Hasan Ali Bayhan

Coaxial, microcoaxial, and biaxial microincision cataract surgery Prospective comparative study

PURPOSE: To compare the intraoperative and postoperative results of 3 phacoemulsification techniques. SETTING: Atatürk Training and Research Hospital, 2nd Ophthalmology Department, Ankara, Turkey. METHODS: In this prospective randomized study, patients had standard coaxial (2.8 mm incisions), microcoaxial (2.2 mm incisions), or biaxial microincision (1.2 to 1.4 mm trapezoidal incisions) phacoemulsification. Intraoperative phaco parameters and total surgical time were measured and complications recorded. Postoperative visual acuity improvement, pachymetric differences, and surgically induced astigmatism (SIA) results were compared. RESULTS: Each group comprised 45 eyes. There were no significant differences between the 3 groups in demographic, morphologic, or preoperative surgical data. The mean effective phaco time was 2.56 seconds ± 2.46 (SD) in the standard coaxial group, 1.98 ± 1.91 seconds in the microcoaxial group, and 1.29 ± 1.85 seconds in the biaxial microincision group (P<.05). The mean total surgical time was 14.48 ± 4.21 minutes, 13.01 ± 3.66 minutes, and 18.79 ± 6.58 minutes, respectively (P<.01), and the mean measured final incision size was 2.83 ± 0.11 mm, 2.26 ± 0.07 mm, and 1.89 ± 0.21 mm, respectively. The mean SIA 90 days postoperatively was 0.46 diopter (D), 0.24 D, and 0.13 D, respectively (P<.01). There was no statistically significant difference in the complication rate, visual acuity gain, or pachymetric change between the groups (P>.05). CONCLUSIONS: All 3 techniques were reliable, functional, and effective, yielding good visual outcomes and low phaco parameters and complication rates. Biaxial microincision surgery, with the smallest incisions, induced less astigmatism and reduced all intraoperative phaco parameters except total surgical time. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned.

Anterior segment optical coherence tomography evaluation and comparison of main clear corneal incisions in microcoaxial and biaxial cataract surgery

PURPOSE: To use Fourier‐domain anterior segment optical coherence tomography (AS‐OCT)) to evaluate the main clear corneal incisions (CCIs) in microcoaxial and biaxial cataract surgery, the effects of incision enlargement, and the probable reasons for problematic healing. SETTING: Atatürk Training and Research Hospital, 2nd Ophthalmology Department, Ankara, Turkey. DESIGN: Cohort study. METHODS: Eyes that had microcoaxial cataract surgery through a 1.8 mm CCI or biaxial cataract surgery through a 1.2 to 1.4 mm trapezoidal CCI were divided into 2 equal subgroups based on incision enlargement. All surgeries were completed by stromal hydration. Incisions were evaluated 1, 8, and 30 days postoperatively. RESULTS: The CCIs in the microcoaxial group were longer, thinner, and more slanted than those in the biaxial group, with no statistical difference. The microcoaxial incisions had significantly more arcuate configuration at 1 day (P=.003); however, the configuration became linear in the following days in both groups. The endothelial gap rates were less and Descemet membrane detachment rates greater than reported in the literature. In eyes with enlarged CCIs, the endothelial gap rate was higher in the microcoaxial group and the Descemet membrane detachment rate was higher in the biaxial group (both P=.05). At 1 day, the intraocular pressure (IOP) was significantly lower in Descemet membrane detachment and endothelial gap cases (P=.006 and P<.001, respectively). CONCLUSIONS: Although closure was reliable in both groups, the microcoaxial group had slightly fewer undesirable effects on the incision site. Low postoperative IOP seemed to be a significant factor in problematic healing. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned.

Comparison of Corneal Aberrations After Biaxial Microincision and Microcoaxial Cataract Surgeries: A Prospective Study

Purpose: To compare the effects of biaxial microincision cataract surgery (B-MICS) and microcoaxial cataract surgery (C-MICS) techniques on corneal optical quality. Materials and methods: In this prospective study, 40 eyes underwent B-MICS and 40 eyes C-MICS. Corneal aberrations were derived from conversion of the corneal elevation profile into corneal wavefront data with 6.0 mm aperture diameter using Zernike polynomials by corneal topography preoperatively and 1 month postoperatively. Both magnitude and axes of surgically induced corneal aberrations were calculated. Results: Mean final incision widths were 1.80 ± 0.09 mm and 1.89 ± 0.11 mm (p = 0.062) in B-MICS and C-MICS groups, respectively. There were no significant changes in total and higher order root mean square in both groups postoperatively. In B-MICS group, all aberration terms were similar, before and after surgery. However, vertical coma (p = 0.002), vertical trefoil (p < 0.001) and primary trefoil (p = 0.042) significantly increased postoperatively in the C-MICS group. Except surgically induced trefoil (p = 0.047), there was no significant difference in all surgically induced corneal aberrations between groups. The axes of the induced trefoil were found to be mostly related and close to the incision site in both groups which was more prominent in the C-MICS group. Conclusions: Microincision cataract surgery techniques performed through sub-1.9 mm clear corneal incisions do not generally degrade optical quality of the cornea while only small amount of higher order aberrations seem to be induced with C-MICS technique.

