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Biomedical subjects

R A Mittra

Publications and source records attributed to R A Mittra.

At least 19 recordsLinked to original sources
PubMed2005

Vitreoretinal surgery for macular hole after laser assisted in situ keratomileusis for the correction of myopia.

UNLABELLED: AMS: To describe the characteristics and surgical outcomes of full thickness macular hole surgery after laser assisted in situ keratomileusis (LASIK) for the correction of myopia. METHODS: 13 patients (14 eyes) who developed a macular hole after bilateral LASIK for the correction of myopia participated in the study. RESULTS: Macular hole formed 1-83 months after LASIK (mean 13 months). 11 out of 13 (84.6%) patients were female. Mean age was 45.5 years old (25-65). All eyes were myopic (range -0.50 to -19.75 dioptres (D); mean -8.4 D). Posterior vitreous detachment (PVD) was not present before and was documented after LASIK on 42.8% of eyes. Most macular hole were unilateral, stage 4 macular hole, had no yellow deposits on the retinal pigment epithelium, had no associated epiretinal membrane, were centric, and had subretinal fluid. The mean diameter of the hole was 385.3 microm (range 200--750 microm). A vitrectomy closed the macular hole on all eyes with an improvement on final best corrected visual acuity (VA) on 13 out of 14 (92.8%) patients. CONCLUSIONS: This study shows that vitreoretinal surgery can be successful in restoring vision for most myopic eyes with a macular hole after LASIK.

Adult↗
PubMed2000

A combination light-pipe, soft-tipped suction, and infusion cannula instrument for macular translocation.

PURPOSE: To describe a combination light-pipe, soft-tipped suction needle, and infusion cannula instrument for use in macular translocation surgery. METHODS: Macular translocation surgery was performed in human cadaver and live rabbit eyes with a combination light-pipe, soft-tipped suction needle, and infusion cannula instrument. RESULTS: A combination light-pipe, soft-tipped suction needle, and infusion cannula can be used for macular translocation. This instrument is useful for relocating the retina after a 360 peripheral retinotomy is created. It can also be used for macular translocation with the scleral imbrication technique when superior movement of the fovea is required. When used in combination with another soft-tipped suction needle instrument, this surgical instrument allows precise bimanual placement of the retina with simultaneous infusion of liquid perfluorocarbon for fixating the macula to its new location. CONCLUSION: A combination light-pipe, soft-tipped suction needle, and infusion cannula instrument may be a useful tool for macular translocation surgery.

Animals↗
PubMed2000

The use of topical aqueous suppressants in the prevention of postoperative intraocular pressure elevation after pars plana vitrectomy with long-acting gas tamponade.

OBJECTIVE: To determine whether topical aqueous suppressant therapy applied after pars plana vitrectomy with gas tamponade prevents postoperative intraocular pressure (IOP) elevation. DESIGN: Prospective, nonrandomized comparative study. PARTICIPANTS: Forty-one patients who met inclusion criteria and underwent pars plana vitrectomy with gas tamponade (SF6 18%-20% or C3F8 12%-16%) over a 1-year period. INTERVENTION: Treatment eyes received topical aqueous suppressants at the end of surgery. MAIN OUTCOME MEASURES: Postoperative IOP at 4 to 6 hours, 1 day, and 1 week. RESULTS: Twenty-one control and 20 treatment eyes met the inclusion criteria. The IOP (in mmHg) measured at 4 to 6 hours (23.05 [control, 14.73 [treatment]) and 1 day (23.24 [control], 17.28 [treatment]) postoperatively showed a statistically significant difference between the groups (P = 0.0038) at 4 to 6 hours and a trend toward significance (P = 0.057) at 1 day. Eleven control and three treatment eyes had an IOP spike above 25 mmHg at 4 to 6 hours or 1 day postoperatively (P = 0.02), and six control eyes and one treatment eye had postoperative IOP greater than 30 mmHg. A pressure rise greater than 40 mmHg was seen in two control eyes and no treatment eyes. CONCLUSIONS: Use of topical aqueous suppressants after pars plana vitrectomy with long-acting gas tamponade is effective in preventing significant postoperative IOP elevation in most cases.

