Current Health Issues in the Caribbean

BLINDNESS IN THE CARIBBEAN

Alfred L. Anduze, M.D. St. Croix Vision Center St. Croix Hospital St. Croix U.S. Virgin Islands

Caribbean Studies Association Merida, Mexico May 26, 1994 Abstract:

Blindness in the Caribbean

Background: The prevailing of blindness in the Caribbean region are reviewed in the context of world blindness statistics to identify differences and similarities that might exist.

Method: A review of the status of blindness in the U.S. Virgin Islands, Barbados, Jamaica, Puerto Rico, Trinidad, and Mexico; individually with regard to causal etiology, epidemiology, treatment and possible future research.

Results: Blindness in the Caribbean is the result of genetics, tropical environment and cultural habits of the inhabitants and consist of Age-related macular disease, Infectious diseases, Diabetes mellitus, , Congenital defects, Xerophthalmia, , Trauma and .

Conclusion: There are almost 50 million people who are legally blind worldwide (i.e. with a vision of 20/200 or less) 2-3 million in the Caribbean region. The social and economic consequences are serious additional deterrents in developing countries. Outline:

Causes of Blindness in the Caribbean

I. Age-related macular disease

a. Vascular insufficiency b. Senile

II. Cataracts

III. Glaucoma

IV. Diabetes mellitus

V. Infectious diseases

a. Trachoma b. c. Leprosy d. Toxoplasmosis e. Toxocariasis f. AIDS

VI. Trauma

a. industrial/work-related b. sports c. home accidents

VII. Nutritional

a. Xerophthalmia/ b. Iron-deficiency anemia c. Tobacco/Alcohol

VIII. Congenital defects

a. genetic syndromes b. Legal blindness is acceptably defined as vision 20/200 (6/60) or less. An individual with this level of vision has difficulty carrying out normal activities of daily living (ADL) without some kind of low vision aid or appliance. In developing countries this often involves dependency on another individual thereby reducing or removing two people from the ranks of productivity. The reduced quality of life, social stigmatization, and psychological withdrawal that accompanies most individuals with subnormal vision can often lead to reduced life expectancy. In the Caribbean region, there is hardly a single family without at least one member who is or has been afflicted with blindness.

A review of the principal causes of blindness in the Caribbean islands of Barbados, Jamaica, Puerto Rico, Trinidad, the U.S. Virgin Islands (1), and the nation of Mexico (2), reveals that

1. 2. Glaucoma 3. Diabetes mellitus 4. Age-related macula* disease 5. Trauma 6. Infections/diseases 7. Nutritional Deficiencies 8. Congenital Defects

are the most prevalent.

These are presented in outline form for purposes of clarity: Underlying etiologies include genetic make-up, environment and cultural habits.

In decreasing order of frequency:

VIII. CONGENITAL DEFECTS such as Down's Syndrome, Tay-Sach's disease, Stargardt's disease, and pigmentation are generally less in the developed countries, since the gene pool is more hybridized and varied. Strabismus leading to is slightly less than the 2.5% quoted worldwide. (2) The incidence of incapacitating blindness has been reduced somewhat due to surgical innovations and medical implementation in the more developed countries, but remains a significant detriment in the poorer areas. NUTRITIONAL DEFICIENCIES in reference to blindness specifically targets as the most prevalent cause. There are various factors that impair Vitamin A status: hot dry seasons lead to a short supply of source food; peak age is 3-6 years old, males are at greater risk than females; precipitating illnesses include gastroenteritis and respiratory tract infections. The pattern of disease includes night blindness, Bitot's spot and conjunctival xerosis (drying), hence the inclusive term "xerophthalmia". Treatment involves the consumption of foods containing Vitamin A and carotene, and/or massive amounts of vitamin A (100,000 IU/daily). It can be noted that 100 grams of mango provide all the daily needs of vitamin A as well as all the fructose needed to precipitate diabetes mellitus. Many areas of Mexico and Central America have a high incidence of . Iron deficiency anemia is quite common in the Caribbean islands among pre-teens and teenagers due to inappropriate diet, as well as in areas where the diet is high in starch and low in protein. The well-known term "blind drunk" is not a misnomer as the effect has come to be known as tobacco/alcohol retinopathy. This, coupled with the fact that many inhabitants fail to eat a balanced diet, can lead to extensive nerve degeneration in the .

