Convergence Insufficiency Flashcards

Question

When would we say a strabismus was secondary?

Answer 1

If someone had a 3BI XT would say Primary CI but if someone had like 15BI XT you’d call this secondary

Answer 2

The first line of treatment in primary CI is orthoptic exercises, if these are not successful prisms can be trialled. It is rare surgery or BT are done in patients with primary CI, these patients often have poor surgical prognosis as they have reduced fusional reserves and ability. More of a fusional reserve problem opposed to muscle issue so surgery and BT not needed; managed conservatively more often

Answer 3

- Orthoptic exercises - Prisms - Surgery - Botox

Answer 4

- Large underlying deviation? – surgery for more control - Vertical deviation? - Poor general health? 2° CI (2ndary CI) does not prevent exercises being attempted but may limit prognosis

Answer 5

- Pen to nose (smooth vergence) - Jump exercises & dot card (jump vergence)

Answer 6

Used in convergence insufficiency with the aim to be able to converge closer to the nose each time. Improve near point convergence. By the end the patient should be able to focus closest to nose and keep it single. e.g. pen-to-nose

Answer 7

To be able to change focusing distances more quickly whilst maintaining single vision e.g. jump exercises and dot card

Answer 8

- Refine control - Improves BO fusional reserves and positive relative convergence - Alternative to gradual and jump convergence as NPC improves BUT need reasonable NPC for stereograms

Answer 9

- Exercise convergence using a makeshift BO Fresnel prism bar - Gradually provide patient with stronger BO Fresnel prisms

Answer 10

- Rx should be worn - Pt should have BSV at Nr - Physiological diplopia can be used as a check if pathological diplopia is not appreciated i.e. patient suppresses at break point - Must explain the exercises and explain that symptoms may worsen initially

Answer 11

Explain and demonstrate exercises to patient Allow patient to practise the exercises with you Check at each visit that they’re doing it right Give leaflet with contact details

Answer 12

1 - 2 minutes per session, 3 - 4 times daily Relaxation Look at a distance target to prevent inducing convergence spasm See in 3-4 weeks (want to ensure no convergence spasm and that they’re on top of doing the exercises) then gradually increase length between visits

Answer 13

- BSV present - Symptomatic - Motivated and cooperative - Understands exercises - Normal accommodation for age - Able to attend frequently

Answer 14

- Not suitable for young children - Older patients can still benefit from CI exercises, however accommodation cannot be used as effectively to aid convergence

Answer 15

Telephone consultation or video consultant is an option for patients who cannot attend clinic, especially if you have done the 3-4 week review and know they’re not getting spasm and they’re doing the exercises correctly.

Answer 16

- If normal NPC and normal fusional amplitudes achieved stop exercises for 4 weeks - If symptoms re-occur patient may need maintenance exercises - Discharge

Answer 17

Children: 59.5% - 97.6%

Answer 18

Children: 66.7% - 84.4%

Answer 19

Randomised control trial looking at reducing symptomatic CI through orthoptic exercises The most improvement tends to happen within the first 4 weeks of treatment but is worth persevering and encouraging patient to 16 weeks. (65.90% asymptomatic at 4 weeks but 97.60% at 16 weeks)

Answer 20

Randomised control trial 12 week therapy: - office-based vision therapy - office-based placebo vision therapy - home-based pencil push-ups All groups reported demonstrated improvement in symptoms on CISS (including placebo patients) but NPC in office-based therapy was the only statistically significant one (even the home-based pencil push-ups didn’t have improvement so ??? to the effectiveness of these) Significant improvement was found in NPC, PFR and CISS (questionnaire) in Orthoptic therapy group only. = Don't do pen push-ups alone but incorporate other exercises into the routine. Time & effort is needed

Answer 21

Significant improvement was found in the CI symptom survey and NPC in Office-based orthoptic therapy with home reinforcement only 60-minute in-office therapy visit with additional prescribed procedures to be performed at home for 15 minutes a day, 5 days per week

Answer 22

- Most effective exercises were simple vergence exercises - Binocular push up, binocular jump vergence, near and distance vergence facility (stress single vision) - Improved convergence and accommodation – should give 2 to 3 exercises to each patient (usually pen push-up, stereograms or dot card) - ‘Effort’ had greater influence on responses than any exercise groups – explains CITT (2008) findings - Treatment resolving blur had no/minimal effect - Groups which exercised conv and accom were the least effective than concentrating on single visual skill

Answer 23

- 1 year follow up - 84.4% of those in 12-week orthoptic home and office therapy group were asymptomatic 1 year after discontinuing exercises

Answer 24

- After 18 hours of vision therapy CI patients can fixate faster after treatment - Before treatment CI converged slower but there was no difference in divergence speed between CI and controls - Found increased activity in FEF, Cerebellum and the Brainstem

Answer 25

Relieve some of the effort needed to converge Decrease the amount of base out prism fusion range needed for comfortable vision

Answer 26

- Sheard’s criterion: Prism strength = 2/3 exophoria minus 1/3 near BO fusion range. (Sheard, 1930) - Give the minimum strength allowing for comfortable near BSV

Answer 27

Randomly assigned 64 young adults 18 to 40 years of age to wear either base-in prism reading glasses or placebo reading glasses for all near work activities lasting more than 15 minutes for 12 weeks, with the primary outcome visit after 12 weeks prism glasses group had significantly less symptoms compared with the placebo glasses group at three months; no evidence of difference was found in NPC or PFV.

Answer 28

Found to be less effective in children (CITT, 2005)

Answer 29

Effective in presbyopes with CI (Teitelbaum et al, 2009)

Answer 30

- Secondary CI - Large Nr X >12PD

Answer 31

- Primary CI - Poor response to prisms (defective motor fusion)

Answer 32

- Medial rectus plication - (Slanted) Medial rectus resection Can be unilateral or bilateral

Answer 33

Plication tightens the MR muscle by folding the muscle on itself, then suturing it to the sclera. No cutting or disinsertion of the muscle is required

Answer 34

Rajavi et al. (2021): - Minimally invasive, quicker and reversible - Less risk of anterior ischaemia as the vascularisation of the eye is preserved - Has been performed under local anaesthetic - Less conjunctival swelling

Answer 35

- Upper edge of MR resected according to the distance exodeviation - Lower edge of MR resected according to near exodeviation - So lower edge resected more than upper edge - MR reattached at its original insertion

Answer 36

Nemet and Stolovitch (1990) not successful in collapsing the near distance difference

Answer 37

Slanted bilat LR recession (upper edge recessed according to dist angle; lower edge to near angle) - Significantly better at correcting dist angle (p=0.054) compared to Augmented bilat LR recession, Unilat MR resection & LR recession. - Not significantly better at correcting near angle and near-dist diff - Assoc with post-op A and V patterns

Answer 38

Augmented to near angle - associated with post-op consecutive ET & diplopia

Answer 39

Assoc with post op under corrections but simplest therefore recommend this

Answer 40

- 57% improved at 1st follow up (median 47 days post BT) - 23% improved at 2nd follow up (median 174 days post BT) Repeat injections may be required, may not be suitable for children and botox may leak into other areas if given lying down

Convergence Insufficiency Flashcards

(64 cards)