# O3A 6 Vergence

 crossed disparity when you are fixating on a distant objectnear object will have crossed disparity What is uncrossed disparity? when you are fixating on a near objectdx object will have uncrssed disparity What is a measure of vergence? metre angle how do you calculate metre angle? 1/dx in metresobject at 50cm? need 2 MA Vergence demand formula? pd (cm)X100 / d+2.7 How is gradient AC/A ratio calculated? phoria 1 - phoria 2 / lens 2 - lens 1 exo: add negativeEso: positive What is AC/A? amount that vergence changes for a specific change in accommodation What is the calculated AC/A? change in vergence that results per dioptric change in fixation dxchange due to both accommodation and proximal cues What are the 4 vergence components of the Maddox model? tonicaccom vergproximalfusionalassumes all 4 are additiveignores convergence stimulating accom gradient vs calculated AC/A ratio? gradient measured both at 40cm so proximal vergence is the samecalculated is measured at dx and near so proximal is affection one reading How to calculate CALCULATED AC/A? CHANGE IN VERGENCE / CHANGE IN ACC DEMAND CHANGE IN VERGENCE: Vd - phoria dx + phoria near CHANGE IN ACC: Near - dx What to prescribe: ortho at 6m, 10 eso at 40cm CHANGE IN VERGENCE/CHANGE IN ACC 15 - 0 + 10 / 2.5 - 0 25/2.5= 10:1 +1.00D required plus lens because of eso PRA NRA keeps accomm stableonce vergence runs outuse accomblurs Authorsookylala ID225079 Card SetO3A 6 Vergence Descriptionvergence Updated2013-06-26T11:30:56Z Show Answers