Complications Of Proliferative Diabetic Retinopathy Research Articles

Diabetic Retinopathy in Nnewi, Nigeria

The objective of this paper is to determine the incidence and pattern of diabetic retinopathy in a clinic population of diabetics in Nnewi. All consecutive new patients seen at the Diabetic Eye Clinic, Nnamdi Azikiwe University Teaching Hospital, Nnewi, Nigeria, between March 1997 and September 1998 were examined. Examination methods include interviewer-administered structured questionnaire, visual acuity test, external eye examination, refraction, tonometry, gonioscopy, binocular indirect ophthalmoscopy and slit lamp fundus examination with 78D non-contact lens. Data on patients with diabetic retinopathy were analyzed and presented in this report. 33 patients (61 eyes) out of 100 new patients had diabetic retinopathy. Of the 33 patients, 14 did not know that diabetes could cause visual loss; 16 had not consulted any eye health worker. None had laser or vitreo-retinal surgery. Six patients were bilaterally blind and another 6 had uniocular blindness. Visual impairment in the better eyes was recorded in 12 patients. All cases of bilateral blindness in this cohort were due to diabetic retinopathy and its complication (neovascular glaucoma). The severity of diabetic retinopathy is as follows: mild non-proliferative diabetic retinopathy (NPDR) 23 eyes; moderate NPDR 20 eyes; severe NPDR 2 eyes and proliferative diabetic retinopathy 16 eyes. Vitreous haemorrhage (4 eyes) and traction retinal detachment (8 eyes) complicated proliferative diabetic retinopathy. Concurrent diabetic maculopathy was found in 34 eyes viz: clinically significant macular edema (CSME) 33 eyes; Non-CSME 1 eye. Diabetic retinopathy is not rare in Nigerians. Diabetics should be educated on the ocular complications of the disease. Since laser and vitreo-retinal surgery will reduce visual loss in the patients, these facilities should be provided in eye hospitals in Nigeria.Nigerian Journal of Ophthalmology Vol. 8, No.1 (August 2000): pp 7-10KEY WORDS: Diabetic retinopathy, incidence, visual loss, Nigeria.

Ocular morbidity following renal transplantation.

Long-term visual outcome following renal transplantation is poorly documented in medical literature. The purpose of this study was to determine the ocular morbidity in a group of renal transplant patients receiving immunosuppressive therapy. Patients who had undergone renal transplantation were identified from the renal outpatient register, and patients who were at least 8 years posttransplantation were included in the study. Ocular examination was on average 14.6 years post-surgery. There were 43 males and 28 females, with ages ranging from 29 to 74 years. The patients had undergone renal transplantation between March 1968 and September 1986. The ophthalmic examinations were carried out over a 15-month period in a research clinic. Visual acuity was greater than or equal to 6/9 in 75% of the eyes. 10% of eyes had visual acuities of less than 6/24. Four eyes had central/branch retinal-vein occlusions; four eyes had posterior subcapsular lens opacities; three eyes had optic atrophy; one eye had complications of proliferative diabetic retinopathy; one eye had diabetic maculopathy and one eye had a central retinal artery occlusion. Only five eyes had irreversible visual loss resulting in visual acuities of less than 6/60. The incidence of sight-threatening complications in long-term survivors of renal transplantation was low. The results indicate that long-term prognosis for normal vision in patients who have undergone renal transplantation is good. Regular ophthalmic examinations are recommended for early detection of sight-threatening complications.

Surgical Results of Pars Plana Vitrectomy Combined With Phacoemulsification and Intraocular Lens Implantation for Complications of Proliferative Diabetic Retinopathy

To evaluate the effectiveness and safety of combining phacoemulsification (PEA), pars plana vitrectomy (PPV), and intraocular lens (IOL) implantation. Combined operations of PEA and PPV were performed in 76 eyes of 54 patients with cataract complicated by proliferative diabetic retinopathy (PDR). The mean follow-up period was 24.4 months. Gas tamponade was employed in 15 eyes. IOLs were implanted during surgery. Visual acuity improved by 2 lines or more in 59 eyes (78%). Forty-seven eyes (77%) without tamponade and 12 eyes (80%) with tamponade had improved visual acuity. Postoperative complications included fibrin reaction in 8 eyes (10%), posterior synechia of the iris in 11 eyes (14%), and recurrence of retinal detachment in 8 eyes (10%). The incidence of these complications and of additional operations was higher in eyes that required tamponade, which corresponded with the severity of each case and the complexity of the surgical procedures. Although further studies are indicated, this study suggests that the combined operation of PPV, PEA, and IOL implantation is safe and effective for patients with PDR. The choice of IOL may be correlated with postoperative complications.

