The confocal scanning laser ophthalmoscopy ancillary study to the ocular hypertension treatment study: study design and baseline factors

PURPOSE: To describe the study design of the Confocal Scanning Laser Ophthalmoscopy (CSLO) Ancillary Study to the Ocular Hypertension Treatment Study (OHTS) and to examine the associations between optic disk topography, and baseline demographic, clinical, and ocular factors at study entry. DESIGN: A randomized clinical trial. METHODS: Participants in this ancillary study were recruited from seven of the 22 OHTS clinical centers. Each participant completed imaging annually using a CSLO, the Heidelberg Retina Tomograph (HRT). Associations between HRT topographic optic disk measurements and intraocular pressure (IOP), baseline photographic estimates of horizontal and vertical cup-to-disk diameter ratios by the OHTS Optic Disk Reading Center, baseline visual field indices, and demographic and clinical factors were assessed using linear mixed effects models. RESULTS: Four hundred thirty-nine participants had good quality images and were included in this baseline analysis. No associations between HRT topographic optic disk measurements and diabetes, systemic hypertension, cardiovascular disease, IOP, or visual function were found. The HRT topographic optic disk measurements were associated with baseline stereophotographic estimates of horizontal and vertical cup-to-disk diameter ratios. The strongest associations were found between stereophotographic assessment of horizontal and vertical cup-to-disk diameter ratios, and HRT cup-to-disk area ratio (r =.85 and.84, respectively), rim-to-disk area ratio (r = -.85 and -.84, respectively), mean cup depth (r =.84 and.83, respectively), and cup area (r =.83 and.80, respectively). After adjusting for optic disk area, all HRT topographic optic disk measurements remained associated with stereophotographic assessment of horizontal and vertical cup-to-disk diameter ratios. CONCLUSIONS: The CSLO ancillary study to the OHTS is the first multicenter clinical trial to use CSLO imaging to monitor changes in the optic disk. At study entry, HRT topographic measurements corresponded well with both horizontal and vertical stereophotographic-based estimates of cup-to-disk diameter ratio in ocular hypertensive participants.     

The construction of a model eye for investigation of laser-tissue interactions in scanning laser ophthalmoscopy.

PURPOSE: To develop a model eye to study laser-tissue interactions during retinal imaging with scanning ophthalmoscopy. METHODS: A model eye was designed to match the optical properties of the human eye based on the Bennett and Rabbetts schematic eye. RESULTS: Alterations in axial length resulted in changes in refractive error similar to those in the human eye (3.70 D for 1 mm in axial length). Perfusion-fixed retinal tissue could be successfully imaged using the Heidelberg Retina Tomograph and Optical Coherence Tomograph to provide images that are similar in quality to those obtained. CONCLUSIONS: The model eye should be a valuable tool for investigating laser-tissue interactions during scanning laser ophthalmoscopy and the derivation of digital retinal and tomographic images. This model should also enable a determination of the accuracy with which digital imaging techniques, such as the optical coherence tomograph and Heidelberg Retina Tomograph, measure retinal structure.     

A pilot study to detect glaucoma with confocal scanning laser ophthalmoscopy compared with nonmydriatic stereoscopic photography in a community health screening

PURPOSE: To assess the efficacy and practical usefulness of the Heidelberg Retina Tomograph II (HRT II) compared with nonmydriatic stereoscopic photography in a public glaucoma screening. METHODS: We examined 1173 local residents, aged 40 years or older, who visited a community health screening in Komatsu City. Initial glaucoma screening consisted of noncontact pneumotonometry, nonmydriatic stereoscopic fundus photography, and HRT II. When glaucoma was suspected, the subjects were referred for a definitive examination, in which slit-lamp biomicroscopic examination, Goldmann applanation tonometry, Humphrey 30-2 test, gonioscopy, and optic nerve head evaluation were performed. RESULTS: A total of 97.2% (2279/2345) of the nonmydriatic stereoscopic optic disc photographs could be interpreted and 93.4% (2189/2345) were good images. HRT II measurements were successful in 99.0% (2322/2345) of eyes, and acceptable images were obtained in 91.9% (2154/2345) of eyes. On the basis of clinical diagnoses, 94 eyes of 60 participants were diagnosed with glaucoma. The sensitivity of nonmydriatic stereoscopic photographs for personal-level analysis and eye-level analysis was 95.8% and 95.5%, respectively. Using Moorfield's regression analysis, HRT sensitivity and specificity were 72.3% to 91.5% and 84.0% to 93.1%, respectively, for personal-level analysis, and 60.3% to 72.6% and 89.7% to 95.6%, respectively, for eye-level analysis. CONCLUSION: Although HRT II did not detect glaucoma as well as optic nerve stereophotographs in this Japanese population, it may play a role in community health screening.     

