Detection system for ocular refractive error measurement

An automatic and objective system for measuring ocular refractive errors (myopia, hyperopia and astigmatism) was developed. The system consists of projecting a light target (a ring), using a diode laser (lambda = 850 nm), at the fundus of the patient's eye. The light beams scattered from the retina are submitted to an optical system and are analysed with regard to their vergence by a CCD detector (matrix). This system uses the same basic principle for the projection of beams into the tested eye as some commercial refractors, but it is innovative regarding the ring-shaped measuring target for the projection system and the detection system where a matrix detector provides a wider range of measurement and a less complex system for the optical alignment. Also a dedicated electronic circuit was not necessary for treating the electronic signals from the detector (as the usual refractors do); instead a commercial frame grabber was used and software based on the heuristic search technique was developed. All the guiding equations that describe the system as well as the image processing procedure are presented in detail. Measurements in model eyes and in human eyes are in good agreement with retinoscopic measurements and they are also as precise as these kinds of measurements require (0.125D and 5 degrees).     

Studies of the distribution of lipofuscin in the retinal pigment epithelium using high-resolution TV laser scanning ophthalmoscopy

BACKGROUND: The fundus autofluorescence imaging technique has been modified allowing improved image resolution (768 x 572 pixel). We present results of fundus autofluorescence studies using this technique. MATERIALS AND METHODS: Fundus autofluorescence was studied in 286 eyes of 143 patients with retinitis pigmentosa, macular dystrophies and age-related macular degeneration using a confocal laser scanning ophthalmoscope prototype (Zeiss, Oberkochen; excitation wavelength: 488 nm, cut-off filter at 521 nm). RESULTS: The spatial distribution of autofluorescence was different in all diseased eyes investigated compared to the normal pattern of fundus autofluorescence. Each disorder showed a specific fundus autofluorescence appearance. CONCLUSIONS: The advanced technique of imaging fundus autofluorescence allows detailed studies of the lipofuscin distribution. In vivo analysis of the dynamics of accumulation and degradation of lipofuscin in eyes with tapeto-retinal dystrophies and age-related macular disease may contribute to elucidation of the pathogenesis of these disorders.     

Age-related changes in the tiger salamander retina

Tiger salamanders have been used in visual science because of the large size of their cells and the ease of preparation and maintenance of in vitro retinal preparations. We have found that salamanders over 27 cm in length show a variety of visual abnormalities. Compared to smaller animals (15-23 cm), large animals exhibited a decrease in visual responses determined by tests of the optomotor reflex. Small animals responded correctly an average of 84.5% of the time in visual testing at three light levels compared to an average of 68.4% for the large animals with the poorest visual performance at the lowest level of illumination. In addition, large animals contained (i) histological degeneration of the outer retina, in particular, loss and disruption of outer segments and abnormalities of the retinal pigmented epithelium, (ii) loss of cells, including photoreceptors, by apoptosis as evaluated with the TUNEL technique, and (iii) an increase in the number of macrophages and lymphocytes within the retina as determined by morphological examination. These histological changes were present in all large animals and all quadrants of their retinas. In contrast, small animals showed virtually no retinal degeneration, no TUNEL-positive cells, and few immune-like cells in the retina. Since large animals are also older animals. the visual changes are age-related. Loss of visual function and histological degeneration in the outer retina also typify aged human eyes. Thus, we propose that large salamanders serve as an animal model for age-related retinal degeneration. In addition to providing a source of aging retina that is readily accessible to experimental manipulation, the salamander provides a pigmented retina with a mixed (2:1, rod:cone) population of photoreceptors, similar to the degeneration-prone parafoveal region of the human eye.     

Serotonin-induced constriction of ocular arteries in atherosclerotic monkeys. Implications for ischemic disorders of the retina and optic nerve head

