Microperimetry as a routine diagnostic test in the follow-up of retinal vein occlusion?
In the follow-up of retinal vein occlusions, a patient’s subjective change in vision frequently cannot be confirmed by objective measurements. Furthermore, contradictory results of OCT and distance visual acuity give the impression that current routine diagnostic tests might not be satisfying for patients with retinal vein occlusions. This prospective case series analyses the value of microperimetry as a routine diagnostic test in the follow-up of patients with retinal vein occlusions during therapy.
In a prospective case series, we tested microperimetry as a functional measure in comparison to distance visual acuity, reading ability, and OCT, on 13 patients treated for central or branch retinal vein occlusions. Treatment consisted of intravitreal bevacizumab injections combined with panretinal laser coagulation in cases of peripheral ischemia. If macular edema persisted, bevacizumab injection was repeated, or instead of this intravitreal triamcinolone or focal laser coagulation was applicated. Follow-up ranged from 6–14 months. An interim analysis was performed for the 6-month follow-up.
In the branch retinal vein occlusion group, the average of the retinal thickness measured by OCT was 502.22 μm (±SD 217.75 μm) at baseline and changed to 396.38 ± 154.38 at the 6-month follow-up (p = 0.121). Mean distance visual acuity stayed similar to the study entrance with 0.41 ± 0.34 at the 6-month follow-up (p = 0.944) Mean reading ability improved to 0.51 ± 0.52 at the 6-month follow-up but was not statistically significant (p = 0.435). The mean light sensitivity of microperimetry improved from baseline to the 6-month follow-up: the 40-points group improved from 8.62 ± 5.69 dB to 10.98 ± 5.42 (p = 0.060) and the 8-points group from 6.27 dB to 9.6 dB (p = 0.07) but missed statistical significance. The sector group showed in contrast to this an improvement from 6.02 ± 5.71 dB to 9 ± 6.07 dB (p = 0.025), which was statistically significant. Changes in the central vein occlusion group were not statistically significant but changes for both groups together showed statistical significance.
In the present case series, microperimetry was more convenient to detect, even the subtle functional changes during the disease course of branch retinal vein occlusions than distance and reading visual acuity. This indicates that microperimetry could be a possible valuable tool in the follow-up of branch retinal vein occlusions.