Screening for glaucoma with Moorfields regression analysis and glaucoma probability score in confocal scanning laser ophthalmoscopy

Objective

To compare the validity of Moorfields regression analysis (MRA) and glaucoma probability score (GPS) of the confocal scanning laser ophthalmoscopy (Heidelberg retina tomograph 3; HRT3) in detecting glaucomatous optic nerve damage in a screening population.

Design

Population-based, cross-sectional study.

Participants

Subjects at high risk for development of open-angle glaucoma (OAG).

Methods

All subjects underwent confocal scanning ophthalmoscopy (Heidelberg retina tomograph; HRTII) testing, visual fields testing with frequency-doubling technology perimetry (FDT), and a standard ophthalmologic examination. All HRTII images were reprocessed with HRT3. Based on an ophthalmologic examination and FDT results, eyes were classified into 4 categories: normal, possible glaucoma, probable glaucoma, and definitive glaucoma. Main outcome measures included sensitivity and specificity of HRTII/MRA, HRT3/MRA, HRT3/GPS, and combination HRT3/MRA/GPS.

Results

The left eyes of 221 of 291 subjects were included; 4 (1.8%) eyes were classified as definitively having glaucoma. Depending on the reference standard diagnosis as well as on the borderline test-positive definition of the HRTII-3, sensitivity and specificity varied between 36.4% and 100%. For HRTII/MRA, 88.2% to 96.5%, 54.5% to 100%, and 74.5% to 93.6%; for HRT3/MRA, 61.9% to 100% and 64.3% to 85.2%; for HRT3/GPS, 85.7% to 100%; and for combination HRT3/MRA/GPS, 73.4% to 78.2%.

Conclusions

In this pilot study, the MRA of the HRT3 appears to be more sensitive but less specific than the MRA in the HRTII version. The GPS, although somewhat less specific than MRA (and some discs are nonclassifiable by this technique), had greater sensitivity and as a screening method may have the additional advantage of being contour-line independent.     

The influence of axial length on confocal scanning laser ophthalmoscopy and spectral-domain optical coherence tomography size measurements: a pilot study

Purpose

To investigate the influence of axial length on SD-OCT and cSLO size measurements from the Heidelberg Spectralis.

Methods

In this pilot study, eight emmetropic pseudophakic eyes with subretinal visual implant were selected. The axial length was measured in three short (<22.5 mm), three medium (22.51–25.50 mm) and two long (>25.52 mm) eyes. The known size of subretinal implant sensor field (2800?×?2800 μm) was measured on 15 images per eye with cSLO and SD-OCT.

Results

The mean axial length was 20.8?±?0.8 mm in short eyes, 23.3?±?0.4 mm in medium eyes, and 26.3?±?0.5 mm in long eyes respectively. We found in short eyes, in medium eyes and in long eyes a mean value of sensor field size measurements from cSLO of 3327?±?9 μm, 2800?±?9 μm and 2589?±?12 μm and from SD-OCT of 3328?±?9 μm, 2800?±?12 μm and 2585?±?19 μm respectively. The size measurements decreased in SD-OCT and cSLO measurements with longer axial lengths significantly (p?<?0.0001).

Conclusion

The present findings demonstrate accuracy of the scaling in cSLO and SD-OCT measurements of the Heidelberg Spectralis for emmetropic medium eyes. The size measurements from SD-OCT to those from cSLO were approximately equal. Caution is recommended when comparing the measured values of short and long eyes with the normative database of the instrument. Further studies with larger sample sizes are needed to confirm findings.     

Detection of drusen in the fellow eye of Japanese patients with age-related macular degeneration using scanning laser ophthalmoscopy

OBJECTIVE: To study the prevalence of drusen in the fellow eye of Japanese patients with age-related macular degeneration (AMD). DESIGN: Retrospective, cross-sectional study. PARTICIPANTS: Seventeen eyes of 17 Japanese patients with unilateral AMD. MAIN OUTCOME MEASURES: To compare the frequency of drusen based on photography and scanning laser ophthalmoscopy with confocal and ring apertures and a diode laser (780 nm). RESULTS: Using the scanning laser ophthalmoscope (SLO) with a ring aperture, drusen were detected clearly as in topographic imaging. In the fellow eyes of the study patients with AMD, photography showed drusen in 10 cases (58.8%); however, SLO imaging detected drusen in 15 cases (88.2%). The number of drusen detected using SLO imaging was significantly greater than when using photography (P < 0.05). CONCLUSIONS: Scanning laser ophthalmoscope imaging is superior to photography for detecting drusen in the fellow eyes of Japanese patients with unilateral AMD. The prevalence of drusen in the fellow eye of Japanese patients with AMD is much higher than previously speculated.     

