Accelerated ocular neovascularisation in diabetics following posterior chamber lens implantation

Neovascular glaucoma following Nd:YAG laser capsulotomy in a patient with diabetes and syphilitic uveitis

A diabetic woman had been suffering from progressively blurry vision in the right eye for 1 year after cataract surgery. Slit lamp examination revealed bilateral band keratopathy with quiescent anteriorchamber reaction, an intumescent cataract in the left eye, and dense posterior capsular opacity in the right eye. Capsulotomy was performed, but this led to neovascular glaucoma. Because of a refractory elevation in intraocular pressure, trabeculectomy with mitomycin C treatment, vitrectomy with panretinal photocoagulation, and intravitreal injection of bevacizumab were performed. A positive rapid plasma reagin test and a positive Treponema pallidum hemagglutination assay led to the impression of syphilitic uveitis, and the patient was treated with intravenous penicillin for 2 weeks. The visual acuity of the right eye was 0.1 at the 12^th-month follow up. This case shows that neovascular glaucoma may present as a complication of capsulotomy in uveitic/diabetic eyes.

Morphological changes in the anterior segment of the Abyssinian cat eye with hereditary rod-cone degeneration

PURPOSE

The purpose of this study was to investigate morphological changes of the anterior segment of the eye in Abyssinian cats with progressive rod-cone degeneration and to correlate them with blood flow data obtained in the same animals.

METHODS

Sections of the left eyes of six normal cats and of eight cats with different stages of hereditary retinal degeneration were prepared for transmission and scanning electron microscopy. Tangential and sagittal sections were also stained with antibodies against substance P, tyrosine hydroxylase, panneuronal marker PGP9.5, nitric oxide synthase, synaptophysin, and smooth muscle alpha-actin.

RESULTS

In Abyssinian cats with hereditary rod-cone degeneration, significant changes were observed in the iris consisting of irregularities in the vascular wall of smaller arteries without changes in their innervation pattern. The ciliary processes were shorter than in normal cats, and their structure appeared more compact and retracted. Slight changes were also observed in the anterior part of the ciliary epithelium. The anterior chamber angle region did not appear to be affected.

CONCLUSIONS

Clear morphological correlations to the physiological blood flow data were observed in the anterior eye segment, pointing not only to functional but also morphological vascular abnormalities in this animal model for retinitis pigmentosa.

Visual outcome and progression of retinopathy after cataract surgery in diabetic patients

PURPOSE

Diabetes mellitus is a major cause of visual impairment in developed countries through retinopathy and is frequently complicated by cataract formation. The present study examines the visual outcome of cataract surgery in diabetic pat ents.

METHODS

A retrospective study was performed over a 26 month period in a general hospital eye clinic. Eighty-five consecutive diabetic patients who underwent cataract surgery were categorized according to their type of diabetes, duration and treatment, operative technique, pre-operative visual acuity (VA) and degree of retinopathy. Visual acuity and retinopathy status were recorded at a minimum of 4 months postoperatively. Factors affecting visual outcome and progression of retinopathy were then examined.

RESULTS

Of the 107 eyes of the 85 consecutive cases, 55 were without retinopathy (NR), 21 had background retinopathy (BDR), six had background retinopathy with macular oedema (BDR/MO), four had proliferative retinopathy and 12 cases had inadequate fundal view. In the NR and BDR groups, 90 and 81% of patients, respectively, had improved VA compared with 33% of patients with BDR/MO. Retinopathy progressed in 50% of BDR/MO patients compared with progression in 9 and 19% of NR and BDR patients, respectively.

CONCLUSION

The present study illustrates the poor visual outcome in patients with severe, untreated retinopathy, particularly maculopathy, following cataract surgery. Larger prospective studies are needed to better define risk groups and pre-operative treatment strategies.

Iris fluorescein angiography in clinical practice

Iris fluorescein angiography is a valuable technique for elucidating a wide range of eye pathologies, among them developmental anomalies, degenerative disease, retinal vascular occlusions, diabetic microangiopathy, uveitis of various etiologies, glaucoma, tumor, and surgical or accidental trauma. In fact, IFA is more sensitive than biomicroscopy in the evaluation of iris abnormalities. Moreover, it provides indirect but reliable information on the retinal circulation when this cannot be examined directly. Some of the most important clinical applications involve the early detection of iris new vessels, cataract management in diabetic patients, and monitoring of iris tumors. Equipment, procedures, and fluorescein angiography patterns in normal and disease states are described and extensively illustrated. More widespread use of this valuable technique is encouraged.

