Degree, duration and cause of vision loss in cases of uveitis

INTRODUCTION

Uveitis, an inflammatory disorder affecting the uveal tract of the eye, is a significant cause of visual morbidity worldwide, particularly among the working-age population. It encompasses a wide spectrum of ocular inflammatory conditions that may involve the iris, ciliary body, choroid, retina, vitreous and even adjacent ocular structures.^[1] The clinical presentation of uveitis varies by anatomical location, aetiology and duration of disease. If not appropriately diagnosed and managed, uveitis can result in permanent vision loss, making early identification and intervention critical.^[2]

The global burden of uveitis is substantial, accounting for approximately 10–15% of blindness in developed countries and even higher in developing nations.^[3] In India, the prevalence and patterns of uveitis are influenced by endemic infectious diseases, systemic autoimmune disorders and environmental factors.^[4] Posterior uveitis and panuveitis are particularly associated with more severe visual outcomes due to involvement of deeper ocular structures.^[5]

A wide range of infectious and non-infectious aetiologies have been linked to uveitis, including tuberculosis, toxoplasmosis, viral retinitis, human leucocyte antigen (HLA)-B27-associated spondyloarthropathy, sarcoidosis and Behçet’s disease.^[6] Tuberculosis-associated uveitis remains one of the most common causes of posterior and pan-uveitis in the Indian subcontinent.^[7] Moreover, idiopathic uveitis still represents a considerable proportion of cases, highlighting the challenge of accurate diagnosis despite advancements in imaging and serological testing.^[8]

The degree and duration of vision loss in uveitis patients depend on several factors, including promptness of treatment, anatomical type, aetiology and presence of complications such as cataract, glaucoma, cystoid macular oedema and retinal detachment.^[9] Chronic and recurrent inflammation may lead to irreversible structural damage, necessitating long-term immunosuppressive or anti-infective therapy.

Understanding the clinical patterns and causative factors of vision loss in uveitis is essential for guiding targeted diagnostic protocols and therapeutic strategies. Recent studies stress the importance of region-specific data for optimising uveitis management and reducing preventable blindness in resource-constrained settings.^[10] The aim of this prospective, observational, non-interventional study is to investigate the degree, duration and causes of visual loss in uveitis patients.

MATERIALS AND METHODS

A descriptive study was conducted on consecutive patients diagnosed with uveitis, who were referred to the M and J Western Regional Institute of Ophthalmology, a tertiary eye institute in western India. The study commenced in September 2018, enrolling a total of 50 patients who were followed for 2 years until August 2020. Ethical approval was taken from the Institutional Ethical Committee (Date: 07 September 2020 and letter no: 105/2020), and written informed consent was taken from all the participants.

Inclusion criteria involved patients’ aged 5 years and older, patients of either sex diagnosed with any form of uveitis [Figure 1].

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Figure 1:

Acute uveitis.

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Individuals in a severe or life-threatening condition, likely to be hospitalised in intensive care or requiring immediate and extensive medical intervention, and individuals who have other major eye conditions besides uveitis that could affect vision independently were excluded.

Each participant underwent detailed history taking and clinical evaluation. A structured questionnaire was used to document demographic and clinical details, including age, sex, religion, occupation, address and laterality. Detailed presenting complaints were noted, including onset and severity. Targeted history-taking explored possible aetiological associations such as tuberculosis (including family history), HLA-B27-related arthropathies, leptospirosis, toxoplasmosis, toxocariasis, leprosy, cytomegalovirus and systemic infections involving the respiratory, gastrointestinal, genitourinary, central nervous systems and dermatological conditions. The past ocular history, including prior inflammation, trauma, episodes of visual loss and treatment history, was also recorded.

Ocular examination involved assessment of best-corrected visual acuity, intraocular pressure and a detailed slit-lamp evaluation. Anterior segment findings noted included abnormalities in the lids (e.g. vitiligo, herpetic lesions), conjunctiva and sclera (e.g. sarcoid nodules, scleritis), corneal changes (e.g. keratopathy, ulceration, keratic precipitates), anterior chamber inflammation (flare, cells), iris abnormalities (e.g. nodules, synechiae, atrophy), pupil morphology and reactivity and lens changes (e.g. pigment deposits, cataractous changes). Intraocular pressure was measured using the Goldmann applanation tonometer [Figure 2].

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Figure 2:

Posterior synechia.

