| 1. |
- Abdelkader, Ehab, et al.
(författare)
-
Analysis of retinal structure and function in cone dystrophy with supernormal rod response
- 2020
-
Ingår i: Documenta Ophthalmologica. - : Springer Science and Business Media LLC. - 0012-4486 .- 1573-2622.
-
Tidskriftsartikel (refereegranskat)abstract
- Purpose: To report the clinical and electrophysiological features of cone dystrophy with supernormal rod response (CDSRR). Methods: Retrospective cohort study of 15 unrelated patients (nine males and six females, median age 16, range 5–47 years) diagnosed with CDSRR by clinical examination, full-field electroretinography (ERG) and genetic testing. Observations: History, ophthalmic examination including near vision, color vision and contrast sensitivity assessment, multimodal retinal imaging and ERG. Genetic testing was done for all patients using next-generation sequencing. Results: The rate of consanguinity was 86.7%. Color vision was defective in 56.3%. Near vision was defective in all patients (mean 20/160). Contrast sensitivity was affected in all patients at low contrast of 2.5%. A parafoveal ring of increased autofluorescence imaging was seen in most patients (75%). Supernormal mixed maximal response b-wave was seen bilaterally in 63% of patients (and high normal in 37%). Rod dysfunction with prolonged rod b-wave latency was detected in all. The 30-Hz flicker response was more reduced and delayed compared to the single-flash cone response. A novel homozygous missense variant c.530G>C (p.Cys177Ser) in KCNV2 was detected in one patient, the nonsense homozygous mutation c.427G>T (p.Glu143*) was found in 13 patients, and the nonsense c.159C>G (p.Tyr53*) was found in one patient. Conclusion: This is the largest cohort of CDSRR from a single ethnic background. Rod dysfunction and reduced 30-Hz flicker response were demonstrated in all patients. In contrast to previous descriptions in the literature, a supernormal combined dark-adapted rod-cone ERG was present in the majority of the patients at standard stimulus intensity. Considering the consistent genotype and the demonstration of likely pathogenic genetic variants in all the patients, we argue that the combination of delayed rod b-wave and subnormal flicker response strongly suggests the diagnosis of CDSRR.
|
|
| 2. |
|
|
| 3. |
- Burstedt, Marie S I, et al.
(författare)
-
Effects of prolonged dark adaptation in patients with retinitis pigmentosa of Bothnia type : an electrophysiological study.
- 2008
-
Ingår i: Doc Ophthalmol. - 0012-4486. ; 116:3, s. 193-205
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Bothnia dystrophy (BD) is a variant of recessive retinitis punctata albescens (RPA), caused by the missense mutation R233W in cellular retinaldehyde-binding protein (CRALBP), which is localized in the retinal pigment epithelium (RPE) and Müller cells of the retina. The purpose of this study was, by examining the electrophysiological responses of the retina, to evaluate the capacity of recovery of the whole retinal area and different cell types induced by extremely prolonged dark adaptation (DA) in BD disease and to gain further understanding of the pathogenesis of BD. Six young patients underwent bilateral full-field ERGs after 24 h of DA in one eye and standard DA in the fellow eye. The results were also compared with the effect of prolonged DA (10 h), previously studied in the same patients. After extremely prolonged DA (24 h) the rod b-wave and the mixed rod-cone a-wave responses reached normal though delayed amplitudes. An increase, up to normal level, in the oscillatory response was found. There was no obvious recovery of the cone response. We conclude that in young BD patients during extremely prolonged DA there is a significant additional capacity of recovery of rod function and also significant gain of activity in the inner retinal layer. A continuous but slow regeneration of rod photopigment seems to occur at least up to 24 h. The visual process in the RPE is retarded and CRALBP acts in this process; also, the Müller cells of the retina seem to be involved. The findings also support an extremely slow synthesis of photopigments and irreversibly disturbed cone function early in BD.
|
|
| 4. |
- Ekesten, Björn
(författare)
-
Guidelines for clinical electroretinography in the dog: 2012 update
- 2013
-
Ingår i: Documenta Ophthalmologica. - : Springer Science and Business Media LLC. - 0012-4486 .- 1573-2622. ; 127, s. 79-87
-
Tidskriftsartikel (refereegranskat)abstract
- The full-field, flash electroretinogram (ERG) is now a widely used test of canine retinal function for the clinical diagnosis of hereditary retinal dystrophies and other causes of retinal degeneration, assessment of retinal function in patients with opaque media, ruling out of generalized retinal diseases in patients with sudden loss of vision and in ophthalmological research, as well as in pharmaceutical and toxicological screening for deleterious side effects of drugs and other chemical compounds. In 2002, the first guidelines for clinical ERGs in this species adopted by the European College of Veterinary Ophthalmologists were published. This work provides an update of these guidelines.
|
|
| 5. |
- el Azazi, Mildred, et al.
