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.     

Preoperative vitreous hemorrhage associated with rhegmatogenous retinal detachment: a risk factor for postoperative proliferative vitreoretinopathy?

Background: We conducted a prospective clinical study to elucidate the role of preoperative vitreous hemorrhage in the development of postoperative proliferative vitreoretinopathy (PVR) in primary rhegmatogenous retinal detachment. Materials and methods: We prospectively evaluated 409 eyes of 390 patients affected by primary rhegmatogenous retinal detachment referred before any failed attempt to reattach the retina. Single and multiple logistic regression analysis were used to test 14 categories of variables. Results: Postoperative PVR occurred in 48 (11.7% of 409 eyes). Postoperative PVR developed in 41 (11.8%) of the 347 eyes with no preoperative vitreous hemorrhage, and 7 (11.3%) of the 62 eyes with preoperative vitreous hemorrhage (P=0.90). The results of multiple logistic regression analysis showed that only four variables were significant factors which had independently and jointly an effect on the risk of postoperative PVR: (1) 90° or greater circumferential extent of the retinal tears; (2) preoperative PVR grade B; (3) preoperative PVR grade C-D; and (4) the use of cyrotreatment as the method of retinopexy. Conclusion: With the surgical techniques currently used, mild preoperative vitreous hemorrhage is not an independent risk factor for postoperative PVR in primary rhegmatogenous retinal detachment. The role of moderate and severe vitreous hemorrhage remains to be fully evaluated in a larger series of eyes.     

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.     

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.     

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.     

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.     

Aqueous flare in eyes with senile disciform macular degeneration: correlation with clinical stage and area of neovascular membrane

Background: The aim of the present study was to investigate the aqueous flare in eyes with senile disciform macular degeneration (SDMD), divided into different clinical stages, and the correlation between the aqueous flare and the area of the neovascular membrane. Methods: Eighty-six eyes of 44 patients with SDMD were examined using a laser flare meter. The area of the neovascular membrane was measured by means of a digitizer in images obtained using indocyanine green videoangiography. Results: The mean value of the aqueous flare was 5.91±2.51 (photon count/ms) in 7 predisposing stage eyes, 5.68 ± 1.64 in 15 initial stage eyes, 9.09 ± 7.65 in 24 advanced form eyes, 5.40 ± 1.42 in 11 disciform scar eyes, and 5.36 ± 1.72 in 29 fellow eyes. The aqueous flare value was significantly (P<0.01) higher in eyes with the advanced form of SDMD than in the fellow eyes. There were no significant differences in aqueous flare values between eyes with predisposing stage, initial stage, and disciform scar and fellow eyes. The aqueous flare value increased significantly with increasing area of neovascular membrane (R\s=0.68, P<0.01). Conclusion: The present results suggest that the aqueous flare increases with increasing neovascular membrane area in eyes with SDMD, and decreases with scarization of the neovascular membrane.     

Familial exudative vitreoretinopathy: surgical intervention and visual acuity outcomes

Background: Familial exudative vitreoretinopathy (FEVR) is a hereditary condition that may lead to vitreous hemorrhage and traction retinal detachment necessitating surgical intervention. In this paper we review the results of surgery on seven such patients (eight eyes). Methods: Seven patients (eight eyes) were followed up after surgery that had been performed because of vitreous hemorrhage and/or traction retinal detachment due to FEVR, in an effort to evaluate outcomes. Parameters that were noted were the current age, gender, age at the time of first surgery, length of follow-up and postoperative retinal status and visual acuity. Results: Seven patients (eight eyes) ranging in age from 6 months to 44 years with a mean of 24.7 and a median of 26 years were followed. There were three females and four males. The lowest age at which surgery was first performed was 6 months and the highest was 28 years, with a mean of 14.7 and a median of 17 years. Six of the 8 eyes were reattached following surgery, although some required multiple procedures. Conclusion: Vitreoretinal surgery may be of benefit in helping to preserve some degree of vision in eyes of patients with FEVR who develop vitreous hemorrhage and/or retinal detachment.Presented at the combined meeting of the Club Jules Gonin and the Retina Society, 3 September 1996     

Iatrogenic choroidal neovascularisation following argon laser photocoagulation for choroidal malignant melanoma

