ACTA O P H T H A L M O L O G I C A V O L . 4 1 1 9 6 3

From the Eye Hospital, University of Helsinki (Head: Prof . S. Vannas, M . D.)

VISIBILITY OF ANTERIOR BORDER-RING OF SCHWALBE

IN CONGENITAL CORNEAL ANOMALIES, TUMOURS OF THE

LIMBUS AND DENTAL ANOMALIES”)

BY

Henrik Forsius

Embryotoxon corneae posterius (ECP), dysplasia marginalis posterior or a visible prominent anterior border-ring of Schwalbe consists of a whitish-grey margin of the limbus on the posterior surface of the cornea, present as a rule only temporally. The difference between physiological ECP and the form seen in association with anomalies of the iris and cornea is often one of degree. The former type is seldom observable without a slit-lamp, and very seldom involves the whole outline of the limbus, while the latter frequently extends further onto the cornea and is sometimes visible with the naked eye from a distance of several metres. The heredity of ECP and its occurrence in an isolated population in which the incidence was high (Forsius, Eriksson & Fellman), its frequency in patients with high hyperopia as compared with the frequency in a normal population - 12 per cent (Forsius) - and the correlation between anomalies of the iris and ECP (Forsius & Eriksson) have been dis- cussed in previous papers.

ECP has also been described in association with various corneal anomalies. ECP was observed in association with megalocornea by Falls and by Burian,

Rice and Allen. In the cases in question, multiple ocular anomalies were in- volved. Furthermore, the anomaly has been described in cases with congenital changes of the iris in which a rise of the ocular pressure had caused enlarge- ment of the cornea.

In the ordinary dominant or x-linked or recessive inherited form of megalo- cornea, ECP does not appear to be a feature of the clinical picture. To the best of my knowledge, there is only one report (Rud) of a gonioscopically very prominent anterior border-ring of Schwalbe in this condition. Among patients with microcornea ECP was observed by Friede, Kubik, Rieger, Theodore,

*) Received October 10th 1963.

97 Acta Ophthalmol. 42, I 7

Paganelli and Collier. Furthermore, i t may be mentioned that v. Grosz ob- served Keratoconus in a woman whose brother had ECP and other ocular anomalies.

ECP sometimes occurs in conjunction with ptosis (Biozzi & Lugli, Theodore, Paufique, Etienne & Bonnet, Collier), severe myopia (Friede, Lemmingson & Riethe, Burian, Rice and Allen, Collier) or high degrees o f hyperopia (Forsius). Furthermore, cases have been reported in which ECP and anomalies of the ocular fundus were present, e. g. hypoptasia of the optic nerve (Collier), fibrae medullares (Gluh), atrophy of the retina (Falls), unilateral pseudoglioma and iridoschisis (Waardenburg).

At the same time other deformities may be present, e. g. harelip (in a sibling of the family) (Collier), dental anomalies (Rossano, Schmidt, Rejchrt & Miksa, Kittel, Lemmingson & Riethe, Busch, Weiskopf & Busch, Lemmingson), status dysraphicus (v. Grosz) and hydrorefihulus (Bollack, Voisin & Camps).

Mentat retardation has sometimes been reported in subjects with ECP or in relatives of such subjects (Rieger, Schmidt, Collier). In Crouzon’s disease ECP was observed by Paganelli, Calmettes, Amalric & Bessou and Collier. In ad- dition, Collier observed the anomaly in Paget’s disease, Marschesani’s syn- drome and Hullerman-Streiff’s syndrome. Of two patients with Hallerman- Streiff‘s syndrome described by Forsius & de la Chapelle, one had deep peri- pheral opacities in the cornea. Furthermore, ECP was present in one out of three patients with keratoconus posticus (Forsius & Metsala), and Collier described ECP in one patient with facial angioma and in another with a juxta- pafiillary naevus and bilateral inguinal hernia. Braendstrup described a man with ECP, bilateral impairment of hearing and inguinal hernia.

