The formation of cataract is earlier in the dominant eye

Ocular dominance in cataract surgery: research status and progress

Ocular dominance (OD), a commonly used concept in clinical practice, plays an important role in optometry and refractive surgery. With the development of refractive cataract surgery, the refractive function of the intraocular lens determines the achievement of the postoperative full range of vision based on the retinal defocus blur suppression and binocular monovision principle. Therefore, OD plays an important role in cataract surgery. OD is related to the visual formation of the cerebral cortex, and its plasticity suggests that visual experience can influence the visual system. Cataract surgery changes the visual experience and transforms the dominant eye, which confirms the plasticity of the visual system. Based on the concept and mechanism of OD, this review summarizes the application of OD in cataract surgery.

Handing it to pterygium: Explaining pterygium laterality

PURPOSE

To evaluate any correlation between pterygium laterality and patient handedness.

METHODS

Our study represents a retrospective observational study of a series of consecutive pterygium patients recruited from two centres. Each patient was assessed for their handedness which was compared to the laterality of their presenting pterygium. Patients that possessed bilateral disease comparisons between pterygium size and handedness were made. Correlation statistics were performed to compare patient handedness and pterygium location (right or left). For patients possessing bilateral disease only, the pre-surgical differences between lengths and areas of pterygium were calculated and compared.

RESULTS

A total of 219 patients were recruited into our study. 172 patients possessed unilateral disease and in 47 patients, the disease was bilateral. A significant association was identified between handedness and pterygium laterality (p < 0.001). Patients with right-sided pterygia were more likely to be right-handed (OR 2.327) and left-sided presentations who were more likely to be left-handed (OR 5.717). For bilateral presentations, patients were found to have longer (mean increase 3.50 ± 0.47 mm) and larger (mean increase 4.38 ± 0.48 mm²) pterygia in the eye ipsilateral to their dominant hand.

CONCLUSIONS

A new insight of handedness as a contributing factor to pterygium laterality is consistent with evidence relating to the asymmetrical development of cortical cataract as well as to theories underlying the geometry of ocular UV exposure. A more complete understanding of factors contributing to ocular insolation may further inform as to improved protective measures and provides further evidence for the role of peripheral light focusing in pterygium pathogenesis.

Cataract surgery in Kinshasa-Is there a place for "Monovision"?

OBJECTIVES

Monovision is a method of correcting presbyopia where one eye is focused for far and the other for near vision. It is a simple, cost-effective approach to overcome the loss of accommodation with age and to become spectacles independent.

METHODOLOGY

About 50 patients, where bilateral cataract extraction was indicated, were included in this study performed at the St. Joseph's Eye Hospital in Kinshasa (DR Congo). Small incision cataract surgery technique (SICS) was applied with the implantation of 6 mm PMMA lenses in the capsular bag. IOL refractive power choice was made to achieve a post-operative refraction of -0.5 dpt for the eye selected for far vision. The second eye received an implant heading for a post-operative myopia of -1.5 dpt suitable for intermediated and near vision. According to the literature, monovision criteria have been regarded as fulfilled when (a) far vision was 0.5 (logMAR) or better and (b) near vision was P3 (0.40, Decimal 32 cm) or better. Spectacle dependence after bilateral cataract surgery heading for monovision was analysed using a dedicated questionnaire.

RESULTS

Out of all 50 patients 22 (44%) fulfilled the above defined criteria of monovision in terms of post-operative refraction and visual acuity. About 19 out of these 22 (86.3%) patients were happy without glasses. Two of them used bifocal spectacles, whereas the remaining patient refused spectacles. About 28 patients did not fulfill monovision criteria. Out of these 28 patients, however, 9 (32.1%) of them are happy without glasses.

CONCLUSION

In view of the described local circumstances aiming for monovision after bilateral cataract surgery is a suitable approach to optimise cataract surgical outcomes with no extra costs for surgery but considerable improvement of patient's visual performance in daily life.

