Corneal endothelial cell change after phacoemulsification relative to the severity of diabetic retinopathy

PURPOSE: To investigate the differences in corneal endothelial cell morphology between diabetic patients who were divided by the degree of the severity of diabetic retinopathy and normal patients after phacoemulsification with intraocular lens (IOL) implantation. SETTING: Department of Ophthalmology, College of Medicine, Pusan National University, Pusan, Korea. METHODS: Before and 6 months after phacoemulsification, specular microscopy was used to evaluate the number and morphology of endothelial cells in patients with diabetic retinopathy. The patients were divided into 3 groups: group I (n=30 eyes), without diabetes; group II (n=30 eyes), diabetes with severe nonproliferative diabetic retinopathy; group III (n=30 eyes), diabetes with high-risk proliferative diabetic retinopathy (PDR). RESULTS: Postoperative corneal endothelial cell density and hexagonality were significantly decreased and the coefficient of variation in cell size increased in all groups, in contrast to the preoperative state (P<.05). During the postoperative 6 months, the percentage of hexagonal cells showed a tendency to decrease progressively, and this was a significant difference between the 3 groups (P<.05). However, the patterns of change in endothelial cell density and the coefficient of variation in cell size were not different between the groups (P>.05). At the postoperative 6 months, the corneal endothelial cell density and the coefficient of variation in cell size of high-risk PDR patients were statistically changed compared with normal persons (P<.05). However, the percentage of hexagonal cell was not significantly difference between diabetic retinopathy patients and normal patients (P>.05). CONCLUSIONS: Corneal endothelial cell density significantly decreased and the coefficient of variation in cell size significantly increased for high-risk PDR patients undergoing phacoemulsification, in contrast to normal persons at the postoperative 6 months.     

Subperiosteal hematoma after surgical treatment for subarachnoid hemorrhage

After the surgical treatment for subarachnoid hemorrhage, computed tomography and magnetic resonance imaging clearly demonstrated a fracture in the medial wall of the left orbit and a superonasal subperiosteal hematoma. Removal of the subperiosteal hematoma and correction of the fracture were successful. Subperiosteal hematoma is an unusual complication after inadvertent neurosurgical manipulation.     

A comparative study for mesopic contrast sensitivity between photorefractive keratectomy and laser in situ keratomileusis.

BACKGROUND AND OBJECTIVE: To compare the effect on visual performance of photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) with mesopic contrast sensitivity. PATIENTS AND METHODS: Postoperative visual performance for 40 eyes undergoing PRK and 40 eyes undergoing LASIK was compared with mesopic contrast sensitivity at 1, 3, and 6 months postoperatively. Eyes were divided into two groups (< -6.0 D and > -6.25 D). Mesopic contrast sensitivity was performed with the patient's best-corrected visual acuity of 20/20 or better under photopic conditions. RESULTS: A significant decrease in mesopic contrast sensitivity from preoperative baseline was obtained at all spatial frequencies for the PRK and LASIK groups (P < .05). There was no statistically significant difference at 1 or 3 months postoperatively in both groups (P > .05). At 6 months postoperatively, LASIK significantly decreased mesopic contrast sensitivity more than PRK in myopia with a refractive error of less than -6.0 D, especially at the middle and high spatial frequencies of 6, 9, and 12 cycles per degree (P < .05). However, no statistically significant differences in mesopic contrast sensitivity between PRK and LASIK were found in myopia with a refractive error of greater than -6.25 D (P > .05). CONCLUSIONS: In broad-beam excimer laser refractive surgery, PRK seemed to have a more significant effect on mesopic contrast sensitivity than LASIK for myopia with a refractive error of less than -6.0 D at 6 months postoperatively.     

