Stefano Da Pozzo

GDx-VCC performance in discriminating normal from glaucomatous eyes with early visual field loss

BackgroundTo evaluate the ability of scanning laser polarimetry with variable corneal compensation (GDx-VCC) in separating healthy from glaucomatous patients with early visual field (VF) loss.MethodsSixty-two healthy and 48 glaucomatous age-matched patients with early glaucoma [mean deviation (MD): −1.74dB ±1.69] underwent complete ophthalmological evaluation, automated achromatic perimetry (AAP) and retinal nerve fiber layer (RNFL) measurement with GDx-VCC. One randomly selected eye from each subject was considered. Glaucomatous VF defects had either Glaucoma Hemifield Test (GHT) outside normal limits or pattern standard deviation (PSD) outside 95% confidence limits. Mean (±SD) MD, PSD and GDx-VCC parameters in the two groups were compared by t-test. For each GDx-VCC parameter, area under receiver operating characteristics (AUROC) curve and sensitivity at predetermined specificity ≥80% and ≥95% were calculated. Moreover, the parameter with largest AUROC was evaluated by likelihood ratios (LRs).ResultsMean values for MD, PSD and ten of 14 GDx-VCC parameters were significantly different between the two groups (P<0.001). The three parameters with largest AUROCs were the nerve fiber indicator (NFI) (0.870), superior average (0.817) and normalized superior area (0.816) (P=0.08 for differences between AUROCs). NFI displayed sensitivity values of 80.2% and 60.4% for specificity ≥80% and ≥95%, respectively. At NFI cutoff value of 30, positive LR was 34.9 (95% CI: 4.9–247.6) and negative LR was 0.45 (95% CI: 0.32–0.61). Interval LRs showed large effect on post-test probability for NFI values ≤18 or ≥31.ConclusionsIn our sample of eyes with early VF loss, GDx-VCC showed moderate-to-good discriminating ability. Among the best performing parameters, NFI had the largest AUROC, but several glaucomatous eyes (21, 43.8%) had NFI <30. This suggests that algorithm for NFI calculation requires some refinement when eyes with early VF loss are evaluated.

Occult Choroidal Neovascularization in Adult-Onset Foveomacular Vitelliform Dystrophy

Aims: To report 6 cases in which indocyanine green angiography (ICGA) failed to convert occult choroidal neovascularization (CNV) into well-defined CNV in adult-onset foveomacular vitelliform dystrophy (AOFVD). Methods: Patients with AOFVD observed from 1993 to 1999 were prospectively followed up. Whenever the development of CNV was suspected, ICGA was performed to detect the precise location and extension of CNV by means of the IMAGEnet System. Results: Six out of 51 patients (11.7%) developed CNV during the follow-up. The CNV was of the occult type, with an associated detachment of the pigment epithelium in 1 eye. On ICGA, a large hyperfluorescent lesion appeared after about 10 min, irregularly increasing with time, without a clear visualization of site and extension of CNV. Conclusions: In AOFVD, ICGA may fail to convert occult CNV into well-defined CNV, which is amenable to laser treatment, since hyperfluorescence caused by the probably vitelliform material binding to the ICG molecule and the CNV-induced hyperfluorescence cannot be angiographically distinguished from each other.

Scanning laser polarimetry with variable corneal compensation and detection of glaucomatous optic neuropathy