Phacoemulsification for Cataract Following Pars Plana Vitrectomy

To determine if the technical aspects of phacoemulsification for removal of cataract following pars plana vitrectomy differ from those of phacoemulsification for removal of cataract in nonvitrectomized eyes. Twenty-two eyes that had undergone prior vitrectomy were identified through a retrospective review of chart notes and operative records of 1039 consecutive cataract extractions performed by one surgeon. Complications of proliferative diabetic retinopathy was the most common indication for prior vitrectomy. The predominant lens change was nuclear sclerosis. Deep anterior chambers with large anterior to posterior excursions of the iris lens diaphragm with simultaneous fluctuation in pupil size occurred during phacoemulsification. The posterior capsule was flaccid and mobile during lens cortex removal. No posterior capsules ruptured. Postoperative visual acuity improved in 91% of the patients. Prior vitrectomy was associated with diabetes and nuclear sclerotic cataract. Phacoemulsification in this patient population was associated with inadequate pupillary mydriasis, superior conjunctival scarring, intraoperative anterior chamber depth, pupil size, and iris lens excursions that hindered phacoemulsification tip placement. Posterior capsules were excessively flaccid, prone to rapid anterior and posterior excursions, and may have plaques that are resistant to intraoperative removal.

Neodymium: YLF Picosecond Laser Segmentation for Retinal Traction Associated With Proliferative Diabetic Retinopathy

To determine the applicability of laser segmentation for severing fibrovascular tissue and hyaloid interfaces in the treatment of tractional complications of proliferative diabetic retinopathy. A prototype neodymium:yttrium-lithium-fluoride (Nd:YLF) picosecond pulse photodisruptive laser was used in eight eyes (seven patients) with proliferative diabetic retinopathy as part of a Food and Drug Administration-approved phase 1 protocol. There were three indications for treatment: type I: distortion and shallow elevation of the macular caused by taut, adherent, posterior hyaloid interface (two eyes); type II: traction retinal detachment involving the fovea (two eyes); and type III: fovea-threatened, traction retinal detachment (four eyes). Traction release was accomplished by laser segmentation of the detached hyaloid interfaces and fibrotic, contracted proliferative tissue. The Nd:YLF uses low pulse energy (0.10 mJ, 1,000 pulses per second for 10 consecutive seconds) that allows tissue cutting near the retinal surface. Both type I eyes had relief of traction forces; visual acuity improved from 20/400 to 20/50 in one eye; the other remained stable. Of the two type II eyes, one had anatomic reattachment of the fovea with improvement in visual acuity (hand movements to 20/50); the second required vitrectomy. Of the four type III eyes, all had anatomic improvement; three maintained pretreatment acuity; the fourth eye developed vitreous hemorrhage at 6 months and underwent vitrectomy. Three treatments (two eyes) caused vitreous hemorrhage that resulted in a transient drop in acuity (1 to 2 lines). No patient developed a retinal break or choroidal hemorrhage. In a small pilot study, the Nd:YLF laser segmented proliferative tissue near the retinal surface and elevated hyaloid interfaces. In selected cases, this may enable flattening of traction retinal detachment or release of retinal distortion.

Subretinal hemorrhages in proliferative diabetic retinopathy.

