Cross eyes Crossword

Dr. Madhu KarnaConsultant Pediatric Ophthalmologist

There are many roads to orthophoria. If we only knew:

• The trick to measure correctly.

• The tip when to investigate.

• The clue to avoid being trapped in a complicated result of a seemingly simple case.

What do you do when you see this kind of a patient?

Or one like this

If you operate what you measure over glasses then

• If glasses are plus Measured deviation = True deviation – 2.5 D

% [D-lens power]• If glasses are minus Measured deviation = True deviation + 2.5 D

%

In clinical practice it is the measured deviation that is found first and true deviation must then be calculated

Plus lenses decrease and minus lenses increase the measured deviation.

Spectacle lens power

True deviation as %of measured deviation

To find true deviation

Change

measured

deviation by Example

-20 67 Decrease by 33%

4/6

-10 80 Decrease by 20%

4/5

PLANO 100 No change 4/4

+10 133 Increase by 33%

4/3

+20 200 Increase by100%

4/2

• High Plus lenses in both exo & eso – M D <T D [undercor]

• High Minus lenses in both exo & eso – M D >T D [overcor]

• This becomes Sx significant with refractive errors of + 5 d

• This formulae deal with strabismus measurements with distance fixation

• While fixing for near the visual axes no longer pass through optical centre of lenses, prismatic effects get important.

If you have not measured with C L,

with this formulae you can still achieve orthophoria

Beware of a patient like this before you operate her

• High myope – Status post OD:CLE, OS:Lasik

DO IT BUT AFTER MRI

• Coronal/transverse/parasagittal T1 weighted high resolution MRI of orbits

• Dynamic /motion MRI –nine gazes• Intraoperatively,

– Distances betn insertion sites of EOMs– Distances of EOMs from corneal limbus

• MRI findings of dislocation of recti to decide surgery

• Postoperative MRI –for alignment & motility

• New methods of eye muscle surgery in

– high myopic patients with esotropia and hypotropia

– with respect to pathological findings in high resolution MRI

• Herzau/Ionnakis – intraoperatively abnormal path of LR. Good results with R&R + suprapositioning of LR– Verified by MRI scan

• Pathophysiology– with increase in Axl- bubble like superotemporal

distension of globe-in middle & post segment ,– causes increased stretching of LR with downward

dislocation– sparing the ant. segment with insertion sites– accumulation of retinal degn betn insertion of SO & IO

A

P

L

M

New Approach in Strabismus Surgery in High Myopia*

Modified retroequatorial myopexia, in addition to conventional R&R surgery for dislocated horizontal recti in high myopes, is a promising & effective surgery

* T H Krzizok,H Kaufmann,H Traupe ,British Journal Of Ophthalmology 1997 Vol 81 Pg 625-630

Investigate the track of the muscles before you set them straight

New Approach in Strabismus Surgery in High Myopia

T H Krzizok

H Kaufmann

H Traupe

British Journal Of Ophthalmology 1997 Vol 81 Pg 625-630

This squint may trap you by seeming simple but

Before you operate this patient

Just remove the glasses

• High hyperopia with Accomodative Esotropia with Consecutive ExotropiaExotropia

• Reduce hyperopic power by half

• If exotropia still manifest or there is a drop If exotropia still manifest or there is a drop in visual acuity then operate on the in visual acuity then operate on the consecutive Exotropia after measuring consecutive Exotropia after measuring over maximum cyclopegic refraction.over maximum cyclopegic refraction.

Thank you

May God bless you with many more ortho eyes