[Purkinje images in slit lamp videography : Video article]. / Purkinje-Bilder in der Spaltlampenvideographie : Videobeitrag.

Reflexes that accompany every examination with the slit lamp are usually regarded as annoying and therefore do not receive much attention. In the video available online, clinical information "hidden" in the Purkinje images is analyzed according to our concept of slit lamp videography. In the first part of the video, the four Purkinje images which are reflections on the eye's optical surfaces are introduced for the phakic eye. In the pseudophakic eye, however, the refracting surfaces of the intraocular lens (IOL) have excellent optical properties and therefore form Purkinje images 3 and 4 of high quality. Especially the third Purkinje image from the anterior IOL surface, which is usually hardly visible in the phakic eye can be detected deep in the vitreous, enlarged through the eye's own optics like a magnifying glass. Its area of reflection can be used to visualize changes of the anterior segment at high contrast. The third Purkinje image carries valuable information about the anterior curvature and, thus, about the power of the IOL. If the same IOL type is implanted in a patient, often a difference between right and left of 0.5 diopter in its power can be detected by the difference in size of the respective third Purkinje image. In a historical excursion to the "prenatal phase" of the slit lamp in Uppsala, we show that our most important instrument in clinical work was originally designed for catoptric investigations (of specular reflections). Accordingly A. Gullstrand called it an ophthalmometric Nernst lamp.

[Screening for glaucoma by blue light-pattern ERG and OCT--are the methods comparable?]. / Glaukomscreening mit dem blaulicht-muster-ERG und dem OCT--sind beide verfahren gleichwertig?

BACKGROUND: Up to now, several examinations are necessary to identify early glaucoma. It is also possible to analyse the peripapillary retinal nerve fibre layer thickness by means of OCT. The loss of retinal ganglion cells can be measured by pattern ERG, therefore this method could be used for the detection of early glaucoma. This study compares the results of the blue light-pattern ERG with the Stratus OCT for glaucoma early recognition. PATIENTS AND METHODS: We studied 30 healthy test persons, 20 patients with glaucoma and 20 patients with suspected glaucoma. Each group was examined using eye pressure measurements, funduscopy, perimetry, pachymetry und analysing the retinal nerve fibre layer by the Stratus OCT. The diagnostic work-up was completed by the pattern ERG and an upgrade with a blue light filtering glass. The results of the blue light-pattern ERG and the OCT ("healthy" or "pathological") were compared in a cross table and the agreement between these two raters was measured by the Cohen's kappa coefficient. RESULTS: Pattern ERG and blue light-pattern ERG decrease with advancing age. After developing an age-matched calibration graph we defined standard values up to the age of 56 years. All included subjects were classified by Stratus OCT and blue light-pattern ERG as healthy. We recognised a significant reduction of the retinal nerve fibre layer thickness and the amplitude in the pattern ERG in the cluster of glaucoma patients. For most of them, a blue light-pattern ERG could not be recorded. Nine out of 40 glaucoma suspect eyes were judged as "pathological". Regarding the amplitudes of the blue light-pattern ERG 25 of 28 eyes under suspicion of glaucoma were assigned as "healthy". With the aid of the cross table we estimated a Cohen's kappa of 0.4. The sensitivity of the blue light-pattern ERG was computed to be 70 % and the specificity to be 97.7 %. For the OCT we calculated the sensitivity to be 50 % and the specificity to be 100 %. CONCLUSION: The blue light-pattern ERG correlates in 87 % of our cases with the OCT. Healthy test persons are certainly identified just as well as definitely glaucomatous patients. To distinguish people suspected of early glaucoma the blue light-pattern ERG can be used as an additional, fast and economic diagnostic procedure.

[A new haploscopic test device excludes blinking induced monocular perception]. / Ein neues haploskopisches Testverfahren verhindert monokulare Perzeption durch Blinzeln.

