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Biomedical subjects

T A Rice

Publications and source records attributed to T A Rice.

At least 19 recordsLinked to original sources

Vitrectomy in patients with decreased visual acuity secondary to asteroid hyalosis.

PURPOSE: To evaluate the role of vitrectomy in patients with decreased visual acuity solely attributable to asteroid hyalosis. METHOD: We retrospectively reviewed the records of patients with asteroid hyalosis and identified those who underwent vitrectomy for symptomatic asteroid hyalosis alone. RESULTS: After vitrectomy, nine of 10 eyes (10 patients) had at least 1 line of improvement in nonstandardized best-corrected visual acuity. In one eye, vision was unchanged postoperatively. The average gain was 3.44 lines. CONCLUSIONS: A small percentage of patients with asteroid hyalosis have decreased visual acuity caused solely or primarily by the asteroid hyalosis. Vitrectomy in these patients may alleviate symptoms and improve visual acuity.

Aged↗

Prospective evaluation of the effect of pseudophakic cystoid macula edema on contrast sensitivity.

OBJECTIVE: To evaluate the effect of pseudophakic cystoid macular edema (PCME) on contrast sensitivity. DESIGN: Best-corrected visual acuity, fluorescein angiogram, and contrast sensitivity measurements were obtained before surgery and at 8 weeks and 8.5 months after surgery. Eyes were classified as having no PCME, transient PCME, or persistent PCME. PARTICIPANTS: The study population consisted of 31 consecutive patients undergoing extracapsular cataract extraction with posterior chamber intraocular lens implantation between September 1990 and March 1991. MAIN OUTCOME MEASUREMENTS: Outcomes were best-corrected visual acuity and contrast sensitivity. RESULTS: Analysis of variance showed a significant decrease for all spatial frequencies at 8 weeks (P < .005) and for higher frequencies at 8.5 months (P < .05) in both PCME groups and for higher frequencies at 8 weeks in the transient PCME group. CONCLUSION: Decrease in contrast sensitivity associated with PCME may account for persistent visual difficulties despite good Snellen visual acuity.

Cataract Extraction↗

Idiopathic epiretinal membranes. Ultrastructural characteristics and clinicopathologic correlation.

Current theories of idiopathic epiretinal membrane (ERM) pathogenesis, based mainly on clinical and autopsy studies, emphasize a glial tissue origin. The clinical and ultrastructural features of 101 cases of idiopathic ERMs removed from the macular area during vitrectomy were studied. The predominant cell type was retinal pigment epithelium (RPE) in 51 cases, fibrous astrocytes in 29 cases, fibrocytes in 14 cases, and myofibroblasts in 7 cases. Features of myofibroblastic differentiation were present in 64 cases. Myofibrocytes were more common in younger patients with shorter duration of symptoms. Fibrous astrocytes were more common in females. The high incidence of RPE cells in this series raises new questions regarding the pathogenesis of idiopathic ERMs.

Adolescent↗

Nuclear sclerosis after vitrectomy for idiopathic epiretinal membranes.

We performed a retrospective analysis of lens changes occurring after vitrectomy for idiopathic epiretinal membranes causing macular pucker on 75 consecutive phakic eyes. Thirty-five eyes (47%) had appearance or progression of nuclear sclerosis. There were no changes in anterior subcapsular cataracts and three eyes (4%) had minimal changes in posterior subcapsular cataracts. Based on univariate analysis, presence of preoperative nuclear sclerosis, length of follow-up period, and surgeon were found to be associated with the occurrence or progression of nuclear sclerosis. Differences between surgeons were largely accounted for by the difference in proportions with preoperative nuclear sclerosis, and differing lengths of follow-up. Kaplan-Meier life table analysis performed on 53 eyes with examination of fellow eyes and longer follow-up showed significantly more nuclear sclerosis in the operated on eye when compared to the fellow eye (log-rank test, P less than .0001).

Actuarial Analysis↗

Vitrectomy for macular pucker. Use after treatment of retinal tears or retinal detachment.

We review our experience and present an analysis of 119 consecutive cases of macular pucker treated by vitrectomy and removal of the epiretinal tissue following treatment for acute retinal tears (16 eyes) or rhegmatogenous retinal detachment (103 eyes). Vision improved postoperatively in 104 (87%) of the 119 eyes. Final visual acuity of 20/60 or better was achieved in 38 (75%) of 51 cases in which the macula had not been detached previously and in 12 (24%) of 52 cases with prior macular detachment. Two preoperative factors were associated with a final visual acuity of 20/100 or better: (1) macula not involved by the original retinal detachment, and (2) thin epiretinal membrane.

Adolescent↗

Vitrectomy for idiopathic epiretinal membranes causing macular pucker.

We used vitreous surgery to remove idiopathic epiretinal membranes from the macular area in 70 consecutive cases. The abnormal tissue was successfully removed in each case. Vision improved postoperatively in 61 eyes (87%), remained unchanged in six eyes (9%), and worsened in three eyes (4%). However, at the time of final examination vision was improved in only 47 eyes (67%), primarily because of the occurrence or progression of nuclear sclerosis, which occurred in 38 of 60 phakic eyes (63%). Four preoperative factors were associated with final visual acuity of 20/60 or better: (1) initial vision of 20/100 or better, (2) shorter preoperative duration of blurred vision, (3) thin epiretinal membrane, and (4) absence of traction retinal detachment.

