Ординатура / Офтальмология / Учебные материалы / Uveitis Text and Imaging Text and Imaging Text and Imaging 2009

such as PCR. Local aqueous humor antibody production against herpes virus can be done by indirect immunofluorescence calculating the GoldmannWittmer coefficient. Local antibody production is considered to be positive when the GoldmannWittmer coefficient exceeds 3.

Oral acyclovir at a dosage of 400 mg 5 times per day for several weeks is usually used to treat herpetic anterior uveitis. Intravenous acyclovir (10 mg/Kg per day) may be proposed in severe forms of anterior uveitis and must be proposed to all immunocompromised hosts.35 Alternatively, one may use valacyclovir, 1 g three times daily, or famciclovir, 500 mg three times daily.

Most patients with active herpetic anterior uveitis also require a topical corticosteroid and a cycloplegicmydriatic agent, both to prevent posterior synechiae formation and for improved comfort. Anti-inflam- matory therapy should be started with moderately high dose (5 × daily) topical prednisolone acetate, dexamethasone, or betamethasone for a period of 8-10 days followed by gradual, slow tapering over weeks to months.35 Herpetic uveitis or kerato-uveitis is rapidely responding to corticosteroids and systemic steroids are never required. Very often patients require a very low dose of topical corticosteroid indefinitely to maintain long-term control of their inflammation. Long-term antiviral prophylaxis may be important to prevent additional episodes, which is required, at least topically, when prolonged topical corticosteroid therapy is necessary.

VARICELLA-ZOSTER VIRUS (VZV)

Anterior uveitis is much more common after herpes zoster ophthalmicus, especially without acyclovir prophylaxis, and is often delayed relative to the onset of cutaneous lesions (Figure 9). The diagnosis of VZV uveitis may be particularly difficult in cases without a previous zoster dermatitis.36 Anterior uveitis is often acute, unilateral, granulomatous, and associated with posterior synechiae and increased intraocular pressure. Additional typical findings include iris sector atrophy and sphincter damage which cannot be distinguished from herpes simplex iris atrophy. Hypopion and hyphema may also occur. Anterior uveitis is less frequent after an episode of varicella.37

Figures 9A and B: Herpes Zoster ophthalmicus in a 60-year old woman. (A) Cutaneous eruption in the territory of the ophthalmic division of the trigeminal nerve. (B) Anterior granulomatous uveitis with large pigmented keratic precipitates and iris patchy atrophy

The diagnosis of VZV anterior uveitis is primarily based on the analysis of clinical features that are indistinguishable from herpes simplex anterior uveitis when it is not accompanying herpes zoster dermatitis. Laboratory tests can be useful.

In immunocompetent patients, early treatment of herpes zoster ophthalmicus by oral acyclovir (5 × 800 mg/day) may reduce the incidence of keratouveitis and uveitis from 50 percent to 29 (or 27%).36 Curative treatment of anterior uveitis includes associations of systemic antiviral agents (Acyclovir, valacyclovir), corticosteroids, and antiglaucomatous medications.

CYTOMEGALOVIRUS (CMV) ANTERIOR UVEITIS

CMV anterior uveitis in immunocompetent, frequently eldery patients is a newly described entity. It is

characterized by the following features: chronic, mild to moderate inflammation, small size white or brown keratic precipitates, secondary glaucoma, and absence of posterior segment involvement.35

CMV-associated anterior uveitis is resistant to acyclovir. Infection can be controlled with intravenous ganciclovir or foscarnet or oral valgancyclovir.

EPSTEIN-BARR VIRUS (EBV) UVEITIS

Benign and transitory uveitis has been described in patients with EBV-associated infectious mononucleosis. Uveitis may be chronic, uni or bilateral, granulomatous, and associated with diffuse iris atrophy and severe glaucoma.35

Treatment of EBV-associated uveitis is highly controversial because most antiviral agents have no effect on EBV and ocular disease is usually self-limited.