BACKGROUND: Ischemic disorders of the retina and optic nerve head, which constitute a common cause of visual loss, are usually seen in patients with atherosclerosis. OBJECTIVE: To test the hypothesis that serotonin, which is released when platelets aggregate, may produce vasospasm in atherosclerotic monkeys and, thus, may contribute to the ischemic disorders and that short-term dietary treatment of atherosclerosis causes the propensity to vasospasm to subside. METHODS: We studied the response of retinal and posterior ciliary circulation to serotonin in 18 atherosclerotic (25 eyes) and 5 normal (8 eyes) cynomolgus monkeys. The eyes were evaluated by color fundus photography and fluorescein fundus angiography. The eyes were examined under basal conditions and, at a different time, during the intravenous infusion of serotonin. In 6 of the 18 atherosclerotic animals, the evaluation was repeated 5 to 12 months after discontinuing the atherogenic diet (ie, the regression group). RESULTS: Serotonin had no effect in normal monkeys. In 18 atherosclerotic monkeys, serotonin produced transient occlusion or delayed filling of the central retinal artery and/or posterior ciliary artery (PCA) in 9 eyes of 9 animals, involving the central retinal artery in 5, lateral PCA in 8, and medial PCA in 5, in various combinations. In 6 animals (6 eyes) of the regression group, the vasoconstrictor effect of serotonin was abolished completely, except in the medial PCA in 1 eye. CONCLUSIONS: Serotonin, in the presence of atherosclerotic lesions, can cause transient, complete occlusion or impaired blood flow in the central retinal artery and/or PCA. We speculate that this mechanism may play a role in the development of ischemic disorders of the retina and optic nerve head. Discontinuing the atherogenic diet abolished or markedly improved the serotonin-induced vasoconstriction within a few months.     

Light injury to the retina. Manifestation of acute posterior multifocal placoid pigmentepitheliopathy (author's transl)

Light injury to the human eye has been correlated exclusively with wellknown thermal effects (e.g., solar maculopathy; photocoagulation). One may speculate whether clinical conditions exist in which the light impact from strong conventional light sources--otherwise innocuous--may become harmful to the retina. A case history is presented of a patient suffering from acute posterior multifocal placoid pigment epitheliopathy in which a possible relationship is discussed between the appearance of the fundus changes and the damage due to direct viewing of a halogen head light.     

Epidemiology of motor vehicle crash-related serious eye injuries

The Eye Injury Registry of Alabama has been collecting epidemiologic, treatment, final outcome, and rehabilitation information on serious ocular trauma since 1982. By December 31, 1989, 150 motor vehicle crash-related eye injuries had been registered. This is the largest series of motor vehicle crash-related serious eye injuries reported. The mean age of those injured was 29 years; 61% were between 16 and 35 years of age, and 73% were males. Ten individuals (7%) suffered bilateral eye injuries. The retina was injured in 47% of eyes. The initial visual acuity was 19/200 or worse (legal blindness) in 47% of eyes. Of eyes with at least 3 months of follow-up, 63% had worse than 20/200 initial visual acuity and 41% remained legally blind. Twelve percent of eyes required removal. Possibly due to the large number of blunt ruptures, motor vehicle crash-related eye trauma carries a particularly unfavorable treatment prognosis. Prevention of these injuries is therefore of extraordinary importance.     

Solar retinopathy in a hospital-based primary care clinic

BACKGROUND: Most reports of solar retinopathy describe epidemics of patients who go to the eye doctor after viewing a solar eclipse. Rarely is it encountered by the primary eye care provider during a routine eye examination. METHODS: For 26 months, patients who went to the primary care eye clinic and found to have macular lesions consistent with solar retinopathy were identified from the total clinic population. These patients were documented in a coded log and fundus photographs were obtained (when possible). RESULTS: Twenty-six eyes of twenty patients (0.14% incidence) were determined to have macular lesions consistent with solar retinopathy. Visual acuity was 20/25 or better in 100% of the patients and 85% were 20/20. Patients were predominantly men (75%) of middle age (average age, 43 years; SD, 11 years) with a history relevant for solar retinopathy (80%)--consisting of sungazing, 60%; looking at welding light without eye protection, 15%; substance abuse, 15%; and psychiatric condition, 5%. Forty percent had solar lesions in both eyes. Amsler grid testing revealed a defect in only 20%, and macular threshold visual-field testing was normal in all the eyes tested. CONCLUSIONS: This is the first report to characterize solar retinopathy in a primary eye care population. Management includes correct differentiation from other macular disorders, acquisition of a careful detailed history, and provision of patient education regarding the dangers of sungazing.     

Viral gastroenteritis among young children in northern Jordan

Perforating and penetrating globe injuries secondary to peribulbar and retrobulbar anaesthesia are often complicated by vitreous haemorrhage and retinal detachment. We describe the effectiveness of primary silicone oil tamponade in the repair of three perforated globes secondary to local anaesthesia for ophthalmic surgery. Three patients with axial myopia had peribulbar and retrobulbar anaesthesia for extracapsular cataract extraction (two patients) and cryotherapy (one patient). All eyes sustained a vitreous haemorrhage obscuring the view to the fundus. Retinal detachments were detected by B-scan ultrasound. In all eyes, scleral buckling, pars plana vitrectomy and silicone oil tamponade were performed as a primary surgical procedure. All the patients had complete anatomic reposition. In two patients, after two years follow-up, visual acuity was between 6/12 to 6/36 with the retina attached and no proliferative vitreoretinopathy (PVR). The third patient had blind painful eye and enucleation was performed. Primary use of silicone oil tamponade, in the management of perforated globe with retinal detachment due to local anaesthesia injection, is recommended.     

