Comparative Study of the Effects of 1% Atropine on the Anterior Segment

Evaluation of anterior chamber morphology following scleral buckling with Pentacam

PURPOSE

To evaluate anterior segment parameter changes following scleral buckling (SB) surgery for rhegmatogenous retinal detachment (RRD) using the Pentacam Scheimpflug system.

METHODS

Twenty-eight phakic eyes of 28 patients who underwent SB surgery for RDD were included. The anterior chamber volume (ACV), central anterior chamber depth (CACD), mean anterior chamber angle (ACA) and ACA in a specific position (buckle quadrant), and central corneal thickness (CCT) were evaluated preoperatively and at 1 day, 1 week, and 1 and 3 months postoperatively by an anterior Pentacam Scheimpflug method.

RESULTS

The ACV parameters were significantly decreased compared with preoperative levels at 1 day after SB surgery (P = 0.0004), but had no significant differences at 1 week, and 1 and 3 months (P > 0.05). The mean intraocular pressure (IOP) at 1 day was significantly higher than the preoperative level, but no subsequent significant difference was noted between the preoperative IOP and that at 1 week and 1 and 3 months postoperatively (P > 0.05). The CCT at 1 day after surgery increased significantly (P = 0.0122) and subsequently returned to the normal level postoperatively at 1 week and remained stable until 3 months (P > 0.05). The degree of postoperative ACA displayed different changes in the different quadrants and there was a significant increase in the ACA of the buckle quadrants at 1 day (P < 0.0001), 1 week (P = 0.02), and 1 month (P = 0.0266) after surgery, returning to the normal level at 3 months.

CONCLUSIONS

The changes of anterior chamber parameters after SB can be demonstrated by Pentacam both objectively and quantitatively. The ACV and CCT changes were mild and resumed their preoperative parameters after 1 week, while the increase of the ACA at the buckle quadrant returned to normal after 3 months. SB surgeries without encircling or conducted with radial buckling might decrease anterior chamber change.

Characteristics of ciliary muscle profile in high myopes measured by swept-source anterior segment optical coherence tomography

OBJECTIVE

To characterize and compare the ciliary muscle thickness (CMT) between low and high myopes using swept-source anterior segment optical coherence tomography (AS-OCT).

METHODS

Forty visually healthy young Chinese adults aged 18-25 years were divided into two groups based on refractive errors: low myopia (n = 20, spherical-equivalent refractive error (SER) between -0.50 D to -3.00 D) and high myopia (n = 20, SER ≤ -6.00 D). Cycloplegic refractions were performed before axial length (AL) and CMT were measured using a partial coherence laser interferometer and an AS-OCT respectively. CMT was measured perpendicularly to the sclera-ciliary muscle interface at 1 mm (CMT_1), 2 mm (CMT_2), and 3 mm (CMT_3) posterior to the scleral spur, and at the location with maximal thickness (CMT_MAX).

RESULTS

High myopes demonstrated thicker CMT at 2 mm (CMT_2, p = 0.035) and 3 mm (CMT_3, p = 0.003) posterior to the scleral spur, but thinner maximal CMT (CMT_MAX, p = 0.005) than low myopes. The apical CMT_1 and CMT_MAX were also thinner in high myopes than in low myopes (both p< 0.001). CMT_MAX, apical CMT_1, and apical CMT_MAX correlated directly with SER and inversely with AL; in contrast, CMT_2 and CMT_3 showed inverse correlations with SER but direct correlations with AL.

CONCLUSION

Our findings revealed significant differences in CMT between low and high myopes, with high myopes showing thicker CMT at 2 mm and 3 mm posterior to the scleral spur, but thinner maximal CMT. These results provide new evidence of the potential structural differences in ciliary muscles during myopia development and progression.

The effect of atropine used in dobutamine stress echocardiography on pupil diameter

BACKGROUND

The use of atropine during dobutamine stress echocardiography (DSE) is contraindicated in persons with narrow angle glaucoma though there is limited evidence that low doses of intravenous atropine do not cause pupillary dilation.

OBJECTIVE

The aim of this study is to investigate whether atropine when administered in persons without glaucoma during dobutamine stress echocardiography causes pupillary dilation.

METHODS AND RESULTS

Out of 144 patients without a history of glaucoma referred for DSE for clinical indications, 105 patients received intravenous atropine doses ranging from 0.1 mg to 1.25 mg (most patients received 0.25-0.75 mg). Pupil diameter of both eyes was measured under the same light conditions before and after the DSE using a CP-30 Optical Digital PD Ruler. For the total of 210 examined eyes pupil diameter remained unaltered after each DSE test (3.65 ± 0.799 mm before vs 3.63 ± 0.766 mm after, p = .737). Similarly, pupil diameter remained unchanged when left and right eyes were assessed separately (right eye: 3.770 ± 0.812 before vs 3.752 ± 0.745 mm after, p = .821 and left eye: 3.521 ± 0.770 before vs 3.499 ± 0.770 mm after, p = .806). Diameter of right and left pupil were also unaltered after grouping patients by sex and iris pigmentation. Age, weight, atropine dose and propranolol dose were not correlated with changes in pupil diameter.

CONCLUSION

Intravenous atropine in usual doses administered in DSE does not cause mydriasis in adults without glaucoma. Future studies need to confirm our findings and expand the investigation regarding safety of atropine use during DSE in patients with narrow angle glaucoma.