Measurement of eye rotations in three dimensions and the retinal stimulus projection using scanning laser ophthalmoscopy

A transformation algorithm is introduced to specify eye rotations in three dimensions from two-dimensional translations of ocular fundus landmarks dynamically monitored by means of the novel Scanning Laser Ophthalmoscope (SLO). The rotation parameters are expressed as Y-X-Z Euler angles and in terms of the rotation axis and one rotation angle. Additionally, the angular distance of the retinal stimulus projection can be evaluated relative to the fovea. By simultaneously operating as eye movement measurement device, fundus camera, and visual target projector, the SLO opens a variety of new applications for the combined analysis of eye movements and the underlying 'retinal events' in vision and oculomotor research.     

Mizuo phenomenon observed by scanning laser ophthalmoscopy in a patient with Oguchi disease

PURPOSE: To elucidate the origin of the abnormal fundus reflex in Oguchi disease. METHODS: The ocular fundus of a 63-year-old woman who showed a homozygous arrestin 1147delA mutation was observed by scanning laser ophthalmoscopy with the use of an argon blue laser (wavelength, 488 nm), a helium-neon laser (633 nm), and an infrared laser (780 nm). RESULTS: Diffuse, fine, white particles, which do not exist in normal subjects, were clearly demonstrated only with the helium-neon laser. After 4-hour dark adaptation, the abnormal particles disappeared, but then they reappeared gradually during 30 minutes of light adaptation, in accordance with the golden metallic reflex. CONCLUSION: The white particles found by helium-neon laser could be the origin of the abnormal fundus reflex in Oguchi disease.     

The noninvasive retro-mode imaging of confocal scanning laser ophthalmoscopy in myopic maculopathy: a prospective observational study

Purpose

To investigate the morphological features of myopic maculopathy with a new and noninvasive retro-mode imaging (RMI) technique using a confocal scanning laser ophthalmoscope.

Methods

A total of 42 patients (69 eyes) with myopic maculopathy were included. RMI combined with fundus photography, fundus fluorescein angiography, and optical coherence tomography together were used to observe and evaluate the morphological features of disease.

Results

Four in 4 eyes (100%) with macular retinoschisis were found with a characteristic pattern by RMI (firework pattern centrally with surrounding fingerprint pattern). Twenty-four in 24 eyes (100%) with pigment proliferation were found by RMI as dark plain patches, and 23 in 24 eyes with hemorrhage (95.8%) were found by RMI as gray bump. Atrophy of different degrees (12 in 14 eyes, 85.7%) was found by RMI as an area of pseudo-3D choroidal vessels or a fuzzy shadow but both without a clear boundary. Choroidal neovascularization (12 in 16 eyes, 75%) was identified laboriously by RMI as a vague raised region. Lacquer cracks were difficult to figure out in RMI.

Conclusions

Retinoschisis, pigment proliferation, hemorrhage, and atrophy secondary to myopic maculopathy have characteristic morphologic features in RMI; however, choroidal neovascularization and lacquer crack are not easily distinguishable in RMI.     

Ocular fundus images by scanning laser ophthalmoscopy in a patient with enhanced S-cone syndrome

PURPOSE: To present ocular fundus images in a patient with enhanced S-cone syndrome by scanning laser ophthalmoscopy. A 34-year-old Japanese woman whose parents were consanguineous showed mismatched electroretinographic responses to photopically balanced single-flash stimuli, with a larger signal to blue light than to red light. The central macula lacked a foveal reflex, and the surface was dull. Yellowish flecks and retinal pigment epithelium atrophy were evident in a ring at and around the vascular arcades. Faint black pigmentation was deposited in the mid peripheral retina. METHODS: The ocular fundus of the patient was observed by scanning laser ophthalmoscopy with the use of an argon blue laser (wavelength, 488 nm), a helium-neon laser (633 nm), and an infrared laser (780 nm). RESULTS: The argon blue laser showed numerous black spots of pigment, which were observed as faint pigmentation by conventional ophthalmoscopy. The spots were more enhanced with the argon blue laser than with the helium-neon laser. The white spots, which corresponded to the yellowish flecks in a ring at and around the vascular arcades, were more enhanced with the helium-neon laser than with the argon blue or infrared laser. Hypopigmentation of the retinal pigment epithelium was best shown with the infrared laser. CONCLUSION: An abnormality of the retinal structure in enhanced S-cone syndrome may exist in the inner and outer retinal levels, in at least some patients.     

