In Vivo Confocal Microscopy of Keratic Precipitates in Infectious Versus Noninfectious Uveitis

Evolution of research in diagnosis and management of uveitis over four decades in India

Uveitis and its complications are more common in the developing world, in which the condition occurs in up to 714 per 100,000 in the population and accounts for up to 25% of all blindness. In India, the ophthalmic sub speciality of uveitis greatly evolved in the last four decades. In the early decades most of the studies were epidemiological studies. In recent years, more research has been published due to tremendous advancements in clinical diagnosis, laboratory investigations and ancillary test and treatment modalities. In this review article, we did a medline search with key words 'uveitis' and 'India', and selectively incorporated articles showing the evolution of this sub-speciality in India.

Anterior segment involvement in vitreoretinal lymphoma: clinical manifestations, molecular findings and in vivo confocal microscopy

BACKGROUND

Intermediate and posterior manifestations of vitreoretinal lymphoma (VRL) are well characterised. However, there is limited information on anterior segment involvement in VRL. This study aimed to describe the anterior manifestations of VRL, and their association with molecular testing.

METHODS

Retrospective analysis of patients with biopsy-proven VRL. Study variables included anterior segment manifestations, findings from slit-lamp photos and in vivo confocal microscopy (IVCM) when available. MYD88 L265P mutation and cytology in the aqueous humour, retinal and systemic findings were also analysed.

RESULTS

The analysis included 108 eyes of 55 VRL patients. Anterior segment involvement was present in at least one visit in 55 eyes (51%) of 33 patients (60%); it included keratic precipitates (dendritiform with branching and irregular margins in 33 eyes, dust-like in 16 eyes and large granulomatous in 12 eyes), cells in the anterior chamber (51 eyes) and posterior synechiae (2 eyes). IVCM was available for 41 eyes and showed different morphologies of keratic precipitates, including floral, spikes and mulberry patterns (66%, 56% and 20%, respectively). MYD88 L265P mutation in the aqueous humour was detected in 10/21 (48%) eyes with no anterior segment involvement and 24/37 (65%) eyes with anterior segment involvement.

CONCLUSIONS

Anterior segment manifestations are often present in VRL and include dendritiform and dust-like keratic precipitates. IVCM in VRL can identify different patterns associated with keratic precipitates. MYD88 L265P mutation in the aqueous humour of VRL patients can also be found in eyes without significant anterior segment involvement.

Viral Anterior Uveitis: A Practical and Comprehensive Review of Diagnosis and Treatment

Anterior uveitis is the most common type of uveitis worldwide. The etiologies of anterior uveitis can be divided into infectious and non-infectious (idiopathic, autoimmune, autoinflammatory, trauma, and others). The viral pathogens most commonly associated with infectious anterior uveitis include Herpes Simplex Virus, Varicella-Zoster Virus, Cytomegalovirus, and Rubella Virus. Other emerging causes of viral anterior uveitis are West Nile Virus, Human-Immunodeficiency Virus, Epstein-Barr Virus, Parechovirus, Dengue Virus, Chikungunya Virus, and Human Herpesvirus type 6,7, and 8. Early recognition allows prompt management and mitigates its potential ocular complications. This article provides an updated literature review of the epidemiology, clinical manifestations, diagnostic tools, and treatment options for viral anterior uveitis.

Reactivation of varicella zoster infection presenting as acute retinal necrosis post COVID 19 vaccination in an Asian Indian male

PURPOSE

To present the clinical features of a rare case of varicella zoster infection following one dose of Coronavirus Disease 2019 (COVID-19) vaccination in an elderly Asian Indian male.

METHODS

Retrospective observational case report.

RESULTS

A 71-year-old gentleman presented to us with complaints of reduced vision associated with redness and pain in his right eye for 1 week. On examination he revealed a right eye pan uveitis picture with circumcorneal congestion, multiple fine keratic precipitates, anterior chamber cells and flare, vitritis and widespread areas of acute retinal necrosis. His left eye was within normal limits. Ten days prior to the presentation he had received the first dose of COVID-19 vaccine following which he had developed fever for 2 days that preceded the red eye. The patient's aqueous sample tested positive for varicella zoster virus (VZV) by nested polymerase chain reaction (PCR) method. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in reverse transcriptase polymerase chain reaction (RT-PCR) assay from the aqueous and also from the nasopharyngeal swab was negative.

CONCLUSION AND SIGNIFICANCE

To the best of our knowledge this is the earliest description of a case that has a viral reactivation following COVID-19 vaccination. Elderly people with pre-existing comorbidities, may be at a risk of both primary coronavirus infection and unconceivable risk of aberrant immune reactions leading to a different virus infection or reactivation need to be kept in mind. We present a possible link between SARS-CoV-2 virus vaccination and varicella zoster reactivation in this patient.

