One-year results of photodynamic therapy for small predominantly classic choroidal neovascular membranes secondary to age-related macular degeneration.

PURPOSE: To determine the visual and angiographic outcomes of patients with small predominantly classic choroidal neovascular membranes (CNV) undergoing photodynamic therapy (PDT). METHODS: The subjects were a cohort of patients with age-related predominantly classic CNV with lesion size of greatest linear diameter of 2000 microm or less treated with PDT. Lesion size and visual acuity were recorded at baseline and at 3-month intervals. Visual treatment failure was defined as either loss of at least 15 letters or visual acuity less than 35 letters on a modified Early Treatment Diabetic Retinopathy Study chart. Lesion treatment failure was defined as increase in greatest linear diameter (GLD) of at least 500 microm. RESULTS: Twenty-five eyes of 25 patients were included. Visual treatment failure occurred in 16 and mean visual acuity dropped from 58 letters to 34 letters (p<0.0001). In 11 of these patients this occurred within the first 3 months. Lesion treatment failure occurred in 18 patients. Mean GLD increased from 1331 to 2935 microm (p<0.0001). Early growth of the lesion was associated with poor visual outcome with growth in GLD in the first 3 months of 310 microm in patients without eventual visual treatment failure and 1131 microm in patients with eventual visual failure (p=0.027). CONCLUSIONS: Small predominantly classic lesions commonly cause visual deterioration if treated with PDT alone. In the first year over 50% may lose at least 15 letters or drop below 35 letters, with most visual loss occurring in the first 3 months. Visual loss is associated with early lesion growth.

Changes in chromatic and achromatic contrast sensitivities following tropicamide administration.

PURPOSE: To investigate the effects of tropicamide on chromatic and achromatic contrast sensitivities over the physiological range of spatial frequencies. METHODS: A total of 26 healthy volunteers, with a mean age of 32 years, were examined with and without one drop of 1% tropicamide being administered 30 min previously. On each occasion, acuity and pupil diameter were recorded, and chromatic and achromatic contrast sensitivities were examined using the Sussex Grating Machine. RESULTS: Following tropicamide administration mean pupil diameter increased from 4.1 mm to 7.2 mm (P<0.001), and mean BCVA was reduced by 0.07 LogMar units (P<0.001). Achromatic contrast sensitivity was significantly reduced following tropicamide administration at 2.20 cycles per degree (cpd) (P=0.01), 3.40 cpd (P=0.01), 10 cpd (P=0.04), 17 cpd (P=0.04), and 25 cpd (P<0.01). There was no difference in contrast sensitivity at lower spatial frequencies (0.33 and 0.66 cpd). Chromatic contrast sensitivity was not significantly altered when tested along the red-green and tritan confusion axes. CONCLUSIONS: Achromatic contrast sensitivity is significantly reduced following tropicamide administration at intermediate and high spatial frequencies. No significant changes were seen at low spatial frequencies and in chromatic contrast sensitivities.

Vitreous haemorrhage without obvious cause: national survey of management practices.

AIM: We undertook a national survey to establish the management of dense vitreous haemorrhage without obvious cause. METHODS DESIGN: Cross-sectional anonymous self-reporting survey of ophthalmic practitioners within three target groups: vitreoretinal specialists (VRS), nonvitreoretinal specialists (NVRS), and associate specialists (AS). INTERVENTION: Presentation of the hypothetical scenario of a patient presenting with recent onset (fresh) vitreous haemorrhage with no retinal view and no apparent cause on history taken at presentation. OUTCOME MEASURES: The relative importance assigned by respondents to eight examination techniques at presentation. The proportion of respondents stating that they would review patients and perform B-scan examination at or prior to 2 weeks after presentation. The stated time to surgical intervention by VRS, and the time to referral by NVRS and AS. RESULTS: VRS ranked B-scan examination higher than AS (P<0.001). A total of 98.1% of VRS indicated that they would next review patients within 2 weeks of presentation, this figure fell to 86.5% for NVRS and 47% for AS (P<0.001). A 98.1% of VRS indicated that they would next perform B-scan ultrasound within 2 weeks of presentation, this figure fell to 88.9% for NVRS and 70.6% for AS (P<0.001). The mean time to surgical intervention by VRS was 9.5 weeks without retinal tear demonstrated on B-scan, 1.7 weeks with retinal tear demonstrated on B-scan and 1 week with retinal detachment demonstrated on B-scan. The mean time to referral by NVRS was 6.7 weeks and by AS was 11.9 weeks. CONCLUSIONS: Vitreoretinal specialists considered B-scan the most important examination tool, and typically perform B-scan early and frequently after presentation. Non-VR ophthalmologists (particularly associate specialists) review patients and perform B-scan ultrasound later and less often than vitreoretinal specialists. We recommend early referral to VR specialists, as reported referral even in uncomplicated cases would often be outside the timeframe within which VR specialists would typically choose to operate.