BackgroundThe aim of this study was to evaluate the ability of scanning laser polarimetry (SLP) parameters provided by commercially available GDx with variable corneal compensator (VCC) to discriminate between healthy and glaucomatous eyes.MethodsSixty-five healthy and 59 glaucomatous age-matched patients underwent a complete ophthalmological evaluation, an achromatic automated perimetry (AAP), and SLP with GDx-VCC. One randomly selected eye from each subject was considered. All glaucomatous eyes had reproducible visual field defects. Mean values (± SD) of all SLP-VCC parameters measured in the two groups were compared. Area under receiver operating characteristics (AUROC) curve and sensitivities at predetermined specificities of ≥80% and ≥95% for each single parameter were calculated. Moreover, the nerve fiber indicator (NFI) diagnostic accuracy was evaluated calculating positive, negative, and interval likelihood ratios (LRs) at different cutoff values.ResultsAll SLP parameters were significantly different between the two groups (p<0.001). The NFI showed the best AUROC curve (0.938, SE 0.02) whereas temporal, superior, nasal, inferior, temporal (TSNIT) average was second best (0.897, SE 0.03), and normalized superior area was third (0.879, SE 0.04). At fixed specificity ≥95%, sensitivities ranged from 22% to 79.7% whereas for values ≥80%, sensitivities were in the 44.1–89.8% range. At a cutoff NFI value of 30, positive LR was 17.6 (95% CI: 5.8–53.6) and negative LR was 0.19 (95% CI: 0.11–0.33). Interval LRs for NFI showed that values ≤20 or >40 were associated with large effects on posttest probability.ConclusionsSLP-VCC allows good discrimination between healthy and glaucomatous eyes. New software-provided parameters NFI, TSNIT average, and normalized superior and inferior areas appear to be reliable in the evaluation of glaucomatous disease. In particular, after evaluation on interval LRs, the NFI showed a high diagnostic accuracy for values ≤20 or >40.

IRIS ARTERIOVENOUS COMMUNICATION : CLINICAL AND ANGIOGRAPHIC FEATURES

Background: Iris arteriovenous communication (IAVC) represents a quite rare congenital anomaly, consisting of abnormal vascular connection bypassing the iris capillary bed. The aim of the present study is to describe clinical and angiographic pattern of IAVC on iris fluorescein angiography (IFA) and on indocyanine green videoangiography (IICGV). Methods: During a mean follow-up period of 33.5 months, eight patients affected by IAVC underwent at least three ophthalmological examinations completed by IFA and IICGV. Results: IFA allows the detection of IAVC vascular structures, evidencing afferent and efferent branches, which show a rapid filling, without any evidence of leakage or iris hypoperfusion. IICGV shows more precisely the entire vascular pattern of IAVC, revealing also the presence of iris hypoperfusion in the sector in which the IAVC lay. One patient underwent cataract surgery; three months later, two neovascular tufts appeared in the hypoperfused area related to IAVC. In all other patients, periodical examinations did not reveal any clinical or angiographic changes. Conclusion: In IAVC, the clinical picture appears stable throughout the follow-up; both angiographic techniques seem able to precisely delineate the vascular pattern. Nevertheless, IICGV is superior in showing iris hypoperfusion surrounding the vascular abnormality. Particular care must be drawn to patients affected by IAVC who need cataract surgery.

Branch retinal vein occlusion and macroaneurysms

Background: Macroaneurysms can represent common consequences of branch retinal vein occlusion(BRVO). The aim of the present study is to evaluate the clinical and angiographic aspects of 31 cases of branch retinal vein occlusions (BRVO) in which retinal macroaneurysms developed, in an attempt to analyze their pathogenic features. Methods: One hundred and sixty-one consecutive patients affected by BRVO were considered. Each patient underwent an ophthalmological examination including fluorescein angiography, at an average interval of two months (range: 1–4 months) from the onset of the disease, with a mean follow-up of 43months (range: 32–56 months). The macroaneurysms were subdivided according to size into small (from 100 to149 microns), medium (from 150 to 249 microns), and large (greater than 250 microns), and according to origin into arterial, venous, capillary and collateral-associated. Results: Thirty-one patients (19.3%) developed retinal macroaneurysms. The total number of detected macroaneurysms was 51; ten (19.6%) were large, 21(41.2%) were of medium-size and 20 (39.2%) were small in dimension. Three lesions were of arterial origin, 22 were capillary and 26 were from collateral vessels. In27 patients (87.1%) the lesions were located outside the macular region, and in 4 patients (12.9%) in the macular region. Patients with retinal macroaneurysms did not show a different prevalence of capillary non-perfusion when compared with others. With regard to the number of retinal venous collaterals patients with macroaneurysms developed fewer than other patients, and the difference was statistically significant (p < 0.001). Conclusion: The insufficient number of retinal venous collaterals can be considered the most contributory factor in the development of macroaneurysms secondary to BRVO.

