The Association of Central corneal thickness with Intra-ocular Pressure and Refractive Error in a Nigerian Population

The purpose of this study was to determine the variation of central corneal thickness (CCT) with intraocular pressure (IOP) and spherical equivalent refractive error. A total of thirty-nine (N=39) subjects within 20-75 years with mean age 45.2 ± 15.4 years were used for this study. The central corneal thickness was assessed with the Corneo-Gage plus ultrasonic Pachymeter, the IOP with slit-lamp mounted Goldmann applanation tonometer and refractive status by Protec 2000 autorefractor, phoropter and trial lens set. Results obtained showed that there was no linear correlation between CCT and spherical equivalent errors, although the association between them was significant (p<0.05). The linear correlation between CCT and IOP was not statistically significant. The central corneal thickness was weakly correlated with age; with increasing age the central corneal thickness decreases. Neither the central corneal thickness nor the intraocular pressure was affected by gender

A Survey on Ophthalmia Neonatorum in Benin City, Nigeria (Emphasis on gonococcal ophthalmia)

The purpose of the study was to investigate the incidence of gonococcal ophthalmia neonatorum considering its ability to lead to childhood blindness through corneal ulceration and scarification. Eye swabs were obtained from 330 neonates of 1-5 days in the hospitals of study. Of these, 248 yielded growth and six bacterial genera were identified using standard techniques. Staphylococcus aureus was the most prevalent (60.5%) while Neisseria gonorrhoeae accounted for 1.7%. Susceptibility patterns of bacterial isolates to four antibiotics were determined using Disk-diffusion tests. Staphylococcus aureus and Neisseria gonorrhoeae showed 62.5 and 100% susceptibility to Erythromycin while 66.7% of Escherichia coli and Klebsiella and 62.5% of Pseudomonas aeruginosa were susceptible to Gentamicin. The incidence of gonococcal ophthalmia neonatorum for the period of study was 8.9 (cases per 1,000 live births). Prevention is through ocular prophylaxis by the application of either 1% silver nitrate ophthalmic solution or 0.5% erythromycin ointment to the neonates’ eyes some hours after birth. This would help to preserve vision and reduce to the barest minimum the incidence of childhood blindness

Age, gender, corneal diameter, corneal curvature and central corneal thickness in Nigerians with normal intra ocular pressure

AbstractPurposeTo investigate the relationship between age, gender, corneal diameter, central corneal curvature, central corneal thickness (CCT) and intraocular pressure in Nigerians with normal intraocular pressure.MethodsOne hundred and thirty eyes from 130 subjects (mean age=47.8±16.8 years) including 77 males and 53 females were recruited. CCT was measured by ultrasound pachymetry, intraocular pressure was determined by non-contact tonometry, horizontal and vertical corneal diameters were measured with a ruler and central corneal curvature was measured by keratometry.ResultsThe mean values obtained were as follows: CCT=548.97±34.28μm, IOP=15.61±2.69mmHg, average corneal curvature (AVK)=42.98±1.19 D, horizontal corneal diameter (HVID)=11.39±0.69mm and vertical corneal diameter (VVID)=10.51±0.50mm. There was a significant effect of age on CCT (r=−0.35, p<0.001). A 10-year-increase in age was associated with a 7.0μm decrease in CCT. Males had significantly wider HVID than females (p=0.03). Subjects in older age groups have narrower HVID and VVID. Corneal curvature, corneal diameter and gender did not significantly affect CCT.ConclusionCCT of normotensive Nigerian adults decreases with increasing age. There was no correlation between CCT and IOP in normotensive subjects. CCT was not significantly influenced by gender, corneal curvature and corneal diameter

Bacterial adhesion to Conventional and Silicone hydrogel contact lenses

Purpose: The aim of this study was to investigate the adhesion of bacteria to worn silicone hydrogel and conventional soft contact lenses.Methods: Bacterial adhesion experiments / assays were performed on 24 worn and 6 unworn soft contact lenses each of different materials (high- and low- gas permeable lenses) using the strains such as Pseudomonas aeruginosa ATCC 27853 and Staphylococcus aureus ATCC 25923.Results: P. aeruginosa adhered in increased number to worn than unworn Lotrafilcon A and conventional lenses. However, a higher number of P. aeruginosa adhered to unworn than worn Lotrafilcon B, the difference in the mean adhesion was not significant (p = 0.66). S. aureus adhered in significantly decreased number to worn Lotrafilcon A, nelfilcon A, nesofilcon A, etafilcon A and omafilcon A (p&lt;0.05); butsignificantly higher number adhered to worn than unworn polymacon (p&lt;0.05). Lens wear had no effect on the adhesion of S. aureus to Lotrafilcon B (p&gt;0.05). The least adhesion of P. aeruginosa to worn contact lenses was seen with polymacon, while S. aureus adhered in least number to worn Lotrafilcon A compared to the other contact lens materials that demonstrated the same trend in adhesion.Conclusion: The higher adhesion of P. aeruginosa to worn lenses is consistent with the claim that it is the most implicated in all culture-positive contact lens related bacterial keratitis. Lens wear has different effects on bacterial adhesion, which may be due to type of lens materials and bacterial species/genera studied. Keywords: Silicone hydrogel lenses, conventional lenses, Pseudomonas aeruginosa, Staphylococcus aureus, bacterial adhesion

