A giant tear develops in the same way but is deÞned as one of at least 3 clock hours in length. Its signiÞcance lies in the different surgical technique required to treat it10 and its increased PVR risk.

54.1.2 RD Due to a Dialysis

Seen most commonly after contusion, the retina is torn at the ora serrata where it is inseparable from the vitreous. The vitreous gel may appear healthy initially, but with time, it starts to degenerate, slowly detaching the adherent retina as the dynamic traction grows.

54.1.3 RD Due to a Round Hole

In at least half of the cases there is marked, visible VR traction.11 Even in the remaining cases, no RD is expected unless traction develops12 Ð this is often recognized by the patient as ßashes Ð or the RPE pump is deÞcient (see Sect. 26.3.1).

54.1.4 RD Due to a Staphyloma

Typically, this is a nonrhegmatogenous detachment13 (see Chap. 56).

54.2Additional Information About RD

Any ophthalmologist but especially the VR surgeon should keep in mind the following during the decision-making process.

54.2.1 History

¥The typical Ð and the only one that is pathognomic Ð complaint is that of a curtain, due to the visual-Þeld loss corresponding to the quadrant that has detached.

¥Loss of the entire visual field suddenly occurs if a VH accompanies the tearing of the retina. ~20% of RDs are accompanied by VH.

¥Flashes are spontaneously communicated by relatively few patients, although often conÞrmed by them when asked (see below). The ßashes are caused by dynamic VR traction (see below), whether as part of a PVD or not.14

¥The small ßoater that is occasionally described by the patient is rarely the operculum; it is usually a small hemorrhage or simply a vitreous opacity.

10The central edge of the retinal break is curled or inverted; there may also be vitreous behind the retina.

11The hole is inside or at the border of lattice degeneration.

12As mentioned before, dynamic traction is present once the vitreous loses its normal gel structure.

13Even if a macular hole is present, it is typically the consequence, not the cause, of the RD.

14The seeing of light (phosphene) is the only response the retina has, regardless of what kind the stimulus is.

¥~10% of the patients have bilateral RD, but only 20% of these occur simultaneously. These are the numbers that justify treating the fellow eye prophylactically (see below, Sect. 54.2.4.2).

54.2.2 Examination15

¥Even before the ophthalmologist looks at the retina, the presence of pigment clumps in the anterior vitreous (see Fig. 53.1) should raise the possibility of a retinal break, even an RD.

¥In a fresh RD, the retina can be very bullous and its surface rather smooth; however, it may be folded, too. The latter gives the false appearance of subretinal strands. Even intraoperatively, the distinction, at least until the surgeon touches the retina with an instrument, may be very difÞcult (see Sect. 32.4.1).

¥Chronic RDs are recognized by the presence of the following:16

ÐHigh-water marks: lines of pigmentation, signaling the temporary stoppage of the progression of the detachment in the past.

ÐIntraretinal cysts.

ÐCalcium oxalate crystals in the posterior pole.17

ÐMultiple breaks, present in ~40% of eyes.

ÐThe IOP is characteristically low, due to increased uveal outßow.

ÐRetinal thinning Ð resembling retinoschisis.18

¥The conÞguration of the RD suggests the location of the break (see Fig. 54.4).

54.2.3 Clinical Course

Faster progression is expected in the following cases:

¥Superior break (the effect of gravity19).

¥Large break (more traction, increased amount of incoming ßuid).

¥Vitreous gel that has massive structural breakdown (more traction).

¥Vitrectomized eye (no gel tamponading the retina).

¥Poor efÞcacy of the RPE pump and the IPM (reduced ßuid outßow and retinal adhesion).20

¥Lack of strong chorioretinal adhesions (e.g., scars Þxating the retina).

Occasionally the RD progression stops spontaneously. It is, however, much more common for the RD to not just progress but lead, if untreated, to PVR development (see Chap. 53).

15Only selected, less commonly discussed signs are mentioned here.

16Obviously, not all will be found in a single eye.

17These are small, yellowish dots intraand subretinally, signaling degeneration of the retina.

18In a fresh RD the retina is thickened, due to the edema.

19This is the most important element. The more superior the break, the faster the RD becomes total; in theory, a break at 12 oÕclock is the worst.

20These are largely unknown factors.