Administration, Topical↗
PubMed2000

Retinopathy progression and visual outcomes after phacoemulsification in patients with diabetes mellitus.

OBJECTIVES: To determine the rate of progression of diabetic retinopathy after phacoemulsification surgery, and whether surgeon experience and/or surgical duration adversely affect visual outcome. METHODS: A retrospective review of 150 eyes of 119 diabetic patients who underwent phacoemulsification surgery during a 5-year period was performed. Data collected included patient age, sex, type and duration of diabetes, diabetic control, associated systemic health factors, preoperative visual acuity and retinopathy grade, duration of surgery, intraoperative complications, and postoperative course. The effect of these factors on visual outcome and rate of retinopathy progression was studied by means of univariate and stepwise multivariate logistic regression analyses. Resident and private cases were compared. RESULTS: Visual acuity improved by 2 or more lines in 117 eyes (78%); 93 eyes (62%) had a final visual acuity of at least 20/40. Retinopathy progression was seen in 37 eyes (25%) with 6 to 10 months of follow-up. Preoperative nonproliferative diabetic retinopathy, proliferative diabetic retinopathy, and limited surgical experience were statistically associated with retinopathy progression and poor visual outcome. CONCLUSIONS: The visual results and rate of retinopathy progression after phacoemulsification surgery in our series did not differ significantly from those reported that used other techniques. Nonproliferative and proliferative diabetic retinopathy and surgical inexperience resulted in an increased rate of retinopathy progression. Arch Ophthalmol. 2000;118:912-917

Cataract↗
PubMed1999

Progression of diabetic retinopathy after endophthalmitis.

OBJECTIVE: To determine the effect of endophthalmitis on diabetic retinopathy. DESIGN: Noncomparative case series. METHODS: The records of all consecutive patients with endophthalmitis treated between 1992 and 1997 at the Medical College of Wisconsin were retrospectively reviewed. Those patients with diabetes mellitus were analyzed. PARTICIPANTS: From 77 reviewed records, 11 patients (12 eyes; 14%) were identified as diabetics with endophthalmitis and were studied. MAIN OUTCOME MEASURES: Stage of diabetic retinopathy, time to retinopathy progression, and visual acuity. RESULTS: Mean patient age was 68 years, and mean duration of diabetes was 11.7 years. Mean patient follow-up was 17 months. Of the six cases without evidence of retinopathy before the endophthalmitis, none went on to develop retinopathy. Of six eyes with pre-existing nonproliferative retinopathy, four showed evidence of progression within 6 months of the infection. Three developed severe proliferative disease and macular edema, and one developed severe nonproliferative disease. More patients without pre-existing retinopathy achieved a final visual acuity of 20/40 or greater. CONCLUSIONS: Patients with pre-existing diabetic retinopathy may be at increased risk for rapid retinopathy progression and a poorer visual outcome after endophthalmitis. These results support the concept that inflammation may exacerbate diabetic retinopathy.

Aged↗
PubMed1999

Visual outcomes after pars plana vitrectomy for epiretinal membranes associated with pars planitis.

OBJECTIVE: To evaluate the results of pars plana vitrectomy and membrane stripping for visually significant macular epiretinal membranes associated with chronic idiopathic pars planitis. DESIGN: Consecutive noncomparative case series. PARTICIPANTS AND METHODS: The records of all patients who underwent pars plana vitrectomy for pars planitis from 1988 through 1997 were retrospectively reviewed. Seven eyes of five patients who were diagnosed with visually significant epiretinal membranes associated with pars planitis and who underwent vitrectomy and membrane stripping were analyzed. Patients were diagnosed with pars planitis based on characteristic clinical signs and pertinent negative laboratory test results. INTERVENTION: Pars plana vitrectomy and epiretinal membrane stripping. MAIN OUTCOME MEASURES: Visual acuity and inflammatory grade were compared between the last preoperative visit and the most recent follow-up visit. Intraoperative and postoperative complications were also analyzed. RESULTS: The mean patient age was 31 years (range, 6 to 45 years). The mean duration of uveitis was 6.4 years (range, 6 months to 13 years). All patients were treated with combinations of periocular, topical, and oral corticosteroids before surgery. Five eyes had laser retinopexy, and two eyes had cryopexy to the inferior retina at the time of surgery. Five eyes had at least 3 Snellen lines of visual acuity improvement, and visual acuity in one eye worsened by 2 lines. Mean preoperative visual acuity was 20/73 (range, 20/50 to 20/300), and mean final visual acuity was 20/37 (range, 20/25 to 20/70). Five eyes had a final visual acuity of 20/40. Vitritis improved in all cases. Mean follow-up was 23 months (range, 3 to 54 months). Six of seven eyes had progressive cataract development, four of which underwent cataract extraction. No other intraoperative or postoperative complications occurred. CONCLUSIONS: Removal of epiretinal membranes associated with pars planitis can be safely performed and may result in improved visual acuity. Patients often require subsequent cataract extraction to obtain the best long-term final acuity.

