**2.5 Anesthesia**

*Retinoblastoma - Past, Present and Future*

*2.3.3 Ophthalmic ultrasound*

child is large enough or a portable slit lamp is available, slit lamp examination should be performed, care to note, presence or absence of cataract, conjunctival or scleral injection, anterior segment shallowing, neovascularization of the iris, iris seeding or iris atrophy. Evaluate for retrolental membranes to assess presence of retinopathy of prematurity or persistent fetal vasculature. Most patients with retinoblastoma have normal anterior segments but may have anterior cells or nodules on the iris. In exophytic tumors, visualization of retinal vasculature behind the lens may be possible as well. Indirect ophthalmoscopy should be performed to evaluate the posterior pole and fundus. Depending on the age of the child, they may cooperate or family members may be needed to help secure the patient in a supine position. Very young children may be swaddled with a blanket to secure their limbs. The indirect exam in the office should be used to rule out simulating lesions when possible and to also increase or decrease suspicion for retinoblastoma, thus determining whether examination under anesthesia (EUA) is needed for full evaluation and diagnosis. An eyelid speculum may be needed for proper dilated examination, and a topical anesthetic such as 0.5 or 1% proparacaine should be instilled prior to speculum insertion. Scleral depression may be indicated, if it can be reserved for examination

under anesthesia it is less traumatic but can be done in the office setting.

be taken as a baseline to compare to in the future following treatment.

*2.4 Exam under anesthesia (EUA) considerations*

An ophthalmic ultrasound can be performed in the A and B scan mode using a 10 mHz transducer to evaluate for intraocular masses, retinal detachment, or calcification. In retinoblastoma, the ultrasound should reveal an irregular mass, which is more echogenic than the vitreous, and commonly has fine calcifications (highly reflective foci mostly with acoustic shadowing) since upon histologic study, 95% of retinoblastoma contains calcification [14] (**Figure 1**). Measurements should

If EUA is warranted, general anesthesia will be needed to conduct detailed examination and ancillary testing at one time. Preparation of the room for EUA should consist of examination materials including: external photography, portable slit lamp, tonometry, indirect ophthalmoscope with condensing lens and scleral

*10 mHz ultrasound in A and B scan mode showing a large intraocular retinoblastoma with irregular mass and* 

**30**

**Figure 1.**

*intrinsic calcification with acoustic shadowing.*

The type of general anesthetic and airway support varies depending on institution and available resources. Safe anesthesia methods range from mask anesthesia, to laryngeal mask airway (LMA), to complete endotracheal intubation. Both inhaled anesthetics and intravenous anesthetics, or a combination of the two, are suitable for examination. General guidelines recommend that heavy fatty meals be discontinued 8 h prior to procedure, light meals, formula, and nonhuman milk 6 h prior to surgery, human milk 4 h prior to anesthesia, and clear liquids 2 h prior to anesthesia [15]. These recommendations will vary by location and anesthesiologist, and type of anesthesia administered. Recently there has been literature support for use of LMA without placement of intravenous lines, which reduces total time under anesthesia without increased anesthesia complications, all of which were managed successfully without long term sequelae [16].