Normative measurements of Korean orbital structures revealed by computerized tomography

PURPOSE: The purposes of this study were to establish criteria for the diameters of normal extraocular muscles, the width of the optic nerve, and the globe position as revealed by CT, and to investigate the effects of age and sex on these parameters in the Korean population. SUBJECTS AND METHODS: Diameters of extraocular muscles (medial, lateral, superior complex, and inferior rectus), distance from the interzygomatic line to the posterior margin of the globe, width of the optic nerve-sheath complex, and length of the interzygomatic line were calculated for 214 patients on axial and direct coronal CT images, and the effects of age and sex were analyzed. RESULTS: Normal range for the diameters as given by mean+/-2SDs of extraocular muscles were medial rectus, 2.2--5.4 mm; lateral rectus, 2.1--4.9 mm; inferior rectus, 2.5--5.7 mm; and superior complex group, 2.6--6.4 mm. The mean optic nerve-sheath complex was 4.1 mm and the values ranged from 2.9 mm to 5.3 mm. The mean length of the interzygomatic line was 103.8 mm. The normal posterior position of the globe as here designed was 11.2 mm behind the interzygomatic line (range, 6.4--15.3 mm). All parameters under study were a little larger in males than females. Statistically, however, there was no significant difference between males' and females' results, nor between the various age groups (p>0.05). CONCLUSION: Our CT results may help clinical ophthalmologists to accurately assess enlargement of the extraocular muscles and the optic nerve as well as aiding in the evaluation of exophthalmos.     

Toxicity of indocyanine green injected into the subretinal space: subretinal toxicity of indocyanine green

PURPOSE: To evaluate the toxicity of indocyanine green (ICG) injected into the subretinal space. Indocyanine green may come in contact with photoreceptors and retinal pigment epithelium through a macular hole during ICG-assisted peeling of the internal limiting membrane. METHODS: Balanced salt solution or ICG of various concentrations (0.6, 1.25, 2.5, or 5.0 mg/mL) was injected into the subretinal space of rabbit eyes and removed after 1 minute. After 3 days, 1 week, and 4 weeks, the eyes were enucleated and evaluated by light microscopy and electron microscopy. RESULTS: When the ICG of 1.25 mg/mL or higher concentration was injected into the subretinal space, degenerative changes of the photoreceptors and the retinal pigment epithelial cells were found after 3 days with light and electron microscopy. After 1 week, the outer retina was disintegrated and the photoreceptors were not found. After 4 weeks in the eyes with 1.25 mg/mL ICG, short photoreceptors and a thin outer nuclear layer were seen. In the eyes with 2.5 mg/mL or higher ICG, the photoreceptors and the outer nuclear layer were destroyed completely. CONCLUSION: The results of this study suggest that the ICG of 1.25 mg/mL or higher concentration has toxicity to the outer retina of the rabbit and may cause adverse effects on the functional outcome after macular hole surgery.     

Intravitreal antibiotic therapy with vancomycin and aminoglycoside: examination of the retinal toxicity of repetitive injections after vitreous and lens surgery

The combination of vancomycin and an aminoglycoside antibiotic is frequently injected into aphakic/vitrectomized eyes for the treatment of endophthalmitis. At 2 weeks after lens and vitreous removal, rabbit eyes received an injection of a combination of 1 mg vancomycin and either 400 g amikacin or 100 g gentamicin. Furthermore, the effects of repeating the same combination a second and third time at intervals of 48 h were examined by light and transmission electron microscopy at 7 days to 4 months after the last injection. A single injection of either combination produced no toxicity. After 2 or 3 sets of injections of either combination, 13 of 16 eyes displayed retinal toxicity manifested by macrophages in the subretinal space, disorganization of the outer segments and retinal pigment epithelium, and discontinuities in Bruch's membrane. These results indicate that whereas a single injection of these combinations is not toxic to aphakic/vitrectomized eyes, repetitive injections may result in increasing toxicity.Presented at the XVIIth meeting of the Club Jules Gonin in Lausanne, Switzerland, in September 1990. This research was supported by National Eye Institute grant EY04474 and by the Lion's Eye Research Fund (D.J.D.)     

Childhood leukemia incidence in the vicinity of La Hague nuclear-waste reprocessing facility (France)

The incidence of leukemia is examined in young people (aged under 25 years) living within a 35 km radius of the French nuclear-waste reprocessing plant operating in La Hague, Normandy. During the period 1978–90, a total of 23 cases was diagnosed, giving an incidence rate of 2.99 per 100,000 which is close to the expected rate. In the canton in which the nuclear plant is located, three cases of leukemia were observed compared with 1.2 expected, giving a standardized incidence ratio of 2.5. This nonsignificant finding is compatible with no increased risk and also with a sevenfold excess risk. Therefore, it reinforces the necessity of conducting a case-control survey, which is now planned, to assess the part played by occupational radiation exposure in leukemia incidence for this French area.