Resolution of Optic Disc Pit Maculopathy Following Posterior Vitreous Detachment

Abstract

Purpose:

This work presents a case of significant improvement of optic pit disc maculopathy following an acute posterior vitreous detachment (PVD) and discusses the possible mechanisms of this phenomenon.

Methods:

A case report and review of the literature are presented.

Results:

A 56-year-old man presenting with progressive visual decline in his left eye was found to have an optic disc pit with optical coherence tomography (OCT) evidence of severe intraretinal edema and maculoschisis. His visual acuity and macular anatomy on OCT improved dramatically in the months following a PVD.

Conclusions:

This report presents an interesting case of spontaneous improvement of optic disc pit–related maculopathy following PVD. We discuss the cause of the retinal fluid accumulation in optic disc pit maculopathy and consider that the OCT findings in our case lend credence to the theory that this fluid originates from the vitreous humor.

Introduction

Optic disc pit (ODP) is a congenital defect that is thought to result from an abnormality in the closure of the fetal fissure during embryogenesis. While often asymptomatic, it can lead to fluid accumulation in the retinal layers, known as ODP maculopathy (ODP-M). Various treatment options are available, including observation, laser photocoagulation, and vitreoretinal surgery. We present a case of spontaneous improvement of severe ODP-M after development of a posterior vitreous detachment (PVD).

Methods

Case Report

The patient was a 56-year-old man who had been aware of blurred central vision in his left eye for 1 to 2 years. He had recently been diagnosed with glaucoma and started on Travatan (travoprost) in both eyes. His medical history was significant for asthma, low testosterone, and hypothyroidism. He denied exposure to corticosteroids. The only ocular family history was glaucoma in his mother and brother. On examination, his vision was 20/25 OD and 20/60 OS. Intraocular pressure was 13 and 11 mm Hg in the right and left eyes, respectively. Slitlamp examination findings were normal. Fundus examination of the right eye showed a cup-to-disc ratio of 0.7 but otherwise normal macula and periphery (Figure 1A). Fundus examination of the left eye (Figure 1B) showed a syneretic vitreous without a posterior hyaloid detachment. The cup-to-disc ratio of the left eye was 0.6 with a possible ODP.

Figure 1.

Fundus photograph of the (A) right eye appearing normal and the (B) left eye showing a small inferior pole pit (arrow).

Macular evaluation revealed retinal pigment granularity in the fovea with intraretinal edema extending from the papillomacular bundle into the foveal center. Peripheral examination was unremarkable. Findings were confirmed by spectral-domain optical coherence tomography (OCT; Carl Zeiss Meditec), which showed a normal foveal contour in the right eye (Figure 2A) and posterior pole distortion in the left eye with prominent intraretinal cystic edema and schisis likely extending from the optic disc into the foveal center without subretinal fluid (Figure 2B). OCT and near-infrared imaging of the retinal nerve fiber layer were also performed and showed intraretinal fluid/schisis emanating from the inferotemporal edge of the optic disc (Figure 3A) and a likely inferior pole optic pit (Figure 3B), respectively. Intravenous fluorescein angiography (Optos) showed peripapillary hyperfluorescence at the inferotemporal edge of the optic disc with mild staining that increased slightly without obvious leakage (Figure 4). Given the constellation of findings and lack of a clearly visible ODP (likely owing to the small size of the pit and the marked deformity of the peripapillary retina from the degree of intraretinal fluid), a short empirical trial of bevacizumab was initiated, more so for a diagnostic purpose, to rule out a possible peripapillary/occult choroidal neovascular membrane.

Figure 2.

(A) Optical coherence tomography of the right eye, which appears to be normal. (B) Optical coherence tomography of the left eye showing posterior pole distortion with prominent intraretinal cystic edema and schisis likely extending from the optic disc into the foveal center without any subretinal fluid. N indicates nasal; T, temporal.

Figure 3.

(A) Optical coherence tomography of the retinal nerve fiber layer of the left eye showing intraretinal fluid/schisis emanating from the inferotemporal edge of the optic disc. (B) Near-infrared imaging of the retinal nerve fiber layer of the left eye visualizes the inferior pit. Arrow indicates the optic disc pit.

Figure 4.

Fluorescein angiogram at (A) early, (B) midphase, and (C) late stage showing peripapillary hyperfluorescence at the inferotemporal edge of the optic disc with mild staining that increased slightly without obvious leakage.

There was no significant improvement of his edema after 3 monthly injections. In fact, his vision dropped to 20/100 with the development of a prominent outer retinal defect involving the central macula as seen on OCT (Figure 5A). However, the day of his third scheduled injection, the patient complained of recent floaters and was found to have a PVD on clinical examination with a visible Weiss ring. Additionally, at that point, a small optic pit at the inferior edge of the optic disc was more clearly observed. His third injection was completed to finish the empirical trial. No further injections were given afterward, and the patient was monitored closely with serial photographs and OCT images every 2 to 3 months (Figure 5, B-D). Remarkably, his visual acuity (VA) and intraretinal edema dramatically improved over the following few months. At about 36 months after initial presentation his vision had increased to 20/30-1, and OCT showed a return of the normal foveal contour with a small area of central macular outer retinal layer discontinuity (Figure 5E). These findings remained stable at his last follow-up visit.