(författare)
-
Background light adaptation of the retinal neuronal adaptive system. II. Dynamic effects
- 2004
-
Ingår i: Documenta Ophthalmologica. - : Springer Science and Business Media LLC. - 0012-4486 .- 1573-2622. ; 109:2, s. 201-213
-
Tidskriftsartikel (refereegranskat)abstract
- The dynamic effects of continuous exposure to light on the neuronal adaptive system of the retina, as indicated by the oscillatory response (OPs) of the electroretinogram (ERG) were studied in the albino rat. Digitally filtered OPs and the a- and b-waves of the corneal ERG were simultaneously recorded in dark adaptation, during continuous light adaptation to four levels of background light (BGL) changing in steps of two log units from 1.43 x 10(-6) cd/m2, referred to as 'low and high scotopic, low and high mesopic' levels. Exposed to 'high scotopic' BGL the total oscillatory response (SOP) significantly enhanced within the first minute, whereas the amplitudes of the a- and b-waves were unaffected. In 'low mesopic' BGL the SOP increased within the first minute, whereas the a- and b-waves significantly decreased. 'High mesopic' BGL instantaneously and profoundly reduced both the SOP and the slow potentials. The individual OPs changed in amplitudes mainly within the first minute of BGL. In general, the earlier OPs (O1 and O2) reacted more to the two 'scotopic' BGL levels, whereas the later OPs (O3 and 04) were more affected by the relatively brighter two 'mesopic' conditions. In conclusion, the rapid increase of the OPs within the first minute of 'high scotopic' and 'low mesopic' BGL exposure may represent a rudimentary light adaptational effect in the rod-dominated rat retina. These findings also suggest that the neuronal adaptive mechanism of the retina seems to be a robust system, probably attaining preservation of visual abilities in the rat on exposure to light.
|
|
| 6. |
- Frisén, Lars, 1939, et al.
(författare)
-
A primer of ophthalmic computer graphics.
- 1990
-
Ingår i: Documenta ophthalmologica. Advances in ophthalmology. - 0012-4486. ; 74:4, s. 337-50
-
Tidskriftsartikel (refereegranskat)abstract
- Computer graphics offers an unprecedented opportunity to probe new and old ideas in vision testing, without going to the expense of building dedicated equipment. However, the large variety of computer hardware is bewildering and only occasionally can commercial software tools be used. This mini review of the basic principles of computer graphics on personal computers is intended to help the newcomer to the field.
|
|
| 7. |
- Frisén, Lars, 1939
(författare)
-
Computerized perimetry: possibilities for individual adaptation and feedback.
- 1988
-
Ingår i: Documenta ophthalmologica. Advances in ophthalmology. - 0012-4486. ; 69:1, s. 3-9
-
Tidskriftsartikel (refereegranskat)abstract
- Computerized perimetry is often poorly accepted by the tested subjects, presumably because of sparse feedback and lack of adaptation to individual capacity. Several remedies are suggested, including visual response feedback, active correction of erroneous responses, various fixation prompts, and continuous adaptation to current reaction time. Intuitively intelligible result displays are also desirable. A novel format representing threshold level by symbol size may meet this need.
|
|
| 8. |
- Frisén, Lars, 1939
(författare)
-
High-pass resolution perimetry. A clinical review.
- 1993
-
Ingår i: Documenta ophthalmologica. Advances in ophthalmology. - 0012-4486. ; 83:1, s. 1-25
-
Forskningsöversikt (refereegranskat)abstract
- Review of all available reports comparing high-pass resolution perimetry (HRP) and conventional perimetry in normals and in subjects with different visual disorders reveals closely comparable aspects of sensitivity, specificity, and reliability. HRP shows important advantages concerning variability, test duration, and subject preferences. Drawbacks seem largely limited to somewhat loose renditions of visual field defects of small area and large depth. Otherwise HRP's novel format of graphic result presentation may be better suited to visual evaluation than conventional gray-scale maps with their lumping of thresholds and extensive interpolations. Several examples are provided of visual field defects due to various lesions throughout the visual system.
|
|
| 9. |
- Frisén, Lars, 1939
(författare)
-
Perimetric variability: importance of criterion level.
- 1988
-
Ingår i: Documenta ophthalmologica. Advances in ophthalmology. - 0012-4486. ; 70:4, s. 323-30
-
Tidskriftsartikel (refereegranskat)abstract
- Perimetry suffers from considerable variability of results. A new technique for estimating individual criterion levels in normal subjects exposes the important role of psychological variables. The analysis depends on features peculiar to acuity perimetry. It can be accommodated in the regular examination. The results can be used to compensate for practice effects in serial examinations and to tighten the range of normal limits. The reduction in variation between normal subjects amounted to 57 per cent.
|
|
| 10. |
|
|
