Crater an Abyss—Kranenberg Syndrome

Optic disc pit is a congenital disc anomaly due to failure of closure of superior edge of embryonic fissure during embryogenesis with accumulation of vitreous fluid in intra- and subretinal space.[1] It is sporadic, typically unilateral and 15% bilateral. Visual deterioration is associated with maculopathy and occurs in the third and fourth decades in 25–75% of temporal optic disc pits[2]; the development of maculopathy has no triggers and occurs at the time of vitreous liquefaction so vitreous traction is proposed to be a cause.[3] Immediate treatment for maculopathy involves laser photocoagulation at the temporal margin of optic disc pit. Intravitreal gas injection causes pneumatic displacement reattaching macula, macular buckling, pars plana vitrectomy, subretinal fluid drainage without retinotomy, ILM peeling (inverted) and PVD induction for visual restoration.[3] Incidentally, diagnosed disc pits are counselled for risk of maculopathy and advised on routine follow-up. Though spontaneous resolution of maculopathy is reported, prognosis is poor if not treated at the earliest.[2] PATIENT DESCRIPTION A 48 years’ male presented to OPD with chief complaints of left eye gradual progressive and painless defective vision for 2 months, no ocular and systemic co-morbidities. On examination, anterior segment was normal with BCVA RE 6/9 and LE 1/60, fundus examination showed LE well -defined greyish white round oval depression of approximately ¼ of disc size in the temporal aspect of disc with adjacent peripapillary changes shown as white arrow in Figure 1a; retinal vessels are normal, macula-circular well defined elevation of subretinal fluid collection shown as yellow arrow in Figure 1a with absent foveal reflex and RE normal. Diagnosed as LE optic disc pit maculopathy and OCT macula showed schitic oedema with sub- and intraretinal fluid collection.Figure 1: (a) Colour fundus photograph of case of LE optic disc pit maculopathy (ODP-M) showing a well-defined greyish-white defect in the disc suggestive of optic disc pit (white arrow) and serous fluid accumulation temporal to disc in macula (yellow arrow). (b) Spectral-domain optical coherence tomography of LE macular cube 30 degrees with line scan showing schitic oedema of inner retinal layers and neurosensory detachment with central macular thickness 614 micronsFinancial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.