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PubMed2000

The complete form of X-linked congenital stationary night blindness is caused by mutations in a gene encoding a leucine-rich repeat protein.

X-linked congenital stationary night blindness (XLCSNB) is characterized by impaired scotopic vision with associated ocular symptoms such as myopia, hyperopia, nystagmus and reduced visual acuity. Genetic mapping in families with XLCSNB revealed two different loci on the proximal short arm of the X chromosome. These two genetic subtypes can be distinguished on the basis of electroretinogram (ERG) responses and psychophysical testing as a complete (CSNB1) and an incomplete (CSNB2) form. The CSNB1 locus has been mapped to a 5-cM linkage interval in Xp11.4 (refs 2,5-7). Here we construct and analyse a contig between the markers DXS993 and DXS228, leading to the identification of a new gene mutated in CSNB1 patients. It is partially deleted in 3 families and mutation analysis in a further 21 families detected another 13 different mutations. This gene, designated NYX, encodes a protein of 481 amino acids (nyctalopin) and is expressed at low levels in tissues including retina, brain, testis and muscle. The predicted polypeptide is a glycosylphosphatidylinositol (GPI)-anchored extracellular protein with 11 typical and 2 cysteine-rich, leucine-rich repeats (LRRs). This motif is important for protein-protein interactions and members of the LRR superfamily are involved in cell adhesion and axon guidance. Future functional analysis of nyctalopin might therefore give insight into the fine-regulation of cell-cell contacts in the retina.

Amino Acid Motifs↗
PubMed1998

Loss-of-function mutations in a calcium-channel alpha1-subunit gene in Xp11.23 cause incomplete X-linked congenital stationary night blindness.

X-linked congenital stationary night blindness (CSNB) is a recessive non-progressive retinal disorder characterized by night blindness, decreased visual acuity, myopia, nystagmus and strabismus. Two distinct clinical entities of X-linked CSNB have been proposed. Patients with complete CSNB show moderate to severe myopia, undetectable rod function and a normal cone response, whereas patients with incomplete CSNB show moderate myopia to hyperopia and subnormal but measurable rod and cone function. The electrophysiological and psychophysical features of these clinical entities suggest a defect in retinal neurotransmission. The apparent clinical heterogeneity in X-linked CSNB reflects the recently described genetic heterogeneity in which the locus for complete CSNB (CSNB1) was mapped to Xp11.4, and the locus for incomplete CSNB (CSNB2) was refined within Xp11.23 (ref. 5). A novel retina-specific gene mapping to the CSNB2 minimal region was characterized and found to have similarity to voltage-gated L-type calcium channel alpha1-subunit genes. Mutation analysis of this new alpha1-subunit gene, CACNA1F, in 20 families with incomplete CSNB revealed six different mutations that are all predicted to cause premature protein truncation. These findings establish that loss-of-function mutations in CACNA1F cause incomplete CSNB, making this disorder an example of a human channelopathy of the retina.

Amino Acid Sequence↗
PubMed1996

Two infant vision screening programmes: prediction and prevention of strabismus and amblyopia from photo- and videorefractive screening.

Two infant vision screening programmes on total populations in the Cambridge Health District have been designed to identify manifest strabismus and strabismogenic and amblyogenic refractive errors at 7-9 months of age. The first, completed, programme used the isotropic photorefractor with cycloplegia together with a standard orthoptic examination. The second, current, programme uses the VRP-1 isotropic videorefractor to identify infants with accommodative lags which are followed up by refraction under cycloplegia. Both programmes show good agreement between infants identified at screening and retinoscopic refractions at follow-up, showing that photo- and videorefraction (with or without cycloplegia) can be effective methods for screening for ametropia in infants and young children. In each programme 5-6% of infants showed abnormal levels of hyperopia (> or = 3.5 D in any meridian), less than 1% showed anisometropia > or = 1.5 D; very few infants (0.25%) showed -3D myopia or greater. Less than 1% showed manifest strabismus. Hyperopic and anisometropic children entered a randomised controlled trial of partial refractive correction. All children identified at screening, alongside appropriate control groups, are extensively followed up to age 4 years. The first programme has found that children who were hyperopic in infancy were 13 times more likely to become strabismic, and 6 times more likely to show measurable acuity deficits by 4 years, compared with controls. Wearing a partial spectacle correction reduced these risk ratios to 4:1 and 2.5:1 respectively. The impaired acuity can be attributed, in part, to meridional amblyopia resulting from persisting astigmatism. Both hyperopic and myopic infants showed refractive changes in the direction of emmetropia between 9 months and 4 years. Wearing a partial spectacle correction did not affect this process of emmetropisation, but does provide the possibility of reducing the incidence of common pre-school vision problems.

