Study of corneal copper deposits in Wilson's disease by in vivo confocal microscopy

Eye Involvement in Wilson’s Disease: A Review of the Literature

Wilson’s disease (WD) is an autosomal recessive genetic disorder due to a mutation of the ATP7B gene, resulting in impaired hepatic copper excretion and accumulation in various tissues. Ocular findings are one of the hallmarks of the disease. Many ophthalmological manifestations have been described and new techniques are currently available to improve their diagnosis and to follow their evolution. We have performed a systematic PubMed search to summarize available data of the recent literature on the most frequent ophthalmological disorders associated with WD, and to discuss the newest techniques used for their detection and follow-up during treatment. In total, 49 articles were retained for this review. The most common ocular findings seen in WD patients are Kayser–Fleischer ring (KFR) and sunflower cataracts. Other ocular manifestations may involve retinal tissue, visual systems and eye mobility. Diagnosis and follow-up under decoppering treatment of these ocular findings are generally easily performed with slit-lamp examination (SLE). However, new techniques are available for the precocious detection of ocular findings due to WD and may be of great value for non-experimented ophthalmologists and non-ophthalmologists practitioners. Among those techniques, anterior segment optical coherence tomography (AS-OCT) and Scheimpflug imaging are discussed.

Investigation of corneal topographic and densitometric properties of Wilson's disease patients with or without a Kayser-Fleischer ring

BACKGROUND

To investigate the topographic measurements and densitometry of corneas in Wilson's disease (WD) patients with or without a Kayser-Fleischer ring (KF-r) compared to healthy individuals.

METHODS

This cross-sectional study included 20 WD patients without a KF-r (group I), 18 WD patients with a KF-r (group II), and 20 age-matched controls (group III). The Pentacam high resolution imaging system is used to determine corneal topographic measurements and densitometry.

RESULTS

Mean age for groups I, II and III was 25.40 ± 6.43 years (14-36 years), 25.38 ± 6.96 years (16-39 years), 23.60 ± 6.56 years (17-35 years), respectively (P = 0.623). There was no significant difference between the groups in terms of the anterior corneal densitometry values (P > 0.05), while the 6-10 mm and 10-12 mm mid stroma and the 2-6 mm, 6-10 mm, and 10-12 mm posterior corneal densitometry values in group II were significantly higher than those in groups I and III (for all values, P <  0.05). However, the 10-12 mm posterior corneal densitometry values in group I were also significantly higher than those in group III (P = 0.038). The central corneal thickness (CCT), thinnest corneal thickness (tCT), and corneal volume (CV) values in groups I and II were significantly lower than those in group III (for CCT values, P = 0.011 and P = 0.009; for tCT values, P = 0.010 and P = 0.005; for CV values, P = 0.043 and P = 0.029).

CONCLUSION

In WD patients with a KF-r, corneal transparency decreased in the peripheral posterior and mid stromal corneal layers; for these patients, corneal transparency may be impaired not only in the peripheral cornea but also in the paracentral cornea.

Anterior segment optical coherence tomography (AS-OCT) as a new method of detecting copper deposits forming the Kayser-Fleischer ring in patients with Wilson disease

PURPOSE

Kayser-Fleischer ring pathognomonic for Wilson disease (WD) is formed of corneal copper deposits present predominantly within the anterior chamber angle at the Schwalbe's line. The slit-lamp assessment commonly used as a standard of care cannot detect them early enough, as the angle view is obscured by the corneal limbus. The aim of the research was to evaluate the anterior segment optical coherence tomography (AS-OCT), as objective diagnostic assessment of copper deposits forming KF ring in patients with WD.

METHODS

Twenty-nine subjects (17 women) and twenty-nine controls (14 women) were enrolled and underwent slit lamp and AS-OCT assessment.

RESULTS

Kayser-Fleischer ring was not detected - either with a slit lamp or with AS-OCT - in any of the controls. Fifteen subjects presenting without KF ring at a slit-lamp examination were found to have a KF ring when examined with AS-OCT (p < 0.001), which confirms improved accuracy of AS-OCT, as compared to the slit-lamp examination.

CONCLUSION

Our results support AS-OCT as a diagnostic procedure to offer better objectivity and accuracy as compared to a slit-lamp examination, both at the diagnostic stage and when monitoring changes in KF ring during medical therapy to assess its efficacy and patient compliance.

Assessment of corneal and lens clarity in children with Wilson disease

PURPOSE

To investigate the effect of copper accumulation on corneal and lens clarity in children with Wilson disease (WD) compared to healthy children.

METHODS

This multicenter cross-sectional study included 24 subjects with WD and 25 age-matched controls. Clinical and laboratory characteristics of the WD subjects were recorded. The Pentacam HR imaging system was used both for lens densitometry and corneal densitometry.

RESULTS

Corneal densitometry values were higher in the posterior 6-10 mm (P = 0.021), posterior 10-12 mm (P < 0.001), posterior total diameter (P = 0.037), total thickness 10-12 mm (P = 0.032), and total thickness 6-10 mm zones and layers (P = 0.040) in the WD eyes than in control eyes. The lens densitometry values of zone 1 were higher in WD eyes (P < 0.001). There was a significant relationship between corneal densitometry values in the posterior 10-12 mm zones (P = 0.012; r = 0.527) and the duration of WD and liver copper content (P = 0.016; r = 0.507). A statistically significant correlation was also detected between lens densitometry values in zone 1 and WD duration (P = 0.018; r = 0.426).

CONCLUSION

In this study cohort, children with WD had decreased corneal and lens clarity even in cases without Kayser-Fleischer rings and sunflower cataracts. Densitometry measurements using Scheimpflug imaging provided detection of corneal and lens involvement in the early stages of WD.

Imaging Kayser-Fleischer Ring in Wilson Disease Using In Vivo Confocal Microscopy

PURPOSE

This study analyzes images of Kayser-Fleischer (K-F) rings in patients with Wilson disease (WD) using in vivo confocal microscopy (IVCM) and explores whether IVCM can be a useful clinical tool in facilitating the diagnosis and characterization of K-F rings.

METHODS

One hundred four eyes of 52 patients with WD and K-F rings (K-F group) and 52 normal eyes of 52 age- and gender-matched control subjects (control group) were enrolled in the study. Both K-F and control groups consisted of 29 male patients and 23 female patients. IVCM imaging was performed, and images of the peripheral Descemet membrane were analyzed.

RESULTS

All patients in K-F group showed abnormal patterns in the peripheral Descemet membrane from IVCM images. These abnormalities can be generally divided into 3 types: patchy, stripy, and spotty patterns. Each patient may have a combination of these patterns, with patchy pattern being most prevalent (100%), whereas stripy and spotty patterns are present in 30% to 40% of the K-F rings. Notably, these patterns are not correlated with other systematic symptoms of WD.

CONCLUSIONS

IVCM images can be used as an objective clinical diagnostic tool to facilitate the identification of K-F rings and the diagnosis of WD.

Anterior segment optical coherence tomography to look for Kayser-Fleischer rings

Ophthalmologists usually use slit lamp biomicroscopy to look for Kayser-Fleischer rings in Wilson's disease; anterior segment optical coherence tomography is a new alternative to identify the characteristic hyper-reflective layer in the deep corneal periphery at the level of Descemet's membrane. This method allows non-ophthalmologists to look for and to quantify Kayser-Fleischer rings.