Surgical management of iris defects with prosthetic iris devices.

PURPOSE: To evaluate the safety and efficacy of surgical implantation of prosthetic iris devices in patients with iris deficiency. METHODS: Nine patients with traumatic iris defects, congenital aniridia or iris coloboma, and surgical or optical iridectomies were included in a noncomparative case series. Cataract surgery with intraocular lens and prosthetic iris implantation was performed in 10 eyes. The visual acuity, subjective degree of glare disability, postoperative anatomic results, and intraoperative and postoperative complications were evaluated. RESULTS: The mean follow-up was 17.75 months (range 4-48 months). Best-corrected visual acuity improved in nine of 10 eyes (90%) and remained unchanged in one eye. Glare subjectively improved in four of five eyes (80%) of patients complaining of glare preoperatively. All eyes achieved the desired anatomic result. Intraoperative complications included one anterior capsular tear. Postoperative complications included a short period of mild postoperative anterior uveitis in four eyes. Secondary glaucoma was absent. CONCLUSION: In patients with iris deficiency, implantation of prosthetic iris device, and intraocular lens implant following cataract surgery appears to be safe and effective in reducing glare disability and improving visual outcomes.

Retinal dialysis: are we missing diagnostic opportunities?

AIMS: To review medical records of those patients managed by our department for retinal dialysis, and establish whether the initial assessment had been adequate to make the diagnosis. That is, to establish if an adequate initial assessment had been performed that would reasonably exclude the likelihood of retinal dialysis and other trauma-related sequelae such as angle recession. METHODS: A retrospective review was made of all patients managed for retinal dialysis at Sussex Eye Hospital between 20 March 1997 and 20 September 2002 (66 months). In addition to general demographic data, surgical management and outcome, patient files were reviewed for history of trauma, prior ophthalmic review, and whether such review included documentation of peripheral retinal examination and gonioscopy. RESULTS: A total of 580 primary procedures were performed for retinal detachment during the review period, of which 32 eyes of 29 patients underwent surgery for retinal dialysis (6%). There were 21 male and eight female patients, with a history of trauma obtained in 55% (17 eyes, 16 patients). Of the 16 patients with prior trauma, nine had undergone prior ophthalmic review at the time or soon after their trauma; however, only 2 (22%) had documented evidence of indented peripheral retinal examination. Only one (3%) patient in the whole series had documented gonioscopy. CONCLUSIONS: Patients with history of trauma often present at the time or soon after their injury (eg hyphaema, orbital fractures). Thus, an opportunity exists to screen patients for known sequelae of trauma such as retinal dialysis and angle recession. It was disappointing to learn that this opportunity was not always being utilized, with some patients consequently developing macula-off retinal detachments and potential for reduced visual outcome.

Clinical outcome following cataract surgery in very elderly patients.

PURPOSE: The number of very elderly patients waiting for cataract surgery is predicted to increase. The aim of our study was to determine the clinical outcome following cataract surgery in this age group. METHODS: In this retrospective study, patients aged 96 years and above, who underwent cataract surgery between June 1993 and January 2001, were identified. Clinical data were retrieved from their medical records. Living patients were further invited for clinical examination. RESULTS: In all, 34 eyes of 21 patients (20 females) were identified. Six patients were deceased. In total, 30/34 eyes had phacoemulsification and four had extracapsular extraction. Preoperative vision was or=6/60 in 25/34 eyes (73.53%), >or=6/18 in 21/34 eyes (61.76%), and >or=6/9 in 10/34 eyes (29.41%). Visual acuity improved in 24/34 eyes (70.59%) and remained the same in 6/34 eyes. Complications included anterior capsule tear (three), zonular dialysis with vitreous loss (one), posterior capsule rupture with vitreous loss (one), incarceration of iris to paracentesis wound (two), postoperative uveitis (two), and posterior capsular opacification (19). In all, 7/34 eyes had undergone YAG capsulotomy. CONCLUSION: Surgeons should not be deterred from offering cataract surgery to the very elderly as successful visual rehabilitation is the norm. A further prospective multicentre study is required to confirm the benefits and assess the risks of cataract surgery in this age group.

