Revisiting the impact of phenylephrine hydrochloride on static and dynamic accommodation.

Purpose: Phenylephrine hydrochloride (PHCl), a commonly used mydriatic agent, causes a small but significant deterioration of accommodation. The relative roles of pharmacology and optics in this deterioration, however, remain unascertained. The study determined the combined impact of PHCl concentration (pharmacology) and pupil size (optics) on the static and dynamic characteristics of accommodation. Materials and Methods: A total of 16 emmetropic Indian adults viewed a high-contrast visual target that switched between 67 and 33 cm viewing distance (1.5D stimulus) with their right eye (left eye occluded using infrared transmitting filter) through natural pupils and through 8, 6, 4, and 1 mm diameter artificial pupils. This protocol was repeated once without PHCl and once each with 2.5%, 5%, and 10% PHCl. Consensual accommodation of the left eye was recorded using infrared photorefraction (60 Hz). Results: Relative to no PHCl, the horizontal pupil diameter of left eye was significantly larger (P < 0.001) and the response magnitude and peak velocity of accommodation and disaccommodation were modestly but significantly smaller (P < 0.02 for all) for all concentrations of PHCl tested. There was no significant difference in these parameters across the three drug concentrations (P > 0.4 for all). The response magnitude and peak velocity also decreased significantly with pupil diameter, at similar rates for the no PHCl and the three PHCl conditions (P < 0.001 for all). Conclusion: The reduction in accommodative performance with all drug concentrations and with pupil diameter suggests independent roles of pharmacology and optics in determining accommodative performance with PHCl. The reduction in accommodative performance is, however, modest and may be clinically irrelevant in Indian eyes.

Bilateral loss of light reflex and accommodation following 360 peripheral retinal laser therapy

We report a case of bilateral loss of pupillary light reflex and accommodation following 360° peripheral retinal laser therapy. A 24 years old male underwent prophylactic laser barrage for peripheral retinal lattice degenerations. Soon after the procedure, he developed bilateral loss of pupillary light reflex and accommodation. The patient faced difficulty while doing near work. On instillation of 0.125% pilocarpine, both pupils demonstrated the phenomenon of denervation supersensitivity. Damage to the short ciliary nerves was the most likely mechanism responsible for this adverse outcome

Fator de correção para indivíduos com capacidade acomodativa baseado no uso do refrator automático / Correction factor for individuals with accommodative capacity based on automated refractor

OBJETIVO: Pesquisar um fator de correção para avaliação do erro refrativo sem a utilização da cicloplegia. MÉTODOS: Foram estudados 623 pacientes (1.246 olhos), de ambos os sexos, com idade entre 3 e 40 anos. As refratometrias estática e dinâmica foram obtidas usando-se o refrator automático Shin-Nippon Accuref-K 9001. A cicloplegia foi obtida com a instilação de uma gota de colírio ciclopentolato a 1 por cento, com refratometria estática 30 minutos após. Os dados foram submetidos à análise estatística usando a técnica do modelo de regressão linear e modelo de regressão múltipla do valor dióptrico com e sem cicloplegia, em função da idade. RESULTADOS: A correlação entre valores dióptricos sem e com cicloplegia quanto ao erro astigmático variou de 81,52 por cento a 92,27 por cento. Quanto ao valor dióptrico esférico, a correlação foi menor (53,57 por cento a 87,78 por cento). O mesmo se observou em relação ao eixo do astigmatismo (28,86 por cento a 58,80 por cento). O modelo de regressão múltipla em função da idade mostrou coeficiente de determinação múltiplo maior para a miopia (86,38 por cento) e astigmatismo (79,79 por cento). O menor coeficiente foi observado para o eixo do astigmatismo (17,70 por cento). CONCLUSÃO: Avaliando-se os erros refrativos com e sem cicloplegia, observou-se alta correlação nas ametropias cilíndricas. Foram desenvolvidas equações matemáticas como fator de correção para refratometrias dos pacientes sem cicloplegia, portadores de ametropias cilíndricas e esféricas.

PURPOSE: To determine a correction factor for refractive errors evaluated without cycloplegy effect. METHODS: A study was made with 623 patients (1,246 eyes) of both sexes, aging between 3 and 40 years old. The dynamic and static refractometries were obtained using the automated refractor Shin-Nippon Accuref-K 9001. 1 percent Cyclopentolate was dropped and the static refractometry was performed in 30 minutes. Data were analyzed using the linear regression model and the multiple regression model of the diopter values with and without cycloplegy effect according to age. RESULTS: The correlation between the astigmatism diopter values with and without cicloplegy ranged from 81.52 percent to 92.27 percent. Analyzing the spherical diopter values, the correlation was lower (53.57 percent to 87.78 percent). The astigmatism axis also revealed low correlation values (28.86 percent to 58.80 percent). The multiple regression model according to age demonstrated multiple determination coefficient with high values for myopia (86.38 percent) and astigmatism (79.79 percent). The lowest multiple determination coefficient was observed for astigmatism axis (17.70 percent). CONCLUSION: It was possible to demonstrate a high correlation in refractive errors with and without cycloplegy effect on the cylindrical ametropies. Mathematical formules, for cylindrical and spherical ametropies, were presented as a correction factor for refraction of the patients not submitted to cycloplegy.

The Studies on the Residual Accommodation of Koreans I. The Residual Accommodation under 1% Atropine and 5% Homatropine Cycloplegia

This study was conducted to determine how much of a residua1 accommodation remained one hour after three instillations of atropine or homatropine in 384 eyes of younger Koreans. The amount of residual accommodation was measured by the blur point method, and the following results were obtained. 1) The average amount of the residual accommodation was 0.96 D under l% atropine and 1.42 D under 5% homatropine. 2) In comparing the two cycloplegic agents, 1% atropine was found to be more effective than 5% homatropine. 3) Residual accommodation under l% atropine and 5% homatropine showed gradually decrease in older patients. 4) No sex difference was found.