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R.E. Frenkel, J.T. Mucciolo; Comparison of Two Image Acquisition Protocols for Scanning Laser Doppler Flowmetry in Glaucoma Patients . Invest. Ophthalmol. Vis. Sci. 2003;44(13):2152.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: To evaluate the proposed standardized optic nerve rim image acquisition protocol that was developed by consensus at the 2002 ARVO SIG Ocular Circulation and Oximetry meeting for the Heidelberg Retinal Flowmeter. In order to be accepted as the standardized image acquisition protocol it must 1) produce a methodology that gives a high number of analyzed valid pixels and 2) allow different investigators to compare their data and results by measuring equivalent retinal capillary regions. The new protocol (B) was compared to our previous protocol (A) to determine the yield of valid pixels and to see if the new protocol is more advantageous. Methods: Two protocols were compared. In both, each of the 2 images were obtained using an acquisition window of 2.7mm X 0.7 mm (16,384 pixels) over 2 seconds which were analyzed with the Automatic Full Field Perfusion Image Analyzer software (AFFPIA-SLDF v. 3.3). The number of pixels that the program determined were valid (analyzed %), was compared between the two protocols. Protocol A made measurements attempting to simultaneously focus on both the rim and retina 1) across the superior one-half of the entire optic nerve rim (SONR) including nasal retina and 2) inferior one-half of the entire optic nerve rim (IONR) including nasal retina. Protocol B made measurements focusing only on the rim of the 1) the superior one-half of the entire nerve (SONR) including nasal retina and 2) inferior one-half of the entire nerve (IONR) including nasal retina. 40 scans from Protocol A were compared with 40 scans of Protocol B and the number of valid pixels in the optic nerve rims were analyzed. Results: Mean values for Protocol A and Protocol B were: SONR: A 2,072 ± 1192, B 3072 ± 879 (p= .002); IONR: A 2,612 ± 1447, B 3152 ± 1176 (p= .10). Conclusion: Optic nerve rim imaging yielded more valid pixels with Protocol B for both the superior and inferior rim though the difference was only statistically significant for the superior rim. The new protocol that was proposed at the 2002 ARVO SIG is improved over our current protocol and should be adopted because more valid rim pixels are achieved when focusing solely on the rim. In conjunction with our previous method of imaging the superotemporal and inferotemporal retina (ARVO, 2002) this method of measuring the optic nerve rim achieves the greatest number of analyzed valid pixels R.E.P. Frenkel, None; J.T. Mucciolo, None;
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