Selective blockade of phosphodiesterase types 2, 5 and 9 results in cyclic 3'5' guanosine monophosphate accumulation in retinal pigment epithelium cells.

AIM: To investigate which phosphodiesterase (PDE) is involved in regulating cyclic 3'5' guanosine monophosphate breakdown in retinal pigment epithelium (RPE) cells. METHODS: cGMP content in the cultured RPE cells (D407 cell line) was evaluated by immunocytochemistry in the presence of non-selective or isoform-selective PDE inhibitors in combination with the particulate guanylyl cyclase stimulator atrial natriuretic peptide (ANP) or the soluble guanylyl cyclase stimulator sodium nitroprusside (SNP). mRNA expression of PDE2, PDE5 and PDE9 was studied in cultured human RPE cells and rat RPE cell layers using non-radioactive in situ hybridisation. RESULTS: In the absence of PDE inhibitors, cGMP levels in cultured RPE cells are very low. cGMP accumulation was readily detected in cultured human RPE cells after incubation with Bay60-7550 as a selective PDE2 inhibitor, sildenafil as a selective PDE5 inhibitor or Sch51866 as a selective PDE9 inhibitor. In the presence of PDE inhibition, cGMP content increased markedly after stimulation of the particulate guanylyl cyclase. mRNA of PDE2,PDE5 and PDE9 was detected in all cultured human RPE cells and also in rat RPE cell layers. CONCLUSIONS: PDE2, PDE5 and PDE9 have a role in cGMP metabolism in RPE cells.

Risk factors for redetachment and worse visual outcome after silicone oil removal in eyes with complicated retinal detachment.

PURPOSE: The goal of this study was to identify risk factors for redetachment and/or a worse visual outcome after silicone oil removal (SOR) for complicated retinal detachment. METHODS: The authors retrospectively analyzed 287 consecutive eyes with SOR between January 1999 and December 2003. RESULTS: Anatomic success after SOR was achieved in 81% of the eyes. The overall anatomic success at the end of follow-up was 94%. Postoperative ocular hypertension was found in 8% of the eyes, hypotony in 6% of the eyes, and keratopathy in 29% of the eyes. After SOR 43% of the eyes had an improvement in visual acuity of at least two Snellen lines. After multivariate analysis, male sex, the presence of preoperative rubeosis, and proliferative diabetic retinopathy (PDR) were found to be risk factors for recurrent retinal detachment. Male sex, preoperative visual acuity of <0.1 Snellen lines, PDR, the performance of three more operations, any size of retinectomy, and hypotony were found to be associated with a poor visual outcome of Snellen visual acuity <0.1. CONCLUSIONS: Retinal detachment after SOR in the current unselected series of eyes occurred in approximately 20%, which is comparable to the Silicone Oil Study reports, published approximately 20 years ago. However, preoperative selection was then made, and less than 50% of the silicone oil-filled eyes had SOR. The higher overall anatomic success in the current study may be due to improved vitreoretinal surgical techniques.

Immunological factors in the pathogenesis and treatment of age-related macular degeneration.

Recent findings indicate that immunological factors are involved not only in the pathogenesis of age-related macular degeneration (AMD), but also in its treatment. Earlier data showing the presence of inflammatory cells in affected areas of AMD retinas support this statement. Although a possible role for autoimmunity was initially suggested, it has never reached general acceptance. Microorganisms have also been implied in the pathogenesis of AMD. Both serum antibacterial antibody levels and positive DNA tests from neovascular membranes have pointed to a possible role for Chlamydia pneumoniae in the pathogenesis of AMD. New data is providing evidence for the hypothesis that deposits between Bruch's membrane and the retinal pigment epithelium (RPE) cell layer may act as a stimulus for the local activation of the complement system. This may lead to a further growth of the deposits due to the strong chemotactic activity of certain complement activation products (such as C5a) with an influx of inflammatory cells. The buildup of cells and extracellular deposits may lead to local ischemia resulting in the activation of RPE cells. These activated RPE cells are thought to release angiogenic stimuli leading to choroidal neovascularization, which is the most serious complication of AMD. The fact that immunosuppressive drugs such as triamcinolone acetonide and anecortave acetate are capable of inhibiting choroidal neovascularization is consistent with an inflammatory component in the pathogenesis of AMD. Specific immunotherapy directed at certain cytokines or growth factors is now being investigated at both the animal and patient levels. Various clinical trials involving engineered antibodies are now being applied to block angiogenic factors such as the vascular endothelial growth factor (VEGF). An approach using gene therapy to influence angiogenesis by inducing the production of the pigment epithelium-derived factor (PEDF) was able to block neovascularization in an experimental murine model. Besides trying to block ongoing processes in AMD, retinal transplantation is now also being investigated as a treatment option. The fact that the retina is possibly an immunoprivileged tissue in combination with experimental data showing that the subretinal space is an immunoprivileged site is an indication that transplantation would not suffer from the rejection process. A larger obstacle is the question whether transplanted retinal tissue will regain its functional properties.