Retinal nerve fibre layer of perimetrically unaffected eyes of glaucoma patients: an optical coherence tomography study

Purpose:  The aim of this study is to evaluate whether optical coherence tomography (StratusOCT) may detect early changes in perimetrically unaffected (PU) fellow eyes of glaucomatous patients by assessing retinal nerve fibre layer (RNFL) thickness parameters.

A pilot study of ICG-guided laser photocoagulation for occult choroidal neovascularization presenting as a focal spot in age-related macular degeneration.

Purpose: To evaluate the effect of indocyanine greenangiography (ICG)-guided laser photocoagulation in eyes withage-related macular degeneration (AMD) and occult choroidalneovascularization (O-CNV), appearing as a well-defined focalspot on ICG. Methods: Eyes with extrafoveal or juxtafovealfocal spot on ICG, either without PED (Group A) or with PED(Group B) at baseline, were selected. The hyperfluorescentarea was photocoagulated by krypton red laser within 24 hoursfrom diagnosis on ICG guide. At 1, 3, 6, 9 and 12 months fromtreatment, all eyes underwent clinical examination, FA and ICG.Parameters as best corrected visual acuity (BCVA), CNV closureand recurrence onset were analyzed. Results: 53 eyes wereenrolled in Group A and 33 in Group B. After 1 year from treatment,a stabilized (±1 Snellen line) or improved (2 or more Snellenlines) visual acuity was measured in 37 eyes (43%), 32 inGroup A and 5 in Group B. After 1 year, a complete resolution ofexudative signs was achieved with one or more laser sessions in41 eyes (48%), 34 in Group A and 7 in Group B. After 1 year, 50eyes (58%) had one or more episodes of recurrent CNV, appearingin 51% of eyes of Group A and in 70% of eyes of Group B. Mostof the recurrences (86%) occurred during the first trimesterafter photocoagulation. Conclusions: ICG-guided laserphotocoagulation for O-CNV appearing as a focal spot producedencouraging anatomical and functional outcome in eyes withoutPED at presentation. When focal CNV is associated with a PED,our treatment technique produced disappointing results.

Scanning laser polarimetry of nerve fiber layer thickness in normal eyes after cataract phacoemulsification and foldable intraocular lens implantation.

Purpose: To assess the effect of cataract phacoemulsification and intraocular lens (IOL) implantation on retinal nerve fiber layer (RNFL) thickness using scanning laser polarimetry (SLP). Setting: Eye Clinic, Trieste University, Italy. Methods: Forty‐eight eyes were evaluated prospectively the day before and 30 days after cataract phacoemulsification and foldable IOL implantation. In each eye, lens opacity grading according to the Lens Opacities Classification System III (LOCS III), and axial length (AL) measurements were performed. Retinal nerve fiber layer thickness was quantified at baseline by means of SLP and anterior segment birefringence compensation was evaluated acquiring macular retardation map (MRM). Acrylic and silicone IOLs were implanted randomly. After surgery, RNFL thickness was reevaluated, and MRM was reacquired. Macular retardation map pattern variations regarding baseline profile were classified into 3 groups: no variation, bow‐tie profile enhancement, or attenuation. Distribution of IOL power, AL, and cataract type in the 3 groups was assessed, as were presurgery and postsurgery SLP parameters with mean values (±SD) compared by paired t test. Results: Twenty‐two eyes (Group 1, 45.8%) showed no MRM variation, 14 (Group 2, 29.2%) an enhancement, and 12 (Group 3, 25%) an attenuation. In Group 1, no significant RNFL thickness variation occurred. In Group 2, variation 10% to 15% was measured, whereas thickening a 8% to 15% thinning appeared in Group 3. Variations occurred irrespective of IOL material, AL, or cataract type. Conclusions: Cataract surgery with IOL implantation was associated with an MRM profile change and RNFL thickness variations in 54.2% of eyes. Variations are probably related to opacified lens removal. A new baseline SLP reading is mandatory after cataract surgery.