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Aspects of the diagnosis and treatment of glaucoma
Linköping University, Department of Neuroscience and Locomotion, Ophthalmology. Linköping University, Faculty of Health Sciences.
2001 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Glaucoma is one of the most common causes of blindness in the world, and it is important that screening tests as well as treatment possibilities are improved continuously. A reliable but more rapid screening test than those already available would be of great interest. In addition, new and more effective treatment options would be most valuable. The aims of the present thesis were to evaluate the reliability of a new and rapid peripheral colour contrast sensitivity test as a tool for glaucoma screening and to gain more information on latanoprost, a recently developed prostaglandin analogue, in glaucoma treatment.

Colour contrast sensitivity was analysed with a system described by Arden and co-workers, using a computer controlled colour monitor. The test objects for the central test were letters of standard optotype subtending a visual angle of 3° . For the peripheral test, the test object was a colour contrasting annulus concentric with a fixation spot. The annulus had a radius of 12.5° in the extramacular field and a width of 1°. The colour contrast of the letter or the annulus in relation to the background could be changed, and a colour contrast threshold value could be obtained in the protan, deutan and tritan colour axes.

In a study of glaucoma patients, ocular hypertensive patients and normals, the peripheral colour contrast sensitivity test was found to distinguish the glaucoma patients from the normals. However, it was difficult to find a reliable cut-off point if the test is to be used as a screening test.

In a five-year prospective study of ocular hypertensive patients, the peripheral colour contrast sensitivity test could not clearly predict which patients would develop glaucoma and which would not, given that the Glaucoma Herrrifield Test is used as the golden standard. A change over time in the protan axis may, however, indicate glaucoma development. For a test to be used in glaucoma screening, it is necessary to know whether other common eye diseases such as diabetes and cataract affect the outcome. Therefore, the influence of diabetes and cataract on peripheral and central colour contrast sensitivity was also studied.

Diabetes type II was found to affect both peripheral and central colour contrast sensitivity, the tritan axis being the most affected one. For the tritan axis, the central colour contrast sensitivity seemed to correlate well with the degree of diabetic retinopathy, indicating the possibility of a new functional test of diabetic retinopathy.

Cataract, even moderately developed, affected both peripheral and central colour contrast sensitivity. Central colour contrast sensitivity seemed to be poorer in pseudophakic eyes than in normal eyes. Thus, both diabetes type II and moderate to severe cataract must be considered if the colour contrast sensitivity test is to be used for glaucoma screening. The choice of material for the IOL may also be of importance for postoperative central colour contrast sensitivity.

The prostaglandin analogue latanoprost effectively reduces the IOP at the original concentration of 0.005%. However, several patients need additional treatment. Therefore, the effect of pilocarpine in combination with latanoprost was studied. When pilocarpine was added to latanoprost, there was an additional reduction in the intraocular presure (IOP) (7.4%), and when latanoprost was added to pilocarpine the reduction was even more pronounced (142%). Therefore, it seems that latanoprost and pilocarpine can be combined in glaucoma treatment.

In certain eyes, an increased iris pigmentation was seen as a side-effect of latanoprost. This side-effect may be dose-dependent. Therefore, the original concentration of 0.005% was compared to a lower concentration, 0.001%. Latanoprost 0.005% was more effective than latanoprost 0.001% in reducing the IOP. However, the lower concentration was sufficiently effective to have a potential for clinical use in many patients. Latanoprost 0.005% gave an lOP reduction of 35% after four weeks of treatment, which was in agreement with earlier results. The lower concentration was, however, surprisingly effective and gave an IOP reduction of 27.7%.

Place, publisher, year, edition, pages
Linköping: Linköpings universitet , 2001. , 49 p.
Series
Linköping University Medical Dissertations, ISSN 0345-0082 ; 690
National Category
Medical and Health Sciences
Identifiers
URN: urn:nbn:se:liu:diva-28033Local ID: 12794ISBN: 91-7219-983-0 (print)OAI: oai:DiVA.org:liu-28033DiVA: diva2:248584
Public defence
2001-10-05, Berzeliussalen, Universitetssjukhuset, Linköping, 13:00 (Swedish)
Available from: 2009-10-08 Created: 2009-10-08 Last updated: 2012-08-21Bibliographically approved
List of papers
1. Peripheral colour contrast thresholds in ocular hypertension and glaucoma
Open this publication in new window or tab >>Peripheral colour contrast thresholds in ocular hypertension and glaucoma
1997 (English)In: Acta Ophthalmologica Scandinavica, ISSN 1395-3907, E-ISSN 1600-0420, Vol. 75, no 4, 376-382 p.Article in journal (Refereed) Published
Abstract [en]

Purpose: To evaluate a new test for peripheral colour contrast sensitivity as a tool for early diagnosis of glaucoma.