Noninvasive assessment of the hydration gradient across the cornea using confocal Raman spectroscopy.

PURPOSE: The feasibility of Raman spectroscopy for the noninvasive assessment of axial corneal hydration was investigated. METHODS: A scanning confocal Raman spectroscopy system, with an axial resolution of 50 microns, was used to assess noninvasively the water (OH-bond) to protein (CH-bond) ratio as a measure of the hydration in collagen-based phantom media and rabbit corneas. RESULTS: Raman spectra with high signal-to-noise ratios were obtained under in vitro and in vivo conditions within a range of corneal hydration (H = 0.0-8.3 mg water/mg dry wt). The Raman intensity ratio OH/CH showed a strong correlation with the hydration of the phantom medium (R2 > 0.99) and the rabbit corneas (R2 > 0.95). A degree of reproducibility was seen in measurements performed at a specific depth within the cornea (SD = 1.2%-2.7%). Quantitatively, the spatially resolved corneal water content, as assessed with our method, showed an increasing gradient from the anterior to the posterior region, with a difference of approximately 0.9. Significant qualitative differences in the axial hydration gradient were observed between the in vitro and in vivo situation, caused by the presence of an intact tear-film in vivo. Characterization of the axial corneal hydration using Raman spectroscopy provided a reliable estimation of total corneal hydration compared with conventional measurements using pachymetry and lyophilization. CONCLUSIONS: The proposed noninvasive confocal Raman spectroscopic technique has the potential to assess the axial corneal water gradient with a degree of sensitivity and reproducibility.

A long-term follow-up study of laser coagulation of neovascular membranes in angioid streaks.

We treated 30 eyes (24 patients) with angioid streaks and neovascular membranes using light coagulation. Of 30 eyes, 16 showed either ameliorated or unchanged visual acuity. Twelve of the remaining 14 eyes retained a visual acuity of 20/200 or better. In 11 patients, the fellow untreated eye showed central macular degeneration with loss of central vision. The follow-up period ranged from two months to 16 years (mean, 3.4 years).

Levels of basic fibroblast growth factor, glutamine synthetase, and interleukin-6 in subretinal fluid from patients with retinal detachment.

PURPOSE: To investigate the presence of basic fibroblast growth factor, glutamine synthetase activity, and interleukin-6 in subretinal fluid from patients with retinal detachment. METHODS: In a prospective study we measured basic fibroblast growth factor, glutamine synthetase activity, interleukin-6, and total protein in subretinal fluid samples from 96 eyes from 94 consecutive patients with a retinal detachment corrected by a conventional scleral buckling operation in our clinical practice. As controls, vitreous fluid samples from eyes with a macular hole (n = 6) or pucker (n = 11) were used. Laboratory data of the patient group were compared with the control group and correlated with various clinical data. RESULTS: Levels (median, range) of basic fibroblast growth factor, glutamine synthetase activity, interleukin-6, and total protein were significantly higher in patients than in controls (P <.0001). An increased level of glutamine synthetase and total protein correlated with a longer duration of the retinal detachment (r =.4, P =.002, and r =.34, P =.001, respectively). Interleukin-6 and basic fibroblast growth factor levels did not correlate with the duration of the detachment. After multivariate logistic regression analysis, no significant relation was found between any of the tested subretinal proteins and a low visual outcome or redetachment. CONCLUSIONS: We found increased levels of basic fibroblast growth factor and glutamine synthetase in subretinal fluid from patients with retinal detachment. Basic fibroblast growth factor and glutamine synthetase may play a role in the pathogenesis and recovery after retinal detachment. The questions of whether the increased levels of basic fibroblast growth factor and glutamine synthetase result from leakage of dying glia cells (including Müller cells) and neurons and if basic fibroblast growth factor is actively produced to protect the photoreceptor cells need further research.

