Session Title: Imaging I
Session Date/Time: Thursday 26/09/2013 | 08:30-10:30
Paper Time: 09:10
Venue: Hall 3 (Level 0)
First Author: P.Stanga UK
Co Author(s): S. Caputo A. Sala-Puigdollers S. Biswas S. Charles
To image in-vivo the posterior cortical vitreous, the Bursa Premacularis (BPM) and Space of Martegiani (SM), and to measure the BPM using a new 1,050nm Swept-Source optical coherence tomography (OCT) scanner (Topcon® Deep Range Imaging, DRI-OCT1 Atlantis®).
Pilot and retrospective cross-sectional study. One-Hundred nineteen (119) consecutive patients underwent DRI-OCT1 Atlantis® scans. Using a 5-line cross pattern centred on the fovea, the presence or absence of a BPM and/or SM and the stage of posterior vitreous detachment (PVD) was determined in each eye. PVD was classified as: Stage 0: cortical vitreous fully attached to posterior pole throughout the area scanned; Stage 1: perifoveal PVD limited to either the temporal or nasal side of the fovea; Stage 2: perifoveal PVD involving both the temporal and nasal side of the fovea; Stage 3: vitreoretinal separation apart from a vitreopapillary adhesion; Stage 4: complete vitreoretinal separation in the posterior pole throughout the area scanned; Stage 5: vitreoretinal separation not gradable. Single-Line 12mm long horizontal scans passing through the fovea and optic disc were used for measurement purposes; the horizontal (width) dimension of the BPM, and its anteroposterior (depth) dimension at the deepest foveal point, were recorded.
A BPM was imaged in 57.1% (136/238) of eyes (age range 5-100 years). The BPM and SM coexisted in 55.8% (133) of eyes. In 3 eyes the cortical vitreous was completely attached to the surface of the optic nerve. The BPM was present unilaterally in 23.4% (18) and bilaterally in 76.6% (59) of patients. The distribution of PVD in the 238 eyes was 47%, 1.7%, 9.7%, 10.5%, 5% and 25.6% in stages 0 to 5 respectively. Prevalence of BPM was 84.3% (118/140 eyes) in PVD stages 0,1 and 2 combined; 52% (13/25 eyes) in stage 3 and 25% (3/12 eyes) in stage 4. BPM was detected in 4.9% (3/61) of eyes with a non-gradable PVD. Width and depth of the BPM was measured in 94/136 eyes. Mean width was 7,001µ (range: 10,316 – 3,354µ, SD:1412µ) and mean depth was 416µ (range:1,189-31µ, SD:187µ). Width and depth of the BPM did not correlate with age (R2Width=0.0316; R2Depth=0.0108). Bilateral BPM tended to be symmetrical in width but less so in depth (R2Width=0.63 p<0.001; R2Depth=0.33 p<0.001).
The utilisation of Swept-Source OCT with 1,050nm wavelength, 100,000 A-line scans/sec and 12mm long scans enables improved in-vivo anatomical characterisation of the posterior vitreous, measurement of BPM dimensions and assessment of the degree of PVD over the posterior pole. We confirmed the constant co-existence of the BPM and SM. The BPM and SM were absent bilaterally in approximately 10% of patients and unilaterally in 10% of eyes with no PVD or with PVD restricted to the perifoveal region. This finding suggests that the presence or absence of BPM and SM is an indicator of the extent of embryological involution of both primary and secondary vitreous structures. The BPM and SM can be imaged in 15% of eyes in patients in their ninth and tenth decade provided there is no PVD.