[New international classification of corneal dystrophies (CD)]

Descemet Membrane Endothelial Keratoplasty (DMEK) for Severe Verrucous Posterior Polymorphous Corneal Dystrophy with Uncommon Clinical and Ultrastructural Findings

PURPOSE

To report a case of severe verrucous posterior polymorphous corneal dystrophy (PPCD) and cataract, which was treated with Descemet membrane endothelial keratoplasty (DMEK) and simultaneous cataract surgery as a triple procedure (Triple-DMEK).

METHODS

A 62-year-old female patient presented to our department for co-evaluation of advanced PPCD with cataract and progressive light sensitivity in both eyes. The clinical examination demonstrated unusual clinical findings with prominent verrucous lesions on the posterior surface of the cornea without corneal decompensation. We performed a Triple-DMEK in case of simultaneous cataract. The corneal tissue was examined by light and transmission electron microscopy.

RESULTS

Intraoperatively, it was difficult to remove the verrucous structures completely after classical descemetorhexis. Light microscopic examination demonstrated epithelium-like transformation of the corneal endothelium by immunostaining (cytokeratin AE1/3 staining). Transmission electron microscopy revealed thickening of Descemet's membrane (18.5 to 30.0 µm). The anterior banded layer had a normal structure and was slightly thickened (3.5 to 5.5 µm). A normal posterior non-banded layer (PNBL) was observed but thinned (2.5 to 4.0 µm) or missing. It was followed by an altered PNBL with abnormal fibrillary inclusions, which was strongly and variably thickened (11.0 to 24.5 µm). The corneal endothelium was degenerated, partially absent, and epithelial-like altered. The nodular lesions were found to consist of a few degenerated cells that were embedded in an amorphous extracellular matrix interspersed with collagen fibers, which were not arranged in regular lamellae, forming the corneal stroma. The occurrence of pigment granules among the cellular debris suggested that the cells were endothelial cells. The corrected distance visual acuity improved from 20/50 to 20/30 in the right eye (+ 0.00/- 1.75/157°) and from 20/60 to 20/30 in the left eye (+ 0.00/- 1.75/33°), with significant improvement in light sensitivity.

CONCLUSION

The clinical and ultrastructural findings seem to be an unusual variant of the typical characteristic appearance of a PPCD. This case demonstrates that Triple-DMEK is feasible even in very advanced dystrophic changes of the posterior corneal surface, with good morphological and functional results.

Simultaneous transplantation of limbal stem cells may reduce recurrences of granular dystrophy after corneal transplantation: 2 long-term case reports

To present 2 cases with long-term relapse-free intervals only after limbo-keratoplasty but not after conventional penetrating keratoplasty in granular dystrophy.Retrospective review of the patient charts and photographs taken during long-term follow-up of 2 cases with granular dystrophy, in which 1 eye received penetrating keratoplasty and the fellow eye received penetrating limbo-keratoplasty.In the first patient, 1 eye showed extensive recurrence of granular deposits 17 years after penetrating keratoplasty was performed while in the second eye two-thirds of the corneal transplant adjacent to the transplanted limbal area remained clear 12 years after the limbo-corneal transplant. In the second patient, 1 eye showed no signs of recurrence 5 years after limbo-keratoplasty, whereas a recurrence of granular corneal deposits occurred 18 months after surgery in the fellow eye.These cases show that the simultaneous transplantation of healthy donor limbus when performing penetrating keratoplasty may prolong recurrence in granular corneal dystrophy. Although we were unable to prove it on the molecular level, these clinical courses may support the hypothesis that a limbal transplant helps prevent a recurrence.

Peripheral hypertrophic subepithelial corneal degeneration presenting with bilateral nasal and temporal corneal changes

PURPOSE

To characterise the history, clinical and histopathological features of patients with bilateral nasal and temporal peripheral hypertrophic subepithelial corneal degeneration in a German population.

METHODS

A detailed ophthalmological and dermatological history and clinical findings were recorded of nine patients with bilateral simultaneous nasal and temporal peripheral corneal degeneration from two centers in Germany. Excised tissues were studied by histopathology, immunohistochemistry, and transmission electron microscopy.

RESULTS

Foreign body sensation and need of artificial tear substitutes were the only symptoms reported regularly. Schirmer's and Jones-test were normal in all, but fluorescein break-up time of >10 s was found in five eyes of four patients. Best corrected visual acuity was reduced only under glare conditions. Corneal topography revealed irregular astigmatism in 13 of 14 eyes. Follow-up median time was 35 months. Most cases were stable within the follow-up period. Light and electron microscopy revealed the findings of superficial vascularised corneal hypertrophic scars, oxytatlan fibers, and discontinued Bowmans layer.

CONCLUSION

In this series of German patients with peripheral hypertrophic subepithelial corneal degeneration, the changes were predominantly located in the palpebral aperture and often present in both eyes. No associated surface disease could be established in this study. Light and transmission electron microscopy showed histological features that are similar to Salzmann's corneal changes without any inflammation. We hypothesise that light exposure and a localised limbal insufficiency could be involved in the pathogenesis.

[Discrete bilateral corneal deposits in a young woman]

A 17-year-old asymptomatic girl presented with discrete bilateral deposits in the superficial corneal stroma. The diagnosis of very early and in this form as yet undescribed manifestation of Schnyder's corneal dystrophy, was only possible based on the family history.