|Year : 2008 | Volume
| Issue : 1 | Page : 67-68
Single lens to lens duplication: The missing link
Rupal Bhatt1, Jitendra Jethani2, Praveen Saluja3, Vinay Bharti1
1 Cornea Unit, M and J Regional Institute of Ophthalmology, Ahmedabad- 380 016, India
2 Pediatric Ophthalmology and Strabismus Clinic, M and J Regional Institute of Ophthalmology, Ahmedabad- 380 016, India
3 M and J Regional Institute of Ophthalmology, Ahmedabad - 380 016, India
|Date of Web Publication||21-Dec-2007|
Pediatric Ophthalmology and Strabismus Clinic, M and J Regional Institute of Ophthalmology, Civil Hospital, Ahmedabad - 380 016
Source of Support: None, Conflict of Interest: None
Congenital anomalies of the lens include a wide range from lens coloboma to primary aphakia and doubling of lens. There have been few case reports of double lens; the etiology suggested is metaplastic changes in the surface ectoderm that leads to formation of two lens vesicles and hence resulting in double lens. We report a case with bilobed lens, which raises the possibility of explaining the etiology of double lens.
Keywords: Bilobed lens, lens coloboma, lens duplication
|How to cite this article:|
Bhatt R, Jethani J, Saluja P, Bharti V. Single lens to lens duplication: The missing link. Indian J Ophthalmol 2008;56:67-8
|How to cite this URL:|
Bhatt R, Jethani J, Saluja P, Bharti V. Single lens to lens duplication: The missing link. Indian J Ophthalmol [serial online] 2008 [cited 2020 Jul 16];56:67-8. Available from: http://www.ijo.in/text.asp?2008/56/1/67/37601
Congenital coloboma of the lens is the most common congenital anomaly of lens. In the region of the coloboma, there is usually some defect in the zonules and hence the resultant coloboma. Cases with duplicated lens that is a single eye carrying two lenses, have been described. ,, The exact mechanism for this anomaly is not known yet. Our case serves to explain the connection between lens coloboma and duplicated lens.
| Case History|| |
A young boy, 16 years old, presented with complaints of poor vision in the left eye since childhood. There was no history of any treatment or surgical intervention. In addition, no history pertaining to any trauma was given. Birth history was not significant. On examination, he had a vision of 20/200 in the right eye (RE) and 20/20 in the left eye (LE). The LE was clinically normal with a normal fundus. The RE revealed a horizontally placed bilobed lens sharing a common capsular bag. Zonules were lacking around the fissure between the two lobes [Figure - 1]. Also, there was an inferior iris coloboma. Fundus was normal in both eyes. An ultrasonogram of the right eye [Figure - 2] revealed a bilobed lens in the anterior segment of the eye with normal posterior segment.
| Discussion|| |
Congenital anomalies of the lens are varied. Partial congenital aphakia is a rare condition in which the lens appears to be partially divided by a deep furrow.
In the case of congenital duplication of lens reported by Thakkar et al. two lenses were placed obliquely in a straight line with a clear area in between. Absence of zonules and capsule between the two lenses was also noted. Richardson reported a case in which the two lenses were asymmetrical, one being larger than the other. The patient also had corneal metaplasia, complete coloboma of iris and fundus.
The mechanism for this anomaly is not known yet. Whether it is part of a phylentogenic spectra or represents development from two embryonically separate lens remains a question. Duke Elder has tried to explain the occurrence of the two entities based on separate embryonic developmental sequences. He suggested that the metaplastic changes in the surface ectoderm leads the lens plate to invaginate at two place and forms two lens vesicles which results in double lens. This suggests that the lens is divided before the lens starts developing.
Our case has a deep furrow in the center [Figure - 1] with localized absence of zonules. We, therefore, suggest that once the deep furrow is formed due to absence of zonules, it may go further (deep) enough to divide the lens into two distinct parts. Therefore, the absence of zonules is significant and these furrows may be deep enough and progress to duplication. It is a possibility that the lens duplication might be occurring when the lens vesicle is single and it is the laxity and abnormal stretching which causes the deep furrow and possibly duplication. Duplication may be the extreme form of such a bilobed, furrowed lens. It is interesting to note that both the cases previously reported- had lens place in a straight axis at opposite ends. This gives further credence to our theory of the fissure dividing the lens into two and the remaining zonules pulling them away from each other.
Since lens coloboma occurs frequently such deep furrows (bilobed lens) are uncommon. We believe that it represents the missing link between the colobomatous lens and duplicated lens. We understand that a single case report may not be suggestive of any mechanism but nevertheless it does indicate a possible mechanism of lens duplication.
| References|| |
Elder D. Anomalies of lens. In: System of ophthalmology. Henry Kempton; 1969. p. 688-741.
Thakkar H, Singh R. Congenital double crystalline lens. J Cataract Refract Surg 2003;29:405-6.
Richardson O. Congenital anomalies of the anterior segment. Trans Can Ophthalmol Soc 1951;14:102-3.
[Figure - 1], [Figure - 2]