Intraocular pressure during hemodialysis

In 14 patients undergoing hemodialysis, the intraocular pressure did not change significantly when measured at hourly intervals for 4 h. There was a loss in body weight because of fluid loss; also the Schirmer values decreased significantly at the conclusion of treatment. Blood osmolality decreased markedly in a linear fashion. The fluctuations of intraocular pressure during hemodialysis were likely dependent on the dynamics of dehydration and hypo-osmolality. Regulatory forces stabilized the intraocular pressure to such a degree that statistical significance in these fluctuations was not reached.     

Intraocular pressure change during hemodialysis

PURPOSE: To evaluate intraocular pressure (IOP) change through hemodialysis and examine other factors to affect IOP change in patients treated with hemodialysis. DESIGN: Prospective, observational case series. METHODS: IOP, blood pressure, and plasma colloid osmotic pressure (COP) were measured in 188 eyes of 95 patients receiving hemodialysis in Nantan General Hospital. RESULTS: IOP significantly decreased after hemodialysis (P = 0.006). Body weight, systolic and diastolic blood pressure also decreased significantly (P < 0.001). COP significantly increased (P < 0.001). Change in IOP correlated negatively with COP change (OD; r = -0.196, OS; r = -0.339) and positively with change in body weight (OD; r = -0.278, OS; r = -0.357). IOP tended to increase after hemodialysis in patients receiving hemodialysis for more than 12 years. CONCLUSIONS: IOP decrease during hemodialysis may be due to COP increase. Patients receiving hemodialysis for a long time are more likely to show IOP increase after hemodialysis.     

Intraocular pressure fluctuations during strabismus operations and the postoperative period

PURPOSE: To evaluate the intraocular pressure (IOP) variations which occur during and after strabismus surgery. METHOD: We measured the IOP in 34 eyes of 20 pediatric patients undergoing primary strabismus surgery under general anesthesia. Measurements were performed by the Tono-Pen (Mentor O&Q Inc. Norwell, MA) prior to surgery, immediately after suturing of the conjunctive, and 1 week and 4 weeks after surgery. All patients received the same local antibiotics and steroid solutions postoperatively. RESULTS: IOP decreased from baseline to the end of surgery by a mean of 8.26 +/- 1.8 mmHg and increased from baseline to 4 weeks after surgery by a mean of 3.6 +/- 1.8 mmHg. Thirty-eight percent of the eyes had an IOP of 21 mmHg or more during the postoperative period. CONCLUSION: IOP variations are prevalent during and after strabismus surgery. Careful postoperative measurements are recommended in order to identify individuals who may be prone to iatrogenically increased IOP.     

Intraocular pressure fluctuations in professional brass and woodwind musicians during common playing conditions

Background  

We investigated the effects on intraocular pressure (IOP) and blood pressure (BP) of playing brass and woodwind instruments by monitoring IOP and BP in a representative group of professional musicians under a variety of common playing conditions.     

Intraocular pressure during phacoemulsification

PURPOSE: To assess changes in intraocular pressure (IOP) during standard coaxial or bimanual microincision phacoemulsification. SETTING: Oregon Eye Center, Eugene, Oregon, USA. METHODS: Bimanual microincision phacoemulsification (microphaco) was performed in 3 cadaver eyes, and standard coaxial phacoemulsification was performed in 1 cadaver eye. A pressure transducer placed in the vitreous cavity recorded IOP at 100 readings per second. The phacoemulsification procedure was broken down into 8 stages, and mean IOP was calculated across each stage. Intraocular pressure was measured during bimanual microphaco through 2 different incision sizes and with and without the Cruise Control (Staar Surgical) connected to the aspiration line. RESULTS: Intraocular pressure exceeded 60 mm Hg (retinal perfusion pressure) during both standard coaxial and bimanual microphaco procedures. The highest IOP occurred during hydrodissection, ophthalmic viscosurgical device injection, and intraocular lens insertion. For the 8 stages of the phacoemulsification procedure delineated in this study, IOP was lower for at least 1 of the bimanual microphaco eyes compared with the standard coaxial phaco eye in 4 of the stages (hydro steps, nuclear disassembly, irritation/aspiration, anterior chamber reformation). CONCLUSION: There was no consistent difference in IOP between the bimanual microphaco eyes and the eye that had standard coaxial phacoemulsification. Bimanual microincision phacoemulsification appears to be as safe as standard small incision phacoemulsification with regard to IOP.     

Intraocular pressure during cardiopulmonary bypass.

Intraocular pressure was measured in 24 patients undergoing elective cardiopulmonary bypass surgery. There was a rapid rise when the bypass circulation began, and this was maintained for about 30 minutes. A simultaneous drop in arterial perfusion pressure and packed cell volume occurred. We suggest that marked haemodilution is responsible for this effect, through increased ocular blood flow and low colloidal osmotic pressure. The possible aetiological significance in relation to ischaemic optic neuropathy complicating cardiopulmonary bypass is discussed.     

Intraocular pressure changes during high-altitude acclimatization

Background To evaluate the relationship between hypobaric hypoxia acclimatization and intraocular pressure (IOP) during ascent, acclimatization, and descent between 2286 m and 5050 m. Methods The following acclimatization-indicative physiological parameters were compared daily with IOP changes in eight healthy climbers of the 2003 Greek Karakorum expedition in altitude stages between 500 m and 5050 m: hemoglobin oxygen saturation (PO₂), resting heart rate, blood pressure, retinal findings, and the Lake Louise score for acclimatization grading. Results IOP decreased significantly in the ascent phase (0.58 mmHg/100 m) and recovered (0.71 mmHg/100 m) during acclimatization and descent. A direct proportional correlation between decreases in PO₂ and IOP was evaluated. Arterial blood pulse and pressure increased during acclimatization, while IOP decreased. No retinal hemorrhages were observed in well-acclimatized and incompletely acclimatized climbers. Conclusions Every new active exposure to hypobaric hypoxia in the ascent phase induced a decrease in the IOP parallel to the PO₂ decrease and to the level of acclimatization. The results from our study suggest that IOP changes are related to hypoxia-induced respiratory alkalosis and acclimatization stage, which could be used as a simple mobile screening test for acclimatization level to reveal acute mountain sickness and its severe consequences.