Instillation Of Tropicamide Research Articles

Short-term anatomic response of the choroid to tropicamide in myopic patients.

We aimed to investigate how tropicamide alters subfoveal choroidal thickness (SFChT) and choriocapillaris flow density (CD) and determine the predictive factors of choroid thickness and vascular density in myopic eyes. This retrospective study was conducted from September 2018 to March 2019. SFChT was measured with enhanced depth spectrum-domain optical coherence tomography. The choriocapillaris was imaged using optical coherence tomography angiograms. Ocular parameters were measured thirty minutes before and after 1% tropicamide instillation. Twenty-five eyes of 15 patients (mean age 38.12 ± 6.35 years old and refractive error-8.57 ± 3.37 D) met the study criteria. The baseline linear regression model showed an association of thinner choroid with older age (P = .027) and high myopic patients (P = .001). Tropicamide substantially increased SFChT (P = .001), but had no significant influence on CD (P = .526). Moreover, SFChT variation after tropicamide instillation positively correlated with diopter changes in spherical equivalent (P = .005) and percentage changes in CD (P = .046). In myopic eyes, choroidal layer thickened substantially in response to tropicamide. The increase of SFChT only correlates with variations in spherical equivalent and CD. Short-term tropicamide installation altered both choroid thickness and choroid microvasculature, which implies an interplay among choroidal volume, perfusion, and ciliary muscle tone.

The effect of topical tropicamide and phenylephrine on macular and peripapillary microvasculature: an optical coherence tomography angiography study.

To evaluate the effect of topical tropicamide 1% and phenylephrine 2.5% instillation on macular and peripapillary microvasculature measurements with optical coherence tomography angiography (OCTA). Forty eyes of 40 consecutive healthy adults with no known systemic or ocular disease were recruited for this prospective consecutive case study. After complete ophthalmological examination, all patients underwent OCTA measurements (OptoVue Inc, Freemont, CA, USA) to assess foveal avascular zone (FAZ) area, FAZ perimeter, acircularity index of FAZ, foveal density, vessel density of superficial and deep capillary plexus and peripapillary capillary plexus. 6 × 6mm macular and 4.5 × 4.5mm peripapillary OCTA images were undertaken before and 30 min after instillation of tropicamide (20 eyes) or phenylephrine (20 eyes) instillation to the right eye, and these were compared to each other and to fellow control eye. 15 male and 25 female patients with a mean age of 43.3 (18-60) years were recruited for the study. Superficial, deep and peripapillary capillary plexus measurements of tropicamide 1% and phenylephrine 2.5% instilled right eyes and left control eyes were similar before and 30 min after instillation (P > 0.05 for all). FAZ assessment tool variables were also similar before and after instillation (P > 0.05 for all) for both eyes. Topical pupillary dilatation with tropicamide 1% and phenylephrine 2.5% did not affect macular and peripapillary OCTA measurements. Follow-up OCTA images in retina and glaucoma patients can be captured with a dilated or undilated pupil which seems not to be affected by tropicamide or phenylephrine.

Effect of Topical Proparacaine 0.5% on Tropicamide- Induced Mydriasis

Purpose: The topical anesthetic proparacaine (0.5%) is recommended to enhance the rate and magnitude of pupillary dilatation if it is instilled before mydriatic tropicamide. However there is scarcity of data supporting this. Therefore we conducted a study to analyze if preinstillation of topical proparacaine (0.5%) can potentiate the mydriatic efficacy of 0.8% tropicamide.
 Methods: The patients were divided into two groups for pupillary dilatation. The study group was given a drop 0.5% proparacaine before instilling one drop of tropicamide while the control group was given the tropicamide alone. The pupillary size was measured and recorded before the instillation of tropicamide at 0 min, 15 min, 30 min. The end point was taken as 6 mm pupillary size (clinically effective diameter).
 Results: There was a statistically significant difference in rate of pupillary diameter between the control and the study group. The rate of pupillary dilatation at 15min and 30 min was statistically significantly different between the control and study group.
 Conclusion: The study concluded that prior instillation of topical proparacaine produced a statistically significant difference in the rate of pupillary dilatation at 30 mins. Therefore, we suggest the use of a topical anesthetic before tropicamide induced mydriasis.