Acute Disease↗
PubMed1999

Primary ocular Epstein-Barr virus-associated non-Hodgkin's lymphoma in a patient with AIDS: a clinicopathologic report.

OBJECTIVE: To report an unusual case of chronic multifocal chorioretinitis with vitritis in a patient with acquired immunodeficiency syndrome (AIDS) that was resistant to antiviral and antitoxoplasmic medication and required a retinal biopsy for definitive diagnosis. METHODS: Vitreous biopsy, pars plana vitrectomy, and retinal biopsy were performed. The vitreous biopsy material was sent for bacterial, fungal, and viral culture, and the vitreous cassette was sent for cytology. The retinal biopsy material was divided and sent for polymerase chain reaction testing for toxoplasmosis and virology and pathologic tissue analysis. RESULTS: Vitreous cytology showed a mixed population of lymphocytes and histiocytes, but all other microbiologic and virologic studies were negative. Tissue analysis revealed an infiltrate of atypical mononuclear cells extending from the inner limiting membrane through the outer plexiform layer characteristic of a B cell, non-Hodgkin's lymphoma of the central nervous system (NHL-CNS). In situ hybridization for the Epstein-Barr virus (EBV) was positive. An extensive systemic evaluation did not show evidence of extraocular tumor. CONCLUSION: Although rare, primary ocular NHL-CNS can be seen in patients with AIDS, and its clinical presentation often closely resembles other disorders. To our knowledge, this case represents the first ocular NHL in which EBV is shown to be associated.

Adult↗
PubMed1999

Retinopathy progression and visual outcomes after phacoemulsification in patients with diabetes mellitus.

PURPOSE: To determine the rate of progression of diabetic retinopathy following phacoemulsification surgery and to determine if surgeon experience and/or surgical duration adversely affect visual outcome. METHODS: A retrospective review of 150 eyes of 119 diabetic patients who underwent phacoemulsification surgery over a 5-year period was performed. Data collected included patient age, sex, type and duration of diabetes, diabetic control, associated systemic health factors, preoperative visual acuity and retinopathy grade, duration of surgery, intraoperative complications, and postoperative course. The effect of these factors on visual outcome and rate of retinopathy progression was studied. Resident and private cases were compared. RESULTS: The visual acuity improved by two or more lines in 117 eyes (78%). Ninety-three eyes (62%) had a final visual acuity greater than or equal to 20/40. Retinopathy progression was seen in 37 eyes (25%) followed up for 6 to 10 months. Preoperative nonproliferative diabetic retinopathy, prolonged surgical duration, and limited surgical experience were statistically associated with retinopathy progression. CONCLUSIONS: The visual results and rate of retinopathy progression after phacoemulsification surgery in our series do not appear to differ significantly from those reported using other techniques. Nonproliferative diabetic retinopathy, longer surgical duration, and surgical inexperience resulted in an increased rate of retinopathy progression.

Aged↗
PubMed1998

Visual outcomes following lensectomy and vitrectomy for combined anterior and posterior persistent hyperplastic primary vitreous.

