Journal List > J Korean Ophthalmol Soc > v.55(4) > 1009931

Lim, Kim, Chun, and Kim: The Difference in Filaments between Corneal Occlusion and Keratoconjunctivitis Sicca



To examine histopathological findings of filamentary keratitis due to corneal occlusion.


We analyzed filamentary keratitis in 11 eyes with corneal occlusion due to blepharospasm, ptosis and paralytic strabismus, 11 eyes with keratoconjunctivitis sicca, and 13 eyes with both corneal occlusion and keratoconjunctivitis sicca. The following protocols were used for filament analyses: slit lamp examination for counting filament numbers, impression cytology for grading mucin content, and histopathology (hematoxylin and eosin staining) and immunohistochemistry (with AE1/AE3, MUC1, 5AC, 16) for histological analysis.


Slit lamp biomicrosopy showed a significantly smaller number of filaments in the corneal occlusion group (11 eyes, 2.7 ± 1.4) than the keratoconjunctivitis sicca group (11 eyes, 5.1 ± 2.2, p = 0.009). In impression cytology, the standard photograph grade of mucin content was significantly higher in the corneal occlusion group (2.7 ± 0.9) than the keratoconjunctivitis sicca group (1.9 ± 0.8, p = 0.034). On pathological exam, filaments showed a central filament with peripheral mucin. The central filaments were composed of core and cortex, and the core contained multiple deformed nuclei. However, the cortex was not stained by AE1/AE3, MUC1, 5AC, 16.


Filamentary keratitis due to corneal occlusion showed a smaller number of filaments and higher mucin content than filamentary keratitis induced by keratoconjunctivitis sicca and should be considered during treatment.


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Figure 1.
Standard photographs of mucin debridement amount. (A) Grade I: filament (black arrow) without mucin debridement. (B) Grade II: filaments with scanty mucin (red arrow) debridement. (C) Grade III: filament with moderate amount of mucin debridement (D) Grade IV: filaments with large amount of mucin debridement (PAS stain, ×100).
Figure 2.
The number of filaments observed on silt lamp examination. The corneal occlusion group shows signigicantly less number of filaments than other groups (p < 0.05). KCS = keratoconjunctivitis sicca group; CO = corneal occlusion group. * Mann-Whitney U-test; p < 0.05 was considered statistically significant.
Figure 3.
The grade of mucin amount by standard photograph observed on impression cytology. The keratoconjunctivitis sicca group shows signigicantly less amount of mucin than other groups (p < 0.05). KCS = keratoconjunctivitis sicca group; CO = corneal occlusion group. * Mann-Whitney U-test; p < 0.05 was considered statistically significant.
Figure 4.
Photographs of various filiament forms examined by impression cytology. The presence of central fiber (red arrows) are commonly observed (A, B, C, D: PAS stain, ×40).
Figure 5.
Photographs obtained by impression cytology near the base of filaments. They show homogeneous cells without important nuclear alterations, with eosinophilic cytoplasm and a N:C ratio of 1:8 (arrow). In the base of filaments, there were metaplastic cells with large N:C ratio, meta-chromatic cytoplasm and frequent nuclear alterations such as twin-nuclei (arrow head) (A, B: PAS stain, ×200).
Figure 6.
Pathologic specimens stained with H & E. Central fibers were definitely confirmed (black arrows). The deformed nuclei were aligned like bricks within the central fibers (red arrows). The vicinity of the central fibers was composed of atypical substances with mucin and dead cells (A: ×400 longitudinal sectio; B: ×400 transverse section; C: ×1000 longitudinal section; D: ×1000 transverse section, H & E stain).
Figure 7.
In immunostaining, excluding the central fiber, the peripheral area is stained with MUC1 (A), MUC5AC (B), and MUC16 (C) (blue arrows). The core of central fibers is stained with the pan-cytokeratin marker AE1/AE3 (D) (red arrows), but the cortex of central fibers (yellow arrows) is not staind with MUC1, 5AC, 16 or AE1/AE3 (×400).
Table 1.
Demographics of study population
Demographics KCS KCS + CO CO Total
Total No. of eyes, n (%) 11 (31.4%) 13 (37.2%) 11 (31.4%) 35
Gender (n)        
  Male 6 5 5 16 (45.7%)
  Female 5 8 6 19 (54.3%)
Age (years) 58.4 ± 12.4 55.9 ± 13.5 55.9 ± 13.9 56.7 ± 12.9

Values are presented as mean ± SD unless otherwise indicated.

KCS = Keratoconjunctivitis sicca; CO = corneal occlusion; SD = standard deviation.

Table 2.
The cause and treatment of 35 eyes of patients with filamentary keratitis patients examined
Ocular disease Number of eyes Treatment Total number of filaments before Tx Total number of filaments after Tx (RP)
KCS only 11 (31.4%) AT + AB + T 56 5 (91.1%)
Corneal occlusion 24 (68.6%)   89 0 (100%)
  Paralytic strabismus 10 (28.6%) B (extra ocular muscle) + AT + AB + T 38 0 (100%)
  Primary blepharospasm 10 (28.6%) B (eyelid) + AT + AB + T 38 0 (100%)
  Ptosis 4 (11.4%) BP + AT + AB + T 13 0 (100%)

KCS = keratoconjunctivitis sicca; AT = artificial tear; T = T-lens insertion; B = botox injection; AB = antibiotic eyedrops (levofloxacin 0.5%); BP = blepharoplasty; RP = recovery probability.

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