In Vivo Confocal Microscopy of Keratic Precipitates in Vitreoretinal Lymphoma

PURPOSE

To investigate the morphological features of keratic precipitates (KPs) with in vivo confocal microscopy (IVCM) in vitreoretinal lymphoma (VRL).

METHODS

Patients with biopsy-proven VRL were reviewed, and 12 patients (16 eyes) with KPs examined by IVCM were included.

RESULTS

Five distinct KP morphologies on IVCM were observed: dendritic, nibbling, linear, globular, and stippled. Dendritic KPs were discovered in 9 eyes (56.3%), with a hyperreflective core and multiple thin pseudopodia. Nibbling KPs were found in 8 eyes (50.0%), featuring irregularly hyperreflective borders and a mottled reflective interior. Linear, stippled, and globular KPs were self-explanatory and affected nearly all eyes. Globular KPs seem to be formed by hyperreflective cells with large nuclei and prominent nucleoli, similar to atypical lymphocytes in vitreous cytology.

CONCLUSIONS

IVCM could provide more insight into the morphological traits of KPs than clinical observation, highlighting its potential for identifying VRL involving the anterior segment.

Ocular Manifestations of Chikungunya Infection: A Systematic Review

The Chikungunya virus (CHIKV) can cause long lasting symptoms and manifestations. However, there is little information on which ocular ones are most frequent following infection. We performed a systematic review (registered in the International Prospective Register of Systematic Reviews; no CRD42020171928) to establish the most frequent ocular manifestations of CHIKV infection and their associations with gender and age. Articles published until September 2020 were selected from PubMed, Scielo, Cochrane and Scopus databases. Only studies with CHIKV-infected patients and eye alterations were included. Reviews, descriptive studies, or those not investigating the human ocular manifestations of CHIKV, those with patients with other diseases and infections, abstracts and studies without relevant data were excluded. Twenty-five studies were selected for inclusion. Their risk of bias was evaluated by a modified Newcastle-Ottawa scale. The most frequent ocular symptoms of CHIKV infection included ocular pain, inflammation and reduced visual acuity, whilst conjunctivitis and optic neuritis were the most common manifestations of the disease. These occurred mostly in individuals of 42 ± 9.5 years of age and woman. The few available reports on CHIKV-induced eye manifestations highlight the need for further research in the field to gather more substantial evidence linking CHIKV infection, the eye and age/gender. Nonetheless, the data emphasizes that ocular alterations are meaningful occurrences of CHIKV infection which can substantially affect quality of life.

In vivo Confocal Microscopic Evaluation of Corneal Changes in Acute Endothelial Rejection

Purpose

To evaluate the microstructural corneal changes during acute endothelial graft rejection and following treatment using in vivo confocal microscopy (IVCM).

Methods

Patients with a clinical diagnosis of severe acute endothelial graft rejection following penetrating keratoplasty were included in this study. IVCM was performed on the 1^st day the patient presented with rejection signs and at the time of clinical resolution.

Results

Twenty-three patients were included in this study. Inflammatory cells appeared as dendritic cells (DCs) and less frequently, as non-DCs in basal epithelial and subbasal areas. Activated keratocytes (AKs) (type 1: large cells with visible cytoplasmic processes; type 2: elongated and spindle-shaped keratocytes) were visible in acute phase. Following resolution, type 1 AKs considerably reduced, but type 2 cells were more often persisted. Multiple types of keratic precipitates (KPs) were also visible in acute phase which resolved following resolution of rejection.

Conclusions

Acute graft rejection was associated with an increase in the number of DCs, activation of keratocytes, and aggregation of various types of KPs. Inflammatory process subsided in almost all cases, but the IVCM changes did not return to normal early after clinical resolution of rejection.

Structural Endpoints and Outcome Measures in Uveitis

Most uveitis entities are rare diseases but, taken together, are responsible for 5-10% of worldwide visual impairment which largely affects persons of working age. As with many rare diseases, there is a lack of high-level evidence regarding its clinical management, partly due to a dearth of reliable and objective quantitative endpoints for clinical trials. This review provides an overview of available structural outcome measures for uveitis disease activity and damage in an anatomical order from the anterior to the posterior segment of the eye. While there is a multitude of available structural outcome measures, not all might qualify as endpoints for clinical uveitis trials, and thorough testing of applicability is warranted. Furthermore, a consensus on endpoint definition, standardization, and "core outcomes" is required. As stipulated by regulatory agencies, endpoints should be precisely defined, clinically important, internally consistent, reliable, responsive to treatment, and relevant for the respective subtype of uveitis. Out of all modalities used for assessment of the reviewed structural outcome measures, optical coherence tomography, color fundus photography, fundus autofluorescence, and fluorescein/indocyanine green angiography represent current "core modalities" for reliable and objective quantification of uveitis outcome measures, based on their practical availability and the evidence provided so far.

