Corneal endothelial changes seven years after phacoemulsification cataract surgery.

PURPOSE: To evaluate long-term postoperative corneal changes after phacoemulsification cataract surgery. METHODS: Twenty patients who participated in a previous study regarding corneal endothelial changes after phacoemulsification cataract surgery were examined after 7 years. The patients were divided in three groups based on their initial increase in central corneal thickness day one after the surgery: < 5% increase, 6-20% increase and ≥ 20% increase. The primary outcome measures were corneal endothelial cell loss (ECL), endothelial cell count (ECC) and endothelial morphology. RESULTS: After 7 years, a difference in cell loss between the groups was observed, except for groups 1 and 2. Endothelial cell count (ECC) differed significantly between groups 1 and 3 at 3 months. At 7 years, there was no difference in ECC between the three groups. Cell loss was found exclusively in group 1 between 3 months and 7 years. Endothelial cell morphology showed a converging pattern between 3 months and 7 years. CONCLUSION: After phacoemulsification cataract surgery, long-term ECC and morphology appear to converge towards a comparable steady state regardless of initial corneal swelling and endothelial cell loss.

Ambient air pollution and inflammation-related proteins during early childhood.

BACKGROUND AND AIM: Experimental studies show that short-term exposure to air pollution may alter cytokine concentrations. There is, however, a lack of epidemiological studies evaluating the association between long-term air pollution exposure and inflammation-related proteins in young children. Our objective was to examine whether air pollution exposure is associated with inflammation-related proteins during the first 2 years of life. METHODS: In a pooled analysis of two birth cohorts from Stockholm County (n = 158), plasma levels of 92 systemic inflammation-related proteins were measured by Olink Proseek Multiplex Inflammation panel at 6 months, 1 year and 2 years of age. Time-weighted average exposure to particles with an aerodynamic diameter of <10 µm (PM10), <2.5 µm (PM2.5), and nitrogen dioxide (NO2) at residential addresses from birth and onwards was estimated via validated dispersion models. Stratified by sex, longitudinal cross-referenced mixed effect models were applied to estimate the overall effect of preceding air pollution exposure on combined protein levels, "inflammatory proteome", over the first 2 years of life, followed by cross-sectional protein-specific bootstrapped quantile regression analysis. RESULTS: We identified significant longitudinal associations of inflammatory proteome during the first 2 years of life with preceding PM2.5 exposure, while consistent associations with PM10 and NO2 across ages were only observed among girls. Subsequent protein-specific analyses revealed significant associations of PM10 exposure with an increase in IFN-gamma and IL-12B in boys, and a decrease in IL-8 in girls at different percentiles of proteins levels, at age 6 months. Several inflammation-related proteins were also significantly associated with preceding PM10, PM2.5 and NO2 exposures, at ages 1 and 2 years, in a sex-specific manner. CONCLUSIONS: Ambient air pollution exposure influences inflammation-related protein levels already during early childhood. Our results also suggest age- and sex-specific differences in the impact of air pollution on children's inflammatory profiles.

Air pollution exposure impairs lung function in infants.

AIM: To assess associations between air pollution exposure and infant lung function. METHODS: Healthy infants from Stockholm were recruited to two cohorts (n = 99 and n = 78). Infant spirometry included plethysmography and raised volume forced expiratory flows. In pooled analyses, lung function at ~6 months of age was related to time-weighted average air pollution levels at residential addresses from birth until the lung function test. The pollutants included particulate matter with an aerodynamic diameter < 10 µm (PM10 ) or <2.5 µm and nitrogen dioxide. RESULTS: There were significant inverse relations between air pollution exposure during infancy and forced expiratory volume at 0.5 s (FEV0.5 ) as well as forced vital capacity (FVC) for all pollutants. For example, the decline was 10.1 ml (95% confidence interval 1.3-18.8) and 10.3 ml (0.5-20.1) in FEV0.5 and FVC, respectively, for an interquartile increment of 5.3 µg/m3 in PM10 . Corresponding associations for minute ventilation and functional residual capacity were 43.3 ml/min (-9.75-96.3) and 0.84 ml (-4.14-5.82). CONCLUSIONS: Air pollution exposure was associated with impaired infant lung function measures related to airway calibre and lung volume, suggesting that comparatively low levels of air pollution negatively affect lung function in early life.

