Strabismus also called as squint.

Strabismus is defined as a misalignment of the eyes. Strabismus also called as squint.
Orthophoria – Implies as perfect ocular alignment without efforts.Strabismus consists of two subgroups.
Having a squint can really affect many aspects of your life, whatever age you are. When you are a young child you may find it hard keeping an eye on where the ball is in a game of football and as you get older it could cause problems for you in the work place or when you are looking at a computer screen, playing games or checking emails. To be offered the chance to improve your situation would truly be welcomed. Below is the description of the two subgroups.

1.Hetrotropia – this is a manifest squint.
Esotropia – deviation of eye towards inside.
Exotropia -- deviation of eye towards towards outside.
Hypertropia-- deviation of eye towards upside.
2.Hetrophoria—this is a latent ocular deviation. Eye alignment is maintained with fusional effort.
Esophoria – inward deviation of eye when fusion is disrupted.
Exophoria-- outward deviation of eye when fusion is disrupted.
Hyperphoria-- upward deviation of eye when fusion is disrupted.
Incyclophoria-- Intortional movement of eye when fusion is disrupted.
Excyclophoria-- Extortional movement of eye when fusion is disrupted.

Concomitant Strabismus
Esotropia
Exotropia
Non Comitantant Strabismus ( Paralytic)
Third Nerve Palsy
Forth Nerve Palsy
Sixth Nerve Palsy
Non Comitantant Strabismus ( Restrictive)
Duane’s Retraction Syndrome
Brown Syndrome
Double Elevator Palsy

Infantile Esotropia

A Pattern Deviations

V Pattern Deviations

AV Pattern Management

Dissocited Vertical Deviations(DVD)

Dissocited Horizontal Deviations(DHD)

Restictive Thyroid Myopathy

How to examine a strabismus patient?

Management Of Eso Deviations

Complications Of Strabismus (Squint) Surgery

Squint Surgery Video: Medial Rectus Recession Limbal Approach

Squint Surgery Video: Lateral Rectus Resection Limbal Approach

Classification Of Esotropia (Concomitant)

Accommodative Esotropia

Non- Accommodative Esotropia

1. Refractive
A. Fully Accommodative Refractive Esotropia With Normal AC /A Ratio

B.Fully Accommodative Refractive Esotropia With High AC /A Ratio

2. Partially Accommodative Refractive Esotropia

3.Non Refractive Accommodative Esotropia

A. Non Refractive Accommodative Esotropia With Hyper Accommodative (High AC/A Ratio)

A. Non Refractive Accommodative Esotropia With Hypo Accommodative ( Normal AC/A Ratio)

1.Essential Infantile Esotropia

2.Basis Esotropia

3.Microtropia

4.Convergence Excessive

5.Divergence Insufficiency

6.Convergence Spasm

7.Sensory Esotropia

8.Consecutive Esotropia

9.Cyclic Esotropia

10.Acute Onset Esotropia

Accommodative Esotropia

1. Refractive

A. Fully Accommodative Refractive Esotropia With Normal AC /A Ratio

• Age of onset about 2.5 years range 6 months to.
• AC/A ratio is normal
• Hypermetropia is usually +4.00DS to +7.00DS.
• Near and Distance deviation is usually same or many varies less than 10Δ
Treatment
• Fully corrected by optical correction.

B.Fully Accommodative Refractive Esotropia With High AC /A Ratio
• Hypermetropia with High AC/A ratio.
• Near deviation is more than distance deviation usually (>10Δ)
Treatment
• Distance deviation is usually corrected glass.
• For remaining near deviation , near addition is added in glass (Executive Bifocal)

Fully accommodative refractive esotropia with high AC /A Ratio for distance without spects ( Pic. Curtsey Dr Sudhir Singh)

Fully accommodative refractive esotropia with high AC /A Ratio for near without Spects ( Pic. Curtsey Dr Sudhir Singh)

Fully accommodative refractive esotropia with high AC /A Ratio for distance with Spects ( Pic. Curtsey Dr Sudhir Singh)

Fully accommodative refractive esotropia with high AC /A Ratio for near with Spects ( Pic. Curtsey Dr Sudhir Singh)

2. Partially Accommodative Refractive Esotropia

• Age of onset about 2.5 years( range 6 months to7 years).
• AC/ A ratio is normal
• Hypermetropia is usually +4.00DS to +7.00DS.
• Near and Distance deviation is usually same or many varies< 10Δ
Treatment
• Partially corrected by optical correction
• Surgery for residual deviation
Calculate amount of surgery by SquintMaster Software

3.Non Refractive Accommodative Esotropia

A. Non Refractive Accommodative Esotropia With Hyper Accommodative (High AC/A Ratio)
• High AC/A ratio.
• Near point of accommodation is normal.
• Esotropia for near but eyes are straight for distance.
Treatment
• Bifocal glasses or miotics

A.Non Refractive Accommodative Esotropia With Hypo Accommodative ( Normal AC/A Ratio)
• Normal AC/A ratio.
• Remote point of accommodation is normal.
• Esotropia for near but eyes are straight for distance.
Treatment
• Bifocal glasses or miotics

Cycloplegic refraction in Children
Age below 6 years –
• Cycloplegic under atropine 1% ointment twice a day (3 mm. length of ointment) for 3days.
• Detect only working distance from refraction revealed by retinoscopy.
Age above 6 years –
• Detect only working distance from refraction revealed by retinoscopy.