Background: Choroidal neovascularisation is known to occur following photocoagulation for choroidal melanomas. Its occurrence rate, possible causes and clinical impact were studied. Methods: Post-treatment fluorescein angiograms were reviewed from 18 patients who had received argon laser photocoagulation as sole treatment of their small choroidal melanomas, to look for choroidal neovascularisation. Where it was found an assessment of its clinical impact was made. Results: choroidal neovascularisation was found in 50% of cases. Choroidoretinal neovascularisation, found in five patients, caused vitreous haemorrhage in one patient but was otherwise benign. Choroidovitreal neovascularisation was found in four patients. It occurred early and altered their clinical management. Three of these patients had a vitreous haemorrhage, one of whom also suffered a retinal detachment. The three diabetic patients in the series all developed aggressive choroidovitreal neovascularisation. Tumour size, tumours location and number of treatment sessions did not appear to affect the occurrence of choroidal reovascularisation, nor did other medical or ocular conditions except for diabetes. Conclusion: Choroidal neovascularisation occurs commonly after melanoma photocoagulation. Although sometimes benign, it can be aggressive, particularly in diabetic patients, in whom it might be better to consider different forms of tumour treatment.     

Tolerance of human fetal retinal pigment epithelium xenografts in monkey retina

Background: RPE transplantation offers the possibility of treating certain forms of retinal degeneration. Understanding how to optimize the surgical technique for performing RPE transplantation, especially in primates, is therefore of considerable interest. Methods: Fifteen patch RPE transplants were performed in six monkeys. The transplant sites were examined at follow-up by ophthalmoscopy, biomicroscopy, fluorescein angiography and histology. Foveal and peripheral retinal transplants were compared. Results: Human fetal RPE xenografts can survive without rejection for at least 6 months after transplantation in monkey retina. Such grafts form a basal lamina and make intimate contacts with the outer segments of the host. Both rods and cones retain a normal appearance when in contact with unrejected transplants. Rejection occurred in only 30% (3/10) of the peripheral but in 60% (3/5) of the foveal transplants. Conclusions: Cultured human fetal RPE patch transplants can survive and maintain local photoreceptor integrity for relatively long periods of time in monkey subretinal space without immunosuppression. Rejection, when it occurs, is more frequent near the fovea.     

The ultrastructure of parapapillary chorioretinal atrophy in eyes with secondary angle closure glaucoma

Background: The present study was performed to investigate the ultrastructure of deep retinal layers and choroid corresponding to the parapapillary chorioretinal atrophy in eyes with secondary angle-closure glaucoma. Methods: The glaucomatous eyes included two eyes enucleated due to iris ring melanoma with high intraocular pressure and one eye with neovascular glaucoma enucleated due to ocular pain. The control eyes included one eye enucleated due to choroidal malignant melanoma with normal intraocular pressure and one eye enucleated during surgery for supramandibular carcinoma. These eyes were studied with light and electron microscopy. Results: In the region of parapapillary chorioretinal atrophy of glaucomatous eyes, the retinal pigment epithelial cells showed degenerative changes, such as loss of basal in foldings and microvilli, degenerated mitochondria, vacuolar degeneration and irregular distribution of melanin granules. The photoreceptors were decreased in number in this area of glaucomatous eyes. The lumen of the choriocapillary vessels adjacent to the optic nerve was collapsed. Conclusion: These results elucidate the fine structures of deep retina and choroid in the region of parapapillary chorioretinal atrophy of glaucomatous eyes, and suggest that the reduced choroidal perfusion might be the pathogenetic mechanism of glaucomatous parapapillary chorioretinal atrophy.     

Fundus pulsation measurements in diabetic retinopathy

Background: There is experimental evidence that retinal blood flow is impaired in patients with diabetes mellitus. Much less attention has been paid to choroidal blood flow. Hence it was the aim of the present study to investigate choroidal blood flow in diabetic retinopathy. Methods: A new noninvasive laser interferometric technique was used to measure fundus pulsations in the macula. The fundus pulsation amplitude, which is the maximum distance change between cornea and retina during the cardiac cycle, is a measure of local pulsatile blood flow. The eyes (n = 214) were divided into four groups according to the modified Airlie House classification: (1) no retinopathy (control group), (2) background retinopathy, (3) moderate to severe preproliferative retinopathy, (4) proliferative retinopathy. In 83 eyes of different groups fundus pulsation measurements were repeated after 1–6 weeks. Results: Fundus pulsation amplitudes were significantly smaller in group 4 than in the control group (P < 0.027). The reproducibility of the measurements was high and did not differ among the study groups. Conclusions: Local fundus pulsations in the macula are reduced in proliferative diabetic retinopathy, which is compatible with previous findings of reduced choroidal blood flow in late stages of the disease. Laser interferometric measurement of fundus pulsations is non-contactile, assures optimal comfort for the patient and could be used for the long-term observation of patients with diabetes mellitus.     

