Mild form of oculocutaneous albinism type 1: phenotypic analysis of compound heterozygous patients with the R402Q variant of the TYR gene.

AIM: Oculocutaneous albinism type 1 (OCA1) is due to TYR mutations. c.1205G>A/p.Arg402Gln (R402Q) is a thermosensitive variant of the TYR gene that has been reported to be responsible for mild forms of OCA1. The aim of our study was to define the phenotype associated with this variant. METHODS: In our retrospective series, among 268 patients diagnosed with OCA1, 122 (45.5%) harboured one pathogenic variant of TYR, and the R402Q variant ensured to be in trans by segregation analysis in 69 patients (25.7%), constituting the 'R402Q-OCA1' group. 146 patients harboured two pathogenic variants of the TYR gene other than R402Q. Clinical records were available for 119 of them, constituting the 'Classical-OCA1' group. RESULTS: Most R402Q-OCA1 patients presented with white or yellow-white hair at birth (71.43%), blond hair later (46.97%), a light phototype but with residual pigmentation (69.64%), and blue eyes (76.56%). Their pigmentation was significantly higher than in the classical-OCA1 group. All patients from the R402Q-OCA1 group presented with ocular features of albinism. However the prevalence of photophobia (78.13%) and iris transillumination (83.87%) and the severity scores of iris transillumination, retinal hypopigmentation and foveal hypoplasia were lower in the R402Q-OCA1 group. Visual acuity was higher in the R402Q-OCA1 group (0.38±0.21 logarithm of the minimum angle of resolution vs 0.76±0.24). Investigations concerning a possible additive effect of the c.575C>A/p.Ser192 (S192Y) variant of TYR in cis with R402Q, suggested by others, showed no significant impact on the phenotype. CONCLUSION: The R402Q variant leads to variable but generally mild forms of albinism whose less typical presentation may lead to underdiagnosis.

Lessons of a day hospital: Comprehensive assessment of patients with albinism in a European setting.

Albinism is a rare genetic disease, comprising syndromic and non-syndromic forms. We assessed clinical and genetic characteristics in a prospective evaluation of 64 patients (33 children and 31 adults) seen at a specialized day hospital. Causative genetic mutations were found in TYR (23/64, 35.9%), OCA2 (19/64, 29.7%), TYRP1 (1/64, 1.6%), SLC45A2 (12/64, 18.7%), C10orf11 (1/64, 1.6%), HPS1 (3/64, 4.7%), HPS5 (1/64, 1.5%), HPS6 (1/64, 1.6%) and GPR143 (2/64, 3.1%). Causative mutations remained undetermined for one patient (1.6%). Heterogeneity for hair and skin phenotype was noted across and within the different genotypes. Skin and hair hypopigmentation did not correlate with visual impairment. The diagnosis of unrecognized syndromic forms and of cases of ocular albinism in this prospective and comprehensive series of patients with albinism in a European setting is remarkable. Photoprotection was overall good but not optimal.

Spontaneous rupture of chorioretinal coloboma in an 8-year-old child is treated by temporal fascia graft.

We report the rare case of an 8-year-old boy with spontaneous scleral perforation secondary to an isolated congenital chorioretinal coloboma. Visual acuity was 20/200 and examination revealed severe hypotony with subcapsular cataract, complete exudative retinal detachment, hypotonous optic nerve swelling, and hypotony retinal fold. In the temporal periphery, there was a chorioretinal coloboma with a central full-thickness defect. The scleral defect was successfully treated with an autologous temporalis fascia graft. One year later, and after cataract surgery, visual acuity had improved to 20/20, with normal intraocular pressure.

Evolution Profiles of Different Corneal Parameters in Progressive Keratoconus.