PB2313 OCULAR MANIFESTATIONS OF SICKLE CELL DISEASE: A SINGLE CENTRE STUDY

Background:Sickle cell disease (SCD) is an inherited haemolytic disorder that affects virtually all body systems including the eye. Ocular complications of SCD could have dire consequences if not detected early.Aims:We aimed at determining the prevalence of ocular complications of SCD in our patients.Methods:This study was carried out on patients attending both the adult and Paediatric Sickle cell clinic at Chukwuemeka Odumegwu Ojukwu teaching Hospital, Akwa, Anambra State, Nigeria, over a 6 month period. A structured questionnaire was administered to consenting patients to determine their sociodemographic variables and other characteristics. Visual acuity was determined with multiple optotype Snellen's chart at 6 metres in natural daylight. Using pen‐torch, the face, external eye examination, anterior segment examination and pupillary reaction to light were assessed. Magnified anterior segment examination was performed with slit‐lamp biomicroscope. All subjects underwent dilated fundoscopy (after instillation of tropicamide 0.5% eye drop) using Welch Allyn indirect ophthalmoscope.Results were analysed using SPSS version 22.0 Inc Chicago Illinois and represented in tables. Statistically significant P value was set at < 0.05Results:A total of 28 patients with age range of 6‐42 years were seen. 17(60.7%) were males, while 11(39.3%) were females. 8(28.6%) had at least one ocular anomaly comprising of refractory errors 3(10.8%), sickle cell retinopathy 4(14.3%) and glaucoma 2(7.1%). Only 2(7.1%) routinely visit eye clinic. SCD retinopathy was found to increase with age (P value = 0.005)Summary/Conclusion:SCD retinopathy was found more in the older age group despite the small sample size at a prevalence rate of 14.3%. Early initiation of routine ocular examination for SCD patients will be beneficial to avert these complications. More efforts should be made at educating the patients. Larger studies will be required to determine the actual prevalence of ocular anomaly in SCD patients in Anambra State.

Corneal Biomechanics in Patients with Glaucoma: The Effect of Pupillary Dilatation

\n Aim: In this study, we aimed to evaluate the effect of pupillary dilatation on intraocular pressure values and corneal biomechanical properties using Ocular response analyzer in eyes with primer open angle glaucoma.\n\n Patients and Methods: Goldmann correlated intraocular pressure, corneal corrected intraocular pressure, corneal hysteresis and corneal resistance factor were all respectively evaluated in 28 eyes of 15 patients with primary open angle glaucoma before and 30 minutes after tropicamide 0.5% instillation.\n\n Results: Their mean age was 57.7±13.2 years (range 45–65 years). The mean corneal hysteresis, corneal resistance factor, Goldmann correlated intraocular pressure and corneal corrected intraocular pressure measurements of the eyes were 9.5±2.2 mmHg, 10.1±2.1 mmHg, 16.2±2.8 mmHg, 17.2±3.6 mmHg before tropicamide instillation, and 9.7±2.2 mmHg, 10.1±2.0 mmHg, 16.9±3.5 mmHg, 18.2±4.0 mmHg after tropicamide instillation, respectively. There was statistically significant difference between pre- and post-tropicamide instillation for Goldmann correlated intraocular pressure and corneal corrected intraocular pressure (p=0.043, p=0.015, respectively; paired t-test) while no statistically significant difference was found for corneal hysteresis and corneal resistance factor (p=0.057 p=0.702, respectively; paired t-test ). \n\n Conclusion: Pupillary dilatation with 0.5% tropicamide seems to have a decreasing effect on on intraocular pressure while no effect was noted for corneal biomechanical properties in primer open angle glaucoma patients.\n\n \n\n \n

Anterior Segment Biometry with Phenylephrine and Tropicamide during Accommodation Imaged with Ultralong Scan Depth Optical Coherence Tomography.