Epidemiologic characteristics of rhegmatogenous retinal detachment in Kumamoto,Japan

Background: The epidemiology of rhegmatogenous retinal detachment in Asians is not well known. We studied the epidemiologic characteristics of rhegmatogenous retinal detachment in Kumamoto, Japan. Methods: The study was based on a retrospective chart review of hospital patients who were treated for primary rhegmatogenous retinal detachment in 1990. The data were collected from seven hospitals in the Kumamoto area. Results: From a population of 1 840000, 192 residents developed retinal detachment. The annual incidence was therefore 10.4 per 100000 population (9.6 for males, 11.2 for females). The incidences of three types of detachment — nontraumatic phakic, aphakic, and blunt trauma — were 9.8, 0.5, and 0.2 per 100000 population, respectively. In 109 of 180 patients (60.6%) with nontraumatic phakic detachment, retinal breaks were associated with lattice degeneration. In females, 14 of 106 nontraumatic phakic cases (13.2%) were secondary to macular holes. Conclusion: Compared with previously published studies from other countries, the incidence of detachments associated with lattice degeneration and macular hole was higher, while the incidences of aphakic detachment and detachment due to blunt trauma were lower in Japan. Racial factors and living habits may affect the development of retinal detachment.     

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     

Hypoxia precedes the development of experimental preretinal neovascularization

Background: Although the mechanism of preretinal neovascular growth in the cell-injected rabbit eye model is not known, it has been proposed that the initial vasodilation and eventual development of neovascularization may be attributable to inflammatory mediators. However, an alternative explanation involving hypoxia has not been considered. The purpose of this study was to measure preretinal oxygen tension prior to the development of preretinal neovascularization in the cell-injected rabbit eye. Methods: In the rabbit, intravitreous injections of 250 000 homologous dermal fibroblasts were performed on one eye; the fellow (control) eye was injected with vehicle. Preretinal oxygen tension over the myelin wing was measured using¹⁹F-NMR spectroscopy of a 30-l droplet of perfluorocarbon previously injected into the preretinal vitreous. Results: Compared to control eyes, fibroblast-injected eyes showed a 1.7-fold decrease in preretinal oxygen tension from the first time studied (1 day after cell injection) through the development of visible neovascularization. Hypoxia occurred without coexisting ophthalmoscopic evidence of vascular occlusion or, on days I and 3 after cell injection, retinal detachment. Conclusion: This result demonstrates for the first time that preretinal hypoxia precedes the development of reretinal neovascularization in the fibroblast-injected rabbit eye.     

Blood-retina barrier in acute retinal branch vein occlusion

Background: Extensive clinical studies on retinal branch vein occlusion have not yet been able to clarify its pathogenesis. A study designed to look at the associated blood-retina barrier changes may contribute to a better understanding of the different forms of evolution of this pathology. Methods: A prospective study was done in seven patients with recent large temporal branch vein occlusion. Vitreous fluorophotometry, fluorescein angiography and retinal colour photography were performed within the 1st week after the onset of symptoms, 1 week later, and at 12 and 24 weeks. Results: A more marked blood-retina barrier breakdown was found at 1, 2, 12 and 24 weeks in the eyes that later developed extensive capillary non-perfusion. Conclusions: Our results suggest that the breakdown of the blood-retina barrier may play an important role in the subsequent development of retinal nonperfusion in eyes with large branch vein occlusion. We postulate that the eyes that will present later extensive capillary nonperfusion develop, from the initial stages of the disease, a progressive ischaemic capillaropathy characterized by blood-retina barrier breakdown. Retinal pigment epithelium degeneration and arterial lumen narrowing, secondary to the vein obstruction, may help to increase and perpetuate the blood-retina barrier breakdown during the first 6 months after the occlusion.     

