Michael Gräf

Examination of young children with Lea symbols

Aims: In order to establish normal values and interocular differences of visual acuity, Lea symbols were applied to neurologically and ophthalmologically normal children. Methods: 385 children (21–93 months old) were examined, within a routine check up in an urban paediatric practice where Lea symbol acuity (LS) was measured. Of these children, 90 were re-examined in hospital comparing Lea symbol acuity (LS) and Landolt C acuity (LC). Strabismus, ametropia, and any organic eye disease were excluded. Results: In the paediatric practice, LS could be measured on both eyes in 54% of the children. In the age group above 36 and 48 months the success rate was 76% and 95%, respectively. Acuity in the paediatric practice ranged from 0.1 to 2.0 (median 1.25) in the whole group. Interocular acuity difference was one line or less in 80%. In the hospital, LS and LC could be measured on both eyes of 77% and 48% of the 90 children, respectively. Cooperation increased with age. LS in the hospital ranged from 0.32 to 2.0 (median 1.0) and LC from 0.16 to 1.25 (median 0.8). Interocular difference of LS acuity was one line or less in 90%. Conclusion: Lea symbols were found to be useful for visual acuity assessment in early childhood. Significant variability of visual acuity in this age group is caused by cooperation. When monocular measurements are possible on both eyes, however, the intraindividual interocular difference of visual acuity usually does not exceed one line.

Lea symbols: visual acuity assessment and detection of amblyopia

Abstract · Objective: Lea symbols can be used for measuring visual acuity in childhood. Therefore, these symbols might be useful for early detection of amblyopia. We evaluated whether the visual acuity determined with Lea symbols (LS) corresponds to the visual acuity determined with the Landolt-C (LC). · Patients and methods: In 55 strabismic amblyopic volunteers aged 5–59 years, the monocular visual acuity of both eyes was determined using LC and LS. For comparison, the right eye of 20 healthy volunteers was examined. Single optotypes (LC, LS) were used in 55 amblyopes and crowded optotypes (LC17.2, LC2.6, CLS) in 40 amblyopes. The luminance of the test charts was 180–200 cd/m2, with a contrast >85%. The refraction of the subjects was corrected beforehand. · Results: In the 40 amblyopic eyes tested under each condition, LS exceeded CLS and LC by about 1 line (dB), LC17.2 by 2 lines and LC2.6 by 3 lines (mean values ± SD: LS 0.62±1.8 dB, CLS 0.46±1.7 dB, LC 0.5±2.0 dB, LC17.2 0.41±2.3 dB, LC2.6 0.29±2.3 dB). The non-amblyopic fellow eyes and healthy eyes showed smaller differences (fellow eyes LS 1.32±1.1 dB, CLS 1.17±1.1 dB, LC 1.15±0.9 dB, LC17.2 1.05±0.9 dB, LC2.6 0.93±1.1 dB; healthy eyes LS 1.74±0.9 dB, CLS 1.58±0.8 dB, LC 1.48±0.6 dB, LC17.2 1.41±0.7 dB, LC2.6 1.32±1.1 dB). In the amblyopic eyes, the reduction of LC was more distinct than the reduction of LS. Fifty-two amblyopes had an amblyopia >1 dB of LC, LC17.2 and LC2.6, while 50 had an interocular acuity difference >1 dB CLS. · Conclusions: Using Lea symbols, a recognition acuity can be determined and amblyopia can reliably be detected. Due to their design, the Lea symbols are particularly suitable and recommendable for application in young children. However a slight systematic difference between LS and LC has to be considered.