Purpose To investigate the influence of phenylephrine and tropicamide on anterior segment biometry with ultralong scan depth optical coherence tomography (UL-OCT) during accommodation. Methods In this study, 20 left eyes of healthy volunteers with a mean ± standard deviation age of 31.05 ± 5.84 years and a mean refraction of −1.16 ± 1.11 diopters (range 0∼−3.0 D) were imaged using UL-OCT after instillation of artificial tears, phenylephrine, and tropicamide in three follow-up trials, respectively. At each follow-up trial, two repeated measurements were performed at states of relax and 5D accommodative stimulation. The dimensional parameters included central corneal thickness (CCT), anterior chamber depth (ACD), pupil diameter (PD), lens thickness (LT), and horizontal radii of the lens anterior and posterior surface curvatures (LAC and LPC). Results Tropicamide led to larger pupil, deeper ACD, thinner LT, and flatter crystalline lens surface (P < 0.05). Phenylephrine induced an increase in PD (P < 0.05), while no significant changes were seen in ACD, LT, LAC, and LPC (P > 0.05). CCT did not change after both phenylephrine and tropicamide instillation in this study (P > 0.05). Tropicamide induced the loss of accommodation and phenylephrine achieved pupil dilation without affecting the accommodation. PD, ACD decreased, LT increased significantly and the anterior and posterior surface of the lens in a 6.294 mm of diameter optical zone became steeper during accommodation after administration of phenylephrine (P < 0.05). Conclusion The anterior segment physiology changed after tropicamide instillation. Besides, tropicamide induced the loss of accommodation and phenylephrine preserved the accommodation with a larger pupil. And, the anterior and posterior surface of lens in a 6.294 mm of diameter optical zone became steeper during the accommodation.

Structure versus function: correlation between outer retinal and choroidal thicknesses measured by swept-source OCT with multifocal electroretinography and visual acuity

BackgroundTo correlate retina-choroidal anatomy as assessed via swept-source OCT (SS-OCT) with retinal function as determined by best-corrected visual acuity (BCVA) and multifocal electroretinogram (mfERG).MethodsThirty-three eyes from 33 patients including 16 with neovascular AMD (nvAMD) and 17 controls were included. Patients were included in the present study after a complete ophthalmologic examination, including BCVA, slit-lamp study, intraocular pressure measurement, dilated fundus examination after tropicamide instillation, SD-OCT, SS-OCT, fundus photographs and mfERG. Age, sex, BCVA, number of anti-VEGF intravitreal injections in the nvAMD group, were recollected. Outer retinal and choroidal thickness were determined at the fovea and 500 μm temporal, superior, nasal and inferior. First-order response from mfERG was collected. P1 amplitude was recorded in R1, R2 and the average of R1 + R2. The measurements recollected from the SS-OCT, mfERG and BCVA were compared.ResultsBetter BCVA was found with thicker outer retina foveal thickness (r = 0.349; P = 0.047), with thicker subfoveal choroidal thickness (r = 0.443; P = 0.010), and with higher amplitude in P1 at R1 (r = 0.346; P = 0.037). Outer retina foveal thickness did not correlate with P1 amplitude at R1 (r = 0.072; P = 0.692), R2 (r = 0.265; P = 0.137) either with the average P1 amplitude at R1 + R2 (r = 0.253; P = 0.156). A thicker subfoveal choroidal thickness was related with higher amplitude in P1 at R1 (r = 0.383; P = 0.028), R2 (r = 0.409; P = 0.018) and the average of R1 + R2 (r = 0.419; P = 0.015).ConclusionsChoroidal thickness demonstrated a positive correlation with retinal function in the sample studied, so a thicker choroid is related to a better retinal function measured with mfERG and BCVA.

Pupil response to tropicamide following corneal crosslinking.

To evaluate the effect of corneal crosslinking (CXL) with ultraviolet A (UVA) irradiation on pupil response to tropicamide 0.5% instillation. This prospective interventional study enrolled 17 patients (19 eyes) with progressive keratoconus who underwent CXL with UVA irradiation. Central corneal thickness (CCT) was evaluated with the use of anterior segment optical coherence tomography (Visante OCT 3.0). Pupil diameter was measured with the use of Colvard infrared pupillometer before the instillation of tropicamide 0.5% and after the instillation of tropicamide every 5 minutes for total duration of 30 minutes. Corneal epithelial integrity was examined with the use of fluorescein dye staining. Measurements were performed 1 day preoperatively and 1 month postoperatively, with emphasis on simulating the same light conditions regarding the pupil measurements. No intraoperative or postoperative complications were observed in any of the patients. Mean CCT decreased significantly (p&lt;0.001) 1 month postoperatively. Mean postoperative pupil size did not change significantly at any time point compared to the mean preoperative measurements. The CXL procedure seems not to impair effectiveness of topical drugs, using pupil size measurements after tropicamide 0.5% instillation.