Progression of diabetic retinopathy and rubeotic glaucoma following cataract surgery

There has been recent interest in the progression of diabetic retinopathy following extracapsular cataract extraction (ECCE) especially with vitreous loss. It is well known that diabetic retinopathy progresses after intracapsular cataract extraction (ICCE) but was thought to be less common after ECCE. We present 7 patients with symmetrical non-proliferative diabetic retinopathy who underwent ECCE with intraocular lens (IOL) implantation. These patients ranged in age from 56 to 69 years; 2 were insulin-dependent diabetics (IDDM) and 5 non-IDDMs. Rubeosis iridis developed quickly between post-operative outpatient visits despite good diabetic control and a static retinal picture in the fellow eye. Visual loss following the onset of rubeosis was severe, with 3 patients needing cyclocryotherapy and eventually having no perception of light. The rapid onset of rubeosis between post-operative outpatient visits leads us to suggest much shorter periods between reviews than is current practice and the consideration of routine panretinal photocoagulation in the immediate post-operative period in diabetics with worsening retinopathy after ECCE and IOL. Possible causes of the increase in neovascularisation and rubeosis are discussed. The most important message highlighted by these case histories is that the surgery and follow-up of diabetic patients undergoing surgery should be undertaken by an ophthalmologist with an interest in diabetes. Where there is no recognised diabetic retinal specialist in a unit, then early referral to such an ophthalmologist is recommended when complications arise.

Visual acuity following extracapsular cataract extraction in diabetes: a meta-analysis

Although pre-operative retinopathy severity appears to be a major factor in determining the visual outcome of diabetic extracapsular cataract extraction, its precise relationship to post-operative visual acuity is ill defined. A meta-analysis was therefore carried out, and studies were included if pre-operative maculopathy and retinopathy status was sufficiently defined to permit discrimination of visual outcome between subgroups. Weighted mean proportions of eyes achieving a post-operative visual acuity > or = 6/12 were as follows: no retinopathy, 87%; non-proliferative retinopathy with no maculopathy, 80%; quiescent proliferative retinopathy with no maculopathy, 57%; non-proliferative retinopathy with maculopathy, 41%; quiescent proliferative retinopathy with maculopathy, 11%; active proliferative retinopathy, 0. Differences in visual outcome between groups were significant (chi 2 = 119.9, p < 0.0005), attributable mostly to the trend across groups (chi 2 for trend = 115.4, p < 0.0005). Logistic regression indicated that maculopathy was a more potent predictor of post-operative visual acuity < or = 6/12 (odds ratio 6.4, 95% CI 4.13-9.94, p < 0.0005) than quiescent proliferative retinopathy (odds ratio 3.33, 95% CI 2.04-5.42, p < 0.0005). The severity of retinopathy and maculopathy prior to cataract surgery in diabetics are the major determinants of post-operative visual acuity. Further study of the relationship between pre-operative retinopathy severity and the incidence of post-operative complications, progression of retinopathy and maculopathy is required to optimise the management of cataract in diabetes.

Relation between iridopathy and retinopathy in diabetes

In order to assess the relation between diabetic iridopathy (DI) and retinopathy (DR), 225 eyes of 117 diabetics with clear media were evaluated. Each patient underwent iris and retinal fluorescein angiography, which was used to classify DI and DR. DI was classified as: absence of DI; non-proliferative DI; proliferative DI; neovascular glaucoma. DR was classified as: absence of DR; background DR; pre-proliferative DR; proliferative DR. The sensitivity of iris fluorescein angiography in assessing DR was 44.5%, the specificity 88%, the positive predictive value 92.8%, and the negative value 31.2%. In pre-proliferative and proliferative DR, fluoroiridographic detection of iris neovessels gave a sensitivity of 56% and a specificity of 100%. The positive predictive value was 100% and the negative value 65%. In conclusion, iris fluorescein angiography yields valuable information on DR and is a helpful basis for avoiding complications when scheduling eyes with dioptric media opacities for surgery.

Pathogenesis of diabetic retinopathy--the missing link?

