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Letters
 
 

Bilateral Patching and Vitreous Hemorrhage 

I was surprised no mention of bilateral patching was made in “Vitreous Hemorrhage: Diagnosis and Treatment” (Ophthalmic Pearls, March 2007).

Unfortunately, reaching for a B-scan probe appears to be the management of choice in many residency programs, while a demonstration of “no retinal tear or detachment” is frequently followed by a series of similar studies.

The recommendation of an immediate B-scan ultrasonogram is problematic for several reasons—breaks are quite difficult to detect even in expert hands, retinal detachments take time to occur—and following these patients with serial ultrasound studies until a detachment occurs can result in delayed diagnoses, increased rates of macular involvement and preoperative proliferative vitreoretinopathy rates that approach 50 percent.1–3

The best data regarding vitreous hemorrhages in the nondiabetic population demonstrate that retinal tears occurred in more than half of cases. Approximately three-fourths were horseshoe tears that usually led to retinal detachment, and almost 90 percent were located superiorly where they might have been seen following bilateral patching.1

Bilateral occlusion of eyes with overnight patching usually allows for both an examination of most of the superior 160 to 180 degrees within a few hours and visualization of the superior retina (and an opportunity for immediate therapy) in 50 to 80 percent of cases.2,3

Head elevation may be of some value. However, bilateral patching is much more critical. The patient must be assisted in ambulation following patching at bedtime, and patches should be immediately reapplied following mydriatic drop installation the next morning.

C. P. Wilkinson, MD
Baltimore

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1 Sarafizadeh, R. et al. Ophthalmology 2001;108:2273–2278.
2 Lincoff, H. et al. Retina 2004;24:246–253.
3 Wilkinson, C. P. Retina 2005;25:395–396.

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Crystalline Keratopathy Follow-Up 

The recent story “Crystalline Keratopathy: Spectrum of Disease, Diagnosis and Treatment” (Ophthalmic Pearls, January) was an excellent review of the subject. While I appreciate the authors’ references to articles I have written, I would like to add some clarifications and corrections.

The authors reference the Swedish and Finnish pedigrees I first described in 1992. Based on my follow-up of 115 patients with Schnyder crystalline corneal dystrophy (SCCD), I have now found that SCCD may occur in many other ethnicities and racial groups, including Asians and African-Americans.1

In addition, our referenced work analyzing the lipid content of these corneas did, in fact, find that cholesterol and phospholipids were increased 10-fold and fivefold, respectively. However, this was not necessarily related to crystalline deposits.

Regarding the table included in the article: While photophobia is a frequent complaint, ocular irritation is an infrequent symptom.

The presence or absence of crystals in SCCD has made this disease very misunderstood. SCCD is an important corneal disease to have in the differential diagnosis if corneal crystals are found. It is extremely important to emphasize that only approximately half of patients with SCCD have corneal crystals. Because many clinicians are unaware that SCCD without crystals can occur, SCCD patients who have corneal opacifications without the crystalline deposits are often misdiagnosed.

While most patients with SCCD experience a very gradual decrease of vision with a disproportionate loss of photopic visual acuity, phototherapeutic keratectomy is only a helpful treatment for those SCCD patients with crystalline deposits that cause vision loss or photophobia. Moreover, crystals may recur and corneal opacification may progress regardless of phototherapeutic keratectomy. I found that more than 54 percent of patients who were 50 years of age or older reported having penetrating keratoplasty, the treatment of choice in patients with visual decrease resulting from progressive corneal opacification.

Those members of SCCD pedigrees without the corneal dystrophy also possess systemic lipid abnormalities. Consequently, both affected and unaffected members of SCCD families should have serum lipid studies performed.

Jayne S. Weiss, MD
Detroit

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1 Weiss J. S. Trans Am Ophthalmol Soc 2007;105:616–648.

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