Optic Nerve Pit – January 2016

January 2016

Case Presentation

A healthy 26-year-old male was referred to Illinois Retina Associates for macular edema in his right eye. He has mild myopia, but was otherwise healthy and took no medications. He noticed visual distortion in his right eye for two months.

He received three bevacizumab (Avastin) injections with no improvement of his symptoms but an outside retina specialist.

Posterior Segment Exam

On examination, visual acuity was 20/20 OU, but the patient complained of metamorhpopsia OD. An optic nerve pit was identified along the inferotemporal rim (Figure 1) of the optic nerve head. There was a serious retinal detachment with subretinal exudates extending from the optic nerve towards the macula (Figure 1).

Figure1
Figure 1

 

Diagnostic Testing

A macular spectral domain optical coherence tomography scan (OCT) showed intraretinal and subretinal fluid in the macular area (Figure 2). Fluorescein angiogram (FA) revealed extensive leakage in the macula (Figure 3).

Figure5
Figure 2
Figure6
Figure 3

Differential Diagnosis

  • Optic nerve pit associated maculopathy
  • Central serous chorioretinopathy
  • Idiopathic juxtapapillary choroidal neovascularisation
  • Myopic degeneration with choroidal neovascularisation
  • Uveal effusion syndrome
  • Neuroretinitis

Diagnosis

Optic Nerve Pit

Discussion

Optic nerve pits are small congenital optic nerve cavities. They are rare, occurring in less than 1/10,000 patients, with 15% of cases being bilateral. The main complication of optic disease pits is optic disc pit maculopathy (macular edema and subretinal fluid), occurring in up to 2/3 of patients, and presenting in early adulthood. The typical presentation consists of schisis-like cavities in the outer retina, and can also be associated with subretinal fluid. In a minority of cases there can be spontaneous improvement, however, poor visual outcomes have been described in untreated patients.

There are a few hypotheses attempting to explain the origin of the macular fluid:

  • Fluid from the vitreous cavity
  • Cerebrospinal fluid from the subarachnoid space
  • Leaky blood vessels at the pit base
  • Fluid from the orbital space surrounding the optic nerve dura
  • Component of vitreoretinal transaction

A number of treatments, performed either alone, or in combination with vitrectomy, have been described, including:

  • Observation
  • Peripapillary laser, in an attempt to limit passage of fluid into the macula
  • Intravitreal gas injection, which could promote fluid resorption through tamponade
  • Pars plana vitrectomy, thought to relieve traction from the vitreoretinal interface
  • Closing the pit with tissue glue or atuologous platelet concentrate during vitrectomy, thus preventing intraocular and/or subarachnoid fluid from entering the pit
  • Internal limiting membrane peeling
  • Unroofing the pit or creating inner retinal fenestrations, to equalize pressure differential between inside the eye and the subarachnoid space and avoid fluid from being pushed into the retina.
  • Macular buckle surgery

Modern vitrectomy procedures have been good long term outcomes and result in visual improvement in a majority of patients.

References

GNadal J et al. Autologous platelet concentrate in surgery for macular detachment associated with congenital optic disc pit. Clin Ophthalmol. 2015 Oct22;9:1965-71.doi:10.2147/OPTH.S81976.eCollection 2015

Talli PM et al. Victrectomy without laser treatment for macular serous detachment associated with optic disc pit: long-term outcomes Eur J Ophthalmmol. 2015 Sep 18:0.doi: 10.5301/ejo.5000680.[Epub ahead of print]

Abbouamoh MA et al. Pars plana vitrectomy with juxtapapillary laser photocoagulation versus vitrectomy without juxtapapillary laser photocoagulation for the treatment of optic disc pit maculopathy: the results of the KKESH International Collaborative retina Study Group Br J Ophthalmol.2015 Aug 20.pii:bjophthalmol-2015-307128.doi: 10.1136/bjophthalmol-2015-307128. [Epub ahead of print]

Teke MY et al. 23 Gauge Vitrectomy, Endolaser, and Gas Temponade Versus Vitrectomy Alone for Serous Macular Detachment Associated With Optic Disc Pit. Am J Ophthalmol.2015 Oct;160940:779-85.e2.doi: 10.1016/j.ajo.2015.07.019.Epub 2015 Jul 21

Rayat JS et al. LONG-TERM OUTCOMES FOR OPTIC DISK PIT MACULOPATHY AFTER VITRECTOMY. Retina. 2015 Oct;35(10):2011-7

Theodossiadis GP. Macular buckling in optic disc pit maculopathy in association with the origin of macular elecation: 13-year mean postoperative results. Eur J Opthalmol. 2015 May-Jun;25(3):241-8.doi: 10.5301/ejo.5000553.Epub 2015 Jan 1