Reduction of Postoperative Nausea and Vomiting by Dimenhydrinate Suppositories after Strabismus Surgery in Children

Although dimenhydrinate has been used for treatment and prevention of postoperative nausea and vomiting (PONV) since the fifties, there have been few controlled studies about its efficacy. We performed a double-blinded study of 301 children aged 4 to 10 yr who underwent strabismus surgery. Preanesthetic medication with midazolam (0.5 mg/kg) as well as application of either dimenhydrinate suppositories or a placebo preparation was performed 30 min before the induction of anesthesia. Anesthesia was induced with thiopentone (5–10 mg/kg) and vecuronium (0.1 mg/kg) and maintained with halothane (1%–2%) in N2O/O2 (65%/35%). The incidence of PONV, requirements for rescue dimenhydrinate, and time to recovery were recorded. The overall incidence of PONV was 60.1% in the placebo group and 30.7% in the dimenhydrinate group. In the dimenhydrinate group, children had to be observed in the recovery room significantly longer than those in the placebo group. Children having received dimenhydrinate were discharged from the recovery room with lower arousal scores. We conclude that the rectal administration of dimenhydrinate is effective for the prevention of PONV, although the sedative effect may require longer postoperative monitoring. Implications We performed a double-blinded, randomized study to investigate the effects of prophylactic rectal dimenhydrinate application on postoperative nausea and vomiting in children undergoing strabismus surgery. In comparison with placebo, dimenhydrinate reduced the incidence of postoperative vomiting from 60.1% to 30.7%.

Sensitivity of the MTI photoscreener for amblyogenic factors in infancy and early childhood

Abstract · Background: Screening for amblyogenic factors in infancy by pediatricians is unsatisfactory, as they hardly ever detect ametropia or microstrabismus. As photoscreening seems to be a helpful method to detect even small squint angles and refractive errors, we tested the MTI photoscreener for its sensitivity with respect to amblyogenic factors. · Patients and methods: One hundred and twelve children aged 6–48 months were first examined with the MTI photoscreener. Then each child underwent complete medical examination by an ophthalmologist and an orthoptist. The examination included the Hirschberg test (corneal reflex evaluation), the Brückner test (fundus red reflex), and, where possible, the Lang stereotest, the cover test and visual acuity assessment, as well as a motility test, biomicroscopy, ophthalmoscopy in mydriasis and refractometry in cycloplegia. Exclusion criteria were any organic pathological results, manifest strabismus, ametropia ≥2 D and astigmatism ≥1 D. An orthoptist, a pediatrician and two ophthalmologists independently evaluated the Polaroid pictures according to the criteria given in the handbook of the MTI photoscreener. · Results: For 10 children the evaluation with the MTI photoscreener was not possible despite the fact that photographs were retaken several times. Thirteen photographs showing obvious pathologic findings despite their poor quality were included. Eighty-three of the remaining 102 children failed the eye examination according to the above-mentioned criteria. The mean sensitivity of the MTI photoscreener was determined to be 82.8%. The ability to correctly identify the absence of any amblyogenic factors (specificity) was 61.8%. · Conclusions: Sensitivity was high when compared to the usually low detection rate during pediatric examinations. Due to the low specificity, effectiveness was poor. Therefore an ophthalmological examination should be included in the preventive screening during infancy and early childhood.

Objektive Prüfung der Sehschärfe

Wenn die Sehschärfe nicht anhand subjektiver Angaben bestimmt werden kann, ist eine Schätzung derselben mittels objektiver Verfahren möglich. Indikationen zur objektiven Sehschärfenschätzung können sich in der Entwicklungsdiagnostik beim Kleinkind und bei geistig behinderten Patienten ergeben. Im Rahmen eines Amblyopiescreenings ist eine objektive Sehschärfenschätzung wegen ihrer geringen Sensitivität für Amblyopie uneffektiv. Eine wichtige Indikation der objektiven Sehschärfenschätzung ist die Überprüfung von Visusangaben bei Verdacht auf Simulation oder Aggravation. Bei psychogenen Sehstörungen kommt der objektiven Sehschärfenschätzung im Hinblick auf die Erkennung und sinnvolle Behandlung der Störung anstelle überflüssiger und belastender Diagnostik wesentliche Bedeutung zu.