PURPOSE: To analyze the evolution profiles of several corneal topographic and tomographic parameters in progressive keratoconus and compare them with the kinetics of evolution of anterior keratometry. METHODS: One hundred nine eyes of 55 patients were prospectively enrolled and followed up every 3 months for at least 1 year. Forty-five corneal parameters were measured at each visit using a combined Placido-based and dual Scheimpflug imaging system. Percentage of progression between each visit was calculated for each parameter and comparisons were tested between the different variables. RESULTS: At 1 year, 11% (12/109) of eyes progressed with an increase in maximum anterior keratometry of 1 D or more. Among these eyes, the posterior maximum keratometry and vertical corneal coma had a significantly higher percentage of progression (P < 0.05) than the maximum anterior keratometry, 5.9%, 27%, and 3.2%, respectively, and occurred significantly earlier than the modifications of the anterior keratometry, at the third-, sixth-, and 12th-month visits, for vertical corneal coma, posterior keratometry, and anterior keratometry respectively. CONCLUSIONS: Modifications of the posterior surface and corneal vertical coma occurred earlier and were detectable before changes in the anterior keratometry readings in eyes with progressive keratoconus. These parameters may be relevant warning signs when monitoring progressive keratoconus.

Wavefront analysis after wavefront-guided myopic LASIK using a new generation aberrometer.

PURPOSE: To evaluate the short-term aberrometric outcomes of wavefront-guided LASIK for the correction of low to moderate myopia and myopic astigmatism using a new generation aberrometer (iDesign System; Abbott Medical Optics, Inc., Santa Ana, CA). METHODS: Charts of 92 eyes of 46 patients successively treated by wavefront-guided LASIK for myopia and/or myopic astigmatism were retrospectively reviewed at 3 months postoperatively. Aberrometric analysis of the wavefront errors was performed for a 6-mm pupil diameter to investigate the surgical induction of the total higher-order aberrations (HOAs), spherical aberrations Z41, and coma-like aberrations Z3 . Additionally, correlations between the magnitude of aberrations induced with the level of achieved correction and the preoperative amount of aberrations were tested. RESULTS: A minimal but statistically significant induction in all of the aberrations tested was observed at 3 months postoperatively (P < .01), with an increase (calculated for a 6-mm pupil) of +0.12 + 0.2, +0.06 + 0.1, and 0.05 + 0.1 pm in the root mean square (RMS) total HOA, RMS spherical aberration Z41, and RMS coma Z31, respectively. The postoperative change in aberrations was poorly correlated with both the level of achieved myopic correction for all of the aberrations tested (r < 0.3; P < .001) and the preoperative level of spherical aberrations (r = 0.3; P < .05) and coma (r = 0.46; P < .05). CONCLUSIONS: Wavefront-guided LASIK using the new generation Hartmann-Shack aberrometer allows a minimal induction of HOAs regardless of the level of myopic correction achieved or the preoperative magnitude of aberrations.

Potential of FTIR spectroscopy for analysis of tears for diagnosis purposes.

It has been widely reported that the tear film, which is crucially important as a protective barrier of the eye, undergoes biochemical changes as a result of a wide range of ocular pathology. This tends to suggest the possibility of early detection of ocular diseases on the basis of biochemical analysis of tears. However, studies of tears by conventional methods of biomolecular and biochemical analysis are often limited by methodological difficulties. Moreover, such analysis could not be applied in the clinic, where structural and morphological analyses by, mainly, slit-lamp biomicroscopy remains the recommended method. In this study, we assessed, for the first time, the potential of FTIR spectroscopy combined with advanced chemometric processing of spectral data for analysis of raw tears for diagnosis purposes. We first optimized sampling and spectral acquisition (tears collection method, tear sample volume, and preservation of the samples) for accurate spectral measurement. On the basis of the results, we focused our study on the possibility of discriminating tears from normal individuals from those of patients with different ocular pathologies, and showed that the most discriminating spectral range is that corresponding to variations of CH2 and CH3 of lipid aliphatic chains. We also report more subtle discrimination of tears from patients with keratoconus and those from patients with non-specific inflammatory ocular diseases, on the basis of variations in spectral ranges attributed notably to lipid and carbohydrate vibrations. Finally, we also succeeded in distinguishing tears from patients with early-stage and late-stage keratoconus on the basis of spectral features attributed to protein structure. Therefore, this study strongly suggests that FTIR spectral analysis of tears could be developed as a valuable and cost-saving tool for biochemical-based detection of ocular diseases, potentially before the appearance of the first morphological signs of diseases. Combined with supervised modelling methods and with use of a spectral data base acquired for representative patients, such a spectral approach could be a useful addition to current methods of clinical analysis for improvement of patient care.