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Preserve edges/flaps: not even small pieces of corneal tissue should be excised since this leads to flattening and astigmatism due to the suture requiring extreme tightness to achieve watertightness; the "missing" piece is commonly found folded under

Suture removal

6-8 weeks in children; 2-6 months in adults3

2 One alternative to permanent suturing is to temporarily cover the corneal wound with conjunctiva; this can reduce the ECH risk, and prevent infection and iatrogenic damage by improper corneal suturing.

3 Also influenced by other factors: speed of wound healing; length and location of the wound; irritation from the suture

• Whether and how long a patch and/or shield is used depends on wound characteristics, wound healing characteristics, patient compliance, and patient preference.

Table 2.2.5 Basic principles of suture introduction for corneal wounds

Variable

Comment

Type of suture

Running or interrupted (Fig. 2.2.4)

Material of suture

Nylon, 10-0 or 11-0

Bite length

Should be identical on both sides, unless the wound is oblique (shelved; Fig. 2.2.9)

No. of sutures

Determined by the length of the wound and the length of the sutures bites, the spacing, and the tension put on the sutures (Fig. 2.2.2)

Order of sutures placement

If landmarks such as the limbus or an angle in the wound are present, these should be closed first (Figs. 2.2.5b, 2.2.10); if the wound is limbus to limbus and crosses much of the cornea, suturing should start from the outsides and continue inwards; otherwise, the 50% rule is generally applied (Fig. 2.2.5d)

Forceps use

There is no need to grab the cornea with forceps. The spatula needles used today are sharp enough to easily perforate the cornea.4 If counterforce is needed when the needle engages the cornea (entry), the adjacent conjunctiva should be grabbed.5 If counter pressure is needed when the needle enters the cornea from the AC (exit), this can be achieved by pressing down on the corneal surface with the arms6 of the forceps, which is held slightly opened; the needle should exit the cornea between the two arms of the forceps

4 A spatula needle of approximately 6 mm in length and 3/8 in. circle is recommended; the wire diameter is approximately 0.15 mm.

5 Always on the side where the needle enters the cornea, not on the opposite side, even if the conjunctiva in that location appears more convenient to grab

6 Not by grabbing the cornea with the working tip of the forceps; this eliminates causing additional corneal damage

Table 2.2.5 (continued) Basic principles of suture introduction for corneal wounds

Variable

Comment

Depth of sutures

Full thickness (Fig. 2.2.6b)

Angle/direction of the needle

At 90°, unless a single running suture is used (Figs. 2.2.2, and 2.2.4)

Knot creation and handling

The knot should be small enough to be easily buried but strong enough to prevent release or loosening. The ideal knot has three throws: the first is a triple one, tightened after the surgeon crossed his/her hands (Fig. 2.2.7). Tightening is perpendicular to the wound's plane; the second throw is a single one

and tightened parallel to the wound's plane (i.e., perpendicular to the initial tightening plane); the third throw is also a single one and tightening is perpendicular to the wound's plane. All knots must be buried since they can cause severe inflammation/ irritation. The knot can be turned in either direction as the suture channels are, and their directions should be, identical on the two sides7

7 If the cornea is very edematous, it may be difficult to bury the knot; in such cases, a flat-faced forceps can be used to "compress" the knot first. Such a maneuver usually allows the knot to easily slip into the channel - this extremely useful pearl is the idea of the author's head OR nurse, N. Rudolf.

Table 2.2.6 Pro- and contra arguments regarding the use of full-thickness corneal sutures

Don't use full-thickness sutures because...

The risk of endophthalmitis is increased: a channel is established between the extraocular space and the AC

Full-thickness sutures can safely be used because.

The channel cut by the needle (A) is not much larger than the cross-section of the thread (B); the channel is rapidly closed as the surrounding cornea's edema compresses it (C). As soon as a few minutes after suture introduction, pressure on the eye is unable to produce aqueous leakage from the AC through the suture channel8

The thread pressed against the

The thread pressed against the en-

endothelium causes cell death

dothelium probably indeed causes

and leads to increased edema

cell death in that very tiny area;

formation

however, by immediately blocking

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