Changes of intraocular pressure and refractive status in children following cycloplegic refraction with 1% cyclopentolate and 1% tropicamide

PurposeTo evaluate the effect of cycloplegic mydriasis with 1% cyclopentolate and 1% tropicamide on the intraocular pressure (IOP) and refractive status of children for cycloplegic refraction and compare the IOP and refractive changes between hyperopic and myopic groups. MethodsThis study was designed as a retrospective cohort study. Ninety one children received cycloplegic mydriasis. The IOP was measured with a noncontact tonometer before cycloplegic administration. One drop of 1% cyclopentolate was administered, which was followed by two drops of 1% tropicamide at an interval of 10 minutes. The IOP was then measured 30 minutes after tropicamide instillation. Autorefraction was assessed with an autorefractometer before and after cycloplegic mydriasis. ResultsThe mean age of the 44 girls and 47 boys was 7.3 ± 2.4 years. The mean precycloplegic IOP was 14.45 ± 2.47 mmHg and the mean postcycloplegic IOP was 15.06 ± 3.08 mmHg in all eyes. A significant difference was noted in the IOP change (p = 0.033). In the 39 hyperopic eyes, the mean precycloplegic IOP and postcycloplegic IOP were 14.54 ± 2.53 mmHg and 15.69 ± 3.35 mmHg, respectively. There was a significant difference in the IOP change (p = 0.008). In the 52 myopic eyes, the mean precycloplegic IOP and postcycloplegic IOP were 14.38 ± 2.44 mmHg and 14.61 ± 2.80 mmHg, respectively (p = 0.72). There was no significant IOP change in the myopic group. The postcycloplegic IOP was significantly different between the hyperopic and the myopic groups (p = 0.021). Three eyes (3.3%) had an IOP elevation more than 5.0 mmHg after cycloplegic mydriasis. Postcycloplegic refraction showed significant hyperopic shifts in all eyes (p < 0.0001). ConclusionCycloplegic mydriasis with 1% cyclopentolate and 1% tropicamide caused IOP changes in preschool and school-aged children with hyperopia. Ophthalmologists should be very cautious in monitoring IOP changes for children with cycloplegic medication use.

Trabecular Meshwork Response to Pressure Elevation in the Living Human Eye

The mechanical characteristics of the trabecular meshwork (TM) are linked to outflow resistance and intraocular pressure (IOP) regulation. The rationale behind this technique is the direct observation of the mechanical response of the TM to acute IOP elevation. Prior to scanning, IOP is measured at baseline and during IOP elevation. The limbus is scanned by spectral-domain optical coherence tomography at baseline and during IOP elevation (ophthalmodynamometer (ODM) applied at 30 g force). Scans are processed to enhance visualization of the aqueous humor outflow pathway using ImageJ. Vascular landmarks are used to identify corresponding locations in baseline and IOP elevation scan volumes. Schlemm canal (SC) cross-sectional area (SC-CSA) and SC length from anterior to posterior along its long axis are measured manually at 10 locations within a 1 mm segment of SC. Mean inner to outer wall distance (short axis length) is calculated as the area of SC divided by its long axis length. To examine the contribution of adjacent tissues to the effect IOP elevations, measurements are repeated without and with smooth muscle relaxation with instillation of tropicamide. TM migration into SC is resisted by TM stiffness, but is enhanced by the support of its attachment to adjacent smooth muscle within the ciliary body. This technique is the first to measure the living human TM response to pressure elevation in situ under physiological conditions within the human eye.

Effect of mydriasis induced by topical 0.5% tropicamide instillation on the corneal biomechanical properties in healthy individuals measured by ocular response analyzer

Purpose: This observational study aims to investigate the effects of tropicamide (0.5%) on corneal biomechanical properties, with the ocular response analyzer (ORA), in healthy individuals.Methods: Corneal hysteresis (CH), corneal resistance factor (CRF), Goldmann-correlated intraocular pressure (IOPg), and corneal-compensated intraocular pressure (IOPcc) measurements of 38 (21 female and 17 male) healthy individuals, before and after 30 min of 0.5% tropicamide instillation, were performed by using the ORA.Results: The mean CH, CRF, IOPg and IOPcc measurements of the eyes were 10.2 ± 1.9 mmHg, 10.3 ± 2.1 mmHg, 15.7 ± 3.4 mmHg, 16.4 ± 3.3 mmHg pre-tropicamide, and 10.4 ± 1.7 mmHg, 10.3 ± 2.1 mmHg, 15.3 ± 3.4 mmHg, 15.8 ± 2.7 mmHg post-tropicamide, respectively. The differences between the pre- and post-tropicamide measurements of the eyes were insignificant (p = 0.184, p = 0.659, p = 0.294, p = 0.150, respectively; paired t-test).Conclusions: A tropicamide instillation does not lead to significant changes in the corneal biomechanical properties. Therefore, it can be used safely in disease, i.e. in the diagnosis and follow-up ORA as it does not cause any change.