Adult↗

Results and prognostic factors in vitrectomy for diabetic vitreous hemorrhage.

The final visual acuities and prognostic factors predictive of these results were analyzed in 353 eyes that had pars plana vitrectomy for nonclearing diabetic vitreous hemorrhage. Eighty-one percent of the eyes had improved visual acuities on final examination. The percentage of eyes that achieved a visual acuity of 20/100 or better and the percentage that achieved 5/200 or better increased during the study period. Preoperative factors associated with a favorable visual prognosis included the following: preoperative visual acuity of 5/200 or better, absence of iris neovascularization, absence of neovascular glaucoma, clear lens or minimal cataract, and panretinal photocoagulation of at least one fourth of the fundus. Intraoperative factors associated with a favorable visual prognosis included retaining the crystalline lens and absence of an intraocular gas bubble.

Adolescent↗

Vitrectomy for progressive proliferative diabetic retinopathy.

We analyzed the results of 105 diabetic vitrectomy cases. The vitrectomies were performed for progressive fibrovascular proliferation that caused epiretinal membranes, vitreopapillary traction, florid neovascularization, or subhyaloid hemorrhage, with or without substantial preoperative visual loss. Eyes with inactive retinal neovascularization, dense vitreous hemorrhage, traction retinal detachment involving the macula, or combined traction and rhegmatogenous retinal detachment were excluded. Seventy-four eyes (70%) had improved final vision. The final vision was unchanged in eight eyes (8%) and was worse in 23 eyes (22%). Factors associated with a favorable visual prognosis included the following: age of 40 years or less, preoperative visual acuity of 5/200 or better, absence of preoperative iris neovascularization, preoperative panretinal photocoagulation, and absence of an iatrogenic retinal break.

Adult↗

Results and prognostic factors in vitrectomy for diabetic traction retinal detachment of the macula.

The level of final visual acuity results and the prognostic factors predictive of the level were analyzed in 360 eyes that had pars plana vitrectomy for diabetic traction retinal detachment of the macula. Fifty-nine percent of the eyes had improved visual acuity on final examination. The percentage of eyes that achieved a final visual acuity of 20/100 or better and the percentage that achieved 5/200 or better increased from 21% to 36% and from 57% to 72%, respectively, during the study. Preoperative factors associated with a favorable visual prognosis were a visual acuity of 5/200 or better, the absence of iris neovascularization, a clear crystalline lens or only minimal cataract formation, clear media or only mild vitreous hemorrhage, panretinal photocoagulation of at least one fourth of the retina, and the absence of severe preoperative retinal neovascularization. Intraoperative factors associated with a favorable visual prognosis include the avoidance of performing a lensectomy, the absence of iatrogenic retinal breaks, and the avoidance of using intraocular gas bubbles.

Adolescent↗

Results and prognostic factors in vitrectomy for diabetic traction-rhegmatogenous retinal detachment.

The results of pars plana vitrectomy for diabetic traction-rhegmatogenous retinal detachment were analyzed in 172 eyes, and the factors associated with a final visual acuity of 5/200 or better were identified. Forty-eight percent of eyes had improved vision on final examination. The proportion of eyes with a final visual acuity of 20/100 or better and 5/200 or better remained virtually the same during the ten-year study interval. Preoperative factors associated with a visual acuity of 5/200 or better were a preoperative visual acuity of 5/200 or better, the absence of iris neovascularization, and the absence of retinal detachment involving the macula. The intraoperative factor associated with a final visual acuity of 5/200 or better was the absence of iatrogenic retinal breaks.

Adult↗

Krypton and argon laser photocoagulation for central serous chorioretinopathy.

Based on medical records, the authors divided 86 eyes of 84 patients with central serous chorioretinopathy with serous detachment of the macula and retinal pigment epithelial leakage on fluorescein angiography into three groups: no laser treatment (45 eyes), argon laser treatment (26 eyes), and krypton laser treatment (15 eyes). One or more episodes of recurrence developed during the follow-up period in 10 untreated eyes (22%), 9 argon-treated eyes (35%), and 0 krypton-treated eyes. The difference in recurrence rate between argon- and krypton-treated eyes was statistically significant. The findings suggest that whenever laser treatment is indicated, krypton red laser photocoagulation may reduce the incidence of recurrence in eyes with central serous chorioretinopathy.

Adult↗

Effect of scleral buckling on vector forces caused by epiretinal membranes.

Epiretinal membranes exert a perpendicular force on the retina that is directed toward the center of the vitreous cavity and tends to elevate the retina from the retinal pigment epithelium. A scleral buckle changes the eye wall from concave to convex and reverses the direction of the vector force oriented perpendicular to the eye wall. Therefore, when a scleral buckle is used, the force from an epiretinal membrane pulls the retina toward the retinal pigment epithelium instead of causing retinal detachment.

