When and how to do a grid laser for diabetic macular edema

Francesco Bandello, Paolo Lanzetta, Ugo Menchini

Research output: Contribution to journalArticlepeer-review


Macular edema is a common feature of posterior segment diseases. It is an expression of abnormal permeability in either retinal vessels (inner blood-retinal barrier) or in the retinal pigment epithelium (outer blood-retinal barrier). It occurs in either a diffuse pattern where the macula appears generally thickened or, in more severe cases, as cystoid edema with the typical petaloid appearance. Grid laser treatment may be useful to reduce macular edema. Spots of 100-250 micrometers in diameter are applied to the whole posterior pole, one to two groups apart. The foveal avascular zone remains untouched. In patients treated bilaterally, areas temporal and nasal to the macula must be spared to prevent the development of deep scotomas. The mechanism yielding positive results with the grid technique is still debated. Among the most reliable hypotheses are: Proliferation of pigment epithelial cells, followed by and improved efficiency of the outer blood-retinal barrier; proliferation of endothelial cells in retinal capillaries followed by an improved efficiency of the inner blood-retinal barrier; improvement of the retinochoroidal exchanges, and finally, release by coagulative necrosis of a factor able to improve the efficiency of the blood-retinal barriers. Lasers with long wavelengths, such as krypton red and diode, are the most appropriate ones to perform grid treatment.

Original languageEnglish
Pages (from-to)415-419
Number of pages5
JournalDocumenta Ophthalmologica
Issue number3-4
Publication statusPublished - 1999


  • Diode laser
  • Grid laser treatment
  • Krypton

ASJC Scopus subject areas

  • Ophthalmology


Dive into the research topics of 'When and how to do a grid laser for diabetic macular edema'. Together they form a unique fingerprint.

Cite this