Anterior Polar Cataract Research Articles

Microphthalmia-Congenital Anterior Polar Cataract: An Autosomal Dominant Syndrome

A condition is described which is characterized by microphthalmia and congenital anterior polar cataract, transmitted in an autosomal dominant fashion.

Congenital Anterior Polar Cataract: A Review of 63 Cases

Sixty-three patients with congenital anterior polar cataracts seen over a period of 15 years at The Children's Hospital, Boston, were reviewed to determine their clinical course and visual outcome. Over one-third of the patients were found to have strabismus, refractive anisometropia, or some form of amblyopia. Seven other patients had additional ocular pathology which affected their visual prognosis. One patient manifested progressive lens opacification that eventually warranted cataract surgery. These findings suggest a less benign prognosis for congenital anterior polar cataracts than has generally been described. In our series early ophthalmological examination did not always allow us to forecast later visual disability. We therefore recommend regular follow-up of all children with anterior polar cataracts until a secure assessment of vision can be made.

Autosomal dominant anterior polar cataracts associated with a familial 2;14 translocation.

We describe a family in which autosomal dominant anterior polar cataracts are segregating in four members over three generations with an apparently balanced reciprocal translocation between chromosomes 2 and 14....

Dominant cataract mutations and specific-locus mutations in mice induced by radiation or ethylnitrosourea

In a combined experiment, dominant cataract mutations and specific-locus mutations were scored in the same offspring. In radiation experiments, a total of 15 dominant cataract and 38 specific-locus mutations was scored in 29396 offspring. In experiments with ethylnitrosourea (ENU), a total of 12 dominant cataracts and 54 specific-locus mutations was observed in 12712 offspring. The control frequency for dominant cataracts was 0 in 9954 offspring and for specific-locus mutations 11 in 169955 offspring. The ratio of radiation-induced recessive visible to dominant mutations was about 2.5:1. The difference was even more pronounced for ENU-induced mutations. The ratio of recessive visibles to dominant cataracts for chemically induced mutations in spermatogonia was about 5.4:1. The two characteristic features of radiation-induced specific-locus mutations— the augmenting effect of dose fractionation and the quantitative differences in the mutation rates between spermatogonial and post-spermatogonial stages — can also be demonstrated for the induction of dominant cataracts. The dominant cataract mutations recovered can be categorized into 7 phenotypic classes: total opacity, nuclear and zonular cataract, nuclear cataract, anterior pyramidal cataract, anterior polar cataract, anterior capsular cataract, and vacuolated lens. The largest class of mutations, a total of 11, affected the anterior polar region, while the number of total opacities in both experiments was 5. The only noteworthy difference observed between the radiation- and ENU-induced mutations recovered was that, of the 2 radiation-induced total lens opacities, both were associated with an iris anomaly and microphthalmia whereas the ENU-induced total opacities were not. Mutations at all 7 specific loci were observed in these experiments after exposure of spermatogonia to radiation or ENU. ENU induced twice as many mutations at the p locus and 3 times as many mutations at the d locus as did radiation. In contrast, ionizing radiation induced 4 times more mutations at the s locus than ENU. Double mutants ( d- se) were observed only in radiation experiments. These observations support our earlier conclusions that chemically induced DNA lesions in spermatogonia and the resultant mutations are different from those induced by radiation. The advantage of a large sample of induced dominant defects in one body system for the direct estimation of the genetic risk to the human population is discussed.

Anterior Polar Cataracts Associated With Bilateral Retinoblastoma

A 13-month-old girl had bilateral congenital cataracts at four days after birth. At age 4 months the cataract in her right eye was observed by her mother to enlarge and change in color. Examination of the fundus disclosed a large yellow mass. The eye was subsequently enucleated and histopathology confirmed the diagnosis of retinoblastoma associated with anterior polar cataract. On routine examination at age 13 months multiple tumors were observed in the fundus of the left eye, and were successfully treated by external beam irradiation. This is the second case reported.

Operation einer kongenitalen Katarakt bei einem Sibirischen Tiger

A cataract operation in a young Siberian tiger is reported. This 5-month-old tiger, presenting with blindness, showed bilateral residual pupillary membranes and anterior polar cataracts combined with nuclear cataracts. After unilateral intracapsular extraction of the lens, the tiger adapted well to the improvement in sight and behaved almost like an animal with normal vision. The animal died 3 months post-operatively from unknown cause. Histological examination of the aphakic eye showed, at the site of operation on the cornea, an intact epithelium with discrete infiltration of the stroma together with low-grade vascularisation. In the eye not treated operatively, both an anterior polar cataract with adherent pupillary membrane strands and a central cataract were seen. Of particular note, when comparing this large wild cat with the domestic cat, was the marked development of the tapetum lucidum (up to 30 cell layers).

