NORMAL AC/A RATIO VERGENCE DISORDER

Question 1

define basic exophoria

Answer 1

Tonic vergence low & AC/A ratio normal, thus vergence at near & distance will be low.

Question 2

symptoms of basic exophoria

Answer 2

• Near = convergence insuff.
• Far = divergence excess.
• Uses accommodation to increase use of acc conv.
• Asthenopia // intermittent blur & diplopia with distance & near task.
• Symptoms worsen at the end of the day.

Question 3

signs for basic exophoria

Answer 3

Primary Test:
* CT: XT equal magnitude at distance & near (5-7PD)
* NPC: Redu**ced
* DBI/NBI: normal
* DBO/NBO: reduced
* Vergence Fac: difficulty w/ BO

Secondary Test:
* NRA: low
* PRA: normal
* BAF: reduced, hard w/ + lens
* MAF: normal

Tertiary Test:
* BCC/MEM: plano/lead

Question 4

tx for basic exophoria

Answer 4

Primary – SRx
* Hyperopes : (+) lenses can exacerbate pt’s issue at distance & near - consider partial Rx.

Secondary – SRx + VT
* Very successful –> aimed at increasing convergence ranges with use of BO prisms.

Tertiary – SRx + prism
* BI prism can help, especially if deviation is larger than 30PD.

Question 5

define basic esophoria

Answer 5

Tonic vergence high & AC/A ratio normal, thus there is overconvergence at near & distance.

Question 6

symptoms of basic esophoria

Answer 6

• Near = convergence excess
• Far = divergence insuff.
• Asthenopia / intermittent blur & diplopia at distance & near.
• Symptoms worsen at the end of day.

Question 7

signs of basic esophoria

Answer 7

Primary Test:
* CT: EP equal magnitude at distance & near (5-7PD)
* NPC: Reduced
* DBI/NBI: reduced
* DBO/NBO: normal
* Vergence Fac: difficulty w/ BI

Secondary Test:
* NRA: normal
* PRA: reduced
* BAF: reduced, hard w/ (-) lens
* MAF: normal

Tertiary Test:
* BCC/MEM: plano/lag

Question 8

tx for basic esophoria

Answer 8

Primary – SRx
* Hyperopes : give max accepted plus on cycloplegic.
* Myopes : (-) lenses may make it worse.
* ADD power helps at near but not distance.

Secondary – SRx + prism
* BO prism helps.

Tertiary – SRx + VT
* Needed if pt not hyperope.

Question 9

define fusional vergence dysfunction (FVD)

Answer 9

• Restricted PFV & NFV ranges at both distances.

Question 10

symptoms of FVD

Answer 10

• Asthenopia / HA / intermittent blur at both distance and one.
• Symptoms worsen throughout the day.
• Slow/avoidance of reading.

Question 11

signs of FVD

Answer 11

Primary Test:
* CT: Normal at distance & near
* NPC: Reduced
* DBI/NBI: reduced
* DBO/NBO: reduced
* Vergence Fac: difficulty w/ BO/BI

Secondary Test:
* NRA: low
* PRA: low
* BAF: reduced, hard w/ +/- lenses
* MAF: normal

Tertiary Test:
* BCC/MEM: either
* Intermittent suppression common

Question 12

tx for FVD

Answer 12

Primary – SRx
* Might not have refractive error.
Secondary – SRx + VT
* Very successful

Horizontal prism is NOT recommended b/c the phoria at distance and near are normal.