LETTER TO EDITOR
|Year : 2005 | Volume
| Issue : 3 | Page : 211-212
Kamal Nagpal, Manish Nagpal
Retina Foundation, Ahmedabad, India
Retina Foundation, Near Shahibag Underbridge, Rajbhavan Road, Ahmedabad - 380 004
|How to cite this article:|
Nagpal K, Nagpal M. Author's reply. Indian J Ophthalmol 2005;53:211-2
We thank Dr Singh and colleagues for the interest in our article and the important aspects raised by them. We would like to present our viewpoint regarding the same.
Development of chorio-retinal anastomosis (CRA) subsequent to Radial optic neurotomy (RON) is believed to assist retinal venous outflow., It has been hypothesised that RON may cause CRA earlier than the natural course of central retinal vein occlusion (CRVO), leading to improvement in retinal circulation before irreversible severe damage to retina. Furthermore, it has been suggested that CRA may develop more frequently in cases with non-ischaemic than in ischaemic CRVO. 
We could not document the formation of such chorioretinal shunt vessels in the post-operative angiograms, in cases which were included in this series. However, in subsequent cases of CRVO, which underwent RON at our centre, we have been able to show CRA formation on post-operative angiography [Figure - 1].
Nomoto et al demonstrated some degree of improvement in retinal circulation after RON, in eyes which developed CRA using indocyanine green videoangiography and image analysis, while most eyes without postoperative CRA did not show improvement in retinal circulation. We have demonstrated statistically significant improvement in postoperative vision and clinical improvement of varying degree in all the cases upon fundus examination, retinal photography and angiography. We have stated that RON procedure, as modified by us may possibly work by a combination of different mechanisms including improved retinal blood flow. Vitrectomy and posterior hyaloid peeling have been shown experimentally to decrease macular oedema. We also utilised passive aspiration of retinal haemorrhages and squeezing effect of mechanical pressure of liquid perfluorocarbon to augment surgical results.
The average duration of symptoms at the time of surgery in our series was 37.88 days (range 15-60 days, median: 34.5, SD:15.19). Seven patients presented with less than 30 days duration. The average vision improvement in this sub-set is 0.2, as compared to 0.1 in all cases, as pointed out. In theory, we do believe that RON, performed at the earliest in the group of patients which meet our selection criteria is very useful in avoiding irreversible retinal damage; however because of small numbers no scientific statement can be made. A future larger, comparative study would help to clarify this matter.
We agree that intravitreal triamcinolone acetonide has been found to decrease the macular oedema and improve best corrected visual acuity in CRVO. However, we have not compared this procedure with RON, therefore we cannot comment.
| References|| |
|1.||Garciia-Arumii J, Boixadera A, Martinez-Castillo V, Castillo R, Dou A, Corcostegui B. Chorioretinal anastomosis after radial optic neurotomy for central retinal vein occlusion. Arch Ophthalmol 2003;121:1385-91. [PUBMED] [FULLTEXT]|
|2.||Friedman SM. Opthociliary venous anastomosis after radial optic neurotomty for central retinal vein occlusion. Ophthalmic Surg Lasers Imaging 2003;34:315-7 [PUBMED] |
|3.||Nomoto H, Shiraga F, Yamaji H, Kageyama M, Takenaka H, Baba T, Tsuchida Y. Evaluation of radial optic neurotomy for central retinal vein occlusion by indocyanine green videoangiography and image analysis. Am J Ophthalmol 2004;138:612-9. [PUBMED] [FULLTEXT]|
[Figure - 1]