Keratic Precipitates: The Underutilized Diagnostic Clue

The morphology of keratic precipitates (KPs) may yield important diagnostic clues. However, KPs have not been described in a standardized manner and the traditional classification of granulomatous or non-granulomatous KPs is not helpful in differentiating infectious from noninfectious uveitis. A granulomatous uveitis may initially appear non-granulomatous. We suggest three ways to examine KPs that may aid in differentiating the infectious from noninfectious etiologies. The first method is the in vivo confocal microscopy (IVCM) description and classification of KPs, in which the "non-granulomatous" subset of dendritiform and infiltrative KPs should be differentiated from smooth-rounded KPs and globular KPs which are "granulomatous." The second and third clues are the distribution and color of the KPs. KPs that extend beyond the midline may suggest an infective cause, and fresh pigmented KPs suggest a viral cause. Careful examination of the KPs may immediately reveal the clues to the diagnosis, minimizing unnecessary tests and costs.

Role of Ocular Imaging in Diagnosis and Determining Response to Therapeutic Interventions in Posterior and Panuveitis

ABSTRACT

This review provides a comprehensive description and careful interpretation of various ocular imaging techniques to visualize the different ocular structures in posterior and panuveitis. This can help in the diagnosis, follow-up, and monitoring the response to treatment in patients with different posterior and panuveitic entities.

Floral Pattern of Keratic Precipitates in Vitreoretinal Lymphoma on In Vivo Confocal Microscopy

PURPOSE

To describe the morphological patterns of keratic precipitates (KPs) in vitreoretinal lymphoma (VRL) using in vivo confocal microscopy (IVCM).

METHODS

Six eyes of three biopsy-proven VRL patients were included. KPs were identified and analyzed on IVCM.

RESULTS

On examination, pigmented KPs in four eyes, white central KPs in two eyes and anterior chamber cells with flare in six eyes and pseudo hypopyon in one eye were identified. A typical floral pattern of KPs on IVCM was noted in all eyes. Three eyes each showed the complete and incomplete floral patterns, respectively. Resolution of KPs on IVCM was noted after chemotherapy.

CONCLUSION

In addition to the routinely used clinical and imaging markers like the visual acuity, presence of lymphomatous cells in the vitreous and optical coherence tomography findings, the presence and appearance of KPs on IVCM can also be considered as a useful, diagnostic and treatment monitoring marker in VRL.

Corneal endothelium in paediatric patients with uveitis: a prospective longitudinal study

PURPOSE

To study the longitudinal effect of anterior chamber inflammation on the corneal endothelium in children.

METHODS

In this prospective longitudinal observational study, children (aged <18 years) with anterior chamber inflammation and those at risk of developing uveitis due to juvenile idiopathic arthritis (JIA) were included. Changes in central endothelial cell density (ECD) and morphological variables were determined by non-contact specular microscopy, and their correlations with uveitis activity and surgical interventions were analysed.

RESULTS

Ninety-nine eyes of 99 children (mean age (±SD): 10.0±4.1 years) with a history of anterior chamber inflammation were recruited. Mean follow-up was 12.3±3.5 months. Eleven children, who were under surveillance but had not developed JIA-associated uveitis were included as controls. While there were no significant differences in mean ECD between controls and subjects without prior surgery (group 1) at all time points, those who had prior ophthalmic surgery (group 2) displayed significantly lower ECD than the controls at recruitment (p=0.002) and at follow-up (p=0.004). However, longitudinal ECD assessments did not show significant changes in either group (group 1, p=0.07, group 2, p=0.54). On regression analysis, once the patient's age was adjusted for, only the occurrence of intraocular procedures during the study (r=0.43, adjusted p=0.03) was associated with a significant annual rate of ECD loss.

CONCLUSION

During the study period, longitudinal ECD changes among children with uveitis were associated with intraocular surgery for uveitis-related complications but not uveitis activity. By reducing the need for surgical intervention, the corneal endothelium in these children may be preserved.

