Measured visual acuity (Logmar score)

Figure 5-5.  Mean (±1 standard error) of 13 gradings of macular thickening for eyes with cystoid macular edema (11 because of uveitis, two because of diabetes). Simple linear regression showed significant relationship between mean thickening and actual visual acuity. (From Nussenblatt RB, Kaufman SC, Palestine AG, et al. Macular thickening and visual acuity. Ophthalmology 1987; 94: 1134–9.)

Ancillary ophthalmic tests

will provide new insight into the pathophysiology of a number of uveitic disorders.

Laser flare photometry

Although standardized schemes for assessing anterior chamber cells and flare have been described in the literature, grading differs tremendously between clinicians and even for the same grader over time. A laser device has been developed to assess flare in the anterior chamber of the eye and should standardize the grading of anterior chamber inflammation; objective grading of flare is extremely useful in determining response to therapy.49,50 Furthermore, it is difficult to detect the induced flare caused by small amounts of protein in the aqueous humor resulting from early breakdown of the blood–aqueous barrier. After cataract surgery, for example, it would be nice to predict which eyes were at risk of developing uveitis and cystoid macular edema. The laser flare photometer is more sensitive than the eye in detecting flare and may be useful in predicting which eyes are at risk for developing worsening inflammatory disease, and possibly identifying eyes that require more aggressive antiinflammatory therapy. In one study of 30 uveitis patients, outflow facility was significantly reduced in patients with elevated flare photometry results.51 An association between laser flare photometry values and complications of uveitis has also been reported.52 However, randomized clinical trials have not demonstrated that increasing therapy to decrease laser flare photometry values improves clinical outcomes compared to basing therapy on clinical assessment.53

A B

Figure 5-6.  Proposed scheme as to why fluorescein leakage may appear to be same but macular thickening may have decreased, resulting in improvement in visual acuity. A, During an acute episode of uveitis, cystic spaces are filled with fluid and the macula is thickened. B, With therapy there is a reduction in macular thickening but the amount of leakage will appear to be the same if the angiogram is reviewed in standard fashion.

(From Nussenblatt RB, Kaufman SC, Palestine AG, et al. Macular thickening and visual acuity. Ophthalmology 1987; 94: 1134–9.)

choroidal blood flow, including choroidal neovascular membranes.41–44

ICG angiography has now been used to study patients with a number of uveitic conditions. In patients with serpiginous choroiditis, ICG angiography has demonstrated blockage of choroidal fluorescence in active areas of lesions with return of the normal choroidal fluorescence as the inflammation subsided.45 In addition, the chorioretinal lesions associated with birdshot choroiditis are often difficult to observe clinically or to document with fluorescein angiography. However, Krupsky and colleagues46 showed that ICG angiography was superior to fluorescein angiography in demonstrating these lesions that appeared as hypofluorescent areas, suggesting loss of the choriocapillaris. Herbort and colleagues47,48 have used ICG angiography to assess disease activity in several forms of uveitis, including VKH and Behçet’s disease. Researchers are also using ICG angiography to compare active and quiescent chorioretinal lesions in patients with uveitis, and it is hoped that this technique

Optical coherence tomography

Optical coherence tomography (OCT) allows the noninvasive assessment of retinal thickness. This technique may be useful in assessing retinal edema in patients with uveitis and response to therapy. In a recent study, Antcliff and associates54 compared OCT and fluorescein angiography in 58 patients with uveitis and suspected cystoid macular edema (CME). One hundred and eight eyes had similar results by both OCT and fluorescein angiography; 67 eyes had CME and 41 eyes had no CME. In 10 eyes subretinal fluid was detected by OCT but not by fluorescein angiography. Five of these eyes had CME detected by fluorescein angiography but not by OCT. Three other eyes had CME detected by fluorescein angiography but not by OCT. The authors concluded that OCT is as effective as fluorescein angiography for detecting CME but is superior for demonstrating axial distribution of fluid. Similar to fluorescein angiography, the accuracy of the measurements is affected by small pupil size and media opacity.

Since the last edition of this book there have been improvements in OCT technology and a number of new studies assessing the use in uveitis. OCT is useful for detecting macular edema and assessing response to therapy.55 Reductions in macular thickness in patients with uveitic CME can be detected on OCT within a week of corticosteroid therapy (Fig. 5-7). OCT may be useful in detecting retinal pathology in other forms of posterior uveitis.56 Finally, spectral-domain OCT may provide additional information and be useful in assessing uveitic eyes, especially when hazy media obscures clinical examination.57

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