A clinical and optical coherence tomography study of choroidal colobomas

The Vascular Pattern In Vicinity Of Chorioretinal Coloboma: An Optical Coherence Tomography Angiography Study

BACKGROUND

Chorioretinal coloboma is a congenital anomaly which can be present in a clinical spectrum with a possibility of significant influence on visual acuity. Optical coherence tomography (OCT) has been frequently used for the study of chorioretinal coloboma. OCT angiography (OCTA), as a non-invasive method of taking high-resolution images of chorioretinal vessels, can improve our understanding of developmental aspects of this anomaly.

MATERIALS AND METHODS

This observational case series evaluated patients with chorioretinal coloboma, who were referred to the eye clinic of a university-based hospital between March 2018 and October 2019. All patients underwent comprehensive ocular examination, OCT, and OCTA using AngioVue technologies from the colobomatous sites.

RESULTS

This study included OCTA imaging of five patients (six eyes) with chorioretinal coloboma lesions. Large retinal vessels, which were intact in all eyes, coursed through the coloboma in four cases and around the margin of the involved area in one case. Attenuation of the microvasculature in the vicinity of coloboma with various extents from nearly normal to severe attenuation was evident in OCTA. Five eyes of four patients had disorganized superficial vessel plexus. Also corkscrew vessels were found in one eye.

CONCLUSIONS

This is the first study assessing the vascular pattern in the vicinity of chorioretinal coloboma using OCTA. OCTA revealed nearly normal to severely attenuated retinal microvasculature. At the same time, intact large retinal vessels at the level of superficial vessel plexus coursed across or around the coloboma. OCTA imaging adds new insights about vascular characteristics in the vicinity of these lesions.

OCT Imaging in Infants

Optical coherence tomography (OCT) is widely applied in diagnosis and management of retina diseases particularly macular diseases in adult retina practices. However, it has been under-utilized in pediatric retinal diseases especially in neonates and infants. Utilization of OCT in primary macular diseases in this age group is also uncommon and is less reported. Challenges involved in image acquisition and limitations with available devices technique can explain the limited research and accurate data availability in the literature in this field. Purpose of this review article is to summarize the use of OCT and its importance in various infantile retinal pathologies such as vascular diseases, tumors, retinal dystrophies, and optic nerve pathologies with primary focus on neonates and infants, along with infant choroid. In addition, we also discuss about future directions including OCT angiography for infants.

Structure of the Retinal Margin and Presumed Mechanism of Retinal Detachment in Choroidal Coloboma

PURPOSE

To describe the vitreoretinal structure at the margin of the choroidal coloboma in infants and older patients using swept-source (SS) OCT.

DESIGN

Retrospective case series.

PARTICIPANTS

Nineteen eyes of 16 patients with choroidal coloboma (7 males, 9 females; average age, 12.3 ± 7.1 years).

METHODS

The patients were classified into 2 groups: infants 1 year of age or younger (3 eyes) and older patients (16 eyes). Each finding on SS OCT was documented according to previously defined histopathologic findings.

MAIN OUTCOME MEASURES

Description of the SS OCT features of choroidal colobomas.

RESULTS

Swept-source OCT showed that the extracolobomatous retina centrally traversed the margin to continue as the marginal intercalary membrane (MICM), whereas the outer layers of the MICM were reversed at the point (point of reversal [POR]). The expected duplication was seen in all infant eyes, but in none of the older eyes whose outer layers of the MICM were ambiguous. However, at the boundary between the layered MICM and monolayered central intercalary membrane (CICM), the POR was detectable in all patients. Further SS OCT analysis showed that the MICM schisis and CICM schisis occurred simultaneously with vitreous traction. Retinal detachments (RDs) seen in 4 eyes were connected to the only MICM schisis, and a MICM break was identified in 1 eye. Swept-source OCT showed that retinal pigment epithelial hyperplasia adhered tightly to the retina and that the glial triangle was adhered tightly to the sclera, indicating barriers to the development of RD after MICM schisis.

CONCLUSIONS

Swept-source OCT first visualized the POR in infant eyes and showed that the POR was identifiable despite the atrophic changes in the outer layer of the MICM in the older eyes. Based on the POR location, we confirmed that the intercalary membranes reported in previous OCT studies were clearly differentiated between the MICM and CICM. We also showed that the presence of MICM and CICM schisis resulted from vitreous traction at the coloboma margin and that MICM breaks induced RD only if the barrier that prevented the development of RD was broken.

