Peds 1

• 1. Proximity
• 2. Retinal Blur
• 3. Vergence
• 4. Tonic
• Bonus - chromatic abberation is another stimulus. 

Its a psychophysical phenomenon that is just the apparent nearness of the target.

Retinal blur. Its also known as the reflex accommodation.

Convergence accommodation to convergence ratio. Its used to determine the change in accommodation that occurs when the patient converges or relaxes convergence a given amount. Its complicated to measure, thus we dont do it in clinic?

This is also known as tonic accommodation. It is the amount of accommodation always present even at resting state. Known to be 0.50-1.00D.

• 1. Amplitude of Accommodation (Sheard's, Donders)
• 2. Facility of accommodation (Flippers)
• 3. Accommodative response (MEM)

• Advantages - Easy to perform
• Disadvantages - Tends to overestimate AoA. Why? The 20/20 is at 40cm..but when moved to 20cm, it now looks like 20/40...This is RDM!!! Kids will also get confused on the definition of blur!

• This is the most reliable method in clinic. 
• We do  it behind the phoropter with pxs best corrected distance Rx. We do not use the little snellen chart, but the 20/25 or 20/30 line. Remember this MONOCULAR! Start with OD by adding minus lenses until the patient reports blurry (by reading it out loud). Go to OS and do the same thing. Go back and forth until OU completely blurred. Dont forget to take 2.50D out at end for working distance. 

Disadvantage - minification of line may confuse patient..thats why you must have them read it out loud..When they cant anymore, take that as your last lens!

• Maximum Expected = 25-(0.4)(age)
• Average Expected = 18-(0.3)(age)
• Minimum Expected = 15-(0.25)(age)  USE THIS ONE!

This is how efficient can the patient stimulate and relax accommodation. 

We test it by +2.00/-2.00D flippers moncular and binocular!

Monocular flippers check for accommodative anomolies.

• 6 yrs 5.5 +/- 2.5cpm
• 7 yrs 6.5 +/- 2.5cpm
• 8-12 yrs 7 +/- 2.5cpm
• 13-30 yrs  11 +/- 5cpm   Dont do past 30 due to pre presbyopia!

Binocular flippers check for binocular/vergence anomolies

• 6 yrs 3 +/- 2.5cpm
• 7 yrs  3.5 +/- 2.5cpm
• 8-12 yrs  5 +/- 5cpm
• 13-30 yrs 8 +/- 5 cpm
• 30-40 yrs  9 +/- 5cpm

MEM is measuring the accuracy of exerted accommodation measured to a specific point in space (usually 40cm for clinic) 

This is performed at the pxs WD (Harmon distance) OUTSIDE the phoropter in FULL illumination. Place the best corrected distance Rx on patient. Place the special card on your retinoscope and use the loose lenses (+0.25, +0.50) and have them read out loud the words/letters on that card. Dip the lens in front of the OD and only hold it for half a second and SCOPE QUICKLY! Find neutrality and do OS.

• Expected is +0.50 +/- 0.50D Lag
• Lead is measured with minus lenses

• 1. Depth of focus
• 2. AC/A
• 3. Pupil Size
• 4. Target color

BCC, FCC, X-cyl

FALSE

We leave the best corrected distance Rx in the phoropter, becuase it will be overestimated if we use an ADD.

It is a binocular accomodative test! You are also not changing the working distance (the target is stationary), while stimulating and relaxing the accomodative system. 

Negative relative accommodation. 

Its tested with plus lenses until the first sustained blur. It will relax the px's accommodation, thus relaxing vergence. The patient will need to keep the image single, so they will induce Positive fusional vergences.

Positive relative accommodation.

Its tested with minus lenses until the first sustained blur. It will stimulate the px's accommodation, and thus convergence. The patient will need to keep the image single, so they will induce negative fusional vergences.

• NRA = +2.00 +/- 0.50D
• PRA = -2.37 +/- 1.00D

• If you overplus, the NRA will be low and PRA will be high
• If you overminus, the NRA will be high and PRA will be low

Functional problems are those where the patient has poor motor task skills or developmental anomolies.

Opposite to that would be pathological...etc.

• Variable VA at D/N
• Tired when reading
• Fall asleep when reading
• Eyestrain and fatigue when reading
• Headaches around eyes WITHOUT sinusitis
• Miscalling words while reading
• Increased sensitivity to light at near work
• Tendency to hold reading material closer or futher away

• Variable acuity while doing refraction (not a malingerer)
• Pupil variation while taking VAs
• Inconsistance with entering VAs and findings
• Fluctuating pupils while performing retinoscopy
• Inability to obtain reliable and accurate final Rx

• 1. Accommodative insufficency - 84%
• 2. Accommodative infacility - 12%
• 3. Ill-sustained accommodation - 1%

• Blurred vision when seeing from D and switching to N (classic)
• Difficulty copying from board and then to the note book

• The AoA is 2D below the minimum expected (HOFSTETTERS)
• The px will tend to reject minus lenses at near and accept plus
• There will be a high NRA in comparison to PRA
• BCC/MEM will be higher lag
• Flippers will show difficulty with minus and lower cpm

• Ortho, EP, XP...can be anything!
• Most commonly is Exo 

• Toxicity by poisoning
• Cranial surgical trauma - whiplash
• Post cranial surgical trauma
• Viral infections
• Dental cavities
• Malnutrition
• Alcoholism
• Pyschological

Visual therapy (which is the best) which is geared towards stimulating accomodation by emphasizing negative lenses. 

As a secondary target, you want the dynamics (facility) of the target to be more efficient. 

This is not a cure, just a compensation for the problem. 

