Effect of laser spot diameter on the reproducibility of visual field analysis in diabetic patients with upper temporal retinal vein occlusion.
OBJECTIVE
To evaluate the effect of the laser spot diameter on the reproducibility of the visual field analysis in diabetic patients with upper temporal retinal vein occlusion.


METHODS
Thirty-six eyes of 36 consecutive type-2 diabetes mellitus patients with upper temporal retinal vein occlusion who required sectoral retinal photocoagulation (SRP) treatment were enrolled for the study. Patients with a history of previous retinal laser photocoagulation, significant lenticular opacities and those whose perimetric test reliability criteria were low (fixation loss >20% and false-positive or false-negative responses >33%) were excluded from the study. SRP was applied to the upper temporal retinal quadrant. Nineteen eyes received SRP treatment with 500-mum laser spots (group 1) while the rest of the eyes (n = 17) received SRP with 300-microm laser spots (group 2). Patients underwent five consecutive visual field analyses, each on a different day during a 2-week period, both before and 6 weeks after SRP. The Humphrey field analyzer central 30-2 threshold test using SITA Standard strategy was applied for visual field testing.


RESULTS
The mean age of the patients in groups 1 and 2 were 58.6 +/- 6.7 and 59.1 +/- 7.1 years, respectively (p > 0.05). Pre-SRP mean retinal sensitivities of the lower nasal quadrant in groups 1 and 2 were not different statistically (p > 0.05). Post-SRP mean retinal sensitivity of the lower nasal quadrant was significantly higher in group 2 than group 1. Moreover, mean defect has been found to be lower in group 2 (p < 0.05). The coefficient of variation for pre-SRP retinal sensitivity measurements were 7.9 and 7.6% for groups 1 and 2, respectively (p > 0.05). The coefficient of variation for post-SRP retinal sensitivity measurements were 3.8 and 2.1% for groups 1 and 2, respectively (p < 0.05).


CONCLUSIONS
SRP treatment with 300-microm diameter laser spots may yield more reproducible visual field data than that with 500-mum diameter laser spots. Moreover, the improvement in the retinal sensitivity of the patients with branch retinal vein occlusion is more marked in case where 300-microm laser spots are used.
Akar
Yusuf
Y
Department of Ophthalmology, Akdeniz University School of Medicine, Antalya, Turkey. yakar@akdeniz.edu.tr
Apaydin
K Cemil
KC
Metinsoy
Mehmet
M
D000368:Aged; D003930:Diabetic Retinopathy / Q000503:physiopathology* / Q000601:surgery*; D005260:Female; D006801:Humans; D017075:Laser Coagulation / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011184:Postoperative Period; D015203:Reproducibility of Results; D012160:Retina / Q000601:surgery; D012170:Retinal Vein Occlusion / Q000503:physiopathology* / Q000601:surgery*; D013997:Time Factors; D014792:Visual Acuity; D014794:Visual Fields