Aging↗
PubMed2002

Characteristic ocular findings in Asian children with Down syndrome.

AIMS/PURPOSE: To identify the characteristic ocular findings in Asian children with Down syndrome. METHODS: A total of 123 Korean children with Down's syndrome between 6 months and 14 years of age were examined for ocular findings from March 1999 to April 2000. Ocular examinations including visual acuity assessment, slit-lamp biomicroscopy, ocular motility, cycloplegic refraction, and ophthalmoscopy were performed. RESULTS: The ocular findings in decreasing prevalence were the following: upward slanting of the palpebral fissure (78 patients, 63%), epicanthus (75 patients, 61%), epiblepharon (66 patients, 54%), astigmatism (38 patients, 31%), hyperopia (35 patients, 28%), myopia (31 patients, 25%), strabismus (31 patients, 25%, 18 esotropia and 13 exotropia), nystagmus (27 patients, 22%), nasolacrimal duct obstruction (21 patients, 17%), blepharoconjunctivitis (20 patients, 16%), retinal abnormalities (18 patients, 15%), cataract (four patients, 13%), and glaucoma (one patient, 0.8%). Brushfield spots and keratoconus were not found. CONCLUSIONS: Asian children with Down syndrome demonstrate unreported, high incidence of epiblepharon, the high rate of exotropia, and essentially no notable Brushfield spots, which are in contrast to the ocular findings in Caucasian patients with Down syndrome.

Adolescent↗
PubMed1999

Use of eye care services by older Australians: the Blue Mountains Eye Study.

PURPOSE: To assess utilization of eye care services in an older Australian population. METHODS: The Blue Mountains Eye Study examined 3654 permanent residents aged 49 years or older from two New South Wales postcode areas. At interview, we collected information about past attendance to eye care practitioners, demographic and socio-economic status variables and past medical and eye history. Full-time optometric and part-time ophthalmic services were available in this community. RESULTS: Almost all participants (99%) had seen either an ophthalmologist or optometrist in the past, with 62, 27, 7 and 3% having last attended in the last 2, 2-5, 5-10 and > 10 years, respectively. Among those participants (2251) who had been seen in the last 2 years, 50.2% (1131) last saw an ophthalmologist, 48.6% (1094) last saw an optometrist and 26 (1.2%) could not state whom they saw. After adjusting for age and sex, factors statistically significantly associated with attending an ophthalmologist included older age, female gender, higher socio-economic status, moderate to high myopia and presence of systemic disease (diabetes, hypertension) or any significant eye pathology. Factors statistically significantly associated with attending an optometrist were younger age, living alone, not currently married, being able to go out alone, having better presenting visual acuity, hyperopia and absence of diabetes or significant eye pathology, including moderate to high myopia. CONCLUSIONS: Findings from this study indicate that whether people use eye care services and whom they visit is mainly driven by need factors. Although there was considerable overlap, this study found relatively appropriate utilization of eye care services by this population.

Age Distribution↗
PubMed1999

The influence of interactions between accommodation and convergence on the lag of accommodation.

