The effectiveness of disc synoptoscope on patients with abnormal binocular vision: a prospective cohort study

Purpose

We performed a prospective cohort study to evaluate the effectiveness of disc synoptoscope on binocularity in patients with abnormal binocular vision.

Methods

39 eligible subjects were recruited for visual therapy with disc synoptoscope in treatment group and 38 were just observed as control.

Results

Simultaneous perception in treatment group was better than controls at 6-month visit (p < 0.05). Fusional amplitude improved in treatment group but decreased in control group at 3- and 6-months visits (p < 0.001). Near and distance stereopsis in treatment group were better than controls at 3- and 6-months (p < 0.05). The improvements of monocular and binocular acuity in treatment group were better than controls at 3- and 6-months (p < 0.05). Postoperative recurrence rate in treatment group was lower than controls (p < 0.05).

Conclusion

Visual therapy with disc synoptoscope is effective in improving short-term binocular vision for the patients with abnormal binocular vision; disc synoptoscope could serve as an effective home-based visual therapy instrument.

     

<Emphasis Type="Italic">MTHFR</Emphasis> and <Emphasis Type="Italic">MTHFD1</Emphasis> gene polymorphisms are not associated with pseudoexfoliation syndrome in South Indian population

Purpose

Pseudoexfoliation syndrome (PEX) is a late onset disorder of extracellular matrix turnover, associated systemically with cardiovascular and cerebrovascular disease. To evaluate the suggested association of polymorphisms of homocysteine metabolism genes MTHFR (rs1801131, rs1801133) and MTHFD1 (rs8006686) with PEX.

Methods

A case–control association study was undertaken, comprising a total of 1472 individuals including 860 unrelated PEX cases and 612 ethnic-matched cataract controls (CC). All the study subjects were genotyped for three SNPs using the TaqMan allelic discrimination assay. Association and statistical analysis were performed with PLINK 1.07 and STATA 11.1.

Results

Among the three SNPs genotyped, MTHFR polymorphisms did not exhibit significant association with PEX (rs1801131; p = 0.549, rs1801133; p = 0.408). The intronic SNP rs8006686 showed nearly significant association (p = 0.069), and however did not remain significant after Bonferroni correction.

Conclusion

Our study suggests no significant genetic association of MTHFR (rs1801131, rs1801133) and MTHFD1 (rs8006686) polymorphisms in South Indian PEX patients.

     

Assessing posterior ocular structures in β-thalassemia minor

Purpose

The aim of this study was to investigate the effect of β-thalassemia minor on choroidal, macular, and peripapillary retinal nerve fiber layer thickness.

Methods

To form the sample, we recruited 40 patients with β-thalassemia minor and 44 healthy participants. We used spectral-domain optical coherence tomography to take all measurements of ocular thickness, as well as measured intraocular pressure, axial length, and central corneal thickness. We later analyzed correlations of hemoglobin levels with ocular parameters.

Results

A statistically significant difference emerged between patients with β-thalassemia minor and the healthy controls in terms of mean values of subfoveal, nasal, and temporal choroidal thickness (p = 0.001, p = 0.016, and p = 0.010, respectively). Except for central macular thickness, differences in paracentral macular thicknesses between the groups were also significant (superior: p < 0.001, inferior: p = 0.007, temporal: p = 0.001, and nasal: p = 0.005). Also, no statistically significant differences were noted for retinal nerve fiber layer thickness between two groups.

Conclusion

Mean values of subfoveal, nasal, temporal choroidal, and macular thickness for the four quadrants were significantly lower in patients with β-thalassemia minor than in healthy controls.

     

Alterations in corneal epithelial thickness in patients with congenital myogenic eyelid ptosis

Purpose

To evaluate whether the corneal epithelial thickness (CET) maps obtained by optical coherence tomography (OCT) of the congenital myogenic eyelid ptosis differ from controls.

Methods

CET maps of 13 patients with congenital myogenic eyelid ptosis (m/f = 9/4; mean age 20.5 ± 7.5) and randomly selected one eye of 13 controls (m/f = 7/6; mean age 21.5 ± 6.5) were investigated. Three pachymetry scans of each eye were performed by OCT (RTVue-XR, Optovue Inc., USA), and the scan with the highest signal strength index was selected for the analysis.

Results

In ptosis group: Minimum corneal epithelial thickness was thinner (p = 0.029), standard deviation of thickness was higher (p = 0.039), the negative of min–max values were higher (p = 0.007). This difference was originating from the significant thinness of the superior sectors (S, SN, ST) of the corneal epithelium than the inferior counterparts (I, IT, IN) (p = 0.001, p = 0.017, p = 0.002), respectively. There was no difference regarding total corneal thickness measurements.