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Posterior segment examination was conducted using direct and indirect ophthalmoscopy as well as a three-mirror contact lens. Parameters assessed included vitreous opacities or haemorrhages, signs of vasculitis, retinitis, choroiditis, macular oedema, retinal detachment and optic nerve head changes such as papillitis, disc oedema and optic atrophy. Patients were considered to have permanent ocular damage if irreversible sequelae were present, such as macular scarring or atrophy, lamellar macular hole, or optic atrophy [Figure 3].

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Figure 3:

Macular scar.

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Each patient also underwent a systemic examination by a physician to screen for any associated systemic disease. Based on clinical suspicion, tailored laboratory investigations were ordered, which included total and differential leucocyte counts, erythrocyte sedimentation rate, Mantoux test, venereal disease research laboratory, enzyme-linked immunosorbent assay for human immunodeficiency virus I and II, rheumatoid factor and specific serologies such as immunoglobulin M assay for leptospirosis. Radiological and imaging evaluations included chest X-ray, sacroiliac joint imaging, fundus fluorescein angiography and B-scan ultrasonography [Figures 4 and 5].

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Figure 4:

Ultrasound biomicroscopy image of acute uveitis. (A) A slit lamp photograph of the anterior segment of the eye, showing the cornea, iris and lens. This image is used for clinical examination and initial assessment. (B) (Top Right) The yellow arrows point to areas of zonular stretching. Zonules are fine fibers that hold the lens in place. Stretching indicates trauma or weakness, which is a common finding in eyes with ocular trauma or lens instability. (C) (Bottom Left) The red arrow points to a ruptured anterior capsule of the lens. This suggests a tear or defect in the front surface of the natural lens within the eye, which can lead to inflammation or other complications. (D) (Bottom Right) Ultrasound biomicroscopy highlights subretinal fluid with a yellow star, which is indicative of fluid accumulation beneath the retina’s sensory layer.

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Figure 5:

Optical coherence tomography image of acute uvelitis.

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The final aetiological diagnosis was made by correlating clinical findings with investigation results and systemic evaluation. HLA-B27-related uveitis was diagnosed based on characteristic clinical features, including recurrent hypopyon uveitis, low backache, joint involvement and positive systemic evaluation. Endogenous endophthalmitis was identified by acute presentation with hypopyon, vitreous exudates on ultrasound and positive culture reports.

Visual loss was defined as best-corrected vision worse than 6/18. According to the World Health Organization definitions, the severity of vision loss is graded as follows:

1. Normal vision: Visual acuity better than or equal to 6/12 (or 20/40) in the better eye with best correction

2. Moderate vision impairment: Visual acuity worse than 6/12 but better than or equal to 6/60 (or 20/70–20/400). Individuals can generally function with corrective measures, but may have difficulty with tasks requiring detailed vision.

3. Severe vision impairment: Visual acuity worse than 6/60 but better than or equal to 3/60 (or 20/400–20/1200). Vision loss significantly impacts daily activities

4. Blindness: Visual acuity worse than 3/60 (or 20/1200), or visual field constriction to <10° around fixation. This classification indicates profound visual impairment.

Follow-up evaluations were conducted at regular intervals over the 2 years, with best-corrected visual acuity, intraocular pressure and slit-lamp examination performed at each visit. The final visual acuity was used to determine the extent of visual loss, rather than transient reductions noted during acute episodes. The duration of visual impairment was assessed cumulatively by calculating the total time across all uveitis episodes with impaired vision.

RESULTS

The age distribution in this study indicates that the majority of the cases are in the 21–30 and 41–50 years of age groups, followed by the 31–40 years of age group, with minimal observed in the younger age groups.

The gender distribution is relatively balanced, with 54% males and 46% females. There was no significant association between age and gender (P > 0.05). There was a single pediatric case included in the study. (1 case mentioned in the 0–10 years of age group) [Tables 1 and 2].

Table 3 presents the distribution of cases based on the course of uveitis. Out of the 50 patients evaluated, the majority (56%) had acute uveitis, while the remaining 44% exhibited chronic forms.

Table 4 illustrates the laterality of uveitis among the patients. Unilateral involvement was seen in 54% of cases, while 46% had bilateral uveitis.

Table 5 describes the anatomical classification of uveitis. The most frequent form was anterior uveitis, accounting for 44% of cases, followed by panuveitis at 36%, posterior uveitis at 16% and sclerouveitis at 4%.

Table 6 summarises the presence of associated systemic illnesses in patients with uveitis. Systemic disease was present in 36% of patients, while 64% had no identifiable systemic association.