VI. TRAUMA to the eyes with loss of vision is increasing in frequency along with industrial development and social sophistication. Cataract, and irreparable scars are the main results of chemical injuries, pressure injuries (explosions), and misapplied mechanical implements. Sports and recreation injuries are also increasing despite better equipment and higher awareness. Accidents in and around the home coincide with "modern" implements such as barbed wire and handguns.

V. INFECTIOUS DISEASES as a major cause of blindness have been on the decline until recently with the advent of increased bacterial and parasitical resistance to antibiotics.

Trachoma has long held first place as a cause of blindness in hot, dry areas. Most of the cases in the Caribbean, however, are from elsewhere (South America, Northern Africa and the Middle East). Caused by Chlamydia trachomatis, it consists of acute developing into extensive lid and corneal scarring. Treatment is with the timely topical and systemic application of antibiotics (sulfacetamide, tetracycline, erythromycin). Onchocerciasis (African River Blindness) is caused by the worm, onchocerca volvulus, found in rural areas with rapidly running streams, flies and crabs, mainly central America and Mexico. Blindness occurring as the result of , optic atrophy and , destruction of the layers of the eye, is usually bilateral and total. Treatment is difficult and consists of surgical removal of nodules containing the worm and antihelminthic medications with variable effect.

Toxocariasis is the infection in man with the eggs of the roundworm, Toxocara canis, via ingestion (pica), through the alimentary system to the blood circulation and hence to the eye. It is usually unilateral and causes complete blindness. It is still prevalent on all Caribbean islands where dogs and cats abound.

Filariasis is the infection of the body by the roundworm (loa loa) which is ingested and matures in the tissues of the eye thus leading to retinal and choroidal damage. This is the same nematode responsible for Elephantiasis, (gross edematous swelling of the lower extremities-"big foot", which on the more developed islands, is on the decline.

Leprosy, resulting from infection by mycobacterium leprae, is still present throughout the Caribbean and is especially high in Mexico and Central America. A hot, dry climate, inadequate health care, and low socioeconomics contribute to maintaining its prevalence. Early detection and Dapsone tablets are the treatment of choice.

Toxoplasmosis is caused by the protozoan T-Gondii, which affects both eyes and is characterized by recurrences and remissions and can be transmitted from mother to fetus. There is extensive chorioretinal scarring and generalized resistance to treatment, with blindness occurring early. There can be extensive brain damage from calcification.

The blindness resulting from Auto Immune Deficiency Syndrome (AIDS) can be rapid and total - is often accompanied by concomitant infections such as the Toxoplasmosis and Cytomegalo virus, which are highly resistant to treatment. Of the common causes of blindness on the mainland U.S.A., senile macular degeneration has long been the chief concern. Known more recently as ARMD (age-related macular disease) it occurs predominantly in aging individuals of Caucasian lineage. As non-Caucasians ascend on the socio- economic scheme and extend their life expectancy, the incidence of ARMD also rises. Cataracts appear to be more prevalent in the Caribbean but actually occur with equal frequency when compared to other regions- though they appear at an earlier age, it takes longer to become incapaciting. (4) Glaucoma is eight (8) times more prevalent in non- whites than in whites and four (4) times more likely to lead to blindness. Diabetes mellitus has an incidence of 11.1% in the USA and 30% in the ophthalmic population over the age of 40 in the U.S. Virgin Islands. A diet high in starches and sugars, the cultural habit of festive overeating, and basic genetics all play decisive roles in leading to this exceptionally high rate.

As the population ages, the incidences of all four conditions increase and appear in combination. Fifty (50%) of the diabetics in the Virgin Islands have glaucoma, 66% will develop debilitating cataracts by the age of 70, and all will have developed ARMD by the age of 80.

