Traumatic Breaks

Blunt or penetrating eye trauma can cause retinal breaks by direct retinal perforation, contusion, or vitreous traction. Fibrocellular proliferation occurring later at the site of an injury may cause vitreoretinal traction and subsequent detachment. Also see Chapter 18 in this volume.

Blunt trauma can cause retinal breaks by direct contusive injury to the globe through 2 mechanisms: (1) coup, adjacent to the point of trauma, and (2) contrecoup, opposite the point of trauma. Blunt trauma compresses the eye along its anteroposterior axis and expands it in the equatorial plane. Because the vitreous body is viscoelastic, slow compression of the eye has no deleterious effect on the retina. However, rapid compression of the eye results in severe traction on the vitreous base that may tear the retina.

Contusion injury may cause large, ragged equatorial breaks, dialysis, or a macular hole. Traumatic breaks are often multiple, and they are commonly found in the inferotemporal and superonasal quadrants. The most common injuries are dialyses, which may be as small as 1 ora bay (the distance between 2 retinal dentate processes at the latitude of the ora serrata) or may extend 90° or more. Dialyses are usually located at the posterior border of the vitreous base but can also occur at the anterior border (Fig 16-11; Activity 16-1). Avulsion of the vitreous base may be associated with dialysis and is considered pathognomonic of ocular contusion. The vitreous base can be avulsed from the underlying retina and nonpigmented epithelium of the pars plana without tearing either one; generally, however, one or both are also torn in the process. Less common types of breaks caused by blunt trauma are horseshoe-shaped tears (which may occur at the posterior margin of the vitreous base, at the posterior end of a meridional fold, or at the equator) and operculated holes.

Figure 16-11 Schematic illustration of retinal tears and holes. Part 1, Retinal breaks at borders of the vitreous base. A, Avulsion of vitreous base that lies free in the vitreous cavity. B, Dialysis of the ora serrata. C, Retinal tear at the posterior border of the vitreous base. D, Retinal tear at the anterior border of the vitreous base. Part 2, Retinal breaks with areas of abnormal vitreoretinal interface (lattice degeneration). E, Lattice degeneration with holes. F, Round holes in atrophic retina. Part 3, Retinal breaks associated with abnormal vitreoretinal attachments. G, Horseshoe-shaped tear at the posterior end of a meridional fold. H, Horseshoe-shaped tear in the equatorial zone. I, Tear with operculum in the overlying vitreous. J, Horseshoeshaped tear associated with an anomalous posterior extension of the vitreous base.

(Illustration by Mark M. Miller.)

Courtesy of Mark M. Miller and Colin McCannel, MD.

Access all Section 12 activities at www.aao.org/bcscactivity_section12.

Excerpted from BCSC 2020-2021 series: Section 10 - Glaucoma. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.