Adverse effects
Bitter taste and nausea are more common than most other adverse effects.The oral suspension form produces a number of adverse effects including but not limited to:
Diarrhea
Abdominal pain
Rarely, tachycardia, bronchospasm, facial swelling, muscle achesBoth the oral suspension and the topical form can cause:

Hypersensitivity reactions, including Stevens–Johnson syndrome in some cases 
Rash, itching, burning and acute generalized exanthematous pustulosis

Mechanism of action
Like amphotericin B and natamycin, nystatin is an ionophore. It binds to ergosterol, a major component of the fungal cell membrane. When present in sufficient concentrations, it forms pores in the membrane that lead to K+ leakage, acidification, and death of the fungus. Ergosterol is a sterol unique to fungi, so the drug does not have such catastrophic effects on animals or plants. However, many of the systemic/toxic effects of nystatin in humans are attributable to its binding to mammalian sterols, namely cholesterol. This is the effect that accounts for the nephrotoxicity observed when high serum levels of nystatin are achieved. Nystatin also impacts cell membrane potential and transport by lipid peroxidation. Conjugated double bonds in nystatins structure steal electron density from ergosterol in fungal cell membranes. Lipid peroxidation alters the hydrophilicity of the interior of channels in the membrane, which is necessary to transport ions and polar molecules. Disruption of membrane transport from nystatin results in rapid cell death. Lipid peroxidation by nystatin also contributes significantly to K+ leakage due to structural modifications of the membrane. Biosynthesis
Nystatin A1 (or referred to as nystatin) is biosynthesized by a bacterial strain, Streptomyces noursei.
Bevacizumab is an anti-VEGF drug used in intravitreal injection that is known to cause reversal of sea fan lesions and reduce the duration of vitreous hemorrhage. Intravitreal injection of anti-VEGF drugs can also be used prior to surgery to aid separation of tissues involved in the sea fan lesion and to reduce intraoperative and postoperative hemorrhage. It is useful in combination with photocoagulation. Laser
Indications for laser photocoagulation include
Peripheral neovascularization of upwards of 60° circumference
Sickle cell retinopathy affecting both eyes
Large elevated sea fans
Rapid progression of neovascularizationThere are two methods of photocoagulation mainly used; feeder vessel coagulation and scatter laser coagulation. The first method closes the vessels that supply the neovascularized areas using laser burns. Both the xenon arc and argon laser can be used however, the argon laser carries a reduced risk of complications. In comparison, scatter laser coagulation has an indirect effect. Ischemic retina produces vascular endothelial growth factor (VEGF) which  promotes neovascularization. Scatter laser coagulation destroys this ischemic retina using laser burns thus preventing vitreous hemorrhage, retinal detachment and vision loss. Surgery
Surgical intervention is indicated for severely advanced disease that poses a threat to visual acuity. Indications include longstanding vitreous haemorrhage, vitreous haemorrhage in both eyes, vitreous haemorrhage in patients with only one eye, epiretinal membranes, macular holes and the various forms of retinal detachment. Scleral buckle was a previously popular surgical intervention however, its complications include anterior segment ischemia as a result of vascular occlusion. The vascular occlusion can in turn lead to phthisis bulbi.