Aspheric microincision intraocular lens implantation with biaxial microincision cataract surgery: efficacy and reliability.

PURPOSE: To evaluate the efficacy and reliability of a microincision intraocular lens (IOL) and its use in biaxial microincision cataract surgery (MICS). SETTING: Atatürk Training and Research Hospital, Ankara, Turkey. DESIGN: Prospective clinical study. METHODS: A microincision IOL (Akreos MI60) was implanted after cataract extraction by the biaxial MICS technique. Over a postoperative follow‐up of 12 months or more, visual acuity, contrast sensitivity, surgically induced astigmatism (SIA), corneal and ocular aberrations, and early and late complications were recorded. RESULTS: The IOLs were implanted in the capsular bag in all 100 eyes. The mean final incision size was 1.82 mm ± 0.09 (SD). Postoperatively, the mean corrected distance visual acuity was 0.06 ± 0.10 logMAR; the mean spherical equivalent, −0.48 ± 0.91 diopter (D); and the mean calculated SIA, 0.20 ± 0.22 D. Contrast sensitivity with and without glare was within normal limits. There was no statistically significant difference in the root mean square of total corneal aberrations between preoperatively and postoperatively. Ocular wavefront analysis 3 months postoperatively showed mean values of 0.15 ± 0.2 μm for spherical aberration, 0.38 ± 0.16 μm for higher‐order aberrations, 0.18 ± 0.14 μm for coma, and 0.14 ± 0.08 μm for trefoil. The 4 cases (4.0%) of membranous anterior chamber reaction resolved with treatment. None of the 20 eyes (20.0%) with posterior capsule opacification required neodymium:YAG capsulotomy. All IOLs remained well centered. CONCLUSION: The aspheric microincision IOL was safely implanted through a 1.8 mm or smaller incision during biaxial MICS and gave good postoperative outcomes. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned.

Repeatability of aberrometric measurements in normal and keratoconus eyes using a new Scheimpflug-Placido topographer.

Purpose To evaluate the repeatability of the anterior and posterior corneal wavefront aberrations using the Sirius Scheimpflug–Placido topographer in normal eyes and keratoconus eyes. Setting Bozok University Faculty of Medicine, Yozgat, Turkey. Design Evaluation of diagnostic test. Methods In eyes of healthy subjects and eyes of keratoconus patients, 3 repeated measurements were obtained using the Scheimpflug–Placido topographer. Repeatability of the corneal aberrometric data using a 7th‐order Zernike expansion (6.0 mm pupil) and central corneal power (3.0 mm zone) in the anterior and posterior corneal surfaces were analyzed. The within‐subject standard deviation (Sw) and the intraclass correlation coefficient (ICC) were calculated. Results For all modal pairs, the Sw was 0.08 &mgr;m or less for anterior and posterior corneal aberrations in both groups. The ICC of the anterior corneal surface ranged from 0.607 (pentafoil) to 0.988 (primary coma) in keratoconus eyes (n = 41) and from 0.568 (quadrifoil) to 0.856 (primary coma) in normal eyes (n = 30). The ICCs for posterior corneal surface aberrometry were 0.656 to 0.873 and 0.592 to 0.824, respectively. For anterior and posterior corneal curvatures, the Sw was 0.12 or lower and the ICC values were more than 0.93 in all cases except the posterior corneal surface reading at the 3.0 mm corneal area in keratoconus eyes (ICC 0.875). Conclusions The intraexaminer repeatability of most anterior corneal aberrations with the Scheimpflug–Placido system was moderate to high in normal eyes and keratoconus eyes. The system showed moderate repeatability for the posterior corneal surface. Financial Disclosure No author has a financial or proprietary interest in any material or method mentioned.

The Association of Spectral-Domain Optical Coherence Tomography Determined Ganglion Cell Complex Parameters and Disease Severity in Parkinson’s Disease

Abstract Purpose: To evaluate the association between the retinal structural changes provided by spectral domain optical coherence tomography (SD-OCT) and disease severity in Parkinson’s disease (PD). Materials and methods: Thirty-eight eyes of 20 patients with PD and 30 eyes of 30 healthy subjects were enrolled in this prospective study. The eyes ipsilateral (20 eyes) and contralateral (18 eyes) to the most affected body side in patients with PD were evaluated separately. SD-OCT (RTVue-100) was used to measure the macular ganglion cell complex thickness (mGCC), outer retinal thickness, and peripapillary retinal nerve fiber layer (RNFL) thickness. Disease severity was assessed using Unified Parkinson’s Disease Rating Scale (UPDRS). Results: The differences in the nasal RNFL (p = 0.004), average mGCC (p = 0.014), superior mGCC (p = 0.007), inferior mGCC (p = 0.03) were significant between the ipsilateral eye group and controls. The differences in the nasal RNFL (p = 0.002), and superior mGCC (p = 0.038) were statisticallly significant between the contralateral eye group and controls. Inferior and average mGCC thicknesses of ipsilateral eyes were inversely correlated with UPDRS score (p = 0.001, r = −0.678 and p = 0.009, r = −0.568, respectively). Significant inverse correlation was demonstrated between UPDRS score and inferior RNFL of both eyes ipsilateral and contralateral to the most affected body side. Conclusions: There is significant thinning in mGCC parameters of the retina in PD. The SD-OCT derived mGCC parameters may improve the detection of PD progression.