HUMAN T-CELL LYMPHOTROPIC VIRUS, TYPE 1 (HTLV-1)

Typical findings include vitritis and retinal vasculitis with mild anterior segment inflammation. Some patients with HTLV-1 show anterior granulomatous uveitis without posterior segment inflammation.38

FUNGAL GRANULOMAS

The surface of the eye is armed with mechanical barriers and immunologic mechanisms. However once anatomical barriers are breached and exposed to microorganisms, the host defenses are often insufficient to protect. The exposure of the eye directly to the environment renders it vulnerable to infectious diseases caused by fungi specifically after accidental (Figure 10) or surgical trauma (Figure 11).39 The majority of the clinically important species of fungi belong to filamentous fungal infections and are common after a penetrating trauma by objects contaminated by vegetable matter. Occasionally the mode of infection is by extension from adjacent paranasal sinuses do occur. Surgical aspiration is required for isolation of the microorganism and to strat a specific treatment. Topical, oral or intravitreal anti fungal treatment is advised depending upon the severity of infection.

Figures 10A and B: A small iridolenticular granuloma can be seen over the cataractous lens with posterior synechiae in a 60-year-old male with a history of penetrating injury. Injury was by a thorn, a vegetable matter. The patient had no systemic complaints. (B) Aspiration and culture resulted in isolation of Cladosporium spp.on lactophenol cotton blue staining

PRESUMED TREMATODE INDUCED

ANTERIOR CHAMBER GRANULOMA

Uveitis is an important cause of ocular morbidity in children, and the diagnosis and management can be particularly challenging.40 The causes vary widely depending upon geographic, cultural, environmental, and socioeconomic factors. Juvenile idiopathic arthritis and toxoplasmic retinochoroiditis are the leading causes of paediatric anterior and posterior uveitis in most of the countries. Other causes include sarcoidosis and Behcet’s disease, intermediate uveitis and Fuchs’ heterochromic iridocyclitis. Compared with non-

Figures 11A and B: (A) A 51-year-old male underwent uncomplicated right cataract surgery. Postoperatively, he developed a low-grade chronic anterior uveitis with cystoid macular oedema in the operated eye. This was controlled on topical steroids with a VA of 6/9 until he presented with a flare up 7 months later. VA had dropped to 6/60 in the RE. (A) Corneal oedema, anterior chamber inflammatory reaction and dense white infiltrative lesion at the corneal endothelium were seen at 3 o’ clock position. (B) Anterior chamber tap was performed which revealed Scedosporium spp on lactophenol cotton blue staining

granulomatous process, granulomatous uveitis is rare in children. Masquerade syndromes mimic granulomatous uveitis in children include juvenile xanthogranuloma, leukemic infiltrates in the iris, and retinoblastoma seeding of the iris. Recently anterior granulomatous uveitis presumably due to trematode infestation was reported from south India in pediatric patients who were exposed to village pond or river water.41,42 The occurrence of parasitic anterior uveitis in children appears to be a unique feature in this geographic location. These patients also provided a history of itching all over the body with or without

swelling of the mucosal areas after swimming in the local river or pond prior to developing the granulomatous uveitis. The clinical picture is characterized by well circumscribed anterior chamber nodules with or without mutton-fat keratic precipitates, cells and flare in the anterior chamber. These nodules measured 2 to 5 mm in diameter and were mostly located at the 6-o’clock position of the anterior chamber, posterior to the cornea (Figures 12A-D) or on the iris surface. In addition to anterior chamber granuloma, several children also had subconjunctival nodules in the affected eyes (Figure 12E). Histologic analysis of these scleral nodules revealed a tegument and/or the internal structures of a trematode surrounded by a zonal granulomatous inflammation, one such nodule showed the presence of oral and ventral suckers, characteristic of Trematodes.42 Although none of the anterior chamber nodule aspirates showed the Trematode structures, similar age distribution, exposure to the same water source, and similar inflammatory responses on histopathological study both in subconjuctival granuloma and anterior chamber granuloma suggest possibility of same aetiology for both the conditions. The extraocular manifestations were self-limiting and disappeared without treatment. It is reported that the smaller granulomas need only topical steroids. However to maximize the visual potential and minimize complications it is important to surgically remove the granulomas specifically when they are bigger than 3 mm.42

