Macular hole formation, progression, and surgical repair: case series of serial optical coherence tomography and time lapse morphing video study.

BACKGROUND: To use a new medium to dynamically visualize serial optical coherence tomography (OCT) scans in order to illustrate and elucidate the pathogenesis of idiopathic macular hole formation, progression, and surgical closure. CASE PRESENTATIONS: Two patients at the onset of symptoms with early stage macular holes and one patient following repair were followed with serial OCTs. Images centered at the fovea and at the same orientation were digitally exported and morphed into an Audiovisual Interleaving (avi) movie format. Morphing videos from serial OCTs allowed the OCTs to be viewed dynamically. The videos supported anterior-posterior vitreofoveal traction as the initial event in macular hole formation. Progression of the macular hole occurred with increased cystic thickening of the fovea without evidence of further vitreofoveal traction. During cyst formation, the macular hole enlarged as the edges of the hole became elevated from the retinal pigment epithelium (RPE) with an increase in subretinal fluid. Surgical repair of a macular hole revealed initial closure of the macular hole with subsequent reabsorption of the sub-retinal fluid and restoration of the foveal contour. CONCLUSIONS: Morphing videos from serial OCTs are a useful tool and helped illustrate and support anterior-posterior vitreofoveal traction with subsequent retinal hydration as the pathogenesis of idiopathic macular holes.

Imaging of the optic disc and retinal nerve fiber layer in acute optic neuritis.

PURPOSE: To demonstrate whether optical coherence tomography (OCT-3) and scanning laser ophthalmoscopy (HRT-2) can be used to measure changes of the optic disc and peripapillary retinal nerve fiber layer (RNFL) in eyes with acute retrobulbar optic neuritis that have no clinically apparent optic disc swelling. To correlate these findings with presentation magnetic resonance imaging (MRI) of the affected optic nerve. METHODS: Eight consecutive patients with acute retrobulbar optic neuritis, who had no prior optic neuritis in either eye, were prospectively investigated at presentation and at between 1 and 3 months with clinical examination, OCT-3, HRT-2. At presentation, MRI of the optic nerves were performed in 7/8 patients. RESULTS: Compared to unaffected eyes, affected eyes without clinically seen optic disc swelling at baseline, there was a non-significant trend to increased thickness in the total RNFL, superior and nasal measurements. Baseline HRT in affected eyes showed smaller mean cup to disc ratio (p=0.003) and a smaller cup area (p=0.002) compared with the unaffected eye. The MRI-demonstrated optic nerve lesion did not correlate with OCT RNFL thickening or HRT decrease of the physiological cup. Follow-up imaging of the affected eyes showed normalization of HRT cup size parameters and OCT RNFL thickness (p<0.04). At follow-up, the temporal RNFL had thinning in 7/8 affected eyes (46.8 mum, p=0.021) compared with fellow unaffected eyes (57.8 mum), which did not change. CONCLUSION: OCT-3 and HRT demonstrate mild RNFL thickening or optic disc swelling in acute optic neuritis, even when swelling is not seen clinically. OCT-3 appears to reveal measurable RNFL thinning in the temporal quadrant after retrobulbar optic neuritis, even though vision improves. RNFL imaging may be useful in future studies of residual injury after optic neuritis.

Redefining the limit of the outer retina in optical coherence tomography scans.

OBJECTIVE: A highly reflective layer seen in retinal optical coherence tomography (OCT) has been believed to correspond to the choriocapillaris (CHC) and retinal pigment epithelium (RPE). On gray-scale scans of OCT-2000, and on Stratus OCT, this layer by the outer retinal limit can be resolved into 2 distinct laminae. We analyzed these 2 laminae in normal and abnormal maculae to infer their anatomic correlate. DESIGN: Retrospective study. METHODS: Analysis of macular OCT scans was performed in 44 patients using OCT-2000, and in 39 patients using Stratus OCT. Thirty of these patients had no ocular disease, and their OCT was normal. The other 53 patients had several macular diseases of different etiologies. Both color and gray-scale images were analyzed. RESULTS: Macular OCT scans showed a double laminae at the level where the retina interfaces the RPE in normal subjects using both OCT-2000 and Stratus OCT. In 2-dimensional scans, this laminar structure appears as a double line. It is best distinguished on the Stratus OCT and gray-scale images of OCT-2000. This double line consisted of a thin inner line and a thicker outer line. Similar analysis in patients with macular pathology showed a discernible double line at the retina/RPE interface in at least part of the scan. However, in patients with macular hole, the area corresponding to the absent retina showed only a single line. The inner line component appeared to follow the contour of the retina. This phenomenon was also seen in eyes with neurosensory detachment secondary to central serous chorioretinopathy and other etiologies. In contrast, in macular pathologies where the outer retina did not lose contiguity with the RPE, such as in lamellar macular hole and in cystoid macular edema, the double line persisted. Software for retinal thickness measurements regularly place the outer limit of the retina at the internal aspect of the inner line, probably underestimating the retinal thickness by about 24 to 34 mum. CONCLUSIONS: A double laminar structure at the outer retina/RPE/CHC interface can be consistently distinguished on commercially available OCT of normal eyes. In eyes with macular pathology, OCT analysis of the inner lamina leads us to conclude it is most likely part of the neurosensory retina and not part of the RPE/CHC complex as previously thought.

Assessment of central corneal thickness using optical coherence tomography.

PURPOSE: To demonstrate the capability of model OCT3 optical coherence tomographer to evaluate central corneal thickness (CCT) in normal human corneas in vivo and compare the results with the those of standard ultrasound (US) pachymetry and Orbscan. SETTING: New York Eye & Ear Infirmary Resident Clinic, New York, New York, USA. METHODS: The CCT in 22 eyes of 11 subjects was determined with the OCT3 (Carl Zeiss Meditec), Orbscan (Bausch & Lomb, Inc.), and US pachymetry (DGH Technology, Inc.). Three central corneal scans of each eye were obtained using the OCT3. First, OCT3 data were processed using the standard OCT software program (OCT3(std)). Second, OCT3 raw data were exported and measurements were repeated using Scion Image for Windows program (OCT3(sci)). The OCT3 and Orbscan results were compared with the mean of 5 US pachymetry measurements in each eye. RESULTS: The OCT3(std), OCT3(sci), and Orbscan CCT measurements showed high correlations with US pachymetry (r=0.981, r=0.984, and r=0.942, respectively; P<.0001). Bland-Altman analysis showed a high level of agreement between US pachymetry and OCT3 techniques but not Orbscan. High repeatability for OCT3(std) (r(2)=0.05) and OCT3(sci) (r(2)=0.01) was also seen. CONCLUSION: Results show the OCT3 is an accurate, noninvasive, and reproducible technique for evaluation of CCT.