Anterior chamber fixation of a posterior chamber intraocular lens: a novel technique.

We aimed to evaluate the implantation of a posterior chamber intraocular lens (IOL) in the anterior chamber (AC) with the haptics passing through two iridectomies to the posterior chamber. A total of 33 eyes of 33 patients with inadequate posterior capsular support due to either previous aphakia or posterior capsular rupture during cataract extraction were included in the study. A double iridectomy was performed on all patients using a vitrectomy probe on the midperiphery of the iris. IOLs were implanted in the AC, and the haptics were passed through the iridectomies to the posterior chamber. The mean follow-up time was 25.3 months. AC hemorrhage occurred in five patients during the iridectomy procedure. Corneal edema was detected in eight of 14 patients with primary IOL insertions. Haptic dislocation was detected in only one patient. This technique may be a good alternative to scleral-fixated IOL implantation in eyes with aphakia.

Characteristics of pellet injuries to the orbit.

PURPOSE: To investigate the features of orbital injuries by pellets fired from the front. DESIGN: Retrospective, 4 cases of pellet injuries. METHODS: Five orbits of 4 patients who sustained pellet injuries received from the front were reviewed retrospectively. The course of injury and results were assessed. Radiological examinations were reviewed. The patients were evaluated between December 1996 and June 2004. RESULTS: Five orbits of 4 patients sustained injuries caused by pellets fired from an anterior direction. The globe in the injured orbit was intact in 2 cases. Severe loss of vision was also present in these 2 globes due to optic nerve involvement. Final visual acuity was down to no light perception in 4 eyes and limited to light perception in 1 eye. CONCLUSIONS: The prognosis of orbital pellet injuries is, unfortunately, poor. A pellet passing through the floor of the orbit often causes double perforation of the globe and, once in the orbital aperture, it travels towards the apex as a result of the conical shape of the orbit and lodges in the optic canal or its entrance, severely damaging the optic nerve. Surgery or other treatments are usually unsuccessful. Even if the globe is intact, vision is usually severely impaired.

Protective role of alpha-tocopherol on retinal injury in experimental uveitis in guinea pigs.

PURPOSE: PURPOSEof the study was to determine whether alpha-tocopherol (AT) can protect the retina from oxidative damage in experimental uveitis (EU). MATERIAL AND METHODS: The eyes of 36 adult male guinea pigs were studied. The guinea pigs were divided into three groups of 12 animals each. The first group was used as control. The right eyes of groups 2 and 3 received an intravitreal injection of bovine serum albumin for EU induction. At the same time and also on the consecutive third and fifth days, group 3 received intraperitoneal AT injections. The samples were collected on the eighth day. Retinal malondialdehyde (MDA) levels and the average thickness of the inner plexiform layer were measured and the histopathology of the eyes was studied. RESULTS: The MDA level was significantly lower in the control group than in the groups 2 (p<0.01) and 3 (p<0.05). When compared with the EU group 2, there was a significant lowering of MDA in the AT injected group 3 (p<0.01). The thickness of the inner plexiform layer in the control group 1 was significantly lower than in the other groups (p<0.01). Its thickness in the group 3 supplied with AT was significantly lower than in the group 2 (p<0.01). CONCLUSIONS: The data indicate that intraperitoneal AT administration protects against EU injury in the guinea pig retina as evidenced by the reduced MDA and the thickness of retina.

Effects of intraperitoneal vitamin E, melatonin and aprotinin on leptin expression in the guinea pig eye during experimental uveitis.

PURPOSE: To observe ultrastructural changes and leptin expression in the guinea pig eye during experimental uveitis (EU) and the effects of vitamin E, melatonin and aprotinin on leptin expression. METHODS: Thirty male guinea pigs were randomly classified into five groups. Group 1 was the control group. Groups 2, 3, 4 and 5 received intravitreal injections of bovine serum albumin (BSA) to induce EU. At the same time on the third day, groups 3 (EU + vitamin E), 4 (EU + melatonin) and 5 (EU + aprotinin) received intraperitoneal vitamin E (150 mg/kg), melatonin (10 mg/kg) and aprotinin (20,000 IU/kg), respectively. On the sixth day, histopathological and clinical scoring of inflammation were performed, and leptin expression was investigated in the retina, choroid, sclera, episclera and cornea, and compared. RESULTS: There was a remarkable increase in leptin expression in the retina, choroid, sclera and episclera in the EU group. Leptin expression in the treatment groups was similar to that in the control group. At light and electron microscopic levels, ganglion cells were oedematous and inner plexiform layer thickness had increased in the EU group retinas. Oedema was decreased in the treatment groups. Comparison of the EU and treatment groups revealed significant differences histopathologically and clinically. CONCLUSION: Experimental uveitis causes an increase in leptin expression in the retina, choroid, sclera and episclera of guinea pigs. Vitamin E, melatonin and aprotinin inhibit this increase. Leptin seems to be closely related to ocular inflammation.