LENS PROTEIN UVEITIS

Lens induced uveitis is the most important and common cause of anterior uveitis in geriatric age group. In cases of phacolysis, a hypermature cataract leaks out the liquefied cortical material into the anterior chamber. Macrophages engulf the lens material. Flare, cells and non granulomatous KPs are seen on slit lamp examination. Phacotoxic uveitis occurs when the released lens proteins are recognized as antigens. It presents as acute granulomatous anterior uveitis usually with glaucoma, slitlamp examination could reveal corneal oedema, granulomatous KPs and a hypermature cataract (Figure 13). Control of glaucoma and surgical removal of cataract are needed to control uveitis.43-45

Figures 14A and B: A previously healthy 26-year-old man was referred for mild blurring of vision in his right-eye, persisting for 2 days. Patient gave a significant history of fall of an insect in his right eye prior to the eye problem. (A) Slit-lamp examination showed clear conjunctiva, a single large granulomatous keratic precipitate and an insect hair in the middle of the KP. Moderate anterior chamber and anterior vitreous inflammation was also seen in his right eye. Dilated fundus examination was unremarkable in both eyes. (B) The granuloma disappeared with application of topical steroids

VOGT-KOYANAGI-HARADA DISEASE AND SYMPATHETIC OPHTHALMIA (SEE CHAPTERS ELSEWHERE)

Vogt-Koyangi-Harada (VKH) disease and sympathetic ophthalmia are diseases of the posterior uvea that typically produce associated anterior granulomatous uveitis. In VKH, when posterior disease is burnt out with sunset-glow fundus the uveitis becomes exclusively anterior. These entities are described in detail in their respective chapters.

KEY POINTS

•Classification into granulomatous vs non granulomatous entity is purely based on slit lamp examination, not on any pathologic criteria.

•Causes of granulomatous uveitis vary from infectious, non infectious to masquerade syndrome.

•Sarcoidosis is the most common non infectious cause of anterior granulomatous uveitis

•Most common infectious causes include tuberculosis, syphilis, viral disease, and leprosy in specific endemic areas.

•Occasionally a rare aetiology may be noted such as a foreign body reaction after trauma (Figures 14A and B).

•Comprehensive, medical, and ophthalmologic histories followed by a complete ocular examination including slitlamp biomicroscopy, tonometry, and indirect ophthalmoscopy will help in the clinical diagnostic hypothesis which will be ruled in or ruled out with definitive laboratory investigations.

REFERENCES

1.Smith RE, Nozik RA. Uveitis: A clinical approach to diagnosis and management, Baltimore, Williams and Wilkins, Ed 2, 1989;23-6.

2.Rao NA, Forster DJ, Aigsburger JJ. General approach to the uveitis patient. The Uvea. Uveitis and Intraocular neoplasms. New York, London, Gower Medical publishing, 1992;2:1-8.

3.Duke-Elder S, Dobree JH. System of Ophthalmology: Diseases of the retina, St.Louis, Mosby, 1967;10.

4.Nussenblatt RB, Whitcup SW, Palestine AG. Anterior uveitis. Uveitis: Fundamentals and Clinical Practice: St. Louis, CV Mosby, 1996;265.

5.Nussemblatt RB, Whitcup SM, Palestine AG. Sarcoidosis. In: Nussemblatt RB, Whitcup SM, Palestine AG, (Eds): Uveitis. Fundamentals and clinical practice. St Louis: Mosby-Year Book, 1996;289-98.

6.Tanoue LT, Elias JA. Systemic sarcoidosis. In: Textbook of Pulmonary Disease. 6th ed. Lippincot-Raven; 1998;40728.

7.Rothova A. Ocular involvement in sarcoidosis. Br J Ophthalmol 2000;84:110-16.

