TRAUMATIC CATARACT.-AS a rule, this form of lenticular opacity is the re sult of a rupture or disturbance of the capsule of the lens from an injury which permits the aqueous or vitreous humor to come into contact with the lens-fibres. The laceration in the capsule may be caused hy eitber direct injury by means of the penetration of a foreign body or indirectly by contusion.
Shortly after the capsular laceration the lens-fibres near the rent begin to cloud and swell. Later, if it be the ante rior capsule that is injured, they ooze out into the anterior chamber, appearing as gray, fluffy-looking masses. The aque ous humor, however, soon dissolves the lens-masses that have passed into the anterior chamber, and, gaining freer access to the interior of the lens by the removal of the primary plugs of lens matter, causes more or less of the lens substance to become opaque, swelled, and absorbed. In this way, after the lapse of some time, the major portion of the lens-substance may be dissolved and the pupil again become almost black. In most cases, however, the capsular wound cicatrizes and becomes closed, stopping the process of absorption before the removal of the lens-material by the spontaneous-liquefying method is fully attained.
Many cases of traumatic cataract pur sue their course with but few signs of inflammation, but a successful termina tion is often prevented by tbe develop ment of iritis caused either by direct in jury or by pressure of loose or swelled lens-matter. Septic matter may be also introduced into the eye either at the time of the tiaumatism or later, giving rise to iridocyclitis, panophthalmitis, and even periophthalmitis. If not pre vented it not infrepently happens that secondary glaucoma supervenes. This condition is generally due to either a blocking of the angle of the anterior .ehamber by pressure or the presence of a mass of lens-matter obstructing the passage of the aqueous humor through the spaces of Fontana.
The increasing forms of cataract are roughly divided into four stages. As a rule, they begin in isolated areas, but increase and multiply until all of the lens-substance is affected. The most frequent form is that known as senile cataract.
In the first, or incipient, stage the opacities usually begin in the periphery of the lens. They appear either in the form of spots or of stria, which radiate from the lenticular equator toward the centre of the lens. This condition is known as cortical cataract. In other cases the nucleus of the lens may become quite hazy and opaque, while the periph ery may remain comparatively clear. This variety is ordinarily designated as nuclear cataract. In most instances, however, the two forms, in which both the cortical and the nuclear portions of the lens are affected, are associated.
Clinically, in the stage of development of the cataract the anterior chamber will be found but slightly shallowed or of normal depth, and thc opacities will, by oblique illumination, appear as white or gray streaks and sectors with dots.
In the second stage, or that of ripen ing, the lens is swelled, this being due to the fact that it contains an increased quantity of fluid. The opacities are
more pronounced, while numerous clear spaces are scattered throughout the lens subMance. As a rule, the anterior sur face of the lens has an iridescent, bluish white appearance. The anterior cham ber is shallow. Clear spaces situated in the lens between the iris and the opaque portions of the lens-substance can be recognized by oblique illumination, allowing a shadow of the iris to be cast upon the lens at the side from which the light is thrown.
In the third, or mature, stage the lens has returned to its normal size, this being, in great measure, due to the loss of the lenticular fluids by resorption. The clear spaces in the lens-substance are replaced by opacities, and the ante rior chamber has regained its normal depth. The iris fails to cast a shadow. The lens presents a dull-gray or waxy appearance, and its anterior face is seen to be situated on 4 level with the pupil lary margin of the iris. Should the pupil be artificially dilated, it will be found that the red reflex from the fundus, which can be dimly obtained while the cataract is in its immature stage, is lost.
In the fourth, or hypermature, stage, as a rule, one of two changes occurs: either the cortical substance disinte grates and becomes fluid, while the nucleus remains hard,—so-called "Mor ganian cataraet,"—or the broken-down cortical substance becomes more greatly inspissated and dries into a hard and somewhat flattened MaSS.
In hypermature cataract the anterior chamber is of normal depth, the iris fails to cast any shadow-, and the surface of the lens appears either homogeneous or exhibits irregular dots in the situation of the ordinary physiological sectors. If, however, the overripening process be more advanced, fait v and calcareous de generation occurs in the lens and its cap sule, the anterior chamber becomes deeper than normal, and tremulousness of the iris can be seen.
In Morganian cataract the nucleus may sink to the bottom of the liquid contents contained within the lens-cap sule, the walls of the capsule may come in contact with one another, and the volume of the lens-mass become increas ingly smaller until nothing but a thin, transparent membrane remains: so called "membranous cataract." Practically, according as the dimen sions of the nucleus of the lens vary, a cataract is spoken of as hard or soft. When there is no hard nucleus the cat aract is said to be soft; so that, as a rule, all cataracts occurring in persons under 35 years of age fall under this category. In older subjects, however, the lenticular nucleus is larger and more or less sclerosed; so that opacities occur ring in such persons are designated as hard cataracts, although the cortices of such lenses may be quite soft.
In some senile cataracts the general sclerosis becomes so pronounced that the entire lens is involved in it. In such a condition the cataract, as a rule, ap pears a dense, reddish brown and mark edly translucent. This variety- is usu ally termed "black cataract."