SQUINT NOTES

                           SQUINT

DEF-

Misalignment of the two visual axes at the point of regard.

ORTHOPHORIA-

Ocular alignment without effort.

HETEROPHORIA [PHORIA ]-

Tendency of the eyes to deviate.Ocular alignment is maintained with effort.

HETEROTROPIA [ TROPIA]-

Eyes are misaligned.It is a manifest squint.

Phoria becomes a tropia if-

1.Inadequate ms strength

2.Stimulus for fusion is weak [ UL blurred vision]

3.Breakdown of neurological pathways.

VISUAL AXIS-

Passes from the fovea, thru the nodal pt to the fixation pt.It cuts the cor nasal to the centre.

ANATOMICAL AXIS-

Passes from the posterior pole thru the centre of cornea.

ANGLE KAPPA-

Angle subtended by the visual &anatomical axes.

5 deg

Positive angle kappa- Fovea is temporal to the post pole

Neg angle kappa-Fovea is nasal to the post pole.

LISTING PLANE-

Imaginary plane passing thru the centre of rotation of the globe.

3 planes-

*  Horizontal

*  Vertical

* Torsional

FICK’S AXES-

3 axes-

*  Vertical –Z axis-Globe rotates rt & lt

*  Horizontal- X axis-Globe rotates up & down

* Antero-posterior-Y axis-Torsional movt

SPIRAL OF TILLAUX-

Imaginary line joining the insertions of 4 recti away from the limbus.

MR- 5.5MM

IR- 6.5MM

LR- 7MM

SR-7.7mm

ACTIONS OF EOM-

MUSCLE	PRIMARY ACTION	SECONDARY ACTION
MR	ADDUCTION	-
LR	ABDUCTION	-
SR	ELEVATION	INTORSION [SIN] ADDUCTION [RAD]
IR	DEPRESSION	EXTORSION ADDUCTION
SO	INTORSION	DEPRESSION ABDUCTION
IO	EXTORSION	ELEVATION ABDUCTION

23 deg abduction→ SR acts only as elevator

                                IR acts only as depressor

67deg adduction→SR acts only as intorter

                             IR acts only as extorter

SR & IR form an angle of 23deg with optical axis

SO & IO form an angle of 51deg with the optical axis

51 deg adduction→SO acts only as depressor

                               IO acts only as elevator

39 deg abduction→ SO acts only as intorter

                                Io acts only as extorter

OCULAR  MOVTS-

DUCTIONS- Monocular movts

Include- Add, abd,elev, dep, intorsion & extorsion

VERSIONS-Binocular & conjugate movts  [in the same dir]

• Dextroversion
• Laevoversion
• Dextroelev
• Dextrodepression
• Laevoelevation
• Laevodepression
• Dextrocycloversion
• Laevocycloversion

VERGENCES-Binocular & disjunctive movts [ in the opp dir ]

• Convergence
• Divergence

AGONIST-Primary ms moving the eye in a given dir

ANTAGONIST-Acts in a dir opp to the agonist

Eg→ RMR & RLR

SYNERGIST-Ms of the same eye that move the eye in the same dir.Eg→ RSR & RIO

YOKE MS-Pair of ms , one in each eye, that produce conjugate movts

Eg→ RSR & LIO

SHERRINGTON’S LAW OF RECIPROCAL INNERVATION-

Increased innervation to an EOM [ RMR] is accompanied by a reciprocal decrease in innervation to its antagonist [RLR].

Clin appl- Duane’s retraction syn

HERRING’S LAW OF EQUAL INNERVATION-

During any conjugate eye movt ,equal & simultaneous innervation flows to the yolk ms.

Clin appl-

1. In paralytic squint, secondary deviation is more than primary deviation.

PRIMARY DEVIATION-

Deviation of the  squinting  eye with the normal eye fixating.

SECONDARY DEVIATION-

Deviation of the normal  eye under cover with the squinting eye fixating.

2. Inhibitional palsy of CL antagonist [ i.e antagonist of yolk ms of the paretic ms ]

      For  eg-

PARETIC MS	YOLK MS    [opp eye ]	ANTAGONIST OF YOLK MS [same eye ]
RLR	LMR	LLR
RSO	LIR	LSR

CONFUSION-

Simultaneous appreciation of two superimposed but dissimilar images caused by stim of corresponding retinal points by images of diff objects.    

DIPLOPIA-

Simultaneous appreciation of two images of the same object due to stim of non-corresponding points

CORRESPONDING POINTS-

Areas on each retina that share the same subjective visual dir.

HOROPTER-

Imaginary plane, all points on which stimulate corresponding ret elements & are seen single.

PANUM’S AREA-

Area in front & behind the horopter which allows sensory fusion [ I.e diplopia does not occur]  despite the disparity

                DIPLOPIA

-In diplopia, one image is distinct, k/as true image & other image is false ,k/as false image

CLASSIFICATION OF DIPLOPIA-

1. Physiological –read from notes on BSV
2. Pathological- Uniocular

                        -Binocular

Binocular- homonymous [uncrossed]

               -heteronymous [crossed]

1 )  PHYSIOLOGICAL DIPLOPIA-

     Objects which are not within the area of fixation are double.

2)   PATHOLOGICAL DIPLOPIA-

a)   UNIOCULAR DIPLOPIA

• Diplopia with only one eye open
• Occurs wen 2 images of the same object form on 2 diff parts of the retina.
• Causes-

• Immature cortical cataract [d/t multiple water clefts within the lens]
• Subluxated clear lens [Partly phakic & partly aphakic]
• Large peripheral iridectomy
• Iridodialysis
• Polycoria
• RD d/t dialysis wen retina becomes inverted.

b)  BINOCULAR DIPLOPIA-

• Diplopia with both eyes open
• Image of an object does not fall on corresponding ret pts
• Image falls on the fovea of  one eye & extrafoveal area of other eye
• Causes`-

• EOM paresis / paralysis
• Displacement of the eyeball by a space occupying lesion in the orbit, # orbital wall or by pressure of finger
• Mech restriction of OM by-Pterygium,symblepharon & TED
• Anisometropia –aphakia UL

    Convergent squint→ Uncrossed diplopia [as image forms on   

                                                                        Temporal retina]

    Divergent squint→ Crossed diplopia [as image forms on nasal

                                                                  Retina]

1. Paradoxical diplopia-not expected in a particular diplopia [ARC]
2. Double diplopia – dip in both upgaze & downgaze [blow-out #]

INV-

  1)  RULES OF DIPLOPIA CHARTING-

1. Max separation towards the action of paralysed ms
2. Farthest image belongs to the paralysed ms
3. Faint image belongs to the paralysed ms

