|Year : 1991 | Volume
| Issue : 3 | Page : 105-107
Modified classification of xerophthalmia
State Institute of Ophthalmology, M.D. Eye Hospital, Allahabad, India
State Institute of Ophthalmology, M.D. Eye Hospital, Allahabad
Source of Support: None, Conflict of Interest: None
"There are many classifications of xerophthalmia in existence. In the present study all these classification have been exhaustively reviewed. Many objections to previous classifications have been raised following experiences with these classifications for over six years. Based on these objections a self explanatory, easy to remember and modified classification has been proposed, which will be of use in wider areas."
|How to cite this article:|
Singh K. Modified classification of xerophthalmia. Indian J Ophthalmol 1991;39:105-7
| Introduction|| |
Xerophthalmia is a world wide problem. For many years there has been a need for a classification of xerophthalmia to permit a clearer reporting of the various eye changes, generally agreed to be characteristic of the condition. A classification of Xerophthalmia was proposed at the JOINT WHO/USAID meeting  in 1947 to help the surveyors and clinicians. This classification was modified at the Joint WHO/ USAID/UNICEF/Hellen Keller International IVACG Meeting  in 1980. After working for over six years with these classifications, there was some confusion, objections were raised and queries made by some colleagues. This led me to think over the problem and modify the classification to make it more explanatory. The modified classification is given below.
The first classification to gain some degree of general acceptance was the one proposed by Ten Doesschate in 1968, which was based on a scheme commonly used in Indonesia.
He classified xerophthalmia in the following way:
X0 : Night blindness only
X1 : Xerosis of conjunctiva, with or without night blindness and with or without Bitot's spots.
X2 Xerosis of cornea; superficial, reversible changes of the corneal epithelium.
X3 : Irreversible corneal changes, involving the corneal stroma; leading to loss of substance and perforation, and possibly keratomalacia (colliquative necrosis).
X4 : Scars presenting as nebulae, a total or partial leucoma a staphyloma, or phthisis bulbi.
This classification was subsequently expanded to include night blindness and corneal sequellae by the Joint WHO/USAID meeting  held at Jakarta in 1974. It is a further modification of the earlier proposals.
Classification of Xerophthalmia Primary signs
X 1 A: Conjunctival xerosis
X 1 B : Bitot's spots with conjunctival xerosis X2 : Corneal xerosis XiA : Corneal ulceration with xerosis X3B : Keratomalacia
XN : Night blindness
XF : Xerophthalmia fundus XS : Corneal scars
Explanatory notes on the classification:
1. These signs are descriptive rather than diagnostic; all signs seen at the time of examination are
2. In general, a progression of severity is reflected in the classification of primary signs.
3. The classification can be used in both field surveys and the routine recording of findings in patients in hospital and clinics.
4. When tabulating the frequency of these signs each child should be included only once, under his or her most severe sign.
5 Only those Bitot's spots accompanied by conjunctival xerosis, usually in the 0-5 years age group, are indicative of vitamin A deficiency. This xerosis may be hidden by the overlying foam of the Bitot's spot and revealed only when this is rubbed away.
6. Secondary signs often occur in association with or result from vitamin A deficiency and should be noted separately.
The classification, mentioned above has been modified . at the joint WHO/USAID/UNICEF/Hellen Keller International/IVACG Meeting  held at Jakarta in 1980. The previous division into primary and secondary signs was considered unnecessary and was abolished. The division of X3 into X3A and X3B was modified to relate more closely to the degree of damage and the ultimate prognosis for vision. Following is this classification of xerophthalmia.
XN : Night blindness
XN : Conjunctival xerosis XIB : Bitot's spots
X2 : Corneal xerosis
X3A Corneal ulceration/keratomalacia less than 1/3 corneal surface.
X3B : Corneal ulceration/keratomalacia equal to or more than 1/3 corneal surface.
XS : Corneal scar
XF : Xerophthalmia fundus
Objections to the previous classifications
Though, there are not too many lacunae in the previous classifications, the following points force us to think over another classification.