SERIES

Megalocornea Case 1. Bjorn L., 51, male. In both eyes the corneal diameter was 13 mm and re-

fraction 43.75 D horizontally. The pupils were dislocated 2 mm nasally upwards. The ocular pressure was 8-11 mm Hg. Vision was previously good, but during an observa- tion period of over three years, central parenchymal opacities, varying in appearance, developed and refraction was impaired. Astigmatism increased in the right eye by 1.25 D, in the left by 1.5 D, and the cylinder axis was turned 12’ in the right eye and 5 5 O in the left. Corneal refraction increased by 0.5 and 0.25 D, respectively. At the last examination vision was 0.5 with cyl. 4- 2 D ax 155O in the right eye and 0.2 with + 1.5 D cyl. + 3 ax 20° in the left. A narrow arcus senilis was observable in the upper and lower quadrants. ECP was absent.

Case 2. Vaino L., 48, male. The corneal diameter was 13 mm, the corneal re- fraction 44.5 D. A narrow arcus senilis was observable in the upper and lower quadrants with ordinary local illumination, and around the whole limbus in the slit- lamp. There was no definite prominent ECP. Gonioscopically, small peripheral ante- rior synechiae were detectable in many sites. The iris was hypoplastic. Iridodonesis

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was present. At 4 o'clock in the right eye there was a peripheral opacity of the lens. which had been detected as long ago a s 1929. A persistent hyaloid artery extended almost to the posterior surface of the lens. Ocular pressure was normal, vision good. Slight hyperopia was present.

Case 3. Markku S., 6, male. Mental development was retarded. Refraction was i- 0.5 D cyl. + 1.5 D ax 90'. The corneal diameter was 14.0 mm in the right eye and 13 nim in the left. The cornea appeared to be thin. The anterior chamber was deep. The lens was clear, and the ocular fundus normal. Biomicroscopically no ECP was observable, but gonioscopically this anomaly was seen around the whole limbus. There were abundant iris synechiae to the trabecular zone.

Case 4. Vain6 H., 51, male. In the last few years increasing myopia has been ob- served. Right eye: Vision 0.3 with - 6.25 D s cyl. - 1.0 D ax 90'. The corneal diameter was 13 nim and corneal refraction 44.75:45.25 D (horizonta1ly:vertically). No ECP was observable. Slight hypoplasia of the iris was present. Left eye: Vision 0.25 with -4.75 D cyl. - 1.0 D ax 90'. Otherwise the findings were the same as in the right eye.

Case 5. Irina A., 2, female. According to a psychiatrist, her mental development was retarded by 7 months. The left eye showed a convergent downward squint. The corneal diameter was 12.5 mm. ECP was absent. The iris was normal, and the ocular tension and refraction were normal.

Borderline cases of megalocornea Case 6. Vaino Lal., 54, male. Two siblings were said to have large corneas, 8 other

siblings normal eyes. The patient's two children were also said to have large corneas. Right eye: Vision 1.2 with + 1.5 D. The corneal diameter was 13 mm, corneal re- fraction 42.0:41.75 D. ECP was present. The pigmentation of the iris was poor. Left eye: Vision 1.3 with + 1.0 D. The corneal diameter was 12.5-13 mm, corneal re- fraction 41.5:42.25 D. ECP was present. The pigmentation of the iris was poor. Gonio- scopically the chamber angle was patent. There were no iris synechiae.

cyl. - 1.5 D ax 0'. The corneal diameter was 12 mm and refraction 40.5:42.5 D. ECP was present a t 1-1 1 o'clock, with abundant iris synechiae, in particular nasally and below. Between 5 and 6 o'clock the iris was split into two layers, between the sphincter and the ECP. The iris was hypoplastic. The pupil was somewhat dislocated downwards (Fig. 1). Left eye: Vision 0.9 with -4.5 cyl. - 1.5 D ax 0'. Corneal refraction was 40.75:41.5 D. Otherwise the cornea and iris were as in the right eye, but iris synechiae were present only below. Glaucoma had recently been diagnosed.

Blue sclerae

and son) were more closely examined.

Case 7. Miina M., 31, female. Right eye: Vision 0.9 with - 1.0 D

In a large family with fragilitas ossium and blue sclerae 2 subjects (father

Case 8. Lauri L., 48, male. Vision was good in both eyes, and the patient was emmetropic. He had blue sclerae. The corneal diameter was 12 mm, refraction 39.75:40.25 D in the right eye and 40.25:41.25 D in the left. No ECP was observable biomicroscopically, but gonioscopically a smooth arc was seen on the posterior surface of the cornea, close to the chamber angle. The base of the iris was prominent, and the apex of the chamber angle was partially covered. The corneoscleral membrane was broad. A marked arcus senilis was present around the whole limbus. The cornea was normal in thickness. The iris was translucent. An audiogram showed marked de- generation of the inner ear.

