September 2008

 

CATARACT/ IOL

 

Spontaneously resolved


by Matt Young EyeWorld Contributing Editor

   

Phacoemulsification unquestionably is a safe and effective procedure to remove cataracts. What if cataracts could spontaneously resolve themselves? The June 2008 issue of the Journal of Cataract & Refractive Surgery reports a case of spontaneous resolution of traumatic cataract after foreign body penetration.

“To our knowledge, this is the first case of spontaneous resolution of a cataract after capsule violation by an intralenticular foreign body,” wrote study co-author Cynthia S. Chiu, M.D., assistant professor of clinical opthalmology, Department of Ophthalmology, University of California, San Francisco. “The unique appearance of the cataract and its unusual resolution led to a new theory of lens injury by shockwave.”

What happened

A 49-year-old man was cutting wood with a table saw when he felt something hit his left eye. There was no pain or change in vision immediately, but he saw an ophthalmologist. UCVA was 20/20 in the right eye and 20/25 in the left, affected eye.

The diagnosis: A metal foreign body had perforated the sclera posterior to the iris. It penetrated the lens. The foreign body was 1.0 mm x 0.2 mm x 6.0 mm in size, and boomerang-shaped. “The foreign body protruded approximately 0.5 mm from the surface of the sclera and traveled through the pars plicata and equatorial lens capsule and was embedded in the peripheral lens cortex,” Dr. Chiu reported. “The remainder of the lens appeared normal, with no evidence of disruption.” This foreign body was extracted, and a small amount of vitreous that extruded from the sclera was removed. “On postoperative day 2, a 1+ posterior subcapsular cataract (PSC) and a small amount of vitreous hemorrhage adjacent to the area of injury without evidence of a retinal break were noted,” Dr. Chiu noted. “On day 4, in addition to the PSC, a dense cortical cataract had evolved, although the visual acuity remained 20/25. The cataract had a cruciate configuration with wave-like disruption of the stromal lamellae and a central apex presumably indicating the point of greatest impact.” That cataract wouldn’t last. “A week later, 1 month after injury, the patient subjectively felt his vision had improved. The visual acuity tested 20/25, and examination of the lens revealed resolution of more than 90% of the opacity,” Dr. Chiu wrote. “At 4 months, the patient continued to report improved vision, confirmed by a measured acuity of 20/20. On slitlamp examination, a small outpouching of the posterior lens capsule was noted and only a faint imprint of the original cataract remained.”

New theory

It’s well known that traumatic cataracts aren’t necessarily progressive, Dr. Chiu noted. But, clearly, it’s exceedingly rare for them to disappear. Although there have been reports of cataract resolution by natural means, no established theory described why this cataract did so.

“Closer analysis of the unique X-configuration of the cataract and the wave-like stromal disruption leads to another theory, one of temporary disturbance to the lens architecture without formation of a scar,” Dr. Chiu reported. “We hypothesize that most of the cortical opacity was not due to direct contact but to the misalignment of lens fibers from the propagation of a shockwave stemming from the missile. To borrow from another well-known intraocular phenomenon, we believe this is a case of lens sclopeteria.”

Once the lens capsule was sealed and “proper ionic balance had returned to the intralenticular space,” the lens architecture became normalized. “The small fraction of cells directly along the track of the foreign body, noted at the time of repair, likely sustained true cellular injury and has perpetuated in the form of a scar,” Dr. Chiu concluded. Many factors remain unexplained, such as whether prednisolone or the patient’s own healthy condition assisted recovery. Nonetheless, cataract by “shockwave” has an “excellent visual prognosis and justifies attempts at lens preservation after trauma,” Dr. Chiu reported. In all of his years performing cataract surgery, Mark Packer, M.D., clinical associate professor of ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, said he’s never seen anything like this. He noted, somewhat tongue-in-cheek, that he probably wouldn’t even have noticed this phenomenon because he would have phacoemulsified it before it had a chance to resolve. Then again, he said, “if it was non-progressive and not causing a problem with vision, then I wouldn’t have taken it out.” Dr. Packer said he had heard subjective reports of spontaneous resolution of cataracts but more often than not, the patients’ suspicions were unfounded. In some cases, he had to be the one to break the bad news.

Editors’ note: Dr. Chiu has no financial interests related to this study. Dr. Packer has no financial interests related to his comments.

Contact Information

Chiu: chiuc@vision.ucsf.edu

Packer: 541-687-2110, mpacker@finemd.com

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