A clinician, who uses this classification regularly e.g. in surveys, can immediately reach the class after examining the patient, but for a fresher it is difficult to remember. So while the classification can be used in field surveys, it has not been used routinely in clinics. Furthermore, in conferences, if the audience is not aware of the classification before hand, they get confused with the terms XIA, XIB, X2, X3A, X3B. At the same time anybody can easily catch the word XN, XF, XF or XS because these 'N', 'F' and 'S' clearly signify night blindness, xerophthalmia fundus and corneal scars respectively.
The classification has been depicted by both letters and digits. Therefore, the uniformity of the classification is not maintained. Though, the digits reflect the progression of severity of the disease, it is not very much required, since any surveyor or ophthalmologist knows. To reach the stage of keratomalacia the conjunctival xerosis, Bitot's spot and corneal xerosis must be gone through.
The division of the stage of X3 into X3A and X3B relates closely to the degree of damage and ultimate prognosis of vision. This is not required because the X3A stage gives a lesser jolt to the mind as to the alarming situation before the physician. Whereas, the fact is that keratomalacia, whether of a small or large part, if left untreated, will definitely lead to the involvement of the whole of the cornea and ultimately to blindness. Therefore, equal importance should be given to X3A and X3B.
The corneal scar designation by 'XS' is self explanatory but is would be better if XS is divided into two classes . The involvement of the central part of cornea means that the pupillary area is covered by corneal scar and the patient is blind . The involvement of the peripheral part means that the vision is not hampered by the corneal scar. This will be helpful in surveys because these classes will clearly show the percentage of population becoming blind due to xerophthalmia. Thus, an erroneous exaggeration of statistics due to XS alone could be avoided.
Keeping these points in mind, the following modified classification is proposed
Xn : Night blindness
XCj : Conjunctival xerosis
XB : Bitot's spots
XCo : Corneal xerosis
XU/K: Corneal ulceration and/or keratomalacia in any part of cornea.
XSc : Corneal scar - central part
XSp : Corneal scar - peripheral part
XF : Xerophthalmia fundus
XCj : 'C' for conjunctival and 'X' for xerosis are self explanatory in place of X 1 A.
XB : In the X 1 B the digit '1' id deleted, because Bitot's spot in any child below 6 years of age means that the stage of XiA or XCj has already occurred.
XCo : 'C' for corneal and 'X' for xerosis are self explanatory in lieu of X 2.
XU/K: 'U' for ulceration and 'K' for keratomalacia are self explanatory; the division of this stage into two has been deleted to give due importance to the involvement of any portion of the cornea in this class.
XSc 'XS' is corneal scar and 'c' for center are self explanatory.
XSp : 'XS' for corneal scar and 'p' for peripheral part are self explanatory.
Rest of the classes of XN, and XF of the previous classifications, are self explanatory and need no change.
Various classfications of xerophthalmia have been reviewed. There are a few objections and confusions in the previous classfications . It is difficult to remember . It has been used sparingly in clinics. The XN, XF, XS are self explanatory but X 1 A, X 1 B, X 2 , X 3 A, X 3 Bare not that clear 4sub . Proq y ression of severity in classifications is not required. The division of X3 into X3A and X3B conveys lesser importance to X3A in the mind of the physician for the therapy.
Based on these objections, a modified classification has been proposed as follows :
XN : Night blindness
XCj : Conjunctival xerosis XB : Bitot's spot XCo : Corneal xerosis
XU/K: Corneal ulceration and/or keratomalacia of any part.
XSc Corneal scar in central part XSp : Corneal scar in peripheral part XF : Xerophthalmia fundus
The author is grateful to Prof. D. Srivastava, Prof. R.N. Misra and Dr. R.R Singh, who have been helpful in providing all kind of guidance, whenever needed. The author is also thankful to Mr. Shrish Kumar Srivastava for typing this manuscript.
| References|| |
WHO Technical Report Series No. 590, 1976 (Vitamin A Deficiency and Xerophthalmia : Report of a Joint WHO/USAID meeting) P 17-18.
WHO Technical Report Series No. 672. 1982 (Control of Vitamin A Deficiency and Xerophthalmia Report of a Joint WHO/UNICEF/USAID/Hellen Keller International/IVACG Meeting) P 13.
DOESSCHATE, J. TEN. Causes of blindness in and around Surabaja, East Jawa, Indonesia. Thesis, University of Jakarta (1968).