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Biomedical subjects

H Gernet

Publications and source records attributed to H Gernet.

At least 19 recordsLinked to original sources
PubMed1979

The binocular confusion in unilateral aphakia.

The first 4 symptoms of binocular confusion concern primarily daytime vision and the fifth symptom concerns nighttime vision. Even with a conventional contact lens correction, symptoms of binocular confusion occur, especially with high optical aniseikonia for near or far distance. In addition, diplopia occurs in the presence of strabismus. The important result of our research is the fact that unilateral aphakes are severely disturbed by the 5 symptoms of binocular confusion described above. These disturbances can be eliminated completely with an appropriate spectacle-contact lens combination based on echometry and intraocular optics.

Adult↗
PubMed1977

[Unilateral aphakia in juveniles. Results of combined correction (author's transl)].

Eighty-one unilateral aphakies under 45 years of age, 63 of which had suffered an injury, were analyzed by echometry and intraocular optics. With the aid of a computer, the majority of cases were treated for restoration of nearly equal images in both eyes by combined correction, i.e., an appropriate spectacle -- contact lens combination with both distant and near vision in the aphakie eye taken into consideration. Results with unilateral post-traumatic aphakia (63 cases) : 31 patients with uncorrected vision and 42 with a conventional contact lens suffered from symptoms of binocular confusion as opposed to only one patient with combined correction. Of the 63 patients with uncorrected vision or with a conventional contact lens, 44 had strabismus. After optimal treatment with combined correction, with or without subsegment strabismus surgery, 19 out of 23 patients were cured of their strabismus and regained a useful and comfortable, distant and near binocular vision. Thus, for juvenile unilateral aphakics, a rather good prognosis was achieved by combined correction.

Adolescent↗
PubMed1977

[Binocular confusion in unilateral aphakia (author's transl)].

The five symptoms of binocular confusion of the unilateral aphakic patient are described. In day vision, without strabismus and without correction, the image of the aphakic eye considerbly disturbs binocular vision, though the vision is less than 20/400 (first symptom). In night traffic the uncorrected unilateral aphakic patient sees very striking light circles and within those circles of glittering dots around bright light sources of cars or around blinking indicators and stoplights (fifth symptom). The five disturbing symptoms of binocular confusion can be positivity eliminated by an appropriate combination of spectacles and contact lens (combined correction) in regard to echometry and intraocular optics.

Adolescent↗
PubMed1977

[Uniocular aphakia--conventional contact lenses and aniseikonia].

Ehrich and Kolbegger show in their papers that aniseikonia should not prevent binocular functions in a uniocular aphakia. This is contrary to our own experiences. In this paper we suggest that the results of Ehrich and Kolbegger must be worse in spite of their final conclusions. Their hypotheses are discussed.

Aniseikonia↗
PubMed1976

[Contribution on the infraocular optics (author's transl)].

Experience indicates that a person will have a comfortable vision only if the sizes of the image in both eyes are approximately equal; a tolerance of approximately 5% is acceptable for this. In other words both optical systems, consisting of a spectacle lens, a contact lens, and the eye must have approximately the same focal length. Patients who have one phacic and one aphacic eye will usually possess quite different focal lengths with conventional contact lens correction. However, with the addition of spectacles and of appropriate contact lenses on one or both eyes, the ophthalmologist has at his disposal a new variable. The given formulas and rules of thumb enable him to choose the strength of spectacles-contact lens combinations so that the patient will also have sharp vision in both eyes and regain a comfortable binocular sight. The method is illustrated by examples.

Contact Lenses↗
PubMed1976

[Intra-ocular optics and contact lens correction in unilateral aphakia].

After an explanation of intra-ocular optics, the first results of combined contact lens correction in 42 patients are reported. As opposed to the conventional type of contact lens treatment in monolateral aphakia, this method has four main advantages: 1. It enables practically identical sight in both eyes, thus providing the necessary conditions for binocular vision both at a distance and close-up. 2. The recovery of sensomotor haptics in both eyes prevents squinting, even in the case of incipient cataract of the other eye. 3. Premature lens extraction in the second eye can be postponed and delay in lens extraction in the first affected eye can be avoided. 4. In cases where dioptric aniseikonia is very marked, as in myopia, a bilateral spectacle-contact lens combination enables tolerable binocular vision to be achieved even without an aniseikonic lens. Our findings indicate that the conventional contact-lens correction of monolateral aphakia is never satisfactory in cases with a moderate to high degree of myopia and in all refraction defects in young patients. Echometry, objective measurement of aniseikonia and combined contact lens correction helps most of these patients to regain binocular vision, both close-up and at a distance. In practice, rules of thumb and principles can be established. Even without the aid of echometry and objective aniseikonic measurement, Rule 1 enables us to prescribe combined contact lens correction for 80% of all presbyopic patients, thus enabling them to regain comfortable binocular vision. We all know that monolateral aphakia is, unfortunately, no triumph of ophthalmological science, but rather a serious eye defect that we must correct as best we can. Conventional contact lens correction, delay in operation for cataract of the first affected eye, as well as premature operation of the second eye are, in many cases, of as little help to our patients as monolateral cataract spectacles, with occlusion of the healthy eye with normal or dark glass. In contrast, combined contact lens correction in many cases of monolateral aphakia enables the patient to regain binocular vision.

Adolescent↗