Ulla L. Nilsson

Patients with AMD and a large absolute central scotoma can be trained successfully to use eccentric viewing, as demonstrated in a scanning laser ophthalmoscope

Twenty patients with age-related macular degeneration, an absolute central scotoma and a mean visual acuity of 0.04 (20/475) were studied. A scanning laser ophthalmoscope (SLO) was used for microperimetry and determination of preferred retinal locus, often located to the left of the retinal lesion (corresponding to a location to the left of the visual field scotoma), which is considered unfavorable for reading. All 20 patients were trained to use a new and more favorable retinal locus for reading, above (or occasionally below) the retinal lesion (corresponding to a location below or above the visual field scotoma), first by reading scrolled text under simultaneous fixation monitoring and instruction in the SLO and then by reading printed text, using high magnification (mean 14.3x). For the 18 patients who learned to use eccentric viewing, reading speed with adequate magnification prior to training was 9.0+/-5.8 words/min. With training (mean 5.2 hours), it increased significantly (p<0.001) to 68.3+/-19.4 words per min. Training of eccentric reading has thus proved to be very successful.

Location and stability of a newly established eccentric retinal locus suitable for reading, achieved through training of patients with a dense central scotoma.

Six patients, median age 71 years, with a dense central scotoma in one eye and a median visual acuity of 0.06 (20/330) in the same eye, were all (100%) shown by means of fundus photography including a fixation target to preferably use an unfavorable retinal locus for fixation, i.e., within the lesion (scotoma). None of the patients was able to read novel text with the affected eye. A computer and video display system were used to determine the most suitable area above or below the visual field scotoma (below or above the retinal lesion) for reading and the magnification needed at this eccentricity. The same setup was also used for an introductory training in reading single words as well as scrolled text with the aim of establishing a preferred retinal locus (PRL) at a favorable, eccentric position, the trained retinal locus (TRL). Thereafter, the patients were provided with strong positive lenses (median power, 40 D) for reading printed text at a very short reading distance (median, 2.5 cm), first single words, above and below which help lines were printed to facilitate eccentric fixation, and finally, novel text. The total training time was 4 to 5 h. Thereafter, fundus photography showed that five of the patients (83%) used their TRL as their PRL. Reading speed was 71 words per minute (median). Our results seem to indicate that an eccentric PRL favorable for effective reading can be established through training and that a fairly low number of training sessions is required. (Optom Vis Sci 1998;75:873–878)

Rehabilitation of the visually handicapped with advanced macular degeneration

Hundred-and-twenty patients with advanced macular degeneration (senile, disciform, and hereditary forms), which could not be helped in a satisfactory way by simple magnifying aids, were studied for an average of 5 years (a minimum of 3 years), during which they had access to a full range of low vision rehabilitation measures including advanced optical aids and educational methods for training in the use of these aids and in the utilization of residual vision. The mean age of the patients was 72 years. They were all in a mental condition enabling them to understand and follow instructions. Just over half the patients were obliged to learn from the outset how to utilize peripheral retina, i.e. through eccentric viewing, high magnification low vision aids and very short reading distances, a mean of 4.4 cm, which demand specially qualified educational methods for low vision training. (A second group of 198 patients with macular degeneration was handled by the optician alone because either macular degeneration was moderate and the patients could manage with simple optical aids, or the patients were in such a bad mental condition, obvious already from the referral documents, that they were unable to use sophisticated aids in spite of the fact that they would have needed them with regard to their poor vision.)Telescopes were the most frequent aid used for distance, having a mean magnification of 4.6 X. Among the aids for reading, the most common were increased near additions and hyperocular lenses, having a mean power of 22.6 dioptres (magnification 5.7 X). Aids were also furnished for intermediate distance and for ‘spot use’. The mean number of series of visits was 2.5 and the number of training sessions (1 h) per series of visits was 3.0.Mean visual acuity improved from 0.18 to 0.64 with aids and training on the first series of visits, and reached 0.53 by the last series. The number of patients able to read TV titles increased from 6.7% to 57.5% and was 49.2% after the last series of visits. The number of individuals able to read newspaper text increased from 0.8% to 92.5%. After the last series of visits, the number was still as high as 80.0%.The results show that the presented methods for rehabilitation of patients with macular degeneration through optical aids and educational methods for training in the utilization of these aids and of residual vision are outstandingly successful. The use of the individuals vision and his situation in life often improve dramatically. In addition, costs for other forms of social aid are reduced or even eliminated.

Colour contrast sensitivity in patients with soft drusen, an early stage of ARM

The present institutional study was undertaken in order to determine whether testing of colour contrast sensitivity is valuable in detecting early functional changes in patients at initial stages of age-related maculopathy (ARM). The study included 27 patients with soft drusen as an early sign of ARM and 29 age-matched normals. The area occupied by drusen was determined using a computer program. Colour contrast sensitivity was measured with a computer graphics system. Visual acuity, central visual field (Humphrey Field Analyser) and colour vision (D-15 panel) were normal in both groups. Mean colour contrast sensitivity was significantly lower in patients with early ARM (for the protan axis: p=0.00019, for the deutan axis: p=0.000078 and for the tritan axis: p=0.000096) than in the controls. Interindividual variations were large. There was a tendency towards a bimodal distribution for all three colour axes, most evident for the tritan axis. We found a correlation of the drusen area with the protan and deutan thresholds for the fundus colour photographs r=0.5 (p<0.01) and r=0.4 (p<0.05), respectively, and with the tritan threshold for the angiograms r=0.5 (p<0.05). The findings suggest that colour contrast sensitivity may offer an additional possibility of predicting exudative ARM. Whether the patients with the highest thresholds are those who will be the first to show progression with indications of exudative ARM is not yet known. The patient group will be followed up in order to elucidate this question.

