|Year : 1979 | Volume
| Issue : 4 | Page : 180-184
Daljit Singh, Mohindar Singh, Shiv Inder Singh Rudra
Medical College, Amritsar, India
Professor of Ophthalmology, Medical College, Amritsar
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Singh D, Singh M, Rudra SS. Climatic keratopathy. Indian J Ophthalmol 1979;27:180-4
This disease is characterized by the presence of amber-coloured deposits in the Bowman's zone of the interpalpebral area of the cornea. The disease varies in severity from localized mistiness of the cornea to the development of large nodules and severe opacification.
Bietti made a detailed study of this condition in Saudi Arabia. Similar cases were further reported from Libya (Gundolfi) Transwaal (Etzine and Kaufmann), Somalia (Fertillere et al) and Dahlak Islands. (Rodger) etc. A less severe form of the disease was reported as Labrador keratopathy from Canada (Freedman) and Nama keratopathy from South Africa (Freedman). (Fraunfelder and Hanna) gave a general name of Spheroidal degeneration to all the related lesions described by the earlier authors under various names.
During the last three years we have come across similar lesions amongst our patients. This report which happens to be the first from India documents our observations in a total of 81 patients.
| Observations|| |
Stages of the disease
Depending upon the site of involvement and the severity of the lesions, the disease was divided into 4 grades.
Extremely tiny microscopic "oil droplet" like deposits are visible in the epithelium. They are situated mostly in the nasal or temporal periphery of the cornea near the limbus. Occasionally they may be present only in the central part of cornea, or stimultaneous with the peripheral involvement. The vision is unaffected. The lesions of this stage are visible only by slit lamp microscope. They are best seen by retroillumination.
There is seen a fine granularity in the interpalpebral area of the cornea giving it a slightly groundglass appearance. This change is confined to the Bowman's zone. The vision at this stage is only slightly affected. This stage is visible with a corneal loupe. Somewhat severer forms are visible even to the naked eye.
In this stage amber coloured spherical nodules become visible to the naked eye. They are raised above the surface of the cornea. They may occupy the peripheral or entire interpalpebral zone. Their number and sizes are variable. Usually they remain discrete but can become confluent. When present in the central part, the vision is markedly diminished.
here is thinning and opacification of the superficial corneal stroma in the region of the original involvement. At this stage gross visual deterioration is evident. Such patients are liable to develop indolent corneal ulcers.
All these grades may be found in various combinations in the same individual. These degenerative lesions do not lead to vascularization of the corneal tissues. There is a decrease in the corneal sensitivity over the diseased area.
[Table - 1] shows the age and sex distribution in the eyes affected.
This keratopathy was found to be more common in the males (79%). The majority of the cases (92.6%) were above 60 years of age. Although the majority of the cases (86.4%) showed bilateral involvement, but some cases (13.6%) had unilateral lesions.
[Table - 2] shows the various grades of the disease:
Cases showing similar lesions secondary to some recognizable corneal disease were not included in this series. It will be seen that in this series most of the cases belong to the grade 3. This is because in the early part of our study the cases were selected by naked eye examination. It is only recently that attention directed towards the early lesions. Thus the percentages given here are not true representative of the incidence of the disease.
The lesions were mostly seen in the farmers engaged in agricultural work for years together (say 20 to 40 years). They had laboured for most of the time without any protection to the eye from sunlight, dust and wind. Patients were generally well fed and did not show any signs of dietary deficiency.
Histopathology was done in keratectomy specimens obtained from advanced cases only. The study was made by Dr. Greer of Australia. Haematoxilin, Eosin and Ayoub Shklar stains were used.
The epithelium showed vacuolation of many cells with associated desquamatization and thinning. A very large number of epithelial cells showed the presence of an amorphous material of varying density. Tne change appeared to involve mainly the area of the nucleus. Multiple globular deposits of varying sizes were also seen in the deeper layers of the epithelium. The Bowman's membrane while not visible at some places appeared to be thickened at many places. The superficial corneal stroma was found impregnated with numerous amorphous deposits of varying sizes and density, The deposits assumed varying shapes-round, oval, irregular and linear, single or in small to large groups. [Figure - 3],[Figure - 4],[Figure - 5].
Ayoub Shklar stain for keratin was positive for the deposits described above.
| Discussion|| |
Generally, every author has reported this disease under a separate name and has no uniformity in its terminology is yet established. The suggested names are based upon the presumed aetiology Freedman, Klintworth, the clinical appearances Falcone Bietti et al, Gundolfi Fraunfelder and Hanna and Anderson and Fuglsang, the chemical nature of the deposits Garners Christensen Brownstein and Fine the geographical area Freedman Wyatt and the population investigated Freedman
Most of the studies,,,, claim that climatic exposure is the most important causative factor. Therefore we for the time being prefer to call this condition as climatic keratopathy.
Fraunfelder and Hanna divided this condition into three forms: Corneal primary, corneal secondary and conjunctival. We have not encountered any case of conjunctival form so far and we have excluded cases with secondary corneal form which is commonly seen in case of corneal scarring, oedema and pterygium. Most of the cases (59.3%) in our series showed advanced lesions (Grade 3). This is because in the early part of our study the cases were selected by naked eye examination.
Microscopic findings similar to those described in this paper have been described by others,.
The chemical composition of the deposits is still not exactly known. Reports have stated this material to be hyaline, colloid, a protein high in tyrosine, lipids, elastin and even an incomplete form of keratin. Ayoub Shklar stain for keratin has been positive in our cases.
The electron microscopic study by Hanna and Fraunfelder indicated that the spheroids develop from extracellular material deposited on the collagen fibrils. This extracellular material appeared to be secreated by abnormal fibrocytic cells of the cornea. The material is condensed to form small spheroids. These may increase in size or accumulate to form large groups. On the other hand according to Garner et al the evidence points towards an epithelial origin for the keratin like material. Whether it is a product of active secretion or as would seem more likely of cell degeneration and lysis can not be stated.
Histology in our cases shows that at many places the keratin like stromal deposits have no physical contact with the epithelium and even an intact Bowman's membrane may be present at such sites. At other places we find deposits of keratin like material occuring within the epithelial cells and having no physical contact with the stroma. Therefore it seems to us that the origin of the deposits may be dual, i.e. from the epithelium, stroma or both. Further work will have to be done to elucidate its pathogenisis.
This disease has been found to occur especially in those who spend much of their lives out of doors. Exposure to sun light has been suggested to be of pathogenic importance Fraunfelder and Hanna, Freedman, and Anderson and Fuglsang. Other specific factors that have been suggested as contributory include aging and low humidity causing dryness of the cornea, microtrauma by wind mixed with sand or ice and extremes of high or low temperature Malnutrition and genetic factors were also incriminated.
At this stage of the study it is difficult to suggest any definite preventive measure apart from the use of sunshades and sunglasses. In advanced cases larnellar keratoplasty will be certainly helpful.
| References|| |
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[Figure - 1], [Figure - 2], [Figure - 3], [Figure - 4], [Figure - 5]
[Table - 1], [Table - 2]