Heterogeneity in omphalocoele with absent radial ray complex

PURPOSE: To report a patient with a macular injury caused by a laser pointing device. METHODS: Case report. A healthy 34-year-old man was examined 2 days after he deliberately gazed into the beam of a laser-pointing device with his left eye for an estimated 30 to 60 seconds. His uncorrected visual acuity in each eye was 20/20. He reported a transient central scotoma in the left eye and headache after laser exposure. RESULTS: Both eyes were unremarkable except for a focal retinal pigment epithelial disturbance at the nasal edge of the fovea in the left eye. Fundus fluorescein angiography demonstrated window- defect type hyperfluoresence in the same location. CONCLUSIONS: Laser-pointing devices may cause macular injury when used inappropriately. Conformance with consumer safety recommendations should minimize potential hazards.     

Intravitreous injections of vascular endothelial growth factor produce retinal ischemia and microangiopathy in an adult primate

PURPOSE: The purpose of the study is to determine the effect of exogenous vascular endothelial growth factor (VEGF) on the primate retina and its vasculature. METHODS: Ten eyes of five animals were studied. Physiologically relevant amounts of the 165 amino acid isoform of human recombinant VEGF were injected into the vitreous of six healthy cynomolgus monkey eyes. Inactivated human recombinant VEGF or vehicle was injected into four contralateral control subject eyes. Eyes were assessed by slit-lamp biomicroscopy, tonometry, fundus color photography, fundus fluorescein angiography, light microscopy, and immunostaining with antibodies against proliferating cell nuclear antigen and factor VIII antigen. RESULTS: All six bioactive VEGF-injected eyes developed dilated, tortuous retinal vessels that leaked fluorescein. Eyes receiving multiple injections of VEGF developed progressively dilated and tortuous vessels, venous beading, edema, microaneurysms, intraretinal hemorrhages and capillary closure with ischemia. The severity of the retinopathy correlated with the number of VEGF injections. None of the four control eyes exhibited any abnormal retinal vascular changes. The endothelial cells of retinal blood vessels were proliferating cell nuclear antigen positive only in the bioactive VEGF-injected eyes. CONCLUSION: Vascular endothelial growth factor is sufficient to produce many of the vascular abnormalities common to diabetic retinopathy and other ischemic retinopathies, such as hemorrhage, edema, venous beading, capillary occlusion with ischemia, microaneurysm formation, and intraretinal vascular proliferation.     

Treatment of oesophageal carcinoma at a small rural hospital

OBJECTIVE: For the primary treatment of pseudophakic retinal detachment, vitrectomy could be preferred to episcleral buckle because it does not induce myopia, it clears opacities of the posterior capsule and/or of the vitreous and allows a good visualization of the fundus. This study was determined to compare the anatomic and functional results of vitrectomy and episcleral buckle. METHODS: from 1990 to 1995, 93 pseudophakic eyes were operated on for retinal detachment. 75 eyes were treated with episcleral buckle (group I) and 18 eyes were treated with vitrectomy (group II). In the latter group, 4 eyes had a giant tear, and 4 other eyes had a macular hole associated with high myopia. The anatomic and functional results were analyzed retrospectively. RESULTS: The retina was reattached with one operation in 67 eyes of group I (89%) and 16 of group II (89%). More than one month after the first operation, the retina redetached in 6 eyes of Group I (8%) and one eye of group II (6%). The causes of failure were a) new or missed retinal tears [Group I: 10 eyes (13%), group II: 3 eyes (17%)] and b) vitreoretinal proliferation (group I: 4 eyes, group II: 0). The number of subsequent reoperations for failures or recurrences was higher in group I than in group II. At the final examination, the retina was attached in 73 eyes of group I (97%) and in 18 eyes of group II (100%). The Kruskal-Wallis test did not detect any difference between the two groups concerning the pre- or postoperative visual acuities. CONCLUSION: Vitrectomy seems as effective as episcleral buckle for the treatment of pseudophakic retinal detachment and offers additional advantages.     

