The use of scanning laser ophthalmoscope microperimetry to detect visual impairment caused by macular photocoagulation

Abstract

Background and objective: To demonstrate the effectiveness of scanning laser ophthalmoscope (SLO) microperimetry in detecting retinal sensitivity and in describing areas of unstable fixation following photocoagulation therapy.

Patients and methods: Two patients with iatrogenic vision loss resulting from photocoagulation therapy underwent a fundus examination, SLO microperimetry, and fluorescein angiography. One patient also underwent indocyanine green angiography.

Results: Two types of visual acuity decrease--sudden-onset and late-onset--were demonstrated following macular photocoagulation, the former resulting from incorrect identification of the fixation point, and the latter from enlarging photocoagulation scars placed in close proximity to the fovea. In one case, SLO microperimetry detected dense scotoma corresponding to the patient's symptoms and an unstable fixation point. In the other case, different retinal sensitivities were found in the photocoagulation scars. No differences were found with fluorescein angiography or indocyanine green angiography.

Conclusion: SLO microperimetry might be effective for quantitative assessment of retinal sensitivity in photocoagulation scars and for detecting fixation points and determining their stability.