Effect of pharmacologic pupil dilation with tropicamide and phenylephrine on wavefront measurements

PurposeTo investigate the influence of tropicamide 1% (as a cycloplegic mydriatic) and phenylephrine 10% (as a noncycloplegic mydriatic) on mydriasis, wavefront refraction, and wavefront aberrations. MethodsIn this prospective study, 31 myopic eyes with a large mesopic pupil size were evaluated with an Allegretto Wave analyzer in a natural dilated state, after instillation of tropicamide 1% or phenylephrine 10%. Aberrations expressed as Zernike polynomials up to the sixth order were analyzed. Wavefront refractions were compared with subjective manifest refraction. ResultsBoth tropicamide and phenylephrine cause significant mydriasis (p < 0.001), but phenylephrine induced a larger pupil size than tropicamide under mesopic conditions (p = 0.029). Compared with the natural state, tropicamide induced a significant hyperopic shift in wavefront refraction (by +0.27 ± 0.09 D; p = 0.002). In contrast, wavefront refraction did not significantly change when using phenylephrine as the mydriatic (+0.03 ± 0.10 D; p = 0.75). Compared with the subjective manifest refraction, wavefront refraction before mydriatics and after phenylephrine showed a significant myopic shift (p < 0.0125), whereas the wavefront refraction after tropicamide was not significantly different from subjective refraction. Zernike coefficient C4 showed a less positive defocus after application of tropicamide (p = 0.0017). Other aberration coefficients of Zernike polynomials up to the sixth order did not change significantly from before to after tropicamide application. There was no significant difference in Zernike coefficients up to C27 before and after phenylephrine. ConclusionPhenylephrine preserves accommodation and provides a larger pupil under mesopic conditions, whereas tropicamide relaxes accommodation and provides an objective wavefront refraction that is closer to the subjective manifest refraction. Neither phenylephrine nor tropicamide causes a significant change in high-order aberrations from the natural state.

Efficacy of temporary lower punctal occlusion in enhancing pupil dilation after 1% tropicamide instillation

Background: Pupil dilatation is essential for complete fundoscopic examinations and some eye surgeries. Whether temporary punctual occlusion will enhance the magnitude of pupillary dilation is not known. Objectives: We measured the pupil diameter after one drop of 1% tropicamide instillation with and without temporary punctal occlusion at 0 and 30 min in the same patient. Methods: Ninety-eight eyes from 49 patients at the Department of Ophthalmology, King Chulalongkorn Memorial Hospital were randomized into temporary punctal occlusion group (group 1) and simple closure group (group 2) after instillation one drop of 1% tropicamide in both eyes. Pupil diameters were photographed and measured before starting the drop and again 30 minutes later for each patient. Results: At 30 minutes the mean pupil sizes of group 1 and group 2 were 3.92±1.53 mm and 3.83±1.43 mm, respectively. The mean difference of pupillary dilatation in group 1 was 2.75±1.94 mm whereas group 2 was 3.19±1.77 mm. The difference between the two group was statistically significant but not clinically important (p = 0.001) (95%CI (-0.69)-(-0.18)). Conclusions: Temporary punctal occlusion could enhance pupil dilation after one drop of 1% tropicamide instillation within 30 minutes. The degree of dilatation was not clinically important. Additional doses of 1% tropicamide or combination preparation will be required for clinically adequate mydriasis. Keywords: Eyelid, punctal, pupil, tear, 1% tropicamide

Efficacy of temporary lower punctal occlusion in enhancing pupil dilation after 1% tropicamide instillation