The treatment of recurrent conjunctival and corneal intraepithelial neoplasia with interferon alfa-2b and retinoic acid: ~9 years' follow-up on tumor control

PURPOSE

To evaluate the long-term follow-up of recurrent conjunctival and corneal intraepithelial neoplasia (CCIN) treated with combination topical interferon alfa-2b and retinoic acid (I/RA).

METHODS

Our study represents a retrospective observational interventional series of 82 eyes from 82 patients from a single institution, reviewed for CCIN. All were administered topical interferon alfa-2b 1 million IU/mL QID and retinoic acid 0.01% every other day. Patients had been diagnosed by biopsy. A Kaplan-Meier survival analysis, Wilcoxon signed-rank test and a multivariate logistic regression were statistical tests used to correlate recurrence with patient and tumor variables.

RESULTS

79 eyes assessed for CCIN diagnoses and treated with I/RA achieved tumor resolution. The median tumor-free follow-up was ~109.1 months with a median time to resolution being ~2.8 months. Our median treatment duration was ~11.3 months. The greatest difference in the mean total residual tumor size was identified between Months 0-1 [-7.63 mm²]. The difference in mean total residual tumor size remained significant till 36-months. A statistically significant correlation with recurrence was identified for biopsy type [OR 0.138]. 6 patients experienced papillary conjunctivitis which resolved with dosage reduction.

CONCLUSIONS

Combination I/RA was effective in treating CCIN lesions with few transient side effects. The combination of retinoids and interferons may represent a viable topical therapeutic agent with an extended tumor-free follow-up and a large proportion of our study's patients achieving >10 year's tumor-free follow-up. Our treatment duration is long, but by cost-comparing surgical against medical interventions, topical I/RA may serve as a safe and effective alternative.

Lens Opacity and Hydrogen Sulfide in a New Zealand Geothermal Area

PURPOSE

Hydrogen sulfide (H2S) is a highly toxic gas with well-established, acute irritation effects on the eye. The population of Rotorua, New Zealand, sited on an active geothermal field, has some of the highest ambient H2S exposures in the world. Evidence from ecological studies in Rotorua has suggested that H2S is associated with cataract. The purpose of the present study was, using more detailed exposure characterization, clinical examinations, and anterior eye photography, to more directly investigate this previously reported association.

METHODS

Enrolled were 1637 adults, ages 18 to 65, from a comprehensive Rotorua primary care medical register. Patients underwent a comprehensive ophthalmic examination, including pupillary dilation and lens photography to capture evidence of any nuclear opacity, nuclear color, and cortical and posterior subcapsular opacity. Photographs were scored for all four outcomes on the LOCS III scale with decimalized interpolation between the exemplars. H2S exposure for up to the last 30 years was estimated based on networks of passive samplers set out across Rotorua and knowledge of residential, workplace, and school locations over the 30 years. Data analysis using linear and logistic regression examined associations between the degree of opacification and nuclear color or cataract (defined as a LOCS III score ≥2.0) in relation to H2S exposure.

RESULTS

No associations were found between estimated H2S exposures and any of the four ophthalmic outcome measures.

CONCLUSIONS

Overall, results were generally reassuring. They provided no evidence that H2S exposure at the levels found in Rotorua is associated with cataract. The previously found association between cataract and H2S exposure in the Rotorua population seems likely to be attributable to the limitations of the ecological study design. These results cannot rule out the possibility of an association with cataract at higher levels of H2S exposure.

Differences by Sex and Handedness in Right and Left Femur Bone Mineral Densities

Left-handedness was reported to be a risk factor for accident-related injuries, head injuries, traumatic brain injuries, sport-related injuries, and bone breaks and fractures. As decreased bone mineral density is a good marker of bone fractures, the femoral bone mineral densities of normal left-handed university students were compared with those of right-handed students. Hand preference of 66 men and 47 women was assessed using the Edinburgh Handedness Inventory. Measures of bone mineral density with a Hologic QDR-4500W (S/N 48403) densitometer showed bone mineral densities of both right and left proximal femur regions were higher in right-handed than in left-handed students. These results are consistent with the claim that left-handed participants had higher trauma and injury risk. Also, these results may explain the sex-related differences by handedness for susceptibility in accident-related injuries such as bone fractures.