Assessment of colour vision as a screening test for sight threatening diabetic retinopathy before loss of vision.

AIM: To assess the effects of sight threatening diabetic retinopathy (STDR) on colour vision and to evaluate automated tritan contrast threshold (TCT) testing for STDR screening before significant visual loss. METHOD: Patients were recruited from a hospital based photographic screening clinic. All subjects underwent best corrected Snellen visual acuity (BCVA) and those with 20/30 vision or worse were excluded. Automated TCT was performed with a computer controlled, cathode ray tube based technique. The system produced a series of sinusoidal, standardised equiluminant chromatic gratings along a tritan confusion axis. Grading of diabetic retinopathy was made by one of the team of experienced ophthalmic registrars (SpR) using slit lamp biomicroscopy and a 78D lens; HbA(1c) and urine albumin were also tested. RESULTS: Patients with STDR had significantly worse TCT despite normal BCVA (p<0.0001). TCT yielded a sensitivity of 100% for detecting diabetic maculopathy and 94% for STDR with a specificity of 95%. Logistic regression analyses showed that TCT (p<0.001) and HbA(1c) (p<0.05) correlated significantly with the presence of STDR but duration of diabetes, urine albumin counts, and BCVA failed to show any significant correlation. No associations between TCT and duration of disease, TCT and HbA(1c), and TCT and urine albumin counts were found. CONCLUSION: Tritan colour vision deficiency was observed in patients with STDR despite their normal BCVA. These results indicate that automated TCT assessment is an effective and clinically viable technique for detecting STDR, particularly diabetic maculopathy, before visual loss.

Effectiveness of apraclonidine 1% in preventing intraocular pressure rise following macular hole surgery.

AIM: To determine the efficacy of apraclonidine hydrochloride 1% in preventing intraocular pressure (IOP) spikes following idiopathic macular hole (IMH) surgery with platelet adjunct and intraocular gas tamponade. METHODS: This is a prospective, double masked, randomised study to compare apraclonidine hydrochloride 1%, an alpha(2) agonist, with a placebo in the prevention of IOP rises following macular hole surgery. Each patient was randomly selected to receive either the study drug or the placebo; one drop was instilled in the conjunctival sac 2 hours preoperatively and on completion of the procedure. IOP was measured at baseline and at 1, 3, 6, 24, 48 hours, and 2 weeks postoperatively. Blood pressure and heart rate were also recorded at baseline and at 3 and 24 hours postoperatively. Macular hole repair surgery was performed as standardised in the unit with a vitrectomy, platelet concentrate, and complete fill of the vitreous cavity with perfluoropropane gas (C(3)F(8)) at a concentration of 16%. RESULTS: 25 patients (26 eyes) were enrolled. 12 eyes received apraclonidine hydrochloride 1% (mean age 70.7; range 62-78 years) and 14 eyes received the placebo (mean age 70.0; range 57-81 years). At baseline evaluation the mean IOP was 15.6 mm Hg for the study group and 14.3 mm Hg for the placebo group. The mean postoperative IOP at 1 hour, 3 hours, 6 hours, and 24 hours was 10.6, 9.6, 8.2, and 14.0 mm Hg in the apraclonidine group. In the control group at the same time intervals the mean IOP was 23.4, 17.5, 19.2, and 24.7 mm Hg. These readings were statistically significant different: 1 hour (p=0.0001); 3 hours (p=0.0015); 6 hours (p<0.0001); and 24 hours (p=0.019), the readings at 48 hours and 2 weeks were not statistically significant different (p=0.15 and p=0.59). Only one of the patients in the study group had an IOP above 25 mm Hg at any time. In the control group an IOP above 25 mm Hg was found in seven patients (50%) at the 1 hour postoperative measurement. At 2 weeks the IOP was recorded below 25 mm Hg in all patients. No statistically significantly difference was noted between the two groups regarding the systolic or diastolic blood pressure values and the heart rate records. No local or systemic adverse reactions were observed. CONCLUSIONS: Apraclonidine hydrochloride 1% appears to be an efficacious and safe drug in the prophylaxis of early postoperative IOP elevations in patients undergoing macular hole surgery.

Chromatic contrast thresholds as a prognostic test for visual improvement after macular hole surgery: color vision and macular hole surgery outcome.