Background: Pupil dilatation is essential for complete fundoscopic examinations and some eye surgeries. Whether temporary punctual occlusion will enhance the magnitude of pupillary dilation is not known. Objectives: We measured the pupil diameter after one drop of 1% tropicamide instillation with and without temporary punctal occlusion at 0 and 30 min in the same patient. Methods: Ninety-eight eyes from 49 patients at the Department of Ophthalmology, King Chulalongkorn Memorial Hospital were randomized into temporary punctal occlusion group (group 1) and simple closure group (group 2) after instillation one drop of 1% tropicamide in both eyes. Pupil diameters were photographed and measured before starting the drop and again 30 minutes later for each patient. Results: At 30 minutes the mean pupil sizes of group 1 and group 2 were 3.92±1.53 mm and 3.83±1.43 mm, respectively. The mean difference of pupillary dilatation in group 1 was 2.75±1.94 mm whereas group 2 was 3.19±1.77 mm. The difference between the two group was statistically significant but not clinically important (p = 0.001) (95%CI (-0.69)-(-0.18)). Conclusions: Temporary punctal occlusion could enhance pupil dilation after one drop of 1% tropicamide instillation within 30 minutes. The degree of dilatation was not clinically important. Additional doses of 1% tropicamide or combination preparation will be required for clinically adequate mydriasis. Keywords: Eyelid, punctal, pupil, tear, 1% tropicamide

Does prior instillation of a topical anaesthetic alter the pupillary mydriasis produced by tropicamide (0.5%)?

It is common clinical practice to instill a topical anaesthetic prior to the instillation of a mydriatic agent into the eye. The main rationale for using the anaesthetic is to increase corneal permeability, so that more of the mydriatic agent reaches the receptor sites within the anterior chamber. It addition, as mydriatics generally cause stinging, prior use of an anaesthetic should reduce the degree of discomfort. The aim of the present study was to determine whether the efficacy of mydriasis produced by an antimuscarinic agent is enhanced by prior instillation of a topical anaesthetic. The study was performed using a double-masked protocol on 20 healthy young subjects. One drop of either proparacaine (proxymetacaine) (0.5%) or isotonic saline was instilled into the eye, followed by one drop of tropicamide (0.5%). Pupil diameter was measured using a customized photographic device at 0, 10, 20, 30 and 60 min following drug instillation. Additionally, subjects were asked to rate the degree of discomfort following the instillation of each drop on a scale from 0 (no discomfort) to 10 (agony). There was no significant difference in either the rate of onset of mydriasis, or the maximum pupil diameter achieved between the two conditions. The mean change in pupil diameter produced by tropicamide after the instillation of saline or proparacaine was 2.31 and 2.28 mm, respectively. The mean discomfort scores following instillation of saline and proparacaine were 1.15 and 1.65, respectively, while mean discomfort scores following the instillation of tropicamide after saline or proparacaine were 4.00 and 0.85, respectively. Instillation of a topical anaesthetic does significantly reduce the degree of discomfort produced by the instillation of tropicamide. However, it does not produce any significant increase in either the magnitude or rate of onset of mydriasis.

Comparative higher-order aberration measurement of the LADARWave and Visx WaveScan aberrometers at varying pupil sizes and after pharmacologic dilation and cycloplegia

To compare higher-order aberration (HOA) measurements of LADARWave and Visx WaveScan aberrometers, to test the validity of the peripheral wavefront data, and to evaluate the effect of pharmacologic dilation and mild cycloplegia. Thirty-three myopic eyes of 17 volunteers were enrolled and had the ocular HOAs measured and analyzed with varying pupil diameters (PD) controlled by a tunable light intensity source and after instillation of tropicamide 1% and phenylephrine 2.5%. Higher-order aberrations increased with PD and optical zone (OZ), especially an OZ between 6.0 mm and 6.5 mm. Spherical aberration increased the most, followed by coma, then trefoil and secondary astigmatism. Measurement differences were observed between LADARWave and WaveScan at an OZ of 6.0 mm, although measurement correlations between the 2 machines were high. In the case of the WaveScan, when PD = OZ (6.0 mm), the spherical aberration and, to a less extent, the coma data differed from those obtained with larger PDs and the same OZ. In the case of the LADARWave, at an OZ of 6.0 mm, the HOAs measured in eyes with physiologic pupils were similar to those in pharmacologically dilated pupils when the physiologic pupil center was taken as the reference. There were detectable measurement differences between LADARWave and Visx WaveScan. Ensuring that the PD is at least 0.5 mm larger than the desired OZ is very important. Dilation and mild cycloplegia did not clinically affect the wave measurement magnitude or pattern.