Clinical Spectrum and Long-Term Anatomical and Functional Outcomes of Pars Plana Vitrectomy in Retinal Detachments Associated With Choroidal Coloboma

Purpose:

Choroidal coloboma (CC) eyes are associated with a high risk of retinal detachment (RD), which are challenging to repair.

Methods:

We retrospectively evaluated medical records of 30 patients with CC associated with RD who underwent pars plana vitrectomy at our tertiary care center. Data recorded were age, CC and RD morphology, breaks, resurgeries performed, and final outcome.

Results:

Patients’ ages ranged from 2 to 49 years. CC was present in 53 of 60 eyes (88%), with 41 of 60 eyes (68.3%) associated with iris coloboma. RD was present in 36 of 53 CC eyes (67.9%), with 10 of 53 (18.9%) having bilateral RD. Thirty-one eyes with RD underwent 23-gauge pars plana vitrectomy. Colobomatous region breaks were detected in 5 of 31 eyes (16.1%), peripheral breaks only in 12 of 31 (38.7%), and both types in 3 of 31 eyes (9.7%). Silicone oil endotamponade was used in 29 of 31 eyes (93.5%) and perfluoropropane (C3F8) in 2 of 31 eyes (6.45%). Median postoperative follow-up duration was 31.5 months. Fourteen of 31 eyes (45.2%) developed redetachment requiring resurgery, with 50% developing within 6 months. Eighteen of 31 eyes (58.1%) maintained retinal attachment at last follow-up without endotamponade, whereas the rest were oil filled. Final visual outcome between macula-involved and macula-spared CC eyes was not significantly different; however, best visual acuity achieved any time during follow-up was significantly better in macula-spared eyes.

Conclusions:

RD surgery in CC eyes has a risk of frequent redetachments and subnormal gain of vision over the long term, especially in colobomas involving the macula. Endolaser in 360° peripheries in addition to barrage of the margin of the coloboma may be considered to help maintain the attached retina.

Swept-Source OCT Analysis of the Margin of Choroidal Coloboma: New Insights

PURPOSE

To study the retinal architecture and vitreoretinal interface at the edge of choroidal coloboma using swept-source OCT.

DESIGN

Prospective observational case series at a tertiary eye care center.

PARTICIPANTS

Patients with choroidal coloboma treated at an ophthalmology department and fulfilling the inclusion criteria of the study.

METHODS

Swept-source OCT was carried out in 30 eyes of 20 patients with choroidal coloboma.

MAIN OUTCOME MEASURES

The primary objective was to describe the OCT features at the margin of the coloboma.

RESULTS

Swept-source OCT of the coloboma margin revealed new features in addition to the previously described findings. Two types of transition from normal retina into intercalary membrane (ICM) were noted: abrupt (73.33%) and gradual (26.67%). Outer retinal layers (interdigitation zone and ellipsoid zone) terminated at a variable distance before the retinal pigment epithelium in 56.67% of eyes. Cystic spaces in the ICM (46.67%), schisis-like spitting of the ICM (30%), and breaks in the ICM (6.67%) were seen as well. Subclinical retinal detachment (RD) was also noted in 1 eye. The peculiar features noted at the vitreoretinal interface included vitreous attachment at the coloboma margin (23.33%), vitreous condensation (6.67%), and hill like projections of ICM into the vitreous cavity (26.67%). In the region of the coloboma, sclera and Tenon's capsule could also be analyzed as a hyperreflective lamellar structure and an irregularly arranged less hyperreflective structure.

CONCLUSIONS

Swept-source OCT of the coloboma margin revealed various new features in addition to those described previously. The detection of subclinical RD or early termination of outer retinal layers in selected cases may be helpful in guiding new management protocols.

Retinal detachments in the pediatric population

In this review, we present a concise summary of the more commonly seen types of retinal detachments (RDs) that one can encounter in pediatric patients. A spectrum of diseases from rhegmatogenous RD in Stickler syndrome, Marfan syndrome, and choroidal coloboma to exudative RD in Coats disease, to tractional RD in persistent fetal vasculature, and combined RDs in familial exudative vitreoretinopathy are described with the management pearls for each.