PLOTTING OL DIPLOPIA CHART-

• Red-green goggles
• Semi-dark room
• Fine linear light ( candle) is shown from a dist of 4ft.
• Light is movec from the prim pos into all 8 dir of gaze
• Pt has to comment on the pos,brightness & separation bet the red & green images.
• From the pt’s comments,the examiner notes-

-diplopia is hetero or homonymous

-which image is higher & which is lower

-which dir of gaze the separation is max

Disadv of this test-

1. Quantitative test
2. Req intelligent pt
3. Not possible in colour blind
4. Not useful in cong palsies & longstanding duration bcos d/t deep suppression diplopia cannot be elicited

Rx-

1. Symptomatic relief- occlusion of worse eye

                                  -prism correction- small dev in paralytic sq

2. Surgical-

Ms weakening & strengthening surgeries

CLASSIFICATION OF SQUIN`T-

1. CONCOMITANT

Angle of deviation remains constant in all dir of gaze

B.INCOMITANT

Angle of deviation varies with the dir of gaze

1. Paralytic
2. Restrictive
3. Spastic

DIFFERENCES	PARALYTIC	COMITANT
1.Precipitating event	Trauma or disease	Developmental
2.Age	Infants or childn	Adults
3.Diplopia	+	-
4.Abnml head posture	+	-
5. False projection	+	-
6.Angle of squint	Varies	Constant
7.OM	Restricted in dir of action of paralysed ms	Normal & no restriction
8.Angle of dev	PD < SD	SD  =   PD
9.Amblyopia	-	+

GRADES OF BSV-read from notes

I] Simultaneous macular perception-

   Ability to see images of two dissimilar objects simultaneously

II] Fusion-

   Ability to fuse two similar but incomplete images

III] Stereopsis-

     Depth perception

                    ECCENTRIC  FIXATION  [J-03]

DEF-Non-foveal fixation area assumes fixation over the fovea.

         -Patient looks past the object he has been asked to fix

TYPES-

1. PARAFOVEOLAR- Just outside the foveolar reflex
2. PARAFOVEAL-Outside but close to foveal wall
3. PARAMACULAR-On/just outside the rim of macula
4. PERIPHERAL-Outside the macula ,anywhere bet the macula & extreme periphery

*  Tested with the visuscope ,Haidinger’s brush or graticule  [star]of the o’scope, Maxwell spot method

*  Patient is asked to look into graticule after occluding the other  eye

* Normally the star or graticule coincides with the fovea if fixation is central

*  In eccen fix it will not coincide & will be anywhere on the nasal / temporal ret or above or below the fovea

*  The degree of eccentricity can be known from the concentric ring with which fov coincides

*  These rings are situated at a distance of ½ deg from each other

RX-

1. Red filter test-

–sound eye- occluded

• amb eye- red filter which excludes wavelengths < 640micrometer
• Red light does not stim peripheral ret .So fovea takes up fixation

2. Inverse occlusion-

-Sound eye- total occ 3-4 mo→ no effect→

-amb eye-total occ 6mo

3. Pleoptics
4. prisms + occln-

• sound eye- total occl
• amb eye- prism

                           III  NERVE  PALSY-case

ANATOMY OF III N-

• Entirely motor
• Supplies- MR, SR, IR, IO, LPS , sphincter pupillae & ciliary ms
• III n nucleus lies in the mid-brain at the level of superior colliculus
• 2 parts- main nuc

              -accessory nu-Edinger Westphal nu

PATHWAY-

1. FASCICULAR PART-

III n nucleus → Efferent → Red nucleus [BENEDIKT’S SYN ]→ Medial aspect of cerebral peduncle [WEBER’S SYN ]→ mid-brain

     B.BASILAR PART-

         15-20 rootlets arise in the interpeduncular fossa→coalesce → Large medial root & a small lateral root → unite & form a flattened nerve→ twist → Superior fib go inf & vice versa→ rounded cord→ passes in bet post cerebral A & superior cerebellar A→ interpeduncular cistern→ cavernous sinus

C.INTRACAVERNOUS PART-

Pierces post part of roof of cav sinus on lat side of post clinoid process→ descends on lateral wall of sinus above the IV n→divides into superior & inferior div with nasociliary n in bet→ middle part of SOF→ orbit

D. INTRAORBITAL PART-

   Superior div→ SR  

                             LPS

   Inferior div→ MR

                          SR

                           IR

                           IO→ MOTOR ROOT →ciliary ganglion

            III  NERVE PALSY

AETIO-

1. CONGENITAL-

1. Developmental aplasia or hypoplasia of III n / nu
2. Intrauterine trauma
3. Birth trauma-During labor, compression of the N at a point bet brainstem & entry of N into cav sinus
4. As a part of cerebral palsy
5. Intracranial inf-Meningitis & encephalitis

2. ACQUIRED-

1] NUCLEAR-

Causes- Metastatic

          -Demyelination

          -infarction

        WEBINO SYN-

• Inv paired medial rectus subnuclei
• Wall eyed Bil internuclear ophthalmoplegia
• Defective convergence & adduction
• CL weakness of elevation

   2] FASCICULAR –

       Causes- ischaemia

                  -Infiltration [ tumour]

                  -Inflammation

       BENEDIKT’S SYN-

• Lesion-Red nucleus
• I/L III n palsy + C/L tremors & jerky movts

WEBER’S  SYN-

• Lesion- cerebral peduncle
• I/L III n palsy + C/L hemiplegia & Facial palsy

     3]BASILAR-

    Isolated III n palsies are frequently basilar.

    Causes-  

1. Aneurysms of posterior communicating A-alway look for pupil
2. Extradural haematoma→ downward herniation of temporal lobe→ compresses the III n at the tentorial edge
3. DM→ pupil sparing

 ( Pupillary fib lie on the superficial part of the IIIn which is supplied by the pial Vs.Vasa vasorum supplies the main trunk of III n.DM & HT damage the vasa vasorum & thus spare the pupil,whereas pial Vs are damaged by aneurysms,trauma & uncal herniation & inv the pupil)

     4] INTRACAVERNOUS-

         Pupil is spared OR MAY BE INV -constricted

         Causes-

1. Pituitary apoplexy
2. Aneurysms
3. Meningiomas
4. Carotid cavernous fistula
5. Tolosa Hunt syn

       5] INTRAORBITAL-

           Causes-

1. Orbital tum
2. Pseudotum
3. Trauma
4. vascular dis

6] NEUROPATHIC-

1. Vascular causes-

 *  DM

 *  HT

2. HZO

3. Ophthalmoplegic migraine

4. First syn-BL prog ophthalmoplegia & variant of GBS

ISOLATED III N PALSY-

• DM
• HT
• Trauma
• Aneurysms at the juncn of post communicating A with ICA
• Idiopathic-25%
• Misc-tb, syphillis