OBJECTIVE: To determine the visual outcome after surgery for persistent hyperplastic primary vitreous using modern vitreoretinal techniques. DESIGN: Retrospective medical record review during a 5-year period (June 1992 to June 1997). Information recorded for each patient included age, medical history, sex, results of preoperative ocular examination, age at diagnosis, procedure performed, intraoperative and postoperative complications, location and number of sclerotomy sites, type of aphakic rehabilitation, amblyopic therapy given, final visual acuity, and length of follow-up. RESULTS: Fourteen patients who underwent surgical management of combined anterior and posterior persistent hyperplastic primary vitreous were identified. Eleven patients underwent aphakic rehabilitation and aggressive amblyopic therapy consisting of occlusive therapy for several waking hours each day. One additional older patient received aphakic rehabilitation only. Ten eyes (71%) achieved a visual acuity of 20/300 or better, and 8 (57%) obtained a final visual acuity of 20/100 or better. Average length of follow-up was 22 months (range, 4-57 months). Nine patients were fitted with an aphakic soft contact lens, 2 older patients had a posterior chamber intraocular lens placed at the time of vitrectomy, and 1 patient wore aphakic spectacles. CONCLUSIONS: With modern vitreoretinal techniques, aphakic rehabilitation, and aggressive amblyopic therapy, useful vision can be obtained in the majority of patients with combined anterior and posterior persistent hyperplastic primary vitreous.

Amblyopia↗
PubMed1998

Removal of dislocated intraocular lenses using pars plana vitrectomy with placement of an open-loop, flexible anterior chamber lens.

OBJECTIVE: There are many alternatives available to the vitreoretinal surgeon in the management of posteriorly dislocated intraocular lenses (IOL). The lens may be repositioned in the ciliary sulcus if there is adequate capsular support, but if this support is absent, it must either be sutured in place (to the sclera or iris) or exchanged for an anterior chamber (AC) IOL. Scleral-sutured IOLs can be associated with hemorrhage, cystoid macular edema, retinal detachment, and endophthalmitis (through the suture tract), and use sutures that must last for the lifetime of the patient. Anterior chamber IOLs (ACIOLs) are easier to implant but require a limbal incision for insertion. The authors sought to determine the safety and efficacy of combining removal of posteriorly dislocated IOLs with ACIOL placement. DESIGN: A retrospective chart review, in which all cases of dislocated IOLs managed at the authors' institution over the last 5 years were reviewed. Patient characteristics, pre-existing ocular conditions, preoperative visual acuity (VA), intraocular pressure (IOP), type of lens dislocated, operation performed, postoperative VA and IOP, and length of follow-up were recorded. RESULTS: A total of nine cases were identified. Seven of these underwent primary posterior chamber (PC) IOL removal with ACIOL implantation. One had an ACIOL placed after a sulcus-sutured PCIOL dislocated, and one had enough capsular support for placement of a PCIOL after removal of a plate haptic silicone lens. Of the seven primary ACIOL cases, the best-corrected VA improved in five cases, was unchanged in one (remained 20/20), and declined in another. The final postoperative VA (mean follow-up, 12 months) was 20/30 or better in five patients, and was limited by age-related macular degeneration and epiretinal membrane in the other two. A hyphema occurred in two patients and cleared in both without visual compromise. There was no evidence of corneal compromise or exacerbation of glaucoma in any of the patients. CONCLUSIONS: Given that the results and complication rates in this small series appear to be similar to those reported for sulcus-suture techniques, implantation of an ACIOL after removal of a posteriorly dislocated IOL appears to be a viable alternative to suture fixation in the absence of capsular support.

Adult↗
PubMed1998

The use of topical aqueous suppressants in the prevention of postoperative intraocular pressure elevation following pars plana vitrectomy with long-acting gas tamponade.