Anterior polar cataract and lysosomal alterations in the lens of rats treated with the amphiphilic lipidosis-inducing drugs chloroquine and chlorphentermine

Chronic treatment of rats with the amphipilic drugs chloroquine and chlorphentermine caused prominent anterior polar cataracts in virtually all rats. The basic pathologic changes underlying these cataracts were: (a) degeneration of anterior polar and sutural endings of cortical lens cells and (b) multilayered proliferation and invasion of epithelial cells into the anterior polar cortex. Ultrastructurally cortical lens cells displayed various patterns of degeneration, finally undergoing complete liquification. Liquified lens substance was phagocytosed by invading epithelial cells. Cortical lens cells and epithelial cells contained numerous lipidosis-like (lamellated) inclusions, which possessed cytochemical acid phosphatase activity. The present drug-induced lenticular alterations are interpreted as the direct or indirect consequences of a drug-induced disturbance of polar lipid metabolism in the lens.

Anterior polar and posterior subcapsular cataract in a patient with retinitis pigmentosa: a light-microscopic and ultrastructural study

The cataractous lens of a patient with retinitis pigmentosa has been studied by electron microscopy. The anterior polar and posteroir subcapsular opacities showed common ultrastructural features. Large areas of disruption of the lens fibre pattern were observed which showed an increase in the number of fibre membranes per unit area. In many regions an elaborate and regular folding of membranes was noted which produced complex “figure-of-eight” and “tramline” patterns, as well as membranous lamellar bodies. Masses of Morgagnian globules were also identified. The findings are discussed in relation to previous reports of anterior polar cataract and a tentative mechanism has been proposed to explain some of the changes observed.

Morphology of a hereditary cataract in the rat

Eyes of a strain of Wistar rats with an X-ray-induced cataract mutation were subjected to clinical and histological investigation, beginning postnatally. Anterior polar cataract formation and anterior displacement of the lens nucleus were the earliest clinical indications of the disease, which eventually affected the entire lens and may have been initiated by an inflammation of the anterior ocular segment. The polar cataracts, first seen in newborn animals, were manifestations of an epithelial overgrowth which, by 3 weeks postpartum, was accompanied by overproduction of the capsule. In 3-week-old animals, suture-associated vacuoles were observed in the posterior lens cortex. These vacuoles, which appeared to have originated primarily by a widening of the intercellular space, tended to disappear. They were soon replaced by others which were caused largely by swelling and rupture of the outer cortical fibers. With swelling of the lens, the posterior capsule became thinner, and, in some cases, ruptured. In most lenses, however, the capsule remained intact. In these, cortical vacuolization and clouding was followed by opacification at the nuclear periphery which rapidly intensified and spread outward. The anomalies described here resembled certain developmental lens abnormalities reported in humans and other animals.

Anterior polar pyramidal cataract. Presenting as an anterior chamber foreign body.

Anterior polar pyramidal cataract. Presenting as an anterior chamber foreign body.

Cataracts and abnormal proliferation of the lens epithelium in mice carrying the Cat Fr gene

In mice carrying the dominant gene Cotaract-Fraser (or Shrivelled) pyknosis of the nuclei of the lens fibers is followed by cytoplasmic abnormalities and eventually complete destruction of the main lens fiber mass. The process begins at 14 days of embryonic life and is continuous throughout life. In addition to this degeneration of the fibers, the anterior epithelium becomes abnormal postnatally leading to anterior polar cataracts. The epithelial cells show unusual proliferative activity and form multiple layers of atypical cells. The cell masses may become very large and sometimes seem to infiltrate the remainder of the lens fibers. Occasionally whorls of spindle-shaped cells are present. The anterior capsule is much thicker than normal and irregular clumps of capsule-like material are found in between the epithelial cells. It is possible, that the changes in the anterior epithelium and capsule are secondary to the damage found in the fibers.

Morphogenesis of the eye lens in a mouse strain with hereditary cataracts.

AbstractMice carrying the gene “Shrivelled, ” also known as “Cataract‐Fraser” or “Cataracta hereditaria subcapsularis, ” invariably develop lens opacities which are visible when the animals open their eyes on the fourteenth postnatal day.Lens development in normal and mutant embryos is the same until day 14 of gestation. At this stage the nuclei of the lens fibers in the controls are large and vesicular with prominent nucleoli. In the mutants the centrally located nuclei are smaller and darker with indistinct nucleoli. The nuclei of normal fibers remain large and open even after birth; those in the mutants continue to undergo pyknosis after passing through the equatorial zone in the regular fashion. The nuclear degeneration is followed, with a delay of about 24–48 hours, by swelling and vacuolization of the fibers concerned. In the adult the lens core forms an amorphous eosinophilic mass or may partly be resorbed. The cortical fibers remain normal. Anterior polar cataracts develop: the epithelial cells proliferate to form multiple layers of atypical cells, surrounded by lens capsule‐like material.The fiber degeneration may be caused by precocious cessation of protein synthesis after the cell nucleus becomes defunct. The late epithelial aberrations may be secondary to the changes in the underlying fibers and are possibly related to the reactivation of cell replication in the central part of lens epithelium seen after traum.

