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| LETTER TO EDITOR |
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| Year : 2003 | Volume
: 51
| Issue : 3 | Page : 286-287 |
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Trypan Blue Enhanced Vitrectomy in Clear Gel Vitrectomy
Arvind Kumar Dubey
Correspondence Address:
Arvind Kumar Dubey
 Source of Support: None, Conflict of Interest: None  | Check |
PMID: 14601866 
How to cite this article:
Dubey AK. Trypan Blue Enhanced Vitrectomy in Clear Gel Vitrectomy. Indian J Ophthalmol 2003;51:286-7 |
Dear Editor,
We have read with interest the letter from Dr. Lalit Verma et al published in the journal ( Indian J Ophthalmol 2003;51:106).
We agree that visualisation of clear vitreous for cutting the vitreous base and more so while inducing posterior vitreous detachment is difficult. Clear transparent vitreous while attached to retina is not seen very clearly even by experienced surgeons. Removal of the base of the vitreous is important in conditions with proliferative pathology, however, often the base of vitreous is bloodstained in these cases. Total posterior vitreous detachment is crucial for success of surgery in conditions like idiopathic macular hole and in these cases no contrast is available.
We have tried trypan blue, ICG and NaF1 for the purpose of inducing contrast and have observed the merits and disadvantages of each. Over the last 4 years we have been using Triamcinolone acetomide for inducing contrast to visualise clear vitreous both for base shaving and posterior vitreous detachment.
Trypan blue does produce a contrast but the colour is only faint blue and is more apparent over the base of vitreous and not significant over the posterior cortical vitreous as the dye stains the retinal surface, i.e., the internal limiting membrane also. Furthermore, trypan blue reduces the amount of reflected light and thus any advantage of contrast visualisation is accompanied by reduced illumination. We agree that the dye stains the posterior capsule of the crystalline lens but it also stains the anterior hyloid, making the distinction between the two difficult and in fact increasing the chances of injury to the crystalline lens. Moreover, the whole staining effect from the vitreous gets diluted with time as the infusion is kept open. We differ with the authors that the posterior capsule staining disappears very soon; as a matter of fact this staining lasts longer on the capsule than in the vitreous.
ICG is more effective in giving contrast but since it stains the internal limiting membrane of the retina immediately it does not offer a great advantage for the purpose of inducing PVD, however it works well for purpose of vitreous base visualisation. The cost of this dye prohibits its regular use.
NaF1 has been tried by us and we find it makes sense to use it for vitreous base visualisation. However, it has the same problem for inducing PVD as ICG.
All the three dyes not only stain the formed vitreous but also stain the liquid vitreous and any infusion fluid inside the eye and thus provide no distinction between vitreous gel and vitreous sol, which actually matters.
Triamcinolone suspension is available in concentrations of 10 mg/ml and 40 mg/ml. A dose of 2 to 4 mg in the cavity of eye ball including vitrecto-mised eyes is considered safe. The suspension has a unique feature - the suspended particles adsorb (surface adsorbtion) on formed vitreous and float freely in vitreous sol and infusion fluid, so the free floating particles egress out of the eye with infusion fluid. The particles adherent to formed vitreous give an excellent white contrast against the pink of the fundus and as the reflected light increases the visibility is better even at the same level of illumination. The posterior vitreous detachment induced with this contrast aid is actually seen. We have also observed that with passive suction alone PVD can be induced provided posterior cortical vitreous is clearly visible. The same contrast is seen over the vitreous base and the particles persist to adhere to formed vitreous all through till the vitreous is cut and removed, thus offering a great advantage in vitreous base removal. We have tried this technique to check stage III macular holes after inducing PVD by routine methods and also in stage IV cases, where there is total PVD. We found a thin layer of cortical vitreous still attached to the retina visualised by this technique. This indicates vitreoschisis and not total PVD.
We consider that among all the options available for contrast visualisation of clear vitreous, injection of triamcinolone is most effective. Additionally it can also be used to verify whether a total PVD has really been induced.
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