HIGH AC/A RATIO DISORDERS

Question 1

Define convergence excess

Answer 1

excess convergence at near that leads to a greater EP at near than distance (>8PD).

Question 2

symptoms of convergence excess

Answer 2

• Asthenopia / HA / intermittent blur & diplopia with near task.
• Intermittent diplopia at distance if large EP.
• Symptoms present at the end of the day (eye fatigue later).

Question 3

signs of convergence excess

Answer 3

Primary Test:
* CT: EP greater at near than distance (>8PD)
* NPC: normal
* NFV (NBI): reduced
* NFV (DBI): normal
* PFV (NBO): normal
* PFV (DBO): normal
* Vergence Fac: difficulty w/ BI

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

Tertiary Test:
* BCC/MEM: high lag

Question 4

tx for convergence excess

Answer 4

Primary – SRx + ADD
* Hyperopes: give max accepted plus on cycloplegic.
* Myopes: (-) lenses may make it worse.
* Give lowest amount of ADD power to eliminate symptoms at near.

Secondary – SRx + VT
* Recommended – aimed at increasing divergence ranges at near by training with BI prism & minus lenses.

Tertiary – SRx + prism
* Not really needed unless high EP at distance (BO prism).

Question 5

define divergence excess

Answer 5

excess divergence at distance that leads to greater XP at distance than near (>8PD)

Question 6

symptoms of divergence excess

Answer 6

• Parents/patient complain of eye turn – usually occurs when tired
• Photophobia
• Closing one eye in bright light.

Question 7

signs of divergence excess

Answer 7

Primary Test:
* CT: XP greater at distance than near (>8PD). // can also be IXT.
* NPC: normal
* NFV (NBI): reduced
* NFV (DBI): normal
* PFV (NBO): normal
* PFV (DBO): reduced
* Vergence Fac: difficulty w/ BO

Secondary Test:
* NRA: normal
* PRA: normal
* BAF: normal
* MAF: normal

Tertiary Test:
* BCC/MEM: normal

Question 8

tx for divergence excess?

Answer 8

Primary – SRx
* Hyperopes: (+) lenses make XP worse – partial Rx.
* Myopes: (-) lenses may improve XP – full Rx. .

Secondary – SRx + VT
* aimed at decreasing divergence ranges at distance w/ use of BO prism & plus lenses.

Tertiary – SRx + prism
* May help if not suppressing.

surgery acceptable for cosmesis & if deviation >30-35PD (IXT) – success rate 65% – must do VT after.

Question 9

vertical phoria symptoms?

Answer 9

• Blurred vision / HA / asthenopia
• **Diplopia (vertical) **
• Head tilt – towards deviation
• Loses place when reading, jumps lines.

Question 10

signs of vertical disorder

Answer 10

Primary Test:
* CT: vertical deviation
* NFV (NBI/DBI): reduced
* PFV (NBO/DBO): reduced
* Head tilt

Question 11

tx for vertical disorder

Answer 11

Primary – SRx
* Full or partial Rx.

Secondary – SRx + prism
* Full prism – BD over hyper eye & BU over hypo eye.
* Highly successful

Tertiary – SRx + VT
* Work on horizontal b/c it may improve vertical.

Vertical phoria >10PD are good candidates for surgery.