History
A 42-year-old black male presented complaining of eye strain when reading during the last four months. His systemic and ocular histories were noncontributory, and he reported no allergies or taking medications of any kind.
Diagnostic Data
His best-corrected acuity was 20/20 O.U. at distance and near. External examination was normal, and there was no evidence of relative afferent pupillary defect in either eye. Refraction uncovered mild hyperopia with the onset of presbyopia.
Biomicroscopy revealed normal and healthy anterior segments. IOP measured 14mm Hg in both eyes. The significant posterior pole finding of the right eye is demonstrated in the photograph.
Your Diagnosis
How would you approach this case? Does this patient require additional tests? What is your diagnosis? How would you manage this patient? What is the likely prognosis?
Discussion
The diagnosis in this case is an uncomplicated optic pit in the right eye.
Additional tests include Amsler grid testing, frequency doubling perimetry and photodocumentation.
Many ophthalmic complications have been documented as a result of anomalous closure of the optic fetal fissure.1 Closure of the optic fetal fissure, which completes development of the globe, occurs during the fifth to seventh week of gestation.2 These anomalies have two possible etiologies: premature differentiation of the normally pleuripotent cells at the fissure margin, which leaves them unable to fuse, or accelerated growth of the inner wall of the optic cup, which causes excessive eversion of retinal tissue.3 Optic pits are thought to occur due to the latter mechanism. Another theory suggests that pits result from aberrant differentiation of the primitive epithelia papilla.3
Optic disc pits seem to have no common inheritance pattern or racial predilection.1 They can be passed on genetically, although it is not known if it is autosomal dominant or recessive.
Optic pits typically present temporally within the inferior portion of the nerve, although one-third present centrally.3 Optic pits vary in color, size, shape and depth. They are typically about 500m in size and in 85% of instances are unilateral. Usually, there is only one pit per eye, although two or three pits in the same eye have been reported.4
While the mechanism of their existence remains under investigation, pits in the optic nerve head clearly consist of nonfunctional, dysplastic retina that has luxated posteriorly through a defect in the lamina cribrosa.1 An optic pit may appear as an oval or round, gray, olive, yellow or whitish depression with varying amounts of hypopigmentation. Cilioretinal arteries may emerge from these pits. In these instances, for reasons that remain poorly understood, patients seem to be at greater risk for normal-tension glaucoma.3
Patients who have optic pits have a high incidence (40% to 60%) of non-rhegmatogenous serous macular detachments that can evolve into lamellar macular holes.3 The mechanism of the subretinal fluid penetration also remains under debate.5 One theory: Vitreal fluid leaks into the retina through the pit, causing a detachment.6
Newer theories suggest that pre-existing schisis-like lesions exist between the macula and optic disc, allowing any fluid that accumulates to gain access by filtering through the outer plexiform layer of the neurosensory retina.7 How and why the fluid gets there in the first place remain undetermined.7 Patients who have these maculopathies have an increased risk for a posterior vitreous detachment (PVD). Patients whose optic pits are located temporally possess the highest risk for retinal detachment.3 But, optic pit maculopathies without inner retinal schisis have been diagnosed.8
Differential diagnoses for optic pits include: tilted disc syndrome, posterior staphyloma, hypoplastic disc, scleral crescent, normal glaucomatous optic neuropathy/atrophy, as well as colobomas of the optic nerve or other optic nerve malformation. Because fluid accumulation in the macular area is consistent with the continuum of the process, central serous maculopathy and choroidal neovascularization should be considered as well.6
Treatment for optic pits includes photodocumentation of the nerve as well as baseline visual fields to assess the impact visual function and OCT to fully delineate alterations to the structure. Visual field compromise is common.3 In most patients, acuity remains unaffected and, despite the presence of correlating arcuate or paracentral scotomas, patients remain asymptomatic.
Finally, patients should be educated about the potential signs and symptoms of paramacular and macular involvement and told to seek attention at the first sign of intrusion. Provide a take-home Amsler grid so that the patient can detect the first signs of metamorphopsia or blurry vision.3
There is no treatment for the pit itself. But when optic pit-related macular detachment occurs, there are numerous treatment approaches: oral steroids, vitrectomy and prophylactic barrier laser photocoagulation.7 The most current trend in treatment is to use laser photocoagulation after the onset of maculopathy as well as a three-port pars plana vitrectomy, internal limiting membrane removal and expandable gas tamponade to help restore normal macular structure/function.5
Some surgeons argue that all epiretinal membranes along with the internal limiting membrane (ILM) should be removed in all optic pit patients who undergo therapy for a retinal detachment. This aids in the effort to reduce any and all tractional forces causing late retinal detachments associated with an epiretinal membrane or ILM contraction.9 In other studies regarding detachments around the macula, the same treatment is used without the laser.10,11
1. Irvine A, Crawford J, Sullivan J. The pathogenesis of retinal detachment with morning glory disc and optic pit. Retina 1986 Summer-Fall;6(3):146-150.
2. Barishak YR. Embryology of the eye and its adnexae. Dev Ophthalmol 1992;24:1-142.
3. Skorin L Jr. Optic disc pits can cause vision loss. Optometry Today 1999 Sep 24;9(1):35
4. Vedantham V. Double optic discs, optic disc coloboma, and pit: spectrum of hybrid disc anomalies in a single eye. Arch Ophthalmol 2005 Oct;123(10):1450-2.
5. Bakri SJ, Beer PM. Vitreoretinal surgery for optic pit associated serous macular detachment: a discussion of two cases. Int Ophthalmol 2004 May;25(3):143-6.
6. Besada E, Barr R, Schatz S, Brewer C. Vitreal pathogenic role in optic pit foveolar retinoschisis and central serous retinopathy. Clin Exp Optom 2003 Nov;86(6):390-8.
7. Johnson TM, Johnson MW. Pathogenic implications of subretinal gas migration through pits and atypical colobomas of the optic nerve. Arch Ophthalmol 2004 Dec;122(12):1793-800.
8. Moon SJ, Kim JE, Spaide RF. Optic pit maculopathy without inner retinal schisis cavity. Retina 2006 Jan;26(1):113-6.
9. Gotzaridis E. Perifoveal traction retinal detachment following successful optic disc pit surgery. Ophthalmic Surg Lasers 2002 May-Jun;33(3):243-5.
10. Hirakata A, Okada A, Hida T. Long-term results of vitrectomy without laser treatment for macular detachment associated with an optic disc pit. Ophthalmology 2005 Aug;112(8):1430-5.
11. Yang SS, McDonald HR, Everett AI, et al. Retinal damage caused by air-fluid exchange during pars plana vitrectomy. Retina 2006 Mar;26(3):334-8.
Thanks to Randy Fitzgerald, B.Sc., at Pennsylvania College of Optometry, for contributing this case.