Defective phagocytosis in systemic lupus erythematosus

The authors describe a case of traumatic retinal dialysis with retinal detachment from a water balloon slingshot during a "water balloon war." A 31-year-old woman presented with decreased visual acuity in her right eye 2 days after being hit by a water balloon. The visual acuity in the right eye was counting fingers and fundus examination showed subtotal retinal detachment secondary to a superonasal dialysis. The patient underwent a scleral buckling procedure with external drainage, and at 18 months visual acuity was stable at 20/50 with attached retina. Water balloon eye injuries can result in permanent visual loss. More public awareness needs to be created regarding the potential harmful effects of this commonly used "toy."     

Infection and associated risk factors in the immediate postoperative period of pediatric liver transplantation: a study of 176 transplants

BACKGROUND AND OBJECTIVE: To assess the outcomes of vitreoretinal surgery in the treatment of vision-threatening posterior segment complications of X-linked retinoschisis. PATIENTS AND METHODS: The authors performed a retrospective analysis of 16 eyes from 11 patients who underwent vitreoretinal surgery. All the patients had a documented positive family history of X-linked retinoschisis, and all patients had bilateral macular disease. RESULTS: The ages of the patients ranged from 14 months to 37 years (mean age 15.1 years; median age 11.5 years), and postoperative follow-up ranged from 3 months to 10 years (mean 2.8 years; median 1 year). The indications for surgical intervention included rhegmatogenous retinal detachment (12 eyes), vitreous hemorrhage (2 eyes), progression of the schisis cavity through the fovea (2 eyes), cataract associated with a persistent hyperplastic primary vitreous-like condition (2 eyes), and exudative maculopathy (1 eye). The primary surgical intervention included pars plana vitrectomy alone (7 eyes), pars plana vitrectomy and pars plana lensectomy (4 eyes), and a scleral buckle procedure alone (5 eyes). Surgical success (defined as reattachment of the retina, removal of media opacities, or arrest of schisis progression) was achieved in 14 of 16 eyes, after an average of 1.2 procedures per eye. The major reason for reoperations was recurrent retinal detachment due to proliferative vitreoretinopathy. Two eyes were eventually enucleated due to pain associated with neovascular glaucoma resulting from recurrent retinal detachment. Of the remaining 14 eyes, visual acuity improved in 8 eyes and remained unchanged in 6 eyes. CONCLUSION: Vitreoretinal surgery is often helpful in stabilizing or improving visual function in patients with posterior segment complications from X-linked retinoschisis.     

A case of congenital retinoschisis with unexpected appearance and spontaneous regression

A case of congenital retinoschisis, with both unexpected appearance and spontaneous regression, is reported. The patient, a 22-year-old man, had been diagnosed with congenital retinoschisis when he was 11 years old. The ocular fundus showed bilateral foveal retinoschisis and peripheral retinoschisis in the right eye. Early in November 1991, he visited our hospital and complained of a visual field defect in the left eye. The ocular fundus of the left eye showed high ballooning retinoschisis. However, two weeks later, the ballooning retinoschisis had completely disappeared. Appearance and regression of peripheral retinoschisis of congenital retinoschis in an adult is a very rare occurrence.     

Long-term follow-up after endoscopic sphincterotomy for bile duct stones in patients younger than 60 years of age

PURPOSE: To study the clinical histories and courses of six patients with choroidal neovascularization secondary to endogenous Candida albicans chorioretinitis. METHODS: The medical records, fundus photographs, and fluorescein angiograms of six patients who developed C. albicans chorioretinitis secondary to candidemia and who subsequently developed choroidal neovascularization in one or both eyes were reviewed. RESULTS: The six patients ranged in age from 18 to 79 years. Four were women and two men; all but one showed evidence of bilateral chorioretinal scarring secondary to C. albicans chorioretinitis. All patients had been treated successfully with systemic antifungal therapy (amphotericin B). Two weeks to two years after the chorioretinitis, choroidal neovascularization developed in one eye (four cases) or both eyes (two cases). The neovascularization on initial examination was subfoveal in four eyes, extrafoveal in three eyes, and juxtafoveal in one eye. Laser photocoagulation was used in four of the eight involved eyes. In these cases, the active choroidal neovascularization was brought under control. In one eye, the patient had submacular surgery for excision of the choroidal neovascular membrane. Final visual acuities ranged from 20/20 to 20/200 in treated eyes and from 20/50 to 20/400 in untreated eyes. CONCLUSION: Choroidal neovascularization is a potential cause of late visual loss in patients who have had C. albicans sepsis and endogenous C. albicans chorioretinitis. Eyes that have chorioretinal scarring from C. albicans chorioretinitis should be watched for the development of choroidal neovascularization. Laser photocoagulation or perhaps surgical excision of the neovascular complex may be of benefit in selected cases.     