Hospital-assisted home care after early discharge from a Swedish neonatal intensive care unit was safe and readmissions were rare.

AIM: It is common in Sweden to discharge infants early from a neonatal intensive care unit (NICU) and provide hospital-assisted neonatal home care (HANHC), as an alternative to hospital care, for infants with a persisting need for specialised care. This study assessed the safety of HANHC by reviewing hospital readmissions. METHODS: We retrospectively reviewed the files of all 1410 infants enrolled in HANHC at the NICU at Sachs' Children's Hospital, Stockholm, from 2002 to 2011 up until hospital readmission or their discharge from HANHC. Each readmitted infant was matched to the next HANHC infant who was not readmitted. Predictors and reasons for readmission were investigated in a retrospective nested case-control study. RESULTS: We readmitted 74 (5.2%) of the 1410 infants in HANHC. Extremely preterm infants, born at less than 28 weeks, were readmitted more frequently than other infants, with an odds ratio of 6.07 (range 2.06-17.8). The most common symptoms were respiratory symptoms (55%), and viral respiratory tract infections were the most common reason (28%) for readmission. CONCLUSION: HANHC was safe for the vast majority of infants (94.8%). Extremely preterm birth was identified as a predictor for hospital readmission. Further studies investigating the safety of HANHC in other settings would be valuable.

Changes in intraocular pressure during the first 24 h after transscleral cyclophotocoagulation.

AIMS: To estimate the changes in intraocular pressure (IOP) during the first 24 h after transscleral cyclophotocoagulation (TCP). METHODS: A prospective single-centre study, where patients with glaucoma destined for treatment with TCP were asked for participation. The IOP was measured prior to TCP and at 1, 2, 4, 6 and 24 h post-TCP. An IOP spike was defined as an elevation of IOP of ≥5 mmHg compared with baseline. The visual acuity (VA) was examined at baseline and after 24 h. RESULTS: The mean IOP prior to TCP in 58 eyes of 58 patients was 26.2 (±8.9 SD) mmHg. Twenty-three eyes (40%) experienced an IOP spike at some examination timepoint during the first 24 h. The mean value of the IOP spike was 12.1 (±6.9) mmHg. Fifty-six per cent of the eyes with pseudoexfoliation glaucoma (PEXG) experienced an IOP spike, and 16% had an IOP spike ≥20 mmHg. The IOP was significantly reduced at the 24 h examination by 8.1 (±7.8) mmHg (n = 58). The VA 24 h after TCP was unchanged compared with baseline. CONCLUSION: Clinically significant IOP spikes were common in the first 24 h post-TCP. Almost one in five eyes had an increase of 10 mmHg and in almost one in 10 eyes, the IOP increase was 20 mmHg or higher. Eyes with PEXG had a higher occurrence of IOP spikes and displayed a greater magnitude of IOP elevation. Prophylactic post-operative IOP-lowering medication should be considered to prevent further glaucoma damage.

Lung function in young adulthood in relation to moderate-to-late preterm birth.

Background: Moderate-to-late preterm birth (32 to <37 weeks of gestation) has been associated with impaired lung function in adolescence, but data in adulthood and physiological phenotyping beyond spirometry are scarce. We aimed to investigate lung function development from adolescence into young adulthood and to provide physiological phenotyping in individuals born moderate-to-late preterm. Methods: Lung function data from individuals born moderate-to-late preterm (n=110) and term (37 to <42 weeks of gestation, n=1895) in the Swedish birth cohort BAMSE were used for analysis and included dynamic spirometry, fractional exhaled nitric oxide and multiple breath nitrogen wash-out. Data from 16- and 24-year follow-ups were analysed using regression models stratified on sex and adjusted for smoking. Data-driven latent class analysis was used to phenotype moderate-to-late preterm individuals at 24 years, and groups were related to background factors. Results: Males born moderate-to-late preterm had lower forced expiratory volume in 1 s (FEV1) at 24 years of age (-0.28 z-score, p=0.045), compared to males born term. In females, no difference was seen at 24 years, partly explained by a significant catch up in FEV1 between 16 and 24 years (0.18 z-score, p=0.01). Lung function phenotypes described as "asthma-like", "dysanapsis-like" and "preterm reference" were identified within the preterm group. Maternal overweight in early pregnancy was associated with "asthma-like" group membership (OR 3.59, p=0.02). Conclusion: Our results show impaired FEV1 at peak lung function in males born moderate-to-late preterm, while females born moderate-to-late preterm had significant catch up between the ages of 16 and 24 years. Several phenotypes of lung function impairment exist in individuals born moderate-to-late preterm.