PAINFUL OPHTHALMOPLEGIA- imp

1. Trauma
2. Aneurysms-Intracavernous carotid A

                        -Posterior cerebral A

                        -basilar A

  3.CCF

  4. Cavernous sinus thrombosis

  5. tumors

  6 HZO

  7. Weg gran

  8. Sarcoidosis

  9. Tolosa Hunt syn

10. pseudotum

11. Giant cell arteritis

12. DM

13.HT

14. Ophthalmoplegic migraine

PUPIL SPARING-[imp]

• DM
• HT
• Arteriosclerosis
• Coronary artery dis
• Hypercholestrolemia

    PUPIL INVOLVING-

• Aneurysm [post communicating A]
• Tumor
• Trauma
• Cavernous sinus lesion
• Pituitary apoplexy
• Orbital dis
• HZO
• Leukemia
• Ophthalmoplegic migraine

    C/F-

1. Ptosis  - [ d/t LPS palsy]
2. Ocular deviation- Eye turned DOWN , OUT & INTORTED
3. Restricted OM-

• Adduction- MR
• Elevation – SR & IO
• Depression- IR
• Extorsion- IR &IO

4. Pupil-fixed & dilated [ d/t paralysis of sphincter pupillae]
5. Accomodation lost [d/t ciliary ms]
6. Diplopia-crossed & horizontal
7. Abnormal head posture-

• Face turn – opp side
• Head tilt – same side                [IV n palsy- face turn & head

                                                       Tilt- opp side]

• Chin- elevated

ABERRANT REGENERATION OF III N-

Miswiring of axons from the prox portion to the distal portion of N

Significance-Suggests that it is a slowly compressive lesion   [MC- Meningioma or Aneurysm]

Other Causes-

• Trauma
• Congenital
• Not microvascular

    C/F-

• Pseudo-Graefe’s sign- UL retracts on down gaze. [d/t miswiring of N fib meant for IR with N fib going into LPS ]
• On adduction- Widening of PF
• On abduction-Narrowing of PF
• UL retraction accompanied by contraction of pupil.
• On upgaze- eyeball retracted & adducted.
• Pseudo-Argyll Robertson pupil- fixed dilated pupil,not reacting to direct & consensual

INV-

1. MRI- To rule out mass / aneurysm.

IND-

1. Pupil inv III n palsy
2. Pupil-sparing  in foll-

• < 50 yrs
• Incomplete III n palsy
• No improvement .> 3 mo

3. Aberrant reg III n (for meningioma & aneurysm)
4. Child < 10 yrs

2. Carotid angiography-

IND-

• > 10 yrs
• Pupil inv
• MRI is neg or shows a mass consistent with an aneurysm

3. CBC
4. ESR
5. Tensilon test- To rule out MG
6. BSL
7. Lipid profile

T/T-

1. CONSERVATIVE-

1. Wait & watch – 6-8 mo
2. Amblyopia t/t- Alternate patching
3. Diplopia – Alternate patch in visually mature pts with incomplete ptosis
4. Vit B
5. Sys steroids

2. SURGERY-

Shud be contemplated when squint measurement & diplopia are stable for 6 mo.

1. For exotropia-

LR Recession [12-14mm]

MR resection  [12-14mm]

SO Transposition if no result with above

2. For hypotropia-

• Supraplacement of horizontal recti
• SO tenotomy
• IR recession + SR resection

3. For ptosis-

-After correction of squint

-FRONTALIS SLING

DDs-

1. Myaesthenia gravis

• Diurnal variation
• Pupil never inv
• Ptosis ↑s on sustained upgaze

2. TED-

• Lid lag
• Exophthalmos
• FDT-positive
• No ptosis
• Inj over rectus ms

3. Chronic progressive external o’legia-

• BL
• Slowly progressive
• Ptosis
• O’plegia
• Pupil spared
• No diplopia

4. Pseudotumour-

• Pain
• Proptosis
• O’plegia

5. internuclear o’plegia

• UL or BL
• Adduction deficit with horizontal nystagmus of opp abducting eye

6. Giant cell arteritis-

• pupil not inv
• Motility def

           FOURTH NERVE PALSY[d04,j-03]

ANATOMY

• Entirely motor
• Only N to arise from dorsal aspect of brain
• Only N to cross completely on other side
• Longest & thinnest N [75mm]
• Nucleus- Midbrain at the level of inferior colliculus.

    PATHWAY-

1. FASCICULAR-

IV N nu→ Efferent→ pass posteriorly around aqueduct→ decussate in ant medullary vellum

2. PRE-CAVERNOUS-

Emerges from superior medullary vellum below the inf colliculus on the dorsal aspect of midbrain→ Tentorium→ bet post cerebral & superior cerebellar As→ lateral to cerebral peduncle

3. INTRACAVERNOUS-

Pierces dura on post part of roof of cavernous sinus→cavernous sinus→ lies below III N & above 1st div of V n→ SOF

4. INTRAORBITAL-

Orbit→ SO

          SUPERIOR OBLIQUE PALSY  [ j-03]

AETIO-

1. Congenital palsy
2. Head injury-Due to impact in the area of ant medullary vellum, where the two Ns decussate→ BIL IV N palsy
3. Vascular & neurogenic-

        * Aneurysms

        * Tumors

        * Myaesthenia gravis

        * Diabetic neuropathy

        * HZO

4. Idiopathic
5. Cavernous sinus & SOF syn

     C/F-

1. Cyclovertical deviation- Eye is elevated, adducted & extorted [UP ,IN & EXTORTED ]
2. Abnml head posture- Face turn- opp side

                                  -Head tilt-opp shoulder  ( IIIn-same side)

                                  -Chin –depressed

3.Diplopia-homonymous & vertical

                -Imge of inv eye is lower,uncrossed & intorted

                -Vertical separation increases on looking down

4.OM –For eg-left SO palsy-

  Prim pos- Left hypertropia [ left over right]

  Dextrodepression- Limited left depression

  Dextroversion- Left hypertropia increases [IO overaction]

5.PARK’S 3 STEP TEST / BEILCHOWSKY’S- notes

STEP -1

• Assess which eye is hypertropic in prim pos?
• Suppose- LHT
• This may be d/t weakness of-

→Depressor of LE- LSO & LIR

OR

→ Elevators of RE-RSR & RIO

Thus out of 8 ms ,4 are left

              RSR       RIO         LIO       LSR

              RIR         RSO       LSO       LIR

STEP 2-

• Determine whether LHT is greater in rt or lt gaze?
• WEAK RECTI OF SIDE OF FACE TURN
• WEAK OBL OPP TO FACE TURN
• For eg- LHT INCREASES ON FACE TURN TO RIGHT

