Surgical outcome in optic disc pit maculopathy.

The purpose of this study was to present the surgical outcome in optic disc pit associated maculopathy in a patient who was treated with vitrectomy, internal limiting membrane (ILM) peeling, barrage laser photocoagulation, and silicone oil tamponade. A 21-year-old Indian male was diagnosed with optic disc pit maculopathy in his left eye with a best-corrected visual acuity (BCVA) of 20/200. A 23-gauge pars plana vitrectomy with peeling of ILM was done using brilliant blue dye. After completion of vitrectomy, fluid-air exchange was performed and silicone oil was instilled into eye. Peripapillary endolaser barrage photocoagulation using two rows of low-intensity laser was performed temporally. Silicone oil was removed 4 months after surgery. During the next 24 months, the retina gradually flattened with gradual improvement of BCVA in the left eye. At 24 months, fundus examination showed retinal pigment epithelium atrophy temporal to optic disc not involving the fovea, and optical coherence tomography showed complete resolution of subretinal fluid, with a BCVA of 20/60. The patient maintained the same vision 4 years following the surgery. vitrectomy combined with posterior hyaloid and ILM peeling followed by silicone oil tamponade, with additional laser photocoagulation, was successful for the treatment of optic disc pit maculopathy in our patient. Further studies are warranted to explore the various treatment options and try to set a standard treatment protocol for this rare challenging condition.

Introduction

Optic disc pits are congenital excavations of the optic nerve head. In 1982, Weithe was the first to report a bilateral case of optic disc pit in a 62-year-old women.[1] Optic disc pits are usually gray in color but may vary from yellow to black in some cases. About 70% of the optic disc pits are seen in the temporal aspect of the optic nerve head and about 20% are situated centrally; remainder is found inferiorly, superiorly, and nasally.[2] Blurring of vision is the most common presenting complaint and is seen in about 66% of the patients, which occurs due to serous macular detachment in these patients.[2] Chronic cystoids' changes in the macula and development of subretinal precipitates may be seen due to long-standing serous retinal detachment. Through the analysis of stereoscopic transparencies, it has been proposed that the fluid that enters through the optic disc pit actually travels between the inner and outer layers of the retina to produce a retinoschisis.[3] Some recent published articles have shown that macular traction and posterior vitreous detachment may be involved in the pathogenesis of optic disc pit maculopathy.[4]

We report a case of optic disc pit associated with serous macular detachment in a 21-year-old Indian male who underwent 23G vitrectomy with internal limiting membrane (ILM) peeling and silicone oil tamponade.

Case Report

A 21-year-old Indian male presented with diminution of vision in his left eye for 1 month. Best-corrected visual acuity (BCVA) in the right eye was 20/20 and in the left eye 20/200. On slit-lamp examination, no abnormality was detected in anterior segment, and intraocular pressure was 14 mmHg in both the eyes. On fundus examination, serous macular detachment was seen in the left eye with an optic disc pit on the temporal aspect of optic nerve head [Figure 1]. The optic disc and fundus examination of right eye were normal. The spectral domain optical coherence tomography (SD-OCT) (Carl Zeiss Meditec, Inc.) was done which showed serous macular detachment and retinoschisis in the left eye [Figure 2]. Central macular thickness was 942 microns with cube volume of 19 mm.[3] A 23-gauge pars plana vitrectomy with peeling of ILM was done using brilliant blue dye. After completion of vitrectomy, fluid-air exchange was performed and silicone oil was instilled into eye. Peripapillary endolaser barrage photocoagulation using two rows of low intensity laser was performed temporally. Silicone oil was removed 4 months after surgery. During the next 24 months, the retina gradually flattened [Figure 3a–c] with gradual improvement of BCVA in the left eye. At 24 months, fundus examination showed retinal pigment epithelium atrophy temporal to optic disc not involving the fovea [Figure 4] and SD-OCT showed complete resolution of subretinal fluid [Figure 5] with a BCVA of 20/60. The patient maintained the same vision 4 years following the surgery.

Figure 1

Fundus photo at baseline

Figure 2

Optical coherence tomography at baseline

Figure 3

(a) Optical coherence tomography 3 months after surgery, (b) optical coherence tomography 10 months after surgery, (c) optical coherence tomography 18 months after surgery

Figure 4

Fundus photo after 24 months after surgery

Figure 5

Optical coherence tomography 24 months after surgery

Discussion

Optic disc pit is an rare congenital anomaly of the optic nerve head which may complicate into serous retinal detachment of the posterior pole.[3] The source from which this subretinal fluid comes is not fully understood. Some believe that this fluid comes from vitreous cavity itself, and some hypothesize that it is actually the cerebrospinal fluid that tracks from subarachnoid space and some believe that fluid leaks from blood vessels at the optic disc pit.[567] How this fluid get accumulated under the retina is unknown. However, it is believed that the fluid first forms a schisis cavity and following this detachment of the outer retinal layer may occur as a secondary process.[3] Twenty-five percent of cases with optic disc maculopathy resolve spontaneously.[8] However, the poor visual outcome which is associated with chronic serous retinal detachment in these patients, many surgeons prefer early and active treatment strategy.[9] There is no standardized protocol for this disease entity. Some prefer doing only barrage laser temporal to optic disc, while others prefer to do vitrectomy with or without peeling of ILM. In one study, Shukla et al. performed vitrectomy with ILM peeling followed by barrage laser photocoagulation and they used C3F8 as internal tamponade agent in their patients.[10] Although good visual acuity was achieved in most of their patients, but they encountered macular hole in more than 50% patients, which they thought could be attributed to ILM peeling. In our case, the same surgical technique was used except that we used silicone oil instead of gas tamponade because the patient was resident of high altitude area. Vitrectomy with/without ILM peel, with/without gas tamponade, and with or without endolaser photocoagulation has also been shown to improve vision. Although many treatment options are available, none of them has proved to be superior. Our treatment included 23-gauge vitrectomy, posterior hyaloid and internal membrane peeling, silicone oil tamponade, and laser photocoagulation. Some surgeons prefer surgical treatment without the use of laser photocoagulation. Hirakata et al. performed vitrectomy with gas tamponade and did not use laser treatment and they found improvement in visual acuity in their patients.[11] They suggested that it was the peripapillary traction of vitreous on retina that allowed the passage of fluid through the pit into subretinal space. On the other hand, some authors prefer to add laser photocoagulation to their patients. Avci et al. performed vitrectomy, with barrage laser photocoagulation, and C3F8 gas tamponade in their patients and showed success rate in their patients both visually and anatomically.[12] We used laser photocoagulation in our patient because photocoagulation can seal the communication between the optic disc pit and subretinal space and is thus important in blocking the passage of fluid into subretinal space. In the absence of any standard protocol of treatment, one may start with laser photocoagulation and progress to surgery if the maculopathy fails to resolve. It is also unclear whether morphological changes such as retinoschisis, outer retinal dehiscence, or neurosensory detachment are an indication of earlier and more aggressive treatment.

In conclusion, vitrectomy combined with posterior hyaloid and ILM peeling followed by silicone oil tamponade, with additional laser photocoagulation was successful for the treatment of optic disc pit maculopathy in our patient. Further studies are warranted to explore the various treatment options and try to set a standard treatment protocol for this rare challenging condition.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.