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Combination of congenital optic never coloboma in one eye and congenital choroidal coloboma in the fellow eye
- Authors: Simakova I.L.1, Kirillov Y.A.1, Sosnovskiy S.V.1, Tikhonovskay I.A.1, Kharakozov A.S.2, Nikolaenko E.N.1
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Affiliations:
- S.M. Kirov Military Medical Academy
- Military Hospital
- Issue: Vol 10, No 3 (2017)
- Pages: 85-90
- Section: Articles
- URL: https://journals.eco-vector.com/ov/article/view/7199
- DOI: https://doi.org/10.17816/OV10385-90
- ID: 7199
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Abstract
The article presents an interesting and fairly rare clinical case of congenital posterior segment anomaly of both eyes manifesting itself by coloboma of the optic nerve head in the right eye and choroidal coloboma in the left eye. For the first time, this pathology was diagnosed in our female patient at the age of 48.
Full Text
We present a rare combination of congenital anomalies in the posterior segments of both eyes in a 48-year-old female. The patient had optic disk (OD) coloboma in the right eye and choroidal coloboma in the left eye.
The patient had previously been examined by ophthalmologists at various medical institutions. Because she had no complaints, ophthalmoscopy with dilated pupil was not performed. Stage II hypertension was the only existing comorbidity in the patient.
OD coloboma was first described by de Wecker in 1886 [6]. This congenital disorder follows an autosomal dominant pattern of transmission with reduced penetrance. It may also occur sporadically between the third and tenth week of gestation during which the development of the optic nerve fibers occurs; this disorder arises because of incomplete closure of the embryonic fissure [2]. The prevalence of various congenital colobomas of the tunics and other structures of the eyeball is 0.5–0.7 per 10,000 newborns; among these, more than 60% have iris coloboma. However, we were unable to find data on the prevalence of congenital OD coloboma.
Upon examination, the patient was found to have a visual acuity of 1.0, an emmetropic refraction, and an intraocular pressure of 20–21 mmHg (according to Maklakov). Ophthalmoscopy with pharmacologic mydriasis revealed an increase in OD diameters in both eyes. OD of the right eye was almost twice as big as that of the left eye and had a white deepening with rounded contours similar to severe glaucomatous excavation (cup/disk ratio of 0.8–0.9) (Figure 1). In the left eye, the cup/disk ratio was 0.5–0.6. A choroidal defect of 2 × 2.5 pupil diameter (PD) was detected at a distance of 0.5 PD from the lower OD border, and a deepening in the sclera was detected in its projection (Figure 2). The anteroposterior axis of the right and left eyeballs [measured using an IOLMaster (Carl Zeiss, USA)] was 23.89 mm (with 24.9 mm deepening in OD) and 23.87 mm (with 25.5 mm deepening in the sclera), respectively. Ultrasonic B-scanning using AVISO (Quantel Medical System, France) confirmed a scleral protrusion in the projection of the choroidal defect in the left eye.
Fig. 1. Ophthalmoscopic picture of patient K.’s right ONH coloboma
Fig. 2. Ophthalmoscopic picture of patient K.’s left ONH and choroidal coloboma
The patient underwent additional eye examinations to determine the severity of structural and functional changes and exclude the diagnosis of pseudonormal pressure open-angle glaucoma (PNP OAG).
We performed standard and nonstandard perimetry. Kinetic visual field perimetry (using the Goldmann perimeter) showed 10° narrowing of the peripheral visual field (from the outside and from the top) in the right eye, normal peripheral visual field in the left eye, and 20° × 30° relative scotoma located in the lower nasal quadrant of the left eye, which corresponds to choroidal coloboma. Humphrey automated perimetry (HAP) using the Humphrey 745i Visual Field Analyzer II (Germany/USA, program 24–2) demonstrated severe depression of light sensitivity in the upper half of the central visual field (CVF), reaching the fixation point and involving the blind spot area of the right eye. A slight depression of light sensitivity was observed in the left eye because of expansion of the blind spot area; the mean deviation index was –17.74 and –3.51 dB in the right and left eyes, respectively (Figure 3). The visual field loss was also assessed using frequency-doubling technology (FDT) perimetry modified by Simakova et al. [4]. The FDT perimetry findings correlated with the HAP results.