Hallmark Molecular and Pathological Features of POLG Disease are Recapitulated in Cerebral Organoids.

In this research, a 3D brain organoid model is developed to study POLG-related encephalopathy, a mitochondrial disease stemming from POLG mutations. Induced pluripotent stem cells (iPSCs) derived from patients with these mutations is utilized to generate cortical organoids, which exhibited typical features of the diseases with POLG mutations, such as altered morphology, neuronal loss, and mitochondiral DNA (mtDNA) depletion. Significant dysregulation is also identified in pathways crucial for neuronal development and function, alongside upregulated NOTCH and JAK-STAT signaling pathways. Metformin treatment ameliorated many of these abnormalities, except for the persistent affliction of inhibitory dopamine-glutamate (DA GLU) neurons. This novel model effectively mirrors both the molecular and pathological attributes of diseases with POLG mutations, providing a valuable tool for mechanistic understanding and therapeutic screening for POLG-related disorders and other conditions characterized by compromised neuronal mtDNA maintenance and complex I deficiency.

The NAD+ Precursor Nicotinamide Riboside Rescues Mitochondrial Defects and Neuronal Loss in iPSC derived Cortical Organoid of Alpers' Disease.

Alpers' syndrome is an early-onset neurodegenerative disorder usually caused by biallelic pathogenic variants in the gene encoding the catalytic subunit of polymerase-gamma (POLG), which is essential for mitochondrial DNA (mtDNA) replication. The disease is progressive, incurable, and inevitably it leads to death from drug-resistant status epilepticus. The neurological features of Alpers' syndrome are intractable epilepsy and developmental regression, with no effective treatment; the underlying mechanisms are still elusive, partially due to lack of good experimental models. Here, we generated the patient derived induced pluripotent stem cells (iPSCs) from one Alpers' patient carrying the compound heterozygous mutations of A467T (c.1399G>A) and P589L (c.1766C>T), and further differentiated them into cortical organoids and neural stem cells (NSCs) for mechanistic studies of neural dysfunction in Alpers' syndrome. Patient cortical organoids exhibited a phenotype that faithfully replicated the molecular changes found in patient postmortem brain tissue, as evidenced by cortical neuronal loss and depletion of mtDNA and complex I (CI). Patient NSCs showed mitochondrial dysfunction leading to ROS overproduction and downregulation of the NADH pathway. More importantly, the NAD+ precursor nicotinamide riboside (NR) significantly ameliorated mitochondrial defects in patient brain organoids. Our findings demonstrate that the iPSC model and brain organoids are good in vitro models of Alpers' disease; this first-in-its-kind stem cell platform for Alpers' syndrome enables therapeutic exploration and has identified NR as a viable drug candidate for Alpers' disease and, potentially, other mitochondrial diseases with similar causes.

Agreement between spirometry and impulse oscillometry for lung function assessment in 6-year-old children born extremely preterm and at term.

BACKGROUND: Extremely preterm birth is a risk factor for reduced lung function later in life, and clinical follow-up from early childhood is recommended. Dynamic spirometry is the most widely used method to assess airway obstruction, but impulse oscillometry (IOS) may be an alternative method that is easier to perform in young children. The feasibility and agreement between spirometry and IOS outcome variables has not been investigated in children born extremely preterm. AIM: To determine the feasibility of and correlation between spirometry and IOS in pre-school children born extremely preterm. METHODS: Spirometry and IOS were performed in 6-year-old children born extremely preterm (n = 88) and age-matched term controls (n = 84) in Stockholm, Sweden. Correlations between spirometry and IOS outcome variables were analyzed using Pearson's partial correlation, adjusting for height. RESULTS: Success rate for spirometry (60%) was lower than for IOS (93%) but did not differ significantly between the preterm and term groups (56% and 64% for spirometry, P = .25; and 92% and 94% for IOS, P = .61). Correlations between spirometry and IOS outcomes were at best moderate (Spearman's r = -0.31 to -0.56). Normal IOS identified 69% to 90% of those with normal spirometry. A negative predictive value of 90% was found for R5-R20 versus FEV0.75 /FVC, suggesting that IOS may be used to exclude obstructive airway disease as measured by spirometry. CONCLUSION: IOS is a more feasible method than spirometry to assess lung function in young children irrespective of gestational age at birth and could be considered an alternative in children who cannot perform spirometry.