Patients and Methods: Peripheral colour contrast sensitivity was measured by a computer and colour monitor system developed by Arden and co-workers. The monitor displays an annulus subtending 25° at the retina. During the test, 45° of the annulus is removed in one of four quadrants. The patient is asked to identify this quadrant, first at suprathreshold levels and then as the colour contrast between the annulus and the background is varied in order to establish the threshold for identification. The tested colours were varied along the protan, deutan and tritan colour confusion axes, respectively. Thirty-three normal subjects, 22 glaucoma patients and 69 ocular hypertensive patients were examined. The ocular hypertensive patients were divided into a low risk group, a medium risk group and a high risk group.

Results: The colour contrast thresholds for the glaucoma group and the high risk ocular hypertensive group were significantly (p<0.001) higher for all three colour axes compared with the normal group. There were also significant (p < 0.05-0.001) differences for all axes between the glaucoma group on the one hand and the ocular hypertensive low risk group on the other hand. There were, however, overlaps in colour contrast thresholds between all groups.

Conclusion: Although there is a large and statistically significant difference in average colour contrast thresholds between normals and glaucoma patients, it was difficult to find an appropriate cut-off point to separate the two groups. Further studies must clarify the influence of early stages of common diseases such as cataract, diabetes and age-related maculopathy on colour contrast sensitivity.

National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-80117 (URN)10.1111/j.1600-0420.1997.tb00393.x (DOI)
Available from: 2012-08-21 Created: 2012-08-21 Last updated: 2017-12-07Bibliographically approved
2. Peripheral and central colour contrast sensitivity in diabetes
Open this publication in new window or tab >>Peripheral and central colour contrast sensitivity in diabetes
1998 (English)In: Acta Ophthalmologica Scandinavica, ISSN 1395-3907, E-ISSN 1600-0420, Vol. 76, no 5, 541-545 p.Article in journal (Refereed) Published
Abstract [en]

Purpose: To study the influence of diabetes, with or without early retinopathy, on peripheral and central colour contrast sensitivity.

Methods: The study included 32 patients with diabetes mellitus type II and 47 age-matched normals. The patients were divided into three sub-groups. 1. Diabetics with no retinopathy (on photographs or biomicroscopy). 2. Diabetics with microaneurysms only. 3. Diabetics with microaneurysms and hard exudates. Colour contrast sensitivity was measured with a computer graphics system along the protan, deutan and tritan axes.

Results: The peripheral colour contrast thresholds were significantly elevated for all axes when comparing the group with microaneurysms and exudates to normals. There were also significant differences between the group with microaneurysms and hard exudates and the two other diabetic groups, respectively, but only for the tritan axis. Diabetics with no retinopathy or with microaneurysms only did not differ significantly from normals.

The central colour contrast thresholds showed significant differences between normals and the group with microaneurysms, but only for the protan and deutan axes. There were significant differences for all three axes between normals and the group with microaneurysms and hard exudates. There were also significant differences between the group with microaneurysms and hard exudates and the two other diabetic groups, but only for the tritan axis. Diabetics with no retinopathy did not differ significantly from normals.

Conclusion: Peripheral colour contrast sensitivity was affected by low-grade diabetes type II retinopathy. This finding has to be considered if the method is to be used in screening for glaucoma. The central colour contrast sensitivity test seems to correlate to the degree of retinopathy and thereby perhaps provides a new screening method for diabetes retinopathy. Further studies are required in order to evaluate such a possibility.

National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-80118 (URN)10.1034/j.1600-0420.1998.760506.x (DOI)
Available from: 2012-08-21 Created: 2012-08-21 Last updated: 2017-12-07Bibliographically approved
3. Colour contrast sensitivity in cataract and pseudophakia
Open this publication in new window or tab >>Colour contrast sensitivity in cataract and pseudophakia
2000 (English)In: Acta Ophthalmologica Scandinavica, ISSN 1395-3907, E-ISSN 1600-0420, Vol. 78, no 5, 506-511 p.Article in journal (Refereed) Published
Abstract [en]

Purpose: To study the influence of cataract on peripheral and central colour contrast sensitivity.