To describe the clinical features of patients with advanced proliferative diabetic retinopathy who underwent vitrectomy and were found to have subretinal hemorrhages. The authors conducted a retrospective study of 49 patients with complications of proliferative diabetic retinopathy requiring pars plana vitrectomy and demonstrating the presence of subretinal hemorrhage. Preoperative, intraoperative, and postoperative clinical characteristics were evaluated. Patients were observed for a minimum of 6 months. The location, size, and clearance of subretinal hemorrhages revealed wide variation. Forty-two patients had focal subretinal hemorrhages, and 14 patients within this group had submacular hemorrhages. A retinal break was observed in 15 patients (31%). Only one patient required drainage of the subretinal hemorrhage to achieve retinal reattachment. Vitreous surgery resulted in 59% of patients achieving a visual acuity > or = 5/200. Seventy-nine percent had stable or improved vision, whereas 20% had worse vision after surgery. Subretinal hemorrhages appear to be an uncommon feature associated with long-term, advanced proliferative diabetic retinopathy and portend a guarded visual prognosis. These hemorrhages may occur spontaneously in previously untreated eyes and are often unsuspected until observed at the time of vitreous surgery. In general, removal of subretinal hemorrhages was not necessary to achieve macular anatomic attachment, and most patients experienced improved visual function after surgery. Diabetic subretinal hemorrhages may indicate a retinal break, and, therefore, careful ophthalmic inspection should be performed in these patients.

Recombinant Hirudin for Prevention of Experimental Postoperative Intraocular Fibrin

To determine the efficacy of a specific antithrombin agent (recombinant desulphatohirudin variant 1 [Revasc, Ciba-Geigy, Ltd., Basel, Switzerland]) administered in the infusion fluid to prevent early postoperative fibrin formation in a rabbit lensectomy and vitrectomy model. Standard fragmatome lensectomies and core vitrectomies were performed prospectively in a masked fashion on ten control eyes with lactated Ringer's infusion and on ten eyes treated with 10 microgram of recombinant hirudin/ml in the infusate. The amounts of fibrin and hemorrhage were graded in a masked fashion by using slit-lamp examination and indirect ophthalmoscopy on postoperative days 1 through 5 and on day 7. The difference in the mean grade of fibrin formed on the first postoperative day in the eyes treated with recombinant hirudin (mean, 0.9) in relation to the mean grade of fibrin in the control eyes (mean, 3.5) was statistically significant (P = .004). This difference was also significant on the second postoperative day (P = .01). None of the treated eyes developed intraoperative or postoperative hemorrhage. Recombinant desulphatohirudin variant 1 is an effective inhibitor of postoperative fibrin formation in a rabbit model and is not associated with an increased risk of intraoperative or postoperative bleeding at the tested dose. This drug may be a useful adjunct in vitreous surgery for both proliferative vitreoretinopathy and the complications of proliferative diabetic retinopathy.

Vitrectomy in diabetic patients with a blind fellow eye

Results of pars plana vitrectomy for complications of proliferative diabetic retinopathy were analysed in 32 consecutive patients with a blind fellow eye due to diabetic eye disease. The mean follow-up period was 22.3 months. Only 16% of all eyes examined had received full scatter photocoagulation prior to referral for vitrectomy. Out of 9 eyes with vitreous haemorrhage, 8 improved to a visual acuity of > or = 0.2 postoperatively. Amid 23 eyes which were vitrectomized for advanced traction retinal detachment, only 4 eyes improved to a postoperative visual acuity of > or = 0.02. In this group 12 eyes deteriorated after vitrectomy, 3 eyes progressing to no light perception. The postoperative visual outcome after vitrectomy for traction retinal detachment in this group of diabetics with a blind fellow eye (mean postoperative visual acuity 0.03 +/- 0.05) was significantly worse (p < 0.000) compared to a group of 196 patients with a seeing fellow eye who were vitrectomized for traction retinal detachment at our clinic (mean postoperative visual acuity 0.09 +/- 0.11). Therefore we conclude that traction retinal detachment in this subgroup of patients is a particularly severe presentation of diabetic retinopathy with a guarded functional prognosis after vitrectomy. Our results demonstrate the importance of timely full scatter photocoagulation and early vitrectomy in eyes with progressive fibrovascular proliferation not responding to panretinal photocoagulation. We conclude that especially diabetic patients with a blind fellow eye must be followed closely and assigned to vitrectomy at an earlier stage of their disease in order to improve functional prognosis.