Efficacy and safety of transscleral cyclophotocoagulation in Swedish glaucoma patients.

PURPOSE: To retrospectively evaluate the efficacy and safety of all transscleral cyclophotocoagulation (TCP) treatments performed during a 5-year period. METHODS: Medical records of all patients, who had undergone TCP treatment between 2010 and 2014 at Umeå University Hospital, Sweden, were evaluated. Clinical data including intraocular pressure (IOP), visual acuity (VA), number of topical glaucoma medications, use of oral acetazolamide, retreatments and complications during a 2-year follow-up were registered. Global success was defined as IOP 6-18 mmHg with or without glaucoma medication. RESULTS: Three hundred patients underwent TCP during the time period. Mean IOP at baseline was 29.3 ± 11.0 (mean ± standard deviation) mmHg (n = 297) with a mean reduction of 11.5 (±12.0) mmHg at 1 year (n = 258; p < 0.001) and 12.6 (±12.0) mmHg at 2-year follow-up (n = 245; p < 0.001). Global success at 2 years was 64%, achieved by a mean of 1.2 treatments (n = 257). The number of topical glaucoma medications at baseline was 3.1 (±1.0; n = 296) and was reduced by 0.9 (±1.0) medications at 2 years (n = 244; p < 0.001). Use of oral acetazolamide decreased from 30% (n = 90) at baseline to 5.3% (n = 13) at 2 years. In eyes with Snellen VA ≥ 0.1, the mean VA at baseline was 0.55 (±0.3) logarithm of the minimum angle of resolution (logMAR; n = 132) and 1.1 (±0.9) logMAR (n = 76) at 2 years (p < 0.001). No cases of phthisis bulbi were found. CONCLUSION: This study displays a substantial and long-term reduction of IOP following TCP with a decrease in topical and oral glaucoma medications. The treatment appears to be safe but the decrease in VA during follow-up is a concern that needs further evaluation.

Separate and additive mydriatic effects of lidocaine hydrochloride, phenylephrine, and cyclopentolate after intracameral injection.

PURPOSE: To assess the separate mydriatic effect of lidocaine hydrochloride (Xylocaine), cyclopentolate, and phenylephrine after intracameral injection and evaluate whether intracameral Xylocaine and phenylephrine without cyclopentolate provide sufficient pupil dilation for cataract surgery. SETTING: Department of Clinical Science/Ophthalmology, Umeå University Hospital, Umeå, Sweden. METHODS: This prospective randomized double-masked study included 56 patients with age-related cataract scheduled for unilateral phacoemulsification. In 16 patients, Xylocaine 1%, phenylephrine 1.5%, and cyclopentolate 0.1% were injected one after the other. Phenylephrine and cyclopentolate were randomized to switch in order, creating 2 study groups. An additional 40 patients were randomized to receive intracameral Xylocaine 1%, phenylephrine 1.5%, and cyclopentolate 0.1% or intracameral Xylocaine 1% and phenylephrine 1.5% only. RESULTS: Xylocaine alone caused significant pupil dilation (mean 4.9 +/- 0.6 mm). In the group in which cyclopentolate was injected next, the pupil size increased 1.3 +/- 0.6 mm (P<.001). When phenylephrine was added, the pupil increased an additional 0.7 +/- 0.4 mm (P = .003). In the second group, in which phenylephrine was the second injection, the pupil size increased 2.1 +/- 0.5 mm (P<.001). When cyclopentolate was added, no significant change in size occurred. No statistically significant differences in pupil size were observed between the 40 patients who were given intracameral mydriatics with or without cyclopentolate. CONCLUSIONS: Xylocaine plus phenylephrine injected intracamerally gave adequate intraoperative pupil dilation in routine phacoemulsification surgery. Cyclopentolate administrated intracamerally had no immediate additive mydriatic effect to intracameral Xylocaine combined with phenylephrine.