Information from false statements concerning visual acuity and visual field in cases of psychogenic visual impairment

Abstract · Background: If visual acuity (VA) and/or visual field (VF) is claimed to be worse than in reality, it can be difficult to estimate the actual VA/VF. This paper describes a method of proving malingering and of estimating the actual VA by statistical evaluation of the subjective responses to discrete visual stimuli. · Methods: VA is measured by using a Landolt or Snellen optotype with four possible directions. There are n (≥16) questions at each acuity level. Each direction of the optotype occurs with the same frequency. The sequence is not predictable. In testing the VF, the stimulus is presented in an unpredictable sequence but with the same frequency at each of four distinct locations outside the claimed field at the horizontal and the vertical meridian. The field is divided into four quadrants defined by the 45°–225° and 135°–315° meridians. The candidate is requested to search for the light. The target quadrant of the first eye movement is recorded. At each VA level, the distribution function of the binomial formula allows estimation of the probability Pc of ≤kc and ≥kc correct answers to n questions by mere accident. Regarding the VF, the direction of the first saccade at each stimulus presentation can be processed accordingly. · Results: If n=32 and kc=0,1,2, the chance P that this pattern is merely accidental is about 0.0001, 0.001, 0.007. Values of P≤0.01 strongly suggest that the answers were voluntarily wrong. Preference for the opposite direction can also point to psychogenic influence: If ko=15,16,17,18, P is about 0.006, 0.002, 0.0006, 0.0002. · Conclusion: Systematically false statements can yield valuable information about the actual visual functions.

Problems for ophthalmologists in the certification of blindness

ZusammenfassungHintergrundEine Analyse der 1996 in Hessen bewilligten Blindengeldanträge deckte Mängel in den entsprechenden augenfachärztlichen Bescheinigungen auf [9].MethodenUm auch Aufschluss über abgelehnte Anträge zu erhalten, verglichen wir die 117 im Jahr 2002 beim hessischen Landesblindenarzt durchgeführten Blindengutachten mit den zusammen mit dem Blindengeldantrag vorgelegten augenfachärztlichen Bescheinigungen dieser Personen (42% der Nachbegutachtungen, 5,5% der Blindengeldanträge in Hessen 2002). In den Fällen, in denen das Gutachten eine andere Einstufung ergab als in der Bescheinigung empfohlen war, wurden Visus, Gesichtsfeld, sonstige Befunde und die Untersuchungsmethodik nach Aktenlage analysiert.ErgebnisseEs wurden 75 Bescheinigungen durch das Gutachten bestätigt. Bis zur Begutachtung waren 8 Personen mit attestierter wesentlicher Sehbehinderung blind, 14 Personen, denen Blindheit bescheinigt worden war, waren der Begutachtung zufolge wesentlich sehbehindert und in 8 bzw. 12 Fällen lag weder Blindheit noch eine wesentliche Sehbehinderung vor. In 29% der Fälle war die Sehbehinderung also geringer als in der Bescheinigung attestiert.SchlussfolgerungDie Differenzen zwischen den im Gutachten nachgewiesenen und den zuvor bescheinigten Sehfunktionen waren erheblich, obwohl regelmäßig bestätigt worden war, dass das angegebene Sehvermögen den objektiven Befunden entspräche. Eine kritische Prüfung der subjektiven Angaben war in diesen Fällen offenbar nicht erfolgt. Die Anwendung einfacher subjektiver und objektiver Methoden zur Funktionsprüfung böte die Möglichkeit einer besseren Validitätskontrolle.AbstractBackgroundWe compared the medical test results of 117 persons examined by the superintendent for blindness assessment in 2002 with their certificates of blindness (5.5% of the applications, 42% of the testimonial examinations performed in Hessen in 2002).MethodsIf the ratings as „blind“ or „severely visually handicapped“ (corresponding to a visual acuity of not more than 0.02 or 0.05, resp.) differed between the medical test and the certificate, visual acuity, visual field, further findings, and the methods of assessment were analyzed on the basis of the medical records.Methods The medical test confirmed 75 certificates. Fourteen persons with a certificate of blindness were graded as severely visually handicapped by the medical test. In 8 and 12 cases, respectively, the criteria of neither blindness nor severe visual handicap were fulfilled. Eight persons with a certificate of severe visual handicap were graded as blind by the medical test.DiscussionIn 29% of the cases, the visual handicap did not reach the certified grade. Striking differences occurred between the certificate and the functions shown in the medical test. In the certificates, the declared visual handicap was regularly judged to correspond to the objective findings, but apparently in these cases symptom validity had not been critically assessed. An improvement of diagnostic validity could be achieved using relatively uncomplicated subjective and objective tests.