Several models of myopia predict that growth of axial length is stimulated by blur. Accommodative lag has been suggested as an important source of blur in the development of myopia and this study has modeled how cross-link interactions between accommodation and convergence might interact with uncorrected distance heterophoria and refractive error to influence accommodative lag. Accommodative lag was simulated with two models of interactions between accommodation and convergence (one with and one without adaptable tonic elements). Simulations of both models indicate that both uncorrected hyperopia and esophoria increase the lag of accommodative and uncorrected myopia and exophoria decrease the lag or introduce a lead of accommodation in response to the near (40 cm) stimulus. These effects were increased when gain of either cross-link, accommodative convergence (AC/A) or convergence accommodation (CA/C), was increased within a moderate range of values while the other was fixed at a normal value (clamped condition). These effects were exaggerated when both the AC/A and CA/C ratios were increased (covaried condition) and affects of cross-link gain were negated when an increase of one cross-link (e.g. AC/A) was accompanied by a reduction of the other cross-link (e.g. CA/C) (reciprocal condition). The inclusion of tonic adaptation in the model reduced steady state errors of accommodation for all conditions except when the AC/A ratio was very high (2 MA/D). Combinations of cross-link interactions between accommodation and convergence that resemble either clamped or reciprocal patterns occur naturally in clinical populations. Simulations suggest that these two patterns of abnormal cross-link interactions could affect the progression of myopia differently. Adaptable tonic accommodation and tonic vergence could potentially reduce the progression of myopia by reducing the lag of accommodation.

Accommodation, Ocular↗
PubMed2002

Referral rates for a functional vision screening among a large cosmopolitan sample of Australian children.

The aim of this study was to investigate the incidence of functional vision problems in a large unselected cosmopolitan population of primary school-age children and to investigate whether constant clinical criteria for functional vision problems would be implemented by the practitioners involved in the screening. Refractive errors, near point of convergence, stereopsis, strabismus, heterophoria and accommodative facility were assessed for 2697 children (3-12 years) of varying racial backgrounds living in Australia. The spherical component of the refractive error ranged from -7.75 to +9.50 D (mean +0.54 D, +/-0.79) with a distribution skewed towards hypermetropia; astigmatism ranged from 0 to 4.25 D (mean -0.16 D, +/-0.35). There was a trend towards less hypermetropia and slightly more astigmatism with age. Mean near point of convergence was 5.4+/-2.9 cm, heterophoria at far and near was 0.12+/-1.58delta exophoria and 1.05+/-2.53delta exophoria, respectively, 0.55% of children exhibited vertical phoria at near >0.5delta, accommodative facility ranged from 0 to 24 cycles per minute (cpm) (mean 11.2 cpm, +/-3.7), stereopsis varied from 20 to 800 s (") of arc with 50% of children having 40" or better. The prevalence of strabismus was particularly low (0.3%). Twenty percent of the children were referred for further assessment based on criteria of one or more of: stereopsis >70", accommodative facility <8 cpm, near point of convergence (NPC) >9 cm, near exophoria >10delta or near esophoria >5delta, shift in eso or exophoria > or = 4delta between distance and near, astigmatism > or = 1 D, myopia more than -0.75 D, or hyperopia >+1.50 D. Post-hoc analysis of the record cards seeking the reason for further assessment indicates that referrals appear to have been based upon clinical intuition rather than on a set number of borderline or unsatisfactory results.

Accommodation, Ocular↗
PubMedDate not supplied

Cranioectodermal dysplasia: a new patient with an inapparent, subtle phenotype.

Cranioectodermal dysplasia is a rare syndrome characterized by craniofacial and skeletal anomalies and ectodermal dysplasia. Life-threatening associated conditions (i.e., kidney failure and abnormal regulation of the parathyroid-bone axis) can also develop. We report a patient whose features are suggestive of an inapparent, subtle phenotype of the syndrome. The patient is a 4-year-old girl with only dolichocephaly and clinodactyly; microdontia, hypodontia, and taurodontia (i.e., cone-shaped teeth); anteverted nares, full cheeks, and everted lower lip; epicanthal folds, hypertelorism and hyperopia; and corpus callosum hypoplasia. She has no rhizomelic limb shortening or hair abnormalities. In view of the rarity of the cranioectodermal dysplasias, the variability of the phenotype, and the uncertain outcome of some previously described patients, we believe this inapparent, subtle case should reported to enable better understanding and treatment of this rare syndrome.

