History
Patient: 22 year old Female Medical Student
Reason for Visit: Patient returning for a 3 month review with complaints of eye strain that is worse than before even with glasses, intermittent headaches towards the end of the day and horizontal diplopia.
Initial Visit 3 months ago: Trouble focusing in the distance, severe eye strain when reading, intermittent headaches, RE twitching, both eyes felt irritated and watery
No other relevant information regarding GH, POH or FOH.
Clinical Assessment
Pretest
Ocular Motility: Full
Pupils. PERRLA DCN
NPC: 12/15/17cm
Cover Test: Exophoria with mod recovery
Refraction
R. +0.25/-0.25 x 178 = 6/6 L. plano/-0.25 x 25 = 6/6
Additional Tests
Prism Cover Test sc D: Orthophoric
N: 8PD Exophoria
Stereopsis: 40 sec of arc
AC/A: -2: 4exo -1: 7exo 0: 8exo +1:11 exo (blurr)
AC/A Ratio Calculation: (8-4)/2 = 2:1
Prism Fusional Range (blur/Break/Recovery)
Distance: BI 6/10/6 BO 6/10/1
Near: BI 6/20/16 BO 6/20/8
Differential Diagnosis:
· Convergence Insufficiency
· Accommodative Excess
· Large Phoria
· Uncorrected Refractive error
· Dry Eye
· Supranuclear Palsy
· Demylination
· Myasthenia gravis
· Old Strabismus surgery
Management
Initial Management
1. Full Time: SVD (4PD BI) + UCSC
2. Pencil Push Up Excercises
3. Systane prn
4. Review 3/12
After 3 month review
1. Stop using the base in glasses
2. Vision Therapy in Clinic for min 10 visits
a. Stereograms at home and in clinic with prisms
b. Fusional training with Prisms
3. Goal: Increase Positive Fusional Amplitude and NPC
Discussion
Why did base in prisms not work?
Base in prisms help the eye to converge less than required for binocular single vision. Does not train the eyes to improve convergence or fusion
Cochrane Database: Base in reading glasses was no more effective than placebo reading glasses in improving clinical signs in children
Why did Pencil Push ups not work?
Pencil push up stimulates convergence only, does not induce diplopia or physiological diplopia for fusion training to occur.
Convergence Insufficiency Treatment Trial (CITT): Office based vision therapy more effective than pencil push ups
What tools are used for Convergence Insufficiency Training?
To improve Jump Convergence
· Balfour Pins
· Brocks Strings
· Two Finger Jumps
To improve Fusional Convergence
· Prism Fusional Training
· Stereograms with prism
What is the recommended treatment regime?
According to CITT
· Home based: 15min Daily
Pencil Push ups
Computer Vision Therapy Program
· In Clinic: 60 min à Average 12-24 visits
Mixture of all the orthoptic therapy
Modified to fit in with Specsavers Model
· Home Training with Stereogram
Interval Training: 30sec hold, 30 break for 15min
· In clinic once a week x12 weeks
10min Stereograms with prism
10min Fusion Training with Prism
Measure PFR and NPC Weekly for compliance
Did it work?
After 5 weekly visits the patient improved her near point of convergence and positive fusional range at both distance and near. The patient was then asymptomatic and was happy to cease in-clinic therapy. She did stereograms once a week for 15min as maintenance therapy at home.
Week |
BO PFR(Near) |
NPC |
1 |
6/25/8 |
17cm |
5 |
30/40/- |
7cm |
Table showing results of PFR and NPC measured at weeks 1 and 5
Normative Values: PFR Near: 35-40PD BO NPC: <10cm
References
- CITT. A Randomized Clinical Trial of Treatments for Symptomatic Convergence Insufficiency in Children. Arch Ophthal. 2008:126(10):1336-1349
- Ghadban R, Martinez J, Diehl N, Mohney B. The Incidence and Clinical Characteristics of Adult Onset Convergence Insufficiency. Am Ac Oph. 2015:122:1056-1059
- Gwiazda S. Non surgical interventions for convergence insufficency. Cochrane Database. 2011:(3):1-53
- Huston P, Hoover D. Treatment of Symptomatic Convergence Insufficiency with Home Based Computerized Vergence Therapy in Children. AAPOS. 2015:19(5):417-421
- Lavrich J. Convergence insufficiency and its current treatment. Wills Eye Inst. 2010:7
- McGregor M. Convergence Insufficiency and Vision Therapy. Paed Clin NA 2014:61(3):621-630