Multifocal versus modified monovision corrections: A non-dispensing comparison of visual assessment in presbyopic neophytes

Purpose: To compare the visual performance of two simultaneous?vision soft multifocal contact lenses and to compare multifocal contact lens and its modified monovision counterpart in presbyopic neophytes. Methods: A double?masked, prospective, comparative study was conducted on 19 participants fitted with soft PureVision2 multifocal (PVMF) and clariti multifocal (CMF) lenses in random order. High? and low?contrast distance visual acuity, near visual acuity, stereopsis, contrast sensitivity, and glare acuity were measured. The measurements were conducted using multifocal and modified monovision design with one brand and then repeated with another brand of lens. Results: High?contrast distance visual acuity showed a significant difference between CMF (0.00 [?0.10–0.04]) and PureVision2 modified monovision (PVMMV; ?0.10 [?0.14–0.00]) correction (P = 0.003) and also between CMF and clariti modified monovision (CMMV; ?0.10 [?0.20–0.00]) correction (P = 0.002). Both modified monovision lenses outperformed CMF. The current study did not show any statistically significant difference between contact lens corrections for low?contrast visual acuity, near visual acuity, and contrast sensitivity (P > 0.01). Stereopsis at near distance was significantly lower with both modified monovision (PVMMV: 70 [50–85]; P = 0.007, CMMV: 70 [70–100]; P = 0.006) and with CMF (50 [40–70]; P = 0.005) when compared to spectacles (50 [30–70]). Glare acuity was significantly lower with multifocal (PVMF: 0.46 [0.40–0.50]; P = 0.001, CMF: 0.40 [0.40–0.46]; P = 0.007) compared with spectacles (0.40 [0.30–0.40]), but no significant difference was noted between the multifocal contact lenses (P = 0.033). Conclusion: Modified monovision provided superior high?contrast vision compared to multifocal correction. Multifocal corrections performed better for stereopsis when compared to modified monovision. In parameters like low?contrast visual acuity, near acuity, and contrast sensitivity, both the corrections performed similarly. Both multifocal designs showed comparable visual performances.

Assessment of knowledge, attitude, and practice of glaucoma among different cadres of optometrists

Purpose: To assess the level of knowledge, attitude, and clinical practice of glaucoma among optometry students and optometry practitioners with different years of clinical experience and academic background. Methods: A survey with 20 questions on knowledge, attitude, and practice (KAP) of glaucoma was prepared and self?administered to optometry students and optometry practitioners practicing in an eye hospital/clinic/optical with varied years of clinical experience and education qualification. Results: Among the 558 participants, 57% were optometry practitioners and 43% were students. The knowledge scores among optometry practitioners increased significantly with an increase in the years of clinical experience (P < 0.001). Participants with master’s degrees scored higher than participants with bachelor’s degrees (P = 0.12). There was no statistically significant difference in knowledge scores based on the type of clinical practice ? hospital, private practice, or optical (P = 0.39). Practicing optometrists who performed slit?lamp examination, gonioscopy, IOP measurements, and disc evaluation for the detection of glaucoma had significantly higher knowledge scores than those who did not perform these tests in their practice (P < 0.05). A positive attitude toward glaucoma learning through workshops and hands?on training was reported by optometrists and students. Conclusion: Knowledge about glaucoma was good among optometrists and optometry students and was better among those who handled the diagnostics. All the optometrists had a positive attitude toward enhancing their practice through proper training

Prevalence and causes of low vision and blindness in an urban population: The Chennai Glaucoma Study.