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Case 9. Esko L., 10, male. He had had fractures three times. Vision was good in both eyes. He was slightly hyperopic, and had blue sclerae. The corneal diameter was 1 1 mm and corneal refraction 40.5:41.75 D ax 72’ in the right eye and 40.5:41.5 D in the left. The cornea was thin. The corneoscleral membrane was broad. In one eye there was a small remnant of the pupillary membrane. ECP was absent.

Cornea plana Case 10. Seija K., 19, female. The patient was the third of six children. The two

youngest died in infancy. She stated that she had had poliomyelitis at the age of 4. She had a left-sided limp. Her vision had always been poor. Glaucoma was observed when she was 15 years old. Nystagmus was present. The right eye had been operated upon four times, and the left eye once. Hearing was impaired. The audiogram showed a middle-ear hearing defect, combined with a definite cochlear component. Otologist’s diagnosis: Otosclerosis? Adhesive otitis?

Right eye: The corneal diameter was 12 mm, and refraction 40:41.25 D. The limbus was normal and the cornea was of normal thickness. ECP was present at 3-10 o’clock. There were no anterior synechiae. The pupil was small and somewhat dislocated temporally. The sphincter pupillae was normal. The anterior layer of the iris was hypoplastic. There were peripheral holes (postoperative?) in the iris a t 12 and 7 o’clock. Left eye: The corneal diameter was 12 mm, refraction 37:35.5 D. The cornea was somewhat thicker than normal. There were central opacities in the middle layer of the parenchyma and of Descemet’s membrane. ECP was present at 1-11 o’clock. Temporally, in particular, the arc was broad, and both at this site and at 6 o’clock there were some anterior iris synechiae. The iris was markedly hypoplastic, and ex- hibited holes close to the periphery at I1 and 12 o’clock. Around these, only the pigment layer of the iris was visible. The pupil was small, slit-like and dislocated downwards.

Case 11. Tapio S., 1 1 , male. The patient was the eldest of three children. The siblings were normal. His mental development was retarded, and he had hallux valgus and pes planus. Slight ptosis was present in both eyes. The pupillary distance was 67 mm. Right eye (Fig. 2 a): Corneal diameter 11.5 mm, refraction 36.5 D in the axis 20’ and 39.5 D at 120’. On the posterior surface of the cornea, about 2 mm from the limbus, there was a greyish-white area extending right round the limbus, to which the whole anterior layer of the iris was adherent. The posterior layer of the iris was separated from the anterior layer everywhere except at the margin of the iris and at a few other sites, and the pigment layer formed an ectropium uveae, about 1 mm in breadth. At the margin in the pigment layer there were several holes, measuring 1-3 mm, which had not been observable in 1958. The pupil was large. At many siter the lens was not in contact with the iris. The ocular fundus exhibited choroidal sclerosis. The papilla was pale, and its lower margin was prominent. Refraction was emmetropic. Tension was 19 mm Hg. Left eye (Fig. 2 b): The corneal diameter was 11.5:11 mm, refraction 39:36 D. There was a broad ECP around the whole limbus, though not as broad as in the right eye. There was a threadlike anterior synechia to the ECP at 4 o’clock, and a broad synechia to the periphery at 8-9 o’clock. The pupil was dislocated to the latter site. In this area the anterior layer and the pigment layer of the iris were only in contact at the margin of the pupil, and at this site the pigment layer formed an ectropium uveae. The iris was hypoplastic. The lens was clear. The ocular fundus exhibited choroid atrophy. The papilla was oval, and fibrae medullares were present. There were small spots of pigmentation in the macular region. Refraction was + 8.5: + 6.5 D (horizonta1:vertical). Tension was 23 mm Hg.

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Fig. 1. Case 7. Right eye of a 3-year-old woman. Corneal diameter I2 mm. ECP between 1 and 11 o’clock, with iris synechiae. Partial iridoschisis between 5 and 6. EIypoplasia

of the iris.

