Congenital Anomalies: Simultaneous presentation of two distinct conditions in one patient

Sarah E. Kochik Pediatrics and Primary Care Resident University of California, Berkeley School of Optometry

Abstract

A review of congenital optic nerve anomalies through the management of a patient who presents with an optic nerve and retinal coloboma in one eye and a congenital pit in the fellow eye.

I. Case History a. Patient demographics: 7 year old Caucasian female, 1st grade b. Chief complaint: failed school vision screening c. Ocular, medical history: seen by an O.D. 1 year prior, glasses were not recommended d. Medications: none e. Other salient information Born on time, no birth complications, on target for reaching developmental milestones, no remarkable health history or significant family history II. Pertinent Findings a. Clinical i. Entering (unaided) VA, measured with LEA distance chart: OD: 20/54 OS: 20/23 ii. Cycloplegic retinoscopy: OD: +3.75 -2.00 x 180 OS: +2.25 -0.75 x 180 iii. Rx released: OD: +3.00 -2.00 x 180 OS: +1.50 -0.75 x 180 iv. Visual functions 1. Color vision: normal with F2 plates 2. Contrast sensitivity: 1.6% with Mr. Happy (normal) 3. Stereopsis: 120 sec with Stereo Smile (reduced) 4. Ocular motility: versions full, NPC TTN 5. Cover test: ortho at distance and near without glasses 6. Visual fields: full with confrontation VF testing 7. : ERRLA v. Ocular health 1. Anterior segment a. Lid margins/adnexa: clean and healthy b. Conjunctiva and sclera unremarkable c. : clear d. Anterior chamber: deep and quiet e. : clear f. : flat, (-) iris coloboma g. Digital IOP soft and equal 2. Posterior segment a. Optic nerve i. OD: large, inferior coloboma (-)SRF ii. OS: large, temporal optic disc pit b. Macula: flat and evenly pigmented OU c. Peripheral i. OD: 8 DD round inferior retinal coloboma with posterior border 1DD from optic nerve ii. OS: unremarkable b. Physical i. Color photos (obtained 2/12/2014) 1. Posterior pole OD, showing optic nerve coloboma 2. Inferior field OD, showing retinal coloboma 3. Posterior pole OS, showing optic disc pit ii. Cirrus OCT images (obtained 7/2/2014) 1. 5-line raster through ONH OD 2. 5-line raster through ONH OS 3. Macular cube OD/OS, showing normal macular thickness, no serous detachment or schisis iii. Goldmann visual field (planned, October 2014) III. Differential Diagnosis a. Primary/leading i. Optic nerve coloboma (OD) ii. Retinal coloboma (OD) iii. Congenital optic disc pit (OS) iv. Hyperopia, OD>OS b. Others i. Reduced visual acuity OD secondary to uncorrected refractive error DDx: refractive DDx: reduced acuity secondary to optic nerve coloboma IV. Diagnosis and Discussion a. Elaborate on the condition i. Optic Nerve Coloboma: Colobomas result from incomplete or abnormal coaptation of the proximal end of the embryonic fissure. Colobomas typically have a white, bowl-shaped excavation occupying an enlarged optic disc. The excavation is typically decentered inferiorly, reflecting the position of the embryonic fissure relative to the primitive epithelial fissure. The defect often extends further inferiorly to involve the retina. It can also be concurrent with an iris coloboma. Visual acuity may be mildly to severely decreased depending on the integrity of the papillomacular bundle. Colobomas present as a unilateral or bilateral condition with equal prevalence.

Unlike optic disc pits, colobomas are associated with many systemic anomalies, the most notable being CHARGE syndrome, but also including Walker-Warburg syndrome, Goltz focal dermal hypoplasia, Aicardi syndrome, Goldenhar sequence, and linear sebaceous nevus syndrome.

ii. Congenital optic disc pit: These are round or oval gray, white or yellow depressions within the optic disc. Optic pits are the herniations of dysplastic retina into a collagen-lined pocket extending posteriorly through a defect in the lamina cribrosa. They most commonly involve the temporal disc. They are often accompanied by adjacent peripapillary pigment changes and are unilateral conditions 85% of the time. Visual acuity is typically normal in the absence of subretinal fluid. Visual field defects are common – the most common ones being an enlarged blind spot and a paracentral . Serous macular elevations have been estimated to develop in 35-75% of eyes with optic pits.