Leptin in corneas from keratoconus and infectious keratitis patients.

PURPOSE: Leptin is produced primarily by adipose tissue. More recent studies have shown extra sites of leptin production in physiologic and ill human tissues. However, whether leptin originates from human corneas in infectious keratitis and keratoconus is not known. The aim of this study was to demonstrate and quantitate leptin expression in corneas with infectious keratitis and keratoconus and make comparisons to control corneas. METHODS: We examined the immunohistochemical staining of leptin in nine corneas surgically excised from patients with infectious keratitis (3 patients), keratoconus (3 patients), and donor corneas (3 patients). RESULTS: The results were analyzed using a semiquantitative scoring system of mild, moderate, and strong. Cells of the infectious keratitis group had the strongest leptin staining intensity, the control group had moderate, and the keratoconus group had mild staining intensity. The more vascular corneas in the infectious keratitis group were also associated with the greatest leptin staining. CONCLUSIONS: Our findings indicate that leptin expression was present in all three sources of corneas (infectious keratitis, keratoconus, and normal control). Quantitative scoring would imply it may play a role in infectious keratitis, although further experiments are necessary to establish any causal relationship.

Antioxidant effects of alpha-, gamma- and succinate-tocopherols in guinea pig retina during ischemia-reperfusion injury.

The purpose of this study is to investigate the efficacy of alpha-tocopherol (AT), gamma-tocopherol (GT) and d-alpha-tocopherol polyethylene glycol 1000 succinate (TPGS) in preventing the retinal injury followed by ischemia-reperfusion (IR). The eyes of 40 adult male guinea pigs were used in the study. The guinea pigs were divided into five groups of eight rats each. First and second groups were used as control and IR groups, respectively. Third, fourth and fifth groups received subcutaneously AT, GT and TPGS, respectively. Treatment with each vitamin was performed before 5min of ischemia with reperfusion at 6h intervals for three times. Retinal ischemia was induced for 90min, then followed by reperfusion for 24h. The animals were killed at 24h of reperfusion. Lipid peroxidation (LP) and glutathione (GSH) levels were measured in right retinas by using a spectrofluorometer. Retinal GSH levels were found significantly lower (p < 0.002) in the IR group than in control group and there was a significant increase in the LP levels in IR group (p < 0.001). The decrease of GSH and increase of LP levels in the IR animals were significantly (p < 0.05 and 0.001) improved by the administration of the Vitamin E forms. When compared to GT group, there were no significant differences in LP levels in AT and TPGS groups. However, LP level in AT group was significantly (p < 0.01) lower than in the TPGS group. The GSH levels were higher (p < 0.001) in AT and TPGS groups than in IR group. Therefore, modulator effect of AT and GT were greater than that of TPGS. In conclusion, present data demonstrate that there is an increase in the LP in the retina of IR-induced animals and a decrease in the GSH levels. However, subcutaneous AT, GT and TPGS were effective in preventing retinal injury followed by ischemia-reperfusion. The subcutaneous AT may play a role in treating IR injury.

Administration of high dose intravitreal melatonin degenerates retinal cells in guinea pigs.

The purpose of this study was to investigate the influence of intravitreally injected different doses of melatonin on retinal morphology. The right eyes of 35 male albino guinea pigs were used. The animals were classified randomly into five groups in equal numbers. First group was used as control and received intravitreal injection of placebo. Groups 2, 3, 4 and 5 received intravitreally injections of melatonin at 50, 100, 150 and 200microg/body weight (BW) each, respectively. The animals were sacrificed 15 days after the injections. The eyes were enucleated and processed for light microscopic evaluation. Intravitreal injection of melatonin at doses ranging from 50 to 150microg did not induce morphological changes, although a higher thickness of the inner plexiform layer (IPL) was found in Group 5 compared to other groups (p < 0.05). The mean retinal ganglion cell (RGC) counts were found to be lower in Group 5 compared to other groups (p < 0.05). Our findings indicate that intravitreal injection of melatonin at doses ranging from 50 to 150microg/BW does not induce morphological changes. The dose of 200microg/BW produced significant damage including retinal ganglion cell loss and formation of retinal edema.

