Mutations in collagen, type XVII, alpha 1 (COL17A1) cause epithelial recurrent erosion dystrophy (ERED).

Corneal dystrophies are a clinically and genetically heterogeneous group of inherited disorders that bilaterally affect corneal transparency. They are defined according to the corneal layer affected and by their genetic cause. In this study, we identified a dominantly inherited epithelial recurrent erosion dystrophy (ERED)-like disease that is common in northern Sweden. Whole-exome sequencing resulted in the identification of a novel mutation, c.2816C>T, p.T939I, in the COL17A1 gene, which encodes collagen type XVII alpha 1. The variant segregated with disease in a genealogically expanded pedigree dating back 200 years. We also investigated a unique COL17A1 synonymous variant, c.3156C>T, identified in a previously reported unrelated dominant ERED-like family linked to a locus on chromosome 10q23-q24 encompassing COL17A1. We show that this variant introduces a cryptic donor site resulting in aberrant pre-mRNA splicing and is highly likely to be pathogenic. Bi-allelic COL17A1 mutations have previously been associated with a recessive skin disorder, junctional epidermolysis bullosa, with recurrent corneal erosions being reported in some cases. Our findings implicate presumed gain-of-function COL17A1 mutations causing dominantly inherited ERED and improve understanding of the underlying pathology.

Underestimation of intraocular pressure after photorefractive keratectomy: a biomechanical analysis.

Excimer laser surgery, to correct corneal refraction, induces changes in corneal thickness and curvature. Both factors can cause measurement errors when determining intraocular pressure (IOP). This study evaluates effects of photorefractive keratectomy (PRK) on IOP measurements, using Goldmann applanation tonometry (GAT) and Applanation resonance tonometry (ART), in an in vitro model. Six porcine eyes was enucleated and pressurised to a constant IOP=30 mmHg. After removal of the epithelium, the eyes were PRK-treated for a total of 25 dioptres. The measured IOP decreased 13.2 mmHg for GAT and 9.0 mmHg for ART. The total underestimation by GAT was larger than for ART, and a part of the ART underestimation (3.5 mmHg) was assigned to sensitivity to the change in corneal surface structure resulting from the removal of epithelium. The flat contact probe of GAT, as compared with the convex tip of ART, provided explanation for the difference in IOP measurement error after PRK.

Posterior corneal astigmatism in refractive lens exchange surgery.

PURPOSE: To assess the anterior, posterior and total corneal spherical and astigmatic powers in patients undergoing refractive lens exchange (RLE) surgery. METHODS: In 402 consecutive patients planned for RLE at Koskelas Eye Clinic, Luleå, Sweden, right eye data from pre- and postoperative subjective refraction, preoperative IOLMaster(®) biometry and Pentacam HR(®) measurements were collected. Postoperative Pentacam HR(®) data were collected for 54 of the patients. The spherical and astigmatic powers of the anterior and posterior corneal surfaces and for the total cornea were assessed and compared, and surgically, induced astigmatism was calculated using vector analysis. RESULTS: The spherical power of the anterior corneal surface was 48.18 ± 1.69D with an astigmatic power of 0.83 ± 0.54D. The corresponding values for the posterior surface were -6.05 ± 2,52D and 0.26 ± 0.15D, respectively. The total corneal spherical power calculated with ray tracing was 42.47 ± 2.89D with a 0.72 ± 0.48D astigmatic power, and the corresponding figures obtained by estimating the posterior corneal surface were 43.25 ± 1.51D (p < 0.001) with a 0.75 ± 0.49D astigmatic power (p = 0.003). In eyes with anterior astigmatism with-the-rule, the total corneal astigmatism is overestimated if the posterior corneal surface is estimated; in eyes, with against-the-rule astigmatism it is underestimated. Had the posterior corneal surface been measured in this material, 14.7% of the patients would have received a spheric instead of a toric IOL, or vice versa. CONCLUSION: Estimating the posterior corneal surface in RLE patients leads to systematic measurement errors that can be reduced by measuring the posterior surface. Such an approach can potentially increase the refractive outcome accuracy in RLE surgery.

Finnish experiences of health monitoring: local, regional, and national data sources for policy evaluation.