→ weakness of right recti- RSR & RIR

OR

→ Weakness of left obliques-LIO & LSO

Out of 4 ms , 2 are encircled twice-  RSR  

                                                     &  LSO

STEP 3-

• Determine whether LHT  increases on lt or rt head tilt?
• Remember –All superiors are intorters & all inferiors are extorters
• Same side of head tilt→ Intorters
• Opp side                     → Extorters
• If LHT increases on head tilt to left, & almost absent on rt-

→ Weakness of left intorters- [SIN]- LSO & LSR

OR

→ Weakness of right extorters-RIR & RIO

The ms which is encircled thrice-LSO

Thus inv ms is LSO

3 STEPS-

1 SAME SIDE DEPRESSION

             OR

 OPP SIDE ELEV

2. SIDE OF FACE TURN- RECTI

  OPP                 “             -OBL

3. SIDE OF TILT- INTORTERS

OPP          “      - EXTORTERS

DIFF BET-

CONGENITAL SO PALSY	ACQUIRED SO PALSY
Amblyopia  +nt	Amblyopia –nt
Tilting of objects –nt	Tilting of objects +nt
Abnml head posture +nt	-nt
Vertical fusional amplitude> 1-3Prism dioptres	Vertical fusional amplitude = 1-3 PD
Long ,redundant & floppy SO tendon	-

EVALUATION-

7. Park’s 3- step test
8. Double Maddox rod test- For BIL SO palsy
9. hess screen test
10. Diplopia charting
11. B sugar, BP
12. CT scan-orbital dis
13. MRI-

T/T-

1. CONSERVATIVE-

1. Amblyopia
2. Prisms in spectacles
3. Diplopia

2. SURGICAL-

1. Congenital- SO Tucking
2. Acquired-

• Small Hypertropia→ IL IO Weakening
• Mod-large Ht→IL IO Weakening + IL SR Weakening

                                                                   OR

                                                              CL IR Weakening

-pure excyclotropia without Ht→Harada Ito procedure-Splitting & anterolat transposition of SO tendon

DDs-

1. Myaesthenia gravis
2. TED
3. pseudotum
4. Orbital #- H/O trauma,FDT-+
5. III n palsy
6. Brown’syn- Limited elev in add,FDT +
7. GCA

                  SIXTH NERVE PALSY

• Entirely motor
• Abducent nu –Lower part of pons ,beneath the floor of IV ventricle
• Closely related to fasciculus of VII N.
• PATHWAY-

1. FASCICULAR PART-

Abducent Nu → medial lemniscus→ Pyrimidal tract →7-8 rootlets emerge from the juncn of pons & medulla just lateral to the pyramidal prominence→ rootlets join to form one nerve

2. BASILAR PART-

N runs forwards, upwards & laterally thru the cisterna pontis bet the pons & occipital bone → Petrous temporal bone→ At the sharp upper border of petrous bone,it bends at right angles under the petroshenoidal lig.--> Pierces the post wall of cavernous sinus,lateral to dorsum sellae & superior to the apex of petrous bone.

3. CAVERNOUS SINUS-

Lies below & lateral to ICA→ passes thru middle part of SOF.Here it lies inferolateral to III n & nasociliary N→

4. ORBIT→ LR ms

                         SIXTH NERVE PALSY

AETIO-

1. CONGENITAL-

• Hypoplasia of VI nu
• Raised ICP
• MOBIUS SYN-VI n palsy

                            -Facial diplegia

                            -Microglossia

                            -loss of conj movts

2. ACQUIRED

NUCLEAR- IL VI N palsy

                  -IL VII N palsy

                  -Loss of conjugate movts

FASCICULAR-

FOVILLE’S SYN-

• lesion- dorsal pons
• IL VI N palsy
• Facial analgia [5th n]
• IL VII N palsy
• Deafness [8th n]
• Loss of conjugate movts [PPRF]

    MILLARD GUBLER’S SYN-

• Lesion – ventral pons
• IL VI N palsy
• CL Hemiplegia [pyramidal tr]

     VI N TRUNK-

• Infections-URI, immunization
• Vascular- HT, DM
• Multiple sclerosis

      BASILAR PART-

• Acoustic neuroma [1st symptom is hearing loss & 1st sign is reduced cor sensation]
• Nasopharyngeal tum
• # skull base
• GRADENIGO’S SYN-

• Neuralgia [5th n]
• IL VI N palsy
• Facial weakness [7th n]
• Deafness [8th n]

• Raised ICP

INTRACAVERNOUS  PART-

• Meningioma
• Aneurysm
• CCF
• Tolosa Hunt syn
• Vascular- DM,HT

[ Aneurysms commonly cause III palsy]

INTRAORBITAL-

• Orbital apex syn
• SOF syn

C/F-

1. Esotropia – D/t unopposed action of MR
2. Abnormal head posture-Face turn towards the action of paralysed LR
3. Diplopia- Horizontal & uncrossed
4. OM restricted. For eg- Left LR palsy

• Primary pos-Left esotropia
• Left abduction –Limited [LR Palsy]
• Left adduction –Nml

INV-Workup-

1. examine the V n-cor sensation
2. fundus exam-papilloedema
3. BP
4. BSL
5. Glycosylated hb

         6.MRI-

          IND-

• < 45 yrs
• VI N palsy + Neurolog sign
• BL VI N palsy
• Papilloedema

6. ENT exam
7. ESR & CRP -GCA

T/T-

1. CONSERVATIVE-

1. Wait & watch-6-8 mo
2. Vit B complex
3. Sys steroids
4. Patching in esotropic eye if no head turn to maintain BSV
5. Fresnel press-on prism –to correct diplopia in prim pos
6. Botulinum toxin into antagonist MR to cause its temporary paralysis→ temporary alignment

2. SURGICAL-

1RECESS-RESECT OPER

MR recession + LR resection

Max-6mm         max-9mm

Min-3mm          min-4.5mm

[Resect (strengthen ) the paralysed ms & recess (weaken) its antagonist]

2.MS TRANSPOSITION-

A) JENSEN’S PROCEDURE

*  SR, IR, & LR are split  for 8-10mm from their insertion

*  Superior ½ of LR is united with lat ½  of SR

*  Inferiof ½ of LR is united lateral ½ of IR

2. HUMMELSCHEIM PROCEDURE-

After splitting the SR & IR ,their lateral ½ are disinserted & sutured to  LR

3. BERENS & GIRARD

Full SR & IR are disinserted & sutured to LR

DDs-

1.TED

2.Myaesthenia gravis

3.Pseudotumour

4.orbital #

5.Duane’s retraction syn

6.Mobius syn

7.GCA

                                    FACIAL N PALSY

• Both a motor & sensory N
• 3 Types of nuclei- Main motor

                               -Parasympathetic

                               -Sensory

Main motor nucleus-

• Lies in the lower part of pons
• Part of the nucleus that supplies upper part of the face→ receives corticonuclear fib from both cerebral hemispheres
• Part of the nucleus that supplies lower part of the face → receives corticonuclear fib from opposite cerebral hemisphere.

