The Impact of Pupillary Dilation on Intraocular Pressure and Anterior Segment Morphology in Subjects with and without Pseudoexfoliation

Impact of atropine use for myopia control on intraocular pressure in children: A comprehensive review including postpupil dilation intraocular pressure changes

Topical atropine has been widely used for controlling myopia progression in children, yet its long-term efficacy and safety, including potential intraocular pressure (IOP) elevation, are still being studied. The mydriasis and cyclopegia induced by atropine may reduce traction on the trabecular meshwork, together with pigment released into anterior chamber due to the friction between the iris and lens during pupil dilation, may obstruct and reduce the trabecular outflow. This review first explores postdilation IOP changes across different groups - healthy individuals, glaucoma patients, and children. The response to pupil dilation varies widely, with IOP potentially increasing or decreasing. Glaucoma patients, whether with open or closed-angle glaucoma, may experience more significant IOP rises postdilation. The second section examines IOP effects in children using topical atropine for myopia, where most of the 25 reviewed studies showed nonsignificant IOP changes, although slight increases were observed in a few. In addition, no alterations in the retinal nerve fiber layer thickness were found. However, the research on children's IOP under topical atropine is constrained by small sample sizes, cross-sectional studies, brief follow-ups, and often lacks control groups or pretreatment IOP measurements. Given the extended atropine use for myopia and the significant individual variation in IOP response, we recommend routine IOP monitoring for children receiving topical atropine.

The Short-Term Effect of 1% Tropicamide Drop on Pupillary Diameter and Intraocular Pressure Change in Patients With Pseudoexfoliation Material

PRCIS

In this study, in patients with pseudoexfoliation syndrome (PXS) or glaucoma, changes in intraocular pressure (IOP) and pupil size after 1% tropicamide used for pupil dilation, compared with healthy patients were quantitatively demonstrated up to 4 hours after dilation.

PURPOSE

The purpose of this study was to evaluate pharmacological dilatation with one drop of 1% tropicamide on pupillary diameter and IOP changes in patients with PXS and glaucoma (PXG).

MATERIALS AND METHODS

Eighty-two patients with PXS, 78 Patients with PXG, and 35 healthy subjects were included in the study. PXG and PXS were diagnosed based on IOP assessment, corneal pachymetry, optic disc examination, visual field testing, and peripapillary retinal nerve fiber analysis. IOP and the diameter of pupil size were measured before dilatation and at postdilatation first, second, and fourth hours.

RESULTS

The mean pupillary diameter values at postdilatation second and fourth hours were statistically significantly different between the patients with PXS and PXG ( P <0.001, for each). Also, there were significant differences between the PXS group and the control group in terms of the mean pupillary diameter values at predilatation and postdilatation at the first hour and postdilatation second hour ( P =0.007, <0.001, respectively). The mean pupillary diameter at all times was statistically significantly different between PXG and control groups ( P <0.001 for each). Significant IOP increases were observed in all groups after dilatation. The mean IOP at predilatation and postdilatation fourth hour was statistically significantly different between PXG and PXS groups ( P =0.042, <0.001, respectively). Whereas the mean IOP at predilatation, postdilatation first hour, postdilatation second hour, and postdilatation fourth hour were statistically significantly different between PXG and control group ( P <0.001 for each).

CONCLUSIONS

Significant IOP increases have been observed in our study with 1% tropicamide in the PXG and PXS groups, with the peak effect at the second hour in the postdilatation period. Furthermore, the mean pupil diameter was found to be significantly lower in PXG patients compared with the control group.

