Table of Contents  
CASE REPORT
Year : 2020  |  Volume : 28  |  Issue : 1  |  Page : 42-45

Retinochoroidal Coloboma in a Female Nigerian


Department of Ophthalmology, College of Medicine, University of Ibadan, Ibadan; Department of Ophthalmology, University College Hospital, Ibadan, Nigeria

Date of Submission22-Jun-2019
Date of Decision22-Feb-2020
Date of Acceptance12-Mar-2020
Date of Web Publication07-Sep-2020

Correspondence Address:
Yewande Olubunmi Babalola
Department of Ophthalmology, University College Hospital, Ibadan
Nigeria
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/njo.njo_13_19

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  Abstract 


We report a case of retinochoroidal coloboma in a 32 year old Nigerian female who first presented to the eye outreach clinic with a history of poor vision in the left eye of two years duration. The best corrected visual acuity was 6/5 and light perception with accurate light projection in the right and left eyes respectively. She was subsequently referred to the retina clinic for Neodymium:yttrium- aluminium- garnet (Nd:YAG) laser capsulotomy on account of a left posterior capsular opacity after cataract surgery at the eye outreach clinic with a best corrected visual acuity of 6/5 and 6/36 respectively in the right and left eye. Dilated binocular indirect ophthalmoscopy of the left eye revealed a large, wedge-shaped, excavated retinochoroidal defect with hyperpigmented edges involving the nasal retina extending across approximately five clock hours from 7 to 10 o’clock. The apex of the coloboma was approximately three disc diameters away from the optic nerve head and extended peripherally up to the ora serrata. The right fundus was normal. Retinochoroidal colobomas may occur in the absence of the known blinding sequelae like retinal detachment, choroidal neovascular membrane amongst others. Our patient had a cataract in the same eye with the retinochoroidal coloboma with subsequent visual gain post-surgery and increasing myopia.

Keywords: Female Nigerian, increasing myopia, pseudophakia, retinochoroidal coloboma


How to cite this article:
Babalola YO, Oluleye TS. Retinochoroidal Coloboma in a Female Nigerian. Niger J Ophthalmol 2020;28:42-5

How to cite this URL:
Babalola YO, Oluleye TS. Retinochoroidal Coloboma in a Female Nigerian. Niger J Ophthalmol [serial online] 2020 [cited 2022 Aug 8];28:42-5. Available from: http://www.nigerianjournalofophthalmology.com/text.asp?2020/28/1/42/294378




  Introduction Top


Retinochoroidal colobomas are ocular colobomata which occur due to a failure of closure of the fetal or choroidal fissure during embryogenesis.[1] They usually occur during the 5th to 7th week of life.[2] Incidence of ocular colobomas vary from 0.5 to 2.2 cases per 10000 live births. Retinochoroidal colobomas, though not as common as other ocular colobomata are said to have an incidence of about 0.14%.[3]

Retinochoroidal colobomas may coexist with colobomas of the iris, zonules, ciliary body, optic nerve and other ocular structures.[4] Ocular pathology like cataract and microphthalmia may be seen in association with retinochoroidal colobomas.[4],[5] Visual impairment in retinochoroidal coloboma is usually dependent on the extent, location, depth of excavation of the lesion and involvement of the optic nerve and macula.[6],[7]

To the best of our knowledge, this is the first case of retinochoroidal coloboma reported in Nigeria though cases of optic disc coloboma occurring in two Nigerian siblings have been earlier documented.[8] Three cases of uveal coloboma with two being retinochoroidal coloboma have been reported in Yaounde, Cameroon.[9] Retinochoroidal colobomas may be missed in the presence of cataracts hence, post-operative binocular indirect ophthalmoscopy is essential in diagnosis.


  Case Report Top


A 32 year old business woman, an old patient of our eye outreach clinic presented to the retina clinic with a complaint of poor vision in the left eye of two years duration. She had been seen previously at the eye outreach clinic seven years ago with a similar complaint. There was no antecedent history of trauma, recurrent redness, pain nor photophobia. From her old patient notes, visual acuity at presentation was light perception with accurate light projection; the right eye was essentially normal with a visual acuity of 6/5. An assessment of a left presenile cataract had been made then for which she subsequently had an uneventful left cataract surgery with insertion of a posterior chamber intraocular lens. The best corrected visual acuity in the operated left eye was 6/9 with a myopic correction of −0.50DS six months post-operative. She was then lost to follow-up and represented to the eye outreach clinic five years post-operatively requesting for a new pair of spectacles. The refraction in the left eye was −3.50DS −1.75DC x 50 with a visual acuity of 6/6 and plano in the right eye; an increase in the myopic component of the subjective refraction was noted. She was referred from the eye outreach clinic to the retina clinic to have a dilated binocular indirect ophthalmoscopy for retina evaluation on account of the increasing myopia to rule out degenerative myopic changes but defaulted and was lost to follow-up.

