Pressure sore in a patient who underwent repair of a retinal tear with gas injection

Purpose: To demonstrate a pressure sore following strict head positioning in a patient who underwent encircling band, vitrectomy and gas injection. Methods: A male patient was admitted to the hospital with a large posterior horseshoe tear in the inferior temporal retina with severe vitreous traction and retinal detachment. Encircling band, vitrectomy cryotherapy and gas injection was performed. After surgery the patient was instructed to sit in a facedown position. Results: A pressure sore resulted from prolonged immobility of the right elbow due to face-down positioning following encircling band, vitrectomy and gas injection. Conclusion: A patient injection. Conclusion: A patient may rarely have compulsive personality traits that result in extreme compliance to the physician's recommendations; therefore, general instructions given for head positioning should include permission for a change in position when required, at least for brief periods of time.     

Indocyanine green videoangiographic findings in choroidal metastatic tumor

Background: Indocyanine green videoangiography (ICGV) has recently advanced and become widely available as a clinical tool. We tested the efficacy of ICGV in evaluating metastatic choroidal tumors. Methods: ICGV using Topcon 50-IA was performed in five patients with clinically diagnosed choroidal metastatic tumors. The findings were compared with those of conventional fluorescein angiography (FAG). Results: Compared with FAG, ICGV demonstrated more smooth and regular hypofluorescent lesions, precisely indicating the exact size of the tumor. In all cases, no tumor vessels were found. The choroidal vascular integrity around the tumors was observed. FAG, however, was more sensitive in detecting the tumor development than ICGV when the extent of the hypofluorescent lesion could be seen clearly in the early phase. FAG provided more information regarding retinal pigment epithelial dysfunction in the outer blood retinal barrier overlying the tumor. Conclusion: Since ICGV enables visualization of tumors through the retina, it is very useful, particularly in cases of associated secondary retinal detachment around the tumors. ICGV combined with FAG provides more precise assessment of the tumors themselves and their response to treatment than FAG alone.     

The effect of nasolacrimal occlusion on drug-induced mydriasis

Background: Nasolacrimal occlusion has been shown to improve the efficacy of some topically applied ocular drugs. The aim of this study was to investigate the effect of nasolacrimal occlusion on tropicamide-induced mydriasis. Methods: We compared pupillary dilatation by 0.125% tropicamide with and without nasolacrimal occlusion in 40 healthy volunteers. Results: Analysis of variance with repeated measures failed to show any advantage due to nasolacrimal occlusion in drug-induced mydriasis. Conclusion: Nasolacrimal occlusion did not increase the mydriasis obtained with 0.125% tropicamide.     

Surgical risk factors for severe postoperative proliferative vitreoretinopathy (PVR) in retinal detachment with grade B PVR

Background: Previous studies have shown that grade B proliferative vitreoretinopathy (PVR) is a considerable risk factor for the development of severe postoperative PVR. We conducted a prospective study to elucidate which surgical procedures used in retinal detachment management may stimulate the PVR process in such eyes. Materials and methods: The study included 156 eyes of 152 consecutive patients with rhegmatogenous retinal detachment complicated by grade B PVR referred before any failed surgery and operated on between 1983 and 1993. The parameters evaluated by multivariate statistical analysis included the cumulative circumferential extent of the retinal tears, the extent of the scleral buckle, gas injection, vitrectomy, the method used for retinopexy, and the time of surgical management during the period of the study. Results: The incidence of severe postoperative PVR was 25.8% in eyes managed with cryotreatment versus 2.2% in eyes managed with argon laser photocoagulation (P=0.001). The rate of severe postoperative PVR was not influenced by the other surgical variables. Conclusion: We conclude that cryotherapy may be a risk factor for the development of severe postoperative PVR in retinal detachments associated with grade B PVR.     

A comparison of colour Doppler imaging of orbital vessels and other methods of blood flow assessment

Background: Comparison of the haemodynamic measurements obtained by colour Doppler imaging and other methods of ocular blood flow measurements was desired. Methods: The blood velocity findings from colour Doppler imaging of patients with central retinal vein occlusion were compared to the results of fluorescein video-angiography, continuous tonography and ophthalmodynamometry. Results: Patients with low or undetectable blood velocities in the central retinal vein had longer retinal dye transit times on fluorescein video-angiography. Tonography showed a positive correlation with the velocities in the ophthalmic artery, but ophthalmo-dynamometry showed a negative correlation with these velocities. Conclusion: The relationships between the blood velocities in orbital vessels and other blood flow measurements emphasise that there is a complex interaction of the blood flow parameters. Care must therefore be taken when interpreting the results of studies.     