Protective effects of intraperitoneal vitamin C, aprotinin and melatonin administration on retinal edema during experimental uveitis in the guinea pig.

A considerable amount of clinical and experimental evidence exists suggesting the involvement of reactive oxygen substances (ROS) in the aetiology of uveitis. The activated phagocytic system of polymorphonuclear leucocytes in uveitis is involved in the generation of ROS. In addition to their direct free radical scavenging action, aprotinin, melatonin and vitamin C are known to protect against oedema formation and can preserve plasma membrane fluidity and free radical production. Histological changes in the retina that occur during uveitis are not well explained. The purpose of this study was to determine whether vitamin C, aprotinin and melatonin can protect the retina from damage accompanying experimental uveitis (EU). Thirty adult male guinea pigs were divided into five groups of six animals each. The first group was used as control. The right eyes of groups 2, 3, 4 and 5 received an intravitreal injection of bovine serum albumin for induction of experimental uveitis. At the same time and also on the consecutive third day, groups 3, 4 and 5 received intraperitoneal injections of vitamin C (ascorbic acid, 100 mg kg(-1) body wt), aprotinin (20,000 kIU kg(-1) body wt) and melatonin (10 mg kg(-1) body wt), respectively. The animals were killed on the sixth day. The average thickness of the retina and inner plexiform layer for each eye was measured in sagittal section near the optic nerve and expressed in microns. The thickness of the retina and inner plexiform layer in the control group was significantly (p < 0.01) lower than in the group EU as compared with the group EU plus vitamin C, group EU plus aprotinin, group EU plus melatonin (p < 0.05). The thicknesses of the retina and inner plexiform layer in group EU plus vitamin C, group EU plus aprotinin and group EU plus melatonin were significantly (p < 0.01) lower than that in the group EU. The difference in thickness of the retina and inner plexiform layer among the groups 3, 4 and 5 was not significant (p > 0.05). In conclusion, this study demonstrated that oedematous effects of EU on the retina were reduced by the administration of intraperitoneal vitamin C, aprotinin and melatonin, i.e. these antioxidants had significant protective effects on the retina of guinea pigs against oedematous damage in EU. However, the reductive effect of vitamin C on EU was greater than that of aprotinin and melatonin. The intraperitoneal vitamin C, aprotinin and melatonin supplementations may strengthen the antioxidant defence system because of decreased ROS, and these agents may play a role in treating uveitis.

Protective effects of vitamin E forms (alpha-tocopherol, gamma-tocopherol and d-alpha-tocopherol polyethylene glycol 1000 succinate) on retinal edema during ischemia-reperfusion injury in the guinea pig retina.

PURPOSE: The purpose of this study is to provide evidence that free radical damage is a component of retinal ischemia-reperfusion (I/R) injury, and to determine whether alpha-tocopherol, gamma-tocopherol and d-alpha-tocopherol polyethylene glycol 1000 succinate (TPGS) can protect the retina from this injury. METHODS: The right eyes of 40 male guinea pigs weighing 500-600 g were used. The animals were randomly assigned to group 1 (control), group 2 (I/R), group 3 (I/R plus alpha-tocopherol), group 4 (I/R plus gamma-tocopherol) and group 5 (I/R plus TPGS). Groups 3, 4 and 5 received four subcutaneous injections at six-hour intervals for total dosage of 800 IU/kg alpha-tocopherol, 1000 IU/kg gamma-tocopherol and 750 IU/kg TPGS, respectively. The first dose of each substance was administered 5 minutes before retinal ischemia. Retinal ischemia was induced for 90 minutes, then followed by reperfusion for 24 hours. Injections of three substances were repeated at 6, 12 and 18 hours during reperfusion. The animals were killed at 24 hours of reperfusion. Sagittal sections of 4 microm were cut and stained with hematoxylin and eosin for light microscopic evaluation. The average thickness (edema) of the inner plexiform layer for each eye was measured in sagittal sections near the optic nerve and expressed in microns. RESULTS: All the three substances showed statistically significant protection against the formation of retinal edema during ischemia-reperfusion injury. The mean thickness of the inner plexiform layer were 15.0, 25.44, 19.81, 21.38 and 20.88 microm in control, I/R, I/R plus alpha-tocopherol, I/R plus gamma-tocopherol and I/R plus TPGS groups, respectively. The results showed that the thickness of the inner plexiform layer in group 1 (control) was significantly lower than the other groups (p<0.001). The inner plexiform layer was thicker in the I/R group than with I/R plus alpha-tocopherol (p<0.001), I/R plus gamma-tocopherol (p<0.001) and I/R plus TPGS (p<0.01). The inner plexiform layer was not thicker in the I/R plus TPGS group than in the I/R plus alpha-tocopherol and I/R plus gamma-tocopherol groups. Compared to the I/R plus alpha-tocopherol group, the inner plexiform layer was significantly thicker in the I/R plus gamma-tocopherol group (p<0.01). CONCLUSIONS: The results from these experiments indicate that vitamin E forms have protective effects on the retina during retinal ischemia-reperfusion injury, but, the effects of alpha-tocopherol and TPGS appear to be much greater than that of gamma-tocopherol.