Optical coherence tomography evaluation of macular edema after phacoemulsification surgery with intracameral mydriatics.

PURPOSE: To quantify the macular edema induced by intracameral mydriatics in phacoemulsification surgery. SETTING: University hospital eye clinic, Umeå, Sweden. METHODS: In a randomized study of 22 patients, 11 patients were given 150 muL of a mixture of phenylephrine 1.5% and lidocaine 1% intracamerally for mydriasis and anesthesia. In a control group (n = 11), conventional topical mydriatics and intracameral lidocaine were given. Multiple preoperative, intraoperative, and postoperative variables were recorded. RESULTS: There were no differences in macular edema between the 2 treatments. A correlation was seen between macular edema and impaired visual acuity 1 week postoperatively. On the first postoperative day, a similar correlation was seen between corneal edema and the degree of visual improvement. CONCLUSIONS: Intracameral lidocaine and phenylephrine for mydriasis and anesthesia did not induce more significant macular edema than the standard regimen of topical mydriatics plus intracameral lidocaine. Macular edema limited visual improvement 1 week after phacoemulsification, while corneal edema appeared to have a larger effect immediately after surgery.

Postoperative corneal swelling correlates strongly to corneal endothelial cell loss after phacoemulsification cataract surgery.

PURPOSE: To evaluate postoperative corneal swelling as a predictor of corneal endothelial cell loss after phacoemulsification cataract surgery. DESIGN: Prospective observational case series. METHODS: Thirty patients planned for routine phacoemulsification cataract surgery were included. Ultrasonic pachymetry and specular microscope endothelial photography of the central and nasal portions of the cornea and Orbscan II slit-scan tomography were performed preoperatively and the day after surgery. The 30 patients were selected from 41 patients based on their increase in central corneal thickness: the first 10 cases with a <5% increase, the first 10 with a 6% to 20% increase, and the first 10 with a > or =20% increase. The same measurements were repeated after 1, 2, and 3 months. The primary outcome measures were corneal endothelial cell loss and increase in pachymetry. Several other parameters were also registered, including age, degree of cataract, visual acuity, phacoemulsification time and energy, total operation time, and the amount of infusion fluid used. RESULTS: The central corneal swelling at postoperative day 1 was strongly correlated with the central corneal endothelial cell loss at 3 months (R(2) = 0.785, P < .001). CONCLUSIONS: In this series, with large variations in the corneal swelling at the first postoperative day, the degree of permanent corneal endothelial damage was reflected in the degree of early postoperative corneal swelling. Measuring the difference in pachymetry at postoperative day 1 is a useful way to assess the effects on the corneal endothelium exerted by the phacoemulsification procedure.

Transient corneal edema after phacoemulsification: comparison of 3 viscoelastic regimens.

PURPOSE: To evaluate the effect of different viscoelastic substances on the grade and time course of postoperative corneal edema. SETTING: Department of Clinical Sciences/Ophthalmology, Umeå University Hospital, Umeå, Sweden. METHODS: This study comprised 62 patients with otherwise healthy eyes who had routine phacoemulsification and intraocular lens (IOL) implantation. Patients were divided into 3 groups. Group 1 was given Healon GV (sodium hyaluronate 1.4%) at phacoemulsification and IOL implantation. Group 2 was given Viscoat (sodium hyaluronate 3.0%-chondroitin sulfate 4.0%) at phacoemulsification and Healon GV at IOL implantation. Group 3 was given Viscoat at phacoemulsification and Provisc (sodium hyaluronate 1.0%) at lens implantation. The central corneal thickness was measured with ultrasonic pachymetry before surgery and 5 and 24 hours, 1 week, and 1 month after surgery. RESULTS: The mean increase in corneal thickness was significantly greater in Group 1 than in the other 2 groups 5 and 24 hours and 1 week after surgery. CONCLUSIONS: The transient postoperative increase in central corneal thickness was greater in patients receiving Healon GV during phacoemulsification than in patients receiving Viscoat. The use of Provisc or Healon GV for IOL implantation did not affect the postoperative corneal thickness when Viscoat was used for phacoemulsification. The time course of the edema may be explained by a difference between the 2 agents in endothelial protection from ultrasonic, mechanical, or irrigation trauma.