8.Friedberg DN, Latkany ML. Ocular Complications of tuberculosis. In: Rom WN, Garay S (Eds): Tuberculosis. Boston, Little, Brown and company, 1995;557-66.

9.Dunn JP, Helm CJ, Davidson PT. Tuberculosis. In: Pepose JS, Holland GN, Willhelmus KR (Eds): Ocular Infection and Immunity, St.Louis, Mosby, 1996;1421-9.

10.Donahue HC. Ophthalmic experience in a tuberculosis sanatorium. Am J Ophthalmol 1967; 64: 742-8.

11.Tabbara KF. Ocular tuberculosis: anterior segment. Int Ophthalmol Clin 2005;45:57-69.

12.Samson MC, Foster CS. Tuberculosis. In: Foster CS, Vitale AT (Eds): Diagnosis and Treatment of Uveitis. WB Saunders Company: Philadelphia, 2002;264-72.

13.Thompson MJ, Albert DM. Ocular tuberculosis. Arch Ophthalmol 2005;123:844-9.

14.Alvarez S, McCabe WR. Extrapulmonary tuberculosis revisited: a review of experience at Boston City and other hospitals medicine 1984;63:25-55.

15.Rathinam SR, Cunningham ET. Infectious causes of uveitis in the developing world. Int Ophthalmol Clin 2000;40:13752.

16.Gowri Priya C, Rathinam SR, Dharmalingam K, Namperumalsamy P. Anterior chamber granuloma in adult male—A case report. J TNOA 1999;2:49-52.

17.Woods AC. Endogenous uveitis. Baltimore: Williams and Wilkins 1960;137-49.

18.Hogeweg M, Faber WR. Progression of eye lesions in leprosy: ten-year follow-up study in the Netherlands. Int J Leprosy 1991;59:392-7.

19.Lewallen S, Tungpakorn NC, Kim SH, et al. Progression of eye disease in “cured” leprosy patients: implications for understanding the pathophysiology of ocular disease and for addressing eyecare needs. Br J Ophthalmol 2000;84:81721.

20.Thompson K, Job CK. Silent iritis in treated bacillary negative leprosy Int J Lepr Other Mycobact Dis 1996;64: 306-10.

21.Desikan P, Desikan KV. Persistence of lepromatous granuloma in clinically cured cases of leprosy. Int J Lepr Other Mycobact Dis 1995;63:417-21.

22.Ebenezer Daniel, Gigi J Ebenezer, Charles K. Job Pathology of iris in leprosy. Br J Ophthalmol 1997;81:490-2.

23.Canizares O, Costello M, Gigli I Erythema Nodosum type of lepra reaction. Arch Ophthalmol. 1962;85:29-40.

24.Hussein N, Ostler HB. Hansen Disease. In: Pepose JS, Holland GN, Wilhelmus KR, (Eds): Ocular Infection and Immunity. St.Louis, Mosby, 1996;1421-9.

25.Spaide R, Nattis R, Lipka A, Amico RD. Ocular findings in leprosy in the United States. Am J Ophthalmol 1985;100:411-6.

26.Ffytche TJ. Role of iris changes as a cause of blindness in lepromatous leprosy. Br J Ophthalmol 1981;65:231-9.

27.Malla OK, Brandt F, Anten JG. Ocular findings in leprosy patients in an institution in Nepal (Khokana). Br J Ophthalmol 1981;65:226-30.

28.Espiritu CG, Gelber R, Ostler HB. Chronic anterior uveitis in leprosy: an insidious cause of blindness Br J Ophthalmol 1991;75:273-5.

29.Citirik M, Batman C, Aslan O, Adabag A, Ozalp S, Zilelioglu O. Lepromatous iridocyclitis.Ocul Immunol Inflamm 2005;13:95-9.

30.Nepal BP, Shrestha UD. Ocular findings in leprosy patients in Nepal in the era of multidrug therapy. Am J Ophthalmol 2004;137:888-92.

31.Daniel E, Koshy S, Joseph GA, Rao PS. Ocular complications in incident relapsed borderline lepromatous and lepromatous leprosy patients in south India. Indian J Ophthalmol 2003;51:155-9.