Conclusions

The mechanic effects of ptotic eyelid to the ocular surface may reshape the corneal epithelium, which can be objectively detected by OCT.

     

The association of <Emphasis Type="Italic">Helicobacter pylori</Emphasis> with choroidal and retinal nerve fiber layer thickness

Purpose

To investigate the effect of Helicobacter pylori (H. pylori) infection on choroidal thickness (CT) and retinal nerve fiber layer thickness (RNFLT).

Methods

The study included 25 patients with H. pylori infection and 25 healthy individuals as the control group. Helicobacter pylori patients were classified as the pre-treatment (Group 1; n: 25) and the post-treatment (Group 2; n: 25). RNFLT and CT were measured before and after treatment of H. pylori infection, using enhanced depth imaging (EDI) spectral-domain optical coherence tomography (Spectralis, Heidelberg Engineering, Heidelberg, Germany). The axial length and intraocular pressure were also measured.

Results

The mean subfoveal CT was 320.96 ± 29.15 μm in Group 1 and 287.48 ± 49.17 in the control group (p = 0.007), while the mean subfoveal CT did not show any difference between Group 2 and the control group (p > 0.05). No statistically significant difference was determined between the H. pylori patients and the control group in respect of RNFLT values (p > 0.05).

Conclusions

CT increases during H. pylori infection and returns to the normal range within 6 weeks of treatment. RNFLT does not show any change during H. pylori infection. The data related to the subfoveal CT may be useful in understanding the pathogenesis of central serous chorioretinopathy developing in H. pylori patients.

     

Dry eye evaluation and correlation analysis between tear film stability and corneal surface regularity after small incision lenticule extraction

Purpose

To investigate the dry eye after small incision lenticule extraction (SMILE) and explore the correlations between changes in the tear film stability, the tear secretion and the corneal surface regularity.

Methods

Sixty-two eyes of 22 men and 13 women who underwent SMILE were included in this study. Corneal topography was measured to assess the index of surface variance (ISV) and the index of vertical asymmetry (IVA). Dry eye tests including subjective symptom questionnaire, tear breakup time (TBUT), corneal fluorescein staining and Schirmer’s test (ST) were evaluated before and at 1 and 6 months postoperatively.

Results

TBUT was found to be significantly decreased from 9.8 ± 3.4 s preoperatively to 7.4 ± 3.8 s at 1 month and 6.5 ± 3.6 s at 6 months (both P < 0.001). There was a significant decrease in ST at 1 month postoperatively (P = 0.012); however, ST returned to baseline by 6 months (P = 0.522). Both ISV and IVA significantly increased after the surgery (all P < 0.001). In addition, the changes in TBUT were negatively correlated with the increases in ISV and IVA (r = ?0.343, P = 0.006 and r = ?0.311, P = 0.014, respectively).

Conclusions

Patients undergoing SMILE might develop a short-TBUT type of dry eye. Corneal surface regularity indices might be helpful in the assessment of tear film stability following SMILE procedure.

     

Comparison of biometric measurements obtained by the Verion Image-Guided System versus the auto-refracto-keratometer

Purpose

To compare the biometric measurements obtained from the Verion Image-Guided System to those obtained by auto-refracto-keratometer in normal eyes.

Methods

This is a prospective, observational, comparative study conducted at the Asociación para Evitar la Ceguera en México I.A.P., Mexico. Three sets of keratometry measurements were obtained using the image-guided system to assess the coefficient of variation, the within-subject standard deviation and intraclass correlation coefficient (ICC). A paired Student t test was used to assess statistical significance between the Verion and the auto-refracto-keratometer. A Pearson’s correlation coefficient (r) was obtained for all measurements, and the level of agreement was verified using Bland–Altman plots.

Results

The right eyes of 73 patients were evaluated by each platform. The Verion coefficient of variation was 0.3% for the flat and steep keratometry, with the ICC being greater than 0.9 for all parameters measured. Paired t test showed statistically significant differences between groups (P = 0.0001). A good correlation was evidenced for keratometry values between platforms (r = 0.903, P = 0.0001 for K1, and r = 0.890, P = 0.0001). Bland–Altman plots showed a wide data spread for all variables.