BACKGROUND: Finland has a long tradition of gathering information about the health and welfare of the adult population. DESIGN: Surveys and administrative registers form the basis for national and local health monitoring in Finland. RESULTS: Different data sources are used in Finland to develop key indicators, which can be used to evaluate how the national health policy targets have been met in different parts of the country and in different population subgroups. Progress has been shown in chronic disease risk factors, such as smoking reduction. However, some health policy targets have not been met. Socioeconomic health differences, for example, have remained large compared with other European countries. CONCLUSION: Although data availability for key health indicators is good in Finland, there is a need for wider and more comprehensive use of this information by political decision-makers and healthcare professionals.

Epidemiology and outcomes in refractive lens exchange surgery.

PURPOSE: To assess demographics and refractive outcomes in patients undergoing refractive lens exchange surgery (RLE), with a population of cataract patients as a reference. METHODS: A RLE cohort from a private eye clinic (n = 675) and a cataract cohort from the outcome registration of the Swedish National Cataract Register were studied and compared from an epidemiological perspective regarding age, gender, preoperative refraction and postoperative refractive outcome. RESULTS: The RLE patients were younger (52.1 ± 7.7 versus 73.84 ± 9.32 years) with a smaller percentage of women (45.28% versus 60.46%; p < 0.001) and were more often myopic than the cataract patients. Astigmatism and hyperopia did not differ between the cohorts. Uncorrected visual acuity after RLE equalled the best corrected visual acuity in best cases after cataract surgery. The absolute biometry prediction was more accurate in RLE (0.17 ± 0.27 D versus 0.40 ± 0.58 D; p < 0.001), particularly in patients given a customized toric IOL (0.12 ± 0.27 D; p < 0.05). In cataracts, the Haigis' formula showed higher accuracy than the SRK/T formula (0.39 ± 0.53 D versus 0.43 ± 0.61 D; p < 0.01). Postoperatively after RLE, Laser Epithelial Keratomileusis was performed in 9.04% and Yttrium Aluminium Garnet capsulotomy in 7.41% of the eyes. Other reoperations were performed in three cases, and five postoperative retinal detachments occurred after RLE. CONCLUSION: Compared with patients undergoing cataract surgery, we see many similarities, but also many interesting differences in patients undergoing RLE. Basic information about the growing population choosing to undergo RLE can help us plan future ophthalmic care.

Gender differences in refractive prediction in refractive lens exchange surgery.

PURPOSE: To compare the refractive outcomes after refractive lens exchange (RLE) surgery with regards to gender and intraocular lens (IOL) power calculation formula. METHODS: A cohort of consecutive patients operated with bilateral same-day RLE surgery at a private eye clinic (n = 512) was studied. Target refraction was emmetropia in all cases and Haigis formula was used for all IOL power calculations. One month after surgery, subjective refraction was assessed and the absolute refractive prediction error (RPEAbs), as well as the refractive prediction error with correct signs (RPESign), was calculated, as were the refractive outcomes with the SRK/T formula. RESULTS: For the whole cohort, the Haigis formula rendered a significantly smaller RPEAbs than the SRK/T formula (0.16 ± 0.26 D vs 0.32 ± 0.30 D; p<0.001). No gender difference in RPEAbs was seen. A slight myopic error was seen with the SRK/T formula in women, and a slight hyperopic error in men (-0.06 ± 0.47 D vs + 0.16 ± 0.39 D; p<0.001). No similar gender difference was seen with the Haigis formula (+0.05 ± 0.29 D vs +0.05 ± 0.31 D; p = NS). Axial length, anterior chamber depth, and corneal steepness differed significantly between the sexes. CONCLUSIONS: The Haigis formula generally performed better in this RLE cohort. The SRK/T formula generates a small myopic error in women and a hyperopic error in men, associated with flatter corneas, longer axial lengths, and deeper anterior chambers in the latter.

A paired comparison of intracameral mydriatics in refractive lens exchange surgery.