Choroidal thickness alterations in obstructive sleep apnea–hypopnea syndrome (OSAS)

Sir, We would like to congratulate Xin et al1 on their prospective, observational case–control study of retinal and choroidal thickness (CT) evaluation by spectral domain optical coherence tomography in patients with obstructive sleep apnea–hypopnea syndrome (OSAS). The study presents, for the first time, CT alterations in OSAS patients; however, we think that some important issues need more thorough discussion. The choroid of the eye is one of the most highly vascularized tissues of the body, and it is the major blood supply to the retina.2 It is known that the choroid is prone to suffer from microvascular atherosclerotic changes and changes inherent to other microvascular systems.3 However, the authors did not exclude the subjects having systemic diseases except diabetes, and about 50% of the participants were indicated to have hypertension. Also, hyperlipidemic subjects and smokers were not excluded, although both of them were shown to affect CT.4, 5 As body mass index of OSAS group in their study is significantly higher than that of controls and systemic diseases are often comorbid with OSAS, expecting hypercholesterolemia more in OSAS group is reasonable. It is obvious that including patients having hypertension and other systemic diseases may affect the conclusion of the CT studies. Although the number of the patients and controls having the hypertension are matched, severity and duration of the systemic diseases could not be standardized. Therefore, it should be kept in mind that, CT alterations seen in Xin et als study might be due to the underlying systemic diseases and concomitant treatment in patients. Not only systemic diseases, but also ocular conditions including axial length and refractive error are known to influence CT.6 The authors stated in their study that age and diopter were corrected using covariance analysis before comparing CT between the groups. However, spherical equivalent refraction is not stable throughout life. Myopic shifts can occur especially in elderly patients because of nuclear cataract progression. In this study, OSAS patients tended to be older than controls, although not significantly. So, considering axial length measurements instead of refractive status would be more accurate particularly in old population. Thus, we also wonder that whether the authors paid attention to the concomitant nuclear sclerosis in their patients that might influence the refractive status and consequently the results of their study.

Lipid-containing osmoprotective eye drops in contact lens wearers.

Dear editor We would like to congratulate Kaercher et al1 on their prospective study of Optive Plus (Allergan, Inc., Irvine, CA, USA) in the treatment of patients with dry eye. In this study the authors reported that Optive Plus effectively reduced the signs and symptoms of patients with all types of dry eye and they recommended the use of this artificial tear especially in lipid-deficient dry eye. We think that some important issues need more thorough discussion. It is known that contact lenses (CLs) are becoming increasingly popular and a lot of people have begun to use CLs as an optical correction every day. Unfortunately, it was found that up to 50.1% of CL wearers report a sensation of dryness.2 The presence of a CL has been shown to adversely affect the tear film characteristics, increase tear evaporation, and reduce the ability to produce adequate tears with concurrent increase in tear osmolarity. It has been suggested that increased tear osmolarity may accompany CL-related dry eye and even the most contemporary CL types (ie, silicone hydrogel lenses) can elevate the tear osmolarity.3 The recent report from the Contact Lens Discomfort Workshop reported that tear film changes in CL wearers are responsible for CL discomfort.4 Hyperosmolarity may be the trigger for an inflammatory cascade resulting in the production of inflammatory cytokines which can lead to increased apoptosis of corneal and conjunctival epithelial cells and conjunctival goblet cells.5 Lubricant eye drops that are able to restore the physiological osmolarity of the tear film could reduce the effects of hyperosmotic distress to cells, thus providing osmoprotection. Thus, we think that usage of osmoprotective eye drops can be reasonable in CL wearers. We are also conducting research in dry eye among CL users and we observed that instillation of osmoprotective eye drops (Optive) prevents the increment of tear osmolarity in patients wearing CLs, and Optive has the potential to improve ocular comfort more than the commercially available lubricant solutions. Optive eye drops contain erythritol and L-carnitine osmolytes that have been shown to provide osmoprotection.6 Optive Plus contains the ingredients of Optive in addition to a lipid component, castor oil. The authors1 mentioned in the study that Optive Plus is particularly effective in lipid-deficient dry eye patients. From the design of Kaercher et al’s study,1 we understood that CL usage is not an exclusion criterion. As we know that CL wearing, a common cause of lipid-deficient dry eye, is associated with increased tear evaporation,3 it is expected that lipid-containing osmoprotective artificial tears (eg, Optive Plus) might be more beneficial than other artificial tears for CL related dry eye by replenishing the lipid-depleted tear film and with their osmoprotective effect. However, in clinical practice lipid containing eye drops can induce blurring of vision especially in CL wearers. Thus, we wonder whether the authors should also recommend Optive Plus in patients using CLs and include these patients’ results in their study or whether this particular subgroup of patients is not very appropriate for this therapy due to side effects including blurry vision and was thus excluded from the study.