Assessment of visual function in choroidal neovascularization with scanning laser microperimetry and simultaneous indocyanine green angiography

Background: Clinical management and treatment of diseases with choroidal neovascularization (CNV) are mainly based on visual acuity, which map give an incomplete picture of the associated visual dysfunctions. With the advent of new experimental treatment modalities such as alfa-interferon, radiation, or surgical excision of CNV, it is increasingly important to develop better methods for characterizing the associated visual function. Microperimetry with the scanning laser ophthalmoscope (SLO) allows precise point-to-point correlation between visual function and the macular pathology. However, precise delineation of CNV is a prerequisite for accurate correlation of the functional results with the CNV. Methods: A total of 30 eyes with CNV secondary to age-related macular degeneration were evaluated with static manual microperimetry using the SLO to quantitate relative and absolute scotomata within the CNV. For precise delineation of the CNV, indocyanine green (ICG) angiography was simultaneously performed, allowing stimulus presentation at any desired retinal location under visual feedback of the angiogram. Results: A relative scotoma was detected in 19 and an absolute scotoma in 21 out of 40 eyes. The depth of the scotomata was correlated with the duration of symptoms (P<0.01). Eyes with well-defined CNV had significantly deeper scotomas than eyes with occult CNV (P<0.005). Conclusion: Microperimetry using the SLO and simultaneous ICG angiography demonstrated relative and absolute scotoma within the CNV. The depth of the scotoma map guide the ophthalmologist in selecting the adequate treatment.