   Parasympathetic nu-

• Superior salivatory nu
• Lacrimatory nu

BRANCHES OF FACIAL NERVE-

Tila – Temporal

Zhapun – Zygomatic

Bagha- Buccal

Mag- Mandibular

Cadel- Cervical

APPLIED ASPECTS-

SUPRANUCLEAR LESION-

Lower part of CL face inv

INFRANUCLEAR lesion-

• Whole of the face of IL side is paralysed
• Mouth drawn to nml side
• Wrinkles disappear from forehead
• Lagophthalmos
• Food accumulates in cheek during mastication
• Causes-

-Bell’s palsy

-Brainstem ddis

Acoustic neuroma

RAMSAY HUNT SYN-

• HZ inf of geniculate ganglion of VII n
• LMN VII N palsy
• Sev pain & vesicles in the ear.

   BELL’S PALSY-

• Idiopathic VII n palsy
• Viral prodrome
• Ear pain
• Facial numbness
• Decreased tearing
• Decreased taste

LEVEL OF LESION IN VII N PALSY-

• Brainstem→ VI n palsy

                          Absent corneal sensation [V n]

• At / above geniculate ganglion→ Poor tear prod.

                                                         i.e Greater petrosal N

                                                         affected

• Below geniculate ganglion→Altered taste sensation

                                                  i.e Chorda tympani N affected

Read wills-239

DUANE’S  RETRACTION SYN-case

Characterised by-

• Marked limitation of abduction
• Slight limitation of adduction
• Retraction of globe on adduction
• Narrowing of PF on adduction & widening on abduction

     AETIO-

• Paradoxical innervation of LR on adduction→ Co-contraction of LR & MR→ retraction of globe→ Narrowing of PF
• Theory of structural anomalies-fibrosis of LR or MR or both

Resulting in co-contraction of MR & LR

• Abnml synergistic innervation bet MR & SO & IO

Causing Innervational upshoot / downshoot on adduction

• Leash effect→ Tight LR→ Mechanical upshoot / downshoot
• F > M
• UL [LE]
• Sporadic

C/F-

• Limited adductn / abductn
• Add→ globe retraction
• PF narrows on add & widens on abd
• Eyeball in prim pos may be esotropic, exotropic or orthotropic
• Upshoot & downshoot-1. Mechanical- tight LR [leash effect]

                                            -2 Innervational-misinnervation of vert   

                                                Recti

• Abnml head posture
• Diplopia-rare
• Sensory adaptation- ARC & amblyopia

Asstd ocular anomalies-

• Anisometropia
• Optic n hypoplasia
• Morning glory syn
• Cong ptosis
• Nystagmus
• Cong cat
• Heterochromia iridis
• Persistent hyaloid a
• Choroidal coloboma
• Districhiasis
• Papillary anomalies
• Keratoconus
• Microphthamos

Systemic asstn

• klippel –feil syn
• goldenhar’s syn
• facial hemiatrophy
• spina bifida
• umbilical hernia
• polydactyly
• Chiari malformation
• Sensorineural hearing deficit
• Wilderwank syn
• Cervico-oculo-acoustic syn-Duane’s

                                               -sensorineural hearing def

                                               -Klippel feil anomaly of spine

    HUBER’S CLASS-

TYPE 1-

• Marked limitation of abduction
• Nml / slightly defective adduction
• Add→ globe retracts & PF narrows
• Abd→ PF widens

TYPE 2-

• Marked limitation of add
• Nml / slightly defective abd
• Add→ PF narrows & globe retracts

TYPE 3-

• Marked limitation of add & abd
• On add & abd→ globe retracts & PF narrows

T/T-SURGERY-

IND-

1. Eyes not in a prim pos
2. Abnml head posture
3. Upshoots /downshoots
4. Sev globe retraction

SURGERY-

1. For Face turn / Esotropia in Prim pos→MR recession of affected eye
2. LR resection shud be avoided as it increases globe retraction , upshoot & downshoot.
3. For upshoot & downshoot [leash effect]→ Faden’s oper
4. For upshoot / downshoot [innervational] → 3mm recession of vertical recti

                   BROWN’S SYN-case

DEF-

Apparent paralysis of IO ms d/t restriction of its action by an overly taut SO tendon of the same eye.

Also k/as- Superior oblique sheath syn

AETIO-

1. Congenitally taut SO tendon d/t shortened ant sheath of SO tendon.
2. Acquired- [TTRR]

1. Tenosynovitis of SO trochlear apparatus
2. Trauma to the trochlea
3. Rheumatoid nodules on SO tendon post to the trochlea
4. Retrotrochlear thickening of the tendon→impaired slippage of the tendon thru the trochlea.

C/F-

• Congenital- UL & constant
• Acqd- intermittent & improve spontaneously
• Elevation is limited in adduction & present in abduction.Overaction of SO is absent [ which shud be present in IO paresis]
• Divergence in upgaze-V –pattern-exotropia
• FDT is positive on attempts to elevate the adducted eye.
• An audible click may be heard on an attempt to elevate the adducted eye.

D/D-

1. IO paresis-SO overaction +nt

                    -FDT –ve

2.Double elevator palsy

3.  #  orbital floor

4.  Grave’s o’pathy

5.  Cong fibrosis of IR

T/T-

CONSERVATIVE T/T- For acqd cases which improve spontaneously

• Eye motility exercises
• Steroids- oral or inj in trochlea
• Correction of underlying cause

    SURGERY-

• SO tenotomy
• SO tenectomy-6mm done to avoid SO palsy
• SO weakening with a silicone expander.

SUPERIOR OBLIQUE OVERACTION[ j-02]-case

DEF- Characterised by downshoot of eye in adduction

AETIO-

1. Primary overaction of SO –mechanical or innervational

                                            -isolated or with esotropia/ e xotropia

2. Sec overaction of SO caused by paralysis / paresis of-

  Antagonist- IL –IO

 Yolk ms- CL- IR

	PRIMARY SO OVERACTION	SEC SO OVERACTION
1. Age	2-3 years	Any age
2. Bilateral	Frequently	Occasionally
3. Downshoot of adducted eye	+	+
4. Horizontal deviation	+	-
5.Vertical deviation	-	+
6.Head tilt	-	+ after 6 yrs of age
7. Incyclodeviation	+	+
8.FDT	+	+

Rx-

In a pt with clinically significant ocular dev or A-pattern,sec to BL SO overaction, BL SO weakening procedure is indicated.\

These are-

1) SO Tenotomy-

- can be performed nasal / temporal to SR

-Nasal gives more effect

2) SO lengthening –by insertion of a silicon expander or a non-absorbable suture

A-V PHENOMENON [J-01,D-01, D-03]

case

DEF-

Horizontal deviation that change in magnitude with upgaze & downgaze.