b. Expound on unique features i. Both conditions are relatively rare, so it is very unusual to see both conditions in the same patient 1. Incidence of optic disc pit: 1/11,000 2. Incidence of optic nerve coloboma: 1/12,000 ii. Congenital optic disc pits and optic disc colobomas belong to the same group of excavated optic disc anomalies. Although similar in pathology, they are distinct anomalies with their own specific embryologic origin. iii. This unique presentation would suggest, as many authors have suggested, that optic pits are the mildest variant in the spectrum of optic disc colobomas. However, this is inconsistent with clinical findings. Each condition occurs at a specific time during development, carries its own set of associated risks and other anomalies.

V. Treatment, Management a. Treatment and response to treatment i. Plan for this patient 1. At her follow-up visit in July 2014, visual acuity in her right eye had improved from 20/54 to 20/27 2. F/U scheduled in October 2014, to re-check VA, stereo and perform Goldmann visual field ii. Monitor for risks associated with optic nerve colobomas: 1. Non-rhegmatogenous can occur a. Usually in the 2nd or 3rd decade b. Treatment involves peripapillary laser with PPV/air-gas/fluid exchange 2. Associated with many systemic abnormalities; CHARGE syndrome in particular should be ruled out in pediatric patients. iii. Monitor for risks associated with optic nerve pits: 1. Peripapillary atrophic changes, potential for CNV 2. In 40% of cases – patients develop a serous macular detachment or macular retinoschisis a. Mean age of onset variable range from 1st decade to 5th decade with mean age of 30 years b. Origin of fluid is uncertain c. When vision is reduced, laser treatment of the peripapillary area is indicated 3. Visual field defects a. Enlarged blind spot from having large disc b. Central scotoma from macular detachment c. Can mimic i. Arcuate scotoma ii. Localized constriction iii. Nasal/temporal steps iv. Paracentral scotoma v. Generalized constrictions b. Bibliography i. Borodic, GE, Gragoudas ES, Edward WO, Brockhurs RJ. Peripapillary subretinal neovascularization and serous macular detachment. Association with congenital optic nerve pits. Arch Ophthalmol. 1984 Feb; 102(2):229-31 ii. Brodsky, Michael C., Robert S. Baker, Latif M. Hamed. Pediatric Neuro-. Springer-Verlag. New York, NY. 1996. iii. Brown, Gary C. and William Tasman. Congenital Anomalies of the Optic Disc. Grune & Stratton. New York, NY. 1983. iv. Brown, Gary C. Augsburger JJ. Congenital pits of the optic nerve head. II. Clinical studies in humans. Ophthalmology. 1980 Jan; 87(1):51-65 v. Brown, Gary C. Shields JA, Patty BE, Goldberg RE. Congenital pits of the optic nerve head. I. Experimental studies in collie dogs. Arch Ophthalmol. 1979 Jul; 97(7):1341-4 vi. Kranenburg, EW. Crater-like holes in the optic disc and central serous retinopathy. Arch Ophthalmol. 1960. Dec; 64:912-24. vii. Nelson, Leonard B and Scott E. Olitsky. Harley’s Pediatric Ophthalmology. Lippincott Williams & Wilkins. Philadelphia, PA. 2014 viii. Ohno-Matsui, Kyoko, Akito Hirakata, Makoto Inoue, Masahiro Akiba, and Tatsuro Ishibashi. Evaluation of Congenital Optic Disc Pits and Optic Disc Colobomas by Swept-Source Optical Coherence Tomography. IOVS. Nov 2013: 54; 12 7769-7778. VI. Conclusion a. Clinical pearls: i. Although similar in appearance and pathology, optic nerve colobomas and optic disc pits are distinct entities, each with their own embryologic origin. ii. Optic nerve colobomas are associated with several systemic syndromes that should be considered if seen in a young patient. iii. Optic disc pits are not associated with any systemic conditions. iv. Both optic nerve colobomas and optic disc pits carry a risk of developing a serous macular detachment, most commonly in the 3rd decade of life, and should be monitored with careful fundus examination, automated perimetry, and Photos/OCT whenever possible.