Yellow dye laser thermotherapy of choroidal neovascularisation in age related macular degeneration.

AIM: A pilot study of the feasibility of using dye laser thermotherapy (LTT) at a subcoagulation temperature to occlude newly formed vessels in patients with age related macular degeneration (AMD). METHODS: Choroidal neovascularisation (CNV) in 24 eyes with exudative AMD was treated with a continuous wave yellow laser at 578 nm. Parameters were an exposure time of 2 or 5 seconds, a spot size of 750 or 1000 microm, and a laser power of 100-200 mW. The clinical end point was a greyish discoloration at the treatment site. The effect of thermotherapy was documented by ophthalmoscopic and fluorescein angiographic examination. The follow up after LTT was 4-16 months, mean 5 months. RESULTS: LTT resulted in total occlusion of newly formed vessels in 15 eyes (62.5%). Neovascular outgrowth within 6 weeks and recurrences 2-4 months after LTT were observed, each in three eyes. In six of the nine eyes with occlusion of CNV without recurrence the choriocapillaris remained perfused; in two eyes only the large choroidal vessels remained perfused. In six eyes pigmentary changes were the only ophthalmoscopic and fluorescein angiographic signs of treatment. The effect of LTT is rather unpredictable. CONCLUSION: CNV in AMD can effectively be treated by yellow dye laser thermotherapy with preservation of choroidal perfusion. The technique requires dosimetric adaptation.

Asymmetrical vertical phorias indicating dissociated vertical deviation in subjects with normal binocular vision.

We measured the symmetry of phoria angles in six normal subjects. Subjects were selected on the basis of good visual acuity and stereopsis, normal binocular eye alignment and, apart from mild refraction errors, absence of ocular abnormalities. They were instructed to look at a word on a reading chart at 2 m distance. Each measurement consisted of five subsequent intervals of 5 s duration. During these five intervals viewing was binocular, with the right eye only, binocular, with the left eye only, and binocular, respectively. Each experiment consisted of twelve measurements. Eye movements were measured with scleral coils suited for measuring in horizontal, vertical and torsional directions. Five out of six subjects displayed an asymmetrical vertical phoria; one subject showed an alternating hyperphoria; four displayed a left over right vertical phoria that was largest for left eye occlusion. Only one subject showed a symmetrical vertical phoria. Both the size of the vertical phorias and the size of the asymmetries in these vertical phorias were very small: on average 0.16 +/- 0.01 and 0.17 +/- 0.01 degree, respectively. The direction of the vertical phoria asymmetries (the largest left over right was found with left eye occlusion) and the fact that asymmetries were found more often in vertical than horizontal and torsional phorias suggest that these asymmetries are related to dissociated vertical deviation. These results suggest that dissociated vertical deviation, often observed in subjects with a disruption of binocular vision early in life, reflects the enhancement of a phenomenon that is present in normal subjects as well.

Decreased levels of cGMP in vitreous and subretinal fluid from eyes with retinal detachment.

BACKGROUND: Cyclic guanosine monophosphate (cGMP) is produced in different retinal cells, including photoreceptor cells, wherein cGMP mediates photo-transduction. CGMP is degraded by phosphodiesterases (PDE). The aim was to investigate whether retinal detachment alters intraocular cGMP levels in human eyes. METHODS: cGMP and PDE were determined in vitreous fluid from 50 eyes with a retinal detachment (group I) and in 20 control samples (group II) of vitreous fluid from eyes without retinal detachment. Group III consisted of subretinal fluid samples from 70 eyes with retinal detachment. RESULTS: cGMP in vitreous fluid from eyes with retinal detachment (6.5 (SD 1.7) nM) was decreased compared to controls (67.1 (10.0) nM) (p<0.0001). In subretinal fluid, the mean level of cGMP was 2.4 (0.2) nM. No PDE could be detected in any of the intraocular fluid samples of patients nor controls. A decrease in the mean level of cGMP in subretinal fluid of eyes with retinal detachment correlated with a longer duration of detachment (r = -0.45, p = 0.007). CONCLUSIONS: Retinal detachment was found to be associated with a decrease in vitreous cGMP concentration. In subretinal fluid, a low cGMP level correlated inversely with the duration of the detachment.