In vivo confocal microscopy of the inflamed anterior segment: A review of clinical and research applications

In vivo confocal microscopy (IVCM) allows non-invasive imaging of the living human cornea, specifically enabling the detection of immune cells in the healthy and diseased ocular anterior segment. Studies using IVCM have provided insight into the effects of contact lens wear on corneal Langerhans cell density and morphology, and the effects of eye drops on conjunctiva-associated lymphoid tissue. IVCM has also been shown to be a useful adjunctive diagnostic tool in distinguishing infective and non-infective uveitis and in diagnosing atypical infective keratitis. In the research setting, this technology has enhanced our understanding of the role of inflammatory cells in corneal neuropathy and angiogenesis. In vivo-ex vivo correlation using animal models has helped overcome some of the difficulties in identifying cell type on IVCM images. As highlighted in this review, currently there are multiple established, and emerging, clinical and research applications for IVCM in the inflamed anterior segment.

Characteristics of Corneal Endotheliitis among Different Viruses by in Vivo Confocal Microscopy

Objectives: To explore the cellular morphological characteristics and changes in corneal endotheliitis among different viruses by in vivo confocal microscopy (IVCM).Methods: Corneal confocal images of 44 eyes of 44 patients with HSV, VZV, CMV and EBV corneal endotheliitis were studied retrospectively. Corneal confocal images of 44 normal eyes were used as controls.Results: The pathogens included cytomegalovirus (n = 20), herpes simplex virus (n = 8), varicella zoster virus (n = 10), and Epstein Barr virus (n = 6). There were no differences in the evaluated structures among the different viruses except for the lengths of the subbasal nerves and Langerhans cell densities. Deviations in endothelial cell layers were not significant among different viruses except for owl's eye morphology.Conclusion: ICVM can assist in diagnosing endotheliitis. The results demonstrate that changes in the cornea were not different among the various viruses except for owl's eye morphology, the lengths of the subbasal nerves and Langerhans cell densities.

Confocal scanning laser microscopy in patients with postoperative endophthalmitis

PURPOSE

To investigate alterations of corneal layers in eyes treated for acute postoperative endophthalmitis.

METHODS

In this retrospective, nonrandomized comparative study, eyes treated with 25 gauge pars plana vitrectomy (PPV) for acute post-cataract endophthalmitis (group A) were compared to eyes receiving uneventful cataract surgery (group B) and uneventful 25 gauge PPV for epiretinal membrane (group C). After a minimum follow-up of 8 months from last surgical procedure, laser scanning in vivo confocal microscopy (IVCM) was performed.

RESULTS

Twelve eyes for each group were recruited. Comparing study eyes with control eyes of group B and C, no statistical difference was found in corneal epithelial cell density (p = n.s.), in density of nerve fibers (p = n.s.), mean grade of nerve reflectivity (p = n.s.), mean grade of nerve tortuosity (p = n.s.), mean grade of anterior keratocyte activation (p = n.s.), and corneal endothelium cell density (p = n.s.), whereas a statistically higher mean grade of posterior keratocyte activation was found in group A (p < 0.01). Epithelial and endothelial corneal morphologies were graded as regular in all groups. Langerhans cells and corneal dendritic-shaped hyper-reflective endothelial deposits were found in group A. Both findings were absent in group B and C, and the difference was statistically significant (p < 0.01).

CONCLUSIONS

IVCM was a useful tool in the detection of microscopic chronic corneal abnormalities caused by postoperative endophthalmitis. These findings confirmed the presence of a subclinical chronic corneal inflammation localized to the posterior stroma that should be related to the infectious process. Future studies might clarify pathological processes in the acute phase of postoperative endophthalmitis.

In Vivo Laser Confocal Microscopy Using the HRT-Rostock Cornea Module: Diversity and Diagnostic Implications in Patients with Uveitis

PURPOSE

Keratic precipitates (KP) are a common feature of uveitis. We prospectively examined KP with the Heidelberg Retinal Tomograph II confocal laser scanning microscope and Rostock Corneal Module (HRT-RCM) to explore their diagnostic implications.

METHODS

Prospective, observational, multicenter study. HRT-RCM images were classified by two masked observers.

RESULTS

120 scans on 120 eyes from 110 subjects were included. The majority (N = 93) had non-infectious uveitis. Sixty eyes had active disease at scanning. Eight KP morphologies were defined. Agreement between the two masked graders was high (Kappa value across all categories = 0.81). Cluster and nodular KP were associated with active infectious uveitis (p < 0.01): patients with cluster KP (odds ratio [OR] = 3.03, 95% confidence interval [CI]: 1.43, 6.45) and nodular KP (OR = 3.89, 95% CI: 1.42, 10.65) were more likely to have infectious uveitis than those without.

