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Elizabeth Dosch, Carolyn Majcher, Rick Trevino, William E Sponsel, David Juett, Kelsey Price, Adreain Henry; Optical Coherence Tomography Angiography Retinal Vascular Response of Dorzolamide in Healthy Eyes. Invest. Ophthalmol. Vis. Sci. 2018;59(9):2862.
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© ARVO (1962-2015); The Authors (2016-present)
To quantify the short-term effects of macular retinal vasculature following topical dorzolamide administration using OCTA in normal human eyes.
OCTA macular cubes (ZEISS AngioPlex®) and IOPs (iCare®) were performed OU on 30 healthy adults. Dorzolamide 2% was then instilled in one eye. lOP and OCTA were repeated at 30 and 60min. 3 and 6mm superficial capillary plexus (3S, 6S; ILM-IPL), and 3 and 6mm deep capillary plexus (3D, 6D; IPL–OPL) en-face images were analyzed. Unaltered histogram data (0 black-255 white) was used to calculate % pixel proportions (%PP), or sums of pixels within three ranges divided by the total number of pixels. %PP ranges for 3mm images were: background (B) 0-30, small capillary (Cs) 45-70, large capillary (Cl) 71-130. Ranges for 6mm were: B 0-45, Cs 60-90, Cl 91-140. % vessel density (%VD = white/total pixels) was done using ImageJ local thresholding. Paired 2-tailed ttests were used.
Mean age (± SD) was 28.9 ± 6.9yr. 15 subjects were female and 18 study eyes (SEs) were OD. IOP decreased OU at 30min but continued to fall in SEs resulting in asymmetry at 1hr (13.9 ± 3.0 vs 14.8 ± 2.8mmHg, p = 0.02). In SEs, B %PP decreased (3S: -2.0 ± 3.9, p = 0.01; 3D: -2.2 ± 5.4, p = 0.04), while Cs %PP (3S: +0.7 ± 1.6, p = 0.02, 3D: +0.8 ± 2.1, p = 0.04) and Cl PP% (3S: +1.6 ± 3.5, p = 0.03) increased at 30min. In 6S and 6D scans, %PP asymmetry emerged at 30min (6S: B p = 0.03, Cs p = 0.04, Cl p = 0.02; 6D: B p = 0.04, Cs p = 0.04, Cl p = 0.002) with lower B %PPs and greater Cs and Cl %PPs in SEs. Only 3S Cs %PP increase persisted at 1hr. No significant %PP changes occurred in non-SEs. SE 6D and 3D %VD increases approached significance at 30min.
Dorzolamide induced transient, consistent macular OCTA B %PP decrease and Cs %PP, Cl %PP increases suggestive of histogram shifting towards brighter intensity values. This may represent decreased background/increased vascular area and/or vessel brightening and requires further qualification. Further investigations using this new technology should be done to explore whether vascular effects coincide with dorzolamide induced functional improvement in heathy and diseased eyes as previous evidenced (Remky et al. Acta Ophthalmol Scand 2005, Sponsel et al. Am J Ophthalmol 1997).
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.
Example of the 3 pixel proportion ranges for a 3mm superficial capillary plexus en-face OCTA image. Each has been placed on a colored backdrop.
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