Accommodation

T

T or F: accommodative and vergence systems are linked- changes to one will affect the other

- zonules of the ciliary body control the amt of lens change creating the accommodative response ( controlled by autonomic system )

how do the lens and zonule play a role in accommodation

Lenses ! - they bft from added plus lenses - also want to Rx the amt for near that puts the pt in a normal lag situation ( want the pt to accommodate 0.50-0.75 less than the stimulus ) > low plus for reading

how do we manage AI and Ill sustained accommodation

VT is the best option - we have to teach them how to relax their accommodation before they can stimulate it ( reset point )

how do we manage Accommodative excess or spasm

VT is the BEST option

how do we manage accom infacility

1. in the distance- the ciliary muscle will be relaxed , causing tension within the zonules and a decrease in the curvature of the lens 2. at near- the ciliary muscles contract , there will be a slack within the zonules, and an increase in curvature of the lens

how does the ciliary muscle change based on looking from distance to near

they are having difficulty stimulating accommodation, thus they are under accommodating for the stimulus. This means they use less accommodative convergence and you will measure a larger amt of XP ( some pts may even show small amts of eso)

how is accomm. insuff related to a pseudo CI ?

they will be using their accommodative convergence system to help supplement the inadequate PFV

if pt has a primary dx of CI, how can that lead to an accommodative excess

accommodation - main sx include asthenopia, HA, watery eye, red eye

this is the ability of the eyes to focus on objects at various distances

accommodative infacility

this is the inability to shift focus efficiently and quickly to different locations in space - slow accommodative dynamics - changes occur with effort and difficulty

accommodative insufficiency

this is when accommodation is lower than expected for the pts age - HALLMARK : reduction of acc amp by 2.00D or more - related to pseudo CI

unequal accommodation

this subcategory of accom insuff is a diff in monocular acc amp by at least 0.50D b/w the eyes - results from head trauama, organic disease, or functional amblyopia

paralysis of accommodation

this subcategory of accom insuff is when acc amp is markedly reduced or absent - results from organic condition or head trauma ( ie glaucoma, diabetes, lead poisoning etc)

reflex accommodation - less than or equal to 2.00D of blur

this type of accommodation is automatic focus of the eye to maintain a clear image - occurs due to retinal blur - larges and MOST important component of accommodation

proximal accommodation

this type of accommodation is caused by knowledge of perceived nearness of the object - 4-10% of total accommodative response

ill sustained accommodation - initially presents like AI but over time they fatigue

this type of accommodation is difficulty maintaining focus on a target as fatigue starts

vergence accommodation

this type of accommodation is induced by the vergence system - second MAJOR component of accommodation

accommodative excess or spasm - theses pts tend to over accommodate , so they will show signs of near esophoria

this type of accommodation is the inability to relax accommodation - can be assoc with esophoria or exophoria

tonic accommodation - mean for young adults is 1.00D range from 0-2.00D - reduces with age

this type of accommodation requires NO stimulus - baseline neural innervation from the midbrain - measure in complete darkness

1. Blurred vision 2. HA 3. eyestrain 4. Pulling sensation 5. Fatigue/sleepiness 6. Loss of comprehension 7. Movement of print 8. avoidance of close work

what are some Sx of Accom Insuff

1. blurred vision when looking far to near or vice versa 2. HA 3. Eyestrain 4. Loss of comprehension over time 5. Reading prob/ avoidance 6. movement of print 7. fatigue 8. pulling sensation around the eye

what are some symptoms of accomodative infacility

1. Amps: Low based on age 2. MEM and FCC: High Lag 3. PRA: Low 4. Facility : trouble clearing minus ( mono. and bino) 5. BO vergence to blur : Low at near * pts have trouble stimulating accommodation and accommodative convergence

what are the signs of Accom insuff

1. Amp: Normal but reduces on repeated testing 2. MEM and FCC: high lag 3. PRA: Low 4. Facility : trouble clearing minus ( reduces on repeated testing ) ( Mono and BIno )

what are the signs of Accomm. INfacility

1. Amp: May appear to be high if low ACA 2. MEM and FCC: Low lag or lead 3. NRA: Low 4. Facility : Difficulty clearing plus ( MOno and Bino) 5. BI vergence to Blur: Low at near

what are the signs of accommodative excess

1. Amp: Normal 2. MEM and FCC : normal 3. NRA/PRA: Low NRA AND PRA 4. Facility : difficulty clearing plus and minus ( Mono and BIno) 5. BO and BI vergence to blur: low at near * these pts have ENOUGH amp they just don't know how to stimulate and relax it

what are the signs of accommodative infacility

1. paralysis of accommodation 2. unequal accommodation

what are the subcategories of accommodative insuff

1. blurred vision worse after reading 2. HA. 3. Eyestrain 4. difficulty focusing from far to near 5. sensitivity to light

what are the sx of accommodative excess

correct the Rx - long standing uncorrected Rx can cause probs to the accommodative and convergence systems - long standing uncorrected myopes under accommodate so they will show low Amps, high lag, and a low PRA - long standing hyperopes are over accommodating and will suffer with accommodative fatigue , low lag, or possibly a lead, a low NRA, and PRA bc they have trouble stimulating and relaxing

what should we do first to manage accommodation

1. first line therapy when RE/ BF are not effective 2. Fix the prob from the source 3. Work on improving flexibility of accommodative system while integrating vergence system

when is VT indicated

1. convergence for SV 2. pupil constriction for depth of focus 3. increase in lens curvature for clear vision

which three things happen during accommodation ( triad )

insufficiency and ill sustained

which two types of accommodation have trouble stimulating their accommodation

accommodative excess

which type of accommodation has trouble relaxing their accommodation

accomm. infacility

which type of accommodation has trouble stimulating and relaxing their accommodation