Purpose: To investigate the variation and symmetry of cone density distribution along the nasal and temporal retina of fellow eyes. Methods: An adaptive optics retinal camera (rtx1; Imagine Eyes) was used to obtain images of the parafoveal cone mosaic in 20 healthy subjects. Cone density was estimated at 250, 420, 760, and 1,300 μm eccentricity from the fovea along the nasal and temporal retina of both eyes in each subject. The coefficient of variation and the intraclass correlation coefficient were used to calculate the variation and absolute agreement of cone density between the same retinal eccentricity locations of fellow eyes, respectively. Results: A considerable variation of cone density between subjects was found at all eccentricities along the nasal and temporal retina (intersubject coefficient of variation ≥ 11%, P < 0.001). The intrasubject variation of cone density was, however, moderate (coefficient of variation ≤ 13% in 95% of the subjects); a high agreement was, on average, found between the cone density estimates at the same eccentricity along the nasal and temporal retina of fellow eyes (intraclass correlation coefficient ≥ 0.86, P < 0.001). Conclusion: Cone density follows a symmetrical distribution between fellow eyes. A systematic distribution of parafoveal cones between fellow eyes may provide an anatomical basis for the involvement of the photoreceptor layer in the first step of binocular spatial sampling.

Corneal tomography is an important tool to identify and follow up eyes with keratoconus. Our study evaluate the repeatability of the automatic measurements provided in keratoconic eyes by a new anterior-segment optical coherence tomographer (AS-OCT) combined with Placido-disk topography (MS-39, CSO) and assess their agreement with the corresponding measurements taken with a rotating Scheimpflug camera combined with Placido-disk topography (Sirius, CSO). Mean simulated keratometry, posterior and total corneal power, total corneal astigmatism, corneal asphericity, thinnest corneal thickness, epithelial thickness, corneal diameter, and aqueous depth were evaluated. Repeatability was assessed using test–retest variability, the coefficient of variation, and the intraclass correlation coefficient; agreement was assessed by the 95% limits of agreement. Good repeatability was achieved for most parameters. Moderate repeatability was found for total corneal astigmatism measurements. The repeatability of mean simulated keratometry and total corneal power measurements worsened with more severe stages of keratoconus with a statistically significant relationship between the individual coefficient of variation and corneal power values. Agreement with the Scheimpflug camera was moderate for aqueous depth and thinnest corneal thickness and poor for most other measured parameters. The good repeatability of automatic measurements suggests the new AS-OCT device to be a viable option in clinical practice of eyes with keratoconus.

To investigate and compare the surface roughness and morphology of posterior stromal lenticules created with a femtosecond laser using various pulse energies to that obtained with a mechanical microkeratome. A 150 kHz femtosecond laser platform (IntraLase iFS; Abbott Medical Optics) was programmed to create an 8.5-mm-diameter posterior stromal lenticule in 12 human corneal tissues. Specimens were dissected using different pulse energies (1.00, 0.75, 0.65, and 0.50) and fixed 2 μm spot separations. Three additional posterior corneal lenticules were prepared using a mechanical microkeratome (Moria Evolution 3; Moria). After the procedure, each corneal tissue was examined by atomic force microscopy (Autoprobe CP; Veeco). Femtosecond laser-treated tissues revealed similar morphological features, however, with significant differences in surface roughness in relation to the energy pulse used for lamellar dissection (P0.05). Atomic force microscopy submicron analysis of femtosecond-dissected donor tissues provided quantitative demonstration of the relation between pulse energy and stromal surface roughness. Surface quality of posterior corneal lenticules, comparable with that provided by mechanical microkeratome, is significantly improved when setting pulse energy for lamellar dissection of 0.50-μJ and 2-μm spot separations.

To assess functional and structural retinal changes in patients with neovascular age-related macular degeneration treated with intravitreal ranibizumab 0.5 mg. Eighteen patients with neovascular age-related macular degeneration have been evaluated in this retrospective 24-week follow-up study. All patients were treated with three injections of ranibizumab 0.5 mg, 1 month apart and retreated according to predefined criteria. At baseline, all patients were subjected to visual acuity measurement, fluorescein angiography, microperimetry, and optical coherence tomography stratus. Visual acuity, microperimetry, and optical coherence tomography evaluations were repeated 28 +/- 2 days after each injection. Mean retinal sensitivity significantly improved from 3.89 +/- 3.0 dB at baseline to 6.61 +/- 3.4 dB at 24 weeks (P = 0.044). Mean visual acuity significantly improved from 48.67 +/- 8.58 to 60.72 +/- 16.09 (P = 0.026); visual acuity improved in 44.4% of patients > or =15 letters (24.5 +/- 8.0 letters), and in 38.9% of patients improved <15 letters (6.14 +/- 3.7 letters); 16.7% of patients lost <15 letters (7.3 +/- 2.1 letters). An improvement of fixation stability from baseline was observed in 33.3% of patients. Central macular thickness significantly decreased from 310.5 +/- 85.7 microm to 217.3 +/- 46.8 microm at 24 weeks (P < 0.001). Although visual acuity and retinal thickness changes seemed to be almost maximum at 4 weeks after intravitreal ranibizumab 0.5 mg, retinal sensitivity as measured by microperimetry showed a trend of progressive improvement till 24 weeks suggesting that microperimetry may give additional information about macular function not given by visual acuity alone.