Methods: Peripheral and central colour contrast sensitivity was measured with a computer graphics system along the protan, deutan and tritan axes. Included were 30 patients with cataract divided into three sub-groups: cortical cataract, nuclear sclerosis and posterior subcapsular cataract. Colour contrast was measured before and after cataract operation.

Results: There were significant differences in peripheral colour contrast thresholds comparing the preoperative and postoperative results. This difference existed even in patients (n=19) with a pre-operative visual acuity ≥0.5 (mean 0.6). The tritan axis was the one most affected by cataract. There was no significant difference between cataract sub-groups. Also, the central colour contrast sensitivity was affected by cataract. Again, the tritan axis was the most affected one. There was no significant difference between the cataract sub-groups. We also found large and significant differences in central colour contrast thresholds between normal subjects and postoperative values from the cataract group in all colour axes. The colour contrast sensitivity was poorer in pseudophakes than in normals. There was a difference between the three groups of different IOL material used (PMMA, acrylic and silicone). The difference was significant in the protan axis, the acrylic group having the best colour contrast sensitivity.

Conclusion: Peripheral colour contrast sensitivity was affected by cataract, even when only moderately developed. This finding is of importance and should be considered when the method is used to study other eye diseases e.g. glaucoma. Central colour contrast sensitivity was also affected by cataract. The pseudophakes were found to have poorer colour contrast sensitivity than normals. The material in the IOL seemed to be of importance for colour contrast.

National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-27756 (URN)10.1034/j.1600-0420.2000.078005506.x (DOI)12501 (Local ID)12501 (Archive number)12501 (OAI)
Available from: 2009-10-08 Created: 2009-10-08 Last updated: 2017-12-13Bibliographically approved
4. Colour contrast sensitivity in ocular hypertension: A five-year prospective study
Open this publication in new window or tab >>Colour contrast sensitivity in ocular hypertension: A five-year prospective study
2002 (English)In: Acta Ophthalmologica Scandinavica, ISSN 1395-3907, E-ISSN 1600-0420, Vol. 80, no 2, 155-162 p.Article in journal (Refereed) Published
Abstract [en]

Purpose:  To evaluate a peripheral colour contrast sensitivity test as a tool for early diagnosis of glaucoma in a five-year prospective study.

Patients and methods: Peripheral colour contrast sensitivity was measured with a computer graphics system developed by Arden et al. The test colours were varied along the protan, deutan and tritan colour confusion axes on a scale from 0 to 100 percentage units. Fifty-five ocular hypertensive (OH) patients examined with the colour contrast test, stereoscopic photography of the optic discs, and measurements of visual fields (Humphrey 24–2 glaucoma hemifield test (GHT)) in 1994, were re-examined after five years.

Results:  Ten patients were ‘outside normal limits’ in the GHT at follow-up. This group of 10 patients did not differ in colour contrast thresholds at the test in 1994 from the 45 who were still ‘normal’ (or ‘borderline’) at follow-up. Neither were there proportionally more patients with GHT ‘outside normal values’ for the patients with high colour contrast thresholds (> 30% units) in 1994 regarding any of the three colour axes. As judged from patient files, 27 patients had developed glaucoma during follow-up. Although there were differences between these 27 glaucoma patients and the remaining OH group at the colour contrast test in 1994, these differences did not reach statistical significance for any of the colour axes (largest difference in the tritan axis: 6.2% units, P = 0.0745). At follow-up, however, there was a significant difference in colour contrast for the protan axis between the clinical glaucoma group and the OH group (6.7% units, P = 0.0105).

Conclusion: The method used for colour contrast measurement did not reveal glaucomatous changes before conventional perimetry (Humphrey 24–2, GHT). Neither did it predict the patients who, in our clinic, subsequently developed glaucoma during a five-year period. A change over time in colour contrast in the protan axis for an OH patient may, however, indicate glaucoma development.

National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-27757 (URN)10.1034/j.1600-0420.2002.800207.x (DOI)12502 (Local ID)12502 (Archive number)12502 (OAI)
Available from: 2009-10-08 Created: 2009-10-08 Last updated: 2017-12-13Bibliographically approved
5. Interaction of PhXA41, a New Prostaglandin Analogue, With Pilocarpine: A Study on Patients With Elevated Intraocular Pressure
Open this publication in new window or tab >>Interaction of PhXA41, a New Prostaglandin Analogue, With Pilocarpine: A Study on Patients With Elevated Intraocular Pressure
1993 (English)In: Archives of ophthalmology (1960), ISSN 0003-9950, Vol. 111, no 5, 662-665 p.Article in journal (Refereed) Published
Abstract [en]

Objective.  —To evaluate the effects of PhXA41, a new prostaglandin analogue, on the intraocular pressure (IOP) in patients receiving pilocarpine treatment and the effects of pilocarpine in patients receiving PhXA41 treatment.

