phacoemulsification in myopic eyes

PHACOEMULSIFICATION IN MYOPIC EYES

Sumeet AgrawalPG 3

UCMS and GTB HospitalDelhi

HOW IS IT DIFFERENT FROM A ROUTINE CATARACT SURGERY ?

PREOPERATIVE

INTRAOPERATIVE

POSTOPERATIVE

WHEN TO BE CONCERNED ?

• Degree of myopia– High myopia (2%)• ( Spherical equivalent -6.00 D or more; Axial length 26.5

mm or more)

– Pathological myopia (0.5%)• ( Spherical equivalent -8.00 D or more; Axial length 32.5

or more)

UNILATERAL / BILATERALKeep the possibility of amblyopia, specially if unilateral

Visual acuity before onset of cataractHistory of spectacle use; History of trauma

PATIENT EXPECTATIONS (informed consent)Use of reading glasses

Refractive surprises

CENTRAL FUNDUS EVALUATION*Macular scar* *Forster Fuch’s spot* *Myopic degeneration* *Epiretinal membrane*

*CNV* *Posterior staphyloma*

Careful INDIRECT OPHTHALMOSCOPY to look for retinal breaks

Zonular weakness

IOL POWER CALCULATION*Axial length pitfalls* *SRK II / SRK-T / Holladay 2 formula*

*Aim for postop residual myopia*

INTRAOPERATIVE CONSIDERATIONS

• Peribulbar / Retrobulbar block : chances of globe perforation ; topical / subtenon anaesthesia

• Clear corneal incisions with a short tunnel– Limbal / scleral incisions heal poorly due to low scleral

rigidity– Suture if in doubt

• High elasticity of anterior capsule

• Deep AC – Difficult instrumentation– Stretching of iris - > pain (intracameral lignocaine)– Reverse pupillary block (Lens-Iris-Diaphragm

Retrodisplacement Syndrome (LIDRS))– (Low bottle height with low vacuum)

• Avoid traction to vitreous base– Abrupt collapse of anterior chamber– Inject viscoelastic before removing probe

• Posterior capulorrhexis (to avoid future need for YAG capsulotomy); controversial

• IOL – To implant or not

– Abbott Medical Optics Sensar AR40M acrylic IOL (as low as –10 D)

– Alcon AcrySof acrylic IOL (as low as –5 D)– Bausch & Lomb Crystalens AO (as low as +4 D) – Hoya Surgical Optics iSymm (as low as +6 D)

– Avoid silicon IOLs

POSTOPERATIVE

• Refraction takes longer to stabilize

• Check for retinal breaks

• Closer and more frequent follow ups

• Operate the other eye earlier if high anisometropia

THANK YOU