Intracameral mydriatics in phacoemulsification cataract surgery.

PURPOSE: To evaluate intracameral injection of mydriatics in phacoemulsification cataract surgery and compare the results with those of conventional topical mydriatics. SETTING: Department of Clinical Science/Ophthalmology, Umeå University Hospital, Umeå, Sweden. METHODS: This prospective randomized double-blind study included 60 patients who were given topical (topical group) or intracameral (intracameral group) mydriatics. The topical mydriatics comprised 3 drops of cyclopentolate 1% and phenylephrine 10% given 15 minutes apart and 150 microL intracameral lidocaine hydrochloride 1% (Xylocaine) and the intracameral mydriatics, placebo eyedrops and 150 microL intracameral cyclopentolate 0.1%, phenylephrine 1.5%, and Xylocaine 1%. The pupil size was recorded preoperatively, throughout surgery, and 1 day and 1 month postoperatively. Preoperative and postoperative corneal endothelial morphology, corneal thickness, intraocular pressure, visual acuity, aqueous cells and flare, phacoemulsification energy, duration of surgery, pulse, blood pressure, and intraoperative sensation of pain and glare were also recorded. RESULTS: With intracameral mydriatics, mydriasis reached 95% +/- 3% (SD) of its final value within 20 seconds. In the intracameral group, the pupils were smaller than in the topical group (mean 6.7 +/- 1.0 mm versus 7.7 +/- 1.0 mm, P<.001) but did not contract intraoperatively. The pupils in the topical group tended to contract, and the difference between groups was significant (P =.0020). The intracameral group reported less glare during the procedure (P<.001). There was no difference in endothelial cell loss, inflammatory reaction, postoperative corneal swelling, or surgical performance between the groups. CONCLUSIONS: Intracameral mydriatics were a rapid, effective, and safe alternative to topical mydriatics in phacoemulsification. Their use can simplify preoperative routines and in certain high-risk groups, may reduce the risk for cardiovascular side effects.

Intracameral mydriatics in phacoemulsification cataract surgery -- a 6-year follow-up.

PURPOSE: To evaluate the long-term safety of intracameral mydriatics (ICM) in phacoemulsification cataract surgery compared with conventional topical mydriatics (TM). METHODS: A total of 45 patients were examined 6 years after phacoemulsification cataract surgery. The patients had previously participated in a prospective randomized double-blind study including 60 patients, operated with either ICM or TM. The follow-up included best-corrected visual acuity (BCVA), intraocular pressure (IOP), grade of posterior capsule opacification (PCO), YAG laser capsulotomy rate, pupil size, corneal thickness and endothelial morphology. RESULTS: No differences in postoperative BCVA, IOP, pupil size, PCO or YAG rate were observed between the groups. Endothelial cell loss, endothelial morphology and corneal thickness were also equivalent. CONCLUSIONS: Intracameral mydriatics is a safe alternative to topical mydriatics in phacoemulsification cataract surgery with no long-term disadvantages at 6-year follow-up.

Intracameral acetylcholine effectively contracts pupils after dilatation with intracameral mydriatics.

PURPOSE: To determine whether intracameral acetylcholine can contract pupils dilated with intracameral mydriatics in phacoemulsification cataract surgery. METHODS: A total of 60 patients were included in this prospective randomized masked study performed at Örnsköldsviks Hospital Eye Clinic. The patients were randomized and were given either topical placebo and an intracameral mydriatic solution (ICM) (cyclopentolate 0.1%, phenylephrine 1.5% and xylocaine 1%) (n = 30) or topical mydriatics (TM) (cyclopentolate 0.85% and phenylephrine 1.5%) and xylocaine 1% intracamerally (n = 30) at the start of surgery. After intraocular lens (IOL) implantation, 0.15 ml 1% acetylcholine was given intracamerally in all cases. The pupil size was registered preoperatively, 45 seconds after intracameral injection, after ophthalmic viscosurgical device (OVD) evacuation, 30 seconds after acetylcholine injection, 2 min after acetylcholine injection and the day after surgery. RESULTS: The pupil contraction and pupil size after acetylcholine injection showed no significant differences at 30 seconds (contraction 1.0 ± 0.4 in ICM group versus 0.9 ± 0.4 in TM group; p = 0.75; size 4.8 ± 1.1 in the ICM group versus 5.2 ± 1.1 in the TM group; p = 0.24) or at 2 min (contraction 1.5 ± 0.6 in the ICM group versus 1.4 ± 0.6 in the TM group; p = 0.63; size 4.3 ± 0.9 in the ICM group versus 4.7 ± 1.0 in the TM group; p = 0.13). No difference in baseline pupil size after ophthalmic viscosurgical device (OVD) evacuation was seen between the two groups (5.8 ± 0.9 in the ICM group versus 6.1 ± 1.2 in the TM group; p = 0.28). CONCLUSION: We here show that intracameral acetylcholine contracts pupils as effectively after dilatation with intracameral mydriatics as after dilatation with topical mydriatics. Cataract surgeons can feel comfortable and safe when using intracameral mydriatics, even if pupil contraction with acetylcholine should be required.