Conclusion

The image-guided system provided highly repeatable corneal power and keratometry measurements. However, significant differences were evidenced between the two platforms, and although values were highly correlated, they showed a wide data spread for all analysed variables; therefore, their interchangeable use for biometry assessment is not advisable.

     

Comparison of visual outcomes and reading performance after bilateral implantation of multifocal intraocular lenses with bilateral monofocal intraocular lenses

Purpose

To compare the visual acuity outcomes, contrast sensitivity function (CS) and reading ability in patients with bilateral multifocal intraocular lenses and patients with bilateral monofocal lenses.

Setting

Vizyon Eye Center, Denizli, Turkey.

Design

Comparative case series.

Methods

Consecutive bilateral cataract patients having implantation of Acriva Reviol MFM 611 multifocal IOLs (Group A) or Acriva BB UD 613 monofocal IOLs (Group B) were included. Parameters analyzed 6 months postoperatively included monocular uncorrected distance (UDVA), binocular uncorrected intermediate (UIVA), binocular uncorrected near (UNVA), CS and bilateral reading performance using MN Read.

Results

The study evaluated 42 eyes in Group A and 40 eyes in Group B. There were no statistically significant differences in UDVA between two groups postoperatively (p = .39). Binocular UIVA and binocular UNVA are better in Group A (p = .00, p = .00). Under photopic and scotopic conditions, contrast sensitivity results were decreased in Group A, especially at high spatial frequencies. No statistically difference were found in reading acuity, critical print size and maximum reading speed between two groups (p = .57, p = .62, p = .22).

Conclusions

This study concludes that multifocal lenses are reliable and efficient replacements for reading glasses since they significantly improve the vision for near or intermediate distance activities.

     

Surgical outcomes of 27-gauge pars plana vitrectomy with short-term postoperative tamponade of perfluorocarbon liquid for repair of giant retinal tears

Purpose

To investigate the use of 27-gauge pars plana vitrectomy (PPV) with short-term tamponade of perfluorocarbon liquid (PFCL) for repair of giant retinal tears (GRT).

Methods

Retrospective case series study. Consecutive patients with GRT were treated with 27-gauge PPV and short-term tamponade of PFCL for 7–10 days. PFCL was completely removed with a secondary surgery.

Results

Twenty-three eyes of 23 patients were included. All the patients achieved primary anatomic success. Preoperative logarithm of the minimum angle of resolution (logMAR) BCVA was 1.59 ± 0.58 (Snellen 20/778). Five (21.7%), nine (39.1%), eleven (47.8%) and fifteen (65.2%) eyes experienced vision improvement at the Month-1, Month-3, Month-6 and final follow-ups, respectively. The final logMAR BCVA was 0.84 ± 0.51 (Snellen 20/138), being statistically better than the preoperative one (P < 0.001). Surgical complications included foreign body response (n = 7), transient elevated intraocular pressure (n = 5), cataract formation/deterioration (n = 11) and posterior capsule opacity (n = 16).

Conclusions

27-Gauge PPV with short-term tamponade of PFCL is safe and effective for the repair of GRT. Side effects of the surgery mainly included foreign body response, transient elevated intraocular pressure, cataract formation/deterioration and posterior capsule opacity.

     

Characteristics of successful filtering blebs at 1 year after trabeculectomy using swept-source three-dimensional anterior segment optical coherence tomography

Purpose

To identify the cross-sectional characteristics of filtering blebs associated with intraocular pressure (IOP) control at 1 year after trabeculectomy with a square scleral flap and a fornix-based conjunctival flap.

Methods

A retrospective consecutive case series study was conducted. Eighty-four eyes of 79 patients who had undergone primary trabeculectomy were included. Surgical success was defined as IOP ≤15 mmHg and a >20% reduction in IOP without glaucoma medication and without additional glaucoma surgery at 1 year after trabeculectomy. The subjects were classified into two groups according to whether surgery was successful or unsuccessful. Filtering blebs were examined using swept-source three-dimensional anterior segment optical coherence tomography and evaluated for the following quantitative parameters: maximum bleb height, maximum bleb wall thickness, and ratio of hypo-reflective space of the bleb wall.

Results

Sixty-six eyes were determined to be successful and 18 eyes unsuccessful. Univariate analysis showed significant differences between the two groups regarding bleb height (P < 0.001), bleb wall thickness (P = 0.011), and ratio of hypo-reflective space of the bleb wall (P = 0.002). Multivariate logistic regression analysis confirmed that the bleb height was significantly associated with success in trabeculectomy [odds ratio 13.996 (95% confidence interval 1.184–165.420); P = 0.036].

