Improvements in retinal imaging have recently elucidated structural patterns in the development of macular edema, particularly involving the inner nuclear layer. Here, the authors describe two cases of isolated inner nuclear layer cystic changes in the phakic fellow eye of patients with pseudophakic cystoid macular edema. Both cases improved with treatment of their fellow eye and resolution of contralateral macular edema. The authors hypothesize potential pathomechanisms for this likely common but under-recognized phenomenon.
[Ophthalmic Surg Lasers Imaging Retina. 2019;50:522–524.]
Pseudophakic cystoid macular edema (CME) is a common consequence of cataract extraction1,2 and is visually significant in 1% to 2% of uncomplicated surgeries.3 Angiographic CME occurs in up to 30%4 and has been attributed to soluble factors leading to increased perifoveal capillary permeability due to anterior segment inflammation. With recent high-resolution observations possible with spectral-domain optical coherence tomography (SD-OCT), isolated inner nuclear layer (INL) cysts have been discovered in a variety of disorders, including a presumed “retrograde synaptic degeneration” in optic neuritis and optic atrophy.5 The authors have recently observed isolated INL cystic changes in the phakic fellow eye of multiple patients presenting with acute CME.
A 67-year-old man presented with worsening visual acuity (VA) in his left eye (OS) 6 weeks following uncomplicated phacoemulsification with posterior chamber intraocular lens (IOL) implantation. The patient was maintained postoperatively on prednisolone acetate 1% and ketorolac tromethamine 0.5% both four times daily OS. Snellen best-corrected VA (BCVA) was 20/80 OS and 20/25 in the right eye (OD). Ophthalmoscopy revealed a well-placed, single-piece IOL with intact posterior capsule OS and moderate nuclear sclerosis with a normal anterior segment OD. Moderate iritis with absent vitritis was present OS. Posterior segment ophthalmoscopy revealed typical pseudophakic CME OS with a normal-appearing macula OD. Imaging characteristics are presented in Figure 1. The left eye was treated with 40 mg of posterior sub-Tenon's capsule triamcinolone acetonide. Four weeks later, repeat SD-OCT revealed a normal macula, and BCVA was 20/25 in both eyes.
Isolated inner nuclear layer (INL) cystic changes in the phakic fellow eye of a patient with pseudophakic cystoid macular edema (CME). (A) Arteriovenous phase fluorescein angiogram demonstrating mid-capillary perifoveal leakage 6 weeks after uncomplicated cataract extraction in the contralateral eye. (B) Recirculation phase demonstrating late and mild disc leakage. (C) Spectral-domain optical coherence tomography (SD-OCT) of the phakic unoperated eye displays isolated INL cysts (arrow). (D) The operative eye demonstrates typical pseudophakic CME. (E) Follow-up SD-OCT of phakic fellow eye demonstrating resolution of edema following treatment of and improved edema in the contralateral eye (F).
A 64-year-old female presented 1 month following uncomplicated phacoemulsification with IOL implantation OS with persistent decreased BCVA. The patient was maintained on postoperative prednisolone acetate and ketorolac tromethamine four times daily OS since surgery. BCVA was 20/60 OS and 20/40 OD. The left eye demonstrated typical CME with petalloid and disc angiographic leakage. The right eye demonstrated moderate nuclear sclerosis, normal posterior segment exam, and mild perifoveal leakage on fluorescein angiography. SD-OCT findings are presented in Figure 2. Four weeks following sub-Tenon's triamcinolone acetonide, the left eye demonstrated improved BCVA to 20/25 and normal SD-OCT; the right eye demonstrated slight improvement in BCVA to 20/30 with resolution of INL cystic changes.
Optical coherence tomography (OCT) of inner nuclear layer (INL) cystic changes in the phakic fellow eye of a patient with pseudophakic cystoid macular edema (CME). (A) Spectral-domain OCT of the right eye 1 month following uncomplicated cataract extraction in the fellow eye; isolated INL cystic changes are present in the perifoveal region (B). Contralateral postoperative eye with typical pseudophakic CME (C, D). One month following periocular corticosteroids in the postoperative eye, the cystic changes have resolved.
The observations presented herein indicate that phakic fellow eyes of patients with acute pseudophakic CME may develop isolated INL cystic changes with angiographic leakage. To our knowledge, this is the first report of this finding. Although it is difficult to accurately estimate its true incidence, six cases, including the two cases previously discussed, were discovered among 76 patients in the current imaging system database (8%). SD-OCT has led to the recognition of multiple recently described forms of INL cystic changes that are ophthalmoscopically imperceptible. These include delayed-onset INL cystic changes after internal limiting membrane peeling and presumed retrograde synaptic degeneration in optic neuritis,5 optic atrophy, and glaucoma.6
All patients demonstrated similar SD-OCT morphology and mid-capillary angiographic leakage in their contralateral phakic eye. The cystic changes were asymptomatic and resolved following treatment of the operative fellow eye in all cases. A subtle decline in vision was present in two cases, both of whom had moderately decreased BCVA due to underlying nuclear sclerosis that returned to baseline following cyst resolution. The distribution of cystic change appeared to correspond well with the location of fluorescein angiography leakage, and a small decline in central macular thickness was appreciated upon resolution in four out of six cases. None of the patients had a past history of ocular inflammation or vitreoretinal interface abnormality.
The pathogenesis of CME has long been postulated to arise from soluble inflammatory mediators inducing capillary hyperpermeability in an eye with mechanical iritis. A consensual ocular response to multiple unilateral stimuli has been suggested,7 including topical intraocular pressure medications, sympathetic ophthalmia, trauma, and inflammation.8 This may involve either a soluble systemic mediator reaching the fellow eye, a central neurovascular reflex, interophthalmic vascular communication, or axonal migration through the optic chiasm. This supports the notion that inflammation at any uveal or optic pathway location may induce macular INL cystic changes and may be a common subclinical SD-OCT finding in many inflammatory conditions. In our recent experience, the findings appear self-limiting and resolve quickly following treatment of the postoperative eye with periocular corticosteroids.
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- Henderson BA, Kim JY, Ament CS, Ferrufino-Ponce ZK, Grabowska A, Cremers SL. Clinical pseudophakic cystoid macular edema: Risk factors for development and duration after treatment. J Cataract Refract Surg. 2007; 33(9):1550–1558. doi:10.1016/j.jcrs.2007.05.013 [CrossRef]
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- El-Harazi SM, Feldman RM, Ruiz RS, Villanueva G, Chuang AZ. Consensual inflammation following ocular surgery. Ophthalmic Surg Lasers. 1999;30(4):254–259.