Pigmented paravenous retinochoroidal atrophy. A literature review supported by seven cases.

Seven patients (4 men and 3 women, ranging in age from 27 to 64 years) with pigmented paravenous retinochoroidal atrophy, a rare disorder of unknown origin, were studied. The mean follow-up time was 18.5 months. Fundus examinations were performed, and color fundus photographs were taken. In addition to fluorescein angiography, visual field examinations, color vision and electroretinographic tests were performed. All 7 patients were asymptomatic, with visual acuities ranging from 3/10 to 10/10. Both fundi showed patches of retinochoroidal atrophy and pigmentation along the retinal veins in all patients. Fluorescein angiography showed hyperfluorescence due to the pigment epithelial atrophy together with hypofluorescence corresponding to bone spicule pigment clumping. Visual field tests showed scotomas corresponding with areas of atrophy along the retinal veins. The electroretinography showed reduced responses in 2 cases. Color vision was normal in all cases. The patients had no history of trauma or a previous inflammatory process. Serology for syphilis, Toxoplasma and cytomegalovirus as well as a skin test for tuberculosis were negative. When the patients were seen at the end of the follow-up period, no variation of the findings was noted. Although the fundus abnormalities can be mild or severe, retinal function tests indicated that this is a geographic and not a generalized disorder.

Effects of melatonin, vitamin E and octreotide on lipid peroxidation during ischemia-reperfusion in the guinea pig retina.

PURPOSE: The purpose of this study is to provide evidence that free radical damage is a component of retinal ischemia-reperfusion (I/R) injury, and to determine whether melatonin, vitamin E and octreotide can protect the retina from this injury. METHODS: The right eyes of 50 male guinea pigs weighing 500-600 g were used. The animals were randomly assigned to group 1 (control), group 2 (I/R), group 3 (melatonin + I/R), group 4 (vitamin E + I/R) and group 5 (octreotide + I/R). Groups 3, 4 and 5 received four subcutaneous injections with a 6-h interval for a total daily dose of 10 mg/kg melatonin, 150 mg/kg vitamin E and 22 microg/kg octreotide. The first dose of each substance was administered 5 minutes before retinal ischemia, which was induced for 1.5 hours, followed by reperfusion for 24 hours. All three substances were repeated for 6, 12 and 18 hours during reperfusion. The animals were killed at 24 hours of reperfusion. Retinas were isolated and processed for the quantification of malondialdehyde (MDA). RESULTS: The compounds had the following relationships: melatonin more than vitamin E more than octreotide in preventing retinal damage by ischemia-reperfusion. All three gave significantprotection against the formation of MDA (10.4+/-2.3, 12.4+/-2.4, 13.9+/-1.5 nmol/100 mg tissue wet weight, respectively) compared to the control (3.7+/-1.3 nmol/100 mg tissue wet weight) and I/R groups (22.7+/-6.2 nmol/100 mg tissue wet weight). CONCLUSIONS: This study demonstrates the inhibitory effect of melatonin, vitamin E and octreotide on MDA levels during retinal ischemia-reperfusion injury.