BACKGROUND: Haploscopic tests like the pola-test are used to detect functional loss of vision, aggravation or simulation. They aim at confusing the tested person about the relation of disparate monocular visual perceptions to the right and left eyes. The haploscopic confusion can be overcome easily by single sided blinking. Other investigators have faced this problem by presenting optotypes very briefly, thus excluding blinking artefacts. We introduce a new device for shutting off the optotype projection whenever blinking occurs. MATERIALS AND METHODS: A newly developed mechanism slightly presses small lever-switches onto each upper eyelid of a test person while performing the pola test. The levers move up and down following eyelid movements. Lid closure triggers a shut off of the optotype projector. The device was tested on 30 persons. RESULTS: The device worked properly on 59/60 eyes. 24/30 persons did not realize the haploscopic confusion at the beginning, but 6/30 did right away. 18/30 would not realize the haploscopic confusion even after some experience. CONCLUSIONS: The new device worked on nearly all patients and effectively kept most of them from overcoming the haploscopic confusion. It is a useful upgrading for haploscopic tests, making them applicable even in repeated examinations. It should be helpful to detect single-sided functional loss of vision.

[Computer animated childrens pictures for vision testing]. / Computeranimierte Kinderbilder zur Visusbestimmung.

BACKGROUND: Testing visual acuity is a very important element especially in the ophthalmological examination of children. The diagnosis and procedure of subsequent therapy depend on the results of vision testing. Some children achieve false low results in visual acuity because of reduced compliance. This can lead to incorrect diagnoses and false therapies. PATIENTS AND METHODS: We developed a computer animated version of the visual acuity chart "Echelle Animaux". This new test was first performed on 16 normal adult volunteers and then on 16 children who achieved as good visual scores in conventional tests as the control group. After that we tested 25 children with low compliance. RESULTS: Most of the tested children were more motivated and attentive when performing the new test. In 9 out of 25 children the measured visual acuity scores were clearly better than in the conventional test. CONCLUSION: The animation of optotypes has a favourable effect on the motivation of children. The problem of reduced compliance and concentration can be reduced. The visual acuity scores can be improved by eliminating mistakes caused by low motivation.

[Modified moisture chamber]. / Modifizierter Uhrglasverband.

BACKGROUND: Moisture chambers can protect the eye in corneal lubrication or eyelid closure disorders. However, in cases with protrusio bulbi or pronounced chemosis conjunctivae direct damaging contact of the cornea or conjunctiva on the one hand and the inside of the moisture-chamber-bandage on the other hand are possible. Since commercial moisture-chamber-bandages are not available with different internal radii, new methods are necessary to increase the distance between the bandage and the eye. MATERIAL AND METHODS: A special pressure relieving foam dressing used in the therapy and prophylaxis of decubitus was prepared in such a way that a periocular attachment was enabled and an opening for the eye was left blank. This central opening was covered with a commercial moisture-chamber-bandage. Five test persons and two ventilated patients with protrusio bulbi and manifest lagophthalmus were treated with the modified moisture chamber. The relative humidity within the bandage was measured. RESULTS: The modified moisture chamber allows an individual adaptation to the periocular shape of the face and rises the level of the monoculus for about 7 mm. The internal relative humidity was for eight hours at 98% in both test persons and patients. All test persons felt more comfortable with the modified moisture chamber on their skin. CONCLUSIONS: The presented modified moisture chamber is a derivative of the commercial monoculus bandage for patients with sensitive protrusio bulbi.

[New permanent humidity chamber in dry eye disorders]. / Neue Permanent-Feuchtkammer bei Benetzungsstörungen.

BACKGROUND: In corneal lubrication or eyelid closure disorders it may be necessary to apply a monoculus to protect the eye from drying out. Changing the monoculus involves dermal irritation. Furthermore, because the monoculus is not completely airtight, the desired humidity is not achieved. INSTRUMENT: We introduce a tape-free permanent humidity chamber fastened to a spectacle frame that achieves a relative humidity of more than 98% even over a long period of time. PATIENTS/TESTED PERSONS: Five test persons and two patients with lagophthalmus were treated with a monoculus and with the permanent humidity chamber. Comparative measurements of the humidity achieved with the two methods were done. RESULTS: For both test persons and lagophthalmus patients the permanent humidity chamber is a good alternative to the monoculus, because it maintains a humidity of more than 98% r/H over a period of eight hours or longer. It consequently provides much better conditions for successful treatment and additionally minimizes skin irritation.