Fig. 2. Case 11. An 11-year-old boy with cornea plana and retarded mental development a) Right eye: ECP all around the limbus. The anterior layer of the iris entirely

adherent to the cornea, hut ful l of holes through which the pigment layer of the iris 1 mm deeper is observable. The pigment layer is in contact with the anterior layer of the iris mainly at the ECP, where the iris tissue ends (partial aniridia).

h) Left eye: A broad ECP around the whole limbus, with thread-like anterior syne- chi2e. Corectopia and hypoplasia of the iris.

Fig. 3. Case 13. A 6-month-old, mentally retarded boy with cheilognatouranopalatoschisis and a coloboma of the iris nasally below, partially covered by a pericorneal connective

tissue membrane.

Fig. 4 . Case 13. Right eye of the same patient as in Fig. 3. Corneal diameter 9 mm. Cornea

adherent to the inner ocular angle. Hypoplasia of the iris. The lens is opaque.

F i g . 5. Case 16. An 15-year-old girl with left-sided facial hypoplasia and dental anomalies. Corneal diameter 9 mm to the left. Corectopia. From 1-8 o’clock around the limbus a subconjunctivad hairy elevation extending laterally to the outer ocular angle. Thick

connective tissue adhesions around the rectus medialis muscle.

Fig. 6. Case 17. Right eye of a 9-year-old feeble-minded girl. Large pupil since birth. The sphincter functions only from 12-3 and 7-5 o’clock. The posterior pigment layer is almost entirely lacking from 3-6, and thin from 8-12. No ECP. Refraction - 10.5 D.

Fig . 7. Case 17. The same patient as in Fig. 6. Dental anomalies in both maxillae.

Fig. 8. Case 19. Left eye of a 1.5-year-old boy with left-sided facial atrophy and dental anomalies. Corneal diameter 7 mm, corneal refraction 38.5:42.5 D ax 85'. Iris colo- boma as far as 7 o'clock. A bridge of iris stroma extending over the coloboma close

to the chamber angle.

Border-line cases of cornea plana Erja M., 2, female. Birth weight 3900 g. The mother’s pregnancy had

been without complications. The patient was examined for the first time a t the age of 2 months. Roentgenologically there was a shadow in the upper mediastinum. En- larged thymus? Right eye: Corneal diameter 11 mm The cornea was normal in thick- ness. Corneal refraction was about 38.39 D. -4 conspicuous ECP was present around the whole limbus 1-2 mm from the latter. Inside this ring the posterior surface o l the cornea was clear, but outside it a thin opacity was observable, extending as far as the limbus. Thin, tent-shaped iris synechiae extended from both the periphery and the centre to the ECP around the whole of the limbus. The synechiae extending in the peripheral direction were in contact with the underlying iris in front of the base of the latter leaving part of the anterior chamber visible even in the extreme peri- phery. The pupil was small and dislocated inwards and upwards, and drawn out in this direction. Limbally of the pupil a thickening of the otherwise thin iris parenchyma was discernible in this area. Ocular tension was 50 mm Hg. The lens and the ocular fundus were normal. Left eye: Corneal diameter 11 mm and refraction about 36:39-40 D. Around the whole limbus a n ECP was observable to which iris synechiae of the same type as in the right eye extended. The pupil was slit-like, and measured 3 mm in the direction 12-5 o’clock. The iris tissue was as in the right eye. The anterior chamber was low. Ocular tension was 40 mm Hg. The lens and the ocular fundus were normal. A cyclodialysis was performed in the left eye. Two years later corneal refraction was 39:40 D in the right eye and 39.5:42.5 D ax i0” in the left. and tension was 20 and 18 mm H g with pilocarpin-medication. The patient died some time later of pneumonia.

Case 12.

Aiaomalies of the iris and cornea combined with extmbulbar tumours and bone defects