Heilungsverlauf und Komplikationen nach Augenmuskeloperationen

Hintergrund: Zur Inzidenz operativer und postoperativer Komplikationen bei Augenmuskeloperationen liegen unterschiedliche Mitteilungen vor. Ziel der vorliegenden Studie war es, sowohl Komplikationen als auch geringfügige pathologische Veränderungen des vorderen und hinteren Augenabschnittes nach unterschiedlichen Augenmuskeloperationen zu quantifizieren. Patienten und Methode: Es wurden prospektiv alle Patienten erfaßt, bei denen im Zeitraum Januar bis Mai 1998 an der Augenklinik für Schielbehandlung und Neuroophthalmologie Gießen eine Augenmuskeloperation durchgeführt wurde. In die Studie konnten 500 Augen von 377 Patienten im Alter von 2 bis 82 Jahren einbezogen werden. Das Spektrum der durchgeführten Eingriffe umfaßte Rücklagerungen, Resektionen, Faltungen, kombinierte Operationen, Transpositionen, Fadenoperationen und Revisionsoperationen an allen geraden und schrägen Augenmuskeln. Die Patienten wurden am Tag vor der Operation und postoperativ am ersten Tag, nach einer Woche und nach drei Monaten untersucht. Alle Komplikationen des vorderen und hinteren Augenabschnittes wurden dokumentiert und quantitativ erfaßt, teilweise erfolgte eine Gradeinteilung (0–3). Ergebnisse: Am ersten postoperativen Tag war bei 30% der Augen eine zumeist diskrete Lidschwellung auffällig. Die Bindehautschwellung und -injektion waren meist gering bis mäßig, nach einer Woche häufig nur noch gering. Der Reizzustand der Bindehaut war geringer nach Faltung als nach Resektion eines horizontalen M. rectus. Bei den Hornhautveränderungen dominierte am ersten postoperativen Tag eine Epitheliopathie (1,6%), nach 1 Woche standen diskrete Fuchssche Dellen (4,3%) im Vordergrund, die unter lokaler Therapie abheilten. Mikroskopisch erkennbare Bindehautfalten wurden überwiegend zur 3-Monats-Kontrolle (14,3%) dokumentiert, ebenso Bindehautnarben (91,3%), die i.d.R. sehr gering waren. Perforationen oder schwerwiegende Komplikationen kamen nicht vor. Schlußfolgerungen: Eine Augenmuskeloperation ist ein komplikationsarmer Eingriff, der nur selten einen erneuten Eingriff wegen organischer pathologischer Veränderungen erfordert. Zur Erkennung von Fuchsschen Dellen ist eine Kontrolluntersuchung 4–7 Tage postoperativ wichtig. Faltung eines horizontalen M. rectus führt zu weniger Bindehautreiz als Resektion.Background: Varying reports on the incidence of operative and postoperative complications following eye muscle surgery have been published. The purpose of this study was to quantify complications after various types of eye muscle surgery as well as minor pathological changes of the anterior and posterior segment. Patients and methods: This prospective study included all patients who underwent eye muscle surgery at the Department of Strabismology and Neuroophthalmology, Giessen, from January to May 1998. Five hundred eyes of 377 patients aged 2–82 years were included. The spectrum of procedures comprised: recessions, resections, tucks, R&R procedures, transpositions, bimedial retroequatorial myopexies, and revisions of rectus and oblique muscles. All patients were examined 1 day preoperatively and 1 day, 1 week, and 3 months postoperatively. Any complications and even minor pathological changes of the anterior and posterior segment were documented. Some changes were assessed by means of a score (0–3). Results: One day postoperatively, 30% of eyes had inflammatory pseudoptosis, most of them mild. Conjunctival swelling and injection were frequently mild and moderate, after 1 week mostly mild. Conjunctival irritation was more pronounced following resection than tucking. Punctate epithelial keratopathy was noted in 1.6% of cases (first postoperative day), dellen in 4.3% (first postoperative week). Three months postoperatively, 14.3% of eyes had biomicroscopically visible conjunctival folds and 91.3% had minimal conjunctival scars. None of the patients had a scleral perforation or other serious complication. Conclusions: Eye muscle surgery rarely entails complications. Revisions due to organic pathological changes are extremely rare. Possible development of dellen requires check-up 4–7 days postoperatively. Tucking of rectus muscles causes less conjunctival irritation than resection.