Effects of norfloxacin on the retina in rabbits

Background: Fluoroquinolones have a strong affinity with melanin, and their ocular effects have been reevaluated. Norfloxacin, one of the fluoroquinolones, has broad-spectrum activity against aerobic gram-positive and gram-negative bacteria. We examined the retinal toxicity and intraocular pharmacokinetics of intravitreal norfloxacin in rabbits. Methods: Twenty-three albino and 23 pigmented rabbits were divided into three groups to evaluate retinal toxicity and two groups to investigate the intraocular pharmacokinetics. Each of these five groups was further divided into two subgroups (albino rabbits and pigmented rabbits). Results: With 500 Etg norfloxacin, the oscillatory potential of the electroretinogram was transiently and selectively deteriorated in albino and pigmented rabbits, whereas the electroretinogram remained unchanged with 50 g in pigmented rabbits. No changes were observed in the visual evoked potential or on histology of the retina 7 days after an intravitreal injection of 50 or 500 ltg norfloxacin. The electroretinogram and the retinal histology became abnormal 7 days after four intravitreal injections of 500 g norfloxacin at 7-day intervals. As regards the intraocular pharmacokinetics after an intravitreal injection, the norfloxacin concentration in the chorioretina was as high as that in the vitreous 3 h after injection and was much higher than that in the vitreous 7 days after injection. Similar results were obtained after multiple injections. Conclusion: These results indicate a high concentration of norfloxacin in the melanin-containing ocular tissues.     

Unusual retinal pigment epitheliopathy and choroidopathy in carcinomatosis: A rare case of cancer-associated retinopathy

Background: Cancer-associated retinopathy is a syndrome causing ocular symptoms. It is a rare entity and only a few cases have been reported. Methods: A 67-year-old woman with small-cell endometrial carcinoma suffering from deterioration of visual acuity is presented. Results: The patient presented with extensive mottled changes of the retinal pigment epithelium, accompanied by diffuse subretinal fluid in the posterior pole and exudative retinal detachments inferior in both eyes. Conclusion: This patient suffered from a rare variety of cancer-associated retinopathy.     

Therapeutic pars plana vitrectomy for chronic uveitis: a retrospective study of the long-term results

Background: Pars plana vitrectomy has both diagnostic and therapeutic potential in chronic uveitis. In this paper the therapeutic value of vitrectomy is investigated. Methods: This is a retrospective study on 25 eyes that underwent pars plana vitrectomy with therapeutic intent. Surgery was considered in patients with severe vitreous clouding or macular pucker and in those who responded poorly or not at all to conventional treatment for uveitis. The mean period of follow up was 4.5 years, varying from 2 to 12 years. Results: Improved vision was observed in 56% of the eyes (14/25). Twenty-four percent of the eyes (6/ 25) had stable vision. Macular edema disappeared in 40% (10/25) of cases and persisted in 60% (15/25). Two of the nine eyes with persistent macular oedema progressed to a macular hole. Four of the six eyes with macular pucker suffered recurrence, one ended in phythisis, while the pucker was cured in only one patient. Twelve percent of the eyes (3/25) subsequently experienced a recrudescence of uveitis, making systemic treatment necessary. One patient presented, after vitrectomy, a traction retinal detachment with proliferating vitreoretinopathy. No complications or recurrences were seen in 44% of the eyes (11/25). Conclusion: Vitrectomy has a definite place in the treatment of chronic uveitis, both on the functional level, with improvement or stabilisation of visual acuity and on the therapeutic level, with possible reduction or cessation of systemic treatment.     

Anterior chamber inflammation after transconjunctival cryosurgery

Background: Inflammation caused by transconjunctival cryotherapy for prophylactic retinal detachment surgery was measured in various conditions. Methods: Thirty-four eyes of 28 patients with peripheral retinal lesions predisposing to retinal detachment were studied by laser flare cell meter before and after treatment. Results: The mean flare value for 34 eyes was 4.06 ± 1.45 photon counts/ms before surgery and 5.72 ± 2.52 pc/ms after surgery (p < 0.05). Flare value was elevated at 1, 2, and 3 weeks after treatment, peaking at 2 weeks (p < 0.05), and normal again at 4 weeks. There were no significant differences in flare increase between eyes with and without retinal breaks, eyes with and without limited retinal detachment, eyes with myopia more and less than – 8.0 D, and eyes with a treatment area limited to one quadrant and extending over more than one quadrant. Conclusion: Transconjunctival cryosurgery caused mild inflammation in the anterior chamber of the eye for 3 weeks. The inflammation was not affected by the presence of retinal break or limited retinal detachment, the degree of myopia, or the extent of the treatment area.     