Design.  —Twenty patients with ocular hypertension were randomized into two parallel groups. The treatment period was 2 weeks. Ten patients in group 1 were given PhXA41 twice daily during week 1 and, in addition, pilocarpine three times daily during week 2. Ten patients in group 2 received pilocarpine three times daily during week 1 and PhXA41 twice daily in addition during week 2. PhXA41 was used in a concentration of 0.006%, and pilocarpine was given in a concentration of 2%.

Main Outcome Measures.  —In group 1, the mean IOP on day 0 was 25.1 mm Hg; on day 7,19.1 mm Hg; and on day 14,17.6 mm Hg. In group 2, the mean IOP on day 0 was 23.8 mm Hg; on day 7,20.4 mm Hg; and on day 14,17.7 mm Hg.

Results.  —PhXA41 had a clinically significant IOP-lowering effect (23.4% reduction on day 7 as compared with baseline day (P<.001). The corresponding value with pilocarpine was 14.3% (P<.001). When pilocarpine was added to PhXA41, the additional IOP reduction was 7.4% (P<.01) compared with 14.2% (P<.01) when PhXA41 was added to pilocarpine. The two groups were found to have an almost equal reduction in IOP on day 14 (group 1,29.4%; group 2, 26.6%). No serious adverse reactions were seen. Some conjunctival hyperemia in the PhXA41-treated eyes was noted on day 7, as compared with the pilocarpine-treated eyes, but there were few complaints of discomfort.

Conclusions.  —This study indicated that PhXA41 could be useful in the treatment of glaucoma, as monotherapy, or in certain cases in combination with pilocarpine.

National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-80119 (URN)8489450 (PubMedID)
Available from: 2012-08-21 Created: 2012-08-21 Last updated: 2017-12-07Bibliographically approved
6. A double masked comparison of the intraocular pressure reducing effect of latanoprost 0.005% and 0.001% administered once daily in open angle glaucoma and ocular hypertension
Open this publication in new window or tab >>A double masked comparison of the intraocular pressure reducing effect of latanoprost 0.005% and 0.001% administered once daily in open angle glaucoma and ocular hypertension
1997 (English)In: British Journal of Ophthalmology, ISSN 0007-1161, E-ISSN 1468-2079, Vol. 81, no 10, 867-870 p.Article in journal (Refereed) Published
Abstract [en]

AIM To compare the intraocular pressure (IOP) reducing effect of latanoprost 0.005% and 0.001%.

METHODS Twenty four patients with glaucoma or ocular hypertension were randomised into two groups. Twelve patients (group 1) were given latanoprost 0.005% once daily for 4 weeks and then latanoprost 0.001% once daily for the following 4 weeks. Twelve patients (group 2) were given latanoprost 0.001% once daily for 4 weeks and then latanoprost 0.005% for the following 4 weeks.

RESULTS There was a significant IOP reduction from baseline in both groups on day 28 as well as on day 56. When the results from both groups were used for calculations, the mean IOP reduction from baseline after 4 weeks of treatment with latanoprost 0.005% (day 28 or 56) was 9.6 (SD 3.3) mm Hg (35.0%). After 4 weeks of treatment with latanoprost 0.001%, the IOP reduction (day 28 or 56) was 7.6 (3.4) mm Hg (27.7%). The difference in IOP reduction between the two concentrations was 2.0 (2.3) mm Hg (p<0.001).

CONCLUSIONS Latanoprost 0.005% was more effective than latanoprost 0.001% in reducing IOP. Even the lower concentration was surprisingly effective, and potentially may be of importance for use in clinical practice. Furthermore, it is at present unknown whether the increase in iris pigmentation seen in certain patients treated with latanoprost 0.005% is dose dependent and might be less pronounced with latanoprost 0.001%. Long term studies with a larger number of patients are required in order to answer this question.

National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-80120 (URN)10.1136/bjo.81.10.867 (DOI)
Available from: 2012-08-21 Created: 2012-08-21 Last updated: 2017-12-07Bibliographically approved

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