Bone and Bones↗
PubMed2001

[Near vision after implantation of monofocal versus multifocal intraocular lenses].

AIM: Object of this study was to compare the near visual acuity between eyes with monofocal intraocular lens (MONO) and myopic target refraction in comparison with eyes after refractive multifocal intraocular lens (MIOL) implantation and emmetropic to slight hyperopic target refraction. PATIENTS AND METHOD: 89 eyes of 83 patients underwent cataract surgery, in 49 eyes a MONO (SI-40NB, Allergan) was implanted, in 40 eyes a refractive MIOL (SA-40N, Allergan). At day 2 after surgery and after 5 months the uncorrected near visual acuity, the near visual aculty with distance correction and with an addition of +3 diopters (D) were determined. The refractive outcome targeted in case of MIOL implantation was emmetropia to slight hyperopia and myopia for the MONO subjects. The eyes with MONO were classified in 4 categories depending on their postoperative refractive error (spherical equivalent, SE): category 1 with SE +1 to > 0 D, category 2 with SE 0 to > -1 D, category 3 with SE -1 to > -2 D and category 4 with a SE -2 to > -3 D. RESULTS: We found a statistically significant better uncorrected near visual acuity in eyes with MIOL than in MONO subjects for category 1-3. In category 4 there was no statistically significant difference between MONO and MIOL. With best distance correction near visual acuity in MIOL was statistically significant better than in all 4 MONO categories. After adding 3 D, there was no statistically significant difference between the groups. CONCLUSION: Even in case of a myopic target refraction near visual acuity in eyes of the MONO group was statistically significant worse than in the eyes of the MIOL group. Only in case of postoperative SE of < or = -2 D eyes of the MONO group had a near visual acuity similar to the eyes of the MIOL group. This advantage is accomplished with a decrease in the uncorrected distance visual acuity.

Aged↗
PubMed2001

[Primary open angle glaucoma in cornea plana masked by false normal applanation tonometry (Goldman) - a case report].

BACKGROUND: Cornea plana is a rare syndrome, which leads to a flat corneal curvature due to a reduced sclero-corneal angle. Depending on the regularity of the corneal astigmatism the frequently resulting hyperopia may be difficult to compensate for. Because of the flatness of the cornea the anterior chamber is also flat, the anterior chamber angle can be restricted, and the applanatory intraocular pressures (IOPs) are measured too low. A primary open angle glaucoma is therefore not diagnosed for a long time, until changes of the optic nerve head occur. Patient and methods We report on a 66-year-old male with cornea plana. Although his intraocular pressure (IOP), measured with an applanation tonometer (Goldmann), had always been normal (< 21 mm Hg), he suffered from an increasing glaucomatous atrophy of the optic disc. We carried out a complete ophthalmological investigation, including keratometry and corneal topography analysis (TMS-1, Tomey). Furthermore, visual field was determined (G1, Octopus) and the optic nerve heads were documented and analysed by papillometry. A 48-hour tension profile was worked out for both eyes including applanation and Schiötz tonometry. Results The central refractive power of the cornea was 31 diopters and the cornea seemed to be flattened on slit lamp evaluation. The glaucomatous atrophy of the optic disc was more pronounced in the OD than in the OS (OD=neuroretinal rim loss in the upper part, at the bottom and in the lateral part of the optic disc, OS=laterally distinct neuroretinal rim loss). While the anterior parts of the eye were shortened (depth of the anterior chamber was OD/OS=1.9 mm), a macrophthalmus posterior was stated (axial length OD=25.78 mm, OS=25.72 mm). However, the IOPs were measured below 21 mm Hg by applanation during the entire tension analysis, comparable values measured with the Schiötz tonometer showed values above 21 mm Hg. We converted the applanatory IOP values according to the flat corneal power, as described in literature (addition of 1 mm Hg to the applanatory values per 3 diopters decreased corneal power). The tension analysis now showed increased values, as expected after observation of the glaucomatous excavated optic nerve head. Conclusion In patients with cornea plana applanatory IOPs are measured too low. Therefore in case of very flat corneas a mathematical correction of the applanatory IOP should be carried out, in order to diagnose a primary open angle glaucoma early enough.