PURPOSE: To determine if topical aqueous suppressant therapy applied after pars plana vitrectomy (PPV) with gas tamponade successfully prevents postoperative elevation of intraocular pressure (IOP). METHODS: A prospective, controlled study was performed on patients who met inclusion criteria and underwent PPV with gas tamponade (SF6 18%-20% or C3F8 12%-16%) over a 1-year period. Treatment eyes received topical aqueous suppressants at the end of surgery. Postoperative IOP checks were performed at 4 to 6 hours, 1 day, and 1 week. RESULTS: Twenty-one control (C) and 20 treatment (T) eyes met the inclusion criteria. The IOP (in mm Hg) measured at 4 to 6 hours (23.05 [C], 14.73 [T] and 1 day (23.24 [C], 17.28 [T]) postoperatively showed a statistically significant difference between the groups (P = .0038) at 4 to 6 hours, and a trend toward significance (P = .057) at 1 day. Eleven control and 3 treatment eyes had an IOP spike above 25 mm Hg at 4 to 6 hours or 1 day postoperatively (P = .02), and 6 control and 1 treatment eye had a postoperative IOP above 30 mm Hg. A pressure rise above 40 mm Hg was seen in 2 control eyes and no treatment eyes. CONCLUSIONS: Use of topical aqueous suppressants following PPV with long-acting gas tamponade is effective in preventing significant postoperative IOP elevation in a majority of cases.

Adrenergic alpha-Agonists↗
PubMed1997

Recombinant hirudin prevents postoperative fibrin formation after experimental cataract surgery.

PURPOSE: The authors studied the effect of a direct acting antithrombin agent, desulfatohirudin variant 1 (Revasc, Ciba-Geigy, Ltd., Basel, Switzerland), on postoperative fibrin formation after cataract surgery in rabbits. METHODS: Phacoemulsification was performed in a masked fashion on 28 eyes of 28 New Zealand white rabbits. Ten control group eyes had lactated Ringer's solution in the infusion and an intracameral injection (approximately 1.5 ml) at the end of the case. Ten group 1 eyes received hirudin 100 micrograms/ml in the infusion and intracameral injection. Eight group 2 eyes had 100 micrograms/ml hirudin in the intracameral injection only. Using slit-lamp examination, all eyes were graded for the amount of fibrin and intraocular hemorrhage in a masked fashion on postoperative day 1. RESULTS: Comparison of the mean postoperative fibrin grade (0-4) in group 1 (mean = 0.3), group 2 (mean = 0.25) and the control group (mean = 3.4) revealed a statistically significant difference between hirudin-treated and control eyes (P = 0.0002 for group 1, P = 0.0005 for group 2). No intraocular hemorrhage was noted in any group. CONCLUSIONS: Recombinant hirudin significantly decreases postoperative fibrin formation in a rabbit cataract extraction model. Intracameral injection of hirudin alone appears to be at least as effective as infusion of hirudin throughout the case. With further study, this agent has potential for use in cataract surgery on patients known to be at high risk for postoperative fibrin formation.

Animals↗
PubMed1997

Intraocular injection of recombinant hirudin to prevent experimental postoperative fibrin.

PURPOSE: To test the efficacy of a single intraocular injection of various doses of recombinant desulphatohirudin variant 1 (Revasc) in a rabbit model after lensectomy-vitrectomy surgery. METHODS: Standard fragmatome lensectomies and core vitrectomies were performed on Dutch Belted rabbits. In a masked fashion, 17 control eyes received single intraocular injections of lactated Ringer's solution, and the treated eyes, with eight eyes per treatment group, received single intraocular injections of hirudin at doses of 0.02 microgram, 2 micrograms, 10 micrograms, 50 micrograms, or 200 micrograms. RESULTS: Intraocular injections of hirudin were effective in preventing postoperative fibrin formation at doses of 2 micrograms. There was no notable intraoperative bleeding. With an injection of 2.0 micrograms hirudin there was no hemorrhage at any time after surgery; with an injection of 200 micrograms hirudin, however, there was notable bleeding. CONCLUSION: Hirudin is effective in the prevention of postoperative fibrin formation with a single intraocular injection of 2.0 micrograms after lensectomy-vitrectomy surgery in the rabbit model. There was no bleeding at the effective dose of 2.0 micrograms; at 100 times the effective dose, however, there was significant postoperative bleeding.

Animals↗
PubMed1997

Golf-related ocular injuries.

Golf-related ocular injuries have been reported since the early 1900s. Although this type of ocular injury is fortunately a relatively rare occurrence, the effects are usually devastating. The purpose of this article is to review the mechanism of golf injuries, the prognosis for different types of golf-related injuries, and how such injuries might be prevented.

Eye Injuries↗