CLASS-

1. A-Pattern- Increase convergence in upgaze

                   -    “          divergence in downgaze

A- esotropia- esotropia increases upgaze

                   -       “        decreases in downgaze

1. Exotropia-Exotropia increases in downgaze

                    -      “         decreases in upgaze

2.V- Pattern- Increase divergence in upgaze

                   -       “       convergence in downgaze

V- Esotropia- Esotropia increases in downgaze

                     -       “         decreases in upgaze

 V- Exotropia- Exotropia increases in upgaze

                      -      “          decreases in downgaze

               

3.Y- pattern- Exotropia only in upgaze

4.λ- Pattern-Exotropia only in downgaze

5.X- Pattern- No / small dev in prim pos

                   -Exotropia in up & downgaze

AETIO-

1. Oblique ms dysfunction-

v-pattern→ IO overaction

A-pattern→ SO overaction

Factors responsible for oblique ms dysfunction-

• Innervational
• Disturbed parallelism of SO & IO
• Anamolous insertion of obl ms
• Ocular / orbital torsion

2.Horizontal ms dysfunction-

For me- A- underaction

             V-overaction

LR –overaction→ Exotropia

• Underaction→Esotropia

MR- overaction→ Esotropia

     -Underaction→ Exotropia

1. eso→LR underaction

A-exo→MR underaction

V-eso→MR Overaction

V-exo→ LR overaction

3. Orbital factors-

• Apert’s syn / Crouzon’s syn→V-eso/exo with marked elev of adducting eye
• Upward / downward slanting palp fissure may show A-V pattern

    C/F-

1. Diplopia
2. Asthenopia
3. Abnml head posture-

Esotropia-Chin moved towards apex  of A or V

             Exotropia-Chin moved away from apex of A or V

    

4. Sensory adaptation-

• ARC
• Strabismic amblyopia

   CLINICAL WORKUP-

1. Prism & alternate cover test
2. Von Noorden’s method of measurement of deviation-At 0 deg, 25 deg elev &35 deg dep
3. Diff in upgaze & downgaze-

V- pattern-15 PD / >

A-pattern-10 PD / >

4) Version test- For overaction & underaction of obl ms

5) Compensatory head posture

6) BSV

T/T-

IND-

1. Cosmetic

2. To reduce chin elev/ dep

3. To maintain, improve  & regain BSV

A) Without oblique ms dysfunction-

1) V-pattern- Eso→ BL MR Recession + Downward        

                                                                       Transposition of MR

                       -Exo→BL LR Recession + upward transposition of

                                                                       LR

   2) A-pattern-Eso→BL MR Recession + upward transposition of            

                                                                     MR

                       -Exo→BL LR Recession + downward trans of LR

Principles of transposition-

MALE- MR to apex

• LR to empty space

2. For IO overaction→ IO recession BL

           SO overaction→ SO tenotomy BL

         ACCOMODATIVE ESOTROPIA-case

Read from notes

DEF-Convergent deviation of the eyes varies with the amount of accommodation exerted.

TYPES-

1. Refractive acc eso
2. Non-Refractive Acc Eso
3. Hypoaccomodative Eso
4. Partially Acc Eso

    REFRACTIVE ACCOMODATIVE ESOTOPIA

• Manifests by 2-3 yrs of age
• Stages-

    A] Stage of intermittent Esotropia-

• Transient diplopia
• Irritability
• Closing of one eye

B] Stage of Constant Esotropia-

• Deviation is more at near than distance fixation
• Distance versus near deviation is usually within 10 PD
• HM ranges from 2-6 d
• AC / A ratio is nml

• Course of events in uncorrected high HM-                Uncorrected hyperpopia→ Blurred retinal image

A)→No effort to accommodate→Remain orthotropic but dev BL ametropic amblyopia.

B)→ Accommodate to clear the ret blur→Excessive accommodative convergence→

1. Insufficient fusional divergence & nml / high AC/A →Ref Acc Eso
2. Insufficient Fusional divergence→ Esophoria
3. Low / flat AC /A→ Orthotropia

CLINICAL EVALUATION & DIAGNOSES-

1. Measurement of deviation for far & near in all cardinal pos of gaze
2. Cycloplegic ref-

1 % Atropine E/O TDS for 3 consecutive days→ Complete cycloplegia + relaxed accomdn→ Child starts tolerating glasses

3.  Measurement of Fusional divergence amplitude

    NML- Distance- > 3PD

             -Near > 8 PD

4. Fundus exam-To rule out RB

T/T-

A] OPTICAL CORRECTION-

Full optical correction-

1. From birth – 6 mo-

• All infants with HM OF +2D or more shud be given glasses
• Prescription-Full r’scopic finding + Additional +1.5 D
• Additional +1.5 D provides clear vision upto 66cm which is the usual limit of the infant’s world
• FU-Every 2-3 wks

         -If esotropia persists → Repeat R’scopy-

        A] If additional HM → change the glasses

        B]  If no change→ Change the diag to infantile type

2. From 6mo-6yrs

• HM > +1.5D→ Full R’scopic finding WITHOUT any add plus lens
• FU-every mo
• Once stabilized under 1 year of age→Repeat R’scopy every 3mo
• 1-5 yrs→ Repeat R’scopy every 6 mo

3. > 6yrs-

• Minimum power lens ( which shud provide both BSV with esophoria & max V/A)
• FU-Every 6 mo for 2yrs ,then every year.

B]  AMBLYOPIA THERAPY-

IND-

When a child has been brought late with a constant UL Acc eso with amblyopia

-Give Full HM correction with occlusion therapy.

C]  ORTHOPTIC T/T-

-   Once the occlusion therapy improves V/A ,Orthoptic t/t aims at overcoming suppression & improving negative fusional convergence.

-Prerequisites-

1. Child shud hav worn glasses for sev wks
2. Amblyopia has been t/ted
3. Child is coop

• Antisuppresion exercises
• Exercises to improve Negative fusional convergence

 D] SURGERY-

       BL MR Recession

NON-REFRACTIVE ACCOMODATIVE ESOTROPIA

• High AC/A RATIO
• Esotropia is greater at near than distance fixation.
• Unrelated to ref error
• Near point of accommodation is nml for the age of the patient
• Principle factor responsible is an excessive amt of accom convergence with a nml amt of accomdn i.e high AC/A ratio
• Age 2-3 yrs

   CLINICAL EVALUATION-

1. Measurement of deviation by prism & alternate cover test
2. Cycloplegic refraction.

 Ref error- emmetropia, HM OR Myopia

3. Measurement of AC/A ratio by Heterophoria / Gradient method
4. Measurement of fusional divergence amplitude
5. Fundus

    T/T-

1] AMBLYOPIA THERAPY

2] BIFOCAL GLASSES-

*   Since near dev is the prim obstacle to nml BSV, a bifocal add of +3D over the full cycloplegic refraction with simultaneous orthoptic exercise is useful

*    All infants below 6 mo with definite esotropia shud be prescribed the full R’scopic finding + add of +1.5D as a single vision glass.