Aged↗
PubMed2002

[Clinical and histological studies on the intrastromal corneal ring segments (ICRS(R), Intacs(R))].

Intrastromal corneal ring segments (ICRS(R), Intacs(R)) are corneal inlays made of PMMA with an arc length of 150 degrees for the correction of low to moderate myopia. This additive and potentially reversible method has recently been developed to clinical usefulness during the last few years. Besides the historical development und the results of the US FDA studies, we focus on the results of the European experience with this technique. For the first time, long-time follow-up results (5 years from a single surgical center) are presented. Morphological changes after implantation of Intacs(R) were investigated in a series of patients by confocal microscopy. Weeks and months after implantation "lamellar channel deposits" regularly appear around the segments. This material consists of intracellular lipids (cholesterol ester, triglyceride and unesterified cholesterol), as we could show in new histological studies on rabbit eyes. New developments of this technique include short arc length segments (130 degrees ) for the correction of myopia concurrent with astigmatism and radially placed corneal inlays (Intrastromal Corneal Segments, ICS(R)) for the correction of hyperopia. In recent years, Intacs(R) have also been implanted in eyes with keratoconus and keratectasia after LASIK. These early results seem to indicate that in certain cases of early keratoconus, these implants can indeed improve corneal geometry and vision. Even in cases of regression or undercorrection after LASIK (with thin corneas), Intacs(R) seem to give promising results in selected cases. Although Intacs(R) do give comparable results regarding both safety and efficacy when compared with PRK and LASIK, this technology has not yet been widely accepted among refractive surgeons. Whether Intacs(R) will play a greater role in routine refractive surgery in the future or will just remain a special device for the correction of keratectasia, keratoconus or regression after LASIK cannot yet be decided with certainty.

Animals↗
PubMed2002

[Pitfalls of IOL power prediction after photorefractive keratectomy for high myopia -- case report, practical recommendations and literature review].

BACKGROUND AND PURPOSE: Published experience with eyes after keratorefractive correction of myopia indicates that insertion of the average keratometric readings into standard IOL power predictive formulas will frequently result in substantial undercorrection and postoperative hyperopic refraction or anisometropia after cataract surgery depending on the amount of myopia corrected previously. The purpose of this paper is to discuss the accentuated differences of various approaches to minimize IOL power miscalculations by describing a case report of a patient with excessive myopia as well as a review of the literature. PATIENT AND METHODS: A 50-year old lady presented for cataract surgery on her left eye after having PRK seven years ago elsewhere (refraction - 25.5 - 3.0/20 degrees, central keratometric power 43.0 diopters [D]). Central power before cataract extraction was measured to be 35.5 D (Zeiss Keratometer) and 36.5 D (TMS-1 topography analysis) and refraction was - 3.0 D (before onset of index myopia). Orbscan slit scanning topography analysis displayed an anterior surface power of 36.8 D and a posterior surface power of - 9.3 D. Total axial length was 31.93 mm (optical biometry using Zeiss IOL-Master). The contralateral eye after PRK suffering from a comparable excessive myopia had required an exchange of the IOL implant because of intolerable anisohyperopia of + 6.0 D after primary cataract extraction elsewhere. RESULTS: Corrected corneal power values for the left eye were calculated as follows: (1) spherical equivalent (SEQ) change at spectacle plane 19.0 D, (2) SEQ change at corneal plane 26.2 D, (3) separate consideration of anterior and posterior curvature 27.5 D, (4) consideration of the IOL power misprediction on the fellow eye 29.5 D, (5) subtraction of 24 % of the SEQ change at the spectacle plane from the actually measured keratometry value 29.7 D, (6) clinical estimate from regression analysis performed earlier 30.5 D, (7) change of anterior surface power 34.5 D. Deciding for a presumably "real" corneal power of 28.0 D the Haigis formula was used to aim for - 2.0 D since the patient preferred to read uncorrected. Thus, a 21.0 D IOL was implanted uneventfully in the capsular bag. The stable refraction postoperatively was - 3.5 - 1.0/20 degrees and visual acuity increased to 20/30. Therefore, the "real" power of that cornea must have been around 30 D. CONCLUSIONS: After corneal refractive surgery, various techniques to determine the current corneal power should be compared and the value around which results tend to cluster should be relied on to avoid hyperopia after cataract surgery with lens implantation. In those cases where keratometry and refraction before PRK/LASIK are available, the gold standard is still to subtract the change of the SEQ at the corneal plane from the preoperative central keratometric power, although in the present case report the subtraction of 24 % of the SEQ change at the spectacle plane from the measured corneal power value seemed to produce the best result. Pure subtraction of the SEQ change at the spectacle plane from the corneal power value before refractive surgery has to be avoided in eyes with excessive myopia. The most reliable corrected power value should be inserted in more than one modern third-generation formula (such as Haigis, Hoffer Q, Holladay 2, SRK/T) and the highest power IOL should be implanted. In all instances, the cataract surgeon has to make sure that the corrected K-reading is not wrongly re-converted within the IOL power calculation formula used.

