CASE REPORT
A 12-year-old boy presented for a routine ophthalmic examination. The patient was asymptomatic on presentation. His past ocular history was significant for bilateral congenital cataracts which required bilateral cataract extraction by phacoemulsification with posterior chamber intraocular lens (PCIOL) implantation at 2 months of age.
There was no other relevant medical (topical or systemic medication) or surgical history. Despite this intervention, the patient developed bilateral amblyopia and had severe nystagmus when either eye was occluded.
At the time of the presentation, his visual acuity was hand motion in both eyes. Tonometry and specular microscopy were not possible given the degree of nystagmus.
A slit lamp examination of the right eye revealed a clear cornea with a fine pigmented line involving 360 degrees of the peripheral endothelium and a clear PCIOL.
The left eye revealed normal conjunctiva, a clear central cornea with 360 degrees of peripheral stromal corneal edema with microbullae without epithelial defect, or vascularization, and a clear PCIOL.
The rest of the ocular examination was normal. These findings were consistent with incipient Brown McLean Syndrome (BMS) in the right eye and established BMS in the left eye. The patient remained asymptomatic, and no further treatment was started at the time.
Brown McLean Syndrome disease entity
Brown-McLean Syndrome (BMS) describes a condition in which the peripheral (2-3mm) inferior cornea becomes edematous and progresses circumferentially, sparing the central cornea in most cases.
First described in 1969 as “peripheral corneal edema after cataract extraction,” it was later renamed to Brown-McLean syndrome.
Although it was initially believed to be associated with underlying endothelial dystrophy, further supported by a possible genetic predisposition as some cases of relatives presenting with this condition have been identified, no causative dystrophy or gene has been identified.
While its pathophysiology is still unknown, it was initially described in aphakic patients classically after intracapsular lens extraction. Most patients were elderly although patients as young as 12 years old have been reported.
It typically occurs several years after surgery, averaging 6-16 years post-operative. A genetic predisposition to endothelial disease, combined with endothelial trauma, has been proposed as a mechanism.
Other surgeries have been associated with BMS including PK, anterior chamber intraocular lens (ACIOL), phacoemulsification, and pars plana vitrectomy with lensectomy.
Interestingly, endothelial trauma is not necessary to induce Brown-McLean syndrome. Ultrasound biomicroscopy does not always reveal the presence of iridocorneal apposition and the presence of an iridectomy is not always reported as protective.
Non-surgical cases of BMS include patients who have had lens subluxation, spontaneous lens resorption, endothelitis, keratoconus, angle closure glaucoma, or myotonic dystrophy.
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From Choroida — the team behind this siteBrown McLean Syndrome management
Medical therapy
Most cases of Brown-McLean syndrome are responsive to hypertonic saline and topical steroids. Patients can also trial contact lenses, which have been shown to be well tolerated despite peripheral corneal edema.
Surgical therapy
For refractory or symptomatic cases, surgical management may be warranted. In recurring cases of epithelial bullae secondary to Brown-McLean syndrome, an annular amniotic membrane transplant using two trephines of different diameters placed basement membrane side up has been shown to be successful while maintaining central visual acuity.
Anterior stromal puncture with a 23-G or 25-G needle can be used as well to induce collagen expression thereby improving epithelial cell adhesion and subepithelial fibrosis, both of which improve blockade of fluid penetration into the corneal epithelium.
In the cases of ACIOL–associated BMS, treatment often includes the removal of the ACIOL for the resolution of the corneal edema. In untreated cases where central corneal decompensation occurs, a corneal transplant may be necessary.
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From Choroida — the team behind this siteREFERENCES
- Brown, S., and McLean, J. Peripheral corneal edema after cataract extraction a new clinical entity. Tr Am Acad Ophth Otol. 1969; 79:465.
- Brown, S. Peripheral Corneal Edema After Cataract Extraction. AJO. 1970; 70: 326-328.
- Charlin, R. Peripheral corneal edema after cataract extraction. Am J Ophthalmol. 1985; 99:298-303.
- Gothard T., Hardten D., Lane S., et al. Clinical findings in Brown-McClean Syndrome. Am J Ophthalmol. 1993; 115:729-737.
- Vote, B., Grupcheva, C., Ormonde, S., McGhee C. In vivo confocal microstructural analysis and surgical management of Brown McLean syndrome associated with spontaneous crystalline lens luxation. J Cataract Refract Surg. 2003; 29: 614-618.
Test yourself
A few questions straight from this article.
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Which part of the cornea is characteristically edematous in Brown-McLean syndrome?
BMS begins as edema of the peripheral 2-3 mm of the inferior cornea that spreads circumferentially, while the central cornea is spared in most cases. -
In which patients was Brown-McLean syndrome classically first described?
First reported as peripheral corneal edema after cataract extraction, BMS was initially described in aphakic patients, classically after intracapsular lens extraction. -
How long after surgery does Brown-McLean syndrome typically appear?
BMS typically develops several years after surgery, averaging 6-16 years postoperatively, so it can appear long after an uneventful recovery. -
What has research established about a genetic cause of Brown-McLean syndrome?
An underlying endothelial dystrophy and a familial predisposition were suspected, but no causative dystrophy or gene has been identified and the pathophysiology remains unknown. -
Which non-surgical condition has been associated with Brown-McLean syndrome?
Non-surgical BMS has been reported with lens subluxation, spontaneous lens resorption, endothelitis, keratoconus, angle-closure glaucoma and myotonic dystrophy. -
In a pseudophakic child, which slit-lamp sign indicated incipient Brown-McLean syndrome in the clear-cornea eye?
The right eye had a clear cornea with a fine pigmented line around 360 degrees of the peripheral endothelium (incipient BMS), while the left eye showed established peripheral stromal edema with microbullae. -
Which medical treatment are most cases of Brown-McLean syndrome responsive to?
Most BMS cases respond to hypertonic saline and topical steroids; contact lenses can also be trialled and are well tolerated despite the peripheral edema. -
For recurring epithelial bullae in refractory Brown-McLean syndrome, which procedure has succeeded while preserving central vision?
Surgery is reserved for refractory or symptomatic cases; an annular amniotic membrane graft cut with two trephines and placed basement-membrane side up has worked while maintaining central acuity. -
What does treatment of anterior chamber IOL-associated Brown-McLean syndrome often include?
In ACIOL-associated BMS, treatment often includes removing the ACIOL so that the corneal edema can resolve. -
When may a corneal transplant become necessary in Brown-McLean syndrome?
Because the central cornea is usually spared, keratoplasty is reserved for untreated cases in which central corneal decompensation occurs.
