Fig. 4.23 Posterior scleritis with annular retinochoroidal and serous retinal detachment

Fig. 4.24 Same eye as shown in Fig. 4.23. Fluorescein angiogram, conÞrming the Þndings described in Fig. 4.23

head down; despite a cloudy subretinal ßuid, a pale gray subretinal mass with a surrounding dark gray line and an overlying normal choroidal vascular pattern may sometimes be visible through the poorly mobile bullous serous retinal detachment. The bullous serous retinal detachments do not have retinal holes or Þxed retinal folds. The ciliochoroidal or retinal detachments usually resolve completely with prompt and aggressive treatment of the scleritis. Although they may disappear within hours, they are often absorbed slowly over a period of several weeks or months, leaving only a diffuse pigmentation in the affected area; however, if the macular area has been

involved, loss of vision will remain as a permanent sequela [5].

Associated Diseases

Disease association in posterior scleritis is less common than in anterior scleritis [2, 7]. In our series of 31 patients with posterior scleritis, 6 (19%) were found to have an associated systemic disease (Table 4.4). This is in contrast to the 36% disease association found in our patients with anterior scleritis. Diagnoses included psoriatic arthritis in two patients, HLA-B27+ (without spondyloarthropathy)-associated scleritis in one patient, arthritis and inßammatory bowel disease in one patient, systemic lupus erythematosus in one patient, and tubulointerstitial nephritis and uveitis syndrome in one patient (Table 4.5).

Complications

Posterior uveitis is universally present in posterior scleral inßammation because the choroid is always involved by the adjacent posterior scleral inßammation; [2, 6] anterior uveitis may also appear, but it is often associated with concomitant anterior scleritis. Glaucoma, particularly in combination with uveitis, is considered to be an ominous sign in the course of scleritis because its presence indicates a more diffuse and severe process [3]. Whether caused by anterior uveitis, ciliochoroidal detachment, angle neovascularization, or chronic use of steroids, increased intraocular pressure in posterior scleritis may result in the development of irreversible optic nerve damage [9, 100].

Ancillary Tests

Ultrasonography

Ultrasonography is the most useful test in the diagnosis of posterior scleritis because it shows the ßattening and thickening of the posterior coats of the eye (choroid and sclera) associated with retrobulbar edema [84, 86, 89, 101] (Fig. 4.25). Occasionally, retinal and choroidal detachments may also be detected. B-scan ultrasonography shows multiple internal echoes in the area of the scleral thickening and lack of echoes in the area of retrobulbar edema; the multiple echoes remain after sound beam attenuation, indicating high

Fig. 4.25 B scan ultrasonogram with superimposed A scan proÞle. Note the thickening of the retinal choroid layer and the edema in TenonÕs space

Fig. 4.26 Ultrasonogram of a patient with posterior scleritis. Note particularly the A scan tracing showing the multiple retrobulbar echoes. The multiple echoes in the area of the sclera indicate high internal reßectivity of the sclera

Fig. 4.27 Ultrasonogram of choroidal thickening in a patient with chronic uveitis without scleritis. Note particularly the A scan tracing showing a lack of high internal reßectivity in the area of the sclera with sound beam attenuation

Fig. 4.28 Ultrasonogram ÒTÓ sign formed by the sonagraphically, empty space occupied by the optic nerve and the edematous TenonÕs space adjacent to the optic nerve

internal reßectivity of the scleral mass (Fig. 4.26). On the other hand, in choroidal thickening without scleral thickening, the echoes do not remain after sound beam attenuation (low internal reßectivity) (Fig. 4.27). When retrobulbar edema surrounds the optic nerve, the ÒTÓ sign may appear, which consists of a lack of echoes in the edematous TenonÕs space and adjacent optic nerve (Fig. 4.28). A-scan ultrasonography shows highamplitude internal spikes in the area of the scleral thickening and low-amplitude internal spikes in the area of retrobulbar edema. The combination of both A scan and B scan techniques gives the most useful results in distinguishing posterior scleritis

from orbital, choroidal, and retinal entities that clinically may mimic it (Tables 4.7Ð4.9) [86].

Computerized Tomography (CT) Scanning

Computerized tomography also shows scleral thickening, the image of which can be enhanced by radiopaque medium injection [86, 102]. Retrobulbar edema may also be seen. The ability of computerized tomography to delineate extraocular muscles, lacrimal glands, optic nerves, scleral coats, orbital walls, and paranasal tissues helps to detect extraocular muscle or lacrimal gland enlargement, optic nerve or scleral inßammation, bone erosion, and sinus involvement,

Table 4.7 Differential diagnosis of posterior scleritis: proptosis, chemosis, lid swelling, and limitation of ocular movements

118

Scleritis and Episcleritis of Considerations Clinical 4

Table 4.8 Differential diagnosis of posterior scleritis: subretinal mass

Scleritis 2.4

119

Table 4.9 Differential diagnosis of posterior scleritis: serous detachment of choroid, ciliary body, and retina

120

Scleritis and Episcleritis of Considerations Clinical 4