Optic disc pits (ODPs) are rare congenital anatomic defects in the optic disc present in one in 11,000 individuals. ODPs belong to a broader spectrum of congenital optic disc abnormalities, including optic disc coloboma, morning glory disc anomaly, and extrapapillary excavation.1 Cases of more than one ODP in the same eye are extremely rare, with only four reported cases in the literature.2–5 Double ODPs tend to be on the same side of the optic disc (temporally or inferotemporally), raising the possibility that they originate from the same underlying laminar defect. To our knowledge, only two cases of opposing pits have been reported, but neither with ancillary imaging.2,3 We present a case of unilateral, double ODPs involving opposite sectors in a patient with associated maculopathy using spectral-domain and wide-field optical coherence tomography (OCT) to image independent laminar defects as well as independent glial tufts associated with each pit.
A 35-year old Hispanic woman was referred for decreased vision in her left eye that began 2 weeks prior. Best-corrected visual acuities were 20/20 in the right eye (OD) and 20/40 in the left eye (OS). Fundus examination revealed a normal optic disc in the right eye and two optic disc pits in the left eye, one inferotemporally and one inferonasally. Intraretinal fluid involved two-thirds of the macula and also extended inferior and nasal to the disc. Spectral-domain OCT (SD-OCT) (Spectralis; Heidelberg Engineering, Heidelberg, Germany) confirmed the presence of significant intraretinal fluid.
Six months later, her vision was 20/30 OS. Her fundus appeared stable with two ODPs (Figure 1A). SD-OCT showed increased intraretinal fluid with splitting (schisis) of the outer retina (Figure 1B). Wide-field OCT (Avanti; Optovue, Fremont, CA) confirmed the presence of nasal intraretinal fluid (Figure 1C) and also showed two distinct ODPs with independent laminar defects and separate tufts of glial tissue (Figures 2A and 2B). Therapeutic options including observation, medical treatment, laser photocoagulation, and vitrectomy were discussed.
Two distinct optic disc pits are visible on funduscopy (back arrows); the border of intraretinal fluid is denoted with white arrows (A). Maculopathy and splitting (schisis) of the outer retinal layers is seen on optical coherence tomography (B). Intraretinal fluid extends nasally (C).
High-resolution optical coherence tomography (OCT) of the distinct optic pits with separate laminar defects and glial plugs, temporally, (A) and nasally (B) as indicated by arrows. Insets depict the cross-section level for each OCT image.
This is the first case of double ODPs in distinct sectors (nasal and temporal) imaged using OCT to show separate glial tufts associated with each pit. Histopathologically, ODPs consist of dysplastic retina accumulated in a pocket overlying the optic nerve that extends through a defect in the lamina cribrosa.6
Several theories have been suggested for their pathogenesis. Some have suggested that ODPs represent atypical colobomas, resulting from incomplete closure of the embryonic fissure or other anomalous embryological processes.7 Colobomas usually present nasally or inferonasally; however, the nasal pit in our case shows a localized invaginated structure, which speaks against a possible connection with a coloboma.8 Others have suggested that due to their presence in the temporal sector of the optic disc (usually inferotemporal) corresponding to the physiologic cup,4,5 excessive physiologic cupping may be a mechanism for their formation. Glaucoma-associated schisis has been attributed to laminar defects that are either a direct result from and/or worsened by glaucomatous damage.3,9 The presence of a pit on the nasal disc, which is only involved in the very late stages of glaucoma, may argue against excessive cupping as the exclusive mechanism by which ODPs form, although nasal schisis in the setting of glaucoma has been reported.9 The patient described herein presented to us with no history of glaucoma, no signs of glaucoma on examination in either eye, and normal intraocular pressures.
Another debated feature of ODPs is the source of fluid contributing to ODP-associated maculopathy. One theory proposes that cerebrospinal fluid from the subarachnoid space enters the intra- and subretinal spaces through the laminar defect.1 Indeed, recent OCT studies have confirmed connections between the subarachnoid and subretinal spaces in the presence of ODPs. Using swept-source OCT, Sambhav et al. showed the development of septa across the pit with signs of horizontal fissures.6 Pit-associated maculopathy has also been attributed to vitreous traction, as well as leaky papillary retinal and choroidal blood vessels.1
Glial tissue overlying ODPs can be found in 89% of patients.8 How glial tufts form in association with ODPs and the pathophysiologic role they play remains unclear. One possibility is that these tufts represent a scar formed as a result of vitreous traction. Removal of the glial tissue found in the pit during vitrectomy can be associated with resolution of the maculopathy (as can be vitrectomy alone), suggesting that removing the glial tuft is not detrimental to the outcome and may signify complete elimination of vitreous traction.8,10
Visually significant ODPs are uncommon and therefore difficult to study; the relationship between overlying presumed glial tissue and maculopathy is intriguing, but has not yet been well established. Further studies, aided by the recent advances in retinal and optic disc imaging modalities, are needed to better define the underlying cause, delineate the pathophysiology, and refine the treatment of this visually threatening disease.
- Moisseiev E, Moisseiev J, Loewenstein A. Optic disc pit maculopathy: When and how to treat? A review of the pathogenesis and treatment options. Int J Retina Vitreous. 2015;1(1):13. doi:10.1186/s40942-015-0013-8 [CrossRef]
- Malik R. Bilateral multiple congenital pits in the optic disc with opaque nerve fibers and maculopathy. J All India Ophthalmol Soc. 1969;17(3):117–119.
- Jonas J, Naumann G. [Pits of the optic papilla in large optic nerve papillae. Papillometric characteristics in 15 eyes]. Klin Monbl Augenheilkd. 1987;191(4):287–291. doi:10.1055/s-2008-1050511 [CrossRef]
- Choudhry N. Double optic pit maculopathy. Ophthalmic Surg Lasers Imaging Retina. 2015;46(2):284–286. doi:10.3928/23258160-20150213-05 [CrossRef]
- Ali Z, Abdul-Nabi M. A rare case of symptomatic double optic disc pit without maculopathy. Case Rep Ophthalmol Med. 2016;2016:2560568.
- Sambhav K, Grover S, Chalam KV. Swept source optical coherence tomography validates lamina cribrosa anomaly in optic disk pit. Retin Cases Brief Rep. 2016Sep22. [Epub ahead of print]. doi:10.1097/ICB.0000000000000410 [CrossRef]
- Smelser GK. System of ophthalmology, vol 3, normal and abnormal development; part 1: Embryology. Arch Ophthalmol. 1965;74(4):553. doi:10.1001/archopht.1965.00970040555023 [CrossRef]
- Gregory-Roberts EM, Mateo C, Corcóstegui B, et al. Optic disk pit morphology and retinal detachment: Optical coherence tomography with intraoperative correlation. Retina. 2013;33(2):363–370. doi:10.1097/IAE.0b013e318263d0a6 [CrossRef]
- Hubschman J, Reddy S, Kaines A, Law S. Nasal retinoschisis associated with glaucoma. Ophtalmic Surg Lasers Imaging. 2010;9:1–4.
- Inoue M, Shinoda K, Ishida S. Vitrectomy combined with glial tissue removal at the optic pit in a patient with optic disc pit maculopathy: A case report. J Med Case Rep. 2008;2:103–103 doi:10.1186/1752-1947-2-103 [CrossRef]