Fig. 9.13  (a) Recurrent retinoblastoma within a previous cryotherapy scar, visualized with scleral depression and RetCam® imaging. A posterior 532 nm laser barrier line is seen posterior

to the scar, placed to decrease the risk of serous effusion spreading posteriorly. (b–d) The first freeze of triple freeze–thaw cryotherapy

−−A laser barrier line posterior to the superior located tumors is advisable before cryotherapy, to limit possible serous effusion and retinal detachment after the acute freeze (Fig. 9.13a).

−−Although laser is preferable to cryotherapy for posterior lesions, the “cutting-cryo” technique may be used to treat certain posterior lesions. A small opening is made in the conjunctiva to allow the probe better access to the lesion, of course avoiding the optic nerve and macula [41].

−−Prechemo-cryotherapy increases chemotherapy concentrations within the vitreous especially in the presence of cyclosporine [40]. It is indicated for eyes without retinal detachment less than 48 h before chemotherapy for IIRC Group D tumors, vitreous seeds, and in some recurrences. The technique consists of single-freeze cryotherapy to the peripheral healthy retina in the vicinity of the vitreous seeds or tumor mass.

9.11.6  Consequences

•Inadequate cryotherapy will fail to control the retinoblastoma.

•Overly aggressive cryotherapy may cause ocular complications of hemorrhage or retinal detachment.

•Cryotherapy is not recommended if retina is detached.

•Cryotherapy adjacent to calcified regressed tumors may create breaks in the retina.

•Cryotherapy must be applied carefully in postradiation and postplaque therapy, because the retinal vessels may be particularly fragile and bleed.

9.11.7  Related SOPs

OPHTH cryotherapy; OPHTH RetCam®; OPHTH prechemo­ -cryotherapy.

9.12  Laser Therapy SOP

9.12.1  Objective

Physical ablation of small retinoblastoma.

9.12.2  Applicability

Ophthalmologist.