Corneal Topography↗
PubMed2005

[Comparative results of keratometry with three different keratometers after LASIK].

BACKGROUND: Postoperative hyperopia is a frequent result of cataract surgery in eyes after previous myopic kerato-refractive surgery. One reason for the underestimation of intraocular lens (IOL) power is the wrong corneal refractive power measurement obtained by keratometers and corneal topography systems after LASIK. The aim of this study was to compare the precision of measurements of three different keratometers after LASIK. METHOD: We studied 58 eyes of 34 refractive patients aged between 20 and 51 years. The preoperative measurements and the measurements one month after LASIK were performed with the Keratometer (Zeiss), the corneal topograph (EyeSys Technologies) and the IOL-Master (Zeiss). We compared our postoperative measurement results obtained with the three keratometers with the results obtained by using the clinical history method (chm). RESULTS: The smallest mean deviation was achieved with the IOL-Master (measured mean +/- SD: 38.94 +/- 1.88 D, vs. chm: 38.35 +/- 2.13 D). The Keratometer (Zeiss) showed a larger deviation (measured: 39.12 +/- 1.76 D, chm 38.34 +/- 2.07 D) and the largest deviation was shown with the corneal topograph (measured: 39.84 +/- 1.85 D, chm: 38.86 +/- 2.10 D), which measured in mean one diopter higher than what was obtained utilizing the chm. A positive correlation between corrected myopia and the postoperative difference between the measured and calculated value for each keratometer was found. CONCLUSION: This study demonstrates that with common keratometers central corneal power is measured too high after LASIK. For IOL calculation in patients after LASIK, the wrongly positive deviation from measured central corneal power has to be taken into account.

Adult↗
PubMed2005

[Monocentric two-year results after phakic posterior chamber lens (PRL) implantation in myopic patients].

PURPOSE: Some refractive procedures such as PRK or LASIK are limited by factors, including high myopia, hyperopia, or a thin cornea. For these cases, phakic intraocular lenses have been developed. Previous models have been associated with various complications, however. In order to minimize risks involved, a new phakic posterior chamber lens (PRL, IOLTECH) has been developed. Recent data suggest a considerably lower complication rate. Our two-year results are presented. MATERIAL AND METHODS: The implanted lens (PRL) is a very thin foldable lens made of highly refractive silicone. The design allows floating of the lens and avoids contact to the natural lens. It is not fixed in the ciliary sulcus. Up to now, we have implanted this lens into 56 myopic eyes of 31 patients. Preoperative refraction was within a range of -8.5 to -21.25 D (spherical equivalent = S.E). Best corrected preoperative visual acuity was between 0.3 and 1.0. Postoperative follow-up was up to 3.5 years. In this study 44 eyes with at least 2 years follow-up were included. RESULTS: Postoperative refraction was + 0.25 to - 1.0 D (SE, one patient with intended postoperative myopia). Far visual acuity without correction was 0.4 to 1.25, far visual acuity with best correction was 0.6 to 1.25. Two cataract formations were observed, one lens had to be removed due to repeated decentration. CONCLUSIONS: The PRL lens seems to be a promising choice for refractive surgery in myopic patients unfit for corneal surgery, although more results, especially long-term follow-ups are needed.