A computer and video display based system for training eccentric viewing in macular degeneration with an absolute central scotoma.

A new approach designed to establish the most suitable area for eccentric viewing and to teach and train patients with severe age-related macular degeneration (AMD) to use the eccentric viewing technique is described. Using a computer and video display based system, as well as software written specifically for this purpose, we investigated and trained ten consecutive patients with AMD. The patients were 80.1 ± 5.6 years old, on average. All of them had an absolute central scotoma. Mean visual acuity was 0.035 ± 0.016. After 30 min of testing, instruction and reading on the screen, followed by 2.6 ± 0.69 one-hour training sessions, on average, with the low vision therapist, reading newspaper and book texts with the aid of hyperoculars or aplanatic systems and a very short reading distance, the patients achieved a reading speed of 58.9 ± 19.7 words/min, significantly (p<0.001) higher than the initial speed when reading on the screen, 11.5 ± 4.5 words/min.

Significant improvements in near vision, reading speed, central visual field and related quality of life after ranibizumab treatment of wet age‐related macular degeneration

Purpose:  To investigate the effects on near visual acuity, reading speed, central visual field and related quality of life of ranibizumab treatment of wet age‐related macular degeneration (AMD).

Visual rehabilitation of patients with advanced stages of glaucoma, optic atrophy, myopia or retinitis pigmentosa.

Ninety-six patients with advanced stages of glaucoma, optic atrophy, myopia or retinitis pigmentosa (RP) who could not manage with ordinary spectacles or simple magnifying aids were taken care of at the Low Vision Clinic for rehabilitation and followed for an average of 3.6 years (the glaucoma group) up to an average of 6.0 years (the optic atrophy group). They were given high power optical aids and subjected to educational training in the proper use of these aids for best utilization of residual vision. Many of them (for optic atrophy as high a percentage as 40.7) were taught to use extra macular retina by means of eccentric viewing technique. The mean age of the oldest group, the glaucoma patients, was 69.3 years. The three other groups were about 20 to 25 years younger, on an average. (Another 35 patients) were seen for the first series of visits but could not be followed up, the main reasons being death (13 patients) and moving out of the area (9 patients).The mean power of the aids (mainly telescopes) used for distance vision was 2.1 × (RP)-5.3 x (optic atrophy). Increased near addition and hyperocular lenses were the main aids for reading and near vision, the mean power being 17.0 dioptres (glaucorna)−23.5 dioptres (RP)(4.3 × −5.9 x). Aids were also provided for intermediate distance and for “spot use”. The mean number of series of visits was 3.1 (myopia)−3.5 (glaucoma) and the average number of l h training sessions 2.2 (glaucoma)−2.5 (optic atrophy, RP) per series of visits.With aids and educational training, the mean visual acuity improved on the first series of visits from 0.31 to 0.60 for the glaucoma group, from 0.19 to 0.70 for the optic atrophy group, from 0.12 to 0.68 for the myopes and from 0.35 to 0.52 for the RP group. After the last series of visits acuity was still as good as 0.51, 0.61, 0.73 and 0.45, respectively.The number of individuals able to read newspaper text increased from 16.1% to 100.0% for the glaucoma patients, from 14.8% to 100.0% for the optic atrophy patients, from 75.0% to 100.0% for the myopes, and from 50.0% to 95.5% for the RP patients.The results show clearly that the methods used for rehabilitation of patients with glaucoma, optic atrophy, myopia or RP through optical aids and sessions of educational training are very successful, with substantial improvement of life quality.

Productivity scenarios for the Asa Forest Park

The primary focus of the SUFOR research programme was the Asa Royal Forest Park, 33 km2 in size, in which the Asa Forest Research Park 12 km2 in size, is included. A field station of the Swedish Agricultural University is located in the park, which was expropriated from its German owner in 1945 and become a Royal domain. The area is host to a number of research projects and conditions for synergistic cooperation is good. Technicians from the station assisted in sampling and data collection. Various parameters of the area are shown in Tab. 14.2. The park borders to Lake Asa, the majority of the area being found on the western side of the lake. A map of the area is shown in Fig. 13.1. The park is located 40 km north of the city of Vaxjo in the province of Smaland. Forestry in the area is traditional conifer forestry, representing the point of departure for any future changes. In the past, the original forest cover in Asa was a mixed deciduous forest dominated by lime (Tilia) and alder (Alnus), and also containing European beech (Fagus sylvatica), Scots pine (Pinus sylvestris), oak (Quercus robur) and birch (Betula). Farming on the shores of the lake started around 1200 AD and Norway spruce entered the landscape on a small scale around 1600. Mixed deciduous vegetation dominated until clearance of the land by farmers from about 1700 onwards. After 1840, Norway spruce increased markedly through colonization and through planting on land that had been abandoned after large numbers of emigrants went to America. Small crofts and farms were reforested, a process that in the province of Smaland continued as a result of urbanization from about 1930 on until the present day. From now on conifers, and Norway spruce in particular, are dominant.