At this current presentation two years after her last follow-up visit, she gave a history of deterioration of vision in the left eye. Ocular examination at this presentation revealed a visual acuity of 6/5 and 6/36 in the right and left eyes respectively. The left eye was pseudophakic with a dense posterior capsular opacity extending over the pupillary axis and inferior capsule. The right anterior segment was within normal limits. The intraocular pressures were 14 and 15 mmHg respectively in the right and left eye. Her best corrected visual acuity with refraction was 6/5 in the right eye with a correction of pl − 0.50DC x 75 and 6/24 in the left with −5.00DS.

Right dilated binocular indirect ophthalmoscopy revealed cup disc ratio of 0.3, pink disc with distinct margins, normal vessels and macula with flat retina and no retinal lesions as seen in [Figure 1]A; indirect ophthalmoscopy on the left revealed a pink disc with cup disc ratio of 0.3 with distinct margins, peripapillary degeneration, normal vessels and early pigmentary changes at the macula and a vitreous opacity. Nasally, there was a large wedge- shaped hypopigmented defect with a surrounding brownish hyperpigmented border with scleral exposure at the base about three disc diameters from the optic disc extending from about 7 o’clock to 10.30 o’ clock [Figure 1]B and [Figure 2]. White without pressure was also seen at the periphery of the left eye otherwise the retina was flat with no holes nor tears seen.
Figure 1 (A) Shows the right fundus picture taken with a handheld fundus camera with a pink disc, CDR 0.3, normal macula & vessels with flat retina while. (B) Shows the left fundus with a pink disc and the wedge-shaped retinochoroidal coloboma in the nasal quadrant

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Figure 2 Shows the left retinochoroidal coloboma distinctly as a wedge-shaped defect with excavation and visible underlying sclera with raised edges outlined by choroidal pigmentation

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There was no history of systemic nor concurrent medical illnesses. General and systemic examination of the central nervous, cardiovascular, respiratory systems and the abdomen was essentially normal.

A diagnosis of a left nasal retinochoroidal coloboma in a pseudophakic eye with posterior capsular opacity and uniocular myopia with anisometropia was made. She subsequently had a left uneventful Neodymium:yttrium-aluminium- garnet (Nd:YAG) capsulotomy. A good gap was made centrally and she was commenced on guttae dexamethasone four times daily for a week.

On her follow-up visit post-capsulotomy, unaided visual acuity was 6/5 and 6/18 respectively in the right and left eyes. The left eye improved to 6/6-2 with correction of −5.00DS-0.50DC x 170. Binocular indirect ophthalmoscopy findings were essentially the same as at the last visit with no indication for barrage laser. She was scheduled for bi-yearly follow-up visits if there was no significant acute ocular complaint. Our patient was counselled on the need for regular, dilated ophthalmic examinations and the need for prompt presentation if symptoms like flashes of light, floaters, field defects or deterioration in vision occurs.


  Discussion Top


Retinochoroidal coloboma appear as a hypopigmented defect revealing an area of bare sclera with the overlying RPE, retina, or choroid absent. In some cases, the retina though present may be hypoplastic and gliotic.[10] Colobomas typically occur more commonly in the inferonasal quadrant as seen in our index patient.

Retinal detachment and cataracts are the most common complication and aetiology of visual impairment in patients with choroidal colobomas.[11] Rhegmatogenous retinal detachments occur in about 4–40% of cases and is due to breaks within or adjacent to the coloboma.[10],[12] Non-rhegmatogenous retinal detachments may also be associated with retinochoroidal colobomas especially those coexisting with colobomas of the optic disc particularly the autosomal dominant variant.[13] Retinal detachment or retinal breaks was not present in our patient.