The Effect of Smokeless Tobacco on Intra-Ocular Pressure in a Nigerian Population

The study was conducted to find out the effect of smokeless tobacco (ST) on the intraocular pressure (IOP) among non-smokers and smokers. Thirty-seven healthy volunteers of between 19–30 years age, classified into two groups, non-smokers (n=22) and- smokers (n=15), were used. The IOPs of the right eyes were measured before (0min) and 1, 3 and 5mins after sniffing 40mg ST with Pulsair 2000 tonometer. Among non-smokers and smokers, the difference in mean IOP at different times (0min, 1min, 3mins and 5mins) was statistically significant by one-way ANOVA (p<0.05). Post hoc analysis using Duncan multiple range (DMR) test showed that the peak IOP was at 1min after sniffing ST. The difference in IOP before sniffing ST between smokers and non-smokers was statistically significant by Mann-Whitney test (p<0.05). Also the difference in the peak time of 1min between smokers and non-smokers was statistically significant (p<0.05). It was concluded that ST stimulates aqueous humour formation thereby tending to raise IOP and this could enhance the chances of developing ocular hypertension in patients that are predisposed to glaucoma

The validity and reliability of the handheld SW-100 autokeratometer

Background: The agreement of new instruments or clinical tests with other instruments or tests defines the possibility of these being used interchangeably. Aim: To investigate the validity and reliability of the SW-100 autokeratometer using a Bausch & Lomb (B&L) keratometer as the ‘gold standard’. Methods: Eighty subjects (80 right eyes) aged between 21 and 38 years were recruited. For intra-test repeatability, two measurements of the corneal radius of curvature were taken with the SW-100 and B&L keratometers. Forty of the 80 subjects participated in the inter-test repeatability measurement. Results: Corneal radius of curvature was found to be statistically different between the two instruments (p < 0.001), with the SW-100 providing slightly flatter values of 0.11 mm and 0.05 mm for the horizontal and vertical meridians, respectively, than the B&L keratometer. The average corneal curvature was 0.07 mm flatter with the SW-100 autokeratometer than with the B&L device. Agreement between the SW-100 and B&L keratometers’ axes was 45% within ± 5°, 60.3% within ± 10°, 78.8% within ± 15°, 80.3% within ± 20°, and 88.7% within ± 40°. Intertest repeatability was better for the B&L device than the SW-100 and showed no significant difference between the two sessions. Both instruments demonstrated comparable intrasession repeatability. As such, both instruments were comparatively reliable (per coefficients of repeatability). The range of limits of agreement of ± 0.14 mm (horizontal meridian) and ± 0.17 mm (vertical meridian) between the SW-100 and B&L devices showed good agreement. Conclusion: The results suggest that the SW-100 autokeratometer is a reliable and objective instrument that, however, provides flatter radii of curvature measurements than the B&L keratometer. A compensating factor incorporated into the instrument could reduce the difference between the two instruments and make them more interchangeable

Central corneal thickness and axial length in an adult Nigerian population

Purpose: The aim of this study was to determine the relationship between central corneal thickness (CCT) and axial length (AL) in adult Nigerians. Methods: A total of ninety-five (n = 95) subjects aged between 20 and 69 years consisting of 56 males and 39 females were recruited for this study. The CCT was measured by ultrasound pachymetry using SW-1000P ultrasound pachymeter (Tianjin Suowei Electronics Technologies LTD, China) and the axial length by A-Scan ultrasonography using I-2100 A Scan Biometer (Cima Technology Inc., USA). Results: The average CCT and AL were 547.0 ± 29.5 μm and 23.5 ± 0.70 mm, respectively. Age inversely correlated with CCT (r = −0.32, p = 0.02), but had no effect on AL (r = 0.082, p = 0.43). The association between CCT and AL showed an inverse trend but was not statistically significant (r = −0.10, p = 0.32). Neither CCT nor AL was affected by gender (p = 0.11; p = 0.63, respectively). Conclusion: CCT decreases with age, but AL was not affected by age. The association between CCT and AL was not significant. Gender did not show any statistically significant effect on CCT and AL

The Effect of Smokeless Tobacco on Intra-Ocular Pressure in a Nigerian Population

The study was conducted to find out the effect of smokeless tobacco (ST) on the intraocular pressure (IOP) among non-smokers and smokers. Thirty-seven healthy volunteers of between 19?30 years age, classified into two groups, non-smokers (n=22) and- smokers (n=15), were used. The IOPs of the right eyes were measured before (0min) and 1, 3 and 5mins after sniffing 40mg ST with Pulsair 2000 tonometer. Among non-smokers and smokers, the difference in mean IOP at different times (0min, 1min, 3mins and 5mins) was statistically significant by one-way ANOVA (p<0.05). Post hoc analysis using Duncan multiple range (DMR) test showed that the peak IOP was at 1min after sniffing ST. The difference in IOP before sniffing ST between smokers and non-smokers was statistically significant by Mann-Whitney test (p<0.05). Also the difference in the peak time of 1min between smokers and non-smokers was statistically significant (p<0.05). It was concluded that ST stimulates aqueous humour formation thereby tending to raise IOP and this could enhance the chances of developing ocular hypertension in patients that are predisposed to glaucoma