*    Bifocals are not reqd below 6 mo bcos V/A is limited to 66cm

*    Bifocals shud not be prescribed in the presence of amblyopia

The separation line bet distance & near segments shud bisect the pupil or touch its lower border wen the child looks straight→ k/as Executive glasses.

FU-

Every 3 mo upto 1 yr

Every 6mo upto 2yrs

Thereafter every year

Bifocals shud be continued till 5yrs after which it shud be weaned off in steps of +0.75to +1D.it shud be completely be weaned off by 10 yrs of age

3} MIOTICS-

*   Echothiophate iodide 0.125% OD or Pilocarpine 4% QID for 6wks

*miotics induce peripheral accommodation [ i.e direct stim of the ciliary ms rather than that mediated by the III N]

4] ORTHOPTICS

5] SURGERY- BL MR recession

HYPOACCOMODATIVE ESOTROPIA

• To overcome accom there is an increased accom effort → increased convergence→Near esotropia
• Esotropia is large for near fixation & small for distance fixation
• Not related to uncorrected HM
• AC/A not high
• Near point of accom is remote i.e weak accom

T/T-

1] bifocal glasses

2] Orthoptic exercises

PARTIALLY ACCOMODATIVE ESOTROPIA

• Partly d/t some accom & some non-accom factor
• 2 types-

1. Infantile esotropia with superadded accom esotropia-

Child first dev typical infantile esotropia before 6mo which is non-accom.This is superadded by accom esotropia by 2-3 yrs + larger HM

2. Decompensated accom esotropia + Superadded non-accom esotropia-

Accom esotropia is well-corrected with glasses / bifocal lenses but after some time eso again dev either d/t increase convergence tone or mechanical factors like hypertrophy or contracture of MR , conj or tenon’s cap

T/T-

1] Correction of accom part of esotropia

2] Amblyopia t/t before surg

3]Surgery-Only accom part needs to be corrected

  BL MR recession

ESSENTIAL INFANTILE ESOTROPIA

• First 6 mo of life
• Otherwise nml infant
• No ref error
• No restriction of OM
• Angle is large [30PD]
• Fixation is alternating in prim pos & cross-fixating in side-gaze [D/D –BL 6th N palsy]
• Horizontal nystagmus
• Rx- Initial mgt-

BL MR recession  by 12mo of age [after correction of amblyopia & significant ref error]

Subsequent mgt-

1.If undercorrection-Furthar MR recession or resection of one / both the LR

2. For IO overaction [may dev by 2yrs]-IO weakening

3. DVD- SR recession +/- faden’s

           -IO anterior transposition

4 Amblyopia Rx

                 MICROTROPIA-notes

• may be -primary or may follow surg for a large deviation
• Anisometropia
• Very small angle- 8PD
• Central suppression scotoma-detected by Bagolini’s striated glasses & 4prism base out test
• Rx- 1. Spect- anisometropia

          2. Occlusion- amblyopia

                              AMBLYOPIA-case

DEF-

UL / BL decrease of best corrected V/A caused by form vision deprivation & / or abnml binocular interaction, for which there is no pathology of the eye or visual pathway

CLASS/ CAUSES-

1. STRABISMIC AMBLYOPIA-

• MC
• UL constant squint→ one eye is used for fixation
• Always UL
• MC in esotropes
• Very rare in hyperopia

2. STIMULUS DEPRIVATION AMBLYOPIA-

• Least common but most damaging & diff to treat
• UL cong / traumatic cat
• Cor opacity
• Complete ptosis
• VH
• Prolonged patching of one eye

3. ANISOMETROPIC AMBLYOPIA-

• 2nd MC
• UL High ref error
• MC- Hyperopia

4. ISOAMETROPIC AMBLYOPIA-

• BL uncorrected high ref error
• Hyperopia- > + 5D
• Myopia- > -10D
• MC- Hyperopes

5. MERIDIONAL AMBLYOPIA-

• Uncorrected astigmatism

6. IDIOPATHIC AMBLYOPIA-

• No squint
• No amblyogenic factor

7. AMBLYOPIA SEC TO NYSTAGMUS-

8)TOXIC AMBLYOPIA-

*  Tobacco

*  Ethyl alcohol

*  Quinine

9. HYSTERICAL AMBLYOPIA

T/T-

EVALUATION-

1. V/A
2. Neutral density filter test

-BCVA taken

-Filter placed in front of the amb eye & V/A taken

-No drop in V/A → amblyopia

-Significant drop→ org cause

3. Test for crowding phen-V/A is better while reading single letter rather a row of letters
4. Thorough ocular exam + fundus
5. Refraction
6. central vs eccentric fixation
7. test for sensory anomalies

RX-

     1Occlusion

2.Penalisation

3.CAM vision stimulator

4. Pleoptics
5. Drugs

1 . OCCLUSION THERAPY-

A)  - Direct→ Patch the sound eye

     -Inverse→ Patch the amblyopic eye [not recommended]

2. - Total→ All light prevented-Gauze & pad

                                                   -Doynes rubber occluder

                                                   -Elastoplast

     -Partial→ Does not cut off total light-Scotch tape

                                                                 -Nailpaint

                                                                 -Cellophane

C) –Constant[ Full-time]-Morn-night

    -Intermittent [Part time]-Close work  & TV

Scheme-

1. Initial mgt-Direct ,full time & total occlusion+ Inverse to prevent occlusion amb

SCHEDULE-

AGE[ YRS ]	PERIOD –D : I	FOLLOW-UP
Upto 2	2:1	15 days
3	3:1	15 days
4	4:1	30 days
5	5:1	30 days
> 6	6:1	30 days

If no imp upto 3 mo→Suspect organic dis & recheck refraction

Incomplete response→ Anisohypermetropia

                                → Anisoastigmatism

2. Maintenance t/t-

• Ct occlusion till 9 yrs of age
• Part time occln + Active vision exercises

COMPLICATIONS-

1. Occlusion amblyopia

2 .Eccentric fixation

3.Occlusion esotropia

4.Recurrence of amblyopia

2)PENALISATION-

• Means –To punish
• Principle- Penalize the sound eye for dist, near & both & force the amb eye to greater use for dist, near & both.
• Done with- cycloplegics & Glasses
• Ind-

