A rare, usually unilateral, congenital excavation of the optic nerve head that can be associated with a serous macular detachment.
• Approximately 1 in 10,000 eyes
• Men and women affected equally
No risk factors have been conclusively identified.
Most cases are sporadic, but a few reports of autosomal dominant pattern of inheritance.
• Optic disc originates from the optic cup when the optic vesicle invaginates and forms an embryonic fissure (or groove).
• Optic pits may develop due to failure of the superior edge of the embryonic fissure to close completely.
• Two-layered maculopathy consisting of a primary inner retinal layer schisis and a secondary outer layer detachment
• Mechanism of macular detachment.
– Previously proposed that cerebrospinal fluid leaked through optic pit into subretinal space subarachnoid space
– Widely accepted that liquefied vitreous fluid leaks through optic pit into subretinal space
– One alternative theory suggests direct communication between optic pit and retina, causing schisis-like separation with a secondary accumulation of subretinal fluid.
– Vitreomacular or vitreopapillary traction may play a role in fluid entry into retina from optic pit.
COMMONLY ASSOCIATED CONDITIONS
Rarely associated with basal encephalocele.
• Asymptomatic if isolated. Usually an incidental finding on examination
• If serous macular detachment, may notice blurred vision, distortion, blind spot, or micropsia
• When symptomatic for subretinal fluid, most eyes present with visual acuity between 20/40 to 20/60 (1).
• Small, round, hypopigmented, grayish, excavated depression in the optic nerve head
• Bilateral in 10–15% of cases
• 70% located on temporal side of disc, 20% located centrally (2).
• More commonly seen in larger optic discs
• Adjacent peripapillary chorioretinal atrophy
• White or gray membrane overlying pit
• Visual field defects: Arcuate scotoma is most common
• Serous retinal detachment extending from the disc to the macula
– Estimated 40–50% of pits
– More commonly when pit is large and located in temporal region of disc
– Rare with small pits and located more centrally
– Most confined between superior and inferior arcades in macula and are contiguous with optic disc, sometimes through a small isthmus of subretinal fluid
– Serous detachments are generally low (<1 mm in height) and contain cystic regions.
Watch for amblyopia in children, especially in eyes with serous macular detachment.
DIAGNOSTIC TESTS & INTERPRETATION
• Baseline visual field testing
• Optical coherence tomography
– Typically shows schisis-like separation between inner and outer retina and subretinal fluid
• Fluorescein angiography
– Unremarkable with no dye accumulation in area of serous detachment, but may have late hyperfluorescence of the optic pit
– Rule out choroidal neovascular membrane or central serous chorioretinopathy
• Acquired pit (pseudopit): Can be seen in low-tension and primary open-angle glaucoma
• Optic disc anomalies such as scleral crescent
• Tilted disc syndrome
• Circumpapillary staphyloma
• Central serous chorioretinopathy and subretinal neovascular membrane in setting of serous macular detachment
• Laser photocoagulation
– One or several rows of light laser burns between the area of serous retinal detachment and the optic disc
– Several studies reported successful resolution of serous detachment, but this outcome did not always translate into improved visual outcome (3).
• Macular buckling
– Converts posterior hyaloid traction from an inward to an outward vector, which leads to reattachment of the macula
• Posterior vitrectomy, internal tamponade, and photocoagulation (4,5)
– Most encouraging long-term visual outcomes
– Induction of posterior vitreous detachment helps relieve vitreous traction
• Isolated optic pits
– Yearly dilated fundus examination and visual field testing if indicated
– Amsler grid
• Optic pits with serous macular detachment
– Reexamine 3–4 weeks after treatment to check for fluid resorption
– Watch for amblyopia in children
• Optic nerve head pits are stationary, but associated retinal complications such as serous macular detachment can be progressive.
• In a series by Brown et al, mean visual acuity at 5 years was 20/80 (2).
• In a study by Sobol et al, most patients lost 3 or more lines of vision within the first 6 months of presentation. With long-term followup, only 20% of patients maintained visual acuities better than 20/200 (1).
• Spontaneous macular reattachment can occur in rare instances, especially in eyes undergoing posterior vitreous separation.
Serous retinal detachment in macula.
1. Sobol WM, Blodi CF, Folk JC, et al. Long-term visual outcome in patients with optic nerve pit and serous retinal detachment of the macula. Ophthalmology 1990;97:1539–1542.
2. Brown GC, Shields JA, Goldberg RE. Congenital pits of the optic nerve head. II. Clinical studies in humans. Ophthalmology 1980;87:51–65.
3. Theodossiadis G. Evolution of congenital pit of the optic disc with macular detachment in photocoagulated and nonphotocoagulated eyes. Am J Ophthalmol 1977;84:620–631.
4. Schatz H, McDonald HR. Treatment of sensory retinal detachment associated with optic nerve pit or coloboma. Ophthalmology 1988;95:178–186.
5. Johnson TM, Johnson MW. Pathogenic implications of subretinal gas migration through pits and atypical colobomas of the optic nerve. Arch Ophthalmol 2004;122(12):1793–1800.