Kestenbaum and artificial divergence surgery for abnormal head turn secondary to nystagmus. Specific and nonspecific effects of artificial divergence

Recommendations concerning the kind and dosage of eye muscle surgery for nystagmus vary in the literature. The present paper is an evaluation of the effects of Kestenbaum and artificial divergence surgery on abnormal head posture in a retrospective study. Exclusively patients with surgery for nystagmus-related horizontal head-turn (HT), with binocular vision and without previous eye muscle surgery were considered. Of the 78 patients, aged 3 to 68 years, 52 had a HT to the left side; 47 patients were male. In the Kestenbaum group (n = 31), the preoperative HT of 30° (20–40) (median, 0.1–0.9 quantile) was reduced to 10° (0–30) by surgery of 14mm (10–20) on each eye. Four patients received further surgery. In the artificial divergence group (n = 27), the HT of 30° (25–40) was reduced to 5° (0–20) by recess-resect surgery of 10mm (7–12) on the adducted eye. Seven patients needed further surgery. In the combined Kestenbaum plus artificial divergence group (n = 20), the HT of 30° (25–40) was reduced to 7° (–5–15) by surgery of 29mm (21–37) on both eyes together. No further surgery was necessary. Kestenbaum surgery had a similar effect/dose ratio as recess-resect surgery for strabismus. If a test with base-out prisms suggests that artificial divergence is promising, this concept is preferable. It can be integrated into Kestenbaum surgery.

Vergleich von Landoltring- und ETDRS-Buchstaben-Sehschärfe bei Augengesunden und Patienten mit unterschiedlichen Augenerkrankungen

PURPOSE Results of visual acuity determination can differ depending on the stimuli being used, even if their critical details appear under the same visual angle. In this study, visual acuity measured with the Landolt C was compared to acuity measured with ETDRS charts in subjects with and without visual disorders. PATIENTS AND METHODS One hundred patients (age 8 to 90 years) with strabismus amblyopia (39), refractive amblyopia (5), cataract (24) and maculopathy (32) as well as 13 healthy volunteers (age 18 to 33 years) were examined. Retro-illuminated ETDRS 1, 2 and R charts (Lighthouse) and a retro-illuminated Landolt C chart with the same arrangement of optotypes (Precision Vision) were used. Three out of 5 optotypes in each line had to be correctly identified. In the patient group, the eyes with the lower visual acuity were tested, while the right eyes of the healthy subjects were monitored. Wrong answers were monitored and the results were noted in interpolated logMAR. RESULTS Differences between Landolt C (LC) and ETDRS acuity were only small and statistically not significant. LogMAR values (SEM in parentheses) for LC /ETDRS 1 were: entire group: 0.60 (0.04)/ 0.55 (0.04), strabismus amblyopia: 0.85 (0.08)/ 0.80 (0.08), refractive amblyopia: 0.27 (0.04)/ 0.23 (0.05), cataract: 0.57 (0.07)/ 0.51 (0.07), retinal disease: 0.67 (0.06)/ 0.61 (0.06), healthy eyes: -0.17 (0.03)/ -0.17 (0.02). The mean difference between LC and ETDRS 1 was 0.49 lines in the entire group and 0.51 lines in strabismus amblyopia in favour of ETDRS 1 values. ETDRS 2 and R charts yielded similar results. CONCLUSIONS In healthy subjects and in patients with various eye disorders including strabismus amblyopia, there was only a slight difference between visual acuity measured by ETDRS charts compared to the Landolt C. Comparing data of different settings it must be considered that in the lower visual acuity range (< 0.32), the mean ETDRS acuity of adults overestimates the Landolt C acuity by 0.5 and 1.0 line.