Pseudophakic retinal detachment: anatomic and visual results

Background: Our purpose was to report the anatomic and visual results of pseudophakic retinal detachment surgery in a large series of consecutive cases and to analyze the risk factors for anatomic and functional failure. Methods: This retrospective study covered 290 primary cases of idiopathic rhegmatogenous retinal detachment operated on by the same surgeon during an 8-year period. Data relating to 26 pre-, per-, and postoperative variables were studied. For the statistical analyses we used both Chi-square and stepwise logistic regression tests. Results: Vitreous loss occurred in 56 cases (19.3%), and the retina detached more than 2 years after lens extraction in 108 cases (37.2%). Breaks could be identified in 249 cases (85.8%), and the macula was involved in 235 (81%). The overall reattachment rate was 85.2% (247/290), and a postoperative visual acuity of 0.5 D or more was attained in 49.6% of cases (144/290). We found no differenc between phakoemulsification, extracapsular, intracapsular techniques or between anterior chamber, posterior chamber, iris-fixated lenses as regards anatomic and functional outcomes. Proliferative vitreoretinopathy (PVR) and photoreceptor dysfunction were the main causes of anatomic and functional failure respectively. We identified extensive detachment, preoperative choroidal detachment, intraoperative hemorrhage and surgery for PVR as predictors of anatomic failure, while preoperative inflammation, preoperative PVR of grade B or worse, and surgery for PVR were predictors of functional failure. Conlusion: In this series, anatomic and visual results of reattachment surgery were much more affected by detachment features and by PVR than by the techniques and complications of cataract surgery.     

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.     

Indirect scatter laser photocoagulation to subfoveal choroidal neovascularization in age-related macular degeneration

Background: Occult choroidal neovascularization (CNV), poorly defined on fluorescein angiography, is present in the majority of patients with exudative complications of age-related macular degeneration. For patients who present with this type of subfoveal CNV but who have useful visual acuity, no form of treatment is of proven benefit. Accordingly, a pilot randomized trial of indirect laser treatment was performed. The rationale of this treatment was to inhibit the CNV through laser-induced effects on the retinal pigment epithelium. Methods: Patients with occult subfoveal CNV without retinal pigment epithelial detachment and with visual acuity of 20/200 or better were randomized to treatment or control groups. A grid of laser burns was applied to the macula beyond the area of serous retinal detachment and of angiographically defined occult CNV Results: After an average follow-up of 38 months, there was no difference in mean final visual acuity (0.12 treated, 0.14 control) or clinical outcome between treated and untreated groups. Fluorescein angiography showed gradual enlargement in the occult CNV in 58% of eyes in both groups. A decrease in visual acuity to worse than 20/200 (54% of treated, 50% of control eyes) was associated with ingrowth of well-delineated CNV (6 treated, 7 control eyes) or progression to a fibroglial or atrophic scar (11 treated, 8 control eyes). Conclusions: No benefit was demonstrated for scatter photocoagulation of the macula in patients with age-related macular degeneration and occult subfoveal CNV with initially good visual acuity. There were, however, no complications related to treatment.     

Retinopathy in diabetic hypertensive monkeys: a pathologic study

Background: No satisfactory primate model of diabetic retinopathy has been produced. The clinical picture of microangiopathic retinopathy in diabetic hypertensive monkeys has been previously reported. The present study describes the pathologic findings of these animals. Methods: Eleven eyes of six monkeys (five rhesus, one cynomolgus) were studied. Diabetes mellitus was either spontaneous or induced by streptozocin; mild arterial hypertension was either spontaneous or induced by fludrocortisone acetate. In two monkeys, the horseradish peroxidase tracer technique was employed. Trypsin flat preparations of the nasal retinal vasculature were prepared. The material was studied by light and electron microscopy. Results: We divided the development of the microangiopathic retinopathy into three stages. In the early stage, background retinopathy was characterized by microvascular abnormalities and capillary dropout. Massive vascular leakage, intraretinal exudates and hemorrhage, cystoid degeneration, and cotton-wool spots were features of an exudative retinopathy in the second stage. In the final stage, chronic ischemic retinopathy was characterized by vascular occlusions and areas of retinal atrophy. Conclusion: Microangiopathic retinopathy in diabetic monkeys with mild hypertension presented many features of human diabetic and hypertensive retinopathy, except vitreous neovascularization.