CONCLUSIONS

Laser confocal microscopy of KP may have a role in determining between infectious and non-infectious uveitis.

Aqueous cell differentiation in anterior uveitis using Fourier-domain optical coherence tomography

PURPOSE

The differential diagnosis of a patient presenting with anterior uveitis is broad and can present a diagnostic challenge. In this study, we evaluate the characteristic findings of inflammatory cells on optical coherence tomography (OCT) both in vitro and in vivo.

METHODS

Blood from two healthy volunteers was prepared using standardized methods for cell sorting with a flow cytometer (FASCAria). Neutrophils, lymphocytes, monocytes, and red blood cells were placed in suspension and scanned with a 26-kHz Fourier-domain OCT system (RTVue) with 5-μm axial resolution. Custom software algorithms were used to identify cells based on their reflectance distribution. These algorithms were then applied to OCT images obtained from uveitis patients with active anterior chamber inflammation.

RESULTS

On OCT images the cells appeared as hyperreflective spots. In vitro, cell reflectance was statistically significantly different between all of the cell types (neutrophils, monocytes, lymphocytes, and red blood cells, P < 0.001, Mann-Whitney test). In vivo, the relationship between underlying disease and cell type imaged on OCT was highly statistically significant, with human leukocyte antigen (HLA)-B27-associated uveitis patients having a predominantly polymorphonuclear pattern on OCT and sarcoidosis and inflammatory bowel disease patients having a predominantly mononuclear pattern on OCT (P < 0.001, Fisher's exact test).

CONCLUSIONS

These in vitro and in vivo data demonstrate the potential of OCT to evaluate cells in the anterior chamber of patients noninvasively. Optical coherence tomography may be a useful adjunct to guide the diagnosis and treatment of ocular inflammatory conditions.

Viral anterior uveitis

PURPOSE OF REVIEW

With improvements in molecular diagnostics tests, viruses are increasingly being found to be associated with what was previously described as idiopathic anterior uveitis. This review presents the clinical features of viral anterior uveitis.

RECENT FINDINGS

Herpes simplex virus/varicella zoster virus (HSV/VZV) are important causes of anterior uveitis, but other viruses including cytomegalovirus (CMV) and rubella are also found in a significant number of cases. The various viral anterior uveitides have similar features and should be suspected in eyes with diffuse, fine, stellate keratic precipitates, iris atrophy or ocular hypertension. Acyclovir remains the mainstay of therapy in HSV/VZV infections. CMV responds to ganciclovir, but the relapse rate is high and prolonged therapy may be required. Cataract and glaucoma are the main complications of viral anterior uveitis requiring appropriate management.

SUMMARY

There is considerable overlap between clinical manifestations of the different viral anterior uveitides as well noninfectious hypertensive anterior uveitis syndromes. Hence, corticosteroids should be used with caution in these eyes if virus diagnostic tests are not available.

In vivo confocal microscopic evaluation of keratic precipitates and endothelial morphology in Fuchs' uveitis syndrome

PURPOSE

To evaluate the endothelial cell layer in patients with Fuchs' uveitis syndrome (FUS) with respect to the type and distribution of keratic precipitates (KP), endothelial cell morphology, and endothelial cell density (ECD), using in vivoconfocal microscopy (IVCM).

METHODS

Forty eyes of 40 patients (mean age of 32.2 ± 12.5 years) with the clinical diagnosis of FUS were evaluated with IVCM (Confoscan 3.0, Vigonza, Italy). KP were classified as type I (small, round), type II (stippled), type III (dendritiform), and type IV (globular). When >1 KP type was present, differentiation between the predominant and less frequent KP was made as 'primary' and 'secondary'. ECD was measured and compared with age-matched 60 control subjects. Endothelial blebs were classified as small (3-10 μm) or large (>10 μm).

RESULTS

In 36 (90.0%) cases with FUS, more than one KP type was observed with IVCM. Type III (dendritiform) KP was the most frequently observed primary KP type (85.0%), followed by type II (stippled) KP (15.0%). Secondary KP included type II (58.3%), type IV (globular) (27.8%), and type III (13.9%). The mean endothelial cell density of eyes with FUS (2588 ± 396 cells/mm(2)) was significantly lower than that of control subjects (2930 ± 364 cells/mm(2)) (t-test; P<0.001). Eyes with FUS had lower proportion of hexagonal cells and higher percentage of polymegethism compared with the uninvolved contralateral eyes. Endothelial blebs (21 small, 16 large blebs) were observed in 37 (92.5%) eyes.

CONCLUSIONS

FUS is characterized by dendritiform KP and is associated with decreased ECD and altered endothelial cell morphology.