Aim: To evaluate the prevalence and causes of low vision and blindness in an urban south Indian population. Settings and Design: Population-based cross-sectional study. Exactly 3850 subjects aged 40 years and above from Chennai city were examined at a dedicated facility in the base hospital. Materials and Methods: All subjects had a complete ophthalmic examination that included best-corrected visual acuity. Low vision and blindness were defined using World Health Organization (WHO) criteria. The influence of age, gender, literacy, and occupation was assessed using multiple logistic regression. Statistical Analysis: Chi-square test, t-test, and multivariate analysis were used. Results: Of the 4800 enumerated subjects, 3850 subjects (1710 males, 2140 females) were examined (response rate, 80.2%). The prevalence of blindness was 0.85% (95% CI 0.6–1.1%) and was positively associated with age and illiteracy. Cataract was the leading cause (57.6%) and glaucoma was the second cause (16.7%) for blindness. The prevalence of low vision was 2.9% (95% CI 2.4–3.4%) and visual impairment (blindness + low vision) was 3.8% (95% CI 3.2–4.4%). The primary causes for low vision were refractive errors (68%) and cataract (22%). Conclusions: In this urban population based study, cataract was the leading cause for blindness and refractive error was the main reason for low vision.

Comparison of saccadic reaction time between normal and glaucoma using an eye movement perimeter.

Aim: To compare the saccadic reaction time (SRT) in both the central and peripheral visual fi eld in normal and glaucomatous eyes using eye movement perimetery (EMP). Materials and Methods: Fift y-four normal and 25 glaucoma subjects underwent EMP and visual fi eld testing on the Humphrey Field Analyser (HFA) 24-2 program. The EMP is based on infrared tracking of the corneal refl ex. Fift y-four test locations corresponding to the locations on the 24-2 HFA program were tested. SRTs at diff erent eccentricities and for different severities of glaucoma were compared between normal and glaucoma subjects. Results: Mean SRT was calculated for both normal and glaucoma subjects. Mann-Whitney U test showed statistically signifi cant (P < 0.001) diff erences in SRT’s between normal and glaucoma subjects in all zones. Conclusion: SRT was prolonged in eyes with glaucoma across diff erent eccentricities.

Long-term change in central corneal thickness from a glaucoma perspective.

Aim: To investigate the longitudinal change in central corneal thickness (CCT) over 3 years in patients with glaucoma. Materials and Methods: The Chennai Glaucoma Follow‑up Study, an offshoot of the Chennai Glaucoma Study, was designed to evaluate the progression of glaucoma. A cohort of participants in the Chennai Glaucoma Study that were suffering from glaucoma or were at a higher risk for glaucoma underwent comprehensive ophthalmic evaluation at the base hospital at 6‑month intervals during the years 2004 to 2007. The CCT (average of 10 readings) was measured between 11 am and 1 pm on any given day using an ultrasonic pachymeter. Patients with a history of ocular surgery, corneal disease and usage of topical carbonic anhydrase inhibitor were excluded. No patient was a contact lens wearer. Results: One hundred and ninety‑six patients (84 male, 112 female) met the inclusion criteria. We analyzed data from the right eye. The mean age of the patients was 59.97 ± 9.06 years. Fifty‑nine (30.1%) of the patients were diabetic. The mean change in CCT (CCT at first patient visit – CCT at last patient visit) was 3.46 ± 7.63 µm. The mean change in CCT was 0.75 µm per year (R2 = 0.00). Age, gender, intraocular pressure at the first patient visit and diabetic status had no significant influence on the magnitude of change in CCT. Conclusion: A carefully obtained CCT reading by a trained examiner need not be repeated for at least 3 years as long as the ocular and systemic factors known to affect the measurement of CCT are constant.

Importance of population-based studies in clinical practice.

In the last decade, there have been reports on the prevalence of glaucoma from the Vellore Eye Survey, Andhra Pradesh Eye Diseases Survey, Aravind Comprehensive Eye Survey, Chennai Glaucoma Study and West Bengal Glaucoma Study. Population-based studies provide important information regarding the prevalence and risk factors for glaucoma. They also highlight regional differences in the prevalence of various types of glaucoma. It is possible to gather important insights regarding the number of persons affected with glaucoma and the proportion with undiagnosed disease. We reviewed the different population-based studies from India and compare their findings. The lacunae in ophthalmic care that can be inferred from these studies are identified and possible reasons and solutions are discussed. We also discuss the clinical relevance of the various findings, and how it reflects on clinical practice in the country. Since India has a significantly high disease burden, we examine the possibility of population-based screening for disease in the Indian context.