PURPOSE: To evaluate the relationship between preoperative chromatic contrast thresholds, postoperative visual acuities (VA), and visual improvement after macular hole surgery. METHODS: A consecutive series of patients with Stage II to IV macular holes was studied before macular hole surgery. Preoperative chromatic contrast thresholds, VA, and reading acuity were analyzed in relation to the postoperative visual function. The chromatic contrast thresholds were measured using a computerized cathode ray tube-based system along red-green and tritan confusion axes. RESULTS: Preoperative and postoperative chromatic contrast thresholds were elevated significantly in affected eyes (P < 0.001). Preoperative VA showed a strong correlation with postoperative VA (r = 0.66, P < 0.001) but a weak correlation with visual improvement (r = -0.33, P = 0.03). Red-green contrast threshold correlated strongly with both the distance visual improvement (r = -0.77, P < 0.001) and reading visual improvement (r = -0.61, P < 0.001). Tritan contrast threshold, however, showed a slightly weaker correlation (distance: r = -0.63, P < 0.001; reading: r = -0.47, P < 0.005). CONCLUSIONS: These results suggest that chromatic contrast thresholds, especially the red-green contrast threshold, represent a better prognostic guide for visual improvement after macular hole surgery than VA measurement.

Clinical evaluation of 'local contrast enhancement' for oral fluorescein angiograms.

PURPOSE: To describe and assess the clinical impact of 'local contrast enhancement' on oral fluorescein angiograms. METHODS: Oral fluorescein angiograms (OFA) were performed on 12 patients with a range of diabetic retinopathy. The digital images were processed using two enhancement techniques: histogram equalization, a widely available method; and 'local contrast enhancement'. Twelve control images and 24 enhanced images were randomised and subjectively graded for clarity between 1 and 100 on a visual analogue scale by two masked observers. A score of 50% was chosen as the cut-off for clinically useful images. RESULTS: The mean score for the unenhanced images was 38.8% (SD 19.4); the histogram equalization performed better at 54.7% (SD 10.0) (p = 0.016) and 'local contrast enhancement' at 69.4% (SD 13.6) (p < 0.001). These results equate to a 14.7% improvement in comparison with histogram equalization and a 30.3% improvement with the 'local contrast enhancement' technique. All the 'local contrast enhancement' images were clinically useful, compared with 58.3% of the histogram equalization images (chi 2 2.08, p = 0.2), and 33.3% of the control images (chi 2 = 6.75, p = 0.01). CONCLUSION: This pilot study has demonstrated the power of 'local contrast enhancement' techniques for low-contrast fluorescein angiograms. Using 'local contrast enhancement' oral fluorescein angiograms can give high-quality images and may allow safer patient investigation.

Screening for CMV retinitis using chromatic discrimination thresholds and achromatic contrast sensitivity.

BACKGROUND: Many patients with cytomegalovirus retinitis (CMVR) are unaware of visual disturbance so screening is advocated for patients with HIV and low CD4 counts. Many tests of retinal function have been recommended but few are effective at detecting CMVR. We assess the potential of chromatic discrimination thresholds and achromatic contrast sensitivity as screening tests for patients with CMVR. METHOD: 11 HIV+ patients with CMVR, 16 age matched HIV+ patients, and 29 age matched controls were recruited. Visual acuity, chromatic discrimination thresholds, and achromatic contrast sensitivity were measured. Fundal examination was performed by slit lamp biomicroscopy for HIV+ patients. Those with CMVR were photographed and the CMVR graded from the photographs. RESULTS: Loss of chromatic discrimination was found in patients with CMVR (tritan p<0.0005, red/green p<0.05). The same group had deterioration in achromatic contrast sensitivity at 2.2, 3.4, and 10 cpd (p<0.05). There was correlation between the zone of CMVR with chromatic gratings (tritan r=0.83, p<0.005). No statistically significant difference was found between the HIV+ patients and the controls for all tests (p>0.1). CONCLUSIONS: HIV+ patients with CMVR have a loss of chromatic discrimination and achromatic contrast sensitivity and this may be used to screen HIV+ patients for CMVR.

Vitrectomy for phacolytic glaucoma in a patient with homocystinuria.

