Journal of Clinical Ophthalmology and Research

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Year
: 2021  |  Volume : 9  |  Issue : 2  |  Page : 85--87

A rare case of acorea: Congenital absence of pupil


Parul Priyambada, Rajesh V Prabu, Rajlaxmi B Wasnik, H Ranjini 
 Department of Paediatric Ophthalmology and Strabismus, Sankara Eye Hospital, Coimbatore, Tamil Nadu, India

Correspondence Address:
Parul Priyambada
Sankara Eye Hospital, Coimbatore, Tamil Nadu
India

Abstract

Acorea is a congenital anomaly in which there is an absence of pupillary aperture. It is known to have an autosomal dominant inheritance and is associated with microphthalmos, cataract, and iridocorneal dysgenesis. It is caused when the mesodermal tissue of the iris fails to regress during embryogenesis. The lack of pupillary aperture prevents light entering the eye, often causing stimulus deprivation amblyopia. This case describes one such patient with acorea in the right eye with dense amblyopia.



How to cite this article:
Priyambada P, Prabu RV, Wasnik RB, Ranjini H. A rare case of acorea: Congenital absence of pupil.J Clin Ophthalmol Res 2021;9:85-87


How to cite this URL:
Priyambada P, Prabu RV, Wasnik RB, Ranjini H. A rare case of acorea: Congenital absence of pupil. J Clin Ophthalmol Res [serial online] 2021 [cited 2022 Aug 10 ];9:85-87
Available from: https://www.jcor.in/text.asp?2021/9/2/85/322789


Full Text



Acorea is a congenital absence of pupil which develops due to failure of regression of the mesoderm of the iris during embryogenesis. It is known to have an autosomal dominant inheritance and is associated with microphthalmia, cataract, and iridocorneal dysgenesis. The absence of pupil often causes stimulus deprivation amblyopia. A search for literature reveals five reported cases of acorea, microphthalmia, and cataract in a family[1] and two reported cases of isolated acorea as in this case.[2]

Here, we report a case of isolated acorea in a 13-year-old female with stimulus deprivation amblyopia and sensory exotropia in her right eye.

 Case Report



A 13-year-old female presented with defective vision in her right eye since her early childhood with an outward deviation of the same eye. On examination, the best-corrected visual acuity of her right eye was hand movement and left eye was 6/6 by Snellen's visual acuity chart. The right eye was deviated with poor fixation, and modified Krimsky test showed an exotropia of 45 prism diopters [Figure 1]. The extraocular movements were free and complete for both eyes. On slit-lamp examination of the right eye, the cornea was clear and normal in shape and size (12 mm horizontally and 11.5 mm vertically). The anterior chamber was quiet and appeared to be of normal depth (Van Herick's Grade 3). Iris pattern was lost, and there was an absence of pupillary aperture. Iris tissue seemed rudimentary, there was absence of crypts and collarettes, and iris surface was retracted to the center at the place of the pupil [Figure 2]. On gonioscopy of the right eye, pigmented trabecular meshwork was visible in all four quadrants showing an open angle. The lens and the posterior segment could not be visualized. The left eye findings were within normal limits. The intraocular pressure (IOP) measured 12 mmHg in both eyes. The eyes were instilled with eye drop tropicamide 0.8% and phenylephrine hydrochloride 5% three times at an interval of 10 min following which the right eye showed a slit-like opening with a white reflex [Figure 3] and the left eye showed a normal dilatation. Anterior segment optical coherence tomography (AS-OCT) was done for both eyes. AS-OCT of the right eye showed normal cornea, anterior chamber depth was normal with open angles, and there was complete absence of pupillary aperture with a continuation of iris structure throughout the iris plane [Figure 4]. AS-OCT of the left eye was normal. B-scan ultrasonography of the right eye revealed a normal lens and ruled out retinal pathology [Figure 5]. Axial length measurement of the right eye was 22.5 mm and left eye was 23 mm. As AS-OCT and B-scan showed a relatively normal structure, except the absence of pupil, it was assumed that the white reflex was due to remnant of pupillary membrane. With this, a diagnosis of isolated acorea of the right eye with stimulus deprivation dense amblyopia was made.{Figure 1}{Figure 2}{Figure 3}{Figure 4}{Figure 5}

 Discussion



Acorea is a rare congenital anomaly. It occurs due to failure of the mesodermal tissue of the iris to regress during embryogenesis at the 60 mm stage.[1] The differential diagnosis of acorea is microcoria in which the pupil diameter is <2 mm which occurs due to abnormal development of dilator muscle. In microcoria, the vision is less than normal, but dense amblyopia is rare unlike acorea.[3] To add to this, in our case, there was a complete absence of pupil before dilatation, and a slit-like pupil was seen after dilatation, which was more in favor of acorea. Furthermore, AS-OCT showed a complete absence of pupil. Persistent pupillary membrane is another congenital anomaly that occurs due to failure of mesodermal vasculature to regress, however, amblyopia is rare in such cases also.[2] In our case, we assume pupillary membrane presenting as a white reflex after dilatation. This is possible as acorea is essentially due to defective regression of mesoderm. Acorea is known to have an autosomal dominant inheritance with a possible genetic linkage to chromosomes 1, 5, 8, 11, and 17.[3] Congenital microcoria is known to occur due to mutation in chromosome 13.[4] Genetic testing would have given us a clearer picture regarding diagnosis and possible implications in future generation. However, parents did not agree to the same. There is an association of glaucoma with microcoria; hence, periodic IOP measurements become essential when microcoria cannot be ruled out. The pupil enables light stimulus to reach the retina since birth, which helps in the normal development of visual pathway. The congenital absence of pupil prevents light stimulus from reaching the retina which results in the development of amblyopia at an early age. The key to prevention of amblyopia is an early detection followed by a surgical intervention like pupilloplasty. In this case, the patient presented to us at the age of 13 years after the patient had developed significant amblyopia. At this stage, pupilloplasty would not have benefited the patient's vision. However, the patient was advised cosmetic correction for exotropia for which the patient did not comply. The patient was advised for close follow-up, and genetic counseling was done for early detection in future offsprings.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

References

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4Ramprasad VL, Sripriya S, Ronnie G, Nancarrow D, Saxena S, Hemamalini A, et al. Genetic homogeneity for inherited congenital microcoria loci in an Asian Indian pedigree. Mol Vis 2005;11:934-40.