Lens-specific antigens and cytodifferentiation in the developing lens

Polycrylamide gel electrophoresis of chicken lens proteins showed 17 crystallins, divided over three groups. Within each group physicochemical heterogeneity was combined with (partial) immunological homogeneity. It is assumed that more than one gene is involved in the synthesis of any crystallin species. During development of the chicken embryo, α-crystallin was first demonstrated by immunofluorescence in centrally located lens fibers at 3 days. At 8 days the epithelium became positive and the fibers lost some fluorescence. This continued until in 5-week-old chickens the lens core was negative. Lens placode cells showed immunofluorescence for δ-crystallin at 52 hours, mainly in their basal parts. The reaction gradually spread and at 3 days the entire lens was positive. From 8 days on the epithelium reacted progressively weaker, but the fibers remained positive. Five weeks after hatching, epithelium and cortex were negative, while the center still showed strong fluorescence. The behavior of β-crystallin was intermediate between that of the other two. Immunoelectrophoresis suggested a differential production onset for the components of each single crystallin type. Under normal conditions no crystallins were found outside the lens. Therefore, crystallin synthesis occurs after placode formation has taken place and must be restricted to the lens itself. Autoradiography after 3H-thymidine treatment indicated that all placode cells still replicate, though some already produce crystallins. A generation time of 8 to 10 hours was determined with an M phase of 30 minutes, an S phase of 6 hours, and a G2 of 2 ½ hours. During DNA synthesis the nuclei were located in the basal parts of the cells, and for mitosis they migrated to the lumen. Autoradiography after 3H-glucosamine application suggested that the placode cells take active part in the synthesis of the basement membrane interposed between lens rudiment and optic cup. This membrane later becomes the lens capsule, and in mice with the “shrivelled” gene, abnormal masses of anterior epithelial cells also clearly produce extra capsule material. This results in anterior polar cataracts. Several of the above findings are in disagreement with some of the current theories on the regulation of lens differentiation. No substitutes are presently offered, however.

Congenital eye defects in the mouse. I. Corneal opacity in C57black mice.

AbstractCorneal opactities are observed in a small percentage of C57Black mice. Discrete central opacities are found in eyes of normal size; more generalized opacities are found in eyes which are reduced in size, although large enough to protrude through the eyelids. Corneas with discrete opacities are characterized by a gap in the stroma, and disorganization of the overlying epithelium. Similar stromal defects are found in corneas with more generalized opacties, and, in addition, cornea and iris are continuous along their stromal components. Either anterior polar cataract or anterior lenticonus, defects involving the anterior surface of the lens, are almost invariably found in association with the corneal opacities.Study of early lens and corneal development in C57Black embryos implicates prolonged attachment of the lens vesicle to the superficial ectoderm in the genesis of the corneal opacities. The persistence of the lens stalk serves as a barrier to migration of the mesenchyme involved in formation of the corneal stroma. Migration of the mesenchyme destined for a role in development of the stroma of the iris may also be hindered. Separation of the lens vesicle from the superficial ectoderm takes place eventually, but stromal development remains defective. Disorganization of the corneal epithelium appears to be a secondary consequence of the defective stroma. Anomalies of the anterior surface of the lens appear to result from problems associated with the abnormal separation of the lens vesicle from the superficial ectoderm.

Anterior Polar Cataract: Electron-microscopic evidence of collagen

Anterior Polar Cataract: Electron-microscopic evidence of collagen

ANTERIOR LENTICONUS IN FAMILIAL HEMORRHAGIC NEPHRITIS. DEMONSTRATION OF LENS PATHOLOGY.

The lens pathology of bilateral progressive anterior lenticonus in familial hemorrhagic nephritis (Alport's syndrome) is reported in this paper. The lens pathology consists of thinning of the lens capsule, decrease of the number of lens epithelial cells, bulging of lens substance, and minimal subcapsular cataract at the anterior pole of both lenses. Alport's syndrome has been known since 1912 as hereditary familial congenital hemorrhagic nephritis. 1,2,3 The earliest reports of the syndrome found were by Guthrie in 1897 and 1902. 4,5 In its initial description it was thought to include only progressive nephritis with albuminuria and hematuria and progressive congenital nerve deafness. The nephritis characteristically leads to early death in males while females usually have a normal life expectancy. 2,6,7 Lens involvement with anterior lenticonus, spherophakia, anterior polar cataract, and posterior cortical cataract has later been described in association with the syndrome. 6 It is interesting to note that lens

Gross remnants of the pupillary membrane, anterior polar cataract and microcornea in a mother and her children.

Gross remnants of the pupillary membrane, anterior polar cataract and microcornea in a mother and her children.

TREATMENT OF IMMATURE CATARACT.

Non-progressive cortical opacities are very rare. The opacity accompanying congenital coloboma of the lens, the partial cortical cataract caused by the adhesion of a retained or acquired pupilary membrane and some forms of traumatic partial cataract do not progress. The anterior punctate cortical cataract, the posterior cortical cataract and the form of zonular cataract, in which the zone is situated well in the cortex of the lens, are extremely slowly progressive. Traumatic partial cataracts, with or without perforation of the capsule, sometimes become stationary and in a few cases the opacification partly disappears. Anterior and posterior polar cataracts are almost always stationary. The small white congenital cataract which occupies the center of the lens and apparently includes only those fibers that are formed during the second stage of development of the lens, the axial congenital cataract and a few cataracts with mixed opacities, are stationary or nearly so. Some forms