Intravitreal injection of ganciclovir for treatment of CMV retinitis

Key Landmarks & Anatomy for safely performing injections Limbus – the juncture of the cornea and sclera Pars plana – the safe area to penetrate the wall of the eye with a needle, 4 mm from the limbus Posterior ciliary vessels/nerves – the horizontal, 3/9 o’clock meridiens, the area to avoid when performing an injection

LIMBUS

limbus Limbus: border between the sclera and cornea

PARS PLANA

When looking at the outside of the eye – where are the internal structures? 6mm Zone of ciliary muscles 2.5mm End of retinal tissue (ora serrata) Pars Plana 4mm - Safe distance from the limbus

View from inside the eye Iris Ciliary Muscle zone (pars plicata) 2.5 mm 4 mm Pars plana Safe injection line 6 mm End of retinal tissue (ora serrata)

Ciliary body & pars plana summary iris Ciliary processes. Fibers (zonule) attach from these to the lens 4.0 mm Ciliary muscle contracts to change the shape of the lens and focus at near intraocular injections are safely performed thru the pars plana, avoiding the retina

IDENTIFYING THE INJECTION SITE

Posterior ciliary arteries and nerves There are 2 long posterior ciliary arteries and nerves, located temporally and nasally, starting in the mid-periphery, in the horizontal meridian When examining the inside of the eye with the Indirect Ophthalmoscope, these are sometimes visible landmarks for 3 and 9 o‘clock meridian

12 Retinal vessels Fovea Optic nerve 9 3 Long ciliary nerve Retinal vessels Vortex veins 6

Preferred injection site - OD 12 9 3 7 6

Preferred injection site - OS 12 9 3 4 6

Directing gaze: have the patient keep both eyes open, and give a target to look at

Measuring with the calipers 2 mm 4 mm

Measuring with the calipers

Injection approach 4mm from limbus Perpendicular approach Towards center of eye or optic nerve (to avoid lens)

Injection example

Equipment Topical anesthetic proparacaine 0.5% or oxybuprocaine 0.4% 5% Betadine solution Sterile cotton applicators 1ml syringe 30g needle if available, 27g or even 25g acceptable

Equipment (cont’d) Standard calipers or tip of 1ml TB syringe (without needle) Eyelid Speculum Ganciclovir solution (50 mg/ml) Mask and gloves

Preparation and dose Dilute 500mg vial of lyopholized ganciclovir with 10 ml sterile preservative free water, giving a solution of 50mg/ml Draw 0.1ml into syringe and flush back to make sure all air bubble are out, and syringe contains meds Injection dose is 0.05ml of ganciclovir solution: 2.5mg dose of ganciclovir Secure bottle of ganciclovir for future injections

Preparation and dose Ganciclovir 50mg/ml 500mg vial of lyopholized Sterile water 500mg vial of lyopholized ganciclovir Ganciclovir 50mg/ml

Work with an assistant

Prepare everything you will need BEFORE you touch the patient

Intraocular injection is not difficult BUT It is a surgical procedure and must be done with exact care if performed incorrectly, you can blind the patient Devote 100% attention always