Conclusion

A tall bleb with a thick hypo-reflective wall may be a feature of the well-functioning bleb.

     

Methicillin resistance and biofilm production of <Emphasis Type="Italic">Staphylococcus epidermidis</Emphasis> isolates from infectious and normal flora conjunctiva

Purpose

Coagulase-negative staphylococci have been reported to be the most frequent cause of bacterial postoperative endophthalmitis. Biofilm formation is the major virulence factor of Staphylococcus epidermidis and is often associated with methicillin resistance. This study aims at evaluating the presence of biofilm-producing and methicillin resistance genes (mecA) in S. epidermidis.

Methods

S. epidermidis isolated from clinically infected sites (group 1) and from normal human conjunctiva (group 2) were studied. All the isolates were tested for their ability to produce biofilm by the conventional Christensen´s method and the presence of mecA by PCR using the 22-mer oligonucleotides as primers.

Results

In total 20 isolates from group 1 and 22 from group 2 were studied. Biofilm and mecA were detected in 15 (75 %) and in 14 (70 %) in group 1 as compared to 8 (36.3 %) and 4 (18.2 %) in group 2 (p = 0.016). Simultaneously, biofilm production and presence of mecA genes were observed in 13/20 (65.0 %) in group 1, and 4/22 (18.2 %) in group 2 (p = 0.002). Multi-resistance was observed in 55 % in group 1 and 9 % in group 2 (p = 0.002); 57 % of the biofilm-producing strains was multi-resistant in contrast to none of the non-producing strains. In all multi-resistant strains, biofilm production was seen.

Conclusions

Biofilm formation capacity was widely distributed, particularly among mecA (+) S. epidermidis strains, which also displayed a high diversity of antibiotic resistance profiles.

     

Optical coherence tomography shows early loss of the inferior temporal quadrant retinal nerve fiber layer in autosomal dominant optic atrophy

Purpose

The aim of the study was to evaluate the relationship between visual function and retinal nerve fiber layer thickness (RNFLT) determined using Stratus optical coherence tomography (OCT) in patients with autosomal dominant optic atrophy (ADOA).

Methods

The study was a retrospective, institutional, and comparative case series. Thirty-six consecutive patients with ADOA and 72 age-matched normal controls were compared with regard to RNFLT, best-corrected visual acuity (BCVA), and visual field.

Results

The relative reduction of RNFLT of ADOA patients was most evident in the temporal quadrant (56.8 %), followed by the inferior (35.5 %), superior (27.2 %), and nasal quadrants (26.4 %). In ADOA patients, BCVA decreased with RNFL thinning (p?<?0.001), and was not related to age (p?=?0.210). Papillomacular bundle RNFLT decreased with age throughout the study period of 3.7?±?2.3 years (?3.83?±?9.96 μm, p?=?0.017). The presence of a superotemporal central scotoma (61.1 %) was related to decreased inferotemporal RNFLT (7 and 8 o’clock, p?=?0.016 and p?=?0.036, respectively).

Conclusions

The papillomacular bundle RNFL of ADOA is most vulnerable and progressively damaged with age, despite early temporal RNFL loss. Early loss of inferior temporal RNFL in ADOA is related to superotemporal central scotoma.

     

Is keratoconus more severe in pediatric population?

Purpose

To compare the ophthalmic parameters and the severity of keratoconus (KC) in pediatrics and adults at the time of initial diagnosis in an Iranian population.

Methods

KC was diagnosed via slit-lamp examination and Pentacam imaging. In a retrospective observational study, consecutive patients were divided into two groups of pediatrics (<18 years old) and adults (>18 years old). Topographic, keratometric, and tomographic parameters, and severity of KC at the time of diagnosis were compared in both groups. Severity of KC was classified according to Amsler–Krumeich classification.

Results

One hundred fifty-eight eyes of 158 pediatric patients and 343 eyes of 343 adults with KC were studied. The mean ages of the pediatric and adult patients were 15 ± 1.9 and 22 ± 1.9 years, respectively (p < 0.001). The results revealed that pediatric patients had significantly higher values of anterior and posterior mean, flat and steep keratometry, astigmatism, and maximum elevation and significantly lower central and thinnest corneal thickness (p < 0.05). No significant difference was found regarding sphere, cylinder, manifest refraction spherical equivalent, and uncorrected and best-spectacle corrected visual acuity between the groups (p > 0.05). Pediatric patients had a significantly more severe KC than adult patients according to Amsler–Krumeich classification (p = 0.001).