Vitrectomy for Complications of Proliferative Diabetic Retinopathy: Functional Outcomes

To quantitate the effect of diabetic vitrectomy on each patient's visual system and function. The anatomic and visual acuity outcomes of diabetic vitrectomy among three surgeons at one institution over a 4-year time interval were studied. Outcome parameters describing the visual system function were defined and applied to quantitate the effect on visual system disability. The anatomic and visual success rates and prognostic factors in the cohort of 213 patients by standard statistical analysis were similar to previous studies. The study eye was the eye with better vision in 68 (32%) patients at the conclusion of the study, and vision was equal to the fellow eye in 35 (16%) patients. The mean impairment of the visual system by the American Medical Association Guidelines for Disability was reduced from 61% preoperatively to 50% postoperatively. The factor associated with greatest degree of reduction of impairment of the visual system was a previtrectomy diagnosis of vitreous hemorrhage. There was at least a one-step improvement of visual system function in 65 (31%) patients. Vitrectomy for complications of severe proliferative diabetic retinopathy is especially valuable in improving the patient's overall visual function.

Diode endolaser photocoagulation.

Endolaser photocoagulation was applied using a diode laser in 25 patients. Indications were for treatment of complications of proliferative diabetic retinopathy (17 patients), proliferative vitreoretinopathy (four patients), complex retinal detachments (three patients), and a retinal break (one patient). Good retinal and retinal pigment epithelial laser uptake was observed in all cases. The clinical appearance of the burn while it is being made is similar to that with the argon laser, but it is subtly lighter, especially in less-pigmented areas and eyes. Predictable clinical results and no adverse effects have been observed. While the clinical utility of the diode laser is analogous to that of standard argon endolaser systems, numerous logistical advantages are offered by this system.

Tractional Elevations of the Retina in Patients With Diabetes

Tractional retinoschisis and tractional retinal detachment are both complications of proliferative diabetic retinopathy. The two conditions are frequently confused because they are similar in diagnostic features. We determined the respective incidence of tractional retinoschisis and tractional retinal detachment in 200 eyes with tractional elevations of the retina in patients with diabetes. In 39 eyes, the diagnosis was unequivocally tractional retinoschisis because the retinal elevation maintained its concave contour despite the development of retinal holes. In 65 eyes, tractional retinal detachment was diagnosed with equal certainty, either because pigment lines were present or because the elevation, after a retinal hole developed, rapidly became convex and extended to the ora serrata. The remaining 96 eyes, in which retinal holes or pigment lines were absent, were classified by other features that had been tested for significance in the already diagnosed eyes. On that basis, the diagnosis was retinoschisis in 46 eyes and retinal detachment in 50 eyes.

PROLIFERATIVE DIABETIC RETINOPATHY

Extraretinal complications of proliferative diabetic retinopathy are caused by neovascular and/or fibrovascular tissue growth and include vitreous hemorrhage, retinal detachment, and other effects damaging the retina and/or optic nerve. Exact features of fibrovascular tissue growth and secondary complications vary widely from case to case. However, the structural pathogenesis of this disease process is consistent because the abnormal tissue nearly always grows along the posterior vitreous surface. Therefore, differing topographic features and secondary complications are dependent on: (1) the places of origin and amount of fibrovascular proliferation, and (2) the location and extent of any posterior vitreous separation. The latter influences the configuration of the fibrovascular tissue growth and determines the effect on the underlying and adjacent retina. Surgical treatment of proliferative diabetic retinopathy is based on this fundamental structural pathophysiology. The -principles of surgery are to minimize damaging effects by reversing the optical and structural complications and preventing recurrence of similar problems. Therefore, the objectives of surgery are to remove any intravitreal opacities and to excise the posterior vitreous surface. To achieve these objectives, various specialized techniques are required, depending on the complexity of the vitreoretinal anatomy in each case. Still, when the objectives are achieved, the operation has similar beneficial immediate and long-term effects in most eyes. This paper discusses and illustrates the structural pathology of proliferative diabetic retinopathy and the principles and methods of surgical therapy, and it presents the results obtained and the complications encountered.

Neovascular Glaucoma Following Pars Plana Vitrectomy for Complications of Diabetic Retinopathy

The patient charts of 81 consecutive vitrectomies performed for complications of proliferative diabetic retinopathy were reviewed. Sixty-five preoperative, intraoperative, and postoperative variables were analyzed. In eyes with completed panretinal photocoagulation, only postoperative retinal detachment had a statistically significant correlation with postvitrectomy development of neovascular glaucoma. Eighty-three percent of eyes with detached retinas, as compared with 4% of eyes with attached retinas, developed neovascular glaucoma (P less than .00001). Aphakia alone did not have a statistically significant effect on the development of neovascular glaucoma; however in the presence of retinal detachment the incidence was very high (92%). Our study shows that a completely attached retina and aggressive panretinal photocoagulation are of paramount importance in decreasing the risk of neovascular glaucoma following vitrectomy for complications of proliferative diabetic retinopathy.

