- Central Retinal Vein Occlusion
- Lucentis and CRVO
Central Retinal Vein Occlusion
The inner layers of the retina receive their blood supply from the central retinal artery. The blood returns to the heart through the central retinal vein. Both vessels enter the eye through a small opening in the middle of the optic nerve. Either because this opening shrinks or because the artery hardens or because of circulations problems, the central retinal vein can become partially or completely occluded.
When a patient develops a central retinal vein occlusion (CRVO), they lose some or most of their central vision. The photographs of the retina on the right are of an eye with 20/50 visual acuity with a central retinal vein occlusion for 6 weeks. The retinal veins dilate and their are retinal hemorrhages. Patients often develop swelling of the central retina-cystoid macular edema--causing some of the vision loss.
Without treatments, 25% of eyes improve, 50% stabilize, and 25% worsen. No treatment has been proven to improve these numbers. At the time of this writing, many retina specialists treat eyes with cystoid macular edema with injections of either Kenalog, Avastin, or Lucentis. All of these drugs can make the retina swelling subside and often the visual acuity improves. Unfortunately, the treatments rarely have a lasting affect. With repeated treatments, some patients have benefit, but some do not.
The below image shows an optical coherence tomography scan of a young woman with a central retinal vein occlusion whose vision improved from 20/200 to 20/60 one month after receiving an intravitreal injection with triamcinolone. The above scan shows the retinal swelling before the injection, the below scan shows a normal retinal thickness after injection.
The below scan shows the before and after optical coherence tomography scans of an elderly man who was treated with intravitreal avastin for macular edema and a central retinal vein occlusion. He had glaucoma and could not be safely treated with intravitreal triamcinolone like the above patient. Intravitreal triamcinolone can cause the intraocular pressure to rise. This man was injected with avastin. He had six treatments prior to the one shown below. His visual acuity initially improved to 20/60 with treatments from 20/200. He had less improvements though with subsequent treatments. The below slide shows his last treatment. Despite the striking improvement in retinal anatomy, he did not notice a visual improvement. His fellow eye is good and that may have kept him from noticing a small improvement in this eye with the central retinal vein occlusion.
Surgical treatment of CRVO is employed by some retina specialists. This treatment has become less popular lately, as the benefits of the treatment may not outweigh the risks.
Laser treatment of CRVO to treat the macular edema or to try to create an alternative circulation, a chorio-retinal anastomosis, can be helpful in select cases.
Monthly examinations of pateints with CRVO for less than six months are very important. Some patients with CRVO and very bad circulation, develop a severe type of glaucoma. In this situation, the eye becomes red and painful and without treatment, total visual loss can occur rapidly. If an examining doctor sees early signs that this complication may occur, then laser treatment can sometimes protect the eye. Once the pressure rise occurs, surgery can be helpful.
48% of LUCENTIS patients gained ≥15 letters at month 6:
- On average, patients treated with LUCENTIS experienced VA gains throughout 6 months of treatment
- 1.5% of patients lost ≥15 letters with monthly LUCENTIS at 6 months versus 15.4% with sham
Brown DM, Campochiaro PA, Singh RP, et al; for the CRUISE Investigators. Ranibizumab for macular edema after central retinal vein occlusion: six-month primary end point results of a phase III study. Ophthalmology. 2010;117:1124-1133.