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We read with interest the study that compared intraoperative mitomycin C to beta irradiation in primary pterygium surgery.
The authors rightly commented that long term complications of beta-irradiation, such as scleral necrosis, may arise more than 10 years after the irradiation. Longer follow-ups are necessary to reveal such
We performed primary pterygium excision...
We performed primary pterygium excision with intraoperative beta-irradiation in one eye of 6 patients between 1988 and 1990. 1000 rads of
beta-irradiation was applied to the scleral bed intraoperatively and one week
later. They were recently reviewed in our clinic for recurrence and
complications.(1) We also performed ultrasound biomicroscopic examination
(UBM) for both eyes in each patient, looking for corneal and scleral
thinning. Corneal thickness was arbitrarily measured 0.5 mm anterior to
the scleral spur at the 12, 3, 6, and 9 o'clock positions of each eye,
while the scleral thickness was measured 2 mm posterior to the scleral
spur at the same positions.
Mean follow-up was 138.0 months. Mean age at time of surgery was
37.5 years (range, 32 to 45 years). All 6 eyes were right eyes with nasal
pterygia in male patients. No recurrence was found, using the same
definition. There was neither significant deterioration in visual acuity
nor increase in intraocular pressure in any eye. There were no signs of
There were no significant differences in the scleral and corneal
thickness between the treated nasal position of the operated eye (mean
scleral, 0.617 +/- 0.112 mm; mean corneal, 0.656 +/- 0.076 mm) and the
control nasal position of the fellow eye (mean scleral, 0.611 +/- 0.030
mm; mean corneal, 0.645 +/- 0.044 mm).
Furthermore, there were no significant differences in the mean
scleral and corneal thickness between the operated eye (scleral, 0.590 +/-
0.077 mm; corneal, 0.635 +/- 0.067 mm) and the fellow eye (scleral, 0.590
+/- 0.059 mm; corneal, 0.624 +/- 0.054 mm). The mean scleral and corneal
thickness were calculated by averaging the scleral or corneal thickness at
the 4 measured positions in each eye.
It appears that beta-irradiation is safe, even in the long term. We
believe these additional data could supplement the findings by Amano et
1. Moriarty AP, Crawford GH, McAllister IL, et al. Severe corneoscleral
infection. A complication of beta scleral necrosis following pterygium
excision. Arch Ophthalmol 1993;111(7):947-51.