We can place a near point ADD on a FT design. For computer users, try a PAL. 

For a child with constant wear, give 2 Rxs. One for distance Rx to horse around and another with the bifocal for school work.

The classic one is where the patient has difficulty looking from D to N and also N to D. 

This is problem of the facility and dynamics of accommodation. The px cannot relax or stimulate accmmodation effectively. 

• AoA, BCC, MEM are normal! If AoA is low, then its a combo diagnosis with Accommodative insufficiency. 
• Low NRA and PRA (equally low)
• Flippers will show monocular difficulty with plus and minus (be sure to note that the time it takes to clear is equal from the start of the test)

• Grave's disease
• Cerebral palsy
• Diabetes
• Drugs affecting the CNS (as a rebound effect)

FALSE

Remember your patient cannot accept plus or minus at this moment, so bifocal wont do squat (in terms of management or treatment)

• Visual therapy with emphasis on plus and minus lenses. We want to stimulate and relax accommodation. We also want to create the accurate jump from stimulation to relaxation. 
• The second phase is to perform the jump as fast as possible so the patient can be efficient.

This is a problem of stamina. The patient cannot hold accommodation at that point, where they will tire out quickly.

The classic one is intermittent symptoms when reading..It gets blurry and clear at near!

• Normal AoA - however if you repeat a suspect, it will get progressively lower
• BCC, NRA/PRA, MEM usually normal
• Flippers are most important. Will start out normal with plus and minus, but will get progressively worse over time (more with minus)

There is none! Bifocals will not help!

Visual therapy! We have to emphasize both plus and minus lenses to help stimulate and relax accommodation. However when doing minus lenses, have the patient hold the lens longer than the plus to encourage holding accommodation longer. 

The patients accommodative response is greater than required (like 1D is needed, but px responds with 3D instead)

This is not when a patient has more amplitude according to Hofstetters. This is actually a good thing!

This is basically same thing as accommodative excess. But in terms of definition, it is spastic for an amount of time. They cannot physically relax the accommodation, so they hold the blur for 5-10 minutes, 1 hour...etc. 

The classic one is when the patient has difficulty with distance vision after reading. 

• AoA is normal 
• BCC, NRA, MEM (towards lead) are low.
• PRA can be high and go over 2.50 in relation to NRA
• Flippers has difficulty with plus under monocular, but can carry over to binocular conditions

Remember the patient has difficulty with plus at near!

• Drug Tx with cholinergics
• Digitalis
• Encephalitis
• Syphilis
• Influenza
• Meningitis

Functional problems are very infrequent!

FALSE

It will help as management cant do anything for the patient. VT is the best option!

Remember plus lenses make things worse for this patient. You never want to give a near point ADD. Best option is to go into VT. 

VT will be emphasized with plus lenses to "stimulate" the relaxation of the patient. 

TRUE

Standard of care states that you cycloplege kids with hyperopia and myopia. Especially if you see myopia, you can suspect accommodative excess. 

Psuedomyopia is the phenomenon where the patient has accommodative excess. If the patient is exerting too much accommodation, he is increasing the plus in the system so much that he induces myopia. Since its not "real" its dubbed psuedo. Your refraction may find myopia, but on cycloplegia, you find hyperopia. This is key for the accommodative excess patients!

• Psychological conditions
• Cerebral palsy
• Head trauma
• Encephalitis

• 1. Pupillary miosis
• 2. Psuedomyopia
• 3. Esotropia

When there is a difference of more than 1D between the eyes (from Sheards method)

FALSE

Unequal accommodation is where there is more than 1D difference between the eyes. It is VERY RARE and almost no one has unequal accommodation. Recheck your sheards and refraction with biocular balance!

This is a neurological problem, so send out for a neuro consult ASAP!

• Glaucoma
• Head trauma
• Blunt trauma to the eye
• Unilateral amyblopia
• Pharmacological agents - cholinergics and adrenergics

This is no accommodative response in the effected eye with a mydriatic pupil and EOM involvement. 

• Encephalitis
• Meningitis
• Dengue seasons in PR
• Neurological

• Unilateral - The lesion is peripheral
• Bilateral - The lesion is nuclear

This is accomodative facility testing that takes into account the px AoA. 

• The test distance is 45% amplitude. 
• = 1/(amplitude*0.45), rounded to nearest 0.5cm

Lens power range = 30% amplitude and divided by 2, rounded to the nearest 0.25D

• Example: Px amplitude = 10D
• Distance = 1/(10x0.45) = .222m or 22cm
• Lens range = 10x0.3 = 3D, thus use +/-1.50D

• - Always determine the best distance Rx and give the most plus the patient accepts (dont want them to overacommodate at any moment)
• - Emphasize the lens that causes difficulty

Usually 10-12 sessions

• Ocular motilities - start monocular and then binocular
• Saccades and pursuits for 4-5 sessions
• This is done first because its easy and builds rappore with Dr. 
• At the 4th session, start integrating training

• 1st - increase amplitude - We want a px to do a jump from +2D to -6D (8D jump!) without time
• -starting point is the px NRA and PRA values. NRA never goes above +2.00D

• 2nd - Dynamic training - you want the patient to do the 8D jump in 20cpm by using the metronome at 40bpm. .
• - this is highly unlikely, but shoot for the best

Seldom used techique in VT

This is where there is a stimulus in both eyes, but there is no sensory fusion. Only one eye sees the actual target. 

A jump from -2.00 to +2.00D at 15cpm. This is difficult!

This the phase that trains convergence and divergence responses. 

The last phase is vergence/accomodation flexibility. This allows a clear and single image for both systems. It is done by using plus and minus lenses with vergence training. This will allow more flexibility between both systems.