Posterior Chamber Intraocular Lens Insertion During Pars Plana Lensectomy and Vitrectomy for Complications of Proliferative Diabetic Retinopathy

We inserted posterior chamber lenses into 21 eyes with complications of diabetic retinopathy upon completion of pars plana lensectomy and vitrectomy in a single session. After the original surgery, two eyes developed retinal detachments and underwent vitrectomy revisions with scleral buckling, one eye had a fluid-gas exchange for residual vitreous cavity blood, one eye had supplemental laser treatment, and one eye had intraocular antibiotics for endophthalmitis. Six months later, postoperative vision was better in 16 of the 21 eyes (76%), the same in four eyes (19%), and worse in one eye (5%). In 16 eyes visual acuity was 20/200 or better, and in six eyes it was 20/40 or better postoperatively. Decreased vision was caused by preexisting macular disease; two eyes had corneal edema with iris neovascularization associated with residual retinal detachment. The procedure and lenses were well tolerated and provided good pseudophakic vision.

Silicone Oil for Progressive Anterior Ocular Neovascularization After Failed Diabetic Vitrectomy

We have performed revision of vitrectomy and silicone oil injection in 18 eyes that developed advanced iris neovascularization and/or anterior hyaloidal fibrovascular proliferation complicated by retinal detachment or media opacity after vitreous surgery for the complications of proliferative diabetic retinopathy. Stabilization or regression of the anterior ocular neovascular changes was noted in 83% of the eyes. Sustained retinal attachment was achieved in 56% of the eyes, with visual acuity improving to 20/400 or better in 28% of the eyes. Posterior segment vascular and avascular reproliferation was the major cause of anatomic failure, while generalized retinal vascular ischemia was felt to be the principal cause of poor visual results despite retinal attachment. Revision of vitrectomy with silicone oil injection is of limited value in the management of complicated and advanced anterior ocular neovascularization after unsuccessful vitrectomy for diabetic retinopathy.

Extensive argon laser photocoagulation in the treatment of proliferative diabetic retinopathy.

A group of 20 patients (28 eyes) with proliferative retinopathy who required extensive argon laser photocoagulation to induce regression of new vessels is presented. The mean number of burns applied to each eye was 7225, with a maximum of 11,513. These were delivered in a mean of nine sessions over a mean period of 22.9 months. Twenty-five eyes (89%) had a final visual acuity of 6/18 or better. The remaining three eyes (11%) had severely reduced vision attributable to complications of proliferative diabetic retinopathy (traction retinal detachment involving the macula in two eyes and ischaemic maculopathy and a persistent vitreous haemorrhage in the third). Large amounts of confluent argon laser photocoagulation may be necessary for the elimination of new vessels in some patients, and it is our view that laser photocoagulation should be continued until regression of new vessels occurs. This is compatible with the retention of functional vision and good visual acuity.

Results of Vitrectomy for Proliferative Diabetic Retinopathy

The authors treated 1007 eyes with vitrectomy for complications of proliferative diabetic retinopathy. Indications for surgery were: (1) vitreous hemorrhage, 353 eyes (35%); (2) traction retinal detachment, 360 eyes (36%); (3) combined traction -rhegmatogenous retinal detachment, 172 eyes (17%); and (4) 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: (1) vitreous hemorrhage, 48%; (2) traction detachment, 27%; (3) rhegmatogenous detachment, 24%; and (4) progressive fibrovascular proliferation, 46%. The success rate improved in each anatomic category during the last 3 years of the study.

Long-Term Anatomic and Functional Results of Vitrectomy for Diabetic Retinopathy

A long-term follow-up study of 130 eyes that had had initially successful vitrectomies for complications of proliferative diabetic retinopathy showed that only ten (8%) eyes had significant worsening of visual acuity at final examination (18 to 68 months after surgery), compared to the best visual acuity recorded during the first six months after surgery. Active flat retinal neovascularization was present at final examination in only three eyes (2%), and in no case did elevated fibrovascular proliferation occur. The type and incidence of important complications during the early and later postoperative periods indicated a low rate of late complications.