PURPOSE: To compare the efficacy and intra-operative safety of intracameral mydriatics to topical mydriatics in patients undergoing refractive lens exchange (RLE) surgery. METHODS: In a randomized intra-individually comparing study performed at Koskelas Eye Clinic, Luleå, and Department of Clinical Sciences/Ophthalmology, Umeå University Hospital, Umeå, Sweden, 56 patients undergoing same-day bilateral RLE were included. Pupils were randomly dilated with topical mydriatics in one eye and intracameral mydriatics in the fellow eye. Pupil sizes were recorded intra-operatively throughout the procedures. Perceived pain/discomfort and glare were assessed immediately postoperatively using a visual analogue scale from 0 to 10. RESULTS: Topical mydriatics and intracameral mydriatics both give satisfactory pupil dilation in routine RLE. However, there was noticeable iris billowing in 17 eyes dilated with topical mydriatics but only one eye with intracameral mydriatics (p < 0.001). Pupils were initially slightly larger in the topical mydriatics group but contracted during surgery. There was no perceived difference with regards to glare, pain or discomfort between the treatments. The surgeon graded intracameral mydriatics eyes as easier to operate on. CONCLUSION: Both topical mydriatics and intracameral mydriatics give satisfactory mydriasis for RLE, but pupil constriction and iris billowing are more pronounced with topical mydriatics.

Change in intraocular pressure measurement after myopic LASEK: a study evaluating goldmann, pascal and applanation resonance tonometry.

PURPOSE: To prospectively evaluate 3 tonometry methods--the gold standard, Goldmann applanation tonometry, a new method, Pascal dynamic contour tonometry (PDCT), and a method under development, applanation resonance tonometry (ART)--with respect to intraocular pressure (IOP) measurements before, 3 and 6 months after laser-assisted subepithelial keratectomy (LASEK). MATERIALS AND METHODS: One randomly assigned eye of each of 53 healthy individuals, who underwent LASEK surgery for myopia was studied. Visual acuity, central corneal thickness, corneal curvature, and IOP were measured at each visit. Six IOP measurements/methods with 5 minutes pause between methods were performed. RESULTS: All tonometry methods measured a significantly lower IOP after LASEK correction by a mean of -3.1 diopters. The IOP reduction was largest after 6 months for Goldmann applanation tonometry (-1.7 ± 1.8 mm Hg) followed by ARTstat (-1.2 ± 1.5 mm Hg), PDCT (-1.1 ± 1.6 mm Hg), and ARTdyn (-1.0 ± 1.5 mm Hg). The reduction of IOP did not differ significantly between different methods (P=0.11). There was a significant further reduction of measured IOP for PDCT between 3 and 6 months (-0.5 ± 1.0 mm Hg). Uncorrected visual acuity improved significantly between 3 and 6 months postoperatively from 1.32 ± 0.28 to 1.43 ± 0.27. CONCLUSIONS: All tonometry methods measured a significant, but low, reduction of IOP 3 and 6 months after LASEK. Further change in visual acuity and IOP measurements between 3 and 6 months suggest a still ongoing postoperative process.

Change in intraocular pressure measurement 2 years after myopic laser-assisted subepithelial keratectomy.

PURPOSE: To evaluate intraocular pressure (IOP) measurements 24 months after laser-assisted subepithelial keratectomy (LASEK) with 3 tonometry methods-Goldmann applanation tonometry (GAT), Pascal dynamic contour tonometry (DCT), and applanation resonance tonometry (ART)-and to compare them with measurements taken preoperatively and 3 and 6 months postoperatively. SETTING: Department of Ophthalmology, Umeå University, Umeå, Sweden. DESIGN: Prospective randomized single-center. METHODS: One randomized eye per person from myopic healthy individuals who had LASEK was included. Visual acuity, central corneal thickness (CCT), corneal curvature, and IOP were measured at all time points. Six IOP measurements were performed per method, with a 5-minute lapse between methods. RESULTS: The study evaluated 38 eyes. Two years after LASEK, dynamic ART was the only method that did not measure significantly lower IOP than before LASEK (mean -0.2 mm Hg ± 1.6 [SD]). The greatest difference was with GAT (mean -1.9 ± 1.7 mm Hg) followed by static ART (mean -1.2 ± 1.6 mm Hg) and then DCT (mean -0.9 ± 1.3 mm Hg). All methods measured significantly lower IOP at 3 months and 6 months. CONCLUSIONS: Dynamic ART, which analyses IOP measurement during indentation, showed no significant difference in measured IOP after 24 months. The convex tip of the ART device and the continuous sampling of data during corneal indentation seem to be factors in why dynamic ART was less affected by corneal properties and therefore more suitable for IOP measurement in LASEK-treated eyes, although this must be confirmed in larger trials.