Pupil response to tropicamide following LASIK

Pupil response to tropicamide following LASIK

Pupil response to tropicamide following laser in situ keratomileusis

To investigate the effect of corneal thinning after laser in situ keratomileusis (LASIK) on the corneal penetration of topical eye medication. Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA. Laser in situ keratomileusis surgery was performed in 19 eyes of 10 patients enrolled in this prospective study. Measurements were made before surgery and 3 months postoperatively. After instillation of tropicamide 1%, the change in pupil size over time was measured with a Colvard pupillometer. Central corneal thickness (CCT) was measured with ultrasonic pachymetry before and 3 months after LASIK. The corneal epithelial condition was also examined by fluorescein dye staining. The mean CCT decreased significantly from 564 microm +/- 33 (SD) before LASIK surgery to 514 +/- 48 microm 3 months postoperatively (P<.0001). Pupil diameter 10, 15, and 20 minutes after tropicamide 1% instillation was significantly larger 3 months after surgery than preoperatively (P=.0083, P=.0043, and P=.0144, respectively). The mean time to reach a pupil diameter of 6.0 mm decreased significantly from 14.4 +/- 4.3 minutes in preoperative eyes to 11.5 +/- 2.3 minutes in postoperative eyes (P=.0281). Mild punctate corneal epithelial staining (fewer than 5 spots) were observed in 4 eyes at the 3-month postoperative examination. Pupil dilation after tropicamide 1% instillation was significantly faster after LASIK surgery. Corneal thinning that resulted from LASIK enhanced corneal penetration of tropicamide 1%.

Changes in the shape of the anterior and posterior corneal surfaces caused by mydriasis and miosis: Detailed analysis

Purpose: To evaluate changes in the anterior and posterior corneal shape, corneal thickness, and anterior chamber depth (ACD) caused by mydriasis or miosis using scanning-slit corneal topography. Setting: Department of Ophthalmology, Iwate Medical University School of Medicine, Iwate, Morioka, Japan. Methods: Twenty-eight eyes of 28 healthy volunteers with refractive errors of −6.00 to +0.25 diopters were studied. One eye of each subject had instillation of tropicamide–phenylephrine hydrochloride (Mydrin P®) to obtain mydriasis and of pilocarpine hydrochloride 2% (Sanpilo®) to obtain miosis. To assess the corneal shape, the best-fit sphere (BFS), axial power, and tangential power were measured for the anterior and posterior corneal surfaces before and after mydriasis and before and after miosis using scanning-slit corneal topography (Orbscan version 3.0, Orbtek, Inc.). The pupil size, corneal thickness, and ACD were also examined before and after mydriasis and before and after miosis. Results: The mean age of the patients was 31.1 years ± 5.6 (SD) (range 20 to 46 years). The anterior BFS changed from a mean of 8.04 ± 0.3 mm at the time of mydriasis to a mean of 8.00 ± 0.3 mm at the time of miosis. The posterior BFS changed from 6.53 ± 0.3 mm to 6.46 ± 0.3 mm, respectively. Thus, the anterior and posterior cornea became significantly steeper after miosis ( P<.01). The ACD was significantly more shallow after miosis than after mydriasis. However, there was no significant difference in corneal thickness after mydriasis or miosis. Conclusions: The anterior and posterior corneal shapes changed as a result of mydriasis and miosis, and the refractive power of the cornea significantly increased after miosis. To date, changes in refractive power from changes in pupil size have been attributed to a change in the refractive power of the crystalline lens; however, it is now thought that changes in corneal refractive power also occur.

Effect of tropicamide on aqueous flare before and after cataract surgery

PurposeTo examine the effect of tropicamide on flare intensity under phakic and pseudophakic conditions and to differentiate between the possible mechanisms of action of tropicamide on aqueous flare. SettingDepartment of Ophthalmology, Vienna General Hospital, University of Vienna, Vienna, Austria. MethodsIn this prospective study, aqueous flare was measured with the laser flare–cell meter in 20 eyes of 20 patients with age-related cataract enrolled for cataract surgery. Measurements were performed before and 30, 90, and 180 minutes after pupil dilation with tropicamide 0.5%. This measurement was performed in the phakic eye on the day before surgery and in the pseudophakic eye on postoperative days 1, 3, 7, and 28. ResultsAfter tropicamide instillation, aqueous flare decreased preoperatively and on all postoperative days. There was a continuous flare decrease until 3 hours after instillation, reaching a maximum decrease of about 30%. Pupil diameter reached its maximum after 30 minutes. ConclusionTropicamide significantly decreased aqueous flare, seemingly by pharmacological means, not volumetric changes. The time between drug application and measurement should be kept constant.