Adult↗
PubMed2006

[How useful is the prescription of glasses in intermittent exotropia and decompensating exophoria?].

BACKGROUND: The aim of this study was to investigate the effect of full correction of the retinoscopic measurements done in cycloplegia in two groups of patients with intermittent exotropia (IE) and decompensating exophoria (DE), respectively. PATIENTS AND METHODS: 58 patients (n = 29 each of IE and DE) fulfilled the inclusion criteria: retinoscopy in cycloplegia, follow-up of at least 6 weeks, age more than 2.5 years and reliable visual acuity. Exclusion criteria were all forms of secondary and constant exotropia, A-V incomitance of high amount and eyes with amblyopia (visual acuity in far distance < 0.5). The age median of refractometry was not higher in patients with IE compared to those with DE: 7.4 (3.10; 47.8) vs. 7.3 (3.8; 40.11) years, p = 0.33. Glasses were prescribed in any case of myopia and astigmatism as well as in hyperopia of > + 0.5 dpt. RESULTS: Mean refraction of both eyes (mean value of spherical equivalent of both eyes) was higher for IE compared to DE: 0.7 +/- 1.8 (- 5.13; + 4.75) vs. 0.1 +/- 1.7 (- 5.25; + 2.5) dpt, p = 0.9. Visual acuity improved in both groups significantly: median of visual acuity in IE: 0.9 (0.3; 1.25) vs. 1.1 (0.5; 1.25), p = 0.02; in DE: 1.0 (0.4: 1.25) vs. 1.0 (0.6; 1.25), p = 0.03. Considering only patients aged over 7 years the difference stayed significant only in the group of DE: IE: median 1.0 (0.5; 1.25) to 1.0 (0.5; 1.25), p = 0.2; DE: median 1.0 (0.8; 1.25 to 1.0 (0.8; 1.25): visual acuity was nearly always 1.0 and better, p = 0.009. In hyperopic patients a significant improvement of visual acuity could be seen: in IE from median 0.9 (0.3; 1.25) to 1.1 (0.5; 1.25), p = 0.02 , in DE visual acuity: median 1.0 (0.4; 1.25) to 1.1 (0.6: 1.25), p = 0.02, as well as stereoacuity improved significantly: median 60 (30; 240)'' vs. 60 (15; 240)'', p = 0.03. In patients aged over 7 years the improvement was no longer significant in IE: p = 0.7, but stayed significant in DE: p = 0.03. There was no significant change of the angle deviation in both groups. CONCLUSIONS: According to the results of this study, full correction of refractive errors in IE and DE leads to an improvement of the visual acuity mainly due to correction of myopia and astigmatism, but not to a better compensation of the angle deviation.

Child, Preschool↗
PubMed2006

[Astigmatism in ocular neuromuscular nystagmus].

BACKGROUND: Data on refraction of patients with congenital nystagmus are not available in the literature. PATIENTS AND METHODS: We have analysed the refractive errors in a cohort of 224 consecutive patients with congenital nystagmus, aged 1-57 years. RESULTS: Refractive errors, i. e., myopia, hyperopia (> 0.50 dioptres) and astigmatism (> 1.25 dioptres), were found in 179 patients (79.91 %). Of them 8 were myopic (4.46 %), 19 were hyperopic (10.61 %) and 152 were astigmatic (84.91 %). Mean astigmatism was of 2.44 dioptres for right eyes and 2.74 dioptres for left eyes. CONCLUSIONS: Astigmatism is extremely common in congenital nystagmus. Its presence is much higher than that found in normal populations. The amount of astigmatism found in nystagmus patients is noticeable. When considering he visual difficulties of patients with nystagmus, the astigmatic component should be taken in greatest consideration. Its presence should favour early surgery for anomalous head posture. Furthermore, refractive surgery should be considered as early as possible, for improving visual potential.