Comparative linkage maps for the mosquitoes (Culex pipiens and Aedes aegypti) based on common RFLP loci

OBJECTIVE: To investigate the ocular complications in pediatric bone marrow transplantation (BMT) patients. DESIGN: Cross-sectional study. PARTICIPANTS: A total of 29 pediatric BMT patients were studied. TESTING: Comprehensive ophthalmic check-up, including best-corrected visual acuity, intraocular pressure (IOP), Schirmer's test, tear breakup time, and slit-lamp and fundus examinations, was performed. MAIN OUTCOME MEASURES: Tear film instability and its related complications, IOP, cataract, and fundus lesions were measured. RESULTS: The mean age of patients was 9.1 years (range, 1.5-15 years). The mean post-BMT duration was 20.2 months (range, 3-54 months). Fifteen patients (51.7%) had tear abnormalities. Subconjunctival fibrosis was detected in two patients (6.9%). Dry and scaly skin of the eyelids was seen in one patient (3.4%). Lens opacities were found in 2 (33.3%) of 6 irradiated patients and 2 (8.7%) of 23 nonirradiated patients. Two patients (6.9%) had fundus changes, one with unilateral epiretinal membrane and the other with bilateral multiple discrete chorioretinal hypopigmented lesions in the middle to peripheral part of the retina. The overall complication rates for the anterior and posterior segments were 75.8% and 6.9%, respectively. CONCLUSION: Ocular manifestations of BMT in children are not uncommon. The most common anterior segment problem is tear dysfunction. Posterior segment complications are less common but do exist. High rate of cataract formation is reported, and this probably is the most important long-term "amblyogenic" problem in these immature eyes. Awareness and management of these problems with routine eye examination and early intervention are recommended.     

Vitrectomy for traction macular detachment in diabetic retinopathy

BACKGROUND: A small number of eyes with proliferative diabetic retinopathy develop massive central fibrovascular membranes characterized by vitreoretinal tractions along the arcades and optic disk and retinal traction lines extending through the macula. The aim of our study was first to present the results of vitrectomy for removal of these central membranes and second to determine the correlation between preoperative parameters and postoperative visual outcome. SUBJECTS AND METHODS: We treated 28 eyes with severe central fibrovascular diabetic membranes by a modified bi-manual en bloc excision technique during vitrectomy. Preoperative examination included general status, visual acuity, slit-lamp investigation, binocular funduscopy, ultrasound investigation and visual evoked potentials (VEP). Further, we analyzed intraoperative complications and postoperative anatomic and functional outcomes. RESULTS: The retinas of 27 eyes with central traction retinal detachments were reattached by surgery. With a minimum of 6 months' follow-up, the macula remained attached in 24 eyes, while the retinas were completely attached in 22 eyes. Preoperative visual acuity was defective light perception to 0.1; an increase in visual acuity to maximal 0.1 was seen in 50% of the patients postoperatively. Preoperative visual acuity of light perception was associated with no functional improvement. Preoperative ultrasound investigation gave information about the real anatomic situation of the retina, especially if funduscopy was not possible. The other preoperative parameters could not predict correctly the functional outcome of vitrectomy in diabetics with severe central fibrovascular membranes because of the damage of the optic nerve and the retina. CONCLUSIONS: The high rate of anatomical reattachment after vitrectomy in diabetic eyes with severe central fibrovascular membranes is associated with a slight improvement of function; only preoperative visual acuity of hand motions or better was associated with an improvement of function.     

Human photoreceptor transplantation in retinitis pigmentosa. A safety study

OBJECTIVE: To establish the technical feasibility and safety of photoreceptor transplantation in retinitis pigmentosa. METHODS: A sheet of human photoreceptor cells was harvested from 2 human cadaveric eyes with a vibratome and transplanted into the subretinal spaces of 2 patients with advanced retinitis pigmentosa and visual acuity of no light perception by means of submacular surgery techniques. Preoperative and postoperative electrophysiologic testing, fundus photography, fluorescein angiography, and scanning laser ophthalmoscopy were performed. RESULTS: Twelve months after photoreceptor transplantation, the visual acuity of each patient remained no light perception. The temporal edge of the retinotomy in 1 patient was folded but was not associated with a retinal detachment. The patients were not immunosuppressed, and there was no evidence of rejection of the allogeneic transplant. Cystoid macular edema, uveitis, and macular pucker were not observed. CONCLUSION: A sheet of adult human photoreceptor cells can be harvested from human cadaveric eyes and safely transplanted to the subretinal spaces of patients with retinitis pigmentosa without systemic immunosuppression.