Diurnal variation of ocular hysteresis in normal subjects: relevance in clinical context
| Autor: | Ian A. Cunliffe, Sunil Shah, Mohammad Laiquzzaman, Rajan Bhojwani |
|---|---|
| Rok vydání: | 2006 |
| Předmět: |
Adult
Male medicine.medical_specialty Intraocular pressure genetic structures Context (language use) Teaching hospital Cornea Tonometry Ocular Ophthalmology medicine Humans Intraocular Pressure Morning Aged Ultrasonography Ultrasonic pachymeter business.industry Diurnal temperature variation Repeated measures design Middle Aged eye diseases Circadian Rhythm Hysteresis (economics) Optometry Female sense organs business Compliance |
| Zdroj: | Clinicalexperimental ophthalmology. 34(2) |
| ISSN: | 1442-6404 |
| Popis: | BACKGROUND This study was conducted to assess the diurnal variation in ocular hysteresis, as measured by the Ocular Response Analyser to establish a relationship between diurnal hysteresis variation and diurnal intraocular pressure (IOP) variation. METHODS Forty-two normal eyes of 21 colleagues and staff in a teaching hospital in Birmingham, UK, were recruited. The IOP and hysteresis were measured by the Ocular Response Analyser. The central corneal thickness (CCT) was measured using a hand-held ultrasonic pachymeter in the mid-pupillary axis. RESULTS The mean ocular hysteresis at 8 am was 12.7 +/- 2.3 mmHg, at 11 am was 12.2 +/- 2.0 mmHg, at 2 PM was 12.7 +/- 2.1 mmHg and at 5 PM was 12.7 +/- 1.7 mmHg; the difference between the values at any time of measurement was not statistically significant (P > 0.9, repeated measures). IOP as measured by non-contact tonometry was 18.4 +/- 2.8 mmHg, 17.9 +/- 3.3 mmHg, 16.9 +/- 3.1 mmHg and 16.8 +/- 3.2 mmHg, respectively, for the same time period; the difference between the values in the morning and afternoon was statistically significant (P < 0.0001, repeated measures). The CCT was 548.8 +/- 29.5 microm, 547.0 +/- 31.4 microm, 548.2 +/- 29.6 microm and 548.6 +/- 29.4 microm, respectively; the difference between the values was not statistically significant at any time points. Multiple regression analysis showed the relationship between IOP and hysteresis was not statistically significant (P = 0.9). CONCLUSION The ocular hysteresis reading was almost constant throughout the day, whereas the IOP readings showed highest values in the morning with a reducing trend being lowest in the afternoon. The CCT values were almost stable throughout the day. IOP appears to vary independently of a variation in hysteresis or CCT. |
| Databáze: | OpenAIRE |
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