Apoptosis inhibitor of macrophages/CD5L enhances phagocytosis in the trabecular meshwork cells and regulates ocular hypertension

The trabecular meshwork (TM) cells of the eye are important for controlling intraocular pressure (IOP) and regulating outflow resistance in the aqueous humor. TM cells can remove particles and cellular debris by phagocytosis, decreasing both outflow resistance and IOP. However, the underlying mechanisms remain unclear. Here, we investigate whether apoptosis inhibitor of macrophages (AIM), which mediates the removal of dead cells and debris in renal tubular epithelial cells, regulates the phagocytic capacity of TM cells. In vitro experiments revealed that CD36, the main receptor for AIM, colocalized with AIM in human TM cells; additionally, phagocytosis was stimulated when AIM was provided. Furthermore, in a mouse model with transient IOP elevation induced by laser iridotomy (LI), removal of accumulated iris pigment epithelial cells or debris in the TM and recovery of IOP to baseline levels were delayed in AIM-/- mice, compared with control mice. However, treatment with AIM eyedrops rescued AIM-/- mice from the elevated IOP after LI. Since AIM is a protein known to inhibit macrophage apoptosis, we additionally verified its involvement in macrophage removal of cellular debris and IOP. There were no statistically significant differences in the number of macrophages between control mice and AIM-/- mice in the TM. Additionally, we confirmed the rescue effect of the rAIM eyedrops after macrophages had been removed by clodronate liposomes. Therefore, AIM plays an important role in regulating the phagocytic capacity of TM cells, thereby affecting outflow resistance. Our results suggest that drugs targeting the phagocytic capacity of TM cells via the AIM-CD36 pathway may be used to treat glaucoma.

Effectiveness of topical cycloplegics as anterior segment analgesics: systematic review and meta-analysis

OBJECTIVE

Topical cycloplegic agents often are used in ophthalmology in the context of management of ocular inflammation. Preliminary searches of the literature provided little evidence to support their use in relieving pain or reducing inflammation. The goal of this study was to evaluate the current literature for any evidence regarding the effectiveness of cycloplegics for treatment of pain or inflammation in patients with anterior segment injury or inflammation through a systematic review and meta-analysis.

METHODS

Using multiple keywords relating to cycloplegics and inflammatory and infectious eye conditions, a search was conducted on multiple scientific databases for relevant articles. A 2-level screening approach was used and articles that were relevant to the topic were included in the systematic review. Data from these articles, if applicable, were extracted for meta-analyses. Statistical assessments involved computation of I²statistics, Z-value, and χ² statistics.

RESULTS

We screened 5753 articles for relevance. Seven were included in the systematic review and 5 were included in the meta-analysis. There was considerable heterogeneity between the included studies. Statistical analysis revealed significant reductions in pain using homatropine and cyclopentolate after 2 days. Nonsignificant changes in the anterior chamber cells and flare were seen using cyclopentolate and atropine at different follow-up times.

CONCLUSIONS

Little published evidence exists in the literature to guide the use of cycloplegics on relieving pain and treating inflammation. Therefore, higher-quality randomized controlled trials with longer follow-up times are needed to fully understand the role that cycloplegics play in reducing pain in inflammatory conditions.

A Case of Bilateral Delayed-onset Hyphema Following Pupil Dilation after Gonioscopy-assisted Transluminal Trabeculotomy

Aim and objective

To present a case of bilateral delayed-onset hyphema following the administration of a 1% tropicamide and 2.5% phenylephrine fixed combination ophthalmic agent, in the late follow-up period of a gonioscopy-assisted transluminal trabeculotomy (GATT) combined with cataract extraction.

Background

Gonioscopy-assisted transluminal trabeculotomy consists on a 360° trabeculotomy through an ab interno approach that may also be combined with cataract surgery. Delayed-onset hyphema has been reported with trabecular minimally invasive glaucoma surgery (MIGS) procedures. Some proposed mechanisms are ocular compression and decompression during sleeping on the surgical side and episcleral venous pressure rise after physical activity.

Case description

We describe the case of a 68-year-old female patient with ocular hypertension (OHT) and bilateral cataracts who underwent uncomplicated combined GATT and cataract extraction surgery. Postoperatively, 8 months after the left eye (OS) surgery and 3 months after the right eye (OD) surgery, patient came for routine evaluation. After induced mydriasis, slit-lamp evaluation revealed the presence of 3+ OD and 4+ OS erythrocytes in the anterior chamber (AC). Prednisolone acetate was prescribed q.i.d. and remission of hyphema was achieved after 2 weeks. Subsequently, 4 months later, the pupil dilation was again induced showing 4+ erythrocytes in both eyes (OU), layered hyphema in the inferior quadrant OS, and intraocular pressure (IOP) spike OU. The intraocular pressure was controlled after oral acetazolamide was prescribed. Topic prednisolone was initiated, and after 1 week, the hyphema was resolved in OU.