Pars plana vitrectomy for retinal detachment due to internal posterior ophthalmomyiasis after cataract extraction

Background: The authors report a case of posterior internal ophthalmomyiasis causing vitreous haemorrhage and retinal detachment after uncomplicated cataract extration. Case report: The patient suffered an abrupt vitreous haemorrhage 9 days after ECCE and posterior chamber IOL implantation. After 2 months the haemorrhage did not clear up and a retinal detachment arose. The patient underwent encircling scleral buckle, pars plana vitrectomy and fluid-gas exchange. In course of intervention the surgeon removed from the vitreous chamber a 14-mm-long round worm subsequently identified as a dipterous larva of the Sarcophagidae family. Discussion: The patient showed no sign of subretinal tracking or retinal breaks or holes. The sclerocorneal surgical wound seems the most likely site of entrance of the parasite, and this would then be the first reported case of myiasis with no RPE tracking.     

Communication between the subretinal space and the vitreous cavity in the morning glory syndrome

Background: The aim was to describe a pathogenic mechanism for a rhegmatogenous retinal detachment in a 69-year-old man with the morning glory syndrome. Methods: During vitreous surgery for a retinal detachment, a membrane was removed that covered the optic disc anomaly and produced traction on the peripapillary retina. A retinal hole was found in tissue lying within the optic cup, and the hole was sealed using a autologous plasma —thrombin mixture. Silicone oil was used for retinal tamponade. Results: A retinal hole in tissue lying within the optic cup provided a fluid pathway between the vitreous cavity and the subretinal space. Following vitrectomy surgery, bubbles of silicone oil passed through the retinal hole into the subretinal space of the macula. Conclusion: This case demonstrates that a retinal hole in tissue lying within the optic disc anomaly of the morning glory syndrome provides a communication for fluid between the subretinal space and the vitreous cavity, resulting in a rhegmatogenous retinal detachment. Vitreous replacement with silicone oil resulted in the migration of silicone bubbles into the subretinal space.     

Effect of oxygen on relaxation of retinal pericytes by sodium nitroprusside

Background: This study addresses whether oxygen modulates the relaxation induced in retinal pericytes by sodium nitroprusside (SNP), a nitric oxide (NO) donor that stimulates the NO/guanylate cyclase pathway. Methods:Bovine retinal pericytes were cultured on silicone. On the silicone surface, basal pericyte contractile tone induces wrinkles. Drug-induced changes in pericyte contractile tone were assessed by changes in the number of wrinkles. The effects of 100% nitrogen (hypoxia) and 100% oxygen (hyperoxia) were studied on: (a) the basal tone of quiescent pericytes, (b) the relaxation to 3 and 10 M SNP or 1 M forskolin, and (c) the recontraction that followed the washout of 3 M SNP or 1 M forskolin. Results: Neither hypoxia nor hyperoxia had any apparent influence on pericyte basal tone, on forskolin-induced relaxation, or on pericyte recontraction after a forskolin-induced relaxation. In hypoxia, relaxations to SNP 3 M (P<0.05) and 10 M (P<0.01) were significantly more pronounced than in hyperoxia. Hypoxia also reduced the recontraction after an SNP-induced relaxation (P<0.001). Conclusion: Oxygen modulates the relaxation of bovine retinal pericytes evoked by SNP (guanylate cyclase-mediated), but not the relaxation induced by forskolin (adenylate cyclase-mediated). These results suggest that in the retinal capillary circulation an interaction between oxygen and the NO/guanylate cyclase pathway modulates pericyte tone, and thus potentially blood flow.     

