[Floppy eyelid syndrome: light and electron microscopy studies]

Effects of collagen crosslinking on porcine and human tarsal plate

BACKGROUND

Floppy eyelid syndrome is a disorder in which the tarsal plate is easily distensible and is currently treated with conservative or surgical measures. Human tarsal plate contains type I collagen, which is crosslinked in corneal tissue as a treatment for keratoconus. We hypothesized that collagen crosslinking would similarly stiffen tarsal plate tissue and investigated this in porcine and human tarsal plate specimens.

METHODS

Riboflavin-sensitized porcine and human tarsus samples were irradiated with ultraviolet-A light. Porcine experiments were analyzed with gross photographs, anterior segment optical computed tomography (AS-OCT) imaging, and tensile testing. A prospective study of human tarsus was performed on samples from patients undergoing wedge resection for floppy eyelid syndrome and was analyzed with AS-OCT and tensile testing.

RESULTS

73 porcine adnexa and 9 patients (16 eyelids) who underwent wedge excision were included in the study. Grossly, greater stiffness was observed in crosslinked porcine tissue. AS-OCT imaging in porcine tissue showed a distinct hyperreflective band in crosslinked specimens whose area and intensity increased with longer treatment time (P = 0.003); this band was also visible in crosslinked human specimens. Tensile testing was performed, but results were not statistically significant.

CONCLUSIONS

AS-OCT imaging, which has not been previously described for tarsal plate, showed a characteristic change in crosslinked porcine and human specimens. Tissue stiffness was increased grossly, but changes in tensile properties were not statistically significant. Further study is warranted to determine relevance as a potential treatment for floppy eyelid syndrome.

[Floppy eyelid syndrome : A frequently underdiagnosed entity of interdisciplinary importance]

Clinically, the floppy eyelid syndrome is a frequent but underdiagnosed condition. This clinical phenotype is characterized by an extreme laxity of the eyelid, which is enlarged and has a rubber-like structure in combination with a pronounced hyperelastic tarsus. When looking down, minimal vertical tension can trigger spontaneous eversion of the upper eyelid leading to chronic papillary conjunctivitis. This syndrome usually affects older, adipose men who also suffer from sleep apnea and metabolic syndrome. Due to the resistance of chronic papillary conjunctivitis to conservative treatment, surgical treatment is often necessary; however, due to the frequent association between floppy eyelid syndrome, sleep apnea and metabolic syndrome a collaborative interdisciplinary approach is necessary.

Floppy eyelid syndrome

PURPOSE OF REVIEW

Although floppy eyelid syndrome causes significant ocular symptoms and morbidity, the condition is often underdiagnosed. This review will highlight diagnostic features of the condition, emphasizing recent advances in the understanding of its pathophysiology. Current therapeutic strategies and surgical techniques are discussed.

RECENT FINDINGS

Current concepts regarding the underlying pathophysiology of floppy eyelid syndrome revolve around upregulation of elastin degrading enzymes and mechanical factors. Together, these forces cause instability of the eyelid scaffold, resulting in eyelid malposition and ocular symptoms. Newer surgical treatments aim to preserve tarsus to improve eyelid stability and position.

SUMMARY

Floppy eyelid syndrome--an underdiagnosed condition--produces significant ocular morbidity. Symptoms range from occasional redness and irritation to corneal ulcer. Diagnosis is based on ocular signs, including easy or spontaneous eversion of the upper eyelids in conjunction with conjunctivitis and keratitis. The condition, associated with body mass index and obstructive sleep apnea, should be suspected in any obese patient with a chronic red and tearing eye. Treatment consists of supportive measures such as ocular lubrication, eyelid taping or a shield, and surgery to address horizontal laxity and redundant eyelid tissues.

Klassifikation der Erkrankungen der Augenoberfl�che

The ocular surface consists of the lid margin, conjunctiva and cornea which together with the tear system represent a functional entity. The diagnosis of ocular surface disease can be very difficult due to the similarity of various disease entities. The classification should be made on the pathological and pathophysiological characteristics of ocular surface disease. The first part of the classification comprises diseases of the lid margin, the tear system as well as diseases of the conjunctiva. Both the clinical presentation as well as the underlying pathophysiological and pathological characteristics of the most important ocular surface diseases are reviewed.

Histopathologic features of the floppy eyelid syndrome. Involvement of tarsal elastin

PURPOSE

Patients with the floppy eyelid syndrome have chronic papillary conjunctivitis with easily everted upper eyelids and a soft, pliant upper tarsus. The purpose of this study is to describe the clinical features and the histopathologic correlate in a group of patients with floppy eyelid syndrome.

METHODS

The authors examined eight patients with floppy eyelid syndrome, four of whom underwent surgical management with horizontal eyelid shortening. Eyelid tissue from these patients was examined using light microscopy, electron microscopy, and immunohistochemistry and compared with controls with unrelated eyelid or orbital disorders.

RESULTS

Clinical findings included obesity or eye rubbing, lash ptosis, and, less commonly, blepharoptosis. Two patients had documented sleep apnea with abnormal sleep electroencephalogram. Light microscopy of the surgical specimens showed chronic conjunctival inflammation, papillary conjunctivitis, and meibomian gland abnormalities, including granuloma formation. Verhoeff's modified elastin stain demonstrated a marked decrease in the amount of elastin fibers in tarsus from patients with floppy eyelid syndrome compared with controls. Immunohistochemical staining for elastin also showed a marked decrease of tarsal elastin in floppy eyelid patients compared with controls. In contrast, immunohistochemical stains showed that the distribution of collagen types I and III was similar between patients with floppy eyelid syndrome and controls. Electron microscopy demonstrated that tarsal collagen was comparable in patients and controls, and that there was a reduced amount of tarsal elastin in floppy eyelid syndrome compared with controls.

CONCLUSIONS

These findings demonstrate that tarsal elastin is decreased in the floppy eyelid syndrome, which may contribute to the laxity of the tarsus in this disorder.