Conclusion

Our findings suggest that KC is more severe in pediatrics, hence the fact that they should be closely monitored and intensively treated.

     

Effects of alpha-lipoic acid on retinal ganglion cells,retinal thicknesses,and VEGF production in an experimental model of diabetes

Purpose

The purpose of the present study was to investigate the effect of alpha-lipoic acid (ALA) on the thicknesses of various retinal layers and on the numbers of retinal ganglion cells and vascular endothelial growth factor levels in experimental diabetic mouse retinas.

Methods

Twenty-one male BALB/C mice were made diabetic by the intraperitoneal administration of streptozotocin (200 mg/kg). One week after the induction of diabetes, the mice were divided randomly into three groups: control group (non-diabetic mice treated with alpha-lipoic acid, n = 7), diabetic group (diabetic mice without treatment, n = 7), and alpha-lipoic acid treatment group (diabetic mice with alpha-lipoic acid treatment, n = 7). At the end of the 8th week, the thicknesses of the inner nuclear layer (INL), outer nuclear layer (ONL), and full-length retina were measured; also retinal ganglion cells and VEGF expressions were counted on the histological sections of the mouse retinas and compared with each other.

Results

The thicknesses of the full-length retina, ONL, and INL were significantly reduced in the diabetic group compared to the control and ALA treatment groups (p = 0.001), whereas the thicknesses of these layers did not show a significant difference between ALA treatment and control groups. The number of ganglion cells in the diabetic group was significantly lower than those in the control and ALA treatment groups (p = 0.001). The VEGF expression was significantly higher in the diabetic group and mostly observed in the ganglion cell and inner nuclear layers compared to the control and ALA treatment groups (p = 0.001). Therefore, the number of ganglion cells and VEGF levels did not show significant differences between the ALA treatment and control groups (p = 0.7).

Conclusions

Our results show that alpha-lipoic acid treatment may have an impact on reducing VEGF levels, protecting ganglion cells, and preserving the thicknesses of the inner and outer layers in diabetic mouse retinas.

     

The role of patient’s systemic characteristics and plateletcrit in developing toxic anterior segment syndrome after uneventful phaco surgery: A case–control study

Purpose

To compare the systemic and ocular characteristics and laboratory findings of patients developing toxic anterior segment syndrome (TASS) after uneventful phaco surgery with unaffected subjects undergoing the same surgery in the same session.

Design

A retrospective case–control study.

Methods

The study group consisted of 26 eyes of 26 patients who underwent uneventful phaco surgery and who went on to develop TASS, while the control group included 39 subjects who had routine phaco surgery in the same session by the same surgeon. The sterilization stages of reusable instruments, disposable instruments, and compositions were recorded. The preoperative systemic diseases, complete blood count parameters, glycosylated hemoglobin (HbA1c), biochemical parameters, thyroid hormone profiles, and the surgical features were compared between the two groups.

Results

Type 2 diabetes mellitus (DM), systemic hypertension (HT), hyperlipidemia, chronic ischaemic heart disease, and chronic renal failure were significantly more common in the TASS group (p < 0.05). Proliferative diabetic retinopathy was also more frequent in the TASS group (p = 0.003). Mean HbA1c% values, white blood cell count, neutrophil/lymphocyte ratio, platelet counts, platelet distribution width, and plateletcrit parameters were significantly higher in the TASS group (p < 0.05). Multivariate logistic regression analysis revealed that a high plateletcrit level (p = 0.001, odds ratio [95% CI]; 22.27 [3.36–147.76]) and systemic HT (p = 0.044, odds ratio [95% CI]; 7.13 [1.05–48.12]) are independently associated with the development of TASS.

Conclusion

Although TASS may arise as a result of insufficient sterilization of instruments or intraocular solutions, patient factors may also contribute to its development. Systemic vascular disorders such as uncontrolled type 2 DM, systemic hypertension, and hyperlipidemia may increase the risk of TASS after uneventful phaco surgery. Abnormal parameters associated with systemic inflammation, such as higher plateletcrit level, may facilitate the development of TASS. These findings may be a predicting factor of TASS development for uneventful cataract surgeries.

     

Correlative factors’ analysis of postural-related ocular cyclotorsion with image-guided system

Purpose

To explore the correlation between ocular cyclotorsion induced by sitting and supine positions as well as other selected factors, validated by an image-guided system.

Study design

A cross-sectional study conducted in 73 inpatients (85 eyes) who received intraocular operations in China Medical University.

