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Year : 1988  |  Volume : 36  |  Issue : 1  |  Page : 27-28

Conjunctival mucus ferning in hypovitaminosis A

Department of Ophthalmology, St John's Medical College Hospital, Sarjapur Road Bangalore-34, India

Correspondence Address:
D P Edward
Department of Ophthalmology, St John's Medical College Hospital, Sarjapur Road Bangalore-34
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Source of Support: None, Conflict of Interest: None

PMID: 3253194

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The ocular ferning test was used to qualitatively assess mucus function in early stages of xerophthalmia. The results indicate that inspite of histological evidence of loss of goblet cells in the early stages, mucous function and production is sufficient to produce ferning. It is suggested that such derangements in mucous ferning may occur in more advanced stages of xerophthalmia.

How to cite this article:
Edward D P, Mascarenhas F K. Conjunctival mucus ferning in hypovitaminosis A. Indian J Ophthalmol 1988;36:27-8

How to cite this URL:
Edward D P, Mascarenhas F K. Conjunctival mucus ferning in hypovitaminosis A. Indian J Ophthalmol [serial online] 1988 [cited 2021 Jun 14];36:27-8. Available from: https://www.ijo.in/text.asp?1988/36/1/27/26170

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  Introduction Top

The importance of mucin in the pre- ocular tear film is to decrease the surface tension of tears and increase the wetting of the corneal surface. Methods of studying mucous production include histological methods like conjunctival biopsy and impression cytology; qualit­ative methods used are tear break up time, .the Rose Bengal die test and ocular ferning. The ferning test is based on the unique ability of mucin to "fern" which is a physical characteristic by which mucin crystallizes in the presence of sodium chloride. This phenomena which can be observed on a dry slide preparation under a microscope was utilized by Khalid et al to qualitatively evaluate mucin deficiency in Pemphigoid and Steven Johnson's syndrome [1]. Using histological methods, the early stages of hypovitaminosis A are characterized by marked loss of goblet cells[2],[3]. However, clinically these stages are marked by patchy conjunctival xerosis and Bitot spots. Punctate keratopathy, which is the only observation indicative of tear film dysfunction has been noted in a large number of patients in stage XN of xerophthalmia [6] but its aetiology has not been attributed to goblet cell loss [7]. In view of these earlier observations, this study was undertaken to qualitatively assess mucin production in the early stages of xerophthalmia using the ocular ferning test.

  Materials and Methods Top

1314 children were examined in three schools of Kollegeal Taluk, Karnataka during an eye camp for signs of Vitamin A deficiency. The affected children were grouped using the WHO classification for xeroph­thalmia.

Conjunctival smears were taken from the lower bulbar conjunctiva using the method described by Khalid et al [1], and these smears examined under a light microscope for the presence of ferning. In addition, two groups of controls were evzaluated in the study. The first being a group of 40 healthy children who were age matched and selected randomly from the same schools. The second group consisted of 15 patients with external inflamma­tory ocular disease which included bacterial, viral and allergic conjunctivitis from the eye outpatient depart­ment at the St John's Medical College Hospital, Banga­lore. Dry conjunctival smears from both these groups were examined for the presence of ferning.

  Results Top

Of the 1314 children examined in the three schools, 45 children showed signs of xerophthalmia, stage XI A and XI B. The age of these children ranged between 5 and 14 years. In the group of 45 affected children, 30 belonged to stage XI A and the remaining 15 to stage XI B. Children with symptoms of stage XN were excluded from this study. [Table - 1] depicts the feming pattern in the groups exhibiting signs of stage XI A, XI B and the controls. 28 smears showed positive feming [Figure 1] in the XI A group (93.3%) and 13 in group XI B (86.6%). The control group consisting of healthy children (Group 1) exhibited ferning in 39 smears (97.5%) whereas the controls from the group with conjunctival inflamma­tion (Group 2) showed feming in 13 cases (86.6%). There was no statistical difference in the occurence of ferning in groups XI A and Xl B when. compared to the two control groups (p > 0.5).

  Discussion Top

It has been observed that Hypovitaminosis A results in a mucin deficient state by virtue of a change of the mucous epithelium to a keratinized epithelium and the disappearance of conjunctival goblet cells'. Also, the phenomena of feming may be absent when either sodium chloride or mucus are deficient in the tear film.

The findings in our study indicate that in stage X1 A and XI B of xerophthalmia, there was no significant diffe­rence in ferning when compared with normal controls. Also, ferning in both stages were comparable to that seen in patients with inflammatory disease of the conjunctiva These results differ from a previous study where ferning was absent in significant number of cases in cicatrizing conjunctivitis [2]. This suggests that in stage X1 A and Stage XI B the quality of mucus produced is unaffected or the production of mucus is so minimally disturbed that smears still exhibit ferning.

In contrast using histopathological techniques [4] and more recently, impression cytological of the conjunctival mucus [5],[6] investigators have demonstrated that in the early stages of xerophthalmia there is significant loss of goblet cells, enlargement, separation, and keratinization of the epithelium Such histopathological studies how­ever, give information about the disease process only in representative areas where the biopsy is performed. Therefore it appears, that inspite of cytological loss seen in stages XI A and X1 B, the remaining goblet cells are sufficient to produce normal ferning. Bitot spots in Hypovitaminosis A are known to persist after treat­ment [2],[3],[4],[5]. The question of the 13 cases in the group XI B being those which are unresponsive treated cases was also taken into consideration. To our knowledge none of the children included in the affected group, had received any supplemental Vitamin A therapy during the past year. Furthermore it is unlikely that such a large percentage of children (86.6%) would be from this category, the reported incidence being relatively low [2].

In conclusion, the observations in this study suggest that qualitative assessment of ocular mucus using the ocular ferning test gives a more total picture of the interactions between the mucus and the aqueous layers in the preocular tear film which are indirectly indicative of tear film stability. On the other hand, methods like impression cytology help in early detection of the disease but do not give us information about the functional status of the tear film It is likely that in the more advanced stages of corneal xerosis and ulceration where the loss of goblet cells is much greater, loss of ferning pattern would be seen.

  References Top

Khalid FT, Okumoto M : Ocular ferning test Ophthalmology 89 : 712-4, 1982  Back to cited text no. 1
Sommer A, Green R Kenyon KR : Bitot spots responsive and unresponsive to Vit A: Clinicopathological correlation. Arch. Oph­thalmol 99 : 2014-27, 1981.  Back to cited text no. 2
Wittpen JR Scheffer CG, Tseng CG, Sommer A : Detection of early xerophthalmia by impression cytology. Arch Ophthalmol 104: 237­239, 1986.  Back to cited text no. 3
Tseng S : Staging of Conjunctival squamous metaplasia by impres­sion cytology. Ophthalmology 92 : 728-73 3, 1985.  Back to cited text no. 4
Sullivan WP, Mc Culley, JP, Dohlman CH: Return of goblet cells after Vitamin A therapy in xerosis of the conjunctiva Am. J. Ophthalmol 75 :720-725, 1973.  Back to cited text no. 5
Sommer A. Emran N, et al: Vitamin A responsive punctate keratopathy in xerophthalmia. Am.J. Ophthalmol 87: 330-333, 1979.  Back to cited text no. 6
Dohlman CH, Kalevar V : Cornea in Hypovitaminosis A and protein deficiency. Isr. J. Med. Sci. 8 : 1179, 1972.  Back to cited text no. 7


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