Stimulation of adrenergic ß-receptors enhances mydriasis in a porcine eye model.

PURPOSE: To compare the mydriatic effect of intracamerally injected isoprenaline plus phenylephrine to phenylephrine alone and to epinephrine in a porcine eye model, aiming to eventually find the best combination of adrenergic substances for surgical mydriasis in humans. METHODS: In this study, we used 89 intact eyes from newly slaughtered pigs, pretreated with 2.0 mg of intracameral acetylcholine. After waiting 60 seconds for miosis to develop, 0.15 ml 0.3% isoprenaline and 0.15 ml 3.0% phenylephrine were injected sequentially with a 90-second interval in 21 eyes. In another 22 eyes, the same substances were given in the reverse order. In 20 eyes, 0.15 ml of 0.025% epinephrine was injected, and as a negative control 0.15 ml of balanced salt solution was injected in 26 eyes. The pupils were filmed during the treatments, and the mean pupil diameters were measured every 15 seconds from the video recordings. RESULTS: Phenylephrine injected after isoprenaline had a larger mydriatic effect than epinephrine (p < 0.01). Without isoprenaline pretreatment, the mydriatic effect of phenylephrine was significantly smaller than that of epinephrine (p < 0.05). Isoprenaline also exhibited a small mydriatic effect of its own. CONCLUSIONS: The ß-receptor stimulator isoprenaline enhances the mydriatic effect of intracameral phenylephrine, indicating a role for the ß-receptor in the mydriatic response. Mydriasis mediated by ß-receptors may explain why nonspecific adrenergic stimulators such as epinine and epinephrine can have larger mydriatic effects than the specific α(1)-receptor stimulator phenylephrine.

Mydriatic response to different concentrations of intracameral phenylephrine in humans.

PURPOSE: To assess the mydriatic response to concentrations of intracamerally injected phenylephrine from 0.15 mg/mL to 30.00 mg/mL (0.015% to 3.000%) in human eyes. SETTING: Department of Clinical Science/Ophthalmology, Umeå University Hospital, Umeå, Sweden. DESIGN: Comparative case series. METHODS: This prospective randomized double-masked study comprised patients scheduled for phacoemulsification cataract surgery. At the beginning of the procedure, patients received an intracameral injection of 0.15 mL of phenylephrine 0.15, 0.5, 1.5, 5.0, 15.0, or 30.0 mg/mL. To assess the mydriatic response, the pupil size was registered over 60 seconds using digital video recording. Then, the surgery was performed in the standard manner. RESULTS: The study evaluated 42 patients. The mydriatic response was almost identical at the 4 lower phenylephrine concentrations (0.15 to 5.00 mg/mL; 0.015% to 0.500%), with final pupil sizes of approximately 4.3 mm. The 2 higher concentrations gave significantly larger pupils as follows: mean 5.80 mm ± 0.79 (SD) for 15.0 mg/mL (1.5%) and 6.65 mm ± 0.57 for 30.0 mg/mL (3.0%). CONCLUSIONS: Results show that phenylephrine injected intracamerally does not have a linear mydriatic dose-response relationship in humans. At very high concentrations, phenylephrine may bind to and stimulate receptors other than the α(1)-receptor, explaining this phenomenon.