Quality of care from the perspective of the cataract patient: the reliability and validity of the QUOTE-cataract.

BACKGROUND/AIMS: To assess reliability and validity of the QUOTE-cataract, a questionnaire that measures the quality of care from the perspective of cataract patients. METHODS: The QUOTE-cataract was tested in a multicentre study among 540 cataract patients in three different hospitals. Reliability was represented by internal consistency (Cronbach's alpha), and repeatability (intraclass correlation coefficient (ICC)). Validity was evaluated qualitatively and by factor analyses. RESULTS: A strong internal consistency coefficient (0.89), and high repeatability (ICC = 0.76) demonstrated good reliability. Content validity was assured by involvement of patients in the development of the questionnaire. Factor analysis confirmed an underlying taxonomy of generic and disease specific items. CONCLUSION: The QUOTE-cataract has good reliability and provides a valid assessment of quality of care in cataract surgery.

Cost effectiveness of foldable multifocal intraocular lenses compared to foldable monofocal intraocular lenses for cataract surgery.

AIM: To analyse the cost effectiveness of foldable monofocal intraocular lenses (IOLs) compared to foldable multifocal IOLs in cataract surgery alongside a prospective, multicentre randomised clinical trial (RCT). METHODS: Patients underwent cataract surgery with bilateral monofocal (n = 97) or multifocal (n = 93) IOL implantation. Cost data and patient preferences, using the visual analogue scale (VAS), the time trade-off (TTO), and the standard gamble (SG) technique were obtained preoperatively and postoperatively by structured interviews. The incremental costs (multifocal minus monofocal), mean costs per patient, and differences in preferences were computed. RESULTS: Mean costs for glasses per patient in the monofocal group were 41.67 and in the multifocal group 149.58. The difference in costs between the multifocal and monofocal group was -92.09 and was statistically significant (p = 0.008). No significant differences were found in total costs or in effectiveness between the monofocal and multifocal IOL group. CONCLUSION: The cost effectiveness of multifocal IOLs is reduced to a cost minimisation analysis, because of the inability to demonstrate significant differences in effects. The use of multifocal IOLs in cataract surgery resulted in a significant reduction in costs for patient's postoperative spectacles.

Identification of intraocular lens materials using confocal Raman spectroscopy.

PURPOSE: To develop and test a noninvasive method to identify intraocular lens (IOL) materials in vitro. SETTING: Center for Biomedical Engineering and the Department of Ophthalmology, University of Texas Medical Branch, Galveston, Texas, USA. METHODS: A laser confocal Raman spectroscopy system (Conforam) was used for the noninvasive assessment of Raman spectra in the lower and the higher spectral regions (299.1 to 1833.7 cm-1 and 2633.8 to 3819.6 cm-1, respectively) of 4 IOL materials: silicone, poly(methyl methacrylate) (PMMA), acrylic, and hydrogel. RESULTS: Each lens material showed a distinctive spectrum in both the higher and the lower spectral regions. Most materials had unique peaks and a distinct profile using 1 mW of laser power and a 1 second exposure time. All materials still had a unique spectrum in both the higher and the lower region that allowed 1 material to be distinguished from the others. CONCLUSIONS: A Conforam differentiated silicone, PMMA, acrylic, and hydrogel lenses in vitro. Raman spectroscopy using the Conforam may provide a fast, safe, and reliable noninvasive method to gain information about the material of an implanted IOL and the stability of lens materials and their coatings.

Noninvasive Raman spectroscopic identification of intraocular lens material in the living human eye.

PURPOSE: To develop a safe noninvasive technique for identifying the material of intraocular lenses (IOLs) implanted in patients. SETTING: Center for Biomedical Engineering and the Department of Ophthalmology and Visual Sciences, University of Texas Medical Branch, Galveston, Texas, USA. METHODS: Raman spectroscopy was used to noninvasively identify the type of IOL implanted after previous cataract surgery in 9 eyes of 6 patients who were legally blind as a result of eye disease. Three IOLs were characterized: poly(methyl methacrylate) (PMMA) (n = 5), acrylic (n = 3), and silicone (n = 1). Confocal Raman spectroscopy was used with a laser power of 95 microW and exposure time of 1 second. RESULTS: Distinct spectral peaks associated with each type of IOL were obtained. These included spectra peaks at 2840 cm(-1), 2946 cm(-1), and 3000 cm(-1) for PMMA; 2917 cm(-1), 2939 cm(-1), and 3055 cm(-1) for acrylic; and 2900 cm(-1), 2961 cm(-1), and 3048 cm(-1) for silicone. The procedure was well accepted by patients, and there were no complications. CONCLUSIONS: The specific Raman spectra of the IOLs allowed for noninvasive determination of IOL material with the use of a safe light dose and an exposure time of 1 second.