Fig. 3. Patient K.’s SAP (Humphrey) results, both eyes
The patient also underwent confocal laser scanning tomography using the Heidelberg retinа tomograph (HRT) (Germany) and optical coherence tomography (OCT) using the Topcon 3D OCT-2000 System (Japan), which confirmed the presence of macrodisks in both eyes and pronounced asymmetry in their size. Upon HRT examination, the areas of the right and left ODs were 5.5 and 3.64 mm2, respectively. OCT showed that the areas of the right and left ODs were 5.84 and 3.21 mm2, respectively. The cup/disk ratios for the right and left eyes were 0.81 and 0.54, respectively. A large tissue defect spreading into the optic nerve was detected on OCT of the right eye. No lattice membrane was visualized in the area of the defect, indicating that it was probably absent. The mean thickness of the retinal nerve fiber layer in the inferotemporal area of OD was found to be reduced (Figure 4).
Fig. 4. OCT data. Patient K.’s right eye ONH coloboma and ONH parameters
OCT of the right OD (Figure 4) seemed to indicate glaucomatous excavation (typical of severe glaucoma); however, as shown in Figure 5, the lattice membrane in a patient with stage III OAG is preserved throughout its entire length. OCT of the left eye revealed that the retinal nerve fiber layer thickness was within the normal limits. Under OD, we detected a deepening in the sclera with significant thinning of the neurosensory retina, no pigment epithelium, and no choroid above it, which corresponded to choroidal coloboma and scleral staphyloma in its projection.
Fig. 5. OCT data. Patient G.’s left eye ONH cupping and other parameters in advanced OAG
The evaluation of structural and anatomical characteristics of the posterior segments of both eyes revealed a deepening in OD of the right eye, which could be considered as OD coloboma, glaucomatous excavation, or a combination of both, and choroidal coloboma with scleral staphyloma in its projection in the left eye.
The results of standard and nonstandard computer-assisted threshold perimetry suggested a severe depression of light sensitivity in the upper half of CVF of the right eye and a slight depression of light sensitivity in the left eye due to an expansion of the blind spot area.
We also performed the following electrophysiological examinations (EPEs) of both eyes to evaluate the bioelectric activity of optical neurons in accordance with the standards of the International Society for Clinical Electrophysiology of Vision: general electroretinography (GERG), rhythmic electroretinography (RERG) (30 Hz), and assessment of visually evoked cortical potentials (VECPs) produced by exposing the eye to a rapidly reversing checkerboard pattern [7, 8]. All EPEs were conducted using the Tomey EP-1000 Multifocal System (Tomey Corporation, Japan). The results of GERG and RERG revealed no abnormalities in the retinal electrogenesis of both eyes (neither in the photoreceptors and bipolar cells nor in the retinal cones). Analysis of VECPs revealed signs of impaired functional activity of the visual pathways in the right eye, including a 3 μV (56%) decrease in the peak N80 amplitude, and an increase in its latency by 16.5 ms (21.6%) compared with normal parameters in the left eye. Our findings correlate with those of other studies involved in exploring electrophysiological parameters of the eye in patients with similar disorders [3, 9]. The absence of pathological changes on GERG and RERG of the right eye suggest a normal anatomical condition of its external retinal layers. The absence of pathological changes on GERG and RERG of the left eye with choroidal coloboma can be explained by the relatively small size of the coloboma (<2.5 PD), which limits its impact on electrogenesis in the external retinal layers.
The detected interocular difference in VECPs matches the results of other structural, anatomical, and functional examinations, confirming the fundamental principle of correlation between structure and function.
After the examinations, the patient was concluded to have optic neuropathy of the right eye. To exclude PNP OAG, we performed a well-known Volkov–Sukhinina–Ter-Andriasov load vacuum-perimeter test and a modified version of this test based on FDT perimetry [1, 5]. The results of these load tests were negative for both eyes.
Several findings led us toward the conclusion that optic neuropathy of the right eye was not caused by glaucomatous process but was a manifestation of congenital OD coloboma. These findings included the following: specific excavation (non-typical of glaucoma) with a nerve tissue defect and no lattice membrane in this area; reduced thickness of the retinal nerve fiber layer in a limited area (lower external); central location of the vascular bundle; normal intraocular pressure; negative results of load tests; and, most importantly, stable visual function for many years.
In our opinion, this case is particularly interesting because the patient was first diagnosed with a congenital ocular disorder at the age of 48 years. The reason for late diagnosis is probably the patient’s high visual acuity and absence of overt symptoms; thus, ophthalmoscopy was performed on non-dilated pupils and without a detailed examination of the ocular fundus.