Figure 5.

(A) Optical coherence tomography (OCT) at 3 months after presentation showing an outer macular retinal break. (B) Six months after presentation, and shortly after a posterior vitreous detachment developed, OCT showed decreased central thickening. (C) Twelve months after initial presentation there was significant improvement in the macular thickening and intraretinal schisis and edema. (D) OCT at 1½ years after presentation showing a normal foveal contour with a small area of central macular outer retinal layer discontinuity.(E) Thirty-six months after presentation, there is return of the normal foveal contour with a decrease in the small area of outer retinal layer discontinuity. N indicates nasal; T, temporal.

Results

ODP is a congenital malformation that occurs with a prevalence of roughly 1 in 11 000, and the first reported case was in 1882. ¹ ODP presents with a “crater-like” depression of the retina at the optic disc. ¹ Although the exact embryological mechanism is not well understood, it is speculated that ODP arises from developmental abnormalities during closure of the optic fissure. ¹ ODP is most commonly diagnosed via ophthalmoscopy, which may reveal a retinal discoloration at the location of the pit. ¹

ODP can be an asymptomatic condition, but a reported 25% to 75% of patients present with ODP-M that results in blurry vision and worsened VA. ² While the exact mechanism of ODP-M formation is also not well understood, the disease is thought to occur via accumulation of fluid within the retina made possible by the appearance of the ODP. ² The level at which fluid accumulates within the retina is variable and can be classified as subretinal, intraretinal, or a combination of both. Treatment of ODP-M consists of surgical interventions that aim to increase retinal attachment to the choroid (laser photocoagulation and intravitreal gas injection), reduce the accumulation of retinal fluid (macular buckling surgery), or decrease vitreoretinal traction (pars plana vitrectomy [PPV] with induction of a PVD). ² More experimental procedures include creating an inner retinal fenestration to promote drainage of retinal fluid into the vitreous, as well as sealing the optic pit using patient-derived fibrin. ^3,4

There has been debate regarding the composition of the accumulated fluid in ODP-M, although studies suggest the most likely sources derive from vitreous humor or cerebrospinal fluid (CSF). CSF is seen as a possible origin because of the pitting of the retina through the cribriform plate and into the arachnoid space of the optic nerve. This theory is supported by the presence of communication between the subretinal and arachnoid spaces reported by Coll et al ⁵ in a patient presenting with morning glory syndrome. A retinal detachment in morning glory syndrome also has shown communication between the subretinal and arachnoid space, and surgical removal of the “dura window” resulted in subsequent resolution of retinopathy. ⁶ In another report providing evidence of a subretinal–arachnoid space communication, magnetic resonance imaging demonstrated the migration of silicone oil into the lateral ventricles of the brain following vitreoretinal surgery for proliferative vitreoretinopathy. ⁷

Vitreous humor is also postulated to be a likely source of retinal fluid. Communication between the subretinal and vitreous space has been demonstrated in multiple cases of ODP by migration of silicone oil into the subretinal space. ⁸ Age-related liquefaction of the vitreous during adulthood coincides with the onset of ODP-M in previously asymptomatic patients. Further support of this theory is the amelioration of ODP-M following PPV with induction of a PVD. In addition to laser photocoagulation, removal of the vitreoretinal traction via PPV and induction of PVD are some of the many common treatment options for ODP-M. ²

It is possible that the origin of the fluid varies between different cases of ODP-M. Interestingly, cases that supported the origin of fluid to be CSF present with more severe phenotypes (such as morning glory syndrome and bilateral ODP-M with early onset). Further understanding of the embryological mechanism could help improve clinical outcomes.

Our patient had spontaneous resolution of ODP-M following a PVD without the need for surgical intervention. This phenomenon has been observed previously by colleagues. ^9-11 Bloch et al ¹² surveyed many studies on ODP-M and discussed the disease’s natural history. Their analysis revealed that many untreated cases of ODP-M can retain good VA, with some even undergoing resolution of retinal fluid accumulation. Although we hypothesize that our patient’s ODP-M resolution was caused by PVD, we acknowledge that other less understood mechanisms may be responsible. Furthermore, we recognize the intravitreal injections of bevacizumab may have contributed to the development of PVD. Future research can further evaluate the possibility of enzymatic vitreolysis, such as with ocriplasmin, in the management of ODP-M.

Conclusions

Our patient presented with an interesting case of a severe ODP-M with progressive decline in vision. The patient worsened after a short empirical trial of bevacizumab that was performed secondary to diagnostic uncertainty and lack of a clearly identifiable ODP at initial presentation. Following a PVD, the patient’s ODP-M improved dramatically over the ensuing months. Given that the primary purpose of a PPV (which is often used to treat symptomatic patients) is to induce a PVD and release vitreous traction to the pit, we believe the PVD was the cause of our patient’s improvement. Causality is difficult to prove with certainty because of the variable natural history of the disease, but the temporal correlation and significant extent of his improvement suggest the PVD is more likely the cause. Finally, we believe that this case supports the theory that accumulated fluid in ODP-M originates from the vitreous humor and that a PPV with a detachment of the posterior hyaloid might be enough to treat ODP-M.