Features and tx for constant XT?
- basic exo, uni, rare, AC, early onset
- poor prognosis for functional cure - tx difficult
Intermittent XT- convergence insuf/basic XT?
- sx, 25PD
- good sensory fusion with stereo
- vt and prism tx good w/o surgery
intermittent XT- diverg excess?
- exo/stereo near, suppression in dx
- tx: build on fusion they have
- since nystagmus- penalisation with atropine
- surgery as early as possible
- prog poor for full functional cure even with surgery
Accom acquired ST features?
- angle varies with accom
- >2D hyp
accom acquired ST tx?
- daytime emergency - treat right away otherwise may become partially accom (nonaccom component on top) intermittent->constant
- 1. full rx + add will usually eliminate strab- eyes straight-image hitting both foveas-eliminate suppression
- 2. amb therapy is necessary
- 3. sensory fusion: increase fusion ranges and stereo
- 4. no fusion: anti suppression tx
Partial accom acquired ST?
- >2D hyp
- AC ef-rare, reduced stereo
- uni- amblyopia
- 12-18M of VT usually required
Non accom acquired ST?
- poor prog w/o surgery
- onset >2YO + fusion, post surgery fusion chance
Post surgery with acquired ST?
- poor prog with VT, prism, lenses
- scarring, fibrosis, limitation of gaze
- no stereo
What are the 6 phases of tx?
- 1. establish initial optical correction
- 2. improve MV functioning
- 3. establish normal peripheral fusion
- 4. establish normal central fusion
- 5. obtain bv in free space
- 6. Maintenance program
steps in establishing an initial optical correction?
- 1. optimum lenses
- 2. prism
- 3. occlusion therapy
Optimum lenses goals?
- improve retinal clarity
- improve VA
- decrease strab
- obtain sensory fusion
- improve motor fusion
Prescribing for optimum lenses?
- full cyclo rx in preschoolers
- if >5yo -0.5 to -1D symmetrically
ST + myopia rx?
- least plus + ADD: bifocal
- may increase angle
XT + hyp rx?
least plus to best VA
Relieving, correcting, training prism?
- Relieving: partial prism
- correcting: full prism
- training: excess prism to train fusion
if no sensory function with prism: DO NOT PRESCRIBE
- improve accomm
- improve OM and hand eye
- improve pursuit and saccades
- reassess sensory function after phase 2 goals achieved
- establish normal peripheral fusion
- eliminate peripheral suppression
- eliminate AC
- stabilise normal peripheral sensorimotor skills
How to manage AC?
- cant train out AC and leave deviation - diplopia
- treated alongside suppression
- tx: overprescribe prism, synoptophore flashing, after images on fovea, occlusion if constant strab
Phase 3 tx?
- dark room, no central contours or small details
- target at obj angle for ST, ortho for XT
VT steps for phase 3?
- 1. appropriate enviro: light, dark etc
- 2. suppression breakers: flashing, moving, prism out of zone
- 3. mental hold: get them to see it once, then try get them to hold it, hold it counting, see if they can hold it with prism
- 4. increase sensory and motor fusion demand: BI/BO, flippers, use smaller targets
- establish normal central fusion
- eliminate central suppression
- improve shallow amblyopia
- stabilise efficient central sensorimotor skills
Phase 4 tx?
- 1. if suppression broken in stage 3-> red/green targets- use smaller and smaller targets- more small detail, central contours
- 2. add/remove prism: increase fusional ranges
- 3. reassess angle- sensory fusion increases, angle decrease, amb improves
Phase 5 considerations?
- relieving prism?
- strab surgery?
- stabilise accom and vergence efficiency?
Phase 5 prism?
- still may be small deviation left by this stage- prescribe prism to get eyes to fuse
- <20PD prescribe
- >20PD surgery
Surgery in phase 5 amount of deviation?
- >20PD ST
- >25PD XT
- >10PD vert
What are the 3 groups referred for surgery?
- 1. cosmesis cure
- 2. poor prog for functional cure: large angle and >6/24
- 3. good prog: large angle with bcrx, shallow amb, good sensory fusion, motor fusion ranges expanded
How to stabilise accom and vergence efficiency in phase 5?
- Home maintenance
- Home AVT: antisuppression, vergence ranges, 3x10-20min/week
When to re-evaluate after stage 6?
- 1M, 3M, 6M, 1Y
- 6M for adults
- 1Y adults