Case 13. Pertti K., 6 months, male. The mother suffered from renal disease during the pregnancy. The patient was an only child. His birth weight was 2710 g. He had cheilognathouranopalatoschisis (Fig. 3) , nystagmus and bilateral microphthalmus. Right eye (Fig. 4): Corneal diameter 9 mm. Nasally in the lower quadrant the limbus was covered for 2 mm by a thick connective tissue membrane, which made the eye adhere to the inner ocular angle, in which a polypus-like formation was discernible. Tem- porally the border between the sclera and the cornea was partially translucent and tinged with blue over an area 2 mm broad. Inside this, there was a broad ECP at 7-12 o’clock, to which the iris was adherent. Ocular tension 26 mm Hg. The anterior layer of the iris was in part highly atrophic. The pupil was drawn downwards to the limbal tumour, and its lower margin was adherent to the latter. There was a thin iris synechia to the lens, which was in part calcified. The anterior chamber was normal in depth. The deeper parts of the eye were invisible. Left eye: Corneal diameter 7 mm. Tension 18 mm Hg. The same changes as in the right eye was present as the mirror image. The lens was, however, clear and dislocated nasally. About ten round dots, measuring about l / 3 mm, were visible in the vitreous body. There was a large, deep coloboma of the uvea, involving the papilla. At the age of 2 years, the patient’s mental development was found to be retarded, when allowance was made for his ocular defects.

Case 14. Riitta O., 15, female. Right eye: Small superficial opacities were present in the central part of the cornea and in its posterior surface. Small remnants of the pupillary membrane were discernible. Temporally the conjunctiva exhibited a some-

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what rough, pigmented, richly vascularized tumour. This was extirpated, and found to be a naevus of compound type. Temporally in both eyes there were symmetrically situated ECPs.

Case 15. Borje B., 15, male. Vision had always been poor in the right eye, and the latter was exophthalmic. The patient had been operated upon three times since the age of 5 for a progressive fibrolipoma, which extended medially to the limbus and deeply into the orbit. Right eye: Vision 0.01 E. The cornea was clear and the pupil central. The structure of the iris was irregular. Below, remnants of the pupillary membrane were discernible. In the upper and lower quadrants of the iris blood vessels were clearly visible. The lens and ocular fundus were normal. ECP was absent. Left eye: Vision 1.0 E. No symptoms.

Case 1G. Eeva V., 1 5 , female. The great toe was a little shorter than the second and third toes. The thorax was normal. The mandible was small to the left, and dental anomalies were present (Fig. 5 ) . The otorhinolaryngological findings were nor- mal, and neurologically there was nothing noteworthy. The left eye had a convergent squint. Nystagmus was present. Right eye: Vision 0.G E. Corneal diameter 11 mm, refraction 46.5:47.5 D. At a site 5 mm laterally downwards from the limbus there was a subconjunctival, elevated tumour measuring about 1 cm. ECP was absent. The iris tissue was prominent between the pupillary margin and the periphery at 2 o’clock. The ocular fundus was normal. Left eye: Vision 0.01. Corneal diameter 9 mm, re- fraction about 45 D. A superficial opacity of the corneal parenchyma was present centrally, where the cornea was thinnest. Blood vessels passed laterally of the limbus to the opacity at the same depth as the deepest of the latter, i. e. one-third of the thickness of the cornea. ECP was absent. The pupil was dislocated nasally upwards by 2 mm and drawn out in this direction where the parenchymal layer of the iris formed a pit close to the pupillary margin, the bottom of which was covered by a white tissue. The normal pigment margin at the pupil was absent. The sphincter was clearly visible through the hypoplastic iris. The lens and ocular fundus appeared to be normal. The horizontal length of the ocular fissure was short and the nasal portion of the lower lid was dislocated downwards. Around the limbus, between 1 and 8 o’clock, there was a firm subconjunctival elevation, which extended laterally to the outer ocular angle. There was a convergent squint, and the eye could not be turned beyond the median line. The surface of the tumour was hairy. An operation was performed, most of the tumour, which was free from the rectus temporalis muscle, being extirpated. Histologically, collagenous and adipose tissue were observed. Later, retroposition of the rectus medialis muscle was done. Around the muscle, thick con- nective tissue adhesions were present, which mechanically impeded the movement of the eye.

Case 17. Raili S., 9, female. The patient was the elder of two siblings. Birth weight 2270 g. She was given oxygen treatment for six days. She was feeble-minded. The thorax was narrow and ridge-shaped. Dental anomalies were present in both maxillae (Fig. 7) . There was choanal atresia. Right eye (Fig. 6): Refraction - 10.5 D. The cornea was clear and normal in size. The pupil was larse (observed already at birth). The sphincter functioned only in an area between 12 and 3, and between 7 and 8 o’clock. Between 3 and G o’clock the pigment layer was almost entirely lacking, and it was thin at 8-12 o’clock. The lens and ocular fundus were normal (myopic conus) ECP was absent. Left eye: Refraction -4 .5 D. Otherwise the eye was normal.