1. Mild deg of amblyopia  [V/A-6/12p]
2. Maintaining vision obtained thru occlusion
3. Pre-requisite- Eyes shud be straight, so used in anisometropic amblyopia without deviation

METHODS-

1. Near penalization
2. Distance penalization
3. Total penalization

NEAR PENALIZATION-

• Fixing eye → Atropinized + Fully corrected for distance
• Amblyopic eye→overcorrected with +2 to +3D
• Thus amb eye is forced to be used in near vision Stim alteration of two eyes for near & distance
• OR Sound eye-Atropine & Amb eye-pilocarpine
• This produces a PH effect[ d/t pupil constriction]→ improves near fixation [d/t facilitation of accommodation]

DISTANCE PENALIZATION-

• Fixing eye→ Atropinized + overcorrected by + 3D→ used for near
• Amb eye →Fully corrected for distance
• Thus sound eye is penalized for distance & used only for near & amb eye used for dist

TOTAL PENALIZATION-

• Fixing eye→ atropinized & undercorrected by 4 to 5D
• Amb eye → Fully corrected
• Prevents sound eye from use in near & dist

3. CAM VISION STIMULATOR-

• CAM stands for Cambridge [England] where this device was first used
• Method-

• Occlude the sound eye.
• Stim the amb eye for 7 min by slowly rotating high contrast square wave gratings of diff spatial freq
• Once a wk for 3-4 wks

• Principle- Rotating grating→specific stim for cortical neurons
• Used as supplementary to occlusion therapy

4. PLEOPTICS-

• Greek word- Full vision
• Active stim of fovea→ overcomes eccentric fixation→ increases V/A
• Peripheral ret including the eccentrically fixing area around the fovea is dazzled with an intense light while protecting foveal area
• Ind-only wen occlusion fails.

5. DRUGS

• L-Dopa Benserazid

                              BOTULINUM TOXIN[ J-03,02]

• Antigen specific neurotoxin produced by clostridium botulinum
• Onset of act- 24-72 hrs
• MOA- B→ blocks the release of acetylcholine→chemical denervation→Paralysis of ms→ Antagonist ms becomes comparatively stronger & thus neutralizes the deviation
• IND-

1. Congenital esotropia
2. Cranial N palsies
3. Entropion
4. Blepharospasm
5. Nystagmus
6. Grave’s ophthalmopathy
7. Facial wrinkles

• DOSE-

• Stored in a frozen lyophilized form
• Reconstitued with NS
• Shud be used within 4 hrs
• Easily degraded by vigorous shaking, rapid inj or changes in PH & TEMP
• 2.5 units per muscle has been recommended
• Lethal dose- 40 U /kg body wt

• COMPLICATIONS-

1. Ptosis
2. Diplopia
3. Globe perforation
4. Retrobulbar / subconj h’age
5. Dry eye
6. keratitis
7. Lid retraction
8. Punctal eversion

                          SQUINT  SURGERY

NOTES

1. WEAKENING PROCEDURES-

1. Recession
2. Marginal myotomy
3. Myectomy
4. Faden’s posterior fixation suture

2. STRENGTHENING PROCEDURES-

1. Resection
2. Advancement
3. Double breasting or Tucking
4. Cinching
5. Transpositin of adjacent ms

1. WEAKENING PROCEDURES-

1. RECESSION-

• Rectus / oblique ms is disinserted & reinserted to a point closer to its origin.
• This changes the arc of contact of the ms with the globe→ slackens the ms
• Max limits of recession-

        MR→ 6mm

        LR→8mm

Small child- MR-5.5mm & LR-7mm

• Min limit-

         MR→3mm

         LR→4mm

NON-ADJUSTABLE RECESSION SURGERY-

A.HANGBACK RECESSION-

Ms is recessed & suspended with sutures placed at the original stump.

Indicated in supermax recession

B. HEMIHANGBACK RECESSION-

Ms is recessed & suspended with sutures placed halfway behind the original insertion

ADJUSTABLE RECESSION SURGERY-

• Has the ability to modify the pos of a newly operated ms by the use of adjustable sutures
• Amt of recession is allowed wen the effect of anaesthesia has worn off but before healing has commenced
• IND-

1. Vertical deviations in TED
2. Blow out # -floor of orbit
3. VI n palsy
4. Adult Exotropia

• C/I- Young & uncooperative pt

2. MARGINAL MYOTOMY-

• Incision is given partly thru the ms thereby weakening it.
• Number of contractile fib are reduced.

3.MYECTOMY-

Obsolete

4.FADEN’S POSTERIOR FIXATION SUTURE-

*   Weakens the ms only  in its field of  action

*    Does not affect deviation in the prim pos.

*    Ms insertion is shifted posteriorly

*    Most effective on MR & least on LR

*     IND-

1.  DVD

2.Nystagmus Blockage syn

3.Paralytic sq

4.Duane’s retraction sy

STRENGTHENING PROCEDURES-

1. RESECTION-

• Implies excision of the tendinous part of the ms only
• Shortens the ms length→ makes the ms taut
• Max limit-

MR→ 6mm

LR→9mm

• Min limit

MR→3mm

LR→ 4.5mm

2.ADVANCEMENT-

*   Ms is re-inserted closer to the limbus→ stretching the ms

*   Reverse of recession

*   Ideal choice in a consecutive squint where a recession has been done earlier

3.DOUBLE BREASTING / TUCKING-

• Ms is shortened without excising the ms mass
• Achieved by double –breasting the tendinous / muscular part
• Not preferred for recti
• SO tucking is common

4.CINCHING-

*   Modified double breasting

*   In these two procedures ms is not disinserted& ant ciliary Vs are not compromised, thusnot risking ant seg ischaemia.

5. TRANSPOSITION PROCEDURES-

• Jensen’S proc
• Hummelsheim’s proc
• [already described]

COMPLICATIONS-

1. INTRAOPERATIVE-

1. SURGICAL-

1. H’age- during-Conj incision

                          -ms disinsertion

2.   Scleral perforation-during-Conj incision

                                               -Ms disinsertion

                                               -Passing suture

3.   Splitting of ms fibre- d/t faulty hooking tech

4.   Loose suture& partial thickness suture in the ms

5.   Lost ms / slipped ms during disinsertion, without the sutures having passed or sutures hav given way

6.    Rupture of ms & tenon’s capsule→ fat prolapse

2. ANAESTHESIA RELATED-

1. Cardiac arrest
2. Bradycardia
3. Malignant hypertension
4. Allergy

2. POST-OPERATIVE-

1. vomiting
2. Infection
3. Suture granuloma
4. Tenon’s prolapse & conj cyst
5. Dellen- d/t disruption of tear film
6. Ant segment ischaemia
7. Overcorrection & undercorrection