32.Aldave AJ, King JA, Cunningham ET Jr. Ocular syphilis. Curr Opin Ophthalmol 2001;12:433-41.

33.Samson MC, Foster CS. Syphilis. In: Foster CS, Vitale AT (Eds): Diagnosis and Treatment of Uveitis. WB Saunders Company: Philadelphia, 2002;237-44.

34.Tamesis RR, Foster CS. Ocular syphilis. Ophthalmology. 1990;97:1281-7.

35.Bodaghi B, Le Hoang P. Herpes Viruses in Ocular Inflammation. In: Edt U Pleyer, Mondino B (Eds): Uveitis and Immunological Disorders. Springer 2005;141-59.

36.Liesegang TJ. Herpes zoster virus infection. Curr Opin Ophthalmol 2004;15:531-6.

37.Naseri A, Good WV, Cunningham ET Jr. Herpes zoster visclerokeratitis and anterior uveitis in a child following varicella vaccination. Am J Ophthalmol 2003;135:415-7.

38.Goto K, Saeki K, Kurita M, Ohno S. HTLV-1-associated uveitis in central Japan. Br J Ophthalmol 1995;79:1018-20.

39.McDonnell PJ, McDonnell JM, Brown RH, et al. Ocular involvement in patients with fungal infections. Ophthalmol 1985;92:706-9.

40.Cunningham ET Jr. Uveitis in children. Ocul Immu Inflam 2000;8:251-61.

41.Rathinam SR, Usha KR, NA Rao. Presumed Trematode induced granulomas of anterior chamber: A newly recognized cause of uveitis in children from South India. Am J Ophthalmol 2002;133:773-9.

42.Rathinam SR, Fritsche T. Srinivasan M, et al. An outbreak of Trematode-induced granulomas of the conjunctiva Ophthalmology 2001;108:1223-9.

43.Cousins SW, Mackiw EK. Lens associated uveitis. In: Pepose JS, Holland GN, Wilhelmus KR, (Eds): Ocular Infection and Immunity. St.Louis, Mosby, 1996;507-28.

44.Thach AB, Marak GE Jr, McLean IW, Green WR. Phacoanaphylactic endophthalmitis: a clinicopathologic review. Int Ophthalmol 1991;15:271-9.

45.Rao NA. Lens induced uveitis. In: Tasman W, Jaeger EA, (Eds): Disease of the uvea. Duane’s clinical ophthalmology, Lippincott, 1992; Chapter 49.

Intermediate uveitis is a term (clinical picture) with which clinicians are most uncomfortable because it has erroneously been used to describe a clinical entity whereas it is simply and should fully be used as an anatomical notion, like anterior uveitis, that includes several clinical entities. This uncomprehensiveness is well expressed in an editorial written by Aaberg in the American Journal of Ophthalmology in 19871 and remains enigmatous till date.2

CLINICAL ANATOMY

Uveal tract, the vascular middle layer of the eye comprises the iris anteriorly, the ciliary body in the middle and the choroid posteriorly. The ciliary body extends from the iris root in the anterior to the ora serrata in the posterior. The anterior portion is the pars plicata (corona ciliaris) and consists of 70 to 80 ciliary processes. The posterior portion is the pars plana, a flat extension from the posterior aspect of ciliary processes to the ora serrata. This is about 3.5 to 4 mm in length (Figure 1).

NOMENCLATURE

There has been a lot of confusion and different terminologies used for inflammatory diseases of the anterior part of the posterior segment including the vitreous. In 1908 the disease has been described as ‘Cyclitis’ by Fuchs.3 A detailed description was given by Charles Schepens from Boston, USA, who was the pioneer of modern indirect ophthalmoscopy and examination of the peripheral retina by scleral depression. He termed the disease ‘peripheral uveitis’.4 The term ‘pars

Figure 1: Cut section of the globe showing site of inflammation in pars planitis ( please indicate structures with arrows)

planitis’ was coined by Welch, Maumenee and Wahlen in 1960.5 The disease was subsequently named chronic cyclitis, vitritis, peripheral uveitis, cyclochorioretinitis, chronic posterior cyclitis, etc. by several authors.6 Bec and associates7 called it ‘basal or peripheral uveoretinitis’ describing a group of patients where inflammation is restricted over the vitreous base.