Case 18. Jouni R., 7, male. The parents come from different parts of Finland. They had two children. The younger, a 3-year-old boy, had a defect of the palate and the same deformities of the palate, extremities and eyes (corneal refraction 38.5 and

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38 D resp.) as his brother. Ths mother was otherwise normal, but her corneal re- fraction was 38.5:39.5 D in the right and 39:40 D in the left eye. The eyes of the father were normal, except for a small remnant of the pupillary membrane in the left. ECP was absent. A dacryocystorhinostomy had been performed on the left side some years previously. The patient under discussion had been operated upon for a defect of the palate. His teeth were brown and stunted. He was receiving speech therapy from A. Sonninen, M. D. The arms could not be straightened, an angle of 30' re- maining a t the elbow. The third and fourth fingers and toes were fused, and the great toes were very stunted. The lacrymal canal of the right eye was perforated in spring 1963. The pupillary distance was 60 mm. An alternating convergent squint was present. Right eye: Vision could not be determined. The diameter of the cornea was 12 mm. Corneal refraction was 37.5:38 D ax 90'. Refraction was 4- 4.5 D. ECP was absent. The medial portion of the lower lid was turned somewhat inwards. The iris con- figuration was according to Waardenburg's scale, the colour was 5 in Martin- Saller's scale 1-8. The lens and ocular fundus were normal. Left eye: Vision could not be determined. The diameter of the cornea was 12 mm, corneal refraction was 37:39 D ax 110'. Refraction was + 4.5 cyl. + 1.0 ax 130°. ECP was absent. The lens and ocular fundus were normal.

Case 19. Rauno M., 15, male. The patient had two siblings. Both these and the parents were said to be normal. The patient's constitution was ordinary; no defor- mities of the extremities were present. The left half of the face was smaller than the other, and the teeth in the upper jaw on this side were densely packed and irregular. The patient had bronchial asthma. Right eye. Vision 1.0 (-5.0 D). Corneal diameter 10.5 mm. The iris was greyish-brown (colour 61. Configuration of the iris: The anterior layer exhibited large crypts down to the periphery (configuration Ll). The lens was clear. ECP was absent. The ocular fundus exhibited a myopic conus. Left eye: Vision 0.04 with - 4 D z c y l . - 6 D ax 85'. Corneal diam. 7 mm, corneal refraction 38.5:42.5 D ax 85'. The iris was browner than in the right eye (colour 7 , configuration C1). There was a colohoma of the iris helow ECP was absent. Gonioscopically a slightly pro- minent border-ring of Schwalbe was discernible, in particular below. A bridge of the iris stroma extended over the coloboma close to the chamber angle. No anterior iris synechiae were present (see Fig. 9). There was an accumulation of pigmentation on the lens within the pupillary area. A large uveal coloboma was present. The left eye had a divergent squint of about 20'.

Hearing was good, and the ears were normal in size and shape.

DISCUSSION

In association with the corneal anomalies discussed in the foregoing, an em- bryotoxon corneae posterius w a s sometimes, but no t invariably, observed. Of the 6 patients with megalocornea - corneal diameter 2 12.5 mm - 5 had n o ECP.

Cornea plana is a very r a re anomaly, but in Finland its incidence is rela- tively high. The present author h a s previously described a total of 26 cases (Forsius and Forsius & Lehmann). ECP is not a typical feature in cornea plana, but in 2 ou t of the 26 cases in question described 1961 (E. R. and V. R., Forsius) examinat ion revealed large anter ior synechiae and a microcornea. In the present pape r three new cases of cornea p l ana a r e described (nos. 10, 11

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and 18). A marked ECP was present in two. One of these patients (No. 11) came from the north of Finland, from the same region as 19 of the previous 26 cases. H e differed from the patients previously described, who were other- wise entirely normal, in that he was feeble-minded and exhibited fibrae me- dullares in the ocular fundi. Patient no. 10, with cornea plana, showed de- generation of the inner ear. Thus, both these patients had ectodermal lesions. The third patient (no. 18) had anomalies of the teeth and extremities.