PURPOSE: To determine the successful treatment of unilateral phacolytic glaucoma by vitrectomy and trabeculectomy in a patient with homocystinuria whose lens had dislocated into the vitreous at least 15 years earlier. METHODS: In a 32-year-old woman with homocystinuria, bilateral dislocation of the lens into the vitreous, and phacolytic glaucoma in her left eye a three-port pars plana vitrectomy was performed with the patient under general anesthesia. The lens was removed and a trabeculectomy fashioned. Special precautions for general anesthesia included preoperative aspirin and compression stockings for thromboembolic prophylaxis and intraoperative dextrose infusion, 5%, to maintain intravascular volume and prevent hypoglycemia. RESULTS: The intraocular pressure and uveitis resolved postoperatively with improvement in the visual acuity and intraocular pressure, which returned to normal without further treatment. CONCLUSIONS: Phacolytic glaucoma is best resolved by removal of the exciting lens material. Pars plana vitrectomy with the patient under general anesthesia can be carried out safely despite the risks traditionally associated with homocystinuria.

What effect does laser photocoagulation have on driving visual fields in diabetics?

Although laser panretinal photocoagulation (PRP) for proliferative diabetic retinopathy is known to cause peripheral field constriction, the risks of failing the UK driving field test following treatment are currently unclear as the small number of previous studies have conflicting results. Following PRP using only argon laser with a 500 microns spot size, both uniocular and binocular Esterman visual fields from 60 diabetic patients were assessed by the Chairman of the Visual Standards Sub-Committee of the Royal College of Ophthalmologists. Forty-two per cent of uniocular fields from treated eyes failed. Twelve per cent of binocular fields from those having bilateral PRP failed. Type II diabetes was associated with a significant increase in the risk of failure. Although there is a high risk of failure in any given treated eye, 88% of diabetics will pass a binocular field test, even if both eyes are treated.

How good are we at assessing driving visual fields in diabetics?

PURPOSE/BACKGROUND: Following laser panretinal photocoagulation (PRP) for proliferative diabetic retinopathy, patients are at risk of failing the UK driving visual field test due to loss of peripheral field. Although a definition of the minimum field requirement exists, differences in its interpretation may influence whether fields pass or fail. Currently it is not known how fields are interpreted in practice nor to what extent this affects failure rates. METHODS: Uniocular and binocular Esterman visual fields from 60 diabetic patients following PRP were examined both by the chairman of the Visual Standards Sub-Committee of the Royal College of Ophthalmologists and separately by four consultant ophthalmologists. The results were analysed (1) to assess the extent of agreement and (2) to identify, from the chairman's results, the field deficits that are still compatible with passing. RESULTS: Agreement was generally good for binocular fields but was only moderate for uniocular fields. In up to 15% of binocular fields and 43% of uniocular fields the chairman's decision was different from that of the consultants. Several key aspects of the field that influence a pass/fail decision are identified. CONCLUSIONS: Substantial differences in the assessment of driving visual fields following RPR currently exist between consultants and the chairman of the Visual Standards Sub-Committee. Using the information presented here to guide assessment it is now possible to reduce this variation.

Chromatic-contrast threshold impairment in diabetes.

A prospective study was carried out to investigate acquired colour-vision deficits in diabetics using an automated, computer-controlled, cathode-ray-tube based test of chromatic contrast. Chromatic-contrast thresholds estimates were measured along both a red/ green (constant S-cone) confusion axis and a tritan (constant M/L-cone) confusion axis for 305 eyes of 305 diabetics. The diabetic data were partitioned into groups based on a clinical categorisation of retinopathy. The diabetic data were compared with both age-matched and 'lens-equated' control data obtained from a bank of 347 normal subjects. Further analysis of differences between diabetic-status groups was performed. Associations between chromatic contrast threshold estimates and age, duration of disease, and severity of both macular oedema and ischaemia were investigated. The diabetic group was found to have significantly reduced chromatic-contrast threshold estimates when compared with normal controls, even in the absence of retinopathy. This reduction in chromatic contrast was predominantly tritanopic in nature. Interestingly, no reduction in red/green chromatic-contrast threshold estimate was found in diabetics without retinopathy. The tritan deficit seen in diabetics without retinopathy was strongly correlated with duration of disease, but when adjustments were made to account for the effects of duration-dependent lens yellowing, the tritan deficit was no longer apparent. A correlation between both the severity of macular oedema and severity of ischaemia with chromatic-contrast loss was established. Acquired reductions in both red/green and tritan chromatic-contrast threshold estimates seen in diabetics are strongly correlated with the severity of retinopathy. The results provide evidence that the specific tritan deficits seen in diabetics can be explained by the effects of lens yellowing rather than by selective damage of the blue cone system as has been hypothesised by other groups. The results provide support for the potential use of automated CRT-based tests of colour vision in diabetic retinopathy screening protocols.