In this work, we are going to use the term intermediate uveitis in its anatomical sense as it should be used. The first step which should be done when a patient presents with a uveitis of the anterior part of the posterior segment is to verify whether it is occurring within the anatomical location compatible with intermediate uveitis (vitritis and inflammation of the retina beyond the equator and the pars plana). The presence of a cystoid macular oedema is a complication of intermediate uveitis and does not preclude this

entity. Then, one needs to search for specific entities such as sarcoidosis (which can present as intermediate uveitis), intermediate uveitis related to multiple sclerosis and others (see Table 1 of entities that can present as intermediate uveitis). When all the workup has been done and the clinical features are typical for pars planitis (bilateral involvement, no synechiae, snow balls, snow banks, vitritis), then the term intermediate uveitis of the pars planitis type is used. When typical features for pars planitis are not present then the term should be intermediate uveitis of the idiopathic type.

In 1987, the International Uveitis Study Group (IUSG) recommended the usage of the term ‘Intermediate Uveitis’ to denote an idiopathic inflammatory syndrome, mainly involving the anterior vitreous, peripheral retina, and ciliary body, with minimal or no anterior segment or chorioretinal inflammatory signs.8

The term intermediate uveitis was unfortunately qualified to be equivalent to pars planitis by the IUSG Publication and shed a lot of confusion as pars planitis should be considered a subset of intermediate uveitis as explained here above.

EPIDEMIOLOGY

The disease has been found in 8 to 22% of uveitis patients9-11 and remains one of the commonly encountered uveitic entities all over the world. In Sankara Nethralaya, a major tertiary care referral eye institute in India it has been detected in 19.8% of all uveitis patients in a year in the uveitis clinic.11 The referral nature of posterior segment disease may influence the higher statistical figure in this study.

It is difficult to determine the age of presentation of this disease as it can remain mild or quiescent for

Table 1: Chronology of nomenclature of intermediate uveitis

Intermediate Uveitis International Uveitis Study Group 1987

several years. Hence the patients often do not report to the ophthalmologist at this stage.

The majority of the patients who present to the ophthalmologist are young. Most of the published series reported an average patient age of 23 to 28 years. Some studies reflected a bi-modal age distribution with peaks in the 2nd and 5th decades of life. The disease can occur in young children in whom the severity of the disease has been reported high. In our study of pars planitis cases, 7.5% of all pars planitis patients were found to be below 12 years of age.

Bilaterality is seen in 70 to 90% in both adults and children at presentation. Asymmetric presentation with one eye having minimal involvement is seen in about 25% cases. Unilateral cases can become bilateral subsequently at least in 10% of cases.12

Demography of intermediate uveitis is summarised in Table 2.

Table 2: Demography of intermediate uveitis

CLINICAL FEATURES

Intermediate uveitis may be underdiagnosed uveitic entity as early stages presenting with vitreous cells alone and without definite pars plana exudates can be missed, labelled and treated as anterior uveitis (Figure 2). The fact that routine pars plana examination is not done in patients presenting with symptoms of anterior uveitis is also cause for underdiagnosis. There is also a lack of awareness and misconception of this entity. The condition also tends to get misdiagnosed as posterior uveitis, vitreous haemorrhage, or endophthalmitis due to its varied presentations at different stages of the disease.

Pars planitis, a specific entity within the anatomical group of intermediate uveitis, is characterised by cells and debris in the vitreous, exudates in the pars plana and peripheral retina. The disease is sometimes associated

with mild periphlebitis in the vicinity of the exudates, and a non-granulomatous ‘spill over’ anterior uveitis that does not cause any synechiae. It is almost always bilateral. It may however be asymmetrical with the less affected eye showing only a few cells in the vitreous. Systemic work-up in these cases is negative and it is an exclusion diagnosis. Nevertheless it should be considered as a separate entity.