Despite the hereditary nature of the disease and the stability of visual function, such patients should be regularly examined by an ophthalmologist. Existing visual field changes (primarily in the right eye) creates an unfavorable background that may hamper the diagnosis of other ocular diseases, including glaucoma, neuritis, and impaired blood supply of OD and retina, and brain diseases. Differential diagnosis of these disorders requires comprehensive examination using various methods, including computed tomography of the retina, standard and nonstandard computer-assisted threshold perimetry, electrophysiological examinations, and load tests.
The patient has been followed up since December 2015.
About the authors
Irina L. Simakova
S.M. Kirov Military Medical Academy
Author for correspondence.
Email: irina.l.simakova@gmail.com
Med.Sc.D., Associate professor. Ophthalmology Department
Russian Federation, Saint PetersburgYuriy A. Kirillov
S.M. Kirov Military Medical Academy
Email: irina.l.simakova@gmail.com
PhD, Associate professor. Ophthalmology Department
Russian Federation, Saint PetersburgSergey V. Sosnovskiy
S.M. Kirov Military Medical Academy
Email: svsosnovsky@mail.ru
PhD, Associate professor. Ophthalmology Department
Russian Federation, Saint PetersburgIrina A. Tikhonovskay
S.M. Kirov Military Medical Academy
Email: irenpetrova@yandex.ru
MD, Ophthalmology Department
Russian Federation, Saint PetersburgAleksandr S. Kharakozov
Military Hospital
Email: Kharakozoff@mail.ru
MD, senior physitian
Russian Federation, PskovEvgenia N. Nikolaenko
S.M. Kirov Military Medical Academy
Email: e.n.nikolaenko@mail.ru
MD, Ophthalmology Department
Russian Federation, Saint PetersburgReferences
- Волков В.В., Сухинина Л.Б., Устинова Е.И. Глаукома, преглаукома, офтальмогипертензия. – Л.: Медицина, 1985. – 216 с. [Volkov VV, Sukhinina LB, Ustinova YeI. Glaucoma, preglaucoma, ophthalmohypertension. Leningrad: Meditsina; 1985. 213 p. (In Russ.)]
- Горбачев Д.С., Коровенков Р.И. Врожденный микрофтальм с кистой // Офтальмологические ведомости. – 2015. – Т. 8. – № 1. – C. 61–68. [Gorbachev DS, Korovenkov RI. Сongenital microphtalmos with cyst. Ophthalmology journal. 2015;8(1):61-68. (In Russ.)]. doi: 10.17816/OV2015161-68.
- Мосин И.М. Аномалии экскавации зрительного нерва: клинические проявления и дифференциальная диагностика // Вестник офтальмологии. – 1999. – Т. 115. – № 5. – C. 10–14. [Mosin IM. Anomalies of optic nerve excavation: the clinical manifestations and differential diagnosis. Vestn Oftalmol. 1999;115(5):10-14. (In Russ.)]
- Симакова И.Л., Волков В.В., Бойко Э.В., и др. Создание метода периметрии с удвоенной пространственной частотой за рубежом и в России // Глаукома. – 2009. – Т. 8. – № 2. – С. 15–21. [Simakova IL, Volkov VV, Boiko EV, et al. Creation of the method of frequency-doubling technology perimetry: an international and Russian experience. Glaucoma. 2009;8(2):15-21. (In Russ.)]
- Симакова И.Л., Сухинин М.В., Тихоновская И.А., и др. Новая нагрузочная проба для выявления и мониторинга глаукомы // Новости глаукомы. – 2017. – № 1. – С. 78–82. [Simakova IL, Sukhinin MV, Tikhonovskay IA, et al. New stress test for the detection and monitoring of glaucoma. News glaucoma. 2017;(1):78-82. (In Russ.)]
- De Wecker. Le faux glaucoma. Ann d’Oculistiqune. 1896;116:249-262.
- McCulloch DL, Marmor MF, Brigell MG, et al. ISCEV Standard for full-field clinical electroretinography: [2015 update]. Doc Ophthalmol. 2015;130:1. Available at: https://link.springer.com/article/10.1007/s10633-014-9473-7.
- Odom JV, Bach M, Brigell MG, et al. ISCEV Standard for clinical visual evoked potentials: [2016 update]. Doc Ophthalmol. 2016;130:1. Available at: https://link.springer.com/article/10.1007/s10633-016-9553-y.
- Tormene AP, Riva C. Electroretinogram and visual-evoked potentials in children with optic nerve coloboma. Doc Ophthalmol. 1998;96(4):347-354. doi: 10.1023/a:1001720210698.
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