Determinants of patient satisfaction after cataract surgery in 3 settings.

PURPOSE: To analyze the determinants of satisfaction and postoperative visual function after cataract surgery in 3 settings in The Netherlands. SETTING: University Hospital Maastricht (outpatient care), Atrium Medical Center Heerlen (inpatient care), and Medical Center Maastricht Annadal (outpatient care), Maastricht, The Netherlands. METHODS: This cross-sectional study consisted of 150 patients of 50 years and older who had first-eye phacoemulsification with intraocular lens implantation. Data were collected by a written questionnaire. The following parameters were measured: medical outcome, postoperative function, patient satisfaction with medical outcome and hospital care, and overall patient satisfaction. RESULTS: In general, patients were very satisfied (mean score 8.43 on a 10-point scale ranging from 1 = very bad to 10 = excellent). The 3 centers did not differ regarding the patient satisfaction (P =.092). However, postoperative visual function (P =.012), counseling (P =.010), and waiting time (P <.001) were different among the settings. Patient satisfaction with hospital care had a stronger correlation with overall satisfaction than patient satisfaction with the medical outcome (r = 0.669 versus r = 0.543, respectively). CONCLUSIONS: A causal model of patient satisfaction was tested, indicating that satisfaction was related to the patient's preoperative expectations and the quality of care given during the hospital stay and follow-up at the outpatient clinic. This emphasizes the relevance of patient education (to set realistic expectations) and counseling (need for care) by hospital staff in a cataract surgery setting.

In vivo confocal Raman spectroscopy of the human cornea.

PURPOSE: To investigate the feasibility of a confocal Raman spectroscopic technique for the noninvasive assessment of corneal hydration in vivo in two legally blind subjects. METHODS: A laser beam (632.8 nm; 15 mJ) was maintained on the cornea by using a microscope objective lens (x25 magnification, NA = 0.5, f = 10 mm) both for focusing the incident light as well as collecting the Raman backscattered light, in a 180 degrees backscatter configuration. An optical fiber, acting as the confocal pinhole for elimination of light from out-of-focus places, was coupled to a spectrometer that dispersed the collected light onto a sensitive array detector for rapid spectral data acquisition over a range from 2,890 to 3,590/cm(-1). Raman spectra were recorded from the anterior 100-150 microm of the cornea over a period before and after topical application of a mild dehydrating solution. The ratio between the amplitudes of the signals at 3,400/cm(-1) (OH-vibrational mode of water) and 2,940/cm(-1) (CH-vibrational mode of proteins) was used as a measure for corneal hydration. RESULTS: High signal-to-noise ratio (SNR = 25) Raman spectra were obtained from the human corneas by using 15 mJ of laser light energy. Qualitative changes in the hydration of the anteriormost part of the corneas could be observed as a result of the dehydrating agent. CONCLUSION: With adequate improvements in system safety, confocal Raman spectroscopy could potentially be applied clinically as a noninvasive tool for the assessment of corneal hydration in vivo.

Noninvasive detection of ganciclovir in ocular tissue by Raman spectroscopy: implication for monitoring of drug release.

