Ординатура / Офтальмология / Английские материалы / Moorfields Manual of Ophthalmology_Jackson_2007

Appendix 5

Ophthalmic Surgical Instruments

Forceps Ophthalmic forceps have three parts: tip, shaft, and handle. The term ‘platform’ refers to the last 5–7 mm of the shaft and includes the tip. There are three main types:

■Toothed : for holding tissues.

■Notched : also used for holding tissues but causes less trauma.

■Tying : for holding and tying sutures. Most are designed to

close incrementally with increasing pressure.

Colibri forceps incorporate two types by adding a tying platform to the toothed forceps. The shaft can be straight, angled or curved. Commonly used ophthalmic forceps include (Fig. A5.1):

Fig. A5.1: Miscellaneous commonly used instruments.

Appendix 6

Use of the Operating Microscope

Modern operating microscopes have several important attributes including coaxial illumination, stereo-optics, fully adjustable eyepieces, and foot-controlled zoom and focusing.

The important steps in using the microscope are:

■Before surgery

1.Set the eyepiece interpupillary distance and move the observer’s viewing system to the correct side (left or right).

2.If wearing spectacles during surgery, ensure the eyepiece focus is set to zero and that the ‘spacers’ (adjustable pads that separate your eye from the eyepiece) are out.

3.If not wearing spectacles, set the eyepiece focus to your refraction and put in the spacers so you can rest your eyebrow on them during surgery.

4.Reset the microscope focus and XY to the centre of their travel (look for a Reset or Centre button).

5.Ensure the patient is comfortably positioned under the microscope.

6.Adjust the surgeon’s chair as required.

7.Scrub, prep, and drape.

■At the start of surgery

1.Adjust the position of the table, foot controls, microscope height, and importantly the eyepiece tilt so that your lower spine is straight or slightly extended, but never flexed.

2.When comfortable, set any wheel locks on the surgeon’s chair or mobile microscopes.

■During surgery

1.Most microscopes are parfocal; that is, the focus and zoom are independent.

2.However, increasing magnification reduces the depth of focus and may blur the image if the focal plane is far from

Appendix 7

Ophthalmic Drug Use in Pregnancy

Systemic absorption of topical eye medication may occur through conjunctival vessels or nasal mucosa. The latter is more common with drops than ointment. Systemic absorption may be reduced by nasolacrimal occlusion or eyelid closure for a few minutes after instillation, by avoiding the instillation of different drops in succession (since this increases the percentage of drops entering the nose and hence systemic absorption), and by blowing the nose after drop instillation into the eye. However, the amount of systemic absorption remains highly variable. In all categories of drug risk, any medication is advised to be used only when the benefit to the mother outweighs the risk to the fetus. Drugs should be prescribed using the lowest concentration at the minimum effective dose for the shortest duration of time to have their desired effect. For some drugs, there is conflicting data for their use and in many instances the toxicity advice refers to systemic and not topical use. Absence of a drug from Table A7.1 does not imply safety. Do not rely solely on the table, as the potential fetotoxic effects of topical ocular drugs are often uncertain, and the recommendations for systemic administration may not apply. If possible, avoid drugs in the first trimester. In each therapeutic group in the table, the drugs listed are those that are customarily used in ophthalmology in the UK.

Drug classification

■Category 1 Animal studies imply a low risk in pregnancy or the constituents of the medication are individually known to be of low risk. Also included in this category are drugs where the dose administered is so low that the systemic concentration is negligible.

■Category 2 Animal studies have shown adverse effects on the fetus, but there is some data for safety of use in human pregnancy. This group is further subdivided into A (lower-risk) and B (higher-risk) drugs. Lower-risk drugs include those drugs where there has been established experience with their systemic use in human pregnancy and therefore it can be

extrapolated that their topical use is associated with lower 702 risk. The higher-risk group includes drugs in which data