Adolescent↗
PubMed1999

[Ultrasound biomicroscopy and therapy of malignant glaucoma].

BACKGROUND: Malignant glaucoma is a rarely diagnosed condition though it has been known since over one hundred years and understood to be based on an ciliary blockage since thirty years. Now it is possible to visualise pathomechanism of ciliary block by ultrasoundbiomicroscopy. PATIENTS AND METHODS: Between January 1994 and November 1998 thirteen patients with ciliary block glaucoma had been observed. Four underwent ultrasoundbiomicroscopy. RESULTS: Ciliary block glaucoma is caused by obliteration of the posterior chamber. Ultrasoundbiomicroscopy showed, that in phakic eyes the lens, in pseudophakic eyes the capsule together with the anterior vitreous membrane and in aphakic eyes the vitreous alone are the blocking agents. Hyperopia, a narrow iridocorneal angle and ciliary sulcus as well as plateau iris configuration and a history of miotics are the predisposing risks for ciliary block glaucoma, especially after additional surgery such as cataract extraction, iridotomy, iridectomy and trabeculectomy. Clinical features are always a raised intraocular tension accompanied with a flattening of the anterior chamber, which are to be differentiated from an angle closure glaucoma. This is easy, if iridectomy, irido-capsulovitreotomy or pseudophakia are present and difficult in the very rare spontaneous cases. Cycloplegics and YAG-laser iridectomy may break the ciliary block, but the most preferable therapy is lensectomy (phakic eyes) and partial removing of the anterior vitreous and a peripheral sector of lens capsule combined with an iridectomy. This is easily performed with the vitrector via pars plana. CONCLUSIONS: Ultrasoundbiomicroscopy starts to confirm the theories on ciliary block glaucoma and allows to assess the different modes of treatment. The most successful treatment is lens extraction and partial vitreo-capsulo-iridectomy via pars plana.

Aged↗
PubMed1997

[Intraoperative skiascopy for determining the refractive value of an implantable intraocular lens].

BACKGROUND: Preoperative biometry for calculation of the refractive power of intraocular lenses is not sufficiently reliable in certain cases. Most frequently inaccuracies tend to occur in highly myopic eyes. Preceding refractive procedures can also impair IOL-calculation or even make it impossible. PATIENTS: In a highly myopic patient IOL-power calculation was not possible with conventional calculation formulas due to a preexisting refractive silicone lens located between the cataractuous natural lens and the iris. In another myopic patient ultrasound measurement of axial eye length produced variable and unreliable results. Therefore retinoscopy was performed intraoperatively in the aphakic eye. Refractive power of the IOL was calculated using a new formula. For validation of the method retinoscopy was performed intraoperatively in a second group of 11 patients with unproblematic ultrasound biometry. RESULTS: In 3 eyes IOL power was chosen according to intraoperative retinoscopy. A maximal deviation of 1.25 D from the aimed refraction resulted. In the second group, the retinoscopic method produced partially considerably inaccurate results as compared to the ultrasound biometry. Inaccuracies increased with the extent of hyperopia. CONCLUSIONS: In cases of difficult or inaccurate preoperative ultrasound biometry IOL power can be estimated after intraoperative retinoscopy in the aphacic highly myopic eye. IOL power can be calculated instantly using computer programs or tables. This method additionally enables the surgeon to control the refractive result of intraocular lens implantation prior to wound closure. However this method lacks reliability in higher hyperopic eyes, as in these cases small changes in corneal vertex distance of the lens used for retinoscopy highly alter the result.

Adult↗