Intercalary membrane as the inner wall overlying optic and chorio-retinal colobomas. Deep penetration Swept Source-OCT study

Five eyes of four patients were studied to analyze the structure of the inner wall of optic and chorioretinal colobomas using swept-source optical coherence tomography (SS-OCT). The colobomatous cavities and their relationship with adjacent structures were examined. SS-OCT permitted the study of the colobomatous cavities in all cases. In four of those cases, a Y-shaped intercalary membrane (ICM) was identified, with an origin in the retinal nerve fiber layer (RNFL), which covered the coloboma and in one case the coloboma was in contact with the vitreous cavity. Vitreous adhesion to the internal wall of the coloboma was found in three cases. No clinical or tomographic maculopathy was observed in any patient. High-resolution deep penetration SS-OCT allows in vivo study of optic and chorioretinal colobomas, identifying the RNFL as the main component of the ICM overlying the colobomatous cavities.

Ultrasonographic evaluation of transition from normal to ectatic area: A comparison between myopic staphylomata and coloboma

Choroidal coloboma and posterior staphyloma are two clinically distinct entities, with choroidal excavation being a unifying feature. They are associated with early onset cataract which can make ophthalmoscopy difficult. This report studies the transition between the normal and ectatic area in these cases with ultrasound. We evaluate “posterior hump” as a sign of differentiation between these two conditions.

Aborted choroidal coloboma: fundus imaging and optical coherence tomography

Choroidal coloboma is characterised by poor embryonic development of chorioretinal structures and is of different types. We present a case of choroidal coloboma where the retinal pigment epithelium was present, clinically and on imaging, but rest of the structures were poorly formed. This observation suggests that in some cases, fusion of the fetal cleft may occur aberrantly, resulting in an aborted choroidal coloboma.

Chorioretinal Coloboma in a Patient with Pancreas Divisum: Clinical and Imaging Features

Purpose

To report the case of a 61-year-old woman with pancreas divisum and an asymptomatic chorioretinal coloboma in its 2 forms: complete and partial.

Methods

Case report.

Results

Dilated fundus examination and photograph revealed a complete and partial coloboma in the right eye. Swept-source optical coherence tomography and swept-source optical coherence tomography angiography (SS-OCTA) were performed. Swept-source optical coherence tomography angiography disclosed the complete coloboma as a black, round, avascular area surrounded by normal vascular tissue in every plexus (i.e., superficial, deep, and choriocapillary). Although irregular and attenuated, the vascular network of the partial coloboma was appreciable in each layer, indicating some degree of vascular preservation.

Conclusions

Chorioretinal coloboma has been linked to several ocular and systemic conditions. To our knowledge, no association between coloboma and pancreas divisum has been reported. In addition, chorioretinal coloboma has not been previously characterized by means of SS-OCTA.

Vitrectomy treatment of retinal detachments related to choroidal coloboma involving the disk

PURPOSE

To evaluate the anatomical and functional outcomes of retinal detachment with choroidal coloboma involving the disk, by incising the entire intercalary membrane along the margin of the coloboma and displacing part of the macular retina to healthy retinal pigment epithelium (RPE), and then treating the entire margin of the RPE surrounding the coloboma with diode laser.

METHODS

Pars plana vitrectomy was performed in five eyes with retinal detachment resulting from choroidal coloboma involving the disk. The entire intercalary membrane along the margin of the coloboma was incised. Part of the intercalary membrane in the macular region remained, and together with the macular retina was displaced slightly to healthy RPE. Carefully titrated diode laser burns were applied in the functional border of the disk (the border of papillomacular bundle) to reduce the nerve fiber layer damage, and endolaser of three to four rows was performed along the border of the coloboma. Anatomical reattachment of the retina and visual acuity were measured.

RESULTS

At the end of 12 months after the first surgery, the rate of retinal reattachment was 100% (5 eyes), and visual acuity improved from a preoperative perception of light or hand movement to counting fingers in 2 eyes and 3 eyes retained preoperative visual acuity.

CONCLUSION

For these retinal detachment eyes with choroidal coloboma involving the disk, complete vitrectomy, incising the entire intercalary membrane along the margin of the coloboma and displacing part of the macular retina to healthy RPE, treating the entire margin of the RPE surrounding the coloboma with diode laser provides an effective treatment for this complicated type of retinal detachment with good long-term anatomical outcome.