Abstract
Purpose: :
To evaluate the effect of intravitreal bevacizumab (IVB) on anterior chamber flare in eyes with neovascular glaucoma (NVG) and to assess the relationship between flare meter readings and a simplified classification system used to grade iris neovascularization (NVI).
Methods: :
Anterior chamber flare of 19 eyes with NVG was assessed before and one week after injection of IVB (1.25mg/0.05 ml) with the Kowa FM-500 laser flare meter (Kowa Company, Ltd., Tokyo, Japan). The injection was performed under sterile conditions. Measurements were repeated until 7 acceptable readings ( i.e. a signal-to-noise ratio of < 10%) had been obtained from the study eye; the highest and lowest readings were deleted and the machine calculated the mean laser flare photometry value of the remaining 5 readings. Laser flare photometry values were expressed as photon count per millisecond (phc/ms). Comparative statistics were determined using the Student t-test. P < 0.05 was considered statistically significant. NVI was graded as follows: mild (fine, isolated new vessels requiring high magnification on slit lamp for detection), moderate (easily detectable new vessels at low magnification), severe (new vessels prominent at low magnification ± hyphema).
Results: :
Following IVB injection flare-meter readings decreased in 16 eyes and increased in 3 eyes. Overall mean values dropped from 117.3 phc/ms at baseline to 59.5 phc/ms at one week follow-up; this difference was statistically significant (P=0.029). Mean [range] baseline flare-meter readings were 177.2 phc/ms [21.3-241.5] in the severe group (n=10), 106.9 phc/ms [93.1-120.4] in the moderate group (n=3) and 22.5 phc/ms [4.5-50.4] in the mild group (n=6).At one week follow-up the only eye graded as severe NVI had a reading of 114.3 phc/ms; mean flare-meter readings in eyes with moderate NVI (n=4) and mild NVI (n= 14) were 114.4 phc/ms [82.5-132.6] and 39.9 phc/ms [2.1-92.2] respectively. There was no statistically significant difference between flare meter values of eyes classified as moderate before IVB and those meeting the same criteria after treatment (P=0.604); the same relationship was found in eyes classified as mild before and after treatment (P=0.183).
Conclusions: :
IVB reduces the anterior chamber inflammation in eyes with NVG. There is a good association between anterior chamber flare values measured by laser flare meter and a classification system grading the severity of NVI on the basis of clinical assessment of vessel calibre.
Keywords: neovascularization • inflammation • anterior chamber