Release of angiogenic factors in response to the ischaemic retina is currently the most favoured hypothesis for the pathogenesis of proliferative diabetic retinopathy. Reducing the stimulus for angiogenesis by destroying the ischaemic retina also forms the basis of the most effective treatment of diabetic retinopathy by photocoagulation. Though ischaemia is undoubtedly important for neovascularization, there is recent evidence which cast doubts on ischemia being the sole mechanism for diabetic retinopathy. Many clinical observations viz. the protective effects of glaucoma, myopia, unilateral carotid stenosis on diabetic retinopathy; and its worsening after cataract extraction are not adequately explained by the present hypothesis. Moreover, the recent in vitro culture studies on retinal pigment epithelial cells have suggested an alternative explanation for the effectiveness of photocoagulation in proliferative diabetic retinopathy. Furthermore, hyperglycemia has been strongly correlated with the incidence and progression of diabetic retinopathy, but has only been indirectly indicted in its pathogenesis. These facts can be integrated into a more plausible hypothesis for the pathogenesis of diabetic retinopathy. It is hypothesized that a relative reduction in intra-ocular pressure caused by persistent or intermittent hyperglycemia may be the missing link that induces certain morphological changes in the retinal pigment epithelium. These changes, in addition to the ischaemic retina, may be important for the pathogenesis of diabetic retinopathy. Such a hypothesis also explains most of the hitherto unexplained features of diabetic retinopathy.

Plasma glucose levels, postoperative complications, and progression of retinopathy in diabetic patients undergoing intraocular lens implantation

Of 220 patients (250 eyes) who underwent extracapsular cataract extraction with implantation of a posterior chamber intraocular lens, 36 (45 eyes) with non-insulin-dependent diabetes mellitus had no retinopathy, simple, or preproliferative retinopathy. They were divided into group A patients who underwent diet therapy or were treated with oral agents and group B patients who were given insulin therapy. The 184 patients (205 eyes) without diabetes mellitus served as control (group C). Transient elevation of intraocular pressure and cystoid macular edema were observed more frequently in diabetic patients (groups A and B). Progressive retinopathy occurred more frequently in group B than in group A patients, and it correlated with increased levels of plasma glucose. Unilateral cataract surgery was performed on 27 diabetic patients. Nine (33%) operated eyes showed progressive retinopathy, while one (4%) fellow eye worsened. It is possible that both increased levels of plasma glucose and surgical procedures may participate in the progression of retinopathy.

Biomicroscopy versus fluorescein angiography of the iris in the detection of diabetic iridopathy

Iris fluorescein angiography is not commonly employed in clinical practice, but it is the most sensitive technique for the evaluation of iris vessel abnormalities. We used iris fluorescein angiography as the gold standard against which to test the ability of iris biomicroscopy to demonstrate diabetic iridopathy (DI). One hundred and fourteen eyes of 63 diabetic patients affected by preproliferative or proliferative diabetic retinopathy (DR) (the DR groups at high risk of developing DI) were considered. The DI fluorangiographic classification used was: (1) absence of DI; (2) nonproliferative DI; (3) proliferative DI. The sensitivity of biomicroscopy in detecting DI turned out to be 57%, while the specificity was 94%. The positive predictive value was 93% and the negative predictive value 50%. Our study proved that biomicroscopy can accurately judge when DI is absent. When it is present, however, there is a high probability that biomicroscopy will be less precise in the detection of iris lesions.

Extracapsular cataract extraction with placement of a posterior chamber lens in patients with diabetic retinopathy

PURPOSE

The authors evaluated factors that might influence the outcome of extracapsular cataract extraction with placement of a posterior chamber lens in patients with diabetic retinopathy. The factors included patient age and sex, severity of the retinopathy, preoperative laser photocoagulation, vitrectomy, and posterior capsulotomy.

METHODS

The records of 109 patients who had been examined by the authors before cataract surgery were retrospectively reviewed.

RESULTS

The final visual acuity in only 48% of the eyes was 20/40 or better, and 28% had 20/200 or worse visual acuity. Only 65% had an improvement in visual acuity of two or more Snellen lines. Eyes with preoperative macular edema had a poorer visual outcome than eyes without. Macular edema and ischemia accounted for 70% of the eyes with a final visual acuity of 20/50 or worse. The authors found that age was a strong predictor of final visual acuity and chances of improvement. In patients 63 years of age and younger, 58% had 20/40 or better and 81% had improved visual acuity. In patients 64 years of age and older, only 38% had 20/40 or better and only 54% were improved. Supplementary panretinal photocoagulation was required in 37% of patients who had received it preoperatively. Neovascularization of the iris developed in 6% of patients. Posterior capsulotomy did not cause an increased incidence of neovascularization of the iris or in the development or progression of proliferative retinopathy or macular edema.

CONCLUSION

The prognosis of patients with diabetic retinopathy about to undergo cataract surgery, even extracapsular cataract extraction with placement of a posterior chamber lens, is guarded.

Extracapsular cataract extraction in proliferative diabetic retinopathy

PURPOSE

To establish the visual prognosis, prevalence of complications, and optimal strategy for management of proliferative diabetic retinopathy (PDR) in isolated extracapsular cataract extraction (ECCE).