Table 7 outlines the findings from investigative laboratory workups. Positive results were seen in small percentages of patients for rheumatoid factor (6%), C-reactive protein (4%), antistreptolysin O (4%), antinuclear antibody (2%) and sputum acid-fast bacilli (2%), while a significant majority (82%) showed no abnormal findings. These results suggest that although serological and immunological tests can aid diagnosis, many cases of uveitis may remain idiopathic or require clinical correlation for a definitive diagnosis.

Table 8 describes the degree of vision loss. Nearly half of the cases have severe vision loss, with a smaller proportion experiencing mild or moderate impairment.

Table 9 summarises the duration of vision loss among the studied individuals. The majority of individuals have experienced vision loss for a period ranging from a few months to 2 years.

Table 10 outlines the causes of visual loss among 50 cases, including the number and percentage of cases attributed to each cause. This data demonstrates that anterior chamber inflammation is the most common cause, either alone or combined with other conditions, accounting for a significant portion of vision loss cases.

DISCUSSION

This prospective study provides insight into the clinical patterns of uveitis and its association with vision loss in a tertiary care hospital setting in India.

In the current study, acute uveitis was more common than chronic (56% vs. 44%), a finding consistent with recent observations in developing countries, where infectious causes dominate the aetiological spectrum.^[11] Acute presentations, if treated promptly, tend to have a more favourable prognosis, while chronic and recurrent cases often lead to cumulative damage and long-term visual impairment.

Unilateral presentation was observed in the majority of patients (54%), which aligns with findings by GonzálezLópez et al., who reported that unilateral uveitis is more often associated with idiopathic or infectious aetiologies, whereas bilateral disease is suggestive of systemic inflammatory conditions.^[12] In the present study, although unilateral cases were slightly more prevalent, the high proportion of bilateral involvement (46%) underscores the need for systemic work-up in a large number of patients.

When classified by anatomical involvement, anterior uveitis was the most common subtype (44%), followed by panuveitis (36%) and posterior uveitis (16%). These results are in line with a multicentric study from South Asia, which reported anterior uveitis as the most frequent form, but with a rising trend in panuveitis due to tuberculosis and autoimmune associations.^[13] Panuveitis, due to its extensive involvement of the entire uveal tract, is often associated with severe and irreversible visual impairment.

About 36% of patients had systemic illnesses, emphasising the importance of interdisciplinary collaboration. This emphasises the importance of a thorough systemic evaluation in uveitis cases, especially when the aetiology is not immediately apparent. Diseases such as tuberculosis, sarcoidosis and HLA-B27-related conditions are commonly implicated and must be ruled out or confirmed. Diseases such as tuberculosis, rheumatoid arthritis and viral infections are known to cause or exacerbate ocular inflammation. In their recent review, Agarwal et al. emphasised the value of systemic screening, particularly in countries such as India, where tuberculosis and parasitic infections remain endemic.^[14]

Despite a comprehensive clinical and investigative protocol, 64% of patients in our study had negative serological workups, suggesting a high rate of idiopathic uveitis, which is also reported in global literature. Yadav et al. suggested that although modern imaging and laboratory techniques have enhanced diagnostic accuracy, a significant number of cases still require clinical judgment for aetiological classification.^[15]

The most common causes of visual loss were anterior chamber inflammation, followed by cataract. CME, choroiditis, glaucoma, retinal detachment and optic disc pallor were the causes of severe visual loss, which was comparable to Rothova et al. and Durrani et al.^[16,17]

This study reinforces the need for a structured approach in uveitis management, combining detailed ocular examination with systemic evaluation and targeted laboratory testing to arrive at a comprehensive diagnosis and prevent long-term visual disability. A limitation of the study is sample size is too small for generalisation of the study findings. Another limitation was severity, cause and duration of vision loss, which has also not been studied for specific sub-types of uveitis, aetiology-wise or anatomical location-wise wise and since uveitis is a chronic and/or recurrent condition, the duration of the study is also a limitation.

CONCLUSION

The study demonstrates that uveitis remains a heterogeneous condition with varying clinical presentations. Acute and anterior uveitis were the most common forms observed, with unilateral involvement slightly more frequent. A significant proportion of patients exhibited systemic disease associations, although a majority had negative serologic findings, reinforcing the complexity and diagnostic challenge of uveitis. Recognising the anatomical type, systemic correlations and pattern of visual loss is crucial for early intervention and improved visual outcomes. These findings highlight the importance of an integrated ophthalmic and systemic evaluation in tertiary care settings, especially in regions with diverse aetiological backgrounds.