These patients usually have very few complaints initially. There may be mild blurring of vision, floaters and rarely, mild photophobia. In intermediate uveitis, unlike other uveitis conditions the eye is white and reasonably quiet, rarely becoming red and painful. There is usually no gross diminution of vision at the initial stages. The benign nature of the disease can result in postponement of the patient’s visit to the ophthalmologist. Patients typically complain of seeing floaters. Impairment of central vision in the initial stages is usually mild and mainly occurs due to cystoid macular oedema or early cataractous changes. Severe vision loss can occur in the late stages due to retinal detachment, complicated cataract, uveitic glaucoma or chronic cystoid macular oedema. In our earlier study (of 121 patients), 60% had a visual acuity of 6/9 or better.13

Slit lamp examination reveal a few cells in the anterior vitreous. Anterior uveitis can occur due to spill over of inflammation from the pars plana and is typically nongranulomatous. In the late stages, one may see very largely, synechiae and complicated cataract. In case of large KPs the diagnosis of sarcoidosis,14 tuberculosis and lyme disease15 must be searched.

Fundus examination typically reveals multiple snow ball opacities in the vitreous in the peripheral fundus (Figure 3). Exudates though commonly seen inferiorly can also be identified in any other quadrant, though less frequently. These inflammatory exudates accumulate over the pars plana to form a typical ‘snow bank’, which is a unique feature of the disease (Figure 4).

One may see periphlebitis of the peripheral veins in the vicinity of the exudates. Such changes rarely extend to the posterior pole. Arterioles can also be involved. Clinically detectable vascular involvement occurs in 10 to 32% of eyes.7,16 As the more explicit findings are localised at the periphery, examination by

Figure 4: Fundus photograph showing typical snow banking

Figure 5: Fundus photograph showing cystoid macular oedema in a case of chronic pars planitis

Figure 6: Fundus fluorescein angiogram in the late phase showing hyperfluorescence with typical petalloid appearance in a case of pars planitis with cystoid macular oedema

indirect ophthalmoscopy and scleral depression is a must for proper evaluation. Therefore observance of pars plana exudates is however not mandatory to the diagnosis of intermediate uveitis. In fact, Henderly et al12 have found that 24% of the patients of pars planitis can have vitreous cells in the other eye, it probably being the early sign of this disease. An increased incidence of cystoid macular oedema has been reported in eyes of pars planitis with ‘snow banks’. Poor visual acuity has been reported in patients of pars planitis with large snow banks.17 A careful evaluation of macula is particularly important in intermediate uveitis. Macular changes are commonly seen in these patients and occur in 28% of cases.17 In our study 25.2% of the patients with pars planitis had various types of macular pathology, of which cystoid macular oedema was the most common13 (Figure 5). Macular changes increase with the severity and duration of the disease. Fundus fluorescein angiography (FFA) typically shows petalloid hyperfluorescence (Figure 6). FFA can detect cystoid macular oedema (CMO) more commonly than clinically, emphasizing the role of ordering fundus fluorescein angiography at the earliest suspicion of CMO in these cases. OCT detects even more subtle changes in the macula and is fast becoming an essential tool in the diagnosis and management of intermediate uveitis. The other macular changes include macular hole (Figure 7) and epiretinal membrane formation over the macula (Figure 8). Optic disc oedema can also be seen in some cases.

Figure 7: Fundus photograph showing macular hole in a case of pars planitis

NATURAL COURSE, COMPLICATIONS AND PROGNOSIS

The natural course of intermediate uveitis of the pars planitis type is varied. Smith et al found that 10% of patients had a self-limited course with no recurrence, 59% had prolonged course with exacerbations, and 31% had a chronic smoldering course with few episodes of exacerbations.6 Such a varied natural course warrants a strategy of periodic evaluation of patients. Once the diagnosis is established the recurrent nature of this disease and the need for periodic evaluation