DIABETES MELLITUS (inability to metabolize sugar correctly in the body tissues) affects females twice as much as males. It affects non-whites twice as often as whites; 5% of all West Indian diabetics are blind, and 80% of these die within 5 years of the onset of blindness. The typical diabetic patient tends to be obese, has glaucoma, significant cataracts, hypertension, hypercholesterolemia and cardiovascular insufficiency. Blindness occurs through a combination of events. Intractable glaucoma (high intraocular pressure and low vascular pressure) leads to atrophy. Dense cataracts which undergo surgical removal with delayed and complicated healing contribute to the blinding process. Recurrent venous hemorrhage in the retina and vitreous whose repair process of scarring leads to proliferative (new weaker blood vessels) retinopathy. The mainstay of treatment is early and maintained diet control, along with oral hypoglycemics and insulin products. Several West Indian traditional treatments include aloe vera, "caca poule" and "bois canon" teas, and mormordica charantia or "maiden apple" tea. These are effective when used for mild conditions and must be accompanied by the proper diet and monitoring. Technology has yielded Argon and Krypton Laser treatment which temporarily delays the progression of proliferative retinopathy, and must be administered at or near the critical Stage III of the disease. Failure to achieve early treatment renders the process ineffective. Vitrectomy surgery for stages IV and V rarely yield a visual acuity of better than 20/200.

GLAUCOMA is so prevalent throughout the West Indies that competing research projects are being conducted on St. Lucia and Barbados just to study the aspects in a seemingly vain attempt to slow the resulting blindness. There is a strong genetic component and the age of onset is around forty (40) years and increases linearly with advancing age. It is characterized by a failure of the trabecular meshwork (inside the eye) to filter and allow agueous fluid to leave the eye. The pressure increases and leads to severe optic nerve damage (cupping), loss of peripheral visual field and eventually central field. The normal intraocular pressure range is 10- 20 mm Hq. Above 22 mm Hq., optic nerve fibers begin to degenerate. Optic nerve fibers in some people can bear more pressure that in others. Hence, the interplay of other factors, nutrition, vascular status, genetics, environmental stresses, and cultural habits become more significant. Treatment of glaucoma with conventional medicines, Yag and Argin Laser and surgical filtration procedures are not curative but may offer temporary relief. As with the previous causes of blindness, prevention and early detection are the keys.

CATARACT formation in tropical regions occurs at an earlier age than in other regions. The presence of a high incidence of nuclear/brunescent changes correlates well with the presence of Ultraviolet B and Ultraviolet A radiation from the sun. However, there is no greater incidence in males engaging in outdoor activities that in females who had significantly less exposure. The positive correlation is with diabetes (50.5%), hypertension (43%), glaucoma (9.5%) patients on two or more systemic medications (81%) and with increasing age. West Indian cataracts tend to be dense, highly pigmented and difficult to separate from the capsule due to cumulative posterior radiation fusion. Those with decreasing vision tend to wait until they see almost nothing at all (40% with vision of finger counting, hand motion or light perception) before they seek treatment. Cataract surgery has advanced rapidly in the past ten years and though introcular implantation is now the rule, patients with diabetes, glaucoma and macular degeneration often continue to lose vision. AGE-RELATED MACULAR DEGENERATION is the most complex and most untreatable of the causes of blindness. Every human being over the age of 80 will show significant retinal degenerative changes. As the leading cause of blindness in developed countries, it is becoming more prevalent in the developing countries. In the Caribbean, as the environmental stresses, dietary habits and cultural mores are changing, so the incidence of neuro-vascular incidents and disease appears to be increasing. Many cases of ARMD also have glaucoma, cataract or diabetes, so it is difficult to study it in isolation. Degeneration of nerve tissue due to ischemia (oxygen deprivation) is appearing at an earlier age and is more debilitating in this population now than at a time when the diet and activities were different.

The factors common to these main four causes of blindness include advancing age, reduced activity, ensuing vascular insufficiency, and neural degeneration. Though there is no known remedy for aging, its effects can be softened by early moderation of lifestyle habits, a sensible balanced diet and early detection of treatable defects. Bibliography:

1. OSWI - Ophthalmological Society of the West Indies. Statistics have not been adequately compiled there are generalized and derived from estimates given by representatives of the included islands: Puerto Rico, U.S. Virgin Islands, Barbados, Jamaica and Trinidad.

2. Vital World Statistics: Time Books, Random House 1990, Section on Health. 3. Field Guide to the detection and control of xerophthalmia. A. Sommer, WHO 1982 4. Ultraviolet Radiation and Cataract Development in the U.S. Virgin Islands. Refractive Cataract Surgery; Vol. 19, March 1993. Alfred L. Anduze, M.D.