Two of the present patients (nos. 12 and 19) had low values for cornea! refraction, 38.5 and 39 D horizontal refraction, which are on the border-line of cornea plana. (As a rule, the denomination cornea plana is used when corneal refraction is < 3 9 D). In the literature cases have been reported in which ECP has been described as occurring in conjunction with cornea plana, but the data in question do not relate to genuine cornea plana. In a close relative of a subject with ECP, Kraupa measured 38 D.

ECP also occurs in association with highly refractive corneae. Rieger described a case where corneal refraction was 4950.5 D.

The combination microcornea - ECP has often been described in the litera- ture. In the present study two new cases are reported (nos. 13 and 19).

I t is noteworthy that two of these patients (nos. 7 and 11) as well as some described in a previous paper (Forsius 8: Eriksson), exhibited partial irido- schisis.

Of the patients in the present series who had ocular anomalies and tumours of the limbus (nos. 13-16) 2 (nos. 13 and 14) out of 4 exhibited ECP, and of those (nos. 13, 16-19) with anomalies in other parts of the body one (no. 13) out of 5 had an ECP. During the last decades, there has been a trend to define such cases in terms of various syndromes, and to characterize the re- mainder as natypical cases<<. The present cases (16 and 19) may be called atypical cases of dysostosis mandibulofacialis (Weyers & Thier’s syndrome). A somewhat similar disease picture without changes of the iris was described by S. Vannas (1955) in two patients in this hospital. Case 13, too, belongs to the group ,syndrome of the first visceral arch<<. I t seems possible that in this case the condition was due to renal disease in the mother, and should thus be regarded as an embryopathy.

Case 17 exhibited ectodermal lesions, congenital myopia, anomalies of the pigment layer of the iris, feeblemindedness, dental anomalies and choanal atresia. To the best of the author’s knowledge, such a combination of symp- toms has not previously been described.

Case 18 has some features in common with the oculodentodigital syndrome and with Vogt’s syndrome, but in addition the patient had macrocornea and cornea plana. Furthermore, the occurrence was familial.

A visible anterior border-ring of Schwalbe was present in 4 out of 12 cases exhibiting anomalies of the eye alone.

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Our series of anomalies in the anterior part of the eye has been described in two different papers. The first paper comprised 27 cases in which anomalies of the iris were predominant (Forsius & Eriksson). The present study deals with 19 cases in which corneal and other anomalies were predominant. That the series was classified according to whether an anterior border-ring of Schwalbe was visible or not is mainly due to the fact that the author has been interested in this anomaly for some ten years and therefore recorded its occur- rence in cases examined by him.

The embryology of the chamber angle is far from being understood, and it is complicated because ectodermal and mewdermal tissues meet and act as mutual inductors at this point. Therefore, it is by no means surprising that this ring may become conspicuous in anomalies both of mesodermal and ecto- dermal origin. From the standpoint of differential diagnosis the occurrence of ECP is of no major significance. If a marked ECP is present, however, there is reason to measure the ocular pressure and to examine both eyes goniosco- pically, since it is possible that the border-ring is situated more peripherally in the other eye and is not seen in the slit-lamp, and the chamber angle may be obstructed by iris synechiae.

S U M M A R Y

The relationship between a visible anterior border-ring of Schwalbe or em- bryotoxon corneae posterius (ECP) and various ocular anomalies in 19 patients is discussed. Of 6 patients with megalocornea, one had an ECP. In association with microcornea ECP occurred in one case out of 2. In patients with cornea plana ECP was observed in a conspicuous form in 2 cases out of 3. ECP was absent in 2 patients with van der Hoeves’ syndrome.

In 4 cases ocular anomalies occurred in conjunction with tumours of the limbus, i. e . fibrolipoma (cases 15 and 16), fibroma (case 13) and naevus (case 14). In 2 of these cases (nos. 13 and 14) ECP was present. In 5 cases dental anomalies were associated with ocular anomalies. ECP was present in only one (no. 13) of these cases. Two of these patients (nos. 16 and 19) had facial atrophy on the left side, another (no. 13) had uveal coloboma, adhesions be- tween the limbus and the lower lid and bilateral cheilognatouranopalatoschisis. Furthermore, this patient was feeble-minded. A fourth patient (case 1 7 ) ex- hibited congenital myopia, a sphincter defect, choanal atresia and mental de- bility. In case 18 cornea plana, palatoschisis, dental anomalies, a stunted great toe (ape-foot) and syndactylia were present. This patient’s brother had the same eye and bone anomalies.

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