Conclusion

Delayed-onset microhyphema may occur following induced mydriasis even months after the uncomplicated GATT procedure. Ophthalmologists should be aware of the possibility of microhyphema after induced mydriasis and the risks that this might represent with noteworthy and repeated IOP spikes which may eventually require treatment.

Clinical significance

Delayed-onset hyphema and IOP spikes may occur following the pupil dilation with fixed combination of phenylephrine and tropicamide ophthalmic agent after the uncomplicated GATT procedure.

How to cite this article

Espinoza G, Rodriguez-Una I, Pedraza-Concha A. A Case of Bilateral Delayed-onset Hyphema Following Pupil Dilation after Gonioscopy-assisted Transluminal Trabeculotomy. J Curr Glaucoma Pract 2020;14(2):72-75.

Effect of pupil dilation on biometric measurements and intraocular lens power calculations in schoolchildren

Purpose

To investigate the effect of pupil dilation on ocular biometric parameters and intraocular lens (IOL) power calculation in schoolchildren using the Lenstar LS 900.

Methods

One hundred forty eyes of 140 healthy schoolchildren were included in the analysis. Axial length (AL), central corneal thickness (CCT), aqueous depth (AD), anterior chamber depth (ACD), lens thickness (LT), flat keratometry (K), steep K, astigmatism, white-to-white (WTW), and iris/pupil barycenter distance were measured, before and after pupil dilation. Anterior segment length (ASL) was defined as the sum of ACD and LT, and lens position (LP) was defined as ACD plus half of the LT. The relative lens position (RLP) was defined as LP divided by AL. IOL power was calculated using the eight formulas (Hill-RBF, Barrett, Haigis, Hoffer Q, Holladay, Olsen, SRK II, and SRK/T) integrated in the Lenstar LS 900. Parameters before and after pupil dilation were compared.

Results

AL, AD, ACD, LT, ASL, LP, RLP, flat K, iris barycenter distance, pupil barycenter distance, and PD differed significantly after pupil dilation (P < 0.001 in all cases), as compared to before dilation. The Olsen formula demonstrated significant differences in the magnitude of astigmatism (P = 0.010) and IOL power (P = 0.003) after pupil dilation. Using the different formulas, 23.6–40.7% of participants had IOL power changes of more than 0.50 diopters, while 0.7–1.4% had IOL changes of more than 1.0 diopter after pupil dilation.

Conclusions

Dilated and undilated pupil size affected the Lenstar LS 900 measurement of some ocular biometric parameters, and pupil dilation led to IOL power changes exceeding 0.50 diopters with a high percentage (from 23.6% to 40.7%) in schoolchildren, which should be noticed in clinical practice.

Non-continuous measurement of intraocular pressure in laboratory animals

Glaucoma is a leading cause of blindness, which is treatable but currently incurable. Numerous animal models therefore have both been and continue to be utilized in the study of numerous aspects of this condition. One important facet associated with the use of such models is the ability to accurately and reproducibly measure (by cannulation) or estimate (by tonometry) intraocular pressure (IOP). At this juncture there are several different approaches to IOP measurement in different experimental animal species, and the list continues to grow. We feel therefore that a review of this subject matter is timely and should prove useful to others who wish to perform similar measurements. The general principles underlying various types of tonometric and non-tonometric techniques for non-continuous determination of IOP are considered. There follows discussion of specific details as to how these techniques are applied to experimental animal species involved in the research of this disease. Specific comments regarding anesthesia, circadian rhythm, and animal handling are also included, especially in the case of rodents. Brief consideration is also given to possible future developments.