Exotropia secondary to vitreous hemorrhage

Background: Diplopia after cataract surgery has been reported by several authors, but diplopia after recovery from vitreous hemorrhage (VH) has not been described. Methods: We examined eight patients with manifest exotropia and binocular diplopia after recovery from dense VH by vitreous surgery. VH was bilateral in three patients and unilateral in five, and lasted for an average of 7.7 years. Results: Visual acuity before vitrectomy ranged from 20/200 to light perception; that after vitrectomy ranged from 20/20 to 20/60. Exotropia was present in all patients after vitrectomy. Additionally, seven out of eight patients had vertical strabismus with an average deviation of 6 prism diopters (). Fusion was confirmed in four patients with an average amplitude of 13 . Four patients underwent horizontal strabismus surgery. Fusion was present in two before strabismus surgery and in all four after surgery; however, unstable diplopia persisted in three of the four after surgery. Conclusion: Diplopia after vitrectomy for longstanding VH may occur due to fusion impairment comparable to that occasionally seen after surgery for traumatic cataract.     

Interpretation of high-pass resolution perimetry with a probability plot

Background: The interpretation of high-pass resolution perimetry (HRP) fields can be difficult. An age-related probability plot was derived from a known data base to determine whether this improved specificity and sensitivity in early glaucoma detection Methods: Forty glaucoma patients with minor field loss and 40 normals of equivalent age and sex underwent HRP. All had previous Humphrey field data available for comparison. The detection of previously confirmed field defects by HRP was examined using different parameters. Results: Using the age-corrected 95% confidence levels gave the best results, with sensitivity of 82.5% (33/40) and specificity of 85% (34/40). Using the contour plot yielded lower sensitivity (67.5%), while subjectively eyeballing the ring printout gave higher sensitivity (90%), but led to poor specificity (72.5%). Conclusion: The use of a probability plot enhances the performance of HRP. A certain proportion of cases may be missed using one criterion alone, but combining the information with other indices can increase the yield.The authors have no proprietary interest in the equipment and technique described herein     

Isovolemic hemodilution increases retinal tissue oxygen tension

Background: Therapeutic isovolemic hemodilution has been reported to improve blood flow and oxygen delivery. Few reliable measurements have been made, however, showing the effect of hemodilution on tissue oxygen tension. Methods: We measured retinal oxygen tension during experimental isovolemic hemodilution in normal cats. Polarographic oxygen microelectrodes were placed in the vitreous humor within 100–200 m of the retinal surface.Results: Tissue oxygen tension increased initially during isovolemic hemodilution to a maximum approximately 50% above baseline at approximately two thirds of the original hematocrit level. Hemodilution beyond this point to lower hematocrits caused a steady decline in tissue oxygen tension. Cardiac output measured in one cat undergoing isovolemic hemodilution increased as hematocrit was lowered, but the cardiac erythrocyte flux actually decreased steadily.Conclusion: The observed increase in tissue oxygen tension with hemodilution appears to be explained by a lesser reduction in capillary than in systemic hematocrit, coupled with an increased capillary blood flow. The increase in tissue oxygen tension we observed could in part explain the clinically beneficial effects of hemodilution.     

The retinal depression sign in diabetic retinopathy

Background: The retinal depression sign, an abnormal light reflex due to ischemia-induced focal inner retinal atrophy, was initially described in patients with sickle cell retinopathy. We undertook this study to characterize the finding in diabetic retinopathy. Methods: The fundus photographs of 97 consecutive patients with diabetic retinopathy seen in the Penn State University Ophthalmology Department were reviewed. We recorded age, sex, type of retinopathy, visual acuity and photographic details, including the presence or absence of the retinal depression halo. Results: The retinal depression sign was present in 9 of 22 patients age 45 years or under, versus 1 of 75 patients age 46 or older (P<0.0001, two-tailed Fisher's exact test). The presence or absence of retinal depression sign did not predict the type of retinopathy in a given patient. Eleven (70%) of the affected eyes had visual acuity 20/40. Conclusion: The retinal depression sign is common in younger patients with diabetes and should be distinguished from other macular lesions associated with diabetic retinopathy.     

The effect of chemical stability and purification of perfluorocarbon liquids in experimental extended-term vitreous substitution

Background: To determine the importance of chemical stability and purification of perfluorocarbon liquids (PFCLs) in experimental retinal tolerance, we tested four different substances as long-term vitreous tamponade: purified and nonpurified perfluorodecalin (PFD) and perfluoro-octylbromide (PFOB) Method: After mechanical vitrectomy we replaced the vitreous of 65 rabbit eyes. Five groups were formed; four of them received the four PFCLs, while one served as control and received Ringer solution. The eyes were observed clinically every week and examined histologically after 1, 2, 4 and 8 weeks Results: After 1 week we observed foam cells and intraretinal macrophages in all eyes with PFCLs. Purified PFD caused retinal lesions in the photoreceptor, ganglion cell and outer nuclear layers after only 2 weeks in the lower part of the eyes. In eyes filled with purified PFOB we observed more pronounced damage of the same nature. Unpurified substances caused severe inflammation and retinal detachment Conclusion: Our study demonstrates that purification and chemical stability are important factors in retinal tolerance of PFCLs for vitreous replacement. Although purified PFD was tolerated by the rabbit eyes for 1 week, we cannot recommend this substance for short-term clinical use as a vitreous substitute.     

