Final Prep

Expected eye alignment values

Distance: ortho to 2^ xp, ortho vertically ± 0.25

Near: ortho to 6^ xp, ortho vertically ± 0.25

Advanced cover test results

Comitant= magnitude same in all 9 gazes (< 8^ difference) vs incomitant= not the same in all 9 gazes (>/= 8^ difference between gazes)

Mechanically restrictive incomitant deviations

Brown syndrome (SO catches), TED, Duane syndrome (lateral rectus innervated by CNIII/globe retraction), ocular myasthenia (ptosis)

Park’s 3 step test

CT in primary, right/left and tilted right/left gaze, worse gaze= circled, find muscle with all 3

Duane’s Classifications

Maddox rod

Subjective, dissociative eye alignment test, doesn’t distinguish tropia vs phoria, line above dot= use BU prism to correct, L Hyper + visa versa, orient lines opposite intended image, NOT USED LATERALLY B/C NON-ACCOMMODATIVE TARGET, can be performed without correction if induced prism is suspected

W4D

Used with tropias/reduced stereo, will not pick up phoria b/c eyes never truly dissociated, only present in light= shallow suppression, present in dark= intense/deep suppression

Lateral Maddox Rod: line to the right of light

RRUE: red right uncrossed eso, uncrossed diplopia, use BO prism (light on nasal retina of OD< perceived from temporal VF)

Lateral Maddox Rod: line to the left of light

RLCX: red left crossed exo, crossed diplopia, use BI prism to correct (light on temporal retina of OD, perceived from nasal VF)

W4D: 5 dots, red to the left

Crossed diplopia, exotropia, temporal retina projects to nasal VF

W4D: 5 dots, red to the right

Uncrossed diplopia, esotropia, nasal retina projects to temporal VF

Sphygomomanometry

Indirect measure of blood pressure

Ascultatory gap

Temporary absence of sounds between phase 2 and 3 that causes underestimation of systolic pressure

Hypertensive retinopathy

Most common physical manifestation of hypertension, mild-severe, could be predictive of cardiovascular disease/stroke, disk edema common, emergent if systemic/ocular findings present

Hypotension numbers

Systolic < 90, diastolic < 60

Normal BP numbers

Systolic <120, Diastolic <80

Pre-HTN numbers

Systolic= 120-139, diastolic= 80-89

Stage 1 HTN numbers

Systolic= 140-159, diastolic= 90-99, refer within 2 months

Stage 2 HTN numbers

Systolic </= 160, diastolic </= 100, refer within 1 month

Critical high point HTN numbers

Systolic >180, Diastolic > 110, evaluate or refer immediately-within 1 week

BP considerations

Topical phenylephrine can alter BP (especially 10%), use alternatives/nasolacrimal occlusion to reduce systemic absorption

Korotkoff Sounds

Phase 1= systolic, appearance of clear tapping sounds, Phase 5= diastolic 2 (phase 4= diastolic 1/muffling), complete disappearance of sounds

False BP causes

High= cuff too small, arm too low, ascultatory gap measured for diastolic, Low= cuff too large, arm too high, deflating too rapidly, ascultatory gap measured for systolic, automated underestimate

Pt Education BP

Biggest impact on hypertension: weight loss/BMI under 24!!, DASH eating plan, dietary sodium reduction, 30 min/day physical activity, moderate alcohol consumption (1-2/day)

Causes of scissoring

Cataract or keratoconus, increase light slightly or focus on central reflex

Retinoscopy in Phoropter Set Up/Procedure

Set PD, confirm vertex distance, ensure sphere and cyl set to 0, dark room lighting, 20/400 RG E, both eyes unoccluded, confirm right eye cannot see the E but left eye can/check for against in both eyes and fog if needed, find principal meridians, neutralize most positive first, neutralize 2nd meridian with cylinder power, remove working distance, check monocular VAs

Posterior focal line vs anterior focal line

Sphere power, most plus meridian/axis, least plus meridian, cyl= difference between 2

Expected VA

1 VA line lower for each 0.25 D of spherical equivalent +1 line for oblique astigmatism

Impact of ±/cyl lenses

Plus lenses= shift interval of sturm anteriorly/towards the cornea, minus lenses= shift interval of sturm posteriorly/away from the cornea, minus cylinder lenses= impact only ONE focal line (focal line parallel to lens axis, orientation of axis marking on lens= focal line being altered)

Just noticeable difference

Denominator of VA/100, show patient choices that total JND (ex: pt is 20/100, JND= 1.00, show +0.50 and -0.50)

Monocular subjective

1st best sphere (3-4 above ret VA and walk down no lower than 2020, trying to place focal point/COLC on retina), JCC (power search/acceptance/axis refinement/power refinement/axis refinement again if >0.75 DC change, end w power, make sure to compensate sphere, goal= collapse interval of sturm), 2nd best sphere (no lower than 2020)

Focal lines during JCC

Flips will move AFL in one direction, PFL in one direction, and change size (NOT POSITION) of COLC. -0.25 moves focal lines of same orientation POSTERIORLY, +0.25 moves focal lines of same orientation ANTERIORLY

Power acceptance

For every 2 white dots the patient rejects= add -0.25 D sphere compensation to place COLC back on retina

Power Search

Checking to see if cyl power was missed, check at 180, 045, 090, and 135, add -0.25 DC, then red/white dot preferences, don’t add more cyl here, endpoint= power rejected at every meridian or red/same

Axis Refinement

Chase the red, initially 15 degree rotations (exceptions= high cyl), repeat until reversal, bracket to 1 degree >/= 1.50 DC, small cyl= find middle of range

Power refinement

For every 2 white dots patient rejects add -0.25D sphere power to place COLC back on retina, if power refinement changes cyl by more than 0.75 DC you must return to axis refinement

Balance

Purpose= equalize stimulus to accommodate (not to balance VA/response), methods: bi-ocular: dissociated with prism (dissociated blur, red-green/duochrome, goodwin), binocular: eyes fused (vectographic/polarized chart, turville infinity balance), alternate occlusion: eyes dissociated

Dissociated Blur Balance

Monocular VA must be equal (</=3 letter difference), 3 BD OD (top chart), 3 BU OS (bottom chart), add 0.75 OU, 3-4 lines above best VA with M1 (lateral displacement of the chart= exo or exophoria)

• Add +0.25 to better eye, if top or bottom clearer more than 2 times in a row= reevaluate M1

• endpoint= both charts equally blurry, obtain reversal

Red/Green Balance (Duochrome Balance)

Based on chromatic aberration (yellow on COLC, red COLC behind the retina, green COLC= in front (red focuses in front of green by 0.5 D), unequal acuity is acceptable

• 3 BD OD (top chart), 3 BU OS (bottom chart), 0.75 D fog, 3-4 lines above worst M1 VA

• look at upper chart, fog until red clearer, then add minus until equal, obtain reversal, if none= most similar blur

• after OS, compare upper chart red and green to lower chart red and green

Goodwin Balance

Monocular VA must be equal (within 3 letters)

• 3 BD OD (top chart), 3 BU OS (bottom chart)

• Fog 0.25 D, 1 line above M1 VA

• add 0.25 to better eye (0,+), same chart better= remove +0.25 better, add -0.25 to worse eye (-,0), same chart better add +0.25 to better (-,+), same chart better remove -0.25 from worse and add a second +0.25 to better (0,++)