURPOSE: Most studies on premature newborns have focused on infants of less than 28 weeks of gestational age (GA) due to their increased risk of developing diseases, such as premature retinopathy. Studies on premature infants born between 28 and 35 weeks GA with normal development are less frequent. The aim of our study was to identify subclinical morphologic or functional defects in these children. METHODS: We evaluated 14 premature newborns at birth (mean gestational age, 33.45 weeks) with a neuro-ophthalmologic examination and patterned visual evoked potentials (pVEP). The same subjects were surveyed when they were young children (mean age, 7.5 ± 0.2 years) using Heidelberg retinal tomography (HRT) and optical coherence tomography (Stratus OCT). The pVEP studies were performed as transient (temporal frequency, 1.96 Hz) and steady-state (7.5-Hz temporal frequency). A complete ophthalmic examination also was performed. The data were compared to those from 15 term newborns who were examined in the same manner (mean age, 9.8 ± 0.3 years). RESULTS: A statistically significant thickening of the macular temporal and inferior nerve fibers was found on OCT in premature newborns. The thickness of the superior and inferior retinal nerve fiber layer (RFNL) also was reduced. A difference also was found in rim area thickness based on HRT. Multiple significant P values were found in the VEP P100 peak time and steady-state amplitudes at the time of birth, but not at the time of morphologic analysis. CONCLUSIONS: Healthy, premature newborns may have morphologic abnormalities of the optic nerve. These abnormalities do not cause visual acuity or functional decreases.

Diagnostic validity of optic disc and retinal nerve fiber layer evaluations in detecting structural changes after optic neuritis.

PURPOSE: To assess the diagnostic validity of morphometric examination of the optic disc and retinal nerve fiber layer (RNFL) thickness to detect permanent structural changes after retrobulbar optic neuritis (ON). DESIGN: Evaluation of a diagnostic test. PARTICIPANTS: Twenty-five patients with a history of retrobulbar ON and 29 disease-free controls. METHODS: The optic discs were evaluated by means of confocal scanning laser ophthalmoscopy (Heidelberg Retinal Tomograph [HRT III]), and RNFL thickness by means of scanning laser polarimetry (GDx), and optical coherence tomography (OCT). Vision function was assessed in all subjects by testing visual acuity, contrast sensitivity, color vision, visual field (VF), and visual evoked potentials (VEPs). Statistical comparisons were made between the affected (ON) and unaffected eyes (non-ON) of the patients with ON, and between these eyes and control eyes (Mann-Whitney test and Wilcoxon's test). Receiver operating characteristic (ROC) curves, and sensitivity and specificity in discriminating ON from control eyes, were calculated for the significant parameters. Correlations between the tests were calculated by means of Spearman's correlation coefficient. MAIN OUTCOME MEASURES: We compared OCT, GDx, HRT, and visual testing results in ON eyes versus control eyes. RESULTS: All of the visual function test parameters and RNFL thickness (GDx and OCT) were significantly different between the ON eyes and both the non-ON and control eyes (P<0.01), and there were significant differences in some GDx parameters between the non-ON and control eyes. There were no significant differences in the HRT parameters. The ROC curves indicated that the greatest diagnostic validity was associated with the GDx nerve fiber indicator (AUC, 0.92; sensitivity, 0.80; specificity, 0.97 using a cutoff point of 20.5 between ON and non-ON eyes), and OCT temporal thickness (AUC, 0.92; sensitivity, 0.72; specificity, 0.95 using a cutoff point of 51.5 microm). CONCLUSIONS: When investigating permanent damage after ON, RNFL thickness is a promising biomarker. The GDx and OCT are reliable, noninvasive, user-friendly devices; both show good diagnostic validity and good correlations with functional tests in discriminating affected from unaffected eyes. Retinal nerve fiber layer thinning in non-ON eyes should be further studied as a possible subclinical indicator of disease.