METHOD

This is a retrospective review of 56 patients with PDR who underwent ECCE with lens implantation. Results were compared with 64 patients with background diabetic retinopathy (BDR) operated on during the same time period.

RESULTS

Final visual acuity (67% > or = 20/40) was better in BDR eyes compared with PDR eyes (21% > or = 20/40; P < 0.001). In eyes without maculopathy, 94% with BDR achieved a final visual acuity of at least 20/40 compared with 52% with quiescent proliferative retinopathy (P < 0.001). Final visual acuity in eyes with maculopathy was better in BDR eyes (36% > or = 20/40) than in PDR eyes (5% > or = 20/40) (P < 0.02). No patient with active proliferative or preproliferative retinopathy achieved a final visual acuity of more than 20/80. Postoperative deterioration of retinopathy occurred in 50% of patients with active proliferative retinopathy compared with 10% with quiescent proliferative retinopathy (P < 0.01) and 3% with BDR (P < 0.001). Immediate postoperative fibrinous anterior uveitis, which prevented early panretinal photocoagulation, developed in over half the patients with active proliferative retinopathy.

CONCLUSIONS

Final visual acuity after cataract extraction in diabetic patients with proliferative retinopathy is generally poor; however, in patients with quiescent proliferative retinopathy and no maculopathy, visual acuity may be good. Active proliferative retinopathy at the time of surgery is a poor prognostic indicator for final visual acuity and is associated with postoperative deterioration of retinopathy and fibrinous uveitis, which may preclude immediate postoperative panretinal photocoagulation.

Extracapsular cataract extraction in diabetics with rubeosis iridis

We reviewed thirteen operated eyes (twelve diabetic patients) with rubeosis iridis who underwent extracapsular cataract extraction and intraocular lens implantation. Prior to surgery five had active proliferative retinopathy (APR), and eight had non-proliferative retinopathy (NPR), either quiescent proliferative retinopathy (QPR) or background retinopathy (BR). No case with APR was visually improved by surgery. Three cases with NPR achieved a visual acuity of 6/12. After surgery, vitreous haemorrhage or progression of proliferative retinopathy occurred in three cases with APR. Early postoperative fibrinous uveitis was severe in eyes with APR, resulting in permanent fibrin membrane formation in four. We suggest a significant prognostic indicator in diabetic cataract extraction with rubeosis iridis is the status of the underlying retinopathy. With NPR, postoperative visual acuity may be good and early postoperative complications less severe. In the presence of APR the visual outcome is poor, progression of retinopathy likely and early postoperative fibrinous uveitis may be severe enough to prevent postoperative panretinal photocoagulation. Maximum preoperative panretinal ablation is essential in these cases.

The course of diabetic retinopathy following cataract surgery in eyes previously treated by laser photocoagulation

The course of diabetic retinopathy following extracapsular cataract extraction with posterior chamber lens implantation in eyes previously treated by laser photocoagulation for diabetic retinopathy was retrospectively studied in 33 eyes (33 patients). In 20 eyes (61%) there was no change in the retinal status postoperatively. In 13 (39%) there was postoperative progression of diabetic retinopathy compared with the fellow non-operated eye, in which progression occurred in nine eyes (27%). The severity of the preoperative status affected the incidence of progression. Four eyes (12%) developed complications of diabetic retinopathy--that is, rubeosis iridis and vitreous haemorrhage--which regressed after lasering. Cystoid macular oedema developed in 13 eyes (39%) and its incidence varied according to the postoperative course of diabetic retinopathy. The majority of the eyes showed a postoperative improvement in vision.

Posterior chamber intraocular lens implantation in eyes with inactive and active proliferative diabetic retinopathy

We reviewed the records of 2,100 consecutive eyes that had undergone extracapsular cataract extraction with intraocular lens implantation between January 1981 and December 1989. Of these eyes, 21 had inactive and four had active proliferative diabetic retinopathy at the time of cataract extraction. Twenty-one eyes with inactive proliferative diabetic retinopathy received extracapsular cataract extraction with posterior chamber intraocular lens implantation, and four eyes with active proliferative diabetic retinopathy had both extracapsular cataract extraction with posterior chamber intraocular lens implantation and pars plana vitrectomy with endophotocoagulation. The mean follow-up period was 27 months. Final visual acuity was 20/40 or better in 12 of 25 eyes (48%). Of 25 eyes, five (20%) showed progression of the retinopathy after the operation, and two (8%) developed macular edema. Extracapsular cataract extraction and posterior chamber intraocular lens implantation was well tolerated in most eyes.