[Primary stromal cyst of the iris: case report]

Primary stromal cysts of the iris are rare, often asymptomatic, and incidentally found entities. Treatment is usually indicated in cases of enlargement or complications. However, imaging tests are required to determine their cystic nature and make an accurate differential diagnosis with malignant tumors, as well as for long-term follow-up. Ultrasound biomicroscopy is the technique of choice, although in most centers anterior segment optical coherence tomography is a more accessible and available imaging modality. We present a case of primary stromal cyst of the iris with an atypical presentation to illustrate the diagnosis and initial follow-up using anterior segment optical coherence tomography and photographs, and the management of complications. Anterior segment optical coherence tomography may be useful in the initial study and follow-up of anterior non-pigmented lesions where the cyst can be fully seen.

Use of the Visante™ OCT to measure the sagittal depth and scleral shape of keratoconus compared to normal corneae: Pilot study

Purpose

The purpose of this study is to demonstrate and compare the use of optical coherence tomography (OCT) in measuring sagittal depth (SD) and in describing the corneo–scleral junctions with the use of scleral angles, in a population of keratoconics (KC) and of normals (normal).

Methods

Fourteen participants (one eye randomly selected) in the normal group and fourteen eyes of nine participants in the keratoconus group were enrolled in the study. Orbscan II (B&L, Rochester) topography was performed to establish eligibility, steep and flat K readings (axes) and HVID. Measurements of the sagittal depth of the cornea and the scleral angles along a particular chord diameter (their HVID and 15 mm) both flat and steep were taken with the use of the on screen measurement tools from the profile view of the cornea of the Visante™ OCT (Carl Zeiss, Dublin, CA).

Results

Data were taken from 14 eyes (11 Females; 3 Males) in the normal group and 14 eyes (5 females; 9 males) in the KC group where either or both eyes were measured. The study participants had a mean age of 33 ± 7yrs (normal) and 40 ± 14yrs (KC). The groups were matched according to HVID: 11.77 ± 0.41 mm (normal) and 11.75 ± 0.35 mm (KC), (p = 0.880). The steep K readings were 53.74 ± 5.98D for the keratoconus eyes as compared to 43.77 ± 1.35D for the control (p < 0.0001). The sagittal depths (±SD) of the keratoconic cornea were significantly different than the normal corneae at their HVID and at 15 mm in the steep meridian only (3.41 ± 0.88 mm versus 2.42 ± 0.09 mm, p = 0.001 and 3.93 ± 0.25 mm versus 3.70 ± 0.16 mm, p = 0.009, respectively). In addition, when the two groups were compared there was no difference in the scleral angles at the HVID's overall (p = 0.490), but there were differences by location (inferior and temporal, p = 0.003). At the 15 mm chord, there was a significant difference between the groups (p = 0.012) overall, but not by location (p = 0.130).

Conclusions

Measurement of the sagittal depth and the corneal-scleral junction angle in the steepest meridian at either the HVID or at 15 mm are two metrics that significantly differentiate normals from keratoconics.

Preliminary in vivo positional analysis of a posterior chamber phakic intraocular lens by optical coherence tomography and its correlation with clinical outcomes

Purpose

To analyze by spectral-domain optical coherence tomography the anatomical relationship of a specific type of posterior chamber phakic intraocular lens (pIOL) implanted in cases of high to moderate myopia with the adjacent intraocular structures and to correlate it with clinical outcomes.

Methods

Prospective observational case series including 18 eyes with high to moderate myopia (spherical equivalent between −5.88 and −15.75 D) of 9 patients (age range, 29–49 years) undergoing bilateral Phakic Refractive Lens (PRL, Zeiss) implantation. Postoperative visual acuity, refraction, contrast sensitivity (CS), and ocular higher order aberrations (HOA) were evaluated. Furthermore, the in vivo position of the PRL was analyzed by means of spectral domain optical coherence tomography (3D OCT-1000, Topcon). Central (CENV), temporal (TEMV) and nasal vault (NASV) were measured. Correlation of these anatomical parameters with clinical data was also investigated. Mean follow-up was 47 ± 25 months.

Results

A statistically significant visual and refractive improvement (p < 0.01) was found postoperatively. Mean postoperative CENV, NASV, and TEMV were 157.88 ± 69.93 μm, 168.29 ± 65.02 μm, and 188.59 ± 55.99 μm, respectively. Significant difference was found between NASV and TEMV (p = 0.01). No significant correlations were found between ocular aberrometric and anatomical parameters (p ≥ 0.12). CENV, NASV and TEMV correlated significantly with 6-cycles per degree (cpd) photopic CS as well as with 18-cpd low mesopic CS (r ≥ 0.57, p ≤ 0.04). Furthermore, NASV also correlated significantly with preoperative anterior chamber depth (r = −0.65, p = 0.01).

Conclusions

This posterior chamber pIOL shows a trend to nasal position, with potential impact on refractive and visual outcomes, particularly in eyes with deep anterior chambers.

Relationship Between Visual Field Sensitivity and Retinal Nerve Fiber Layer Thickness Measured by Scanning Laser Polarimetry and Optical Coherence Tomography in Normal, Ocular Hypertensive and Glaucomatous Eyes

Purpose

To evaluate the correlation between automated achromatic perimetry (AAP) and the output of two retinal nerve fiber layer (RNFL) analysers: scanning laser polarimetry (GDx-VCC) and optical coherence tomography (OCT).

Methods

Quantitative RNFL measurements with GDx-VCC and Stratus-OCT were obtained in one eye from 52 healthy subjects, 38 ocular hypertensive (OHT) patients and 94 glaucomatous patients. All patients underwent a complete examination, including AAP using the Swedish interactive threshold algorithm (SITA). The relationship between RNFL measurements and SITA visual field global indices were assessed by means of the following methods: analysis of variance, bivariate Pearson's correlation coefficient, multivariate linear regression techniques and nonlinear regression models, and the coefficient of determination (r²) was calculated.

Results

RNFL thickness values were significantly lower in glaucomatous eyes than in healthy and ocular hypertensive eyes for both nerve fiber analysers (P≤0.001), except for the inferior 120° average thickness in GDx-VCC. Linear regression models constructed for GDx-VCC measurements and OCT-derived RNFL thickness with SITA visual field global indices demonstrated that, for the mean deviation, the only predictor in the model was the nerve fiber indicator for GDx-VCC (r²=0.255), and for the pattern standard deviation, the predictors in the model were the nerve fiber indicator for GDx-VCC (r²=0.246) and the maximum thickness in the superior quadrant for Stratus-OCT (r²=0.196). The best curvilinear fit was obtained with the cubic model.

Conclusions

Quantitative measurements of RNFL thickness using either GDx-VCC or OCT correlate moderately with visual field global indices in moderate glaucoma patients. We did not find a correlation between visual field global indices and RNFL thickness in early glaucoma patients. Further study is needed to develop new analytical methods that will increase RNFL analyser's sensitivity in early glaucoma patients.