Blue on yellow perimetry with scanning laser ophthalmoscopy in patients with age related macular disease

BACKGROUND/AIM: The loss of short wavelength sensitive (SWS) cone mechanism sensitivity is related to severe vision loss in patients with age related maculopathy (ARM). A case-control study of patients with ARM and age matched controls was performed, using blue on yellow static perimetry. METHODS: A bright yellow background at 594 nm isolated the responses of short wavelength cone mechanisms to 458 nm targets. A scanning laser ophthalmoscope produced stimuli and provided real time, simultaneous fundus illumination. The macula was probed with 16 Goldmann IV targets, 1-10 degrees from fixation, using a staircase method. RESULTS: 24 patients with non-exudative ARM were matched to 24 subjects with normal fundus appearance. SWS cone pathway sensitivity for macular targets was significantly reduced in the patients with ARM compared to normals--15.45 (SD 4.56) dB v 17.22 (0.28) dB, respectively (p<0.0005). There was not only a diffuse loss of sensitivity in ARM patients, but also a localised loss of sensitivity over drusen (p<0.025). Neither the mean age, 69 (8) years, nor the mean visual acuity differed between groups, logMAR 0.09 (0.10) v 0.05 (0.06) for ARM patients v normals, respectively. Patients with soft drusen had lower sensitivity than those with hard drusen (p<0.05). CONCLUSION: A loss of SWS cone pathway sensitivity occurred in most patients with early ARM, despite good visual acuity, demonstrating a loss of visual function that cannot be attributed to ageing changes. The loss of sensitivity, despite good visual acuity, included both a diffuse loss and localised losses.     

Agreement and repeatability for standard automated perimetry and confocal scanning laser ophthalmoscopy in the diagnostic innovations in glaucoma study

PURPOSE: To assess agreement between structural and functional testing in classifying eyes as normal or abnormal and their repeatability on two consecutive visits by means of standard automated perimetry (SAP) and confocal scanning laser ophthalmoscopy. DESIGN: Analysis of selected data obtained from a prospective longitudinal observational cohort study, the Diagnostic Innovations in Glaucoma Study. METHODS: One hundred fifty-one participants with a SAP and a Heidelberg Retina Tomograph (HRT) test within a three-month window at two visits within 15 months were included. Eyes were classified by SAP and HRT at each visit. Agreement and repeatability were assessed by kappa statistics. RESULTS: At visit 1, 33 (22%) of 151 eyes had only SAP defects, 11 (7%) eyes had only HRT defects, and 35 (23%) eyes had both SAP and HRT defects. Seventy-two eyes (48%) were classified as normal by both tests. Similar results were obtained for visit 2. The agreement between SAP and HRT in classifying eyes was 70% (kappa = 0.393) at visit one and 68% (kappa = 0.363) at visit 2. Repeatability of classification by SAP alone, HRT alone, and both SAP and HRT between visits 1 and 2 was 84% (kappa = 0.693), 89% (kappa = 0.752), and 90% (kappa = 0.723), respectively. CONCLUSIONS: Agreement between SAP and HRT was only fair at both visits. Repeatability across visits was substantial for SAP alone, HRT alone, and for the combination of SAP and HRT. These results suggest that detection of particular features of glaucomatous damage depends on the technique used. Structural and functional tests appear complementary, and both should be used for early detection of glaucoma.     

Advances in the diagnosis and therapy for diseases of the ocular surface: dry eye and ocular allergies

The 77th meeting of the Association for Research in Vision and Ophthalmology (ARVO) presented the latest developments in clinical research and practice across a range of ophthalmic disciplines. Of particular interest was the current status of research in dry eye and ocular allergy. With these conditions being very common to ophthalmologists, and the fact that they are difficult to differentiate due to the number of overlapping symptoms, there remains a need for more rapid and accurate methods for their diagnosis. Therefore, a number of new tools were presented that have the potential for use in clinical trials and practice to improve the diagnosis and assessment of dry eye and ocular allergy. Some of these tools have been developed based on a greater understanding of the pathophysiology of dry eye and ocular allergy, and the various molecular pathways involved. Indeed, a greater understanding of the molecular mechanisms involved in the pathogenesis of dry eye and ocular allergy has identified potential targets for the treatment of these conditions. Continuing research into new agents can provide ophthalmologists with a number of options that will ultimately benefit the patient.