The effect of high-dose methylprednisolone on laser-induced retinal injury in primates: an electron microscopic study

Background: Previously we reported an ameliorative effect of high-dose methylprednisolone in laser injury to monkey retinas. The ultrastructural modification by methylprednisolone has not been examined. Methods: Cynomolgus monkeys were given severe kgrade III) retinal laser burns and treated with an intravenous megadose of methylprednisolone. Pathologic features of the retinal lesions with or without methylprednisolone treatment were evaluated by light and electron microscopy. Results: Ultrastructurally, the treated lesions showed rapid recanalization of choriocapillaris; proliferation of retinal pigment epithelium to replace the necrotic and damaged cells, resulting in rapid re-establishment of blood retinal barrier; mild macrophagic activity; and rapid reformation of the outer limiting membrane by Mueller cells. Conclusion: A high dose of methylprednisolone affected the responses of the choriocapillaris, retinal pigment epithelium, photoreceptor cells and Mueller cells to laser injury, showing an overall beneficial effect. These modifications might be ascribed to methylprednisclone's anti-inflammatory action, protection of the microcirculation and anti-lipid peroxidation effect. Proprietary interest: none     

The role of inner wall retinectomy in the management of juvenile retinoschisis

Purpose: The purpose of this paper is to describe the technique and application of relief of vitreous traction and inner wall retinectomy in the management of juvenile retinoschisis (JRS). In addition, during the course of this study a previously undescribed form of tractional retinal detachment associated with retinal schisis was observed. Methods: Six eyes of four children with visual field and/or central vision loss underwent vitrectomy (in five of the six eyes the lenses were preserved), inner wall retinectomy and photocoagulation for rhegmatogenous/schisis retinal detachment, tractional retinal detachment and reduced central vision secondary to intraschisis hemorrhage overhanging the macula. Results: The children were followed up for 1 to 4 years. All eyes showed anatomic reattachment. Three of the four eyes that could be tested for vision showed improved visual function postoperatively. One eye showed marked enlargement of visual field and central visual acuity improvement from 20/200 preoperatively to 20/50 postoperatively. Conclusion: Inner wall retinectomy can be a useful adjunct in the management of the retinal complication of JRS. Appropriate case selection of eyes with associated central traction retinal detachment can result in improved visual field and central visual acuity. The success of this technique suggests that the mechanical and/or pharmacological relief of vitreous traction may be able to alter the clinical course of JRS.     

Reattachment to a substrate prevents apoptosis of human retinal pigment epithelium

Background: Epithelial cells generally fail to survive in suspension. Harvesting human retinal pigment epithelium (RPE) for transplantation may separate the cells from their extracellular matrix and induce apoptosis. We investigated whether reattachment of RPE to a substrate will prevent apoptosis. Methods: Second-passage human RPE cells were plated onto tissue culture plastic precoated with extracellular matrix, fibronectin or laminin, uncoated tissue culture plastic, untreated plastic and untreated plastic coated with 4% agarose. Reattachment rates were determined for each substrate 24 h after plating. The TUNEL technique was used to determine apoptosis rates in attached cells, unattached cells and the entire cell population. Results: Attachment rates were as follows: ECM-coated tissue culture plastic fibronectin-coated tissue culture plastic laminin-coated tissue culture plastic uncoated tissue culture plastic untreated plastic agarose-coated untreated plastic. Apoptosis rates for the entire cell population increased as the RPE cell attachment rate decreased. The proportion of apoptotic cells in the entire population was inversely related to the percent attached cells (r = -0.95). Conclusion: Reattachment of harvested RPE to a substrate decreased the rate of RPE apoptosisin vitro. RPE cells which are removed from their substrate prior to transplantation must reattach rapidly to a substrate to prevent apoptosis.Presented in part at the Annual Meeting of the Association for Research in Vision and Ophthalmology, Fort Lauderdale, Florida, May 1996