Eye↗

Experimental occlusion of the retinal vein.

We used a pars plana approach to experimentally induce retinal vein occlusions (RVO) in cats by the application of electric energy near the veins at the optic nerve head. This experimental model was utilized to study the natural evolution of thrombosis in the cilioretinal veins, which are located near the lamina cribrosa in the cat. We observed that occlusion of the retinal veins occurs by the formation of a thrombus and that with time there is associated endothelial cell proliferation and recanalization in each instance.

Animals↗

Results of vitrectomy for proliferative diabetic retinopathy.

The authors treated 1007 eyes with vitrectomy for complications of proliferative diabetic retinopathy. Indications for surgery were: vitreous hemorrhage, 353 eyes (35%); traction retinal detachment, 360 eyes (36%); combined traction-rhegmatogenous retinal detachment, 172 eyes (17%); and other progressive fibrovascular proliferation 122 eyes (12%). During the study period, the frequency of vitreous hemorrhage as an indication for surgery decreased from 42 to 25%, and other progressive fibrovascular proliferation increased from 5 to 22%. The frequency of traction and traction/rhegmatogenous retinal detachments did not change. The results of surgery varied according to the indication. Seventy-nine percent of eyes with vitreous hemorrhage obtained final vision of 5/200 or better. Similar results were obtained in 64% of eyes with traction detachment, 56% of eyes with rhegmatogenous detachment, and 81% of eyes with progressive fibrovascular proliferation. The percentage of eyes achieving final vision of 20/100 or better are as follows: vitreous hemorrhage, 48%; traction detachment, 27%; rhegmatogenous detachment, 24%; and progressive fibrovascular proliferation, 46%. The success rate improved in each anatomic category during the last 3 years of the study.

Diabetic Retinopathy↗

Prognostic factors in vitrectomy for epiretinal membranes of the macula.

A retrospective multivariate analysis of 264 consecutive cases of vitrectomy for removal of epiretinal membranes of the macula was performed. Two main preoperative prognostic factors were identified that were associated with the visual outcome of surgery: (1) the preoperative visual acuity, and (2) the duration of blurred vision before surgery. Discriminant functions constructed using these two factors allowed correct classification of eyes into an outcome group with good visual acuity with a 69% accuracy, and an 80% accuracy in classifying eyes into a group showing significant improvement in the level of visual acuity. Eyes that began with vision better than 20/100 tended to have slightly better postoperative visions than eyes with poorer preoperative visual acuity. However, eyes with worse preoperative vision tended to improve the greatest amount after surgery. Eyes with a longer history of blurred vision had poorer visual acuity after surgery and also less improvement in vision. Other statistically significant prognostic factors were identified; however, they did not appreciably improve the accuracy of the discriminant function in predicting visual outcome.

Adolescent↗

Prognostic indicators of success and failure in vitrectomy for diabetic retinopathy.

Results of pars plana vitrectomy for complications of diabetic retinopathy were analyzed by logistic regression analysis in 1007 eyes to determine the preoperative and intraoperative factors associated with visual success or failure. Preoperative factors associated with a poorer visual outcome (final visual acuity less than 5/200) include preoperative iris neovascularization, cataract, visual acuity less than 5/200 and traction or rhegmatogenous retinal detachment. Intraoperative factors associated with a greater chance of a poor visual result include use of intravitreal gas or air and creation of an iatrogenic retinal break or detachment. The presence of any one of these factors resulted in a 1.5 to 3.9 times greater risk of a poor final visual result. The regression coefficients may be combined to predict the likelihood of obtaining final acuity greater than or equal to 5/200 in eyes with various preoperative characteristics.

Adolescent↗

Vitreous hemorrhage after vitrectomy for diabetic retinopathy.

The records of 596 consecutive vitrectomy cases performed for complications of diabetic retinopathy were reviewed to determine the incidence of intraoperative and postoperative vitreous hemorrhage and to determine if blood cleared more rapidly in aphakic compared to phakic eyes. Uncontrollable intraocular bleeding occurred in two eyes (0.5%). Vitreous hemorrhage was present on the first postoperative day in 278 eyes (63%). This early hemorrhage cleared in an average of 9.1 weeks in phakic eyes and 3.4 weeks in aphakic eyes. Further vitreous hemorrhage occurred in 88 eyes (23%). Sixty-four percent of later hemorrhages occurred in 88 eyes (23%). Sixty-four percent of later hemorrhages occurred within six months of the operation and 80% occurred within one year. Later vitreous hemorrhage cleared in an average of 16.2 weeks in phakic eyes and 5.3 weeks in aphakic eyes. Of the 311 eyes with vitreous hemorrhage at some time during the postoperative course, twenty-nine eyes (9%) underwent reoperation to remove nonclearing blood. Nonclearing vitreous hemorrhage was the main cause of final visual loss in only 15 (3.4%) of 438 eyes with adequate follow-up, and 6 of these 15 eyes had final vision of 5/200 or better.

Adult↗