The effect of cone opsin mutations on retinal structure and the integrity of the photoreceptor mosaic.

PURPOSE: To evaluate retinal structure and photoreceptor mosaic integrity in subjects with OPN1LW and OPN1MW mutations. METHODS: Eleven subjects were recruited, eight of whom have been previously described. Cone and rod density was measured using images of the photoreceptor mosaic obtained from an adaptive optics scanning light ophthalmoscope (AOSLO). Total retinal thickness, inner retinal thickness, and outer nuclear layer plus Henle fiber layer (ONL+HFL) thickness were measured using cross-sectional spectral-domain optical coherence tomography (SD-OCT) images. Molecular genetic analyses were performed to characterize the OPN1LW/OPN1MW gene array. RESULTS: While disruptions in retinal lamination and cone mosaic structure were observed in all subjects, genotype-specific differences were also observed. For example, subjects with "L/M interchange" mutations resulting from intermixing of ancestral OPN1LW and OPN1MW genes had significant residual cone structure in the parafovea (∼25% of normal), despite widespread retinal disruption that included a large foveal lesion and thinning of the parafoveal inner retina. These subjects also reported a later-onset, progressive loss of visual function. In contrast, subjects with the C203R missense mutation presented with congenital blue cone monochromacy, with retinal lamination defects being restricted to the ONL+HFL and the degree of residual cone structure (8% of normal) being consistent with that expected for the S-cone submosaic. CONCLUSIONS: The photoreceptor phenotype associated with OPN1LW and OPN1MW mutations is highly variable. These findings have implications for the potential restoration of visual function in subjects with opsin mutations. Our study highlights the importance of high-resolution phenotyping to characterize cellular structure in inherited retinal disease; such information will be critical for selecting patients most likely to respond to therapeutic intervention and for establishing a baseline for evaluating treatment efficacy.

Topographical Choroidal Thickness Change Following PDT for CSC: An OCT Case Report.

Purpose. To describe topographical changes in choroidal thickness as measured by optical coherence tomography following photodynamic therapy (PDT) for central serous chorioretinopathy (CSC). Methods. Case report. Results. By 1 month following PDT, mean (SD) choroidal thickness decreased from 562 microns (24) to 424 microns (27) (P < 0.01) at 3 mm temporal to fovea, 483 microns (9) to 341 microns (21) (P < 0.01) at 1.5 mm temporal to fovea, 576 microns (52) to 370 microns (81) (P < 0.01) under the fovea, 442 microns (30) to 331 microns (54) (P < 0.04) at 1.5 mm nasal to fovea, and 274 microns (39) to 171 microns (17) (P < 0.01) at 3 mm nasal to fovea. The Location of greatest choroidal thickness (648 microns) prior to treatment was at point of leakage on fluorescein angiogram (FA). This region decreased to 504 microns following treatment. Conclusion. A decrease in choroidal thickness can be seen following PDT for CSC as far as 3 mm temporal and 3 mm nasal to fovea. The Location of greatest choroidal thickness may be at point of leakage on FA.

Ultra-thin donor tissue preparation for endothelial keratoplasty with a double-pass microkeratome.

PURPOSE: To quantify and describe practically a novel technique for donor tissue preparation in Descemet stripping endothelial keratoplasty to approach the superior visual outcomes of Descemet membrane endothelial keratoplasty. DESIGN: Experimental laboratory investigation. SETTING: Institutional. STUDY POPULATION: Eleven human donor corneas. INTERVENTION: Double-pass of microkeratome over donor corneas-first with a thicker cutting depth and subsequently with a thinner cutting depth. MAIN OUTCOME MEASURES: Donor tissue profiles and residual bed thicknesses. RESULTS: After the first pass of the microkeratome, the average cut thickness using the 250-µm cutting head was 342.5 ± 14.8 µm (range, 332 to 353 µm), that using the 300-µm head was 343.8 ± 39.2 µm (range, 315 to 411 µm), and that with the 350-µm head was 467.7 ± 50.1 µm (range, 419 to 519 µm). We used the 200-µm cutting head only once with a cut depth of 210 µm. For the second pass, when using the 110-µm head, the cutting depth averaged to 167.8 ± 28.8 µm (range, 133 to 203 µm). The 130-µm cutting head yielded a cut depth of 199.7 ± 24.4 µm (range, 180 to 227 µm). Two corneas were perforated during the second pass. The average final thickness of the residual bed was 121 ± 32.2 µm (range, 52 to 160 µm). CONCLUSIONS: Double-pass harvest for ultra-thin Descemet stripping automated endothelial keratoplasty could improve optical outcomes by obtaining donor Descemet stripping automated endothelial keratoplasty tissue with thinner residual beds. Further studies are needed with larger sample sizes to establish algorithms for appropriate cutting head thickness in each pass. Potential additional endothelial cell loss with the second pass of the microkeratome also should be evaluated.

Race- and sex-related differences in retinal thickness and foveal pit morphology.

PURPOSE: To examine sex- and race-associated differences in macular thickness and foveal pit morphology by using spectral-domain optical coherence tomography (SD-OCT). METHODS: One hundred eighty eyes of 90 healthy patients (43 women, 47 men) underwent retinal imaging with spectral-domain OCT. The lateral scale of each macular volume scan was corrected for individual differences in axial length by ocular biometry. From these corrected volumes, Early Treatment Diabetic Retinopathy Study (ETDRS) grids of retinal thickness were generated and compared between the groups. Foveal morphology was measured with previously described algorithms. RESULTS: Compared with the Caucasians, the Africans and African Americans had reduced central subfield thickness. Central subfield thickness was also reduced in the women compared with the men, although the women also showed significant thinning in parafoveal regions. There was no difference between the sexes in foveal pit morphology; however, the Africans/African Americans had significantly deeper and broader foveal pits than the Caucasians. CONCLUSIONS: Previous studies have reported race- and sex-associated differences in macular thickness, and the inference has been that these differences represent similar anatomic features. However, the data on pit morphology collected in the present study reveal an important and significant variation. Between the sexes, the differences are due to global variability in retinal thickness, whereas the variation in thickness observed between the races appears to be driven by differences in foveal pit morphology. These differences have important implications for the use of SD-OCT in detecting and diagnosing retinal disease.