Grid photocoagulation

Recently, intravitreal triamcinolone acetonide has been used clinically to treat retinal vascular disease (Fig. 4). A case report by Jonas and Sofker (32) described a patient with nonproliferative diabetic retinopathy and a six-month history of persistent, diffuse macular edema despite grid photocoagulation. Following one intravitreal injection of triamcinolone acetonide, the visual acuity of this patient improved from 20/200 to 20/50 over a five-month follow-up period. It was also noted that there was marked regression of macular edema on clinical examination. Martidis et al. (33,34) reported on the use of intravitreal triamcinolone for refractory diabetic macular edema. Sixteen eyes with a macular thickness of at least 300 pm despite prior photocoagulation were treated with 4 mg injections of triamcinolone. At three-month follow-up the mean decrease in central retinal thickness was 57.5%, with a visual acuity increase of 2.4 Snellen lines. Those with six-month follow-up demonstrated some recurrence of edema and visual acuity improvement was reduced to 1.3 lines. 

The CYOS demonstrated that the natural history of untreated macular edema is poor in many patients. Additionally, the CYOS showed that grid laser photocoagulation for macular edema does not improve visual acuity compared with the natural history of this disease. Therefore, it is important to explore other avenues for managing this common cause of vision loss. 

The Branch Vein Occlusion Study (BVOS) was conducted, in part, to evaluate grid laser photocoagulation as a treatment for macular edema due to BRVO (Fig. 3) (1). 

The Central Vein Occlusion Study Group. Evaluation of grid pattern photocoagulation for macular edema in central vein occlusion. The Central Vein Occlusion Study Group M Report. Ophthalmology 1995 102 1425-1433. 

---