Historical Cataract Definitions
A few of the terms used to indicate varieties of cataract are quite fanciful, while still others indicate conditions that have nothing whatever, either, directly or indirectly, to do with a loss of transparency in the lens or its capsule. Even the word cataract itself (derived from, the Greek kata, down, and arassein, to fall) has a misleading etymology, based upon an ancient and mistaken pathology. The Greek kataraktes is probably a translation of the still older Arabic word for a spot in the pupil, which meant a "waterfall," i.e., "water entering the eye." This meaning of the word is further shown by a medieval synonym for cataract, aqua descendents in oculo. Obviously incorrect and misleading, also, are such terms as fibroid cataract (opacity, not in the lens), green cataract (a medieval term for glaucoma), grumous cataract, albuminose cataract, dry cataract (cataract arida), hyaloid cataract, choridal cataract, hemorrhagic cataract, and other examples that will occur to the reader. Because of their obsolete character and for other reasons a considerable proportion of cataract nomenclature has ceased to be employed in the literature of modern ophthalmology. On the other hand, the student of medical history and of early ophthalmic literature will find the minor headings following this rubric of some assistance in his researches.
Classification. As proposed by Dor, all cataracts may be divided into three general divisions, i.e., congenital, traumatic and acquired. Beard (Ophthalmic Diagnosis, p. 150) .gives a most useful classification, as to age, cause, etc. It is as follows:
- According to the age at which it appears: Congenital, juvenile, adult, senile.
- According to the cause: Spontaneous, traumatic, symptomatic, albuminuric, arterio-sclerotic, chemic, thermic, heat, cold, electric, diabetic, glaucomatous, malarial, phosphaturic, naphthalinic, spasmodic, ergotinic, ciliary cramp, tetanic, thryoidismic, uveitic.
- According to consistency: I.1iquid, soft, 'semi-hard, hard, ossific, calcific.
- A.ccording to color: White, gray, greenish, amber, black, blue.
- According to extent: Total, partial, nuclear, perinuclear, cortical, capsular.
- According to the seat and disposition of the opacities; Central, nuclear, perinuclear, anterior cortical, pooterior cortical, anterior polar, posterior polar, equatorial, disseminated; punctate, zonular.
- According to the presence or absence of complications: Simple, complicated.
- According to the period of development: Incipient or commencing, immature, mature, hyper-mature or regressive.
Etiology. Although cataract is generally considered to be (as it is in the majority of instances) a senile degeneration, yet almost all pathologic states that effect the nutrition of the eyeball may produce it. In that sense it is generally a. secondary disease, and we know that nephritic alterations, diabetes, exposure to great heat, various poisons, arteriosclerosis, ergotism, auto-intoxication, eye-strain, injury to the lens or surrounding parts, heredity, etc., are regarded as exciting causes of it.
Symptoms. There are no constant symptoms of cataract in general especially in the early stages. Sight will not be much affected until the nucleus (in the area of the pupil) is involved.