Classification of secondary corneal amyloidosis and involvement of lactoferrin

Purpose: To classify secondary corneal amyloidosis (SCA) by its clinical appearance, to analyze the demographics of the patients, and to determine the involvement of lactoferrin. Design: Retrospective, observational, noncomparative, multicenter study. Participants: Twenty-nine eyes of 29 patients diagnosed with SCA by corneal specialists at 9 ophthalmologic institutions in Japan were studied. Methods: The clinical appearance of SCA was determined by slit-lamp biomicroscopy and was classified into 3 types. The demographics of the patients, for example, age, gender, and the duration of the basic disease (trichiasis, keratoconus, and unknown), were determined for each clinical type. Surgically excised tissues were stained with Congo red and antilactoferrin antibody. The postoperative prognosis also was determined. Main Outcome Measures: Clinical appearance of the 3 types of SCA, along with the gender, age, and duration of the basic diseases were determined. Results: Classification of SCA into 3 types based on clinical appearance found 21 cases with gelatinous drop-like dystrophy (GDLD)-like appearance (GDLD type), 3 cases with lattice corneal dystrophy (LCD)-like appearance (LCD type), and 5 cases with the combined type. Patients with the GDLD type were younger (average age: 40.9 years for the GDLD type, 74.3 years for the LCD type, and 46.8 years for the combined type), predominantly women (85.7% for the GDLD type, 33.3% for the LCD type, and 60% for the combined type), and had the basic disease over a longer time (average duration: 22.1 years for the GDLD type, 14.0 for the LCD type, and 11.4 for the combined type). The distribution of the basic diseases (trichiasis vs. keratoconus vs. unknown) was not significantly different for each type. Surgical treatments, for example, phototherapeutic keratectomy, lamellar keratoplasty, and simple keratectomy, resulted in a good resolution in all surgically treated cases. One subject dropped out of the study. Spontaneous resolution was seen in one subject after epilation of the cilia. Amorphous materials in the excised tissues showed positive staining results by Congo red and by antilactoferrin antibody. Conclusions: Secondary corneal amyloidosis can be classified into 3 clinical types based on its clinical appearance. Larger numbers of females and lactoferrin expression were seen in all 3 types. Financial Disclosure(s): The author(s) have no proprietary or commercial interest in any materials discussed in this article.