Cataracts of various morphology may occur with ocular colobomas with nuclear sclerosis being the most common. Distinct linear opacity in the region of the coloboma have been described as coloboma cataract. Lens subluxation may also be present. Our patient had total opacification of the lens in the eye with the retinochoroidal coloboma.[14]

Choroidal neovascular membranes though rare, occur in patients with retinochorioroidal colobomas. The choroidal neovascularisation occurs due to pre-existing anomalies at the margin where the retinal pigment epithelium is folded and thickened, retina is atrophic and the barrier function of Bruch’s membrane is disrupted hence it is postulated that this anomalous retinal tissue serves as an entry site for growth of abnormal blood vessels.[12],[15] This neovascular membrane usually develops at the superotemporal edge and is similar to the variety seen in high myopia, angiod streaks, choroidal rupture and choroiditis.[16] Colobomatous eyes are frequently myopic and have vitreous syneresis, which increases vitreous traction.[10],[17] Our index patient had myopia which was progressively increasing but with no breaks in bruchs’ membrane and no significant vitreous syneresis.[10]

Our patient is closely followed up for prophylactic laser barrage if indicated. In a study carried out in a paediatric population in India, it was discovered that eyes in which prophylactic laser was not applied at the edge of the retinochoroidal colobomas were 8.755 times more likely to develop rhegmatogenous retinal detachment in comparison to eyes that received prophylactic laser at the edge of the retinochoroidal coloboma.[18]

Meckel syndrome is a syndromic association of retinochoroidal coloboma in which ocular disorders like secondary glaucoma with related angle abnormalities, amblyopia and anisometropia and sensory strabismus may be present.[17] Anisometropia was present in our patient. Systemic disorders which may be sporadic or inherited like the CHARGE syndrome may also present with ocular colobomas.[5],[14] It has been documented in literature that bilateral large retinal colobomas are a feature of the CHARGE syndrome occurring in up to 70% of these patients.[19]The Ida-Mann classification groups retinochoroidal colobomas into seven types depending on location and closeness to the disc. In the type 1, the coloboma extends above the anatomic disc while type 2 colobomas extending up to the superior border of the disc. Colobomas extending below the lower border of disc are classified as type 3 and those involving only the disc are type 4 colobomas. Coloboma present below the disc with normal retina above and below the coloboma are classified as type 5. Pigmentation present in the periphery is classified as type 6 while colobomas involving only the periphery are the type 7.[20] The retinochoroidal coloboma in our index patient falls into the type 7 category located in the peripheral nasal retina in the left eye.

Possible differential diagnoses for the retinochoroidal coloboma include chorioretinal scar, staphyloma and congenital hypertrophy of the retinal pigment epithelium though retinochoroidal colobomas are usually lesions with characteristic features which can be clearly differentiated from these other retinal conditions.


  Conclusion Top


Isolated retinochoroidal colobomas may be obscured by co-existing presenile uniocular cataract as seen in this patient. Detailed retinal examination is a mainstay in diagnosing these cases. Prophylactic laser may be applied where indicated while prompt treatment with pars plana vitrectomy may be beneficial in treating retinal detachments occurring from these colobomas.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

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9.
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Mohammed A, Chaurasia S, Ramappa M, Sangwan VS, Jalali S. Lenticular changes in congenital iridolenticular choroidal coloboma. Am J Ophthalmol 2014;158:827-30  Back to cited text no. 14
    
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Rouland JF, Hochart G, Constantinides G. Chorioretinal coloboma and neovascular membrane. Bull Soc Ophthalmol Fr 1990;90:643-4.  Back to cited text no. 16
    
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MacRae DW, Howard RO, Albert DM, Hsia YE. Ocular manifestations of the Meckel syndrome. Arch Ophthalmol 1972;88:106-13.  Back to cited text no. 17
    
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Uhumwangho OM, Jalali S: Chorioretinal coloboma in a paediatric population. Eye 2014;728-33.  Back to cited text no. 18
    
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Hatsukawaa Y, Kansawa K, Yamane T, Mizuno S, Tsuzuki K, Kosaki K. Ophthalmic features of CHARGE syndrome with CHD 7 mutation. Am Jmed Genetic A 2012;158A:514-8.  Back to cited text no. 19
    
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Mann I. Developmental Abnormalities of the Eye. Cambridge University Press: London, 1937; 65-103.  Back to cited text no. 20
    


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