Methods

The ocular cyclotorsion degree was recorded using an image-guided system (Verion Reference Unit, Alcon) by comparing images captured in sitting position, as well as pre- and post-different anesthesia methods in the supine position. Possible correlative factors including age, gender, eye axial length, best corrected visual acuity (BCVA), astigmatism degree, astigmatism axis, anesthesia, and comparison in laterality of eyes on ocular cyclotorsion were analyzed.

Results

The total cyclotorsion rate was 88.24% and the cyclotorsion degree ranged from ? 14.0° to + 12.0° with an average of 4.6° ± 3.4°. Excyclotorsion was predominant OD whereas incyclotorsion was predominant OS (p < 0.05). The effect of eye axial length, BCVA, astigmatism degree, astigmatism axis, anesthesia method, age and gender on cyclotorsion orientation was not statistically significant, neither did these factors show any significant differences in the ocular cyclotorsion degree (p > 0.05). Pre- and post-anesthesia, and different anesthetic methods, did not show any significant influence on the ocular cyclotorsion degree (p > 0.05).

Conclusions

Cyclotorsion orientation seems to be correlated only with eye laterality. None of the other investigated factors, including age, gender, eye axial length, BCVA, astigmatism degree, astigmatism axis and anesthesia seems to affect cyclotorsion orientation or degree.

     

Additive effects of orthokeratology and atropine 0.01% ophthalmic solution in slowing axial elongation in children with myopia: first year results

Purpose

To investigate the additive effects of orthokeratology (OK) and atropine 0.01% ophthalmic solution, both of which are effective procedures to slow axial elongation in children with myopia.

Study design

Prospective randomized clinical trial.

Methods

Japanese children aged 8–12 years with a spherical equivalent refractive error of ??1.00 to ??6.00 diopters were included. A total of 41 participants who had been wearing the OK lenses successfully for 3 months were randomly allocated into two groups to receive either the combination of OK and atropine 0.01% ophthalmic solution (combination group) or monotherapy with OK (monotherapy group). Subjects in the combination group started to use atropine 0.01% ophthalmic solution once nightly from 3 months after the start of OK. Axial length was measured every 3 months using non-contact laser interferometry (IOLMaster), and the axial length measurement at month 3 of OK therapy was used as the baseline value in both groups. The increase in axial length over 1 year was compared between the two groups.

Results

A total of 40 consecutive subjects (20 subjects in the combination group and 20 in the monotherapy group) were followed for 1 year. The increase in axial length over 1 year was 0.09?±?0.12 mm in the combination group and 0.19?±?0.15 mm in the monotherapy group (P?=?0.0356, unpaired t test).

Conclusion

During the 1-year follow-up, the combination of OK and atropine 0.01% ophthalmic solution was more effective in slowing axial elongation than OK monotherapy in children with myopia.

     

Haigis and SRKT formulae accuracy for intentional myopic overcorrection

Purpose

To investigate the influence of preoperative biometric parameters on the accuracy of Haigis and SRKT formulae in predicting postoperative target refraction.

Methods

Retrospective analysis of 108 eyes (70 patients) underwent uneventful phacoemulsification surgery with implant of Alcon-SN60WF intraocular lens (IOL). Forty-five eyes were intentionally targeted to myopia (?0.75 to ?1.25 dpt), while the others targeted between 0 and ?0.75 dpt. Preoperative axial length and keratometry (K) were measured with optical biometry (LENSTAR—Haag-Streit). Postoperative spherical equivalent was assessed 3 ± 2 months after surgery.

Results

There is a significant correlation between the mean keratometry (K) and the Haigis–SRKT prediction differences (P < 0.001; r = 0.749). Linear regression indicates that a decrease of 1 diopter (D) on K implies an increase of 0.23 D on the difference between formulae prediction. K alone does not influence the prediction error for both formulas. The difference between the two formulae is dependent on K (r = ?0.75; P < 0.01). Moreover, eyes with K <43.75 targeted at myopia (n = 23) showed a significant myopic shift of ?0.26 ± 0.09 dpt (P < 0.05) with Haigis, but a hyperopic shift of 0.24 ± 0.09 dpt (P < 0.05) with SRKT.

Conclusion

Divergences between Haigis and SRKT formulae cause uncertainty in choosing the IOL. Our results indicate that, in eyes with lower preoperative K, an IOL targeted at myopia might result in a small, but significant myopic shift with the Haigis formula, while a hyperopic shift with the SRKT formula.