Infantile Esotropia Clinical features: 1.Onset between birth and six months of age. 2. Large size (greater than 30 dioptres). 3. Stable size. 4. Either alternation or fixation preference may be present 5. Neurologically normal 6 The patient may or may not have any or all of the following associated conditions: Oblique muscle dysfunction, vertical incomitance, dissociated vertical deviation, asymmetric optokinetic nystagmus, torticollis. The patient may or may not have any or all of the following associated conditions: Oblique muscle dysfunction, vertical incomitance, dissociated vertical deviation, asymmetric optokinetic nystagmus, torticollis. 8. Initial alternation of the squint present with crossed fixation - i.e. the affected individual uses the left eye to look right and the right eye to look left. 9. Limited potential for binocular vision. Differential Diagnosis 1. Sixth cranial nerve palsy 2. Primary Constant esotropia. 3. Duane's Syndrome . 4. Nystagmus Blockage Syndrome 5. Esotropia arising secondary to central nervous system abnormalities (in cerebral palsy for example).
	Infantile Esotropia esotropia with right Oblique muscle overaction grade 4 ( Pic. Curtsey Dr Sudhir Singh)

	Infantile Esotropia esotropia ( Pic. Curtsey Dr Sudhir Singh)


	Infantile Esotropia esotropia with left Oblique muscle overaction grade 4 ( Pic. Curtsey Dr Sudhir Singh)

Management
When to operate ?
Ing [1] and Helveston, [2] favour a prescribed approach often involving multiple surgical episodes whereas others prefer to aim for full alignment of the eyes.
According to Dutch study (ELISSS) [3] compared early with late surgery in a prospective, controlled, non-randomized, multi center trial and reported that children operated early had better gross stereopsis at age six as compared to children operated late. They had been operated more frequently, however, and a substantial number of children in both groups had not been operated at all.
Surgical dose : you can calculate by SquintMaster Software.
Caution: If age of child is below 2 years then take measurement from limbus for recession as SquintMaster provide measurement from muscles insertion.

Reference:
1. Ing M.R.; Early Surgical Aignment for Congenital Esotropia; Ophthalmology, 1983; 90: 132-135
2. Helveston E.M.; Ellis F.D.; Patterson J.H; Weber, J.; Augmented Recession of the Medial Recti
3.Simonsz HJ, Kolling GH, Unnebrink K. Strabismus. 2005 Dec;13(4):169-99

Basic Esotropia
1. Deviation is equal for distance and near . if there is difference then it is less the 15 Δ.
2. Refractive error not significant .

Management
• Medial rectus recession unilateral / bilateral depending upon magnitude of esotropia.
• Medial rectus recession with lateral rectus resection calculate amount of surgical dose by squint master.

Convergence Excess Non Accommodative Esotropia
• Distance – small esotropia or orthophoria.
• For near – Esotropia
• AC/A ratio normal / low
• Near point of accommodation . normal (33cm.)

Treatment
Bilateral Medial rectus recession Surgical dose according to magnitude of deviation.
Surgical dose : you can calculate bySquintMaster Software.
Divergence Insufficiency Non Accommodative Esotropia
• Esotropia for distance .
• Orthophoria or no deviation of near.
• Reduced fusional divergence amplitude .
• Biletral abduction are full.
• No neurological deficient

Treatment
• Prisms
• Biletral Lateral rectus resection.
• Surgical dose according to magnitude of deviation.
• You can calculate amount of surgery by SquintMaster Software

Consecutive Esotropia
Esotropia following surgical overcorrection of exotropia called consecutive esotropia.
Treatment
1.Wait at least for six month if deviation is not much.
2. Surgical treatment according according to deviation if it is significant
Surgical dose : you can calculate by SquintMaster Software.
Cyclic Esotropia
In cyclic esotropia there are alternating episodes of esotropia followed by orthophoria. Each episode lasts for around 24 hours. Eventually cyclic esotropia developed in to constatant esotropia.
Treatment
1. Observation in cyclic phase
2. Surgery when it become constant esotropia.

Microtropia
Microtropia also called as monofixation syndrome.
Clinical features--:
1. Esotropia—About 8 Δ or less. Esotropia may or not may be detectable on cover test.
2. Anisometropia with amblyiopia
3. Central suppression scotoma of deviating eye it may be detected by
4.ARC
Diagnosis
1.4D Prism Base Out Test
2.Bagglini Test

Prism Base Out Test
Place 4 D prism base out in front of right eye
Situation 1
• Inward movement of right eye
• Outward of movement left eye according to hering’s law .Then show fusional inward movement of left eye.
Inference of situation ---- Right eye is normal.
Situation 2 – If no movement, then central suppression scotoma of right eye.
Repeat same procedure for left eye
Treatment
Correction of refractive error with ambyopia management.

Download Patient Case Sheet Performa

References

Ophthalmology Surgery Videos on YouTube