UNLABELLED: Treatment of various pathological conditions in ophthalmology, such as cytomegalovirus (CMV) retinopathy and endophthalmitis, requires a local drug intervention rather than a systemic approach. Accurate knowledge of intraocular drug concentration can permit the ophthalmologist to maintain drug levels within the therapeutic levels necessary for an optimal prognosis, while preventing or minimizing toxicity associated with drug overdose. PURPOSE: To develop a noninvasive/noncontact method for quantification of the local concentration of ganciclovir in the ocular media. METHODS: An integrated CCD-based Raman spectroscopic system designed specifically for ophthalmic applications was used to noninvasively detect the presence of ganciclovir in the ocular media. Various known concentrations of ganciclovir were injected into the aqueous humor of rabbit eyes in a pilot study, in vivo. Raman spectra were then acquired by focusing an argon laser beam within the anterior chamber of the eye. The specific Raman signature of ganciclovir was assessed at several concentrations. RESULTS: Spectral features unique to ganciclovir were identified and distinguished from those of ocular tissue. The amplitudes of the spectral peaks corresponding to ganciclovir exhibited a linear dependence on the local concentration of the drug in the anterior chamber of the eye. CONCLUSION: Raman spectroscopy may offer an effective tool for the noninvasive assessment of the local concentration of ganciclovir in the ocular media. This technique offers the potential to determine both the amount and the rate of the drug release from implants designed to deliver antiviral drugs locally within the eye. The availability of such data could enable the ophthalmologist to improve treatment efficacy by avoiding premature or late surgical replacement of the implants.

Non-invasive assessment of ocular pharmacokinetics using Confocal Raman Spectroscopy.

A Laser Scanning Confocal Raman Spectroscopy (LSCRS) system was applied for the non-invasive quantification of the transport of a drug through the rabbit cornea in vivo. Employing LSCRS, the changes in the amplitude of a drug-specific Raman signal were assessed over time in the tearfilm and corneal epithelium of the living rabbit eye (n = 6), after topical application of 25 microL Trusopt 2%. This allowed for quantification of pharmacokinetic variables. The effect of the drug on corneal hydration was also monitored. LSCRS demonstrated adequate sensitivity and reproducibility, for continuous real-time monitoring of the Trusopt concentration. Each concentration-time curve had a bi-phasic trend; the rapid initial phase (t<8 min.) corresponds to the nonproductive losses of Trusopt from the tears (k10 = 0.24+/-0.04 min(-1), and the slower later phase (t>20 min.) is the result of transfer of the drug from the corneal epithelium to the stroma (k23 = 0.0047+/-0.0004 min(-1). Drug absorption into the corneal epithelium occurred at a rate of k12 = 0.034+/-0.006 min(-1). Trusopt caused an acute dehydrating effect, with a maximum decrease in corneal hydration of approximately 15% at approximately 60 min. following application of the drug. LSCRS has the specificity, sensitivity, reproducibility and spatial resolution for employment as a potentially valuable tool for the study of ocular pharmacokinetics.

Alagille syndrome in a family with duplication 20p11.

Alagille syndrome (arteriohepatic dysplasia, AHD) is a well defined genetic disorder with five major features: distinctive facies, cardiovascular anomalies, paucity of interlobular bile ducts (PILBD), ocular anomalies and minor skeletal malformations. Repeatedly, structural anomalies of 20p, in most cases a deletion, have been described in patients with Alagille syndrome. We report a three generation family with AHD presenting with typical facial dysmorphology, cardiac and ocular lesions but without clinical signs of liver manifestation. Two infants died from a complex cardiovascular malformation consisting of pulmonary valve atresia, hypoplasia of the pulmonary arteries and VSD. The diagnosis was not appreciated until ocular anomalies were found in the father and the distinctive facies became apparent in the daughter. Chromosome region 20p could not be interpreted precisely by high resolution banding. Using in situ hybridization a duplication 20p11.21-p11.23 was found segregating with the disorder in the family.

[Laser treatment of diabetic macular edema]. / Le traitement au laser de l'oedème maculaire diabétique.

Diabetic macular oedema may be treated by focal or by grid photocoagulations. Indications are discussed.

[Consensus on diagnosis, screening and treatment of diabetic retinopathy]. / Consensus over diagnose, screening en behandeling van diabetische retinopathie.

The management and timing of the treatment of diabetic retinopathy has changed in recent years. Screening for diabetic retinopathy should preferably be performed by ophthalmologists. However, in concert with the local ophthalmologist general physicians with knowledge and experience of eye investigations can play a certain part in the screening for diabetic retinopathy. Good communication between general physician and ophthalmologist is of special interest in detecting the risk factors; systemic hypertension, poor metabolic control, pregnancy, proteinuria and rapid metabolic control of previously high blood glucose levels. For the time being fundus photography as a screening method can only be used on a limited scale and under scientific conditions. No consensus could be reached concerning the pre-treatment use of fluorescein angiography.