BASICS

DESCRIPTION

A rare, usually unilateral, congenital excavation of the optic nerve head that can be associated with a serous macular detachment.

EPIDEMIOLOGY

Prevalence

• Approximately 1 in 10,000 eyes

• Men and women affected equally

RISK FACTORS

No risk factors have been conclusively identified.

Genetics

Most cases are sporadic, but a few reports of autosomal dominant pattern of inheritance.

PATHOPHYSIOLOGY

• 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.

DIAGNOSIS

HISTORY

• 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).

PHYSICAL EXAM

• 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.

Pediatric Considerations

Watch for amblyopia in children, especially in eyes with serous macular detachment.

DIAGNOSTIC TESTS & INTERPRETATION

Imaging

• 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

DIFFERENTIAL DIAGNOSIS

• 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

TREATMENT

SURGERY/OTHER PROCEDURES

• 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

ONGOING CARE

FOLLOW-UP RECOMMENDATIONS

• 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

PROGNOSIS

• 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.

COMPLICATIONS

Serous retinal detachment in macula.

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