CONGENITAL OPTIC DISC PIT

Signs and Symptoms

A congenital optic disc pit (CODP) appears as a small, hypopigmented, yellow or whitish, oval or round excavated defect, most often within the inferotemporal portion of the optic disc. However, as CODP is considered to be an atypical coloboma (in that it is not limited to just the inferior disc region), it can appear anywhere within the boundaries of the disc. CODP width may range from 150 to 1000 microns, with an average size of 500 microns (1/3 of a disc diameter) and depths reaching as much as 0.16mm.1

CODP occur in one per 11,000 patients.1 Typically, a CODP is seen unilaterally, but the presentation is bilateral in 10-15% of cases.1,2 A large percentage of discs with congenital optic pits also have cilioretinal arteries.3 Discs with congenital pits are larger than fellow eyes without pits in 85% of cases.2,3 There is no apparent predilection for sex. In that they are congenital, their discovery typically coincides with a patient’s initial eye exam.4

Most patients are unaware of the presence of a CODP. Although many optic pits demonstrate arcuate scotomas on threshold visual field testing corresponding to the loss of retinal ganglion cells in the area of the pit, acuity is rarely affected by the pit itself. Patients with CODP are at risk of developing serous maculopathy affecting visual acuity. Should this occur, patients will notice visual blur and metamorphopsia. Those with temporally located pits are at the greatest risk for developing serous maculopathy.5

Maculopathy compromises vision in 25-75% of patients, typically occurring between the ages of 30-40 years.1,5,6 CODP maculopathy appears as a serous macular detachment of the sensory retina.3,6-15 However, careful observation aided by optical coherence tomography (OCT) has shown that the maculopathy caused by CODP is not limited to serous macular detachment, but also a retinoschisis-like splitting of the inner retinal layers.3,11,15-21

Pathophysiology

The origin of CODP remains unclear. CODP have been associated with colobomatous lesions, implying that they result from incomplete closure of the fetal fissure. The optic nerve is comprised of retinal ganglion cells, neuroectodermal layers of the optic stalk and its associated mesoderm. Failed development of the lamina cribrosa and its associated structures contribute to pit development.20 Arcuate visual field defects result secondary to the loss of the axons of the retinal ganglion cells, which correspond to the area of the pit or secondary atrophy of attenuated nerve fibers in the vicinity of the optic pit defect.

While the CODP itself is an unchanging entity, concern is directed toward the potential for associated serous maculopathy that can develop in up to 75% of patients with this congenital condition. While ophthalmoscopically the maculopathy manifests as a non-undulating, serous macular detachment, the pathology appears to be either a secondary event or an epiphenomenon from the development of inner nuclear layer macular retinoschisis.15,17,18,21

The origin of the serous submacular fluid is unknown, with hypotheses including cerebrospinal fluid from the subarachnoid space as well as liquefied vitreous from the vitreous cavity.16,22,23 It appears that an abnormal vitreoretinal interface inducing tangential tractional forces is the genesis behind the development of macular retinoschisis in CODP.16,19,24 Recently, optical coherence tomography (OCT) before and after vitreoretinal surgery for CODP maculopathy indicates that peripapillary vitreous traction with the passage of fluid into the retina through the pit is the cause of the schisis-like separation.25 Other OCT reports have indicated that fluid from the optic pit can go directly to the subinternal limiting membrane space, ganglion cell layer, inner nuclear layer, outer nuclear layer, or the subretinal space, although the outer nuclear layer is most commonly affected.26

Management

The management of asymptomatic CODP begins with threshold perimetry to document the existence of visual field loss. Photodocumentation is appropriate at this point.

Home acuity assessment and Amsler grid self-analysis should be used to monitor for the onset of maculopathy. Patients should be educated to the signs and symptoms of macular compromise (e.g., blurred vision, visual distortions and metamorphopsia) and instructed to return immediately should any occur.

The treatment for CODP-related maculopathy varies. Barrier thermal laser photocoagulation has been used in an attempt to halt the spread of subretinal fluid.8,10,14 However, most surgeons have abandoned thermal laser photocoagulation alone in favor of vitrectomy, either with or without adjunctive juxtapapillary barrier thermal laser photocoagulation.

There is no clear consensus on the management of CODP-related maculopathy. Due to the tangentially induced tractional forces by the posterior hyaloid causing foveal retinoschisis formation, pars plana vitrectomy with complete removal of all vitreoretinal adhesions is necessary for optimal treatment of macular detachment associated with optic pits.13,15,16,24 In several cases, serous maculopathy secondary to CODP resolved with spontaneous detachment of the posterior vitreous.27 There are numerous reports on successful management with vitrectomy combined with retinal tamponade by either expansive gas or silicon oil.1,3,6,7,9,10,13-15,19,22-24,28-31

Other studies have indicated the necessity of additionally peeling the internal limiting membrane (ILM) as part of the vitrectomy for optimal visual results.28,30-32 Another report, however, indicated ILM peeling is not necessary for good visual outcomes.33 At this time, serous retinal detachment occurring from CODP will be surgically treated with a combination of vitrectomy, barrier juxtapapillary retinal laser photocoagulation, ILM peeling and expansive gas tamponade.34 Visual and anatomical outcomes have been quite good, but can be slow. The restoration of the junction of the inner and outer photoreceptors is evident 6-12 months after surgery and is complete 24 months after fluid absorption. Improvement in vision is noticed only during the first two years of follow-up.35

Clinical Pearls

CODP may also appear in conjunction with other optic disc anomalies, including congenital coloboma and tilted disc syndrome.

Any changing of the appearance of the optic pit over time indicates the possibility that the lesion is actually an acquired defect of the neuroretinal rim secondary to glaucoma.

Due to the fact that the embryonic fetal fissure closes inferiorly last, typical colobomas occupy the inferior aspect of the disc. CODP are atypical colobomas in that they can occur anywhere on the disc.

Temporally located CODP are ominous in that they are at most risk for maculopathy development.

1. Kranenburg EW. Craterlike holes in the optic disc and central serous retinopathy. Arch Ophthalmol. 1960; 64(12):912-24.

2. Jonas JB, Freisler KA. Bilateral congenital optic nerve head pits in monozygotic siblings. Am J Ophthalmol. 1997;124(6):844-6.

3. Kolar P. Maculopathy in case of the pit of the disc. Cesk Slov Oftalmol. 2005;61(5):330-6.

4. Johnson KL. Optic disc pit: primary diagnosis in a child. Clin Exp Optom. 2006;89(4):257-9.

5. Brown GC, Shields JA, Goldberg RE. Congenital pits of the optic nerve head, II: clinical studies in humans. Ophthalmology. 1980(1);87:51-65.

6. Chiu YT, Chen HY, Tsai YY, et al. Stratus optical coherence tomography for evaluating optic disc pits associated with maculopathy before and after vitrectomy: two case reports. Kaohsiung J Med Sci. 2006;22(5):229-34.

7. Fantaguzzi PM, Vasco A. Vitrectomy and silicone oil tamponade for serous macular detachment associated with an optic disk pit. Eur J Ophthalmol. 2006;16(2):330-4.

8. Rosa AA, Primiano HP Jr, Nakashima Y. Pneumatic retinopexy and laser photocoagulation for treatment of optic disc pit detachment: case report. Arq Bras Oftalmol. 2006;69(1):101-5.

9. Hirakata A, Okada AA, Hida T. Long-term results of vitrectomy without laser treatment for macular detachment associated with an optic disc pit. Ophthalmology. 2005;112(8):1430-5.

10. Bakri SJ, Beer PM. Vitreoretinal surgery for optic pit associated serous macular detachment: a discussion of two cases. Int Ophthalmol. 2004;25(3):143-6.

11. Hassenstein A, Richard G. Optical coherence tomography in optic pit and associated maculopathy. Ophthalmologe. 2004;101(2):170-6.

12. Munteanu M, Munteanu G, Zolog I, et al. Colobomatous pits of the optic nerve papilla associated with serous retinal detachment. The clinical and pathogenic aspects. Oftalmologia. 2000;51(2):54-61.

13. Bartz-Schmidt KU, Heimann K, Esser P. Vitrectomy for macular detachment associated with optic nerve pits. Int Ophthalmol. 1995-96;19(6):323-9.

14. Montenegro M, Bonnet M. Optic nerve pits: clinical and therapeutic review of 21 cases. J Fr Ophtalmol. 1989;12(6-7):411-9.

15. Hirakata A, Hida T, Ogasawara A, et al. Multilayered retinoschisis associated with optic disc pit. Jpn J Ophthalmol. 2005;49(5):414-6.

16. Ishikawa K, Terasaki H, Mori M,et al. Optical coherence tomography before and after vitrectomy with internal limiting membrane removal in a child with optic disc pit maculopathy. Jpn J Ophthalmol. 2005;49(5):411-3.

17. Meirelles RL, Aggio FB, Costa RA, et al. STRATUS optical coherence tomography in unilateral colobomatous excavation of the optic disc and secondary retinoschisis. Graefes Arch Clin Exp Ophthalmol. 2005;243(1):76-81.

18. Morales Bertrand J, Teus Guezala MA, Perez Salaices P, et al. Congenital optic nerve pit associated with foveolar retinoschisis. Arch Soc Esp Oftalmol. 2001;76(5):327-30.

19. Kalvodova B, Ricarova R, Kuthan P, et al. Vitrectomy in optic nerve disc pit with maculopathy. Cesk Slov Oftalmol. 1999;55(3):123-7.

20. Krivoy D, Gentile R, Liebmann JM, et al. Imaging congenital optic disc pits and associated maculopathy using optical coherence tomography. Arch Ophthalmol. 1996;114(2):165-70.

21. Lincoff H, Schiff W, Krivoy D, et al. Optic coherence tomography of optic disk pit maculopathy. Am J Ophthalmol. 1996;122(2):264-6.

22. Kuhn F, Kover F, Szabo I, et al. Intracranial migration of silicone oil from an eye with optic pit. Graefes Arch Clin Exp Ophthalmol. 2006 Mar 8; [Epub ahead of print]

23. Johnson TM, Johnson MW. Pathogenic implications of subretinal gas migration through pits and atypical colobomas of the optic nerve. Arch Ophthalmol. 2004;122(12):1793-800.

24. Gandorfer A, Kampik A. Role of vitreoretinal interface in the pathogenesis and therapy of macular disease associated with optic pits. Ophthalmologe. 2000;97(4):276-9.

25. Hirakata A, Inoue M, Hiraoka T, McCuen BW 2nd. Vitrectomy without laser treatment or gas tamponade for macular detachment associated with an optic disc pit. Ophthalmology. 2012;119(4):810-8.

26. Imamura Y, Zweifel SA, Fujiwara T, et al. High-resolution optical coherence tomography findings in optic pit maculopathy. Retina. 2010 Jul-Aug;30(7):1104-12.

27. Bonnet M. Serous macular detachment associated with optic nerve pits. Graefes Arch Clin Exp Ophthalmol. 1991; 229(6):526-32.

28. Rizzo S, Belting C, Genovesi-Ebert F, et al. Optic disc pit maculopathy: the value of small-gauge vitrectomy, peeling, laser treatment, and gas tamponade. Eur J Ophthalmol. 2012;22(4):620-5.

29. Georgalas I, Petrou P, Koutsandrea C, et al. Optic disc pit maculopathy treated with vitrectomy, internal limiting membrane peeling, and gas tamponade: a report of two cases. Eur J Ophthalmol. 2009;19(2):324-6.

30. Pichi F, Morara M, Veronese C, et al. Double-vitrectomy for optic disc pit maculopathy. Case Report Ophthalmol. 2012;3(2):156-61.

31. Sandali O, Barale PO, Bui Quoc E, et al. Long-term results of the treatment of optic disc pit associated with serous macular detachment: a review of 20 cases. J Fr Ophtalmol. 2011;34(8):532-8.

32. Shukla D, Kalliath J, Tandon M, Vijayakumar B. Vitrectomy for optic disk pit with macular schisis and outer retinal dehiscence. Retina. 2012;32(7):1337-42.

33. Diab F, Al-Sabah K, Al-Mujaini A. Successful surgical management of optic disc pit maculopathy without internal membrane peeling. Middle East Afr J Ophthalmol. 2010;17(3):278-80.

34. Georgalas I, Ladas I, Georgopoulos G, Petrou P. Optic disc pit: a review. Graefes Arch Clin Exp Ophthalmol. 2011;249(8):1113-22.

35. Theodossiadis GP, Grigoropoulos VG, Liarakos VS, et al. Restoration of the photoreceptor layer and improvement of visual acuity in successfully treated